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Associate Professor Richard Lim

Biography

Richard Lim is an aquatic ecotoxicologist. His research interests are in the ecotoxicology of pesticides, heavy metals, persistent organic chemicals, endocrine disrupting chemicals and salinity with a focus on assessing the impacts and risks of these contaminants and their mixtures in aquatic systems. It focuses on anthropogenic impacts of agricultural and mining activities as well as urbanisation including sewage effluent on these ecosystems.

His research involves the use of a suite of bioassays spanning a range of ecological scales from in vitro and in vivo bioassays to population and community studies in the laboratory, mesocosms and field.

His research also encompasses a range of test organisms from bacteria to algae and aquatic plants to invertebrates and fish. Richard also has expertise in limnology particularly in stream ecology and pollution studies in relation to stream health, ecology of wetlands including ricefields, and zooplankton taxonomy.

The information generated from his research contributes to an understanding of how anthropogenic activities impact on the health of ecosystems leading to development of appropriate management strategies.

In collaboration with researchers in UTS Environmental Engineering his research includes assessing the ability of innovative effluent treatment technologies in removing toxicants using an effects-based approach.

Professional

Membership to Professional Societies
Australian Society for Limnology (Life member)Australasian Society for Ecotoxicology

Image of Richard Lim
Associate of the Faculty, School of Life Sciences
Associate Member, Centre for Environmental Sustainability
Associate Member, Centre for Technology in Water and Wastewater
BSc (Hons) (UM), MSc (UM), PhD (Waterloo)
 
Phone
+61 2 9514 8297
Fax
+61 2 9514 4079
Room
CB07.06.021

Research Interests

Ecotoxicology of pesticides
Impact of endocrine disrupting chemicals on the aquatic fauna
Impact of mining on stream macroinvertebrates
Stream pollution studies
Ecology of wetlands (lakes and rivers)
Zooplankton taxonomy

Limnology
Ecotoxicology
General biology and ecology
Environmental engineering

Chapters

Rahman, M.A., Lim, R.P. & Hasegawa, H. 2012, 'Biodegradable chelating ligands for iron and arsenic bioavailability and uptake in rice (Oryza sativa L.)' in Ng, J.C., Noller, B.N., Naidu, R., Bundschuh, J. & Bhattacharya, P. (eds), Understanding the Geological and Medical Interface of Arsenic, CRC Press, AK Leiden, The Netherlands, pp. 394-396.
Biodegradable chelating ligands Ethylenediaminedisuccinic acid (EDDS), Hydroxyiminodisuccinic acid (HIDS) and Methylglycindiacetic Acid (MGDA) for iron (Fe) and arsenic (As) bioavailability and uptake were investigated using hydroponic rice (Oryza sativa L.). The growth of rice seedlings decreased significantly (P < 0.05) with increasing pH. The highest growth was observed at pH 7 which was related to Fe concentrations in roots and shoots. As and Fe uptake in rice roots was increased by significantly (P < 0.05) by EDDS and HIDS, while their translocation to shoots were not influenced by the ligands. EDDS and HIDS were more efficient in As and Fe uptake than MGDA indicating that EDDS and HIDS would be good ligands for the increase of Fe uptake and Fe phytoextraction

Conferences

Doyle, C., Barker, J., Lim, R.P. & Gray, L.E. 2003, 'Reproductive morphology of male mosquitofish (gambusia holbrooki) inhabiting sewage-contaminated waters in the South Creek catchment on the Hawkesbury-Nepean River', Proceedings of Chemicals of Concern in Water Speciality Conference 2003, Australian Water Assocaition & International Water Association, Sydney, Australia, pp. 1-10.
Brennan, E.L., Lim, R.P., Doyle, C. & Laginestra, E. 2003, 'The use of Poecilliids to assess the endocrine disrupting capacity of waters with reference to the mosquitofish inhabiting water bodies in the Sydney Olympic Park, Homebush Bay.', Proceedings of Chemicals of Concern in Water Speciality Conference 2003, Australian Water Association & International Water Association, Sydney, Australia, pp. 1-8.

