Following a PhD in water technology at UMIST in 1991, I had a research career in the UK and more recently in Australia. My research expertise covers sampling strategy, passive sampling, trace analysis, remote sensing of vehicle emissions, contaminant transport and transformation processes, advanced wastewater treatment using chemical oxidation, reduction by nano zero-valent iron, adsorption on biochar, biodegradation and visible photocatalysis, wastewater reuse, and energy recovery from waste.
Fellow of the Royal Society of Chemistry
Fellow of the Higher Education Academy
Scientific assessor for funding agencies including the EU, Luxembourg National Research Fund, NERC, Defra, US NSF, Fondazione Cariplo, Romanian National Council for Development and Innovation, Chinese Ministry of Science and Technology, Australian Research Council.
- Water and wastewater treatment technology
- Renewable energy generation
- Remote sensing of vehicle emissions
- Environmental processes
- Contaminated land remediation
- Pollution control technologies
- Environmental risk assessment
- Industrial case studies
- Research skills
Huang, Y., Organ, B., Zhou, J.L., Surawski, N.C., Hong, G., Chan, E.F.C. & Yam, Y.S. 2018, 'Emission measurement of diesel vehicles in Hong Kong through on-road remote sensing: Performance review and identification of high-emitters.', Environmental pollution (Barking, Essex : 1987), vol. 237, pp. 133-142.View/Download from: Publisher's site
A two-year remote sensing measurement program was carried out in Hong Kong to obtain a large dataset of on-road diesel vehicle emissions. Analysis was performed to evaluate the effect of vehicle manufacture year (1949-2015) and engine size (0.4-20 L) on the emission rates and high-emitters. The results showed that CO emission rates of larger engine size vehicles were higher than those of small vehicles during the study period, while HC and NO were higher before manufacture year 2006 and then became similar levels between manufacture years 2006 and 2015. CO, HC and NO of all vehicles showed an unexpectedly increasing trend during 1998-2004, in particular 6001 cc vehicles. However, they all decreased steadily in the last decade (2005-2015), except for NO of 6001 cc vehicles during 2013-2015. The distributions of CO and HC emission rates were highly skewed as the dirtiest 10% vehicles emitted much higher emissions than all the other vehicles. Moreover, this skewness became more significant for larger engine size or newer vehicles. The results indicated that remote sensing technology would be very effective to screen the CO and HC high-emitters and thus control the on-road vehicle emissions, but less effective for controlling NO emissions. No clear correlation was observed between the manufacture year and percentage of high-emitters for 3000 cc vehicles. However, the percentage of high-emitters decreased with newer manufacture year for larger vehicles. In addition, high-emitters of different pollutants were relatively independent, in particular NO emissions, indicating that high-emitter screening criteria should be defined on a CO-or-HC-or-NO basis, rather than a CO-and-HC-and-NO basis.
Belhaj, D., Athmouni, K., Frikha, D., Kallel, M., El Feki, A., Maalej, S., Zhou, J.L. & Ayadi, H. 2017, 'Biochemical and physiological responses of halophilic nanophytoplankton (Dunaliella salina) from exposure to xeno-estrogen 17-ethinylestradiol.', Environmental science and pollution research international, vol. 24, no. 8, pp. 7392-7402.View/Download from: UTS OPUS or Publisher's site
The environmental impacts of various pollutants on the entire levels of organisms are under investigation. Among these pollutants, endocrine-disrupting compounds (EDCs) present a serious hazard, even though the environmental significance of these compounds remains basically unknown. To drop some light on this field, we assessed the effects of a 11-day exposure of 17-ethinylestradiol (EE2) on the growth, metabolic content, antioxidant response, oxidative stress, and genetic damage of Dunaliella salina, isolated from Tunisian biotopes. The results showed that at 10 ng L-1, EE2 could stimulate the growth of D. salina and increase its cellular content of photosynthetic pigments and metabolites; however, it did not significantly increase the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) or the level of malondialdehyde (MDA) and hydrogen peroxide (H2O2). In contrast, exposure to high levels of EE2 concentrations significantly inhibited the growth of D. salina (P < 0.05), decreased the cellular content of photosynthetic pigments, increased the cellular content of all of the metabolites and the SOD activity, and inhibited CAT and GPx activities. Nevertheless, the balance between oxidant and antioxidant enzymes was disrupted because H2O2 content along with MDA content simultaneously increased. Contrary to expected results, DNA damage (strand breaks) decreased after the exposure of algae to EE2. The results of this study suggest that EE2 toxicity could result in environmental impacts with consequences on the whole aquatic community. Graphical abstract.
Belhaj, D., Frikha, D., Athmouni, K., Jerbi, B., Ahmed, M.B., Bouallagui, Z., Kallel, M., Maalej, S., Zhou, J. & Ayadi, H. 2017, 'Box-Behnken design for extraction optimization of crude polysaccharides from Tunisian Phormidium versicolor cyanobacteria (NCC 466): Partial characterization, in vitro antioxidant and antimicrobial activities.', International journal of biological macromolecules, vol. 105, no. Pt 2, pp. 1501-1510.View/Download from: UTS OPUS or Publisher's site
In this study, response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to optimize the aqueous extraction of crude polysaccharides from Tunisian cyanobacteria Phormidium versicolor (NCC 466). The optimal extraction conditions with an extraction yield of 21.56±0.92% were as follows: extraction temperature at 81.05°C, extraction time of 3.99h, and water to raw material ratio of 21.52mLg-1. Crude Phormidium versicolor polysaccharides (CPv-PS) are found to be a hetero-sulfated-anionic polysaccharides that contained carbohydrate (79.37±1.58%), protein (0.45±0.11%), uronic acids (4.37±0.19%) and sulfate (6.83±0.28%). The carbohydrate fraction was composed of arabinose, xylose, ribose, rhamnose, N-acetyl glucosamine, galactose, glucose, mannose, glucuronic acid and saccharose with corresponding mole percentages of 2.41, 14.58, 2.18, 6.23, 7.04, 28.21, 26.04, 3.02, 0.86 and 5.07, respectively. Evaluation of the antioxidant activity in vitro suggested that CPv-PS strongly scavenged radicals, prevented bleaching of -carotene and reduced activity. Furthermore, the CPv-PS exhibited effective antimicrobial properties.
Altaee, A., Zaragoza, G., Drioli, E. & Zhou, J. 2017, 'Evaluation the potential and energy efficiency of dual stage pressure retarded osmosis process', Applied Energy, vol. 199, pp. 359-369.View/Download from: Publisher's site
© 2017 Power generation by means of Pressure Retarded Osmosis (PRO) has been proposed for harvesting the energy of a salinity gradient. Energy recovery by the PRO process decreases along the membrane module due to depleting of the chemical potential across the membrane and concentration polarization effects. A dual stage PRO (DSPRO) design can be used to rejuvenate the chemical potential difference and reduce the concentration polarization on feed solution. Several design configurations were suggested for the membrane module arrangements in the first and second stage of the PRO process. PRO performance was evaluated for a number of salinity gradients proposed by coupling Dead Sea water or Reverse Osmosis (RO) brine with seawater or wastewater effluent. Maximum specific energy of inlet and outlet feeds was calculated using a developed computer model to identify the amount of recovered and remaining energy. Initially, specific power generation by the PRO process increased by increasing the number of modules of the first stage. Maximum specific energy is calculated along the PRO module to understand the degradation of the maximum specific energy in each module before introducing a second stage PRO process. Adding a second stage PRO process resulted in a sharp increase of the chemical potential difference and the specific energy yield of the process. Between 10% and 13% increase of the specific power generation was achieved by the DSPRO process for the Dead Sea-seawater salinity gradient depending on the dual stage design configuration. For Dead Sea-RO brine, 12–16% increase of the specific power generation was achieved by the dual stage PRO process. For Dead Sea-wastewater and RO brine-wastewater, a neutral and sometimes negative impact occurred when a second stage PRO process was introduced. We concluded that, for a given draw solution concentration, dual stage performs better than the conventional PRO process at high feed salinities, yet requires lower hydraulic p...
Altaee, A., Zhou, J., Alhathal Alanezi, A. & Zaragoza, G. 2017, 'Pressure retarded osmosis process for power generation: Feasibility, energy balance and controlling parameters', Applied Energy, vol. 206, pp. 303-311.View/Download from: Publisher's site
© 2017 The feasibility of pressure-retarded osmosis (PRO) for power generation was evaluated with consideration of the energy inputs and losses in the process. The effects of the concentration polarization, reverse salt diffusion, and external resistance at the membrane porous layer were quantified, for the first time, along the membrane module to determine their contributions to the energy loss in the PRO process. Conc entration polarization was responsible for up to 40% of the energy loss during the PRO process. However, increasing the PRO membrane modules from 1 to 4 resulted in a variable increase of the energy output depending on the salinity gradient. The energy requirements for draw and feed solution pretreatment were estimated to be over 38% of the total energy inputs. Results showed that coupling seawater (SW) with river water (RW) was unable to generate sufficient energy to compensate for the energy inputs and losses during the PRO process. With 0.39 kwh/m 3 maximum specific energy in the PRO process, the energy yield of reverse osmosis brine (ROB)-wastewater (WW) salinity gradient was slightly greater than the total energy inputs, although using Dead Sea-SW/ROB salinity gradient was more promising. Overall, the primary current limitation is the lack of suitable PRO membranes that can withstand a high hydraulic pressure.
Xu, B., Ahmed, M.B., Zhou, J.L., Altaee, A., Wu, M. & Xu, G. 2017, 'Photocatalytic removal of perfluoroalkyl substances from water and wastewater: Mechanism, kinetics and controlling factors.', Chemosphere, vol. 189, pp. 717-729.View/Download from: UTS OPUS or Publisher's site
This review focuses on heterogeneous photocatalysis of perfluoroalkyl substances (PFAS) which are of worldwide concern as emerging persistent organic contaminants. Heterogeneous photocatalysis is an effective and advanced technology for PFAS removal from water with relatively high efficacy. During photocatalysis, various short chain perfluorocarboxylic acids (PFCA) are produced as intermediates and the efficacy is related to the photo-generated hole (h+) and photo-generated electron (e-). PFAS photodegradation in water under UV irradiation is most effective by using In2O3 as the catalyst, followed by Ga2O3 and TiO2. Significantly, modifying the chemical composition or morphology of the catalyst can improve its efficacy for PFAS removal. In2O3 porous nanoplates were found to have the best performance of 100% PFAS decomposition under UV light with rate constant (kt) and half-time (1/2) of 0.158 min-1 and 4.4 min, respectively. Catalysts perform well in acidic solution and increasing temperature to a certain extent. The photocatalytic performance is reduced when treating wastewater due to the presence of dissolved organic matter (DOM), with the catalysts following the order: needle-like Ga2O3 > In2O3 > TiO2. Future studies should focus on the development of novel photocatalysts, and their immobilization and application for PFAS removal in wastewater.
Sornalingam, K. 2017, 'Photocatalysis of estrone in water and wastewater: Comparison between Au-TiO2 nanocomposite and TiO2, and degradation by-products', Science of the Total Environment, vol. Volumes 610–611, pp. 521-530.View/Download from: UTS OPUS
Abdolali, A., Ngo, H.H., Guo, W., Zhou, J.L., Zhang, J., Liang, S., Chang, S.W., Nguyen, D.D. & Liu, Y. 2017, 'Application of a breakthrough biosorbent for removing heavy metals from synthetic and real wastewaters in a lab-scale continuous fixed-bed column.', Bioresource Technology, vol. 229, pp. 78-87.View/Download from: UTS OPUS or Publisher's site
A continuous fixed-bed study was carried out utilising a breakthrough biosorbent, specifically multi-metal binding biosorbent (MMBB) for removing cadmium, copper, lead and zinc. The effect of operating conditions, i.e. influent flow rate, metal concentration and bed depth was investigated at pH 5.5±0.1 for a synthetic wastewater sample. Results confirmed that the total amount of metal adsorption declined with increasing influent flow rate and also rose when each metal concentration also increased. The maximum biosorption capacities of 38.25, 63.37, 108.12 and 35.23mg/g for Cd, Cu, Pb and Zn, respectively, were achieved at 31cm bed height, 10mL/min flow rate and 20mg/L initial concentration. The Thomas model better described the whole dynamic behaviour of the column rather than the Dose Response and Yoon-Nelson models. Finally, desorption studies indicated that metal-loaded biosorbent could be used after three consecutive sorption, desorption and regeneration cycles by applying a semi-simulated real wastewater.
Ahmed, M.B., Johir, M.A.H., Zhou, J.L., Ngo, H.H., Guo, W. & Sornalingam, K. 2017, 'Photolytic and Photocatalytic Degradation of Organic UV Filters in Contaminated Water', Current Opinion in Green and Sustainable Chemistry.View/Download from: UTS OPUS or Publisher's site
Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Thomaidis, N.S. & Xu, J. 2017, 'Progress in the biological and chemical treatment technologies for emerging contaminant removal from wastewater: A critical review.', Journal of Hazardous Materials, vol. 323, pp. 274-298.View/Download from: UTS OPUS or Publisher's site
This review focuses on the removal of emerging contaminants (ECs) by biological, chemical and hybrid technologies in effluents from wastewater treatment plants (WWTPs). Results showed that endocrine disruption chemicals (EDCs) were better removed by membrane bioreactor (MBR), activated sludge and aeration processes among different biological processes. Surfactants, EDCs and personal care products (PCPs) can be well removed by activated sludge process. Pesticides and pharmaceuticals showed good removal efficiencies by biological activated carbon. Microalgae treatment processes can remove almost all types of ECs to some extent. Other biological processes were found less effective in ECs removal from wastewater. Chemical oxidation processes such as ozonation/H2O2, UV photolysis/H2O2 and photo-Fenton processes can successfully remove up to 100% of pesticides, beta blockers and pharmaceuticals, while EDCs can be better removed by ozonation and UV photocatalysis. Fenton process was found less effective in the removal of any types of ECs. A hybrid system based on ozonation followed by biological activated carbon was found highly efficient in the removal of pesticides, beta blockers and pharmaceuticals. A hybrid ozonation-ultrasound system can remove up to 100% of many pharmaceuticals. Future research directions to enhance the removal of ECs have been elaborated.
Liu, Y., Ngo, H.H., Guo, W., Zhou, J., Peng, L., Wang, D., Chen, X., Sun, J. & Ni, B.J. 2017, 'Optimizing sulfur-driven mixotrophic denitrification process: System performance and nitrous oxide emission', Chemical Engineering Science, vol. 172, pp. 414-422.View/Download from: UTS OPUS or Publisher's site
© 2017 Nitrate contamination of groundwater has been recognized as a significant environmental problem world widely. Sulfur-driven mixotrophic denitrification has been demonstrated as a promising groundwater treatment process, which though plays an important role in nitrous oxide (N 2 O) emissions, significantly contributing to the overall carbon footprint of the system. However, the current process optimizations only focus on nitrate removal and excess sulfate control, with the N 2 O emission being ignored. In this work, an integrated mathematical model was proposed to evaluate the N 2 O emission as well as the excess sulfate production and carbon source utilization in sulfur-driven mixotrophic denitrification process. In this model, autotrophic and heterotrophic denitrifiers use their corresponding electron donors (sulfur and organic matter, respectively) to reduce nitrate to nitrogen gas, with each modeled as three-step denitrification (NO 3 to N 2 via NO 2 and N 2 O) driven by sulfur or organic matter to describe all potential N 2 O accumulation steps. The developed model, employing model parameters previously reported in literature, was successfully validated using N 2 O and sulfate data from two mixotrophic denitrification systems with different initial conditions. Modeling results revealed substantial N 2 O accumulation due to the relatively low autotrophic N 2 O reduction activity as compared to heterotrophic N 2 O reduction activity, explaining the observation that higher carbon source addition resulted in lower N 2 O accumulation in sulfur-driven mixotrophic denitrifying system. Based on the validated model, optimizations of the overall system performance were carried out. Application of the model to simulate long-term operations of sulfur-driven mixotrophic denitrification process indicates that longer sludge retention time reduces N 2 O emission due to better retention of active biomass. High-level total nitrogen removal with significant N 2 O emi...
Liu, Y., Zhang, Y., Zhao, Z., Ngo, H.H., Guo, W., Zhou, J., Peng, L. & Ni, B.-.J. 2017, 'A modeling approach to direct interspecies electron transfer process in anaerobic transformation of ethanol to methane.', Environmental Science and Pollution Research, vol. 24, no. 1, pp. 855-863.View/Download from: UTS OPUS or Publisher's site
Recent studies have shown that direct interspecies electron transfer (DIET) plays an important part in contributing to methane production from anaerobic digestion. However, so far anaerobic digestion models that have been proposed only consider two pathways for methane production, namely, acetoclastic methanogenesis and hydrogenotrophic methanogenesis, via indirect interspecies hydrogen transfer, which lacks an effective way for incorporating DIET into this paradigm. In this work, a new mathematical model is specifically developed to describe DIET process in anaerobic digestion through introducing extracellular electron transfer as a new pathway for methane production, taking anaerobic transformation of ethanol to methane as an example. The developed model was able to successfully predict experimental data on methane dynamics under different experimental conditions, supporting the validity of the developed model. Modeling predictions clearly demonstrated that DIET plays an important role in contributing to overall methane production (up to 33 %) and conductive material (i.e., carbon cloth) addition would significantly promote DIET through increasing ethanol conversion rate and methane production rate. The model developed in this work will potentially enhance our current understanding on syntrophic metabolism via DIET.
MB Ahmed, JunLiang Zhou, Huu Hao Nog, Wenshan Guo, MAH Johir, K. Sornalingram & MS Rahman 2017, 'Chloramphenicol interaction with functionalized biochar in water: sorptive mechanism, molecular imprinting effect and repeatable application', Science of the Total Environment, vol. 609.View/Download from: UTS OPUS or Publisher's site
Biochar and functionalized biochar (fBC-1 and fBC-2) were prepared and applied to remove antibiotic chloramphenicol
from deionized water, lake water and synthetic wastewater. Results showed that chloramphenicol removal
on biochar was pH dependent and maximum sorption occurred at pH 4.0–4.5. The sorption data of
chloramphenicol fitted better with the Langmuir isotherm model than the Freundlich isotherm model with the
maximum Langmuir sorption capacity of 233 M g1 using fBC-2. Chloramphenicol sorption on fBC-2 followed
the trend: deionized water N lake water N synthetic wastewater. The presence of humic acid decreased the
sorption distribution coefficient (Kd) while the presence of low ionic strength and soil in solution increased Kd
value significantly. The mechanism of sorption on fBC mainly involved electron-donor-acceptor (EDA) interactions
at pH b 2.0; formation of charge assisted hydrogen bond (CAHB) and hydrogen bonds in addition to EDA
in the pH 4.0–4.5; and CAHB and EDA interactions at pH N 7.0. Additionally, solvent and thermal regeneration
of fBC-2 for repeatable applications showed excellent sorption of chloramphenicol under the same condition,
due to the creation of a molecular imprinting effect in fBC-2. Consequently, fBC-2 can be applied with excellent
reusability properties to remove chloramphenicol and other similar organic contaminants.
