Environmental Management
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/3753
Browse
6 results
Search Results
Item Sensitivity of freshwater organisms to cadmium and copper at tropical temperature exposures: Derivation of tropical freshwater ecotoxicity thresholds using species sensitivity distribution analysis(Ecotoxicology and Environmental Safety, 2021, 2021) Arambawatta Lekamge, S. H.; Pathiratne, A.; Rathnayake, I.V.N.Tropical freshwater ecosystems are increasingly influenced by chemical stressors including heavy metals posing threats to biodiversity. Adequate ecotoxicity data are not available for native tropical freshwater species for ...Item Assessing toxicity of two industrial zone effluents reaching Kelani River,Sri Lanka(Journal of national science foundation Sri Lanka, 2018) Hemachandral, C.K.; Pathiratne, A.Evaluation of the effcaey of waste treatment technologies of industnal waste is a major challenge for sustainable industrial development world-wide. Hence, new strategies are needed to assess interactive toxic effects of all substances present in the treated waste. This study assessed potential toxic hazards of treated effluents discharged from common wastewater treatment plants of two mclustrlal zones located in the Kelani River basin using Allium cepa (common onion) test system. The results showed that the final effluents of both industrial zones under undiluted and diluted (1 IS v/v) conditions mduced cytotoxrcity on all occasions, with evidence of significant (p < 0.05) mlto-depression In the root meristem and retardation of root growth in A. cepa. Genotoxlc hazard of the effuents was evident by frequent mcrease of nuclear and chromosomal abnormalltles, and occasional development of micronuclei in the root merlstem. Dilution of the effluents to 1 reduced the genotoxic effects generated in A. cepa roots by the final effuents_ The results revealed that waste treatment technologies m these two mdustnal zones need to be upgraded m order to ehmmate cytotoxlc and genotoxrc hazards associated with the treated effuents_ The results highlight the importance of incorporatmg practically feasible bioanalytical tools such as A. cepa root based test system on a regular basis for evaluating the efficacy of waste treatment technologies.Item Biomarker responses of Nile Tilapia (Oreochromis niloticus) exposed to polluted water from Kelani river basin, Sri Lanka: Implications for biomonitoring river pollution(Sri Lanka J. Aquat. Sci, 2018) Ruvinda, K.M.S.; Pathiratne, A.Biomarkers can be considered as early warning signals for potential adverse effects on the biota. The present study examined the feasibility of using selected biomarker responses of a model fish, Oreochromis niloticus under laboratory exposure approach for identification of potential biological impacts of pollution in Kelani River. Laboratory acclimated O. niloticus were exposed under static-renewal conditions to water samples collected from selected sites of the Kelani River basin with different anthropogenic influences and biomarker responses (brain and muscle cholinesterase activities for neurotoxicity, erythrocyte micronuclei and nuclear abnormalities for genotoxicity and liver histology for hepatic damage) were evaluated at 5 and 10 days of exposure. Exposed water was physico-chemically characterized using standard analytical methods. The results revealed that exposure of O. niloticus to the water from selected polluted sites which included canals and canal