Journal articles

Rahman, M.A., Rahman, M.M., Reichman, S.M., Lim, R.P. & Naidu, R. 2014, 'Heavy metals in Australian grown and imported rice and vegetables on sale in Australia: Health hazard', Ecotoxicology and Environmental Safety, vol. 100, no. 1, pp. 53-60.
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Dietary exposure to heavy metals is a matter of concern for human health risk through the consumption of rice, vegetables and other major foodstuffs. In the present study, we investigated concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) in Australian grown and imported rice and vegetables on sale in Australia. The mean concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in Australian grown rice were 7.5?gkg-1, 21?gkg-1, 144?gkg-1, 2.9mgkg-1, 24.4mgkg-1, 166?gkg-1, 375?gkg-1, and 17.1mgkg-1 dry weight (d. wt.), respectively. Except Cd, heavy metal concentrations in Australian grown rice were higher than Bangladeshi rice on sale in Australia. However, the concentrations of Cd, Cr, Cu, and Ni in Indian rice on sale in Australia were higher than Australian grown rice. The concentrations of Cu and Ni in Vietnamese rice, and that of Cd, Cr, Cu, Ni, and Pb in Thai rice on sale in Australia were also higher than Australian grown rice. Heavy metal concentrations in Pakistani rice on sale in Australia were substantially lower than that in Australian grown rice. In Australian grown rice varieties, the concentrations of heavy metals were considerably higher in brown rice varieties than white rice varieties, indicating Australian brown rice as a potential source of dietary heavy metals for Australian consumers. The mean concentrations of heavy metals in Australian grown and Bangladeshi vegetables on sale in Australia were also determined. Some of the Australian grown and Bangladeshi vegetables contained heavy metals higher than Australian standard maximum limits indicating them as potential sources of dietary heavy metals for Australian consumers. Further investigation is required to estimate health risks of heavy metals from rice and vegetables consumption for Australian consumers. &copy; 2013 Elsevier Inc.
Chen, Z., Ngo, H.H., Guo, W., Lim, R., Wang, X.C., O'Halloran, K., Listowski, A., Corby, N. & Miechel, C. 2014, 'A comprehensive framework for the assessment of new end uses in recycled water schemes', Science of the Total Environment, vol. 470-471, pp. 44-52.
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Nowadays, recycled water has provided sufficient flexibility to satisfy short-term freshwater needs and increase the reliability of long-term water supplies in many water scarce areas, which becomes an essential component of integrated water resources management. However, the current applications of recycled water are still quite limited that are mainly associated with non-potable purposes such as irrigation, industrial uses, toilet flushing and car washing. There is a large potential to exploit and develop new end uses of recycled water in both urban and rural areas. This can greatly contribute to freshwater savings, wastewater reduction and water sustainability. Consequently, the paper identified the potentials for the development of three recycled water new end uses, household laundry, livestock feeding and servicing, and swimming pool, in future water use market. To validate the strengths of these new applications, a conceptual decision analytic framework was proposed. This can be able to facilitate the optional management strategy selection process and thereafter provide guidance on the future end use studies within a larger context of the community, processes, and models in decision-making. Moreover, as complex evaluation criteria were selected and taken into account to narrow down the multiple management alternatives, the methodology can successfully add transparency, objectivity and comprehensiveness to the assessment. Meanwhile, the proposed approach could also allow flexibility to adapt to particular circumstances of each case under study. &copy; 2013 Elsevier B.V.
Chen, Z., Ngo, H.H., Guo, W., Pham, T.T.N., Lim, R., Wang, X.C., Miechel, C., Halloran, K.O.'., Listowski, A. & Corby, N. 2014, 'A new optional recycled water pre-treatment system prior to use in the household laundry', Science of the Total Environment, vol. 476-477, pp. 513-521.
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With a constantly growing population, water scarcity becomes the limiting factor for further social and economic growth. To achieve a partial reduction in current freshwater demands and lessen the environmental loadings, an increasing trend in the water market tends to adopt recycled water for household laundries as a new recycled water application. The installation of a small pre-treatment unit for water purification can not only further improve the recycled water quality, but also be viable to enhance the public confidence and acceptance level on recycled water consumption. Specifically, this paper describes column experiments conducted using a 550. mm length bed of zeolite media as a one-dimensional flow reactor. The results show that the zeolite filter system could be a simple low-cost pre-treatment option which is able to significantly reduce the total hardness level of recycled water via effective ion exchange. Additionally, depending on the quality of recycled water required by end users, a new by-pass controller using a three-level operation switching mechanism is introduced. This approach provides householders sufficient flexibility to respond to different levels of desired recycled water quality and increase the reliability of long-term system operation. These findings could be beneficial to the smooth implementation of new end uses and expansion of the potential recycled water market. The information could also offer sound suggestions for future research on sustainable water management and governance. &copy; 2014 Elsevier B.V.
Rahman, M.A., Hogan, B., Duncan, E., Doyle, C., Krassoi, R., Rahman, M.M., Naidu, R., Lim, R.P., Maher, W. & Hassler, C. 2014, 'Toxicity of arsenic species to three freshwater organisms and biotransformation of inorganic arsenic by freshwater phytoplankton (Chlorella sp CE-35)', ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, vol. 106, pp. 126-135.
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Rahman, M.A., Rahman, M.M., Reichman, S.M., Lim, R.P. & Naidu, R. 2014, 'Arsenic speciation in australian-grown and imported rice on sale in Australia: Implications for human health risk', Journal of Agricultural and Food Chemistry, vol. 62, no. 25, pp. 6016-6024.
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Rice is an important route of arsenic (As) exposure to humans, especially populations with rice-based diets. Human health risk of As varies greatly with rice variety and country of origin. The purpose of the present study was to determine total and speciated As in Australian-grown and imported rice on sale in Australia to assess their health risk to consumers. The total As (tAs) concentrations in Australian-grown organic brown, medium grain brown, and organic white rice were 438 &plusmn; 23, 287 &plusmn; 03, and 283 &plusmn; 18 ?g kg-1 dry weight (d wt), respectively. In Bangladeshi, Indian, Pakistani, and Thai rice imported and on sale in Australia, tAs concentrations were 56 &plusmn; 05, 92 &plusmn; 10, 82 &plusmn; 06 and 172 &plusmn; 24 ?g kg-1, respectively. Asian rice contained mainly inorganic As (iAs; 86-99%), whereas 18-26% of the tAs in Australian-grown rice was dimethylarsinic acid (DMA). Relatively higher concentrations of tAs in Australian-grown rice than that in imported rice of Asian origin suggest that Australian-grown rice may be a health risk for the consumers. It was estimated that Australian-grown organic brown rice can contribute up to 98% of the FAO/WHO recommended maximum tolerable daily intake limit of iAs (2.1 ?g kg-1 body wt day -1) for Asian immigrants. However, other Australian consumers including European immigrants are unlikely to be at risk to As from rice diets due to their lower rice consumption rates than that of Asian immigrants. The risk assessment showed that imported rice on sale in Australia was likely to pose a lower health risk to consumers than Australian-grown rice. &copy; 2014 American Chemical Society.
Scott, P.D., Bartkow, M., Blockwell, S.J., Coleman, H.M., Khan, S.J., Lim, R., McDonald, J.A., Nice, H., Nugegoda, D., Pettigrove, V., Tremblay, L.A., Warne, M.S.J. & Leusch, F.D.L. 2014, 'A National Survey of Trace Organic Contaminants in Australian Rivers', Journal of Environment Quality, vol. 43, no. 5, pp. 1702-1702.
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Mowe, M.A.D., Mitrovic, S.M., Lim, R.P., Furey, A. & Yeo, D.C.J. 2014, 'Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors', Journal of Limnology, vol. 73, no. AoP.
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Phyu, Y.L., Palmer, C.G., Warne, M.S.J., Dowse, R., Mueller, S., Chapman, J., Hose, G.C. & Lim, R.P. 2013, 'Assessing the chronic toxicity of atrazine, permethrin, and chlorothalonil to the cladoceran Ceriodaphnia cf. dubia in laboratory and natural river water', Archives of Environmental Contamination and Toxicology, vol. 64, no. 3, pp. 419-426.
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The majority of ecotoxicological data are generated from standard laboratory-based experiments with organisms exposed in nonflowing systems using highly purified water, which contains very low amounts of dissolved organic matter and suspended particulates. However, such experimental conditions are not ecologically relevant. Thus, there is a need to develop more realistic approaches to determining toxicity, including both lethal and sublethal effects. This research provides information on the effect of natural water constituents, such as suspended particulates and dissolved organic matter, in river water (RW) on the chronic toxicity (7-day reproductive impairment) of the pesticides atrazine, chlorothalonil, and permethrin to the freshwater cladoceran Ceriodaphnia cf. dubia. Standard bioassays were conducted under standard laboratory and more environmentally realistic conditions (using RW). The 7-day IC25 (reproduction impairment) values of atrazine, chlorothalonil, and permethrin to C. cf. dubia ranged from 862.4 to >1000, 51.3 to 66.4, and 0.19 to 0.23 ?g/L, respectively. Using the Globally Harmonized System of Classification and Labelling of Chemicals, atrazine is classified as moderately to highly toxic, whereas permethrin and chlorothalonil were both highly toxic. The presence of dissolved organic matter and suspended particles in natural RW did not significantly (p > 0.05) change the toxicity of any of the pesticides to C. cf. dubia compared with that tested in laboratory water (LW). For the tested pesticides, toxicity testing in LW provided an adequate estimate of the hazard posed. &copy; 2012 Springer Science+Business Media New York.
Korbel, K.L., Hancock, P.J., Serov, P., Lim, R.P. & Hose, G.C. 2013, 'Groundwater Ecosystems Vary with Land Use across a Mixed Agricultural Landscape', JOURNAL OF ENVIRONMENTAL QUALITY, vol. 42, no. 2, pp. 380-390.
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Korbel, K.L., Lim, R.P. & Hose, G.C. 2013, 'An inter-catchment comparison of groundwater biota in the cotton-growing region of north-western New South Wales', Crop and Pasture Science, vol. 64, no. 11-12, pp. 1195-1208.
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Groundwater is essential to crop production in many parts of the world, and the provision of clean groundwater is dependent on healthy groundwater ecosystems. To understand better the functioning of groundwater ecosystems, it is necessary to understand how the biota responds to environmental factors, and so distinguish natural variation from human induced changes. This study compares the groundwater biota of the adjacent Gwydir and Namoi River alluvial aquifers, both in the heartland of Australia's cotton industry, and investigates the relative importance of environmental, anthropogenic, geological, and evolutionary processes on biotic distribution. Distinct differences in biotic assemblages were recorded between catchments at a community level. However, at a functional level (e.g. microbial activity, stygofauna abundances and richness) both ecosystems were similar. The distribution of biota in both catchments was influenced by similar environmental variables (e.g. geology, carbon availability, season, and land use). Broad trends in biotic distribution were evident: stygofauna responded most strongly to geological variables (reflecting habitat) and microbes to water quality and flow. Agricultural activities influenced biota in both catchments. Although possessing different taxa, the groundwater ecosystems of the two aquifers were functionally similar and responded to similar environmental conditions. &copy; 2013 CSIRO.