Narottam Saha, M. Safiur Rahman, Ahmed, M., ZHou, Ngo & Guo 2017, 'Industrial metal pollution in water and probabilistic assessment of human health risk', Journal of Environmental Management, vol. 185, pp. 70-78.View/Download from: UTS OPUS or Publisher's site
Concentration of eight heavy metals in surface and groundwater around Dhaka Export Processing Zone
(DEPZ) industrial area were investigated, and the health risk posed to local children and adult residents
via ingestion and dermal contact was evaluated using deterministic and probabilistic approaches. Metal
concentrations (except Cu, Mn, Ni, and Zn) in Bangshi River water were above the drinking water quality
guidelines, while in groundwater were less than the recommended limits. Concentration of metals in
surface water decreased as a function of distance. Estimations of non-carcinogenic health risk for surface
water revealed that mean hazard index (HI) values of As, Cr, Cu, and Pb for combined pathways (i.e.,
ingestion and dermal contact) were >1.0 for both age groups. The estimated risk mainly came from the
ingestion pathway. However, the HI values for all the examined metals in groundwater were <1.0,
indicating no possible human health hazard. Deterministically estimated total cancer risk (TCR) via
Bangshi River water exceeded the acceptable limit of 1 104 for adult and children. Although, probabilistically
estimated 95th percentile values of TCR exceeded the benchmark, mean TCR values were less
than 1 104
. Simulated results showed that 20.13% and 5.43% values of TCR for surface water were
>1 104 for adult and children, respectively. Deterministic and probabilistic estimations of cancer risk
through exposure to groundwater were well below the safety limit. Overall, the population exposed to
Bangshi River water remained at carcinogenic and non-carcinogenic health threat and the risk was
higher for adults. Sensitivity analysis identified exposure duration (ED) and ingestion rate (IR) of water as
the most relevant variables affecting the probabilistic risk estimation model outcome.
Ahmed, M., Guo, W., Zhou, J., Johir, M. & Ngo, H. 2017, 'Competitive sorption affinity of sulfonamides and chloramphenicol antibiotics toward functionalized biochar for water and wastewater treatment', Bioresource Technology.View/Download from: UTS OPUS or Publisher's site
Competitive sorption of sulfamethazine (SMT), sulfamethoxazole (SMX), sulfathiazole (STZ) and chloramphenicol (CP) toward functionalized biochar (fBC) was highly pH dependent with maximum sorption at pH 4.0-4.25. Equilibrium data were well represented by the Langmuir and Freundlich models in the order STZ > SMX > CP > SMT. Kinetics data were slightly better fitted by the pseudo second-order model than pseudo first-order and intra-particle-diffusion models. Maximum sorptive interactions occurred at pH 4.0-4.25 through H-bonds formations for neutral sulfonamides species and through negative charge assisted H-bond (CAHB) formation for CP, in addition to - electron-donor-acceptor (EDA) interactions. EDA was the main mechanism for the sorption of positive sulfonamides species and CP at pH < 2.0. Sorption of negative sulfonamides species and CP at pH > 7.0 was regulated by H-bond formation and proton exchange with water by forming CAHB, respectively. The results suggested fBC to be highly efficient in removing antibiotics mixture.
Ahmed, M., zhou, J., Ngo, H., Guo, W., Johir, M. & Kiressan, S. 2017, 'Nano-Fe0 Immobilized onto Functionalized Biochar Gaining Excellent Stability during Sorption and Reduction of Chloramphenicol via Transforming to Reusable Magnetic Composite', Chemical Engineering Journal, vol. 322, pp. 571-581.View/Download from: UTS OPUS or Publisher's site
The widely used nanosized zero-valent iron (nZVI or nFe0) particles and their composite material lose reductive nature during application, and the stability of transformed composite material for repeatable application is not addressed to date. To shed light on this, nZVI was synthesized from scrap material and immobilized on functionalized biochar (fBC) to prepare nZVI-fBC composite. Comparative study between nZVI and nZVI-fBC composite on the removal of chlorinated antibiotic chloramphenicol from different water types was conducted. The results suggested that nZVI was solely responsible for reduction of chloramphenicol. Whereas nZVI-fBC could be applied once, within a few hours, for the reduction of chloramphenico (29–32.5%) and subsequently sorption (67.5–70.5%) by transforming to a fully magnetic composite (nFe3O4-fBC) gaining stability with synergistic sorption performance. In both cases, two reduction by-products were identified namely 2-chloro-N-[1,3-dihydroxy-1-(4-aminophenyl)propan-2-yl]acetamide (m/z 257) and dechlorinated N-[1,3-dihydroxy-1-(4-aminophenyl)propan-2-yl]acetamide (m/z 223). The complete removal of 3.1 µM L1 of chloramphenicol in different water was faster by nZVI-fBC (12–15 h) than by stable nFe3O4-fBC composite (18 h). Both nZVI-fBC and nFe3O4-fBC composites removed chloramphenicol in the order: deionized water > lake water > synthetic wastewater. nFe3O4-fBC showed excellent reusability after regeneration, with the regenerated nFe3O4-fBC composite (after 6 cycles of application) showing significant performance for methylene blue removal (287 mg g1). Therefore, the transformed nFe3O4-fBC composite is a promising and reusable sorbent for the efficient removal of organic contaminants.
Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Johir, M.A.H. & Sornalingam, K. 2017, 'Single and competitive sorption properties and mechanism of functionalized biochar for removing sulfonamide antibiotics from water', Chemical Engineering Journal, vol. 311, pp. 348-358.View/Download from: UTS OPUS or Publisher's site
© 2016 Elsevier B.V.Single and competitive sorption of ionisable sulphonamides sulfamethazine, sulfamethoxazole and sulfathiazole on functionalized biochar was highly pH dependent. The equilibrium data were well represented by both Langmuir and Freundlich models for single solutes, and by the Langmuir model for competitive solutes. Sorption capacity and distribution coefficient values decreased as sulfathiazole > sulfamethoxazole > sulfamethazine. The sorption capacity of each antibiotic in competitive mode is about three times lower than in single solute sorption. The kinetics data were best described by the pseudo second-order (PSO) model for single solutes, and by PSO and intra-particle diffusion models for competitive solutes. Adsorption mechanism was governed by pore filling through diffusion process. The findings from pH shift, FTIR spectra and Raman band shift showed that sorption of neutral sulfonamide species occurred mainly due to strong H-bonds followed by +- electron-donor-acceptor (EDA), and by Lewis acid-base interaction. Moreover, EDA was the main mechanism for the sorption of positive sulfonamides species. The sorption of negative species was mainly regulated by proton exchange with water forming negative charge assisted H-bond (CAHB), followed by the neutralization of –OH groups by H+ released from functionalized biochar surface; in addition - electron-acceptor-acceptor (EAA) interaction played an important role.
Belhaj, D., Athmouni, K., Jerbi, B., Kallel, M., Ayadi, H. & Zhou, J.L. 2016, 'Estrogenic compounds in Tunisian urban sewage treatment plant: occurrence, removal and ecotoxicological impact of sewage discharge and sludge disposal.', Ecotoxicology (London, England), vol. 25, no. 10, pp. 1849-1857.View/Download from: Publisher's site
The occurrence, fate and ecotoxicological assessment of selected estrogenic compounds were investigated at Tunisian urban sewage treatment plant. The influents, effluents, as well as primary, secondary and dehydrated sludge, were sampled and analyzed for the target estrogens to evaluate their fate. All target compounds were detected in both sewage and sludge with mean concentrations from 0.062 to 0.993g L-1 and from 11.8 to 792.9g kg-1dry weight, respectively. A wide range of removal efficiencies during the treatment processes were observed, from 6.3% for estrone to 76.8% for estriol. Ecotoxicological risk assessment revealed that the highest ecotoxicological risk in sewage effluent and dehydrated sludge was due to 17-estradiol with a risk quotient (RQ) of 4.6 and 181.9, respectively, and 17-ethinylestradiol with RQ of 9.8 and 14.85, respectively. Ecotoxicological risk after sewage discharge and sludge disposal was limited to the presence of 17-estradiol in dehydrated-sludge amended soil with RQ of 1.38. Further control of estrogenic hormones in sewage effluent and sludge is essential before their discharge and application in order to prevent their introduction into the natural environment.
Belhaj, D., Jerbi, B., Medhioub, M., Zhou, J., Kallel, M. & Ayadi, H. 2016, 'Impact of treated urban wastewater for reuse in agriculture on crop response and soil ecotoxicity', Environmental Science and Pollution Research, vol. 23, pp. 15877-15887.View/Download from: UTS OPUS or Publisher's site
© 2015 Springer-Verlag Berlin Heidelberg The scarcity of freshwater resources is a serious problem in arid regions, such as Tunisia, and marginal quality water is gradually being used in agriculture. This study aims to study the impact of treated urban wastewater for reuse in agriculture on the health of soil and food crops. The key findings are that the effluents of Sfax wastewater treatment plant (WWTP) did not meet the relevant guidelines, therefore emitting a range of organic (e.g., up to 90 mg L1 COD and 30 mg L1 BOD5) and inorganic pollutants (e.g., up to 0.5 mg L1 Cu and 0.1 mg L1 Cd) in the receiving aquatic environments. Greenhouse experiments examining the effects of wastewater reuse on food plants such as tomato, lettuce, and radish showed that the treated effluent adversely affected plant growth, photosynthesis, and antioxidant enzyme contents. However, the pollution burden and biological effects on plants were substantially reduced by using a 50 % dilution of treated sewage effluent, suggesting the potential of reusing treated effluent in agriculture so long as appropriate monitoring and control is in place.
Qiang, L., Cheng, J., Yi, J., Rotchell, J.M., Zhu, X. & Zhou, J. 2016, 'Environmental concentration of carbamazepine accelerates fish embryonic development and disturbs larvae behavior', Ecotoxicology, vol. 25, no. 7, pp. 1426-1437.View/Download from: Publisher's site
Environmental pollution caused by pharmaceuticals has been recognized as a major threat to the aquatic ecosystems. Carbamazepine, as the widely prescribed antiepileptic drug, has been frequently detected in the aquatic environment and has created concerns about its potential impacts in the aquatic organisms. The effects of carbamazepine on zebrafish embryos were studied by examining their phenotype, behavior and molecular responses. The results showed that carbamazepine disturbed the normal growth and development of exposed zebrafish embryos and larvae. Upon exposure to carbamazepine at 1 g/L, the hatching rate, body length, swim bladder appearance and yolk sac absorption rate were significantly increased. Embryos in treatment groups were more sensitive to touch and light stimulation. At molecular level, exposure to an environmentally relevant concentration (1 g/L) of carbamazepine disturbed the expression pattern of neural-related genes of zebrafish embryos and larvae. This study suggests that the exposure of fish embryo to antiepileptic drugs, at environmentally relevant concentrations, affects their early development and impairs their behavior. Such impacts may have future repercussions by affecting fish population structure.
Xu, J., Cao, Z., Liu, X., Zhao, H., Xiao, X., Wu, J., Xu, X. & Zhou, J.L. 2016, 'Preparation of functionalized Pd/Fe-Fe3O4@MWCNTs nanomaterials for aqueous 2,4-dichlorophenol removal: Interactions, influence factors, and kinetics.', Journal of hazardous materials, vol. 317, pp. 656-666.View/Download from: UTS OPUS or Publisher's site
Magnetic multi-walled carbon nanotubes (MWCNTs) were prepared to support Pd/Fe nanoparticles, inhibit the aggregation and passivation, and achieve magnetic separation to avoid the environmental risk of nanoparticles. Rapid adsorption of initial contaminant, steady dechlorination, and gradual desorption of final product was observed. The micromorphology, chemical structure, and components of the nanohybrids were comprehensively characterized by a series of analysis technologies, such as EDX, XRD, SEM, TEM, and XPS. The interactions between the nanohybrids compositions were discussed according to the characterization and experimental data. The whole insight of 2,4-dichlorophenol (2,4-DCP) adsorption- dechlorination-desorption was studied in detail, including the pathways, influence factors, dechlorination kinetics and selectivity. Weak acidity (pH=5.0 and 6.5) favored the 2,4-DCP removal. Satisfactory reactivity of the Pd/Fe-Fe3O4@MWCNTs nanohybrids was observed in five consecutive runs, and 99.2%, 89.6%, 92.1%, 99.8%, and 99.9% of 2,4-DCP was removed, respectively. Most of the final product (phenol) was steadily desorbed to the liquid phase, resulted in the re-exposure of active sites on the nanohybrids and maintained a longer activity.
Xu, J., Liu, X., Lowry, G.V., Cao, Z., Zhao, H., Zhou, J.L. & Xu, X. 2016, 'Dechlorination Mechanism of 2,4-Dichlorophenol by Magnetic MWCNTs Supported Pd/Fe Nanohybrids: Rapid Adsorption, Gradual Dechlorination, and Desorption of Phenol.', ACS applied materials & interfaces, vol. 8, no. 11, pp. 7333-7342.View/Download from: Publisher's site
2,4-dichlorophenol was effectively removed from water using magnetic Pd/Fe nanoparticles supported on multiwalled carbon nanotubes (MWCNTs). The adsorption kinetics, isotherms, and energy for 2,4-dichlorophenol and its partially (4-chlorophenol, 2-chlorophenol) and completely (phenol) dechlorinated products are presented and discussed. The adsorption capacity was 2,4-dichlorophenol > 4-chlorophenol > 2-chlorophenol > phenol for MWCNTs. MWCNTs-Fe3O4-Pd/Fe nanohybrids provided rapid adsorption, gradual dechlorination, and final desorption of phenol, which is attractive as a remediation technology. Over 82.7% of the phenol was desorbed and released to the aqueous phase after 72 h due to its low adsorption capacity, leaving the majority of active sites available on the surface of MWCNTs-Fe3O4-Pd/Fe. The nanohybrids maintained high activity in five consecutive in situ experiments, and they were retrievable using magnetic separation. MWCNTs-Fe3O4-Pd/Fe nanohybrids outperform unsupported Pd/Fe nanoparticles, which were difficult to retrieve, and were easily passivated and aggregated.
Sornalingam, K., McDonagh, A. & Zhou, J.L. 2016, 'Photodegradation of estrogenic endocrine disrupting steroidal hormones in aqueous systems: Progress and future challenges.', The Science of the total environment, vol. 550, pp. 209-224.View/Download from: UTS OPUS or Publisher's site
This article reviews different photodegradation technologies used for the removal of four endocrine disrupting chemicals (EDCs): estrone (E1), 17-estradiol (E2), estriol (E3) and 17-ethinylestradiol (EE2). The degradation efficiency is greater under UV than visible light; and increases with light intensity up to when mass transfer becomes the rate limiting step. Substantial rates are observed in the environmentally relevant range of pH7-8, though higher rates are obtained for pH above the pKa (~10.4) of the EDCs. The effects of dissolved organic matter (DOM) on EDC photodegradation are complex with both positive and negative impacts being reported. TiO2 remains the best catalyst due to its superior activity, chemical and photo stability, cheap commercial availability, capacity to function at ambient conditions and low toxicity. The optimum TiO2 loading is 0.05-1gl(-1), while higher loadings have negative impact on EDC removal. The suspended catalysts prove to be more efficient in photocatalysis compared to the immobilised catalysts, while the latter are considered more suitable for commercial scale applications. Photodegradation mostly follows 1st or pseudo 1st order kinetics. Photodegradation typically eradicates or moderates estrogenic activity, though some intermediates are found to exhibit higher estrogenicity than the parent EDCs; the persistence of estrogenic activity is mainly attributed to the presence of the phenolic moiety in intermediates.
Biochars (BCs) are widely produced and used for the remediation of environmental contaminants as bio-sorbents. In this review, statistical analysis of different BC physico–chemical properties was conducted. It was observed that woody materials are the most suitable for preparing BCs, among many other potential raw materials such as food wastes and agricultural materials. Currently BCs are produced through a variety of thermal treatment processes between 300 and 900 °C, among which slow pyrolysis is widely used due to its moderate operating conditions and optimization of BC yields. Hydrothermal carbonisation (HTC) is also an effective approach for BC production under certain conditions. As pyrolysis temperature is increased, the carbon content, ash content, surface area, and pore volume tend to be increased while the yield, hydrogen, oxygen, nitrogen content, and H/C and O/C molar ratios tend to decrease. The economic feasibility of BCs depends on a range of factors from raw material price to efficient production technologies. Thus, the overall cost equation of a pilot BC production plant together with the cost equation for BC regeneration has been proposed. The future research directions of BCs are also elaborated
Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W. & Chen, M. 2016, 'Progress in the preparation and application of modified biochar for improved contaminant removal from water and wastewater', BIORESOURCE TECHNOLOGY, vol. 214, pp. 836-851.View/Download from: UTS OPUS or Publisher's site
Khan, M.A., Ngo, H.H., Guo, W.S., Liu, Y.W., Zhou, J.L., Zhang, J., Liang, S., Ni, B.J., Zhang, X.B. & Wang, J. 2016, 'Comparing the value of bioproducts from different stages of anaerobic membrane bioreactors', Bioresource Technology, vol. 214, pp. 816-825.View/Download from: UTS OPUS or Publisher's site
Abstract The anaerobic digestion process in anaerobic membrane bioreactors is an effective way for waste management, energy sustainability and pollution control in the environment. This digestion process basically involves the production of volatile fatty acids and biohydrogen as intermediate products and methane as a final product. This paper compares the value of bioproducts from different stages of anaerobic membrane bioreactors through a thorough assessment. The value was assessed in terms of technical feasibility, economic assessment, environmental impact and impact on society. Even though the current research objective is more inclined to optimize the production of methane, the intermediate products could also be considered as economically attractive and environment friendly options. Hence, this is the first review study to correlate the idea into an anaerobic membrane bioreactor which is expected to guide future research pathways regarding anaerobic process and its bioproducts.
Belhaj, D., Baccar, R., Jaabiri, I., Bouzid, J., Kallel, M., Ayadi, H. & Zhou, J.L. 2015, 'Fate of selected estrogenic hormones in an urban sewage treatment plant in Tunisia (North Africa).', The Science of the total environment, vol. 505, pp. 154-160.View/Download from: UTS OPUS or Publisher's site
Estrogenic compounds have been monitored for one year at an urban sewage treatment plant (STP) located in Tunisia, to evaluate their fate and seasonal variations. The concentrations of these compounds were determined in both wastewater and sludge phases by gas chromatography coupled with mass spectrometry (GC-MS). Results showed that the highest removal of all estrogens (80%) was observed in summer. Mass balance analysis revealed that biodegradation was the predominant removal mechanism. Moreover, the results showed that the removal efficiency of the studied emerging micropollutants and their concentrations in the solid phase of return sludge were much higher in winter and spring than in summer and autumn. These findings were closely related to microbial activity and the concentration of mixed liquor suspended solids (MLSSs). Finally, the findings can be used to help with the modifications that could be implemented in that STP for the improved removal of estrogenic contaminants.
Abdolali, A., Ngo, H.H., Guo, W., Zhou, J.L., Du, B., Wei, Q., Wang, X.C. & Nguyen, P.D. 2015, 'Characterization of a multi-metal binding biosorbent: Chemical modification and desorption studies', BIORESOURCE TECHNOLOGY, vol. 193, pp. 477-487.View/Download from: UTS OPUS or Publisher's site
Ahmed, M.B., Zhou, J.L., Ngo, H.H. & Guo, W. 2015, 'Adsorptive removal of antibiotics from water and wastewater: Progress and challenges', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 532, pp. 112-126.View/Download from: UTS OPUS or Publisher's site
Vo, T., Ngo, H., Guo, W., Zhou, J., Listowski, A., Du, B., Wei, Q. & Bui, X. 2015, 'Stormwater quality management in rail transportation — Past, present and future', Science of the Total Environment, vol. 512-513, pp. 353-363.View/Download from: UTS OPUS or Publisher's site
Railways currently play an important role in sustainable transportation systems, owing to their substantial carrying capacity, environmental friendliness and land-saving advantages. Although total pollutant emissions from railway systems are far less than that of automobile vehicles, the pollution from railway operations should not be underestimated. To date, both scientific and practical papers dealing with stormwater management for rail tracks have solely focused on its drainage function. Unlike roadway transport, the potential of stormwater pollution from railway operations is currently mishandled. There have been very few studies into the impact of its operations on water quality. Hence, upon the realisation on the significance of nonpoint source pollution, stormwater management priorities should have been re-evaluated. This paper provides an examination of past and current practices of stormwater management in the railway industry, potential sources of stormwater pollution, obstacles faced in stormwater management and concludes with strategies for future management directions.