Rahman, M.A., Hasegawa, H., Rahman, M.M., Maki, T. & Lim, R.P. 2013, 'Effect of iron (Fe2+) concentration in soil on arsenic uptake in rice plant (Oryza sativa L.) when grown with arsenate [As(V)] and dimethylarsinate (DMA)', Water, Air, and Soil Pollution, vol. 224, no. 7.
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Being predominant inorganic arsenicals, methylarsenicals also occur in anaerobic paddy soils. Therefore, this study investigated the influence of Fe2+ concentrations and arsenic speciation [arsenate (As(V)) and dimethylarsinate (DMA)] in paddy soils on arsenic uptake in rice plant. Rice seedlings were grown in soil irrigated with a Murashige and Skoog (MS) growth solution containing As(V) or DMA with or without 1.8 mM Fe2+ in excess to the background concentration of total iron (0.03 mM) in the soil. Arsenic concentration in rice roots increased initially and then decreased gradually when the seedlings were grown with excess Fe2+ and As(V). In contrast, arsenic concentration in the roots increased steadily (P < 0.01) when the seedlings were grown without excess Fe2+ and As(V). When the form of the arsenic was DMA, total arsenic (tAs) concentration in rice roots increased gradually (P < 0.01) and was not affected by the addition of excess Fe2+ in the soil. When rice seedlings were grown with As(V), tAs concentration in rice roots and shoots increased steadily (P < 0.01) for gradual increase of Fe2+ concentrations in soil. However, tAs concentration in roots and shoots was independent of Fe2+ concentrations in soil when the form of arsenic was DMA. The tAs concentrations in rice shoots also increased significantly (P < 0.01) with increasing exposure time for both As(V) and DMA. Thus, Fe2+ concentrations in soil affect arsenic uptake in rice plant depending on the speciation of arsenic. &copy; 2013 Springer Science+Business Media Dordrecht.
Mohammed Abdul, J., Colville, A.E., Lim, R.P., Vigneswaran, S. & Kandasamy, J.K. 2012, 'Use of duckweed (Lemna disperma) to assess the phytotoxicity of the products of Fenton oxidation of metsulfuron methyl', Ecotoxicology And Environmental Safety, vol. 83, pp. 89-95.
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Because of pressure on water supplies world-wide, there is increasing interest in methods of remediating contaminated ground waters. However, with some remediation processes, the breakdown products are more toxic than the original contaminant. Organic matter and salinity may also influence degradation efficiency. This study tested the efficiency of Fenton oxidation in degrading the sulfonylurea herbicide metsulfuron methyl (MeS), and tested the reaction products for phytotoxicity with the Lemna (duckweed) bioassay. The efficiency of degradation by Fenton&acirc;s reagent (Fe2&Atilde;&frac34; &Acirc;&frac14;0.09 mM; H2O2&Acirc;&frac14;1.76mM, 4 h) decreased with increasing initial MeS concentration, from 98% with 5 mg/L MeS, to 63% with 70 mg/L MeS. Addition of NaCl (10 mM) and organic matter (humic acid at 0.2 and 2.0 mg C/L as Total Organic Carbon) reduced the efficiency of degradation at low initial MeS concentrations (5 and 10mg/L), but had no effect at high concentrations. The residual Fenton&acirc;s reagent after Fenton&acirc;s oxidation was toxic to Lemna. After removal of residual iron and H2O2, the measured toxicity to Lemna in the treated samples could be explained by the concentrations of MeS as measured by HPLC/UV detection, so there was no evidence of additional toxicity or amelioration due to the by-products or formulation materials.
Cortez, D.P., Growns, I.O., Mitrovic, S.M. & Lim, R.P. 2012, 'Effects of a gradient in river regulation on the longitudinal trends in water quality and benthic algal and macroinvertebrate assemblages in the Hunter River, Australia', Marine and Freshwater Research, vol. 63, no. 6, pp. 494-504.
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River regulation impacts lotic ecosystem processes; however, the effect of a gradient of regulation on these attributes has rarely been studied. This study examined the effects of a river regulation gradient on longitudinal trends in water quality and benthic algal and macroinvertebrate assemblages in three tributaries of the Hunter River, New South Wales, Australia. Longitudinal patterns were expected to differ across rivers, with recovery being proportional to its regulation gradient. Significant differences in longitudinal trends were tested using permutational multivariate analysis of variance (PERMANOVA) through exploration of the river by distance from source interaction. Multi-dimensional scaling (MDS) ordination plots identified sites responsible for any significant interaction observed. Similarity percentage analysis (SIMPER) analyses identified variables/taxa responsible for differences at sites below dams. BEST analyses identified environmental variables best explaining biological assemblage patterns. Significant differences in longitudinal trends were observed for all attributes. Increases in the regulation gradient most affected macroinvertebrate assemblages, followed by water quality and benthic algal assemblages respectively. Downstream recovery was absent in the heavily regulated river at its most downstream site, whereas recovery was observed on corresponding sites of the moderately regulated river. The study suggests that a gradient in river regulation increases the magnitude of disruption of lotic ecosystems, with recovery dependent on this gradient. &copy; 2012 CSIRO.
Davie, A.W., Mitrovic, S.M. & Lim, R.P. 2012, 'Succession and accrual of benthic algae on cobbles of an upland river following scouring', Inland Waters, vol. 2, no. 2, pp. 89-100.
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Flow releases from dams can be used to scour benthic algae, simulating the effects of natural spates and maintaining benthic algae in an early successional stage for increased grazer palatability. The timing of releases needs to consider the natural periodicity of flow events and the speed of regrowth and community succession changes. We studied benthic algal regrowth and succession using manipulative field experiments during summer and winter in the upland regulated Severn River, New South Wales, Australia. Benthic algal biomass accrual as chlorophyll a and community changes were determined after artificially scoured cobbles were returned to the river. In summer, algal biomass and diversity on scoured cobbles took 2 weeks to return to levels similar to reference cobbles and 5 weeks in winter. Chlorophyll a during summer was initially 0.24 &plusmn; 0.06 mg m-2 on scoured cobbles, but by day 16 had increased to 9.74 &plusmn; 1.97 mg m-2 and was no longer significantly different from reference cobbles. In winter, chlorophyll a was initially 0.47 &plusmn; 0.13 mg m-2 on scoured cobbles, but by day 37 had increased to 44.7 &plusmn; 10.9 mg m-2 and was no longer significantly different from reference cobbles. Peak chlorophyll a accrual during summer and winter was 1.64 and 2.63 mg m-2 d-1, respectively. Early succession in both experiments was dominated by diatoms such as Cocconeis, Synedra, and Fragilaria. A proliferation of the filamentous green alga Stigeoclonium was indicative of a late succession community. The implications for flow management based on resetting of benthic algae by scouring in riffle reaches of rivers are discussed. &copy; International Society of Limnology 2012.
Phyu, Y.L., Palmer, C.G., Warne, M.S.J., Hose, G.C., Chapman, J.C. & Lim, R.P. 2011, 'A comparison of mixture toxicity assessment: Examining the chronic toxicity of atrazine, permethrin and chlorothalonil in mixtures to Ceriodaphnia cf. Dubia', Chemosphere, vol. 85, no. 10, pp. 1568-1573.
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Pesticides predominantly occur in aquatic ecosystems as mixtures of varying complexity, yet relatively few studies have examined the toxicity of pesticide mixtures. Atrazine, chlorothalonil and permethrin are widely used pesticides that have different modes of action. This study examined the chronic toxicities (7-d reproductive impairment) of these pesticides in binary and ternary mixtures to the freshwater cladoceran Ceriodaphnia cf. dubia. The toxicity of the mixtures was compared to that predicted by the independent action (IA) model for mixtures, as this is the most appropriate model for chemicals with different modes of action. Following this they were compared to the toxicity predicted by the concentration addition (CA) model for mixtures. According to the IA model, the toxicity of the chlorothalonil plus atrazine mixture conformed to antagonism, while that of chlorothalonil and permethrin conformed to synergism. The toxicity of the atrazine and permethrin mixture as well as the ternary mixture conformed to IA implying there was either no interaction between the components of these mixtures and/or in the case of the ternary mixture the interactions cancelled each other out to result in IA. The synergistic and antagonistic mixtures deviated from IA by factors greater than 3 and less than 2.5, respectively. When the toxicity of the mixtures was compared to the predictions of the CA model, the binary mixture of chlorothalonil plus atrazine, permethrin plus atrazine and the ternary mixture all conformed to antagonism, while the binary mixture of chlorothalonil plus permethrin conformed to CA. Using the CA model provided estimates of mixture toxicity that did not markedly underestimate the measured toxicity, unlike the IA model, and therefore the CA model is the most suitable to use in ecological risk assessments of these pesticides. &copy; 2011 Elsevier Ltd.
Rawson, C.A., Lim, R.P., Tremblay, L.A., Warne, M.S.J., Ying, G.-.G., Laginestra, E. & Chapman, J.C. 2010, 'Benthic macroinvertebrate assemblages in remediated wetlands around Sydney, Australia', Ecotoxicology, vol. 19, no. 8, pp. 1589-1600.
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To investigate potential high organisational level impacts of persistent organic pollution in the wetlands in the Sydney Olympic Park (SOP) remediated site, the benthic macroinvertebrate assemblages of seven wetlands within SOP and two off-site reference wetlands were examined. Sediment cores were collected, stained and preserved from each study site and the macroinvertebrates identified to the appropriate taxonomic level (Class, Order, Family, Subfamily). Data were analysed for taxon richness and macroinvertebrate abundance and multivariate techniques were used to identify chemical/physical characteristics of the sediment, which were important influences on the differences in the assemblage between study sites. Macroinvertebrate abundance was highly variable between study sites and taxon richness was low across all sites. Oligochaetes, nematodes, ostracods and chironomids were the most common taxa found and were the most important in influencing differences between the macroinvertebrate assemblages among the study sites. Sediment grain size and chemical characteristics of the sediments (RPAH, RPCB, TCDDeq and heavy metal concentrations) were important in separating the study sites based on taxon richness and abundance. Canonical correspondence analysis separated the macroinvertebrate assemblages at newly two created wetlands from those at other study sites including the urban reference sites. Increased sediment POP contamination (particularly as measured TCDDeq and RDDT concentrations) is a likely contributor in excluding pollution sensitive taxa and, therefore, alterations to benthic macroinvertebrate assemblages. Further, the influence of TOC suggests the significance of catchment inputs in contributing to changes in macroinvertebrate assemblage. The SOP remediation led to the establishment of wetlands with benthic communities representative of those expected in urban wetlands. &copy; Springer Science+Business Media, LLC 2010.