Zhou, J. 2014, 'Occurrence and removal of steroidal estrogens in Centre Eastern Tunisia municipal sewage treatment plant', Desalination and Water Treatment, vol. 52, no. 10-12, pp. 2330-2339.View/Download from: UTS OPUS or Publisher's site
Occurrence and removal efficiencies of both natural estrogens, estrone (E1), 17-estradiol (E2) and estriol (E3), and a synthetic estrogen, 17a-ethinylestradiol (EE2), were investigated in sewage treatment plant in Centre Eastern Tunisia employing simple activated sludge process. Concentrations of target estrogens were determined in both wastewater and sludge phases by gas chromatography coupled with mass spectrometer. Among the estrogens studied, E3 was found as the dominant compound detected in wastewater samples with average concentration up to 300?±?4?ng/L in influent and up to 36?±?2 in effluent. High aqueous phase removals (>85%) were achieved for E3, while only low to moderate removals for E1, E2, and EE2 (<75%). Based on the mass balance analysis, sorption onto sludge played a dominant role in the removal of estrogens in warm season, especially for E1 and E2 (69.5 and 66.3%, respectively), while biological degradation played a significant role in hot season (61%).
Zhou, J. & Broodbank, N. 2014, 'Sediment-water interactions of pharmaceutical residues in the river environment', Water Research, vol. 48, no. 1, pp. 61-70.View/Download from: UTS OPUS or Publisher's site
To assess the environmental fate and risks of pharmaceuticals, the determination of their distributions between sediment and water is crucial as a controlling process. In this paper, the concentrations of 9 selected pharmaceuticals were determined in water and sediment samples from the River Medway, Kent, UK between December 2009 and December 2010. In the water phase, there was a spatial variation of concentration with the highest concentrations being detected in the sewage outfall, indicating it being an important point source in the river. In terms of seasonal variations, the highest concentrations (13878 ng L-1) were detected in June 2010. In the surface sediment phase, the highest concentrations (5.333.6 ng g-1 dry weight) were observed at the sewage outfall, although in February 2010 the highest concentrations were detected downstream of the sewage outfall indicating a delayed response in sediment accumulation of pharmaceuticals in relation to the water phase. The partition coefficient of pharmaceuticals between surface sediment and water was variable, reflecting a dynamic process of sediment-water interaction and the varying nature of sediments. Overall the partition coefficient was shown to decrease with an increase in suspended sediment concentration. The organic carbon normalized partition coefficient of the pharmaceuticals was shown to be positively related to their molecular weight (MW), suggesting that sediment-water interactions were partly a partition process favoring large molecules.
Nguyen, T., Ngo, H., Guo, W., Zhou, J., Wang, J., Liang, H. & Li, G. 2014, 'Phosphorus elimination from aqueous solution using 'zirconium loaded okara' as a biosorbent', Bioresource Technology, vol. 170, pp. 30-37.View/Download from: UTS OPUS or Publisher's site
This work deals with the capture of phosphorus from aqueous solutions by biosorption onto zirconium loaded okara (ZLO). The batch-mode experiments were conducted to examine the effect of pH, biosorbent dose, initial phosphorus concentration, contact time, and temperature on the process. It was found that, the adsorption was most favored in the pH range of 26. The optimal doses for the adsorption, at initial phosphorus concentrations of 5, 10, 25, 50 mg/L were 2, 3, 7, 10 g/L, respectively. The maximum adsorption capacity of ZLO was approximately 44.13 mg PO4/g at 298 K. The phosphate removal was rapid, reaching 95% in 30 min. Freundlich model best fitted the equilibrium data, while Pseudo-second order model satisfactorily described the kinetic results. Thermodynamic analysis revealed feasible, spontaneous, and endothermic nature of the process. The research would be beneficial for developing a promising, eco-friendly phosphorus biosorbent from a plentiful AWB okara.
Zhou, J., Siddiqui, E., Ngo, H. & Guo, W. 2014, 'Estimation of uncertainty in the sampling and analysis of polychlorinated biphenyls and polycyclic aromatic hydrocarbons from contaminated soil in Brighton, UK', The Science of the Total Environment, vol. 497-498, pp. 163-171.View/Download from: UTS OPUS or Publisher's site
The heterogeneity of environmental samples is increasingly recognised, yet rarely examined in organic contamination investigations. In this study soil samples from an ex-landfill site in Brighton, UK were analysed for polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH) contamination by using a balanced sampling protocol. The analytical technique of gas chromatographymass spectrometry was found to be fit for purpose by the use of duplicate samples and the statistical analysis of variances, as well as of certified reference materials. The sampling uncertaintywas found to significantly overweigh the analytical uncertainty, by a factor of 3 and 6 for PCBs and PAHs, respectively. The soil samples showed a general trend of PCB concentration that was under the recommended target level of 20 ng/g dry weight. It is possible that one site alongside the main road may exceed the 20 ng/g target level, after taking into consideration the overall measurement uncertainty (70.8%). The PAH contamination was more severe, with seven sites potentially exceeding the effect-range medium concentrations. The soil samples with relatively high PCB and PAH concentrations were all taken from the grass verge, which also had the highest soil organic carbon content. The measurement uncertainty which was largely due to sampling can be reduced by sampling at a high resolution spacing of 17 m,which is recommended in future field investigations of soil organic contamination.
Chekli, L., Phuntsho, S., Tijing, L.D., Zhou, J.L., Kim, J.-.H. & Shon, H.K. 2014, 'Stability of Fe-oxide nanoparticles coated with natural organic matter under relevant environmental conditions', Water Science & Technology, vol. 70, no. 12, pp. 2040-2046.View/Download from: UTS OPUS or Publisher's site
Manufactured nanoparticles (MNPs) are increasingly released into the environment and thus research on their fate and behaviour in complex environmental samples is urgently needed. The fate of MNPs in the aquatic environment will mainly depend on the physico-chemical characteristics of the medium. The presence and concentration of natural organic matter (NOM) will play a significant role on the stability of MNPs by either decreasing or exacerbating the aggregation phenomenon. In this study, we firstly investigated the effect of NOM concentration on the aggregation behaviour of manufactured Fe-oxide nanoparticles. Then, the stability of the coated nanoparticles was assessed under relevant environmental conditions. Flow field-flow fractionation, an emerging method which is gaining popularity in the field of nanotechnology, has been employed and results have been compared to another size-measurement technique to provide increased confidence in the outcomes. Results showed enhanced stability when the nanoparticles are coated with NOM, which was due to electrosteric stabilisation. However, the presence of divalent cations, even at low concentration (i.e. less than 1 mM) was found to induce aggregation of NOM-coated nanoparticles via bridging mechanisms between NOM and Ca2+
Vo, Ngo, H., Guo, W., Zhou, J., Nguyen, P.D., Listowski, A. & Wang, X.C. 2014, 'A mini-review on the impacts of climate change on wastewater reclamation and reuse', The Science of the Total Environment, vol. 494-495, pp. 9-17.View/Download from: UTS OPUS or Publisher's site
To tackle current water insecurity concerns, wastewater reclamation and reuse have appeared as a promising candidate to conserve the valuable fresh water sources while increasing the efficiency of material utilization. Climate change, nevertheless, poses both opportunities and threats to the wastewater reclamation industry. Whereas it elevates the social perception on water-related issues and fosters an emerging water-reuse market, climate change simultaneously presents adverse impacts on the water reclamation scheme, either directly or indirectly. These effects were studied fragmentally in separate realms. Hence, this paper aims to link these studies for providing a thorough understanding about the consequences of the climate change on the wastewater reclamation and reuse. It initially summarizes contemporary treatment processes and their reuse purposes before carrying out a systematic analysis of available findings.
Bedi, J.S., Lester, D.W., Fang, Y.X., Turner, J.F.C., Zhou, J., Alfadul, S.M., Perry, C. & Chen, Q. 2013, 'Electrospinning of poly(methyl methacrylate) nanofibers in a pump-free process', Journal of Polymer Engineering, vol. 33, no. 5, pp. 453-461.View/Download from: UTS OPUS or Publisher's site
The effects of processing parameters, including solution concentration, viscosity, nozzle diameter, voltage bias and the nozzle to collector distance, on the morpho logy and diameters of poly(methyl methacrylate) (PMMA) fibers have been systematically investigated, using a unique pump-free electrospinning method. For PMMA solution concentrations less than the critical entanglement concentration, c e, prolate spheroidshaped droplets or beads with fibers were formed, whereas at concentrations above c e, good quality beadfree fibers were formed. Quantitative analysis revealed a linear dependence between the solution viscosity and fiber diameter. Larger fiber diameters were achieved by increasing the nozzle diameter and voltage bias. Increasing the bias voltage has the additional effect of broadening the diameter distribution, as a result of splaying and splitting. By contrast, when the strength of the electrical field was reduced by increasing the distance between the nozzle and collector, the overall fiber dia meter was reduced.
Lee, J., Lee, Y., Zhou, J., Oh, S. & Kim, S. 2012, 'Changes in the sorption and rate of 17-estradiol biodegradation by dissolved organic matter collected from different water sources', Journal of Environmental Monitoring, vol. 14, no. 1, pp. 543-551.View/Download from: UTS OPUS or Publisher's site
The potential biodegradation and subsequent transformation of 17-estradiol (E2) to estrone (E1) were examined in the presence of various dissolved organic matter (DOM) isolated from effluent, river and lake waters. In addition, estrogenicity was estimated in association with the removal of E2 via its sorption onto DOM and biodegradation. The more biodegradable lake-derived DOM promoted more extensive transformation of E2 into E1 than the effluent organic matter through a biodegradation process. Overall, under all conditions, biodegradation dominated the removal of E2 in water. The increased dissolved organic carbon (DOC) concentrations in river and lake-derived DOM (e.g. 6.5 mg C L(-1)) reduced the removal of E2 by decreasing its biodegradation due to the moderate sorption of E2 onto DOM. The effluent organic matter showed greater removal of E2 via biodegradation, as well as significantly high sorption. This was associated with a large amount of hydrophobic fulvic acid (FA)- and humic acid (HA)-like organic components, as shown by the small increase in the specific UV absorbance at 254 nm (SUVA(254)). An increase in the DOC concentration reduced the removal of E2, resulting in high estrogenicity. The present study suggests that both organic composition and DOC concentration influenced the removal of E2 and, therefore, should be fully considered when assessing estrogenicity and its impacts on the aquatic environment.
Zhou, J., Maskaoui, K. & Lufadeju, A. 2012, 'Optimization of antibiotic analysis in water by solid-phase extraction and high performance liquid chromatography-mass spectrometry/mass spectrometry', Analytica Chimica Acta, vol. 731, no. 1, pp. 32-39.View/Download from: UTS OPUS or Publisher's site
This paper describes the development of an optimized method based on solid-phase extraction (SPE) followed by liquid chromatographyelectrospray ionization tandem mass spectrometry (LCMS/MS) for the simultaneous analysis of ten antibiotic compounds including tetracyclines, sulfonamides, macrolides and quinolones. LCMS/MS sensitivity has been optimized by alterations to both LC and MS operations. Of the two high resolution columns tested, Waters Symmetry C18 endcapped and Agilent Zorbax Bonus-RP, the latter was found to show better performance in producing sharp peaks and clear separation for most of the target compounds. Optimization of the MS fragmentation collision and cone energy enhanced the peak areas of the target analytes. The recovery of the target compounds from water samples was most efficient on Waters Oasis HLB SPE cartridge, while methanol was shown to be the most suitable solvent for desorbing the compounds from SPE. In addition, acidification of samples prior to SPE was shown to enhance the recovery of the compounds. To ensure a satisfactory recovery, the flow rate through SPE should be maintained at =10 mL min-1. The method was successfully applied to the analysis of antibiotics from environmental water samples, with concentrations being
Zhou, Q., Diao, C., Sun, Y. & Zhou, J. 2012, 'Tolerance, uptake and removal of nitrobenzene by a newly-found remediation species Mirabilis jalapa L', Chemosphere, vol. 86, no. 10, pp. 994-1000.View/Download from: UTS OPUS or Publisher's site
The growth, photosynthesis rate, and ultrastructure of Mirabilis jalapa L. as a newly-found remediation species under stress of nitrobenzene (NB) and its uptake and removal of NB by the plants were investigated. The results showed that M. jalapa plants could endure contaminated soils by lower than 10.0 mg NB kg-1 because there was no decrease in the total length of the plant roots, the maximum length of the hypocotyle, the length of the first seminal root, the height of the shoots and the dry biomass of the seedlings as well as the photosynthesis rate of the plants compared with those in the control. In particular, the growth of the plants could be significantly (P < 0.01) enhanced by 0.1 mg NB kg-1 under unautoclaved and autoclaved soils. Ultrastructural observations on leaf cells of the plants found that these cells had smooth, clean and continuous cell membranes and cell walls, indicating that there was no obvious damage by NB in comparison with those in the control. Although the absorption of NB in shoots and roots of M. jalapa was weak, plant-promoted biodegradation of NB was considerable and the dominant contribution in the removal of NB from contaminated soils, suggesting the feasibility of M. jalapa applied to phytoremediation of NB contaminated soils
Grover, D.P., Balaam, J.L., Pacitto, S., Readman, J.W., White, S. & Zhou, J. 2011, 'Endocrine disrupting activities in sewage effluent and river water determined by chemical analysis and in vitro assay in the context of granular activated carbon upgrade', Chemosphere, vol. 84, no. 10, pp. 1512-1520.View/Download from: UTS OPUS or Publisher's site
As part of endocrine disruption in catchments (EDCAT) programme, this work aims to assess the temporal and spatial variations of endocrine disrupting chemicals (EDCs) in River Ray, before and after the commissioning of a full-scale granular activated carbon (GAC) plant at a sewage treatment works (STW). Through spot and passive sampling from effluent and river sites, estrogenic and anti-androgenic activities were determined by chemical analysis and in vitro bio-assay. A correlation was found between chemical analyses of the most potent estrogens (estrone (E1), 17-estradiol (E2), 17a-ethinylestradiol (EE2)) and yeast estrogen screen (YES) measurement, both showing clearly a reduction in estrogenic activity after the commissioning of the GAC plant at the STW. During the study period, the annual average concentrations of E1, E2 and EE2 had decreased from 3.5 ng L-1, 3.1 ng L-1 and 0.5 ng L-1 to below their limit of detection (LOD), respectively, with a concentration reduction of at least 91%, 81% and 60%. Annual mean estrogenic activity measured by YES of spot samples varied from 1.9 ng L-1 to 0.4 ng L-1 E2 equivalent between 2006 and 2008 representing a 79% reduction. Similarly, anti-androgenic activity measured by yeast anti-androgen screen (anti-YAS) of spot samples was reduced from 148.8 to 22.4 µg flutamide L-1, or by 85%. YES and anti-YAS values were related to each other, suggesting co-existence of both types of activities from chemical mixtures in environmental samples. The findings confirm the effectiveness of a full-scale GAC in removing both estrogenic and anti-androgenic activities from sewage effluent.
Grover, D.P., Zhou, J., Frickers, P.E. & Readman, J.W. 2011, 'Improved removal of estrogenic and pharmaceutical compounds in sewage effluent by full scale granular activated carbon: impact on receiving river water', Journal of Hazardous Materials, vol. 185, no. 2-3, pp. 1005-1011.View/Download from: UTS OPUS or Publisher's site
Sewage effluents are widely recognised as the main source of emerging contaminants, such as endocrine disrupting chemicals (EDCs) and pharmaceuticals in surface waters. A full-scale granular activated carbon (GAC) plant has been installed as an advanced technology for the removal of these contaminants, in a major sewage treatment works (STW) in South-West England as part of the UK National Demonstration Programme for EDCs. This study presented for the first time, an assessment of the impact of a recently commissioned, post-tertiary GAC plant in the removal of emerging contaminants in a working STW. Through regular sampling followed by solid-phase extraction and analysis by liquid chromatographytandem mass spectrometry (LCMS/MS), a significant reduction in the concentrations of steroidal estrogens was observed (>4364%). In addition, significant reductions were observed for many of the pharmaceutical compounds such as mebeverine (8499%), although the reduction was less dramatic for some of the more widely used pharmaceuticals analysed, including carbamazepine and propranolol (1723%).
Lee, J., Zhou, J. & Kim, S. 2011, 'Effects of biodegradation and sorption by humic acid on the estrogenicity of 17 beta-estradiol', Chemosphere, vol. 85, no. 8, pp. 1383-1389.View/Download from: UTS OPUS or Publisher's site
The removal of 17 beta-estradiol (E2) by biodegradation and sorption onto humic acid (HA) was examined at various HA concentrations. Subsequently, estrogenicity associated with E2 removal was estimated using E-screen bioassay. Results showed that E2 biodegradation and its subsequent transformation to estrone (E1) were significantly reduced with increasing HA concentration. In addition, the presence of nutrients enhanced the biodegradation of E2. Overall, E2 biodegradation was the dominating contributor to its removal, which demonstrated a significantly negative correlation with E2 sorption at various HA concentrations. The sorption of E2 by HA was significantly enhanced with increasing HA concentration. Estrogenicity associated with residual E2 showed that there existed a significant difference among various HA concentrations, with the lowest value in the absence of HA. The findings suggest that the presence of HA and nutrients in natural waters should be considered in assessing estrogenicity of environmental samples due to complex sorption and biodegradation processes
Yang, Y., Fu, J., Peng, H., Hou, L., Liu, M. & Zhou, J. 2011, 'Occurrence and phase distribution of selected pharmaceuticals in the Yangtze Estuary and its coastal zone', Journal of Hazardous Materials, vol. 190, no. 1-3, pp. 588-596.View/Download from: UTS OPUS or Publisher's site
The occurrence and geochemical behavior of nine pharmaceutical compounds were investigated along the Yangtze River Estuary and its coastal area, by sampling and analysis of pharmaceuticals in sediment, suspended particulate matter (SPM), colloidal and soluble phases. In addition, the impact of sewage input was examined by sampling from sewage treatment plants (STP) effluent and its upstream and downstream in the Yangtze River. Although at relatively low concentrations in SPM and sediments, several pharmaceuticals were found at elevated concentration in filtered water samples from STP-affected sites. STP is therefore an important input of pharmaceuticals in the study area. Colloidal phase was further separated from bulk water samples using cross-flow ultrafiltration (CFUF), confirming it being an effective sorbent for pharmaceuticals with high sorption capacity which are 24 orders of magnitude higher than SPM. Moreover, mass balance calculations showed that significant percentages of selected pharmaceutical compounds were associated with aquatic colloids, indicating colloids as a reservoir for these contaminants in the Yangtze estuarine system.
Atkins, A., Bignal, K.L., Zhou, J. & Cazier, F. 2010, 'Profiles of polycyclic aromatic hydrocarbons and polychlorinated biphenyls from wood pellet combustion', Chemosphere, vol. 78, no. 11, pp. 1385-1392.View/Download from: UTS OPUS or Publisher's site
An investigation was made into the emissions of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) as well as inorganic gases (e.g. CO) from a wood fired combustion boiler using wood pellets, under two different boiler operating modes. Levels of total PAHs varied from 6.4 and 154 µg m-3, and were found to be dominating in the gas phase (>80%), regardless of pellet type and boiler operating mode. In addition to this, PAH concentrations were higher in slumber mode than in full flame, and increased with the moisture content of pellets, consistent with the lower combustion efficiency in slumber mode (58.664.3%) than in full flame (74.482.3%). PAHs in the gas phase comprised mainly of low molecular mass compounds, while PAHs in the particulate phase were mostly composed of high molecular mass compounds, consistent with the physicochemical properties of such compounds. In comparison to PAHs, significantly lower concentrations of PCBs (a maximum of 2.5 µg m-3) were released from pellet combustion, consistent with the virgin nature of the pellets. The PCBs in both the gas and particulate phases were dominated by hexachlorinated congeners, although congeners with more chlorine substitution were more abundant in the particulate phase than in gas phase. Significant relationships were established between CO and organic pollutants, and between PAHs and PCBs, which are useful tools for prediction purposes.
Balaam, J.L., Grover, D.P., Johnson, A.C., Jurgens, M., Readman, J.W., Smith, A.C., Williams, R., White, S. & Zhou, J. 2010, 'The use of modelling to predict levels of estrogens in a river catchment: how does modelled data compare with chemical analysis and in vitro yeast assay results?', The Science of the Total Environment, vol. 408, no. 20, pp. 4826-4832.View/Download from: UTS OPUS or Publisher's site
Effluent discharges at Rodbourne sewage treatment works (STWs) were assessed using chemical and in vitro biological analysis as well as modelling predictions. Results showed that Rodbourne STW discharged less estrone (E1) than expected, but similar 17-estradiol (E2) and 17a-ethinyl estradiol (EE2) to those predicted by a widely cited effluent prediction model. The Exposure Analysis Modelling System (EXAMS) model was set up using measured effluent concentrations as its starting point to predict estrogen concentrations along a 10 km length of the receiving water of the River Ray. The model adequately simulated estrogen concentrations along the river when compared to July 2007 measured data. The model predicted combined estrogen equivalents in reasonable agreement with estrogenicity as measured by passive sampler (POCIS) extracts using the yeast estrogen screen. Using gauged mean flow values for 2007 the model indicated that the most important determinand for estrogen exposure in the Ray was not season, but proximity to the Rodbourne effluent. Thus, fish in the first 3 km downstream of Rodbourne were typically exposed to two or even three times more estrogens than those living 710 km further downstream. The modelling indicated that, assuming the effluent estrogen concentrations measured in February 2008 were typical, throughout the year the whole length of the Ray downstream of Rodbourne would be estrogenic, i.e. exceeding the 1 ng/L E2 equivalent threshold for endocrine disruption.
Maskaoui, K. & Zhou, J. 2010, 'Colloids as a sink for certain pharmaceutical in the aquatic environment', Environmental Science and Pollution Research, vol. 17, no. 4, pp. 898-907.View/Download from: UTS OPUS or Publisher's site
The occurrence and fate of pharmaceuticals in the aquatic environment is recognized as one of the emerging issues in environmental chemistry and as a matter of public concern. Existing data tend to focus on the concentrations of pharmaceuticals in the aqueous phase, with limited studies on their concentrations in particulate phase such as sediments. Furthermore, current water quality monitoring does not differentiate between soluble and colloidal phases in water samples, hindering our understanding of the bioavailability and bioaccumulation of pharmaceuticals in aquatic organisms. In this study, an investigation was conducted into the concentrations and phase association (soluble, colloidal, suspended particulate matter or SPM) of selected pharmaceuticals (propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid) in river water, effluents from sewage treatment works (STW), and groundwater in the UK
Grover, D.P., Zhang, Z., Readman, J.W. & Zhou, J. 2009, 'A comparison of three analytical techniques for the measurement of steroidal estrogens in environmental water samples', Talanta, vol. 78, no. 3, pp. 1204-1210.View/Download from: UTS OPUS or Publisher's site
Research into the analysis and monitoring of steroidal estrogens has grown significantly over the last decade, resulting in the emergence of a range of applicable techniques. In this study, three popular techniques, gas chromatographymass spectrometry (GCMS), gas chromatographytandem mass spectrometry (GCMSMS) and liquid chromatographytandem mass spectrometry (LCMSMS) for the analysis of three highly potent steroidal estrogens in the aquatic environment have been compared. It has been observed that overall, the three techniques appear comparable in generating similar estrogen concentrations for river and effluent samples. Of the three techniques, the GCMS technique is the simplest to operate, but fails to detect the estrogens at the lower-end of environmentally relevant concentrations. The tandem MS techniques are more selective than MS, and therefore able to detect lower concentration levels of the three steroidal estrogens of interest. However, the LCMSMS technique is more susceptible to matrix interferences for the analysis of samples, resulting in a reduction of the signal-to-noise ratio and a subsequent reduction in reliability and stability compared to GCMSMS. With the GCMSMS technique offering increased selectivity, the lowest limits of detection, and no false positive identification, it is recommended to be the preferred analytical technique for routine analysis of estrogens in environmental water samples.
Hibberd, A., Maskaoui, K., Zhang, Z. & Zhou, J. 2009, 'An improved method for the simultaneous analysis of phenolic and steroidal estrogens in water and sediment', Talanta, vol. 77, no. 4, pp. 1315-1321.View/Download from: UTS OPUS or Publisher's site
This paper describes an improved method for the extraction and analysis of seven endocrine disrupting chemicals with wide-ranging polarities from water and sediments using gas chromatographytandem mass spectrometry (GCMS/MS). The analytes were 4-tert-octylphenol, 4-nonylphenol, bisphenol A, estrone, 17-estradiol, 17a-ethynylestradiol and 16a-hydroxyestrone. The optimised GCMS/MS method produces increased selectivity and sensitivity compared to GCMS, with limit of detection ranging from 0.01 to 0.49 ng L-1 in water and from 0.05 to 0.14 ng g-1 in sediment. Extraction from aqueous samples was performed by solid-phase extraction (SPE) and from sediment samples by microwave-assisted extraction (MAE). The improved method for the clean-up of sediment extracts carried out by SPE enhanced EDC recovery (86102%) while reducing matrix interference and sample drying time. Derivatisation of final sample extracts was achieved using N,O-bis(trimethylsilyl)trifluoroacetamide and pyridine, and their stability was enhanced by reconstituting the derivatised extracts with hexane. The method was validated by spiking experiments which showed good recovery and reproducibility. The method was applied to samples taken from the Medway estuary in Kent, UK, where non-conservative behaviour of EDCs was demonstrated.
Wu, D., Liu, X., Wang, L., Wang, L., Xu, M., Sun, T., Yang, Z. & Zhou, J. 2009, 'QSARs on the depuration rate constants of polycyclic aromatic hydrocarbons in Elliptio complanata', QSAR and Combinatorial Science, vol. 28, no. 5, pp. 537-541.View/Download from: Publisher's site
Using quantum chemical descriptors and partial least squares (PLS) regression, a quantitative structure-activity relationships (QSARs) model was developed to predict the depuration rate constants (k d ) of polycyclic aromatic hydrocarbons (PAHs) for mussels, Elliptio complanata (log k d =-2.1406±0.6013DE-2.0767 10 -3 M w -0.201 E HOMO ). With a high cumulative cross-validated regression coefficient value (Q cum 2 ) of 0.927 and low standard deviation (SD) of 0.065, the model obtained by the training set shows a good predictive ability, and it is validated to be robust by predicting the test set. Among 20 quantum chemical descriptors, the dielectric energy (DE), the molecular weight (M w ), and the highest occupied molecular orbital energy (E HOMO ) are the key descriptors governing the logk d values in the model. Increase in the DE or decrease in the M w values leads to the increase in logk d , indicating the van der Waals interactions and steric hindrance effect on the depuration process. Decrease in the E HOMO values results in increasing the logk d values, implying important roles the molecular orbital energies may play in the biological depuration of PAHs in mussels. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.
Zhou, J.L., Zhang, Z., Banks, E., Grover, D.P. & Jiang, J.Q. 2009, 'Pharmaceutical residues in wastewater treatment works effluents and their impact on receiving river water', Journal of Hazardous Materials, vol. 166, no. 2-3, pp. 655-661.View/Download from: UTS OPUS or Publisher's site
Various pharmaceutical residues are being discharged from wastewater treatment works (WTW) effluents, the impact of which on river water quality is of high relevance to environmental risk assessment. The concentrations of eleven pharmaceutical compounds were determined in three WTWs in England, and the river Ouse receiving effluents from Scaynes Hill WTW. Results show that five compounds propranolol, sulfamethoxazole, carbamazepine, indomethacine and diclofenac were detected in all wastewater and river water samples, with carbamazepine showing the highest concentrations (up to 2336 ng L-1) in WTW influent. Different compounds were removed to different extent in the WTWs, varying from 43 to 92%, with the highest performance obtained by the WTW with tertiary treatment (sand filtration). The pharmaceutical residues from Scaynes Hill WTW were eventually discharged into the river Ouse, causing an elevation in their concentrations downstream of the outfall. This was confirmed by the good agreement between measured concentrations and those predicted by a simple dilution model.
Bignal, K.L., Langridge, S. & Zhou, J.L. 2008, 'Release of polycyclic aromatic hydrocarbons, carbon monoxide and particulate matter from biomass combustion in a wood-fired boiler under varying boiler conditions', Atmospheric Environment, vol. 42, no. 39, pp. 8863-8871.View/Download from: UTS OPUS or Publisher's site
Particulate matter, CO and NO as well as 16 polycyclic aromatic hydrocarbons (PAHs) in both gaseous and particulate phases were measured in the stack of a woodchip-fired 50 kW boiler used for domestic heating. The concentrations of SPAHs in both gas and particle phases varied from 1.3 to 1631.7 µg m-3. Mean CO and NO concentrations varied from 96 to 6002 ppm and from 28 to 359 ppm, respectively. The effects of fuel parameters (moisture content (MC) and tree species) and boiler operating conditions on pollutant concentrations were investigated. A relationship was established between SPAHs in gaseous and particulate phases and CO concentrations. The species of tree used for woodchip was less important than MC and boiler operating conditions in affecting pollutant concentrations. It is recommended that in order to minimise PAH release woodchip fuel should have a low MC, and the boiler should be operated with a load demand (high/moderate heat requirement). Slumber modes when the boiler has no load demand and is effectively a smouldering flame should be avoided. This can be achieved by increasing automatic operation capability of wood-fired boilers, for example, by automatically varying fire rates and having auto-start capabilities. The PAH data obtained from this study is particularly useful in contributing to emissions inventories, modelling, and predictions of ambient air quality
This paper discusses the occurrence and removal of endocrine disrupting chemicals (EDCs) in Horsham sewage treatment plant (STP), West Sussex, UK. Photodegradation aided by a catalyst (TiO2) was studied for its efficiency of removing EDCs from wastewater. The degradation of estrone and 17-estradiol under natural sunlight followed a pseudo-first-order kinetics, with a rate constant of 0.01 h-1. The degradation by sunlight is also independent of initial chemical concentration, suggesting some potential of using this environmentally friendly method for waste minimisation. In comparison, more efficient degradation was observed with UV irradiation (253 nm), with the rate constants being increased to 2.7 and 2.5 h-1 for the two compounds. Subsequent application of the photocatalysis method to real effluent treatment at Horsham STP was successful, as demonstrated by the non-detection of the target compounds following treatment.
Zhang, Z., Hibberd, A. & Zhou, J. 2008, 'Analysis of emerging contaminants in sewage effluent and river water: comparison between spot and passive sampling', Analytica Chimica Acta, vol. 607, no. 1, pp. 37-44.View/Download from: UTS OPUS or Publisher's site
Passive sampling is highly complimentary to spot sampling in environmental analysis. A polar organic chemical integrative sampler (POCIS) was extensively tested to optimize its performance under both controlled and field conditions. The passive sampler was subsequently used for the sampling and analysis of estrone, 17-estradiol, 17a-ethynylestradiol, bisphenol A, propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac and meclofenamic acid in sewage effluent and river water. Under laboratory conditions, the kinetics of compound uptake by POCIS were linear during 10-day of exposure. POCIS sampling rates of the target compounds were significantly greater by using polyethersulfone instead of polysulfone membrane, and enhanced with increasing sorbent exposure area. Together with spot water sampling, the optimized POCIS was deployed in the River Ouse, West Sussex, UK to obtain field-derived sampling rates which, for endocrine disrupting chemicals (EDCs), were significantly higher than those from laboratory experiments. Both spot and passive sampling demonstrated that most of the target chemicals were frequently detected in sewage effluent and river waters, and that the daily changes in the pollutant concentrations were greater for pharmaceuticals than for EDCs. The aqueous concentrations of all compounds were elevated at a sewage outfall, which is confirmed to be an important source of the target compounds in the river. The validated POCIS was then successfully used to estimate the concentrations of the target compounds in effluent and river water, which were in good agreement with those from spot sampling for pharmaceuticals.
Zhou, J.L. 2008, 'Occurrence and persistence of antifouling biocide Irgarol 1051 and its main metabolite in the coastal waters of Southern England', The Science of the Total Environment, vol. 406, no. 1-2, pp. 239-246.View/Download from: UTS OPUS or Publisher's site
The toxicity and persistence of antifouling booster biocides are of major concern. This study reports the occurrence of Irgarol 1051 and its degradation product M1, in coastal waters of Southern England, during 20042005. The highest concentrations of Irgarol 1051 were 89 ng/L in water and 45 ng/g dry weight in sediments, with an overall mean (n = 108) of 13 ng/L and 16 ng/g in water and sediments, respectively. As the degradation product of Irgarol 1051, M1 was less widespread, with the highest concentration of 30 ng/L in water and 14 ng/g in sediments, with an overall mean (n = 108) of 5 ng/L and 4 ng/g in water and sediments, respectively. Overall, the concentration of Irgarol 1051 and M1 decreased significantly during the sampling period and in comparison to earlier studies during 2000 to early 2004, indicating that control measures by restricting the use of Irgarol 1051 are effective in reducing its concentrations in coastal waters. The distribution of Irgarol 1051 between sediments and water was significantly related to sediment organic carbon content. In addition, significantly higher concentrations of Irgarol 1051 were detected in paint particles than in sediment. The rate of release of Irgarol 1051 from paint residues is very slow, with a half life of approximately 1 y. Two important findings are emerging, first the importance of organic rich sediments and paint residues as major sites of storage for Irgarol 1051, and secondly Irgarol 1051 may be classified as a persistent organic pollutant due to its long half life.
Gatidou, G., Thomaidis, N.S. & Zhou, J.L. 2007, 'Fate of Irgarol 1051, diuron and their main metabolites in two UK marine systems after restrictions in antifouling paints', Environment International, vol. 33, no. 1, pp. 70-77.View/Download from: UTS OPUS or Publisher's site
Two major antifouling biocides used worldwide, Irgarol 1051 and diuron, and their degradation products in Shoreham Harbour and Brighton Marina, UK were studied during 20032004. The highest concentrations of Irgarol 1051 were 136 and 102 ng L- 1 in water and 40 and 49 ng g- 1 dry weight in sediments for Shoreham Harbour and Brighton Marina, respectively. As the degradation product of Irgarol 1051, M1 was also widespread, with the highest concentration of 59 ng L- 1 in water and 23 ng g- 1 in sediments in Shoreham Harbour, and 37 ng L- 1 in water and 5.6 ng g- 1 in sediments in Brighton Marina. The target compounds showed enhanced concentrations during the boating season (MayJuly), when boats were being re-painted (JanuaryFebruary), and where the density of pleasure crafts was high. Overall, the concentration of Irgarol 1051 decreased significantly from late 2000 to early 2004, indicating the effectiveness of controlling its concentrations in the marine environment following restricted use. Diuron was only detected in 14% of water samples, and mostly absent from sediment samples.
King, A.J., Readman, J.W. & Zhou, J.L. 2007, 'Behaviour of polycyclic aromatic hydrocarbons in dissolved, colloidal, and particulate phases in sedimentary cores', International Journal of Environmental Analytical Chemistry, vol. 87, no. 3, pp. 211-225.View/Download from: UTS OPUS or Publisher's site
Solid-phase microextraction (SPME) has been successfully used for extracting polycyclic aromatic hydrocarbons (PAHs) from porewater samples from the Mersey Estuary, UK. The majority of the PAHs in porewater samples are associated with colloids due to the high DOC concentrations. The truly dissolved PAH concentrations varied from 66 to 1050 ng L -1 in core 2 and from 95 to 740 ng L-1 in core 3, and were dominated by naphthalene, fluoranthene, and pyrene. Although absent in the dissolved phase, the high-molecular-mass compounds were found in the colloid-associated fraction of porewater. PAHs in sediments arose from a range of compounds with 4- and 5-ring PAHs dominating. The partitioning of PAHs between sediment and porewater shows that PAHs are enriched in the sediment phase. When the soot carbon content was considered, predictions of the partition behaviour were found to agree more closely with the observed distribution. The results reiterate the importance of evaluating the speciation of organic pollutants in both porewater and sediments in order to accurately predict their environmental fate and potential toxicity. © 2007 Taylor & Francis.
Maskaoui, K., Hibberd, A. & Zhou, J.L. 2007, 'Assessment of the interactions between aquatic colloids and pharmaceuticals facilitated by cross-flow ultrafiltration', Environmental Science & Technology, vol. 41, no. 23, pp. 8038-8043.View/Download from: UTS OPUS or Publisher's site
Interactions between pharmaceuticals and aquatic colloids are a key process regulating their environmental fate, but poorly understood. A validated cross-flow ultrafiltration (CFUF) system was used to isolate river colloids and to determine the partition of selected pharmaceuticals between colloidal (>1 kDa but <0.7 µm) and dissolved phases (<1 kDa) by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The kinetics of pharmaceutical binding to colloids was rapid, reaching equilibrium within 5 min. The mass balance of chosen pharmaceuticals through CFUF system was satisfactory for propranolol, sulfamethoxazole, meberverine, carbamazepine, indomethacine, diclofenac, and meclofenamic acid. The partition coefficient normalized to colloidal organic carbon content (Kcoc) varied from 5.45 104 to 7.54 105 mL/g for the chosen pharmaceuticals, which are greater than those for endocrine disrupting chemicals (EDCs), suggesting substantially stronger colloidal interactions with pharmaceuticals than with EDCs. Linear relationships were demonstrated between log-Kcoc and pharmaceutical properties such as log Kow (octanolwater partition coefficient), highlighting the importance of compound hydrophobicity in controlling their binding with colloids. Such a finding is in contrast to that for EDCs whose Kcoc values were independent of their Kow values. The CFUF-LC-MS technique has the potential to become a widely applicable tool for quantifying the distribution of emerging organic pollutants between nanoparticles and the dissolved phase
Maskaoui, K., Hu, Z., Zhou, J. & Han, Y. 2007, 'Distribution and sources of polycyclic aromatic hydrocarbons in main aquacultural areas in Guangdong, China', Chinese Journal of Oceanology and Limnology, vol. 25, no. 2, pp. 166-173.View/Download from: Publisher's site
The environmental quality status of Daya Bay (22.56-22.77°N, 114.51-114.73°E), a main aquaculture area in Guangdong of China, was investigated using 16 polycyclic aromatic hydrocarbon (PAH) sediment samples of the bay. The total concentrations of 16 PAHs varied from 115 to 1 134 ng/g dry weight. The PAH composition pattern in sediments suggest dominance of 4-ring PAHs in Sites 2 and 4, and the ratio of certain related PAHs indicated important pyrolytic and petrogenic sources. The results enhance the understanding of current contamination levels and make a better assessment of likely impacts of organic contamination on ecosystems and the sustainability of local aquaculture in the area especially after the establishment of the Nuclear Power Station by the bay. © 2007 Science Press.