Leusch, F., De Jager, C., Levi, Y., Lim, R.P., Puijker, L., Sacher, F., Tremblay, L., Wilson, V. & Chapman, H.D. 2010, 'Comparison Of Five In Vitro Bioassays To Measure Estrogenic Activity In Environmental Waters', Environmental Science & Technology, vol. 44, no. 10, pp. 3853-3860.
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Bioassays are well established in the pharmaceutical industry and single compound analysis, but there is still uncertainty about their usefulness in environmental monitoring. We compared the responses of five bioassays designed to measure estrogenic acti
Ying, G.-.G., Rawson, C.A., Kookana, R.S., Peng, P.-.A., Warne, M.S.J., Tremblay, L.A., Laginestra, E., Chapman, J.C. & Lim, R.P. 2009, 'Contamination and screening level toxicity of sediments from remediated and unremediated wetlands near Sydney, Australia', Environmental Toxicology and Chemistry, vol. 28, no. 10, pp. 2052-2060.
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The present study assessed contamination and toxicity of sediments from seven remediated and remnant wetland sites within Sydney Olympic Park, Australia, and four unremediated sites adjacent to its boundary using chemical analysis and a luminescent bacterial biosensor assay (Escherichia coli). Concentrations of metals (Pb, Cr, Cu, Ni, Zn, Cd, and As) and persistent organic chemicals (DDT and its metabolites, dichlorodiphenyldichloroethane and dichlorodiphenyldichloroethylene; polycyclic aromatic hydrocarbons; polychlorinated biphenyls; and polychlorinated dibenzo-p-dioxins and dibenzofurans) in sediments and their pore-water samples were determined. Zinc concentrations were the highest of the metals in the sediments (84-618 mg/kg), and at eight sites, metal concentrations in sediments exceeded the Australian ecological trigger values for Pb, Zn, and Ni. Concentrations of organic contaminants in the sediments exceeded the trigger values at all 11 sites for DDTs, at 6 sites for polycyclic aromatic hydrocarbons, and 5 sites for polychlorinated biphenyls. Sediment samples from the four unremediated sites outside the Sydney Olympic Park had dioxin concentrations greater than 200 pg (toxic equivalency per gram). The same four sites were identified as contaminated in pore-water toxicity tests with the luminescent biosensor, generally consistent with the bioavailable fractions of the contaminants (pore-water and Tenax&reg; extraction data), as well as dioxin levels, in the sediments. Preliminary toxicity identification and evaluation tests of the pore water from the four sites outside the park demonstrated that organic contaminants were the main cause of toxicity to E. coli, with no evidence that metals contributed to the toxicity of the pore water. &copy; 2009 SETAC.
Rawson, C.A., Tremblay, L.A., Warne, M.S.J., Ying, G.-.G., Kookana, R., Laginestra, E., Chapman, J.C. & Lim, R.P. 2009, 'Bioactivity of POPs and their effects in mosquitofish in Sydney Olympic Park, Australia', Science of the Total Environment, vol. 407, no. 12, pp. 3721-3730.
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The site of the 2000 Olympic Games (Sydney Olympic Park (SOP), Sydney, Australia) was contaminated by persistent organic pollutants (POPs) prior to remediation in the 1990s. This study investigates the bioactivity of POPs in the sediment and water of wetlands across SOP by in vitro 2,3,7,8-TCDD equivalence (TCDDeq) measurement (H4IIE cell line bioassay). Further, it examines whether disturbance of these sediments is likely to mobilise ligands for this receptor into the water column. Exposure to aryl hydrocarbon receptor (AhR) ligands was measured in vivo using hepatic cytochrome P4501A (CYP1A) induction (EROD) in the mosquitofish (Gambusia holbrooki). Aqueous TCDDeq ranged from 0.013 to 0.057&nbsp;pM in SOP wetlands which was significantly (p < 0.05) less that in urban reference sites. These concentrations were not correlated to physical or chemical characteristics of the wetlands. In the sediments, TCDDeq ranged from 0.0016 to 7.06&nbsp;?g/kg and these were not significantly (p ? 0.05) different to that measured in urban reference sites. Simulated disturbance of small quantities of sediment in water samples significantly (p < 0.05) increased the levels of TCDDeq measured in the water. Sediment TCDDeq was correlated to sediment ?PAH concentration in 2006 and sediment ?PCB, ?DDT concentrations and fine sediment grain size in 2005. While fish at one SOP wetland had hepatic EROD activity elevated above the estimated basal level for this species, these were at the lower end of the range measured in urban impacted, non-remediated wetlands. EROD activity was positively correlated with both the sediment ?PCB load and aqueous TCDDeq. Increased catchment size was correlated with increased EROD activity suggesting an even spread of POPs throughout the residential areas of the Sydney metropolitan area. The concentration of bioactive POPs in the wetlands of SOP is therefore low relative to urban reference sites demonstrating the ongoing success of the remediation program. Crown Copyri...
Patra, R.W., Chapman, J.C., Lim, R.P., Gehrke, P.C. & Sunderam, R.M. 2009, 'EFFECTS OF TEMPERATURE ON VENTILATORY BEHAVIOR OF FISH EXPOSED TO SUBLETHAL CONCENTRATIONS OF ENDOSULFAN AND CHLORPYRIFOS', ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, vol. 28, no. 10, pp. 2182-2190.
Ngo, H.H., Chuang, H., Guo, W.S., Ho, D.P., Pham, T.T.N., Johnston, A., Lim, R. & Listowski, A. 2009, 'Resident's strategy survey on a new end use of recycled water in Australia', Desalination and Water Treatment, vol. 11, no. 1-3, pp. 93-97.
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The concept of using recycled water for washing machine was introduced as a new end use. As there is a noticeable lack social research in understanding the general public perceptions of this application, the resident's strategy survey was carried out at some selective suburbs in Sydney with demographically based significant differences of general, gender, age, education, and property style and ownership. The survey indicates that the majority in the community considers the use of recycled water for washing machine is indispensable in view of continuing drought and the associated water shortages. Given safety assurance and demonstration, recycled water for washing machine has a considerable proportion within the responses. The general level of knowledge in community clearly understand that recycled water is more environmentally friendly option, whereas from cleanness and public health point of view, higher quality water is required to be reused in washing machine. Moreover, the residents reckon to have a small unit for pre-treatment (point of use) before recycled water entering washing machines might assure the quality and safety. The survey also shows the major concerns for a resident to use recycled water for washing machine are public health, water cleanness and washing machine durability. &copy; 2009 Desalination Publications.
Pablo, F., Krassoi, F.R., Jones, P.R.F., Colville, A.E., Hose, G.C. & Lim, R.P. 2008, 'Comparison of the fate and toxicity of chlorpyrifos-Laboratory versus a coastal mesocosm system', Ecotoxicology and Environmental Safety, vol. 71, no. 1, pp. 219-229.
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The widespread use of chlorpyrifos for pest control in urban and rural environments poses a risk of contamination to aquatic environments via runoff, spray drift or spillage. The aim of this study was to assess the fate of chlorpyrifos and its toxicity to common freshwater invertebrates in the laboratory and in stream mesocosms. Chlorpyrifos was rapidly lost from the test systems but the rates of loss varied considerably, such that losses in the mesocosms could not be reliably predicted from the static laboratory studies. This was likely due to the mass transport of chlorpyrifos from the mesocosm via stream flow. Chlorpyrifos was acutely toxic to all invertebrates tested with the cladoceran species (laboratory 48 h LC50 values 0.07-0.10 ?g L-1) being most sensitive. Despite the differences in the dynamics of chlorpyrifos in the laboratory and mesocosm systems, the sensitivities of the mayfly Atalophlebia australis and the cladoceran Simocephalus vetulus were similar in the 2 systems. &copy; 2007 Elsevier Inc. All rights reserved.
Rawson, C.A., Lim, R.P. & Warne, M.S.J. 2008, 'Skeletal morphology and maturation of male Gambusia holbrooki exposed to sewage treatment plant effluent', Ecotoxicology and Environmental Safety, vol. 70, no. 3, pp. 453-461.
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Sewage effluent has been identified as a major source of endocrine disrupting chemicals (EDCs) in the aquatic environment. The modified hemal spines (modified skeletal structures important in reproduction) of mosquitofish, Gambusia spp. have been shown to be under androgenic control and to be affected by exposure to estrogen. The current study aimed to investigate the effects of two sewage treatment plants (STPs) in Sydney, Australia on the morphology of hemal spines in populations of Gambusia holbrooki and on the ability of the fish to reach sexual maturity. The effluent from the two STPs had different effects on the hemal spines of males. At St. Marys differences in hemal spine morphology between fish upstream and downstream of the STP were not attributable to effluent from the STP. At Quakers Hill, results suggest that the effluent is generally estrogenic to G. holbrooki. There was a decrease in the proportion of males that were morphologically mature downstream of both STPs indicating potential population level effects that were associated with the presence of the STPs. &copy; 2008 Elsevier Inc. All rights reserved.
Colville, A.E., Jones, P.M., Pablo, F., Krassoi, R., Hose, G.C. & Lim, R.P. 2008, 'Effects of chlorpyrifos on macroinvertebrate communities in coastal stream mesocosms', Ecotoxicology, vol. 17, no. 3, pp. 173-180.
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This study measured the effects of a single pulse of chlorpyrifos at nominal concentrations of 1 and 10 mu g/l on the macroinvertebrate community structure of a coastal stream mesocosm system. Analysis of data using Principal Response Curves (PRC) and Monte Carlo tests showed significant changes in the treated stream mesocosms relative to that of the controls. These changes in the macroinvertebrate assemblages occurred within 6 h, and persisted for at least 124 days after dosing. Significant community-level effects were detected at the lowest concentration on days 2 and 16 post-dosing, giving a no-observed effect concentration (NOECcommunity) of 1.2 mu g/l (measured). The mayflies Atalophlebia sp. and Koorrnonga sp., Chironomidae and Acarina were all sensitive to chlorpyrifos and decreased in abundance in treated mesocosms after dosing. The fauna of these coastal stream mesocosms showed similar sensitivity to chlorpyrifos with that of other reported studies, but there was no evidence of recovery after 124 days.
Thomas, C.R., Hose, G.C., Warne, M.S.J. & Lim, R.P. 2008, 'Effects of river water and salinity on the toxicity of deltamethrin to freshwater shrimp, cladoceran, and fish', Archives of Environmental Contamination and Toxicology, vol. 55, no. 4, pp. 610-618.