The TiO2-assisted photodegradation of two natural female hormones, estrone (E1) and 17-estradiol (E2), was investigated in two UV-photo-reactors, followed by solid-phase extraction and analysis by gas chromatographymass spectrometry (GCMS). The degradation of E1 and E2 in both reactors followed the pseudo-first-order kinetics. In reactor 1 (150 W), 97% of compounds were degraded within 4 h of irradiation. Even more rapid degradation was observed in reactor 2 (15 W) where 98% of both compounds disappeared within 1 h, due to the shorter wavelength of UV-light in reactor 2 (fixed at 253 nm) than reactor 1 (238579 nm). The influences of different initial chemical concentrations, pH value, the presence of dissolved organic matter and hydrogen dioxide, and the catalyst concentration on the degradation rate of E1 and E2 in aqueous solutions were investigated. The results show that the extent of photo-induced degradation of E1 and E2 strongly depends on the water constituents in solution. The degradation rate was increased when pH value was increased from 2 to 7.6, beyond which the degradation rate started to decrease. The presence of humic acid enhanced the degradation of E1 and E2 in both reactors as a result of photosensitisation effect of humic acid chromophore. The degradation rate increased with an increase in H2O2 concentration. The degradation rate was also enhanced by increasing catalyst concentration up to 2 g/l. The findings therefore suggest that photocatalysis can be a very effective method of rapidly removing certain EDCs from water.
Zhang, Z. & Zhou, J.L. 2007, 'Simultaneous determination of various pharmaceutical compounds in water by solid-phase extraction-liquid chromatography-tandem mass spectrometry', Journal of Chromatography A, vol. 1154, no. 1-2, pp. 205-213.View/Download from: UTS OPUS or Publisher's site
A solid-phase extraction (SPE) followed by liquid chromatographyelectrospray ionisation tandem mass spectrometry (LCESI-MSMS) method was developed and validated for simultaneous analysis of 11 pharmaceutical residues (propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, mecoprop, indomethacine, diclofenac, meclofenamic acid and monensin) in environmental water samples. The collision energy chosen for the multiple reaction monitoring (MRM) experiment was optimised. A number of parameters that may affect the recovery of the pharmaceuticals, such as the type of SPE cartridges, eluents, as well as water properties including pH value, salinity and concentration of colloid and surfactant were investigated. It is shown that the Oasis HLB SPE cartridge produced the best recoveries of the target pharmaceuticals while methanol was efficient in eluting pharmaceuticals from SPE cartridges. The recovery of some target compounds was enhanced with increasing salinity, but reduced by increasing pH value, and unaffected by surfactant concentration (010 µg/l). The recovery of most compounds was slightly increased by the presence of colloids (010 mg/l), which however caused a reduction in recovery for sulfamethoxazole and meberverine. The optimised method was further verified by performing spiking experiments in river water and seawater matrices, with good recovery and reproducibility for all except two compounds. The established method was successfully applied to environmental water samples from East Sussex, UK, for the determination of the target pharmaceuticals.
Zhou, J.L., Liu, R., Wilding, A. & Hibberd, A. 2007, 'Sorption of selected endocrine disrupting chemicals to different aquatic colloids', Environmental Science & Technology, vol. 41, no. 1, pp. 206-213.View/Download from: UTS OPUS or Publisher's site
The sorption of seven endocrine disrupting chemicals (EDCs) to aquatic colloids was determined by cross-flow ultrafiltration (CFUF) followed by gas chromatography-mass spectrometry (GC-MS). Results show that the colloidal organic carbon normalized sorption coefficient (Kcoc) of EDCs to different aquatic colloids varies by a factor of 6-12 because such colloids are of different origin. Through characterization of colloidal samples, a significant relationship was established between Kcoc values and the molar extinction coefficient of colloids at 280 nm, whereas no other colloidal properties such as elemental ratios were correlated with Kcoc values. The results are consistent with other reports of the importance of the quality of sorbents such as their aromatic carbon content in sorbing various organic pollutants. The presence of a surfactant was found to increase Kcoc values for estrone (E1) and 17a-ethynylestradiol (EE2). The method was subsequently applied for determining EDC concentrations in field samples, where both conventional and truly dissolved EDCs showed higher concentrations close to sewage outfalls than either upstream or downstream, confirming the source-concentration relationship. In addition, the truly dissolved EDC concentrations were lower than the conventional dissolved concentrations, confirming that there were interactions between aquatic colloids and EDCs. It is estimated that between 10 and 29% of EDCs are associated with aquatic colloids. As colloids are highly abundant in rivers and ocean, they will therefore play a significant role in the environmental behavior and fate of EDCs
Maskaoui, L., Hu, Z., Zhou, J.L. & Han, Y.L. 2006, 'Levels of polycyclic aromatic hydrocarbons in some agricultural, industrial and urban areas along Xiamen coastal waters, China', Journal of Environmental Sciences, vol. 18, pp. 318-322.View/Download from: UTS OPUS
An intensive investigation was conducted to study the distribution of polycyclic aromatic hydrocarbons (PAHs), to show firstly the level of pollution in the agricultural areas and analyses specifically the status of soil polluted by these persistent pollutants in some locations of Xiamen region. Soil samples collected from Jiulong agricultural catchment have been analysed for 16 PAH compounds, using gas chromatography flame ionization detection in order to determine the level of selected PAH components and to identify the factors that may control their distribution and persistence in the area. The main PAHs found in soil samples were the low molecular weight. The total PAHs detected in soil samples ranged from 0.50 to 0.95µg/g soil. The highest values of PAHs were significantly detected in the orange tree leaves, which range from 236.1 to 249.3µg/g soil showing recent atmospheric inputs of these volatile pollutants. The distribution of PAHs in vegetable were monitored and indicating that the concentration were high and ranged from 8.24 to 58.87µg/g. Other sediment samples were also collected and analysed from urban sewage (5.26µg/g dw), aquacultura (0.52µg/g dw) and industrial areas (from 0.62 to 2.09µg/g dw), during this investigation. The contamination of Jiulong river estuary and Xiamen Western Sea by PAHs has been then widely justified by wastewater discharges and soil runoffs from these areas. The results, therefore, provide important information on the current contamination status caused by the atmospheric transport and point to the need for urgent actions to stop the release of these hydrocarbons to the environment. The necessity of implementing systematic monitoring of PAHs is also emphasized.
Zhang, Z., Hibberd, A. & Zhou, J.L. 2006, 'Optimisation of derivatisation for the analysis of estrogenic compounds in water by solid-phase extraction-gas chromatography-mass spectrometry', Analytica Chimica Acta, vol. 577, no. 1, pp. 52-61.View/Download from: UTS OPUS or Publisher's site
An optimisation of derivatisation methods for the simultaneous determination of endocrine disrupting chemicals (EDCs) in water by solid-phase extraction (SPE) gas chromatographymass spectrometry (GCMS) was developed in this study. Seven highly potent EDCs including 17-estradiol (E2), estrone (E1), 16a-hydroxyestrone, 17a-ethynylestradiol (EE2), bisphenol A, 4-nonylphenol and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used for the extraction recoveries of compounds from water and effluent samples. The stability of the silylation derivatives under different reaction conditions was investigated. The combined use of BSTFA and pyridine as derivatisation reagents, together with the use of hexane as the final solvent, was preferred in order to generate more stable derivatives of EDCs. The relative response factor (RRF) of all derivatives except that of EE2 was stable 120 h after derivatisation. The addition of pyridine as derivatisation reagent with BSTFA can prevent the conversion of EE2 to other products during the reaction. Several parameters that may affect the recovery of EDCs, such as the SPE flow rate, and water properties including aquatic colloid content and surfactant concentration were tested. The results showed that the flow rate (125 mL min-1), colloid concentration (050 mg L-1) and surfactants concentration (010 µg L-1) did not cause significant decrease in the EDCs recovery.
Zhou, J.L. 2006, 'Sorption and remobilization behavior of 4-tert-octylphenol in aquatic systems', Environmental Science & Technology, vol. 40, no. 7, pp. 2225-2234.View/Download from: UTS OPUS or Publisher's site
The sorption and desorption of 4-tert-octylphenol in aquatic systems were studied to unravel the underlying controls. The sorption process was relatively slow, reaching a final sorption equilibrium in 10 d. The sorption process was interpreted as consisting of two stages:? an initial rapid adsorption on particle surface followed by a slow intraparticle diffusion. The key parameter affecting the sorption of 4-tert-octylphenol by sediment is the occurrence of colloids, which in turn explains the so-called sediment concentration (SC) effect. This was confirmed by the increasing amount of colloids with increasing SC, and the relative constancy of intrinsic partition coefficient of 4-tert-octylphenol between sediment and water (Kp) and between colloids and water (Kc). Further evidence was from the nonoccurrence of SC effect from the addition of the same amount of colloids in different SC. The adsorption equilibrium is best described by the Freundlich model at low equilibrium concentrations. The adsorption of 4-tert-octylphenol was enhanced in the presence of salts, due to the salting out effect, and a salting constant of 1.3 L/mol was obtained. Desorption experiments showed that the release of 4-tert-octylphenol from contaminated sediments was highly dependent on the age of sediments, with kinetics of desorption being much faster in fresh sediments than in aged sediments.
Jiang, J.Q., Yin, Q., Zhou, J. & Pearce, P. 2005, 'A survey of endocrine disrupting chemicals in sewage and a preliminary treatment trial', Water Science & Technology: Water Supply, vol. 52, no. 8, pp. 1-7.View/Download from: UTS OPUS
This paper demonstrates that synthetic endocrine disrupting chemicals (EDCs) (e.g. bisphenol-A) and natural EDCs (e.g. estrone and 17-estradiol) were found in the crude sewage from two sewage treatment works. Conventional biological processes can lower EDC concentrations to several hundred nanograms per litre. Because natural EDCs (e.g. estrone and 171-estradiol) have biological activity and an adverse impact on the environment at extremely low concentrations (several tens of nanograms per litre), and because the existing wastewater/sewage treatment processes are not adequate to reduce natural EDC concentrations lower than 100?ng?L-1, further treatment after conventional biological processes is required. Preliminary trials with ferrate(VI) and electrochemical oxidation processes demonstrated that the former is more effective than the latter in reducing EDC concentrations, and that both the processes can effectively reduce EDCs to very low levels, ranging between 20 and 100?ng?L-1.
Jiang, J.Q., Yin, Q., Zhou, J.L. & Pearce, P. 2005, 'Occurrence and treatment trials of endocrine disrupting chemicals (EDCs) in wastewaters', Chemosphere, vol. 61, no. 4, pp. 544-550.View/Download from: UTS OPUS or Publisher's site
This study demonstrates that both synthetic and natural endocrine disrupting chemicals (EDCs) (e.g., bisphenol A, estrone and 17-estradiol) were found in the crude wastewaters from two wastewater treatment works (WwTWs). Conventional biological processes can lower EDCs concentrations to several tens to hundreds ng l-1. Since natural EDCs (e.g., estrone and 17-estradiol) have biological activity and adverse impact on the environment at extremely low concentrations (several tens of ng l-1), further treatment after conventional biological processes is required. Preliminary trials with ferrate(VI) and electrochemical oxidation process demonstrated that both processes can effectively reduce EDCs to very low levels, ranging between 10 and 100 ng l-1, but the former is more effective than the latter to reduce COD concentration in wastewater for given studying conditions.
Liu, R., Wilding, A., Hibberd, A. & Zhou, J.L. 2005, 'Partition of endocrine-disrupting chemicals between colloids and dissolved phase as determined by cross-flow ultrafiltration', Environmental Science & Technology, vol. 39, no. 8, pp. 2753-2761.View/Download from: UTS OPUS
Cross-flow ultrafiltration (CFUF) was developed first for the isolation of natural colloids and subsequently for determining the partition of selected endocrine-disrupting chemicals (EDCs) between river colloids and dissolved phase. In this study, a 1-kDa Millipore Pellicon 2 cartridge type CFUF system was validated using a range of molecular probes spiked in natural waters. Results show that good retention (>80%) of high molecular weight (HMW, >1 kDa) molecules and low retention of low molecular weight (LMW, <1 kDa) molecules can be achieved at high concentration factor (cf) values in sampling mode or over long time scales in recirculation mode. The interactions between aquatic colloids and EDCs were studied by mixing EDCs, water, and colloids previously isolated by CFUF for a certain duration, followed by the separation of the target compounds between the truly dissolved and colloid-bound phases by CFUF and analysis by gas chromatography-mass spectrometry (GC-MS). The kinetics of EDCs binding to colloids were relatively rapid, reaching equilibrium within 5 min. The mass balance of chosen EDCs through CFUF system was fully investigated, with good recovery for the relatively polar EDCs such as estrone and 17-estradiol. On the basis of EDC sorption by colloids, the partition coefficient normalized to colloidal organic carbon content (Kcoc) was 8.85 103, 1.50 104, 8.85 103, 4.87 104, and 1.59 104 mL/g for bisphenol A, estrone, 17-estradiol, 17a-ethynylestradiol, and 16a-hydroxyestrone, respectively, which are comparable with the values reported in the literature. In addition, it has been shown that the Kcoc values of EDCs were relatively independent of their octanol-water partition coefficient (Kow) values, suggesting the important role of different binding mechanisms other than nonspecific hydrophobic interaction between EDCs and natural colloids. As the CFUF-GC-MS method can be used to quantify very low concentration of pollutants and is not limited t...
Maskaoui, K., Zhou, J.L., Han, Y.L., Hu, Z., Zheng, T.L. & Hong, H.S. 2005, 'Contamination of soil, leaves and vegetables by polychlorinated biphenyls in Xiamen region, China', Journal of Environmental Sciences, vol. 17, no. 3, pp. 460-464.View/Download from: UTS OPUS
The paper aimed to identify the primary of polychlorinated biphenyls (PCBs) in the diulong River Estuary, investigate the spatial distribution of PCBs contamination in the environment, localize the atmospheric source and evaluate ongoing PCBs emissions by analyzing soil samples collected along the Jiulong River region. In addition, the accumulation of PCBs in the human food chain was quantified by analyzing leaf of orange trees and vegetable samples collected along a gradient of soil/atmospheric contamination moving away from the source. Consequently, the impact on the human health and the ecosystem was quantified, different management options were proposedto reduce this impact and to carry out research on organic contaminants along the Jiulong River and Xiamen region.
Maskaoui, K., Zhou, J.L., Zheng, T.L., Hong, H.S. & Yu, Z. 2005, 'Organochlorine micropollutants in the Jiulong River Estuary and Western Xiamen Sea, China', Marine Pollution Bulletin, vol. 51, no. 8, pp. 950-959.View/Download from: UTS OPUS or Publisher's site
Organochlorine contaminants including 12 polychlorinated biphenyl (PCB) congeners and 18 insecticides were determined in water, pore water and sediments of the Jiulong River Estuary and Western Xiamen Sea, China. The results showed that the levels of the total PCBs ranged from non-detectable to 1500 ng l-1 in water, from 209 to 3870 ng l-1 in pore water, and from 2.78 to 14.8 ng g-1 dry weight in sediments. Total organochlorine insecticide concentrations were from below the limit of detection to 2480 ng l-1 in water, from 267 to 33400 ng l-1 in pore water, and from 4.22 to 46.3 ng g-1 dry weight in sediments. Concentrations of PCBs and insecticides in pore water were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. The PCB congeners with the highest concentrations were CB153, CB180 and CB194, which together accounted for 6887% of total PCBs in water, pore water and sediment. Among the hexachlorocyclohexane (HCH) compounds, beta-HCH was found to be a major isomer. Analysis of 1,1,1-trichloro-2,2-bis-chlorophenyl-ethane (DDT) and its metabolites showed that 1,1-dichloro-2[o-chlorophenyl]-2[p-chlorophenyl]-ethylene (DDE) was dominant in the group. In comparison to a 1998 study in the Western Xiamen Sea, levels of organochlorines were enhanced due probably to recent inputs and changes in sediments.
Wilding, A., Liu, R. & Zhou, J.L. 2005, 'Dynamic behaviour of river colloidal and dissolved organic matter through cross-flow ultrafiltration system', Journal of Colloid and Intrface Science, vol. 251, no. 2, pp. 152-158.View/Download from: UTS OPUS
Through cross-flow filtration (CFF) with a 1-kDa regenerated cellulose Pellicon 2 module, the ultrafiltration characteristics of river organic matter from Longford Stream, UK, were investigated. The concentration of organic carbon (OC) in the retentate in the Longford Stream samples increased substantially with the concentration factor (cf ), reaching approximately 40 mg/L at cf 15. The results of dissolved organic carbon (DOC) and colloidal organic carbon (COC) analysis, tracking the isolation of colloids from river waters, show that 2 mg/L of COC was present in those samples and good OC mass balance (77101%) was achieved. Fluorescence measurements were carried out for the investigation of retentate and permeate behaviour of coloured dissolved organic materials (CDOM). The concentrations of CDOM in both the retentate and permeate increased with increasing cf , although CDOM were significantly more concentrated in the retentate. The permeation model expressing the correlation between loglog[CDOM] in the permeate and logcflogcf was able to describe the permeation behaviour of CDOM in the river water with regression coefficients (r2r2) of 0.94 and 0.98. Dry weight analysis indicated that the levels of organic colloidal particles were from 49 to 71%, and between 29 and 51% of colloidal particles present were inorganic. COC as a percentage of DOC was found to be 1016% for Longford Stream samples.
Endocrine disrupting chemicals (EDCs) are the focus of current environment concern, as they can cause adverse health effects in an intact organism, or its progeny, subsequent to endocrine function. The paper reports on the removal of estrone (E1) and 17-estradiol (E2) from water through the use of various adsorbents including granular activated carbon (GAC), chitin, chitosan, ion exchange resin and a carbonaceous adsorbent prepared from industrial waste. The results show that the kinetics of adsorption were adsorbent and compound-dependent, with equilibration being reached within 2 h for a waste-derived carbonaceous adsorbent to 71 h for an ion-exchange resin for E1, and within 7 h for the waste-derived carbonaceous adsorbent to 125 h for GAC for E2. Of all the adsorbents tested, the carbonaceous adsorbent showed the highest adsorption capacity, with a maximum adsorption constant of 87500 ml/g for E1 and 116000 ml/g for E2. The GAC also had a very high adsorption capacity for the two compounds, with a maximum adsorption constant of 9290 ml/g for E1 and 12200 ml/g for E2. The effects of some fundamental environmental parameters including adsorbent concentration, pH, salinity and the presence of humic acid and surfactant on adsorption were studied. The results show that adsorption capacity of activated carbon was decreased with an increase in adsorbent concentration and by the presence of surfactant and humic acid. The results have demonstrated excellent performance of a waste derived adsorbent in removing E1 and E2 from water, and indicated the potential of converting certain solid waste into useful adsorbents for pollution-control purposes.
Zhang, Z., Yu, G., Cheng, J., Wang, X., Zhang, F. & Zhou, J. 2005, 'Carbon isotopic fractionation during photolysis of hexachlorobenzene', Progress in Natural Science, vol. 15, no. SUPPL., pp. 82-88.View/Download from: Publisher's site
The occurrence of carbon isotope fractionation during dechlorination of hexachlorobenzene (HCB) to pentachlorobenzene (penta-CB) has been evaluated under ultraviolet irradiation in a photo-reactor. Stable carbon isotope ratios ( 13 C) of HCB and penta-CB increase from -27.3‰ to 18.8‰ and from -33.9‰ to -19.5‰, respectively. The isotopic fractionations of the reactants and products are described with the Rayleigh model, and the following enrichment factors () are obtained: -14.8‰ for the dechlorination of HCB and 22.7‰ for the dechlorination product (penta-CB). With the initial 13 C value of HCB, this enrichment factor can be used to estimate the fraction (f) of HCB remaining by Rayleigh equation. Strong enrichment of 13 C in HCB and penta-CB during photochemical dechlorination might serve as a powerful tool to monitor the photolysis process, such information may provide additional evidence to aid in further understanding of the biogeochemical processes these compounds will undergo in the environment.
Gatidou, G., Zhou, J.L. & Thomaidis, N.S. 2004, 'Microwave-assisted extraction of Irgarol 1051 and its main degradation product from marine sediments using water as the extractant followed by gas chromatographymass spectrometry determination', Journal of Chromatography A, pp. 41-48.View/Download from: UTS OPUS
A microwave-assisted extraction (MAE) method for the determination of Irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) and its main degradation product M1 (2-methylthio-4-tert-butylamino-s-triazine) in marine sediments by gas chromatographymass spectrometry (GCMS) was developed. The key parameters of MAE procedure, including the amount of the sediment, the volume of the extraction solvent, the duration and the temperature of the extraction procedure were optimized. The extraction procedure was followed by solid-phase extraction (SPE) on reverse phase C18 cartridges. The isolation of the target compounds from the matrix was found to be efficient when 3 g of marine sediment were extracted with 30 ml of water for 10 min at 115 °C. Final determination was accomplished by GCMS. Quantification was performed with matrix-matched calibration using atrazine-d5 as internal standard. Mean recoveries higher than 85.4% were obtained for both compounds at three fortification levels with relative standard deviations (R.S.D.) = 14%. The limits of detection (LOD) of the developed method were 0.9 and 1.7 ng g-1 dry weight for M1 and Irgarol 1051, respectively.
King, A.J., Readman, J.W. & Zhou, J.L. 2004, 'Determination of polycyclic aromatic hydrocarbons in water by solid-phase microextractiongas chromatographymass spectrometry', Analytica Chimica Acta, vol. 523, no. 2, pp. 259-267.View/Download from: UTS OPUS or Publisher's site
A solid-phase microextraction (SPME)gas chromatography (GC)mass spectrometry (MS) analytical method for the simultaneous separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) from aqueous samples has been developed, based on the sorption of target analytes on a selectively sorptive fibre and subsequent desorption of analytes directly into GCMS. The influence of various parameters on PAH extraction efficiency by SPME was thoroughly studied. Results show that the fibre exposure time and the use of agitation during exposure are critical in enhancing SPME performance. The presence of colloidal organic matter (as simulated by humic acid) in water samples is shown to significantly reduce the extraction efficiency, suggesting that SPME primarily extracts the truly dissolved compounds. This offers the significant advantage of allowing the differentiation between freely available dissolved compounds and those associated with humic material and potentially biologically unavailable. The method showed good linearity up to 10 µg/l. The reproducibility of the measurements expressed as relative standard deviation (R.S.D.) was generally <20%. The method developed was then applied to extract PAHs from sediment porewater samples collected from the Mersey Estuary, UK. Total PAH concentrations in porewater were found to vary between 95 and 742 ng/l with two to four ring PAHs predominating. Results suggest that SPME has the potential to accurately determine the dissolved concentrations of PAHs in sediment porewater.
King, A.J., Readman, J.W. & Zhou, J.L. 2004, 'Dynamic behaviour of polycyclic aromatic hydrocarbons in Brighton marina, UK', Marine Pollution Bulletin, vol. 48, no. 3-4, pp. 229-239.View/Download from: UTS OPUS or Publisher's site
The distribution of polycyclic aromatic hydrocarbons (PAHs) between various phases is fundamental in the control of their movement and impact in the marine environment. In this study samples of water and sediments were regularly collected from Brighton marina, UK, to quantify the intensity, spatial and temporal variations of PAH contamination. The results show clearly that PAH behaviour in marine systems is highly complex, and controlled by the interplay of PAH sources, compound physicochemical properties, water and sediment movement, and field conditions. Levels of total PAHs (16 compounds) in the dissolved phase were found to vary between <2 and 11,400 ng/l, with higher values observed in the winter months. Total PAH concentration in sediment samples varied between 24 and 4710 ng/g dry weight. PAHs in water were dominated by low molecular mass compounds (2-ring), while PAHs in sediments were mainly derived from 24 ring compounds. In addition, dissolved concentrations were increased during sediment dredging and after a period of severe rainfall. PAHs in Brighton marina are likely to be from both pyrolytic and petrogenic sources; as a result, field-derived distribution coefficients for individual PAHs between sediment and water tend to follow the equilibrium partition models, although slight exceedance is apparent. The extended partition model incorporating soot carbon has achieved limited success in better predicting PAH behaviour.
Liu, R., Zhou, J.L. & Wilding, A. 2004, 'Microwave-assisted extraction followed by gas chromatographymass spectrometry for the determination of endocrine disrupting chemicals in river sediments', Journal of Chromatography A, vol. 1038, no. 1-2, pp. 19-26.View/Download from: UTS OPUS or Publisher's site
In this study, microwave-assisted extraction (MAE) followed by gas chromatography (GC)mass spectrometry (MS) analysis has been successfully developed for the simultaneous extraction and determination of contrasting endocrine disrupting chemicals (EDCs) including 17-estradiol, estrone, 17a-ethynylestradiol, 16a-hydroxyestrone, 4-nonylphenol, 4-tert-octylphenol and bisphenol A in river sediments. For MAE, the effects of various parameters on the extraction efficiency were investigated. It is shown that the most efficient extraction (recovery >74%) of the target compounds was achieved by using methanol as the solvent, an extraction temperature of 110 °C and 15 min of holding time. The cleanup of extracts was carried out by passage through a non-deactivated silica gel column, and a satisfactory elution efficiency of all compounds was achieved using a solvent mixture of ethyl acetatehexane (4:6, v/v). The spiking experiments show that the mean recovery of the target compounds exceeded 61% at a spiking level of 5 ng/g dry mass, and 73% at 10, 40 and 100 ng/g dry mass with a good reproducibility. The method developed was applied to the determination of target EDCs in river sediments collected from rivers Uck and Ouse, UK, and results revealed the presence of the chosen compounds at low ng/g level.
Liu, R., Zhou, J.L. & Wilding, A. 2004, 'Simultaneous determination of endocrine disrupting phenolic compounds and steroids in water by solid-phase extractiongas chromatographymass spectrometry', Journal of Chromatography A, vol. 1022, no. 1-2, pp. 179-189.View/Download from: UTS OPUS or Publisher's site
A solid-phase extraction (SPE)gas chromatography (GC)mass spectrometry (MS) analytical method for the simultaneous separation and determination of endocrine disrupting chemicals (EDCs) from water samples is described in detail. Important and contrasting EDCs including estrone, 17-estradiol, 17a-ethynylestradiol, 16a-hydroxyestrone, 4-nonylphenol, bisphenol A and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with bis (trimethylsilyl) trifluoroacetamide was used for the extraction recoveries of target compounds from water samples. A number of parameters that may affect the recovery of EDCs, such as the type of SPE cartridges, eluents, as well as water properties including pH value, and concentration of salts and humic substances were investigated. It is shown that the Oasis cartridges produced the best recoveries of target EDCs while ethyl acetate was efficient in eluting EDCs from SPE cartridges. The recovery of some EDCs was enhanced by the addition of salt, but reduced by the increase in pH value and humic acid concentration. The optimised method was further verified by performing spiking experiments in natural river water and seawater matrices, with good recovery and reproducibility for all the selected compounds. The established method was successfully applied to environmental water samples from East and West Sussex, UK, for the determination of the target EDCs.
Wilding, A., Liu, R. & Zhou, J.L. 2004, 'Validation of cross-flow ultrafiltration for sampling of colloidal particles from aquatic systems', Journal of Colloid and Intrface Science, vol. 280, no. 1, pp. 102-112.View/Download from: UTS OPUS or Publisher's site
The use of cross-flow ultrafiltration (CFF) for the isolation of colloids from the bulk aquatic matrices has been increasing over the last decade; however, a thorough validation of each CFF system is needed before its application to natural samples. Laboratory experiments have been conducted to validate a 1-kDa Millipore Pellicon 2 cartridge type CFF system, using a range of molecular probes spiked in natural waters. Using the separation data of these probes, key validation parameters have been calculated, including retention coefficient (RC), concentration factor (cf), colloid concentration, recovery, and mass balance. The permeation behaviour of these molecules has also been studied using a simple permeation model. Results show that good retention (>80%) of high molecular weight (HMW, >1 kDa) molecules and low retention (<20%) of low molecular weight (LMW, <1 kDa) molecules can be achieved at high cf values or over long timescales. In addition, permeation modelling and the calculation of colloid concentration demonstrate the same findings, again recommending high cf values or long timescales for ultrafiltration to minimise the retention of LMW molecules. The retention characteristics of 3-kDa dextran change slightly with salinity. Mass balance calculations show good recoveries for all of the molecules tested. The apparent membrane molecular cut-off of the CFF system has been estimated to be between 2.1 and 2.5 kDa, which is slightly greater than the manufacturer's nominal MW cut-off of 1 kDa.
Zhang, Z.L., Hong, H.S., Zhou, J.L. & Yu, G. 2004, 'Phase association of polycyclic aromatic hydrocarbons in the Minjiang River Estuary, China', The Science of the Total Environment, vol. 323, no. 1-3, pp. 71-86.View/Download from: UTS OPUS or Publisher's site
Persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work the levels of 16 priority PAHs were determined in water, pore water, sediment, soil and vegetable samples from Minjiang River Estuary, China. Total PAH concentrations varied from 9.9 to 474 µg/l in water, 82.1 to 239 µg/l in pore water, 112 to 877 ng/g dry wt. in surficial sediments, 128 to 465 ng/g dry wt. in soil and 8600 to 111 000 ng/g dry wt. in Chinese vegetables. Overall, the mean concentrations of PAHs were present in higher levels in pore water than that in surface water, due possibly to higher concentrations of dissolved organic carbon or colloids with which the hydrophobic pollutants were strongly associated. Such a concentration gradient implies a potential flux of pollutants from sediment pore water to overlying water. Contamination was dominated by high molecular mass PAH compounds in all samples, indicating combustion-derived sources (for example, pyrolysis at high temperature). The levels of PAHs in water and vegetable were relatively high in comparison to other studies, although PAHs in sediment and soil were comparable to those found in many other similar environments. The ratios of selected PAHs indicated again that PAHs in Minjiang River Estuary were mainly derived from incomplete combustion of fossil fuel.
Bowman, J.C., Readman, J.W. & Zhou, J.L. 2003, 'Seasonal variability in the concentrations of Irgarol 1051 in Brighton Marina, UK; including the impact of dredging', Marine Pollution Bulletin, vol. 46, no. 4, pp. 444-451.View/Download from: UTS OPUS or Publisher's site
Variations in Irgarol 1051 concentrations in the UKs largest marina at Brighton were determined regularly over a period of one year. Aqueous concentrations ranged from <1 to 960 ng l-1 with highest mean concentrations generally associated with berths for larger vessels and with the main channels. Temporally, highest concentrations were recorded in November through to January and were probably associated with maintenance of vessels in an adjacent boatyard. Elevated levels were also encountered at the beginning of the season, coinciding with the introduction of newly antifouled vessels. Increased concentrations also followed dredging, possibly through re-mobilisation of Irgarol 1051. No correlations were found between dissolved Irgarol 1051 concentrations and pH, temperature or salinity. With the exception of sporadically high concentrations recorded for water samples (probably taken in close proximity to recently antifouled vessels), concentrations rarely exceeded the no observed effect concentration for marine periphyton of 63 ng l-1. Concentrations of Irgarol 1051 in sediments sampled from the marina ranged from <1 to 77 ng g-1. Apparent distribution coefficients (Kd) calculated from sedimentary and aqueous samples (collected simultaneously) are generally within the range of Kds reported from laboratory experiments.
Bowman, J.C., Readman, J.W. & Zhou, J.L. 2003, 'Sorption of the natural endocrine disruptors, oestrone and 17 beta-oestradiol in the aquatic environment.', Environmental geochemistry and health, vol. 25, no. 1, pp. 63-67.View/Download from: Publisher's site
Adsorption of hydrophobic contaminants at the particle/water interface is one of the key processes controlling their fate in the aquatic environment. The sorption of the natural female hormones oestrone and 17 beta-oestradiol has been studied under simulated riverine conditions. Both the kinetics and the effects of varying fundamental environmental parameters (e.g. sediment properties) on the thermodynamic equilibrium partition coefficient (Kp) have been studied in continuous and batch sorption experiments, respectively. Results showed that the sorption of oestrone and 17 beta-oestradiol by sediment was relatively slow, reaching equilibrium in 50 days. In addition, relatively small adsorption of both oestrone and 17 beta-oestradiol onto the sediment was observed, with Kp values between 200 and 250 mL g-1. The comparable Kp values of the two compounds reflect their structural similarity. It can be concluded that the two endocrine disruptors, oestrone and 17 beta-oestradiol remain primarily in association with the aqueous phase.
King, A.J., Readman, J.W. & Zhou, J.L. 2003, 'The application of solid-phase micro-extraction (SPME) to the analysis of polycyclic aromatic hydrocarbons (PAHs).', Environmental geochemistry and health, vol. 25, no. 1, pp. 69-75.View/Download from: Publisher's site
There are many established extraction techniques regularly used in the isolation and analysis of PAHs and similar organic compounds from various phases. These include Soxhlet or ultrasonic extractions from solids, and liquid-liquid or solid-phase extraction from aqueous samples. However, these methods have some inherent disadvantages; most require large volumes of organic solvents, they can be time consuming and many involve multi-step processes that always present the risk of the loss of some analytes (Zhang et al., 1994). Solid-phase micro-extraction (SPME) is a relatively new technique that has been used with much success in the analysis of a variety of compounds including PAHs. Experiments are being carried out to determine the optimum range of conditions for the extraction of a range of PAHs. Parameters under investigation include temperature, equilibration time, salinity and compound concentration. Presented here are some preliminary experiments into the applicability of SPME for PAH analysis. Further work will investigate the reproducibility of the technique, limits of detection and matrix effects. When an optimised method has been developed the technique will be used in investigations into PAH profiles in sediment cores.
Zhang, Z.L., Hong, H.S., Zhou, J.L., Huang, J. & Yu, G. 2003, 'Fate and assessment of persistent organic pollutants in water and sediment from Minjiang River Estuary, Southeast China', Chemosphere, vol. 52, no. 9, pp. 1423-1430.View/Download from: UTS OPUS or Publisher's site
Persistent organochlorine compounds were analyzed in surface water, porewater and surficial sediment samples from Minjiang River Estuary, which is the first large river in Fujian Province, Southeast of China. The total concentrations of 18 organochlorine pesticides were 214.41819, 454113 699 ng/l, 28.7952.07 ng/g in surface water, porewater and sediments (dry weight) respectively, and those of 21 polychlorinated biphenyls (PCBs) in the three phases were: 203.92473, 319210 855 ng/l, 15.1457.93 ng/g respectively. The results showed that the concentrations of these selected organochlorine pesticides and PCBs in porewater were higher than those in surface water. It may be due to the fact that these organic hydrophobic pollutants tend to stay in the sediments, and then re-suspend from the sedimentary phase to the upper water. We have analyzed the distribution characteristics of individual organochlorine pesticide components and PCBs, and found that a-HCH, DDE, Heptachlor, Endosulfan II, Methoxychlor were the most common organochlorine pesticides contaminants. Considering the groups of HCHs (HCHs = a-HCH + -HCH + ?-HCH + d-HCH) and DDTs (DDTs = DDT + DDD + DDE), the predominance of -HCH, DDE in all water, porewater and sediment samples was clearly observed. This observation suggested that -HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD, of which DDE that was more un-degradable. The PCB congeners containing 36 chlorines had the great preponderance in the three phase. These results were compared with those present in other estuaries and harbors. A risk assessment was evaluated for the persistent organic pollutants in the Minjiang River Estuary.
Zhou, J.L. & Maskaoui, K. 2003, 'Distribution of polycyclic aromatic hydrocarbons in water and surface sediments from Daya Bay, China', Environmental Pollution, vol. 121, no. 2, pp. 269-281.View/Download from: UTS OPUS or Publisher's site
Marine culture is thriving in China and represents a major component of the regional economy in coastal zones, yet the environmental quality of many of those areas has never been studied. This paper attempts to investigate the quality status of Daya Bay, a key aquaculture area in China. The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in water and sediment samples of the bay. The total concentrations of 16 PAHs varied from 4228 to 29?325 ng l-1 in water, and from 115 to 1134 ng g-1 dry weight in sediments. In comparison to many other marine systems studied, the PAH levels in Daya Bay waters were relatively high, and at six sites they were sufficiently high (>10 µg l-1) to cause acute toxicity. The PAH composition pattern in sediments suggest dominance by medium to high molecular weight compounds, and the ratio of certain related PAHs indicate important pyrolytic and petrogenic sources. Further analysis showed that the distribution coefficient (KD) increased with the particular organic carbon content of sediments, consistent with the PAH partition theory. The organic carbon normalised distribution coefficient (Koc) also increased with the compounds' octanol/water partition coefficient (Kow), confirming the potential applicability of the linear free energy relationships in the modelling and prediction of PAH behaviour in marine environments.
The distribution of trace metals Zn, Ni, Mn, Fe, Cu, Pb, Cd and Cr between suspended particulate matter (SPM) and water in the Conwy estuary, North Wales, has been studied in three surveys in 1998. Dissolved Cu and Mn showed some monthly variations. Most of the dissolved trace metals displayed a negative association with salinity, indicating rivers as a major source of inputs for them. Particulate Zn, Mn and Fe showed a decreasing concentration seaward, whilst the levels of Ni, Cu, Cr and Pb increased with salinity. SPM concentration was the most important variable significantly related to trace metal concentrations in SPM, with an inverse relationship between the two parameters. This was explained by the relative enrichment of trace metals in fine particles at low SPM concentrations and relative depletion of trace metals in coarse particles at high SPM concentrations. Particulate Zn, Mn and Pb were dominated by the fraction available to acetic acid (non-detrital), whilst particulate Ni, Fe and Cr were dominated by the fraction available to nitric acid (detrital). The partition coefficient of trace metals between SPM and water declined with increasing SPM concentration, consistent with the so-called particle concentration effect. Such a phenomenon may be explained by the presence of fine particles (including colloids) enriched with trace metals at low SPM concentrations, and the salinity-induced desorption.
Bowman, J.C., Zhou, J.L. & Readman, J.W. 2002, 'Sediment-water interactions of natural oestrogens under estuarine conditions', Marine Chemistry, vol. 77, no. 4, pp. 263-276.View/Download from: UTS OPUS or Publisher's site
The natural human female hormones oestrone and 17-oestradiol have been implicated in the disruption of endocrine systems in some wildlife adjacent to sewage effluents. The sorption behaviour of these two compounds under estuarine conditions was studied by spiking either 2.55 µg of oestrone or 2.65 µg of 17-oestradiol in kinetic experiments. In equilibrium experiments, 3 ng of oestrone or 3.2 ng of 17-oestradiol was added in each of the centrifuge tubes. Sorption onto sediment particles was relatively slow, with sorption equilibrium being reached in about 70 and 170 h for oestrone and 17-oestradiol, respectively. The effects of a variety of environmental parameters on sorption were studied including salinity, sediment concentration (SC), the presence of a third phase, particle size and, also, surfactant concentrations. Results show that although salinity did not induce any statistically significant effect on the sorption of 17-oestradiol, it did statistically enhance the sorption of oestrone, and a salting constant of 0.3 l mol-1 was derived. The partition coefficient for both compounds decreased with increasing sediment concentration, a phenomenon that has been widely reported and attributed to the presence of colloids (which could enhance dissolved concentrations). In this paper, the true partition coefficients for sediment particles (Kptrue) and colloidal particles (Kctrue) have been calculated, and a Kptrue value of 141 and 102 ml g-1 was obtained for oestrone and 17-oestradiol, respectively. In addition, Kctrue values for oestrone (222102 ml g-1) and 17-oestradiol (135102 ml g-1) were two orders of magnitude higher than their respective Kptrue values, suggesting that the colloidal particles are significantly stronger sorbents for natural oestrogens than sediment particles. Particles of different sizes were found to have different partition coefficients due to the strong relationships between partition coefficients for the two compounds and particulat...