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Deltamethrin is a pyrethroid insecticide used extensively to control invertebrate pests on cotton and other crops. It is acutely toxic to nontarget aquatic organisms, but existing toxicity data are mostly from toxicity tests using purified laboratory water that differs greatly from the turbid, high-conductivity rivers in the cotton-growing regions of Australia. The aim of this study was to determine whether the water quality variables conductivity, suspended particles, and dissolved organic matter alter the toxicity of deltamethrin to freshwater crustaceans and a fish. We tested three Australian native species: a cladoceran (Ceriodaphnia cf. dubia), a freshwater shrimp (Paratya australiensis), and larvae of the eastern rainbow fish (Melanotaenia duboulayi). Conductivity of the test solutions ranged from 200 to 750 ?S/cm, but such changes did not modify the toxicity of deltamethrin to any of the test species. However, the toxicity of deltamethrin to C. cf. dubia and P. australiensis in river water was significantly decreased (1.8-fold to 6.3-fold reduction) compared to that in laboratory water. Variability in the toxicity data limited our ability to detect differences between laboratory and river water for M. duboulayi. Despite reductions in toxicity in natural waters, deltamethrin remained highly toxic [all L(E)C50 values <0.26 ?g/L] to all organisms tested; thus, further investigation of the hazard of deltamethrin is warranted. &copy; 2008 Springer Science+Business Media, LLC.
Yin, L.P., Warne, M.S.J. & Lim, R.P. 2008, 'Assessing the biological relevance of exposing freshwater organisms to atrazine and molinate in environmentally realistic exposure test systems', Environmental Toxicology and Chemistry, vol. 27, no. 2, pp. 420-424.
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Assessing the toxicity of chemicals in treated laboratory water may not accurately represent the toxicity of chemicals in natural aquatic systems. In natural water, dissolved organic matter, suspended particulate matter, and sediment play key roles in the sorption of contaminants from the water. Our previously published series of papers illustrated that the presence of sediment in aquatic toxicity testing systems significantly (p < 0.05) reduced the bioavailability of the herbicides atrazine and molinate to five Australian freshwater organisms. It is not clear whether the reduced bioavailability means that the trigger values (TVs) in the current Australian and New Zealand water quality guidelines, which are calculated using toxicity data from water-only toxicity tests, provide appropriate environmental protection. Several new sets of TVs were derived in the present study and were compared to each other and to the current Australian and New Zealand TVs for atrazine and molinate. The current Australian and New Zealand TVs for atrazine and molinate provided appropriate protection to Australian freshwater species. Australian freshwater species have a sensitivity distribution similar to those of overseas species to atrazine and molinate. &copy; 2008 SETAC.
Patra, R.W., Chapman, J.C., Lim, R.P. & Gehrke, P.C. 2007, 'The effects of three organic chemicals on the upper thermal tolerances of four freshwater fishes', Environmental Toxicology and Chemistry, vol. 26, no. 7, pp. 1454-1459.
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The upper temperature tolerance limits of four freshwater fish species, silver perch Bidyanus bidyanus, eastern rainbowfish Melanotaenia duboulayi, western carp gudgeon Hypseleotris klunzingeri, and rainbow trout Oncorhynchus mykiss, were determined using the critical thermal maximum (CTMaximum) method. The CTMaximum tests were carried out with unexposed fish and fish exposed to sublethal concentrations of endosulfan, chlorpyrifos, and phenol to determine whether or not the CTMaximum was affected. The CTMaximum temperature of B. bidyanus decreased by 2.8, 3.8, and 0.3&deg;C on exposure to endosulfan, chlorpyrifos, and phenol, respectively. Similarly, in M. duboulayi, the CTMaximum was decreased by 4.1, 2.5, and 0&deg;C, while in H. klunzingeri it decreased by 3.1, 4.3, and 0.1&deg;C, respectively, and in O. mykiss by 4.8, 5.9, and 0.7&deg;C, respectively. Exposure to sublethal test concentrations of endosulfan and chlorpyrifos caused significant (p ? 0.0001) reductions in CTMaximum values for all fish species compared to that of unexposed fish. However, exposure to phenol did not cause any significant (p ? 0.05) change of CTMaximum temperatures. &copy; 2007 SETAC.
Rawson, C.A., Lim, R.P., Warne, M.S. & Doyle, C.J. 2006, 'The effect of 17 beta-estradiol on the development of modified hemal spines in early-life stage Gambusia holbrooki', ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY, vol. 51, no. 2, pp. 253-262.
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Game, C., Gagnon, M., Webb, D. & Lim, R.P. 2006, 'Endocrine disruption in make mosquitofish (Gambusia holbrooki) inhabiting wetlands in Westerna Australia', Ecotoxicology, vol. 15, no. 8, pp. 665-672.
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The use of gonopodial indices as potential indicators of endocrine disruption in the mosquitofish Gambusia holbrooki inhabiting south west Australian wetlands was investigated. A minimum of 50 mature makes was collected from each of five water-bodies in the Swan Coastal Plain, Western Australia, in order to measure morphological features related to reproduction. A set of morphological measurements were used to derive the following indices: gonopodium length/ standard body length, pre-anal length/standard body length, the index of elongation and the percentage of male fish with hooks on the distal end of the gonopodium. Indices of male mosquitofish collected from Jack Finney Lake, located in the Curtin University campus, suggest the presence of endocrine disrupting chemicals (EDCs) in this eater-body, while those from Lake Kulinup suggest this is a site of concern. Indices of male fish from the Wagerup wetland, Lake Monger and Loch McNess indicate that fish inhabiting these wetlands are not affected by EDCs. This preliminary study suggests that EDCs may be present ina number of wetlands of the Swan Coastal Plain. Further study using EDC specific markers such as vitellogenin induction in male mosquitofish is required to confirm whether EDCs are present in these water-bodies.
Rose, R.M., Carruthers, A., Stauber, J.L., Lim, R.P. & Blockwell, S. 2006, 'Development of an acute toxicity test with the marine copepod acartia sinjiensis', Australasian Journal of Ecotoxicology, vol. 12, pp. 67-75.
Few toxicity test protocols with tropical marine species are currently available in Australasia. In this study, an acute 48h immobilisation toxicity test was developed with an native marine copepod Acartia sinjiensis. This species is widley distributed in tropical and sub-tropical brackish waters in Australia and is an important component of marine food webs. A comparison of its sensitivity to other species shwoed that this copepod was amongst the most sensitive Australian species to copper
Phyu, Y.L., Warne, M.S.J. & Lim, R.P. 2006, 'Toxicity and bioavailability of atrazine and molinate to the freshwater fish (Melanotenia fluviatilis) under laboratory and simulated field conditions', Science of the Total Environment, vol. 356, no. 1-3, pp. 86-99.
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Acute (96 h) semi-static toxicity tests were conducted by exposing the freshwater fish, Melanotenia fluviatilis, to atrazine and molinate in laboratory and river water both with and without sediment. The 96-h EC50 (imbalance) values of atrazine to M. fluviatilis ranged from 5.6 to 10.4 mg L-1 while the corresponding values for molinate ranged from 7.9 to 14.8 mg L -1, respectively. Atrazine was classed as having moderate toxicity while molinate had low to moderate toxicity to M. fluviatilis. Neither the presence of river water nor sediment significantly (P < 0.05) reduced the bioavailability of either herbicide to M. fluviatilis. A series of other studies by the authors have found that sediment significantly (P < 0.05) reduced the bioavailability of these two chemicals to a variety of organisms. Reasons for sediment having no effect for this species were examined. This lack of effect by sediment is most likely due to the relative rates of absorption into the fish and adsorption onto the sediment. However, contributions to this outcome by resuspended sediment, contaminated food and a combined effect of the herbicides and sediment could not be excluded. &copy; 2005 Elsevier B.V. All rights reserved.
Phyu, Y.L., Warne, M.S.J. & Lim, R.P. 2005, 'The toxicity and bioavailability of atrazine and molinate to Chironomus tepperi larvae in laboratory and river water in the presence and absence of sediment', Chemosphere, vol. 58, no. 9, pp. 1231-1239.
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Acute (10 day) semi-static toxicity tests in which the midge, Chironomus tepperi, were exposed to atrazine and molinate were conducted in laboratory water and in river water, in the absence and presence of sediment. The bioavailability measured as median lethal concentrations (LC50) and 95% fiducial limits (FLs) of atrazine to C. tepperi in laboratory water in the absence and presence of sediment were 16.6 (14.3-19.4) and 21.0 (18.2-24.1) mg l-1, respectively while the corresponding values in river water were 16.7 (14.7-19.0) and 22.7 (20.3-25.4) mg l-1, respectively. For molinate, the LC50 and FL values in laboratory water in the absence and presence of sediment were 8.8 (6.8-11.4) and 14.3 (12.4-16.4) mg l -1, respectively and the corresponding values in river water were 9.3 (7.6-11.3) and 14.5 (12.4-16.9) mg l-1, respectively. Atrazine has low toxicity (LC50 > 10 mg l-1) while molinate has moderate toxicity (1 mg l-1 < LC50 < 10 mg l -1) to C. tepperi. River water did not significantly (P > 0.05) reduce the bioavailability of either chemical to C. tepperi. However, the presence of sediment did significantly (P < 0.05) reduce the bioavailability of both atrazine and molinate to C. tepperi. &copy; 2004 Elsevier Ltd. All rights reserved.
Hose, G.C., Jones, P. & Lim, R.P. 2005, 'Hyporheic macroinvertebrates in riffle and pool areas of temporary streams in south eastern Australia', Hydrobiologia, vol. 532, no. 1, pp. 81-90.
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The hyporheic zone is an important refuge for invertebrates as surface water recedes in temporary streams. In this study, the structure and functional organisation of hyporheic macroinvertebrate assemblages in pool and dry riffle bed habitats of two episodic streams were compared over summer and winter. Multivariate analyses revealed macroinvertebrate assemblages differed significantly between streams, habitats and seasons. While some seasonal differences were expected, the differences between streams were not, given the similarity and proximity of the catchments, and were due to shifts in the abundance of common taxa. Distinct differences between riffle and pool habitats were evident in both the taxonomic and functional feeding group composition of the assemblages. In particular, riffle habitats contained greater numbers of taxa and individuals and a greater proportion of filter-feeding animals compared to pool habitats. Summer samples also had greater numbers of taxa and individuals and greater proportions of collector-scrapers than winter samples. The relative abundance of functional groups was similar between streams in summer but was more variable in winter. Patterns observed in the taxonomic and functional feeding group structure of the macroinvertebrate assemblages were more characteristic of perennial than episodic streams, despite the absence of regular surface flows. This could be attributed to the relatively constant hyporheic flow in these streams. We suggest that classifications of stream flow should consider hyporheic discharge (not just surface flow) as this clearly influences the stream biota. &copy; Springer 2005.
Hogan, A.C., Stauber, J.L., Pablo, F., Adams, M.S. & Lim, R.P. 2005, 'The development of marine toxicity identification evaluation (TIE) procedures using the unicellular alga Nitzschia closterium', Archives of Environmental Contamination and Toxicology, vol. 48, no. 4, pp. 433-443.