Bowman, J.C., Zhou, J.L. & Readman, J.W. 2002, 'Sorption and desorption of benzo(a)pyrene in aquatic systems', Journal of Environmental Monitoring, vol. 4, no. 5, pp. 761-766.View/Download from: UTS OPUS or Publisher's site
The sorptive behaviour of polycyclic aromatic hydrocarbons (PAHs) is critical to controlling their transport, fates and effects in the environment. Experiments are described which detail the behaviour of a model compound (benzo(a)pyrene) under simulated aquatic conditions. The kinetics of sorption were comparable to those of other PAH compounds. The sorption equilibrium was extensively studied and found to be affected by several key parameters, notably sediment concentration. The sorption coefficient decreased substantially with the sediment concentration, from 9580 ml g-1 at a sediment concentration of 0.067 g l-1 to 1110 ml g-1 at a sediment concentration of 9.8 g l-1. The results are consistent with previous reports and often explained by the presence of colloids. In this paper the dry weight concentration of colloids was determined and used for deriving the true sorption coefficient, which is up to an order of magnitude higher than the observed partition coefficient. The sorption of benzo(a)pyrene was also dependent on some of the particle properties, and the sorption coefficient was found to increase with the organic carbon content and specific surface area of sediment particles. The desorption of benzo(a)pyrene from sediment was shown to be relatively rapid, with implications for the potential remobilisation of benzo(a)pyrene and similar compounds.
Maskaoui, K., Zhou, J.L., Hong, H.S. & Zhang, Z.L. 2002, 'Contamination by polycyclic aromatic hydrocarbons in the Jiulong River Estuary and Western Xiamen Sea, China', Environmental Pollution, vol. 118, no. 1, pp. 109-122.View/Download from: UTS OPUS or Publisher's site
The distribution of 16 polycyclic aromatic hydrocarbons (PAHs) was determined in water, sediment and pore water of the Jiulong River Estuary and Western Xiamen Sea, China. Total PAH concentrations varied from 6.96 to 26.9 µg/l in water, 591177 ng/g dry weight in surficial sediments, and 158949 µg/l in pore water. The PAHs were present in higher levels in pore water than in surface water, due possibly to higher concentrations of dissolved organic carbon or colloids with which the hydrophobic pollutants were strongly associated. Such a concentration gradient implies a potential flux of pollutants from sediment pore water to overlying water. The levels of PAHs in water and pore water were significantly higher than those found in 1998, suggesting recent inputs of these compounds into the area and re-working of sediment phase. The composition pattern of PAHs in the three phases was dominated by high molecular weight PAHs, in particular 5-ring PAHs. The salinity profile of dissolved PAHs suggested that they all behaved non-conservatively due to deviation from the theoretical dilution line. No correlation was found between PAH concentrations in sediment and those in pore water, and the correlation between the partition coefficients of PAHs and sediment organic carbon content was not significant, suggesting the complexity of the partition behaviour of PAHs. As a result of high PAH concentrations in water and pore water, it is likely that they may have caused mortality to certain exposed organisms.
Zhang, Z.L., Dai, M., Hong, H., Zhou, J.L. & YU, G. 2002, 'Dissolved insecticides and polychlorinated biphenyls in the Pearl River Estuary and South China Sea', Journal of Environmental Monitoring, vol. 4, no. 6, pp. 922-928.View/Download from: UTS OPUS or Publisher's site
Persistent organic pollutants (POPs) such as organochlorine (OCl) insecticides and polychlorinated biphenyls (PCB), together with the new generation of organophosphorus (OP) insecticides, are of global concern, due to their widespread occurrence, persistence, bioaccumulation and hormone disruption potential. This paper represents an attempt to study the source and transportation of such pollutants in estuarine and coastal environments as an integrated ecosystem, by determining the levels of 18 OCl insecticides, 21 PCB congeners, and 17 OP insecticides in the Pearl River Estuary and South China Sea. The total concentrations varied from 1261198 ng l-1 for OCl insecticides, 33.381064 ng l-1 for PCB congeners, and 4.446356 ng l-1 for OP insecticides in the Pearl River Estuary. In comparison, their levels in the South China Sea were significantly lower, varying from 57.09202 ng l-1 for OCl insecticides, 21.72144 ng l-1 for PCBs, and 1.27122 ng l-1 for OP insecticides, respectively. The predominance of -HCH in HCHs, and DDE in DDTs in all water samples was clearly observed, suggesting -HCH and DDE's resistance to further degradation. The PCBs were dominated by those with 36 chlorines. The distribution characteristic of OP insecticides shows that five compounds (methamidophos, dimethoate, malathion, dichlorvos and omethoate) accounted for 56% and 72% of the total OP insecticide concentration. The relationship between pollutant concentrations and salinity in the estuary showed that they were all removed during the mixing process, therefore behaving non-conservatively.
Zhang, Z.L., Hong, H.S., Zhou, J.L. & Yu, G. 2002, 'Occurrence and behaviour of organophosphorus insecticides in the River Wuchuan, southeast China', Journal of Environmental Monitoring, vol. 4, no. 4, pp. 498-504.View/Download from: UTS OPUS or Publisher's site
Organophosphorus (OP) insecticides are used worldwide, yet their persistence in the environment is not well understood. This paper summarises recent research on 17 OP insecticides in the River Wuchuan, an important catchment in China, by determining their concentrations in water, soil, sediment and plants by gas chromatography with flame photometric detection (GC-FPD). The concentrations of the total OP insecticides ranged from 92.77 to 229 ng l-1 in river water, 1.61 to 9.93 ng g-1 dry weight in soil, 1.24 to 7.56 ng g-1 dry weight in sediment and 75.28 to 326 ng g-1 dry weight in plants. There was a relatively high abundance of methamidophos, dichlorvos, malathion, omethoate and dimethoate in all water, soil, sediment and plant samples. On average, these five compounds collectively accounted for 64%, 71%, 71% and 54% of the total OP insecticide concentration in water, soil, sediment and plants, respectively, which was similar to the composition of OP insecticides in application formulations used in our study area and in China as a whole. The results therefore reflect the application pattern to some extent, and suggest that the sources of the OP insecticides are mainly from current usage. When compared with other areas, the levels of OP insecticides in the River Wuchuan were moderate. The animal and human risks from exposure to OP insecticides in water and plants were evaluated against relevant threshold values. The results therefore provide important information on the current contamination status of a key agricultural watershed in China, and point to the need for urgent action to control the use of some excessively applied and potentially persistent agrochemicals, such as methamidophos, omethoate and dimethoate.
Zhang, Z.L., Hong, H.S., Zhou, J.L., Dai, M.H., Maskaouib, K. & Chen, W.Q. 2002, 'Contamination by organochlorine pesticides in the estuaries of southeast China', Chemical Research in Chinese Universities, vol. 18, no. 2, pp. 153-160.
Persistent organic pollutants (POPs) such as organochlorine pesticides are of global concern due to their widespread occurrence and persistence. This paper reports recent research studying the distribution and fate of organochlorine pesticides in the Jiulong River, the Minjiang River and the Pearl River estuaries in Southeast China. Eighteen organochlorine pesticides were extracted from water, pore water and sediment samples, followed by analysis by GC-ECD. The results showed that the contamination levels were similar in these three estuaries. The levels of the total organochlorine pesticides in porewater were significantly higher than those in surface water, due to the high affinity of these hydrophobic compounds for sediment phase. Among the hexachlorocy-clohexane (HCH) compounds, -HCH was found to be the most important isomer. The analysis of 1, 1, 1-trichloro-2, 2-bis-chlorophyenyl-ethane (DDT) and its metabolites showed that 1, 1-dichloro-2 [o-chloropheny1]-2 [p-chlorophenyl] -ethylene (DDE) was dominant in the group.
Zhang, Z.L., Hong, H.S., Zhou, J.L., Yu, G., Chen, W. & Wang, X. 2002, 'Transport and fate of organochlorine pesticides in the River Wuchuan, Southeast China', Journal of Environmental Monitoring, vol. 4, no. 3, pp. 435-441.View/Download from: UTS OPUS or Publisher's site
Persistent organic pollutants (POPs) such as chlorinated pesticides are of global concern due to their widespread occurrence, persistence, bioaccumulation and toxicity to animals and human. This paper summarises recent research on 18 chlorinated pesticides in an important catchment in China, by determining their concentrations and behaviour in water, sediment, soil and plants. The concentrations of the total pesticides were in the ranges 187893 ng l-1 in river water, 8.53210 ng g-1 dry weight in soil, 2.6613.45 ng g-1 dry weight in river sediment, and 6512823 ng g-1 dry weight in plants. The predominance of -HCH as the major isomer of HCHs in all water, soil, sediment and plant samples was clearly observed, due to -HCHs resistance to biodegradation. On average -HCH accounted for 44%, 53%, 50%, and 46% of the total HCH concentration in water, soil, sediment and plant, respectively. Of the DDTs, DDE accounted for 48%, 43%, 53%, 55% of the total DDT, which suggested that DDT had been transformed to its metabolites, DDE and DDD, of which DDE was the more stable. The chlorinated pesticide levels in the River Wuchuan were generally below the guideline values in China, but some sites displayed levels in excess of EC Environmental Quality Standards for HCHs and DDTs. The results therefore provide important information on the current contamination status of a key agricultural watershed in China, and point to the need for urgent actions to evaluate the long-term fate and toxicity of such persistent compounds and an appropriate remediation strategy.
Zhou, J.L., Maskaoui, K., Qiu, Y.W., Hong, H.S. & Wang, Z.D. 2001, 'Polychlorinated biphenyl congeners and organochlorine insecticides in the water column and sediments of Daya Bay, China', Environmental Pollution, vol. 113, no. 3, pp. 373-384.View/Download from: UTS OPUS or Publisher's site
Samples of sub-surface water, suspended particulate matter (SPM) and surface sediments collected from Daya Bay, China have been analysed for 12 polychlorinated biphenyl (PCB) congeners and 18 organochlorine insecticides, using gas chromatography electron capture detection. Total PCB levels varied from 91.1 to 1355.3 ng l-1 in water and from 0.85 to 27.37 ng g-1 dry weight in sediments. The levels of total organochlorine insecticides were in the range 143.35104.8 ng l-1 in water and 2.4386.25 ng g-1 dry weight in sediment. None of the target compounds were detected in SPM. The levels of total hexachlorocyclohexanes in water varied from 35.5 to 1228.6 ng l-1, whilst in sediments they ranged from 0.32 to 4.16 ng g-1 dry weight. For the sum of dichlorodiphenyltrichloroethanes (DDTs), their levels were in the range 26.8975.9 ng l-1 in water, and 0.1420.27 ng g-1 dry weight in sediments. The distribution profiles of these contaminants in water and sediments suggest that there are a number of sources contributing to total contaminant burden in the bay, including soil runoffs, wastewater discharges, sewage outfalls and shipping activities. Ratios of DDT/(DDE+DDD) in the water and sediments indicate recent inputs of such chemicals into the bay. The results, therefore, provide important information on the current contamination status of a key aquacultural area in China, and point to the need for urgent actions to stop the use of persistent agrochemicals such as DDT and lindane.
Zhou, J.L., Salvador, S.M., Liu, Y.P. & Sequeira, M. 2001, 'Heavy metals in the tissues of common dolphins (Delphinus delphis) stranded on the Portuguese coast', The Science of the Total Environment, vol. 273, no. 1-3, pp. 61-76.View/Download from: UTS OPUS or Publisher's site
The concentrations of Hg, Sn, Cr, Zn, Ni, Co, Cd, Mn, Fe and Cu were determined in the liver, kidney and muscle of 24 common dolphins stranded on the Portuguese coast between 1995 and 1998. Nitric acid was used to extract the metals from the tissues for analysis by inductively-coupled plasma/atomic emission spectroscopy (ICP/AES). Those metals with relatively higher concentrations included Fe, Zn and Hg, particularly in liver. Other metals including Cr, Ni and Cd tended to show much lower levels, or were even undetected (e.g. Co). Different metals seemed to show different temporal trends, although due to substantial variations of the mean concentrations for each year obtained, such temporal pattern has to be studied further. Total Hg concentration in the kidney, muscle and particularly liver, were higher in females than in males. Total Hg concentrations in all the organs increased with body length of dolphins, whilst those of Zn and Cu in muscle decreased with dolphin length. A strong correlation was found between essential metals Zn and Cu in muscle, possibly resulting from sequestration of these metals by metallothionein. In addition, significant co-associations existed between the same metal (e.g. Hg, Sn and Zn) in different organs.
Sargent, C.J., Bowman, J.C. & Zhou, J.L. 2000, 'Levels of antifoulant irgarol 1051 in the Conwy Marina, North Wales', Chemosphere, vol. 41, no. 11, pp. 1755-1760.View/Download from: UTS OPUS or Publisher's site
Irgarol 1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine) is an antifouling agent used in paint formulations that are applied to the hulls of ships. A survey was carried out at Conwy Marina in North Wales to determine the levels of the herbicide over a period of three months. Liquid/liquid extraction was used to concentrate the analyte for quantitative analysis using gas chromatography/mass spectrometry (GC/MS) in the selected ion monitoring (SIM) mode. The concentrations of Irgarol 1051 in Conwy marina ranged from 7 to 543 ng/l, similar to the levels found in many other marinas, estuaries and ports in England, although much lower than those in Côte dAzur, France. The concentrations of Irgarol 1051 were not found to be influenced by salinity, pH or temperature, although there is a strong correlation between the average concentrations of Irgarol 1051 and the density of boating activity. At the levels found in the marina, it is possible that non-target photosynthetic inhibition could occur.
Zhou, J.L. & Liu, Y.P. 2000, 'Kinetics and equilibria of the interactions between diethylhexyl phthalate and sediment particles in simulated estuarine systems', Marine Chemistry, vol. 71, no. 1-2, pp. 165-176.View/Download from: UTS OPUS or Publisher's site
The sorption of diethylhexyl phthalate (DEHP) by sediment particles has been studied under simulated estuarine conditions, using freshwater and seawater samples collected from the Conwy Estuary, North Wales. The sorption process was rapid, reaching a sorption equilibrium within 6 h at a sediment concentration (SC) of 2.16 g l -1 . With an increase in SC, it took longer for the sorption equilibrium to be reached. The sorption equilibrium can be adequately described by the linear partition model at low equilibrium aqueous concentrations. The sorption of DEHP was enhanced in the presence of salts, due to the salting out effect, and a salting constant of 1.156 l mol -1 was obtained. The sorption coefficient of DEHP decreased with increasing SC, from 1.28 x 10 4 ml g -1 at 0.1 g l -1 SC to 6.75 x 103 ml g -1 at 14.66 g l -1 SC, due to the presence of colloidal particles in suspension which were able to bind DEHP. This third phase was quantified by measuring its dry weight, which was found to increase with increasing SC. The effect of colloids on DEHP sorption was studied by correcting the observed partition coefficients based on the concentration of colloid particles, and the true partition coefficients obtained (1.61 x 10 4 ± 1.29 x 10 3 ml g -1 ) were found to show much smaller variations than apparent partition coefficient (9.37 X 103 ± 2.12 x 10 3 ml g -1 ) at different SCs. Furthermore, the true organic carbon-normalised partition coefficients for the two sediments with different organic carbon content became similar and relatively independent of SCs. (C) 2000 Published by Elsevier Science B.V.
Zhou, J.L., Hong, H.S., Zhang, Z., Maskaoui, K. & Chen, W. 2000, 'Multi-phase distribution of organic micropollutants in Xiamen Harbour, China', Water research, vol. 34, no. 7, pp. 2132-2150.View/Download from: UTS OPUS
Xiamen Harbour, in the Xiamen Special Economic Zone of the Peoples Republic of China, was studied for its water and sediment quality, by determining the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs) and 18 organochlorine insecticides in water, suspended particulate matter (SPM), pore water and sediment samples from nine stations in the Harbour. Total PAH concentrations varied from 106 to 945 ng/l in water, <1 to 3548 ng/l in pore water, and 247 to 480 ng/g dry weight in surficial sediments. Total PCB levels varied from 0.1 to 1.7 ng/l in water, 2.7 to 34.8 ng/l in pore water, and <0.01 to 0.32 ng/g dry weight in sediments. The levels of all insecticides were in the range of 6.619.6 ng/l (water), 11.878.5 ng/l (pore water), and <0.010.58 ng/g dry weight (sediment). The levels of total hexachlorocyclohexane (HCHs) in sediments varied from <0.01 to 0.14 ng/g dry weight, and those of total DDTs were in the range of <0.010.06 ng/g dry weight. The micropollutants were present in higher levels in pore water than in surface water, due possibly to higher concentrations of dissolved organic carbon or colloids with which the hydrophobic pollutants are strongly associated. Such a concentration gradient implies a potential flux of pollutants from sediment pore water to overlying water. The levels of pollutants in sediments are one to several orders of magnitude lower than those found in 1993, suggesting their decreased inputs in recent years in the form of fresh and less contaminated material and possible degradation over a period of time. Further work is needed to quantify the levels of these contaminants in suspended particulate matter, which are currently below the limits of detection.
Zhou, J.L. 1999, 'Treating China's water crisis', Chemistry and Industry (London), no. 8, pp. 309-311.
Low rainfall in some areas, coupled with water wastage and high levels of pollution, is leading China to the brink of a major water crisis.
Biosorption of zinc ions by inactivated fungal mycelia was studied. Of the six fungal species, Rhizopus arrhizus, Mucor racemosus, Mycotypha africana, Aspergillus nidulans, Aspergillus niger and Schizosaccharomyces pombe, R. arrhizus exhibited the highest capacity (Q(max) = 213 mol g -1 dry weight). Further experiments with different cellular fractions of R. arrhizus showed that Zn was predominantly bound to cell-wall chitin and chitosan (Q(max) = 312 mol g -1 dry weight). Adsorption data were best modelled by the Langmuir isotherm, although they can be modelled by the Freundlich equation as well at relatively low aqueous concentrations. Biosorption generally decreased with increase in biosorbent particle size and its concentration. Low pH reduced Zn sorption, because of the strong competition from hydrogen ions for binding sites on fungi. The presence of ligands reduced metal uptake, chiefly by forming metal complexes of a less biosorbable nature.