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Unicellular algae are highly sensitive to a wide range of toxicants and have been used extensively in ecotoxicological testing. This, along with their ability to grow in very small test volumes over short test durations, make them ideal test organisms for use in Toxicity Identification Evaluations (TIEs). Despite this, microalgae have not previously been used in marine TIE studies. In this study, the marine diatom Nitzschia closterium was shown to be a highly suitable test organism after modification of the standard test protocol to reduce test volumes to 6 mL and test duration to 48 h. The alga was tolerant to the chemicals used in phase I of the standard USEPA TIE protocol, and physical TIE manipulations had no effect on algal growth. The cation exchange procedure, however, inhibited algal growth, while the anion exchange procedure stimulated growth, making these two procedures unsuitable for use with this species. Of the buffers trialed for the graduated pH procedure, 0.01 M PIPES buffer was found to be suitable for buffering at pH 7 because it maintained the required pH over the duration of the test and did not affect the growth or sensitivity of the algae to one reference toxicant (copper). A trial TIE on a secondary-treated sewage effluent for discharge into coastal waters showed that the developed protocols could successfully be used to identify ammonia as the major toxicant in the effluent. &copy; 2005 Springer Science+Business Media, Inc.
Yin, L.P., Warne, M.S.J. & Lim, R.P. 2005, 'Effect of river water, sediment and time on the toxicity and bioavailability of molinate to the marine bacterium Vibrio fischeri (Microtox)', Water Research, vol. 39, no. 12, pp. 2738-2746.
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The toxicity and bioavailability of molinate to Vibrio fischeri (Microtox&reg;) were determined in both laboratory and river water in the absence and presence of sediment after 0, 24, 48, 72 and 96-h exposure. The bioavailability of molinate, expressed as 5 min EC50s (bioluminescence) and their fiducial limits calculated using initial measured concentrations, to V. fischeri in laboratory water in the absence and presence of sediment ranged from 1.8 (1.7-2.1) to 3.6 (3.5-3.7) mg L-1 and 1.3 (1.2-1.4) to 4.2 (3.5-4.5) mg L-1, respectively. The corresponding values in river water and river water plus sediment were 1.7 (1.6-1.8) to 3.8 (3.6-4.1) and 1.3 (1.3-1.4) to 4.6 (4.2-4.9) mg L-1, respectively. River water did not significantly (P>0.05) reduce the bioavailability of molinate to V. fischeri compared to that of laboratory water. However, the presence of sediment significantly (P<0.05) reduced the bioavailability of molinate to V. fischeri in both waters. The exposure time also significantly (P<0.05) reduced the bioavailability of molinate to V. fischeri in both waters in the presence and absence of sediment. The type of water did not significantly (P>0.05) affect the loss of molinate during the 96-h exposure period. However, the presence of sediment significantly (P<0.01) increased the loss of molinate from the test solutions, probably by binding to the sediment particles. Exposure period and concentration levels significantly (P<0.05) affected the loss of the herbicides over the 96 h. &copy; 2005 Elsevier Ltd. All rights reserved.
Doyle, C.J. & Lim, R.P. 2005, 'Sexual behavior and impregnation success of adult male mosquitofish following exposure to 17?-estradiol', Ecotoxicology and Environmental Safety, vol. 61, no. 3, pp. 392-397.
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The effects of 17?-estradiol (E2) on the sexual activity of adult male mosquitofish (Gambusia holbrooki) were assessed. Sexually mature males were exposed to nominal concentrations of 20, 100, and 500 ng/L of E 2 and a solvent control (0.00001% ethanol v/v) for 84 days under continuous flow conditions. Following exposure, males exposed to E2 at concentrations of 20 ng/L and above displayed a lower level of sexual activity, measured as the number of approaches and copulation attempts made toward nonexposed females, than the control males. In addition, E 2-exposed males were less capable of impregnating females than the control males. Exposure to E2 had no significant effect on spermatozeugmata production or the secondary sexual characteristics, indicating that the reduced impregnation efficiency of the E2-exposed males was most likely due to the decline in sexual activity. &copy; 2004 Elsevier Inc. All rights reserved.
Phyu, Y.L., Warne, M.S.J. & Lim, R.P. 2005, 'Toxicity and bioavailability of atrazine and molinate to the freshwater shrimp (Paratya australiensis) under laboratory and simulated field conditions', Ecotoxicology and Environmental Safety, vol. 60, no. 2, pp. 113-122.
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Acute (96-h) semistatic toxicity tests were conducted by exposing the freshwater shrimp, Paratya australiensis, to atrazine and molinate in laboratory water and in river water both with and without sediment. The median lethal concentrations (LC50) and 95% fiducial limits of atrazine for P. australiensis in laboratory water in the absence and presence of sediment were 9.9 (8.6-11.5) and 6.8 (5.4-8.5) mg/L, respectively, while the corresponding values in river water were 9.8 (8.5-11.2) and 6.5 (5.4-7.8) mg/L, respectively. For molinate, the LC50 values in laboratory water in the absence and presence of sediment were 9.2 (7.0-12.1) and 9.0 (6.8-12.0) mg/L, respectively and the corresponding values in river water were 8.7 (6.4-11.8) and 8.2 (6.6-10.2) mg/L, respectively. Neither the river water nor the presence of sediment significantly (P<0.05) reduced the bioavailability of either chemical to P. australiensis. This was unexpected, as studies with other aquatic organisms have shown that sediment significantly reduced the bioavailability of these chemicals. &copy; 2004 Elsevier Inc. All rights reserved.
Franklin, N.M., Stauber, J.L. & Lim, R.P. 2004, 'Development of multispecies algal bioassays using flow cytometry', Environmental Toxicology and Chemistry, vol. 23, no. 6, pp. 1452-1462.
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Multispecies algal bioassays, suitable for assessing copper toxicity, were developed with three marine (Micromonas pusilla, Phaeodactylum tricornutum, and Heterocapsa niei) and three freshwater (Microcystis aeruginosa, Pseudokirchneriella subcapitata, and Trachelomonas sp.) microalgae. Flow cytometry was used to separate and count algal signals based on pigment fluorescence and cell size. Species were mixed together on the basis of equivalent surface areas to avoid the confounding effect on toxicity of increased biomass for metal binding. Under control conditions (no added copper), M. pusilla growth was inhibited in the presence of the other marine microalgae compared to single-species tests, while the opposite was true (i.e., growth stimulation) for M. aeruginosa and P. subcapitata in freshwater mixtures. Competition for nutrients, including CO2, and algal exudate production may account for these effects. Interactions between microalgal species also had a significant effect on copper toxicity to some species. In freshwater multispecies bioassays, the toxicity of copper to Trachelomonas sp. was greater in the presence of other species, with copper concentrations required to inhibit growth (cell division) rate by 50% (72-h [IC50]) decreasing from 9.8 to 2.8 ?g Cu/L in single- and multispecies bioassays, respectively. In contrast, in marine multispecies bioassays, copper toxicity to the marine diatom P. tricornutum was reduced compared to single-species bioassays, with an increase in the 72-h IC50 value from 13 to 24 ?g Cu/L. This reduction in copper toxicity was not explained by differences in the copper complexing capacity in solution (as a result of exudate production) because labile copper, measured by anodic stripping voltammetry, was similar for P. tricornutum alone and in the mixture. These results demonstrate that single-species bioassays may over- or underestimate metal toxicity in natural waters.
Phyu, Y.L., Warne, M.S.J. & Lim, R.P. 2004, 'Toxicity of Atrazine and Molinate to the Cladoceran Daphnia carinata and the Effect of River Water and Bottom Sediment on Their Bioavailability', Archives of Environmental Contamination and Toxicology, vol. 46, no. 3, pp. 308-315.
Atrazine and molinate are widely used herbicides and concern has been raised about their potential deleterious impacts on aquatic ecosystems. Although there have been some studies on the toxicity of herbicides to aquatic organisms using laboratory or natural water, information on the effect of sediments, suspended particulates, and dissolved organic matter on their bioavailability is quite limited. This study aims to provide toxicity data that considers these factors and the effect that these factors have on bioavailability. In this study, the toxicity of the test chemicals was calculated following the Organisation for Economic Co-operation and Development (OECD) methods, whereas change in bioavailability was measured using EC 50 values based on measured initial concentrations of the test chemicals. The acute (48-h) static toxicity of atrazine and molinate to the freshwater cladoceran Daphnia carinata was determined in cladoceran water and river water in the absence and presence of sediment. The 48-h EC50 (immobilization) values of atrazine to D. carinata ranged from 22.4 to 26.7 mg/L, while the corresponding values for molinate ranged from 18.3 to 33.6 mg/L, respectively. Both chemicals were classed as having low acute toxicity to D. carinata. The presence of dissolved organic matter and suspended particles in river water did not significantly (p > 0.05) reduce the bioavailability (measured as toxicity) of atrazine to D. carinata compared to that tested in cladoceran water. The presence of sediment, however, significantly (p < 0.05) reduced the bioavailability (48-h EC50) of atrazine in cladoceran water, from 24.6 to 30.7 mg/L, and in river water, from 22.4 to 31.0 mg/L. Similarly, the presence of sediment in cladoceran water, significantly (p < 0.05) reduced the bioavailability (48-h EC50) of molinate, from 26.6 to 46.4 mg/L, and in river water, from 22.5 to 45.6 mg/L.
Westbury, A., Warne, M.S. & Lim, R.P. 2004, 'Toxicity of, and development of predictive models for, substituted phenols to Ceridaphnia cf. dubia and Vibrio fischeri', Australasian Journal for Ecotoxicology, vol. 10, no. 1, pp. 33-42.
Twelve substituted phenols that have a polar narcotic mode of action had their acute toxicity to the freshwater cladoceran Ceriodaphnia cf. dubia and the marine bacterium Vibrio fischeri determined. The 48-h EC50 (immobilisation) values of the chemicals to C. cf. dubia ranged from 6.13 to 183 &Ecirc;mol/L while the 30-min EC50 (luminescence) values of the chemicals to V. fischeri ranged from 1.39 to 1031 &Ecirc;mol/L. Seventy-five percent of the chemicals were classed as having moderate toxicity of to C. cf. dubia while 25 percent had below toxicity?f. For V. fischeri the percentage of chemicals classified as having high moderate and below toxicity was approximately 17%, 33% and 50% respectively. Quantitative activity-activity relationships (QAARs) that could predict the toxicity of chemicals with a polar narcotic mode of action to C. cf. dubia were developed by regressing the toxicity data for polar narcotic chemicals to C. cf. dubia with that of eight non-Australasian species. Those QAARs based on the toxicity data for Tetrahymena pyriformis, Chlorella vulgaris, Poecilia reticulata and Daphnia magna were of high quality (r2 . 0.9). Only the QAARs for T. pyriformis, C. vulgaris and D. magna had sufficient data to test their validity. This revealed that the absolute percentage difference between experimentally derived EC50 values and those predicted by these QAARs were between 13 and 120%. These QAARs provide an easy, cost-effective means of estimating toxicity values for polar narcotic chemicals to C. cf. dubia.
Rose, R.M., Warne, M.S.J. & Lim, R.P. 2004, 'Sensitivity of offspring to chronic 3,4-dichloroaniline exposure varies with maternal exposure', Ecotoxicology and Environmental Safety, vol. 58, no. 3, pp. 405-412.
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Many anthropogenic pollutants are present in aquatic systems for extended periods of time. Populations in the field may be exposed to toxicants for several generations, which may affect their sensitivity to toxicants. Ceriodaphnia cf. dubia mass cultures were maintained for four generations in various concentrations of 3,4-dichoroaniline (0, 2.5, 5, 10, and 15?g/L) and were reestablished every generation using fourth-brood neonates. Each generation, chronic toxicity tests were initiated using fourth-brood neonates from each mass culture treatment. Significantly (P<0.05) reduced sensitivity to 3,4-dichloroaniline compared to control animals was shown by F1 offspring from mothers exposed to 15?g/L, F2 offspring from mothers exposed to 5, 10, and 15?g/L, F3 offspring from mothers exposed to 10 and 15?g/L, and F4 offspring from mothers exposed to all 3,4-dichloroaniline treatments (2.5, 5, 10, and 15?g/L). Possible explanations for the development of tolerance, and the possible implications of tolerance, are discussed. &copy; 2003 Elsevier Inc. All rights reserved.
Doyle, C.J., Pablo, F., Lim, R.P. & Hyne, R.V. 2003, 'Assessment of metal toxicity in sediment pore water from Lake Macquarie, Australia', Archives of Environmental Contamination and Toxicology, vol. 44, no. 3, pp. 343-350.
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Recent investigations into the level of heavy metal enrichment in the sediments of Lake Macquarie have indicated that significant contamination has occurred over the past 100 years, with elevated levels of lead, zinc, cadmium, copper, and selenium being observed in most parts of the lake. Pore water extracted from sediments showing the greatest contamination by these metals exhibited toxicity to the larval development of the sea urchin Heliocidaris tuberculata. However, an analysis of pore water metal concentrations revealed that the concentrations of these metals were too low to cause toxicity. Rather, pore water toxicity was highly correlated with manganese for the majority of sites sampled; subsequent spiking experiments confirmed manganese as a cause of toxicity. Current levels of manganese in the sediments of Lake Macquarie have arisen from natural sources and are not the result of anthropogenic activities. These results reiterate the importance of identifying the causes of toxicity in assessments of sediment contamination, particularly when testing sediment pore waters using sensitive early life stages.
Hose, G.C., Lim, R.P., Hyne, R.V. & Pablo, F. 2003, 'Short-term exposure to aqueous endosulfan affects macroinvertebrate assemblages', Ecotoxicology and Environmental Safety, vol. 56, no. 2, pp. 282-294.
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The toxicity of the organochlorine pesticide endosulfan to macroinvertebrate assemblages was tested using a system of 24 artificial streams. In separate experiments, the effects of 12- and 48-h exposure to aqueous endosulfan were assessed. No-observed-effect concentrations (NOEC) for endosulfan on macroinvertebrate assemblages were 8.69 and 1.00?g/L for the 12- and 48-h exposure studies, respectively. In both studies, changes were driven by reduced abundances of the mayfly, Jappa kutera. Algal blooms occurred in the 48-h exposure experiment in streams that received the 6.87 or 30.70?g/L treatments. These effects occurred at concentrations that might occur as a result of episodic events such as accidental overspray or rainstorms. By establishing a causal link between endosulfan and changes to macroinvertebrate assemblages, this study adds further weight to the hypothesis that endosulfan is a major contributor to changes observed in rivers of the cotton-growing region of New South Wales, Australia during the pesticide spray season. &copy; 2003 Elsevier Science (USA). All rights reserved.
Markich, S.J., Brown, P.L., Jeffree, R.A. & Lim, R.P. 2003, 'The Effects of pH and Dissolved Organic Carbon on the Toxicity of Cadmium and Copper to a Freshwater Bivalve: Further Support for the Extended Free Ion Activity Model', Archives of Environmental Contamination and Toxicology, vol. 45, no. 4, pp. 479-491.
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The extended free ion activity model (FIAM) was developed by integrating concepts from the original FIAM into biological receptor theory, to obtain a conceptual model that more precisely quantifies the interaction of chemical species at biological receptor sites. The extended FIAM was tested by determining the acute (48 h) valve movement behavior (VMB) (measured in terms of the duration of valve opening) of the Australian freshwater bivalve, Hyridella depressa, to increasing concentrations of total Cd or Cu, in a standard synthetic water under conditions of varying pH (6.5-7.5) and/or dissolved organic carbon (as model fulvic acid (FA)) concentrations (0-11.2 mg L-1). Valve movement behavior, measured using an automated data acquisition system, was shown to be a quantifiable and rapid, real-time endpoint for assessing the toxic effects of Cd and Cu exposures. The VMB of H. depressa to Cd was independent (p > 0.05) of pH and/or model FA concentration. In contrast, the VMB of H. depressa to Cu was highly dependent (p < 0.001) on pH and/or model FA concentration; individuals were more sensitive to Cu at low pH and model FA concentrations. The VMB of H. depressa was directly proportional to the activity of the free metal ion (Cd 2+), for the linear region of the concentration-response curves. In contrast, the VMB of H. depressa was a weighted function of the activities of the free metal ion and the 1:1 metal hydroxide species (i.e. 2.02 Cu2+ + CuOH+), whereby Cu2+ had a two-fold greater binding affinity than CuOH+ at the cell membrane surface. Moreover, the results for Cd and Cu are consistent with the extended FIAM, as opposed to the original FIAM, where the result for Cu would be regarded as an exception. The extended FIAM explained 98% of the variability in VMB, whereas the original FIAM explained only 63% (i.e. an improvement of 35%). The improved predictability of organism response to Cu is relevant to advancing water quality guidelines for protecting aquatic ...
Hose, G.C., Hyne, R.V. & Lim, R.P. 2003, 'Toxicity of endosulfan to Atalophlebia spp. (ephemeroptera) in the laboratory, mesocosm, and field', ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, vol. 22, no. 12, pp. 3062-3068.
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Hose, G.C., Lim, R.P. & Hyne, R.V. 2003, 'The transport, fate and effects of endosulfan in the Australian freshwater environment', Australasian Journal of Ecotoxicology, vol. 9, pp. 101-111.
Settacharnwit, S., Buckney, R.T. & Lim, R.P. 2003, 'The nutrient status of Nong Han, a shallow tropical lake in north-eastern Thailand: spatial and temporal variations', Lakes & Reservoirs: Research and Management, vol. 8, pp. 189-200.
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Colville, A.E. & Lim, R.P. 2003, 'Microscopic structure of the mantle and palps in the freshwater mussels velesunio ambiguus and hyridella depressa (Bivalvia: Hyriidae)', Molluscan Research, vol. 23, no. 1, pp. 1-20.
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There has been increasing interest in freshwater mussels (order Unionoida) in recent years because their numbers are declining in many parts of the world and also because they have potential as monitors of pollution. Most studies have been performed on the families Unionidae and Margaritiferidae from North America and Europe, and comparatively little is known of the Hyriidae from Australasia. The present study describes the microscopic structure of tissues in the mantle and palps of two hyriid mussels, namely Velesunio ambiguus and Hyridella depressa, as viewed by light and electron microscopy. The two mussels show similarities with the unionids and margaritiferids, particularly the presence of extracellular mineralised granules. The mantle and palps of V. ambiguus and H. depressa consist of flaps of tissue bordered on the inner and outer surfaces by simple epithelia. The intervening tissue is dominated by connective tissue containing vesicular cells, muscle, nerves and blood spaces with haemocytes. Orange-yellow extracellular calcified granules are a prominent feature of the interstitial tissues. The abundance of calcified granules in the mantle of H. depressa is greater than that in V. ambiguus and there are differences in the appearance of the apical vesicles in epithelial cells. &copy; Malacological Society of Australasia 2003.
Binet, M.T., Adams, M.A., King, C.K., Stauber, J.L., Doyle, C., Lim, R.P. & Laginestra, E. 2003, 'Toxicity assessment of leachates from Homebush Bay landfills', Australasian Journal of Ecotoxicology, vol. 9, pp. 7-18.
Hammerton, K.M., Jayasinghe, N., Jeffree, R.A. & Lim, R.P. 2003, 'Experimental study of blood lead kinetics in estuarine crocodiles (Crocodylus porosus) exposed to ingested lead shot', ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY, vol. 45, no. 3, pp. 390-398.
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Rose, R.M., Warne, M.S.J. & Lim, R.P. 2003, 'Exposure to chemicals exuded by fish reduces the filtration and ingestion rates of Ceriodaphnia cf. dubia', Hydrobiologia, vol. 501, pp. 215-217.
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Gale, S.A., Smith, S.V., Lim, R.P., Jeffree, R.A. & Petocz, P. 2003, 'Insights into the mechanisms of copper tolerance of a population of black-banded rainbowfish (Melanotaenia nigrans) (Richardson) exposed to mine leachate, using Cu-64/67', AQUATIC TOXICOLOGY, vol. 62, no. 2, pp. 135-153.
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Franklin, N.M., Stauber, J.L., Apte, S.C. & Lim, R.P. 2002, 'The effect of initial cell density on the bioavailability and toxicity of copper in microalgal bioassays', Environmental Toxicology and Chemistry, vol. 21, no. N/A, pp. 742-751.
Franklin, N.M., Stauber, J.L., Lim, R.P. & Petocz, P. 2002, 'Toxicity of metal mixtures to a tropical freshwater alga (Chlorella sp.): effect of interactions between copper, cadmium and zinc on metal cell binding and uptake', Environmental Toxicology and Chemistry, vol. 21, no. N/A, pp. 2412-2422.
Hose, G.C., Lim, R.P., Hyne, R.V. & Pablo, F. 2002, 'A pulse of endosulfan-contaminated sediment affects macroinvertebrates in artificial streams', Ecotoxicology and Environmental Safety, vol. 51, no. 1, pp. 44-52.
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The toxicity of the organochlorine pesticide endosulfan to macroinvertebrate communities was tested using a system of 24 artificial streams. Macroinvertebrate communities in the streams were exposed to a range of endosulfan concentrations for a 12-h period and then monitored for 96 h. Endosulfan was prebound to fine river sediment and applied to the streams as a contaminated sediment slurry. This did not cause changes in the structure of benthic communities; however, significant changes (P<0.05) in the abundance of several macroinvertebrate taxa in drift were detected in the streams receiving the highest (6.14?g/L) dose. Increased drift may have implications for recolonization processes in lowland rivers, and, as such, pulses of contaminated sediment are likely to result in significant effects on macroinvertebrate populations and communities. This study highlights the utility of artificial stream systems for detecting sublethal effects and the need for population and community-level endpoints to be included in such studies. &copy; 2002 Elsevier Science.
Milner, R.J., Lim, R.P. & Hunter, D.M. 2002, 'Risks to the aquatic ecosystem from the application of Metarhizium anisopliae for locust control in Australia', Pest Management Science, vol. 58, no. 7, pp. 718-723.
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Laboratory tests of Metarhizium anisopliae var acridum Driver & Milner, at a dose of 1.3 106 conidia ml-1, had no adverse effects on nymphs of mayfly, Ulmerophlebia sp or 8-week-old fry of the rainbow fish, Melanotaenia duboulayi Castelnau. This dose was toxic to the cladoceran, Ceriodaphnia dubia Richards causing 100% mortality in 48h. When this test was repeated at doses of up to 6.7 103 conidia ml-1, there was only 5% mortality after 192h. Spraying of artificial water sources with a very high dose of the fungus as an aqueous spray resulted in 80-130 conidia ml-1 at 15 cm depth in the first 24h after spraying. The conidia rapidly settled out and were absent from the top 15 cm layer of water after about 50h. A similar experiment using the oil formulation as used in field control resulted in a 2- to 20-fold lower level of conidia in the water. Finally, sampling actual water sources in spray areas revealed a very low level of contamination of the water, with a maximum mean level of 29 conidia ml-1 in the first 24h after treatment. Thus the level of conidia likely to enter water during control campaigns is a small fraction of that required to kill cladocerans, the only sensitive non-target organism tested. It is concluded that the biopesticide is very unlikely to pose any hazard to aquatic organisms. &copy; 2002 Society of Chemical Industry.