Zhou, J.L., Fileman, T.W., Evans, S., Donkin, P., Readman, J.W., Mantoura, R.F.C. & Rowland, S. 1999, 'The partition of fluoranthene and pyrene between suspended particles and dissolved phase in the Humber Estuary: A study of the controlling factors', Science of the Total Environment, vol. 243-244, pp. 305-321.View/Download from: Publisher's site
Particle-water interactions are one of the most important mechanisms controlling the distribution and movement of hydrophobic organic chemicals such as polycyclic aromatic hydrocarbons (PAHs) in aquatic environments (e.g. estuaries and oceans). To accurately predict the transport and fates of hydrophobic contaminants in estuarine and coastal marine environments, the partition coefficient (K(p)) and organic carbon normalised partition coefficient (K(oc)) are widely used in various biogeochemical models. Such partition coefficients may be calculated from the so-called linear free energy relationships between K(p), K(oc) and more easily measured parameters such as the octanol-water partition coefficient (K(ow)). However K(p) and K(oc) values measured for real environmental samples of water and particles obtained from seasonal field surveys in the Humber Estuary, UK deviated from such ideals. For example, K(P) values showed no correlation with the fraction organic carbon content of particles (f(oc)) and instead of being constant, K(oc), values varied with f(oc). Both K(p) and K(oc) were 1-3 orders of magnitude higher than those predicted from the simple equilibrium-partitioning model, but were in good agreement with several other recently published field studies. To improve our understanding of PAH partitioning, the soot carbon (SC) content of particulate samples was measured so that the simple partition model can be extended to incorporate SC. The partition coefficients derived from the extended partition model are very close to the field K(p)s. The results suggest that PAHs associated with particles are in fact present in the form of soot and soot-like particles that are not subject to particle-water equilibrations. In other words, the PAHs on soot-like particles are extremely strongly bound and not influenced by further partitioning between the particles and water. However, there are still limitations with the extended partition model as it failed to simulate the ...
Zhou, J.L., Fileman, T.W., House, W.A., Long, J.L.A., Mantoura, R.F.C., Meharg, A.A., Osborn, D. & Wright, J. 1999, 'Fluxes of organic contaminants from the river catchment into, through and out of the Humber Estuary, UK', Marine Pollution Bulletin, vol. 37, no. 3-7, pp. 330-342.View/Download from: Publisher's site
This paper summarises the work done on the distribution and reactivity of organic contaminants (simazine, atrazine, lindane, fluoranthene, pyrene, PCB 77, PCB 118) in the Humber Estuary and associated major rivers, as part of the LOIS programme. The preliminary flux calculations show that the most important contributors of selected organic contaminants were the rivers Trent (45% of simazine, 20% of atrazine), Aire (30% of simazine and 33% of atrazine), Don (36 and 37% of fluoranthene and pyrene) and Ouse (18% of fluoranthene and pyrene). For lindane and PCBs, the Aire and Ouse were the key sources. The water flow in all the rivers shows strong seasonal variations, as do the contaminant concentrations. As a result, the mean daily fluxes of these contaminants displayed a strong seasonality. Annual mean concentrations of simazine and atrazine decreased by more than 50% over the period 1994-1995 in most of the rivers, probably as a result of their restricted use in the UK. Mass balance calculations show that the Humber is a sink for atrazine, lindane, PCB 77 and PCB 118, although the degree of removal is generally much lower for atrazine and lindane than for PCB 77 and PCB 118. Mass balance results also show that the Humber can either be a source of fluoranthene and pyrene (in the suspended particulate phase), or a sink (in the dissolved phase), although overall the Humber acts as sink. The budget exercise represents an attempt to quantify the input and output of selected organic contaminants from catchment to ocean. However, due to limited data and assumptions involved in calculations, the estimates should be considered as an order of magnitude approximation. Further improvement both in resolution and accuracy is required.
Zhou, J.L., Fileman, T.W., Evans, S., Donkin, P., Llewellyn, C., Readman, J.W., Mantoura, R.F.C. & Rowland, S.J. 1998, 'Fluoranthene and pyrene in the suspended particulate matter and surface sediments of the Humber estuary, UK', Marine Pollution Bulletin, vol. 36, no. 8, pp. 587-597.View/Download from: Publisher's site
As part of the UK-based Land-Ocean Interaction Study (LOIS) community programme, suspended particulate matter (SPM) and surface sediments have been collected from the Humber estuary, which is a large and complex estuarine system on the east coast of England fed by several rivers including the Trent and Ouse. The samples from four surveys were extracted and analysed to determine the levels of anthropogenic organic contaminants such as fluoranthene and pyrene. Their concentrations in SPM and surface sediments ranged from 44 to 1560 ng g -1 dry weight and 13-1969 ng g -1 dry weight, respectively, and displayed no strong seasonal variation. Mean fluoranthene and pyrene concentrations were higher in the Trent than in the Ouse for both SPM and sediment samples, and were elevated at a sewage outfall, suggesting a multiplicity of inputs for these two compounds. Fluoranthene and pyrene on SPM showed no correlation with salinity, although correlations with suspended solids concentrations (SSC) and particulate organic carbon (POC) have been confirmed.
The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment.
Zhou, J.L. & Rowland, S.J. 1997, 'Evaluation of the interactions between hydrophobic organic pollutants and suspended particles in estuarine waters', Water Research, vol. 31, no. 7, pp. 1708-1718.View/Download from: Publisher's site
Hydrophobic organic pollutants have a low aqueous solubility and tend to be adsorbed by suspended particulates, leading eventually to their storage in bed sediments. However, studies on the adsorption behaviour of extremely hydrophobic organic contaminants are scarce, and require more in-depth investigations. In this work, partition of two classes of hydrophobic contaminants was studied first in well-defined mineral particles covered with well-characterised humic substances, moving on to mixed end-member samples from the Tees, Tamar and Humber estuaries along a salinity gradient. Such chemicals partitioned more strongly to humic coatings than to estuarine particles, and the organic carbon normalised partition coefficient (K(oc)) values were well correlated with the aromaticity of organic coatings, suggesting that organic matter on estuarine particles consists of very complex mixtures with varying affinity for pollutant molecules. The partition coefficient (K(p)) for permethrin and bis(2-ethylhexyl) phthalate decreased with pH but increased with salinity, due to increased chemical hydrolysis in higher pH waters and decreased solubility in saline waters. The organic coatings on particles induced a more negative charge, due to the presence of uncomplexed carboxylic and phenolic hydroxyl groups. Estuarine suspended particles showed invariant electrophoretic mobility above 3 PSU salinity.
Zhou, J.L., Rowland, S.J., Mantoura, R.F.C. & Lane, M.C.G. 1997, 'Desorption of tefluthrin insecticide from soil in simulated rainfall runoff systems - kinetic studies and modelling', Water Research, vol. 31, no. 1, pp. 75-84.View/Download from: Publisher's site
The sorption and subsequent desorption from soil particles, of tefluthrin, a widely used soil-active pyrethroid insecticide, were studied in a simulated rainfall runoff system. Experimentation was facilitated by use of the 14 C-labelled compound. The desorption of such highly-hydrophobic organic compounds from soils has rarely been reliably determined previously. Sorption results showed that the partition coefficients (K(p) and K(oc)) were determined with good precision, although the resultant coefficients were shown to be underestimates of true adsorption to soil due to non-attainment of true equilibrium and the presence of colloidal material in the aqueous phase supernatants analysed. Once the adsorption slurries were diluted (30 ml of aqueous phase to 3.51) to simulate transport of soil to a larger water body after, heavy rainfall, kinetic studies, using a centrifugation method, indicated that the soil phase concentration decreased once more, whilst at the same time a biphasic re-equilibration process occurred in the aqueous phase. A direct particle counting method was used to rapidly and reproducibly measure desorption of 14 C-tefluthrin from soil under contrasting experimental conditions. Initial re-equilibration was shown to be rapid when soil-to-water ratios were changed significantly, temperature having a pronounced effect on this desorption. The results are important for the accurate modelling of tefluthrin behaviour in the environment.
Zhou, J.L., Fileman, T.W., Evans, S., Donkin, P., Mantoura, R.F.C. & Rowland, S.J. 1996, 'Seasonal distribution of dissolved pesticides and polynuclear aromatic hydrocarbons in the Humber estuary and Humber coastal zone', Marine Pollution Bulletin, vol. 32, no. 8-9, pp. 599-608.View/Download from: Publisher's site
The distribution of atrazine, 2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine (Irgarol 1051), lindane, malathion, fluoranthene and pyrene dissolved in the water column of the I-lumber Estuary and adjacent coastal zone was determined. Atrazine concentrations declined from the head (35-53 ng 1 -1 ) to the mouth (5-11 ng 1 -1 ) of the estuary; the highest concentrations were found in June. Lindane concentrations also declined through the estuary, although elevations were observed near a sewage outfall, especially in June and September. Irgarol concentrations typically peaked in April, then decreased in June before increasing again in September. The patterns of variation of fluoranthene and pyrene were similar to each other, suggesting common sources. Levels were similar throughout the estuary, with an exceptionally large elevation at a sewage outfall in June. Malathion concentrations were generally very low ( < 1-9 ng 1 -1 ). The concentrations of all compounds were lower off-shore than in the estuary, suggesting that the Humber catchment is a major source of organic micropollutants to the Humber coastal zone. Concentrations of atrazine and lindane were also elevated at stations close to the Wash, suggesting a contribution from rivers into the Wash.
Zhou, J.L., Rowland, S. & Mantoura, R.F.C. 1995, 'Partition of synthetic pyrethroid insecticides between dissolved and particulate phases', Water Research, vol. 29, no. 4, pp. 1023-1031.View/Download from: Publisher's site
A batch isotherm method is shown to be applicable to the determination of sorption equilibrium for the lipophilic pyrethroid insecticides between solution and sorbents. Adsorption of pyrethroids to glasswalls was significant and cannot be neglected. Sorption of lambdacyhalothrin on organically-coated montmorillonite was linear and much greater than on "pure" clay particles, consistent with a partition mechanism. The sorptive capacity of organic coatings was not constant, rather, it decreased with increasing polarity and decreasing aromaticity of organic sorbents, further suggesting hydrophobic bonding is the sorption mechanism. The results implied that the quantity as well as the quality of the organic matter on particle surfaces had to be characterised in order to better predict contaminant transport in aquatic and soil environments. It is therefore inappropriate to predict K oc from K ow or solubility with no consideration of the composition and structure of organic matter. © 1995.
Zhou, J.L., Rowland, S.J., Braven, J., Mantoura, R.F.C. & Harland, B.J. 1995, 'Tefluthrin sorption to mineral particles: Role of particle organic coatings', International Journal of Environmental Analytical Chemistry, vol. 58, no. 1-4, pp. 275-285.View/Download from: Publisher's site
The sorption of tefluthrin was studied on 'pure clay minerals and those that had been coated with aquatic humic substances over a mass percent carbon range of 0.02 to 2.15. Tefluthrin sorption onto humic-coated minerals was significantly greater than on to the clean minerals and increased with increasing quantities of sorbed humic substances. Humic acid, the most aromatic coating, was the strongest sorbent, followed by fulvic acid, hydrophilic macromolecular acid and natural coatings on estuarine suspended particles. This shows the significant impact of humic coatings on the sorptive capacity of mineral particles. The sorption was linear, also consistent with the operation of a partition process. The partition coefficient normalised to organic carbon (Koc) after deduction of the contribution from the clean mineral, ranged from 120000 to 770000 and was highest for the most aromatic humic acid fraction. © 1995, Taylor & Francis Group, LLC. All rights reserved.
Zhou, J.L., Rowland, S.J., Mantoura, R.F.C. & Harland, B.J. 1995, 'Influence of the nature of particulate organic matter on the sorption of cypermethrin: implications on KOCcorrelations', Environment International, vol. 21, no. 2, pp. 187-195.View/Download from: Publisher's site
The sorption of the pyrethroid insecticide, cypermethrin, on clean mineral particles, mineral particles coated with aquatic humic substances, and suspended particles from the Tees Estuary was studied. The sorption process was dominated by the organic carbon or organic matter on the particle surfaces, as shown by the significant increase in the sorptive capacity of montmorillonite after being coated with aquatic humic material. Humic acid, the most aromatic coating, was the strongest sorbent, followed by fulvic acid, hydrophilic macromolecular acid, then natural coatings on estuarine suspended particles. After deduction of the contribution from the clean mineral, K oc values ranged from 160 000 to 810 000; they decreased with increasing mass fraction organic carbon (f oc ) and increasing polarity in natural organic matter. A good correlation between K oc and f oc was found for both hydrophilic macromolecular acid coatings and natural coatings on estuarine particles, suggesting that hydrophilic macromolecular acid may be used to model organic coatings on estuarine suspended particles and their sorption behaviour. © 1995.
Zhou, J.L., Rowland, S., Fauzi, R., Mantoura, C. & Braven, J. 1994, 'The formation of humic coatings on mineral particles under simulated estuarine conditions-A mechanistic study', Water Research, vol. 28, no. 3, pp. 571-579.View/Download from: Publisher's site
The adsorption of three humic substances isolated from the River Dodder (Eire) and one commercial humic acid (Aldrich) by six minerals was studied and found to be influenced by mineral type, the nature of the humics and by the solution characteristics. Adsorption was heavily pH-dependent, with lower uptake at higher pH values due to increased ionization of the humic substances. The amount of humic substances adsorbed was in the order: Aldrich humic acid > Dodder humic acid > Dodder fulvic acid > Dodder hydrophilic macromolecular acid corresponding to a decreasing aromatic carbon content and increasing O/C ratio. Desorption experiments showed Aldrich humic acid was the most difficult to be desorbed, followed by Dodder humic acid, Dodder fulvic acid then Dodder hydrophilic macromolecular acid. Humic uptake was found to increase with ionic strength due to the neutralization of charges on both mineral surfaces and humic substances, and more importantly, the compression of diffuse double layers; this also showed that van der Waals attraction is an important part of the interactive forces between humic substances and mineral particles. The amount of humic substances adsorbed varied with mineral type, particle size and surface area, with aluminium oxide having the highest capacity. The effect of temperature on humic adsorption was shown to vary with humic type and two types of reaction mechanism have been proposed responsible for the humic-clay interactions. © 1994.
Zhou, J.L. & Banks, C.J. 1993, 'Mechanism of humic acid colour removal from natural waters by fungal biomass biosorption', Chemosphere, vol. 27, no. 4, pp. 607-620.View/Download from: Publisher's site
Removal of humic acid (HA) colour from natural waters by biosorption on Rhizopus arrhizus was studied. Experimental results demonstrated the dependence of adsorption on solution characteristics such as pH, ionic strength, concentration of metal ions and temperature. The observed effects were attributed to the pH dependence of humic acid solubility and surface charge of humic acid and fungal biomass. The biosorptive capacity of fungal cellular fractions was compared with the finding that chitin/chitosan was the major active component of R. arrhizus for humic acid uptake and this was confirmed by experiments on the effects of culture age, growth medium composition and biomass pre-treatment with caustic solutions on fungal sorptive capacity. Desorption experiments showed nearly all of the sorbed humic acid could be eluted, suggesting that the fungal biosorbents can be reused. © 1993.
The adsorption of a humic acid by eight fungal species was studied, of which R. arrhizus was studied in detail. The effects of solution pH, fungal species, biosorbent particle size, and solution ionic strength on the amount of humic acid adsorbed were examined and implications discussed. Experimental results showed that low solution pH and high ionic strength generally favoured biosorption while fungal biosorbents with a high chitin/chitosan content and small particle size had a higher total adsorptive capacity. The regenerability of biosorbents was also studied with the finding that 0.1N NaOH was the most efficient among those under investigation. © 1992.
The adsorption of humic acid by Rhizopus arrhizus obeyed the Freundlich equation describing heterogeneous surface energy adsorption, and was shown to be pH and biomass concentration dependent. The fungal cell wall chitin/chitosan component had the highest adsorption capacity, followed by cell wall, whole cell then protoplast. The effects of culture age, growth medium composition and biomass pre-treatment with NaOH were assessed in relation to adsorption efficiency and capacity. The presence of metal ions in solution increased humic acid removal by R.arrhizus, this was explained by the role of ions in bridging cell wall surface charge to humic acid surface charge. © 1992 Publications Division Selper Ltd.
Zhou, J.L. & Banks, C.J. 1991, 'Removal of humic acid fractions by Rhizopus arrhizus: Uptake and kinetic studies', Environmental Technology (United Kingdom), vol. 12, no. 10, pp. 859-869.View/Download from: Publisher's site
Humic acid components HFO-A and HPI-N were studied for their removal by Rhizopus arrhizus. The removal was stimulated by the presence of sucrose followed by pretreating biomass with formaldehyde or autoclaving. The presence of Cd 2+ ions and high ionic strength in solution was found to increase the adsorptive capacity of R. arrhizus for HPO-A and HPI-N. The uptake of HPO-A and HPI-N by R. arrhizus was biphasic in nature and generally a much slower process than heavy metal biosorption. The first phase was rapid and independent of metabolic energy while the second phase was slow and dependent on metabolic energy. The infrared spectra showed no chemical reaction has occurred between cell walls and adsorbates. Physical adsorption is therefore the main mechanism of humic removal by inactive R. arrhizus. © 1991 Publications Division Selper Ltd.
Ion exchange fractionation of humic acid yielded a highly coloured hydrophobic acid and hydrophilic neutral fractions; these were studied for their removal by Rhizopus arrhizus. The bioadsorptive capacity of the fungus was influenced by pH, biomass concentration and temperature. Adsorption energies were calculated and found to be within the physical adsorption range. The ability for complete desorption of both fractions further suggested that the predominant adsorptive mechanism was physical bonding. The fungal cell walls were shown to be totally responsible for the uptake. © 1991 Taylor and Francis Group, LLC.
Zhou, J.L. & Kiff, R.J. 1991, 'The uptake of copper from aqueous solution by immobilized fungal biomass', Journal of Chemical Technology & Biotechnology, vol. 52, no. 3, pp. 317-330.View/Download from: Publisher's site
The removal of cupric ions from aqueous solution by a biosorption column in which the Rhizopus arrhizus fungal biomass was immobilized in reticulated foam biomass support particles was studied. Solution pH was found to be crucial to copper uptake, with the optimum range being 67–70. The removal efficiency was usually higher at low influent copper concentration and long residence time. The presence of other cations and anions inhibited copper uptake in the following order: for the cations, Mn 2+ Zn 2+ > Cd 2+ > Mg 2+ > Ca 2+ ; for the anions, EDTA SO42 Cl . The biosorption process was fully reversible and regenerated columns showed undiminished performance. Copyright © 1991 Society of Chemical Industry
Zhou, J.L. & Banks, C.J. 1990, 'Fractionation of humic acid components by ion exchange chromatography', Environmental Technology (United Kingdom), vol. 11, no. 12, pp. 1147-1152.View/Download from: Publisher's site
Three kinds of resin adsorbents have been used to separate humic acid from water and inorganic salts and to fractionate these solutes into six compound classes. The multistep process consists of adsorption chromatography followed by cation and anion exchange chromatography, rotary vacuum evaporation, desalting and crystallisation. It recovered 96% of the total mass of humic acid from 2 litres of 400mg 1 humic acid solution. © 1990 Taylor and Francis Group, LLC.
Zhou, J. 2012, 'Sampling of humic and colloidal phases in liquid samples' in Janusz Pawliszyn (ed), Comprehensive Sampling and Sample Preparation, Elsevier, Amsterdam, pp. 335-348.View/Download from: UTS OPUS
Zhang, Z., Grover, D.P. & Zhou, J.L. 2009, 'Monitoring of pharmaceutical residues in sewage effluents' in Nollet, L.M.L. (ed), Analysis of Endocrine Disrupting Compounds in Food, Blackwell, Iowa, pp. 315-342.View/Download from: UTS OPUS
Zhou, J. 2011, 'Growth responses and phytoremediation characteristics of Mirabilis jalapa L. in benzo[a]pyrene and pyrene co-contaminated soils', Proceedings for the Conference on Advances in Computer Science, Intelligent System and Environment, Conference on Advances in Computer Science, Intelligent System and Environment, Springer-Verlag Berlin Heidelberg, Guangzhou, PEOPLES R CHINA, pp. 397-403.View/Download from: UTS OPUS or Publisher's site