Rose, R.M., Warne, M.S.J. & Lim, R.P. 2002, 'Food concentration affects the life history response of Ceriodaphnia cf. dubia to chemicals with different mechanisms of action', Ecotoxicology and Environmental Safety, vol. 51, no. 2, pp. 106-114.
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The effect of three chemicals with different mechanisms of action (3,4-dichloroaniline, fenoxycarb, and chlorpyrifos) on the life history response of the cladoceran Ceriodaphnia cf. dubia was examined under both limited (3 - 10 4 cells/mL) and abundant (15 - 10 4 cells/mL) food conditions. Toxicity tests were conducted at both food concentrations simultaneously for each chemical, and cladocerans were examined daily from less than 24h old until their death. A range of life history parameters were calculated, including mean brood sizes, survival, net reproductive rate, and population growth rate. The toxicity of 3,4-dichloroaniline was not significantly affected by food concentration. However, limited food significantly decreased the toxicity of fenoxycarb, and significantly increased the toxicity of chlorpyrifos. The effect of food concentration on toxicity appears to depend on the mechanism by which the chemical exerts its toxicity and on food-chemical interactions. Possible mechanisms for the different effects of food concentration on toxicity are discussed. &copy; 2002 Elsevier Science (USA).
Rose, R.M., Warne, M.S.J. & Lim, R.P. 2002, 'Some life history responses of the cladoceran Ceriodaphnia cf. dubia to variations in population density at two different food concentrations', Hydrobiologia, vol. 481, pp. 157-164.
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The combined effects of food concentration and population density on some life history characteristics of the small-bodied cladoceran Ceriodaphnia cf. dubia were studied by examining animals maintained at densities of 100-3000 individuals 1-1 for 8 days that had been fed either abundant (30 104 algal cells ml-1 ind-1) or limited (5 104 algal cells ml-1 ind-1) food. The amount of food provided significantly (p<0.05) affected the density at which the cladocerans produced fewer neonates. Cladocerans maintained at 1000 ind 1-1 produced significantly (p<0.05) fewer neonates than those at 100 or 200 ind 1-1 when fed abundant food, while cladocerans fed limited food showed a statistically significant (p<0.05) reduction in fecundity at 500 ind 1-1 compared to those at 100 or 200 ind 1-1. There was a general trend towards decreased age at sexual maturity with increased cladoceran density, and a significant (p<0.05) decrease in the age at sexual maturity for cladocerans maintained at 3000 ind 1-1 was observed in some experiments. Sexual reproduction, as indicated by the presence of resting eggs, was observed in animals maintained at 2000 and 3000 ind 1-1 and fed limited food. This indicated that, for the range of densities and food concentrations tested, a combination of crowding and limited food was required to induce sexual reproduction. Increasing the food concentration while maintaining a constant cladoceran density lead to significantly (p<0.05) increased reproduction, and no significant (p>0.05) effect on the age at sexual maturity. This indicated that the effects observed in crowded animals were not the result of negative effects due to the increased food concentrations, but were an adaptive response to crowding.
Doyle, C. & Lim, R.P. 2002, 'The effect of 17 beta-estradiol on the gonopodial development and sexual activity of Gambusia holbrooki', Environmental Toxicology and Chemistry, vol. 21, no. N/A, pp. 2719-2724.
Doyle, C.J. & Lim, R.P. 2002, 'The effect of 17?-estradiol on the gonopodial development and sexual activity of Gambusia holbrooki', Environmental Toxicology and Chemistry, vol. 21, no. 12, pp. 2719-2724.
Many chemicals have recently been demonstrated to possess estrogenic activity and may potentially interfere with normal sexual development. In the present study, we quantified the effects of waterborne exposure to 17?-estradiol on the gonopodial development and sexual activity of male eastern mosquitofish (Gambusia holbrooki). Juvenile males were exposed during the period of sexual maturation to nominal concentrations of 20, 100, and 500 ng/L of 17?-estradiol and a solvent control (0.00003% w/v ethanol) for 84 d under continuous-flow conditions. Following exposure, significant differences were found among the test treatments with respect to gonopodial length and degree of gonopodial elongation of the fish. Sexual activity, measured as the number of approaches and copulatory attempts made by the exposed males to nonexposed females, also significantly decreased with increasing concentrations of 17?-estradiol. Because the degree of gonopodial maturation and frequency of sexual activity are important characteristics for the reproductive success of male mosquitofish, it is suggested that these traits provide sensitive and ecologically relevant endpoints for assessing estrogenic activity under both laboratoryand field-exposure conditions.
Franklin, N.M., Stauber, J.L. & Lim, R.P. 2001, 'Development of flow cytometry-based algal bioassays for assessing toxicity of copper in natural waters', ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, vol. 20, no. 1, pp. 160-170.
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Rose, R.M., Warne, M.S.J. & Lim, R.P. 2001, 'Factors associated with fish modify life history traits of the cladoceran Ceriodaphnia cf. dubia', Journal of Plankton Research, vol. 23, no. 1, pp. 11-17.
This study examined the effect of water that previously contained fish on several life history traits of the small-bodied cladoceran Ceriodaphnia cf. dubia. Four fish density treatments were tested (i.e. 16.7, 5.9, 2 and 0.9 l fish-1). A significant (P < 0.05) increase in the mean generation length occurred at a fish density of 16.7 l fish-1. Fish densities of at least 5.9 l fish-1 had a significant (P < 0.05) positive effect on mean brood sizes, population growth rate and net reproductive rate. Increased fish density appeared to increase the length of time during which the cladocerans reproduced significantly (P < 0.05). None of the tested fish densities affected (P > 0.05) cladoceran survival. The observed effects are ascribed to the presence of unidentified substances in the water that previously contained fish. These substances are thought to be 'fish kairomones'. While life history changes occur in the laboratory, it remains unclear whether similar changes would occur in the field.
Leonard, A.W., Hyne, R.V., Lim, R.P., Leigh, K.A., Le, J. & Beckett, R. 2001, 'Fate and toxicity of endosulfan in Namoi River water and bottom sediment', JOURNAL OF ENVIRONMENTAL QUALITY, vol. 30, no. 3, pp. 750-759.
Franklin, N.M., Adams, M.S., Stauber, J.L. & Lim, R.P. 2001, 'Development of an improved rapid enzyme inhibition bioassay with marine and freshwater microalgae using flow cytometry', Archives of Environmental Contamination and Toxicology, vol. 40, no. 4, pp. 469-480.
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A rapid toxicity test based on inhibition of esterase activity in marine and freshwater microalgae (Selenastrum capricornutum, Chlorella sp., Dunaliella tertiolecta, Phaeodactylum tricornutum, Tetraselmis sp., Entomoneis cf. punctulata, Nitzschia cf. paleacea) was developed using flow cytometry. Uptake of fluorescein diacetate (FDA) was optimized for each species by varying the substrate concentration, incubation time, and media pH. Propidium iodide (PI) was utilized to assess membrane integrity. The optimized FDA/PI staining procedure was then used to assess the toxicity of copper in short-term exposures (1-24 h). Esterase activity was a sensitive indicator of copper toxicity in S. capricornutum and E. cf. punctulata. As copper concentrations increased, esterase activity decreased in a concentration-dependent manner. The 3- and 24-h EC50 values (based on mean activity states) were 112 ?g Cu L-1 (95% confidence limits 88-143) and 51 ?g Cu L-1 (95% confidence limits 38-70) for S. capricornutum and 47 ?g Cu L-1 (95% confidence limits 43-51) and 9.1 ?g Cu L-1 (95% confidence limits 7.6-11) for E. cf. punctulata, respectively. This enzyme inhibition endpoint showed similar sensitivity to chronic growth rate inhibition in E. cf. punctulata (48-h and 72-h EC50 values of 17 and 18 ?g L-1, respectively) but was less sensitive compared to growth for S. capricornutum (48-h and 72-h EC50 values of 4.9 and 7.5 ?g L-1, respectively). For the other five species tested, inhibition of FDA fluorescence was relatively insensitive to copper, even at copper concentrations that severely inhibited cell division rate. These short-term bioassays that detect sublethal endpoints may provide a more rapid and cost-effective way of monitoring contaminant impacts in natural waters.
Rose, R.M., Warne, M.S.J. & Lim, R.P. 2001, 'The presence of chemicals exuded by fish affects the life-history response of Ceriodaphnia cf dubia to chemicals with different mechanisms of action', ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY, vol. 20, no. 12, pp. 2892-2898.
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Leonard, A.W., Hyne, R.V., Lim, R.P. & Chapman, J.C. 1999, 'Effect of endosulfan runoff from cotton fields on macroinvertebrates in the Namoi River', ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, vol. 42, no. 2, pp. 125-134.
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Rose, R.M., Warne, M.S.J. & Lim, R.P. 1998, 'Quantitative structure-activity relationships and volume fraction analysis for nonpolar narcotic chemicals to the Australian cladoceran Ceriodaphnia cf. dubia', Archives of Environmental Contamination and Toxicology, vol. 34, no. 3, pp. 248-252.
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The toxicity of eleven nonpolar narcotic chemicals to the cladoceran Ceriodaphnia cf. dubia was determined. C. cf. dubia was found to be approximately four times more sensitive to these narcotic chemicals than Daphnia magna tested under virtually identical conditions. The toxicity data were also used to develop and validate quantitative structure-activity relationships (QSARs) using a range of physicochemical properties of the chemicals. The three best QSARs, based on octanol-water partition coefficients and two lipid-water partition coefficients, were able to explain 98% of the variation in toxicity. The mean absolute percentage errors between the predicted and experimental EC50 values for these three QSARs were 17.3%, 20.6%, 24.6%. Neither the critical concentration (CC) nor the critical volume (CV) hypotheses validly modeled the toxicity data when octanol-water and triolein-water partition coefficients were used although the CV hypothesis was the better of the two. When a phospholipid-water partition coefficient was used the CV hypothesis was valid. The mean toxic membrane volume fraction of 0.48 x 10-2 m3/m3 derived in this study agreed with published values for nonpolar narcotics and supports the use of this property to determine the mode of action of chemicals.
Olima, C., Pablo, F. & Lim, R.P. 1997, 'Comparative tolerance of three populations of the freshwater shrimp (Paratya australiensis) to the organophosphate pesticide, chlorpyrifos', Bulletin of Environmental Contamination and Toxicology, vol. 59, no. 2, pp. 321-328.
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Pablo, F., Buckney, R.T. & Lim, R.P. 1997, 'Toxicity of cyanide, iron-cyanide complexes, and a blast-furnace effluent to the banana prawn, Penaeus monodon', Bulletin of Environmental Contamination and Toxicology, vol. 58, no. 5, pp. 822-829.
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Pablo, F., Buckney, R.T. & Lim, R.P. 1997, 'Toxicity of cyanide, iron-cyanide complexes, and a blast furnace effluent to larvae of the doughboy scallop, Chlamys asperrimus', Bulletin of Environmental Contamination and Toxicology, vol. 58, no. 1, pp. 93-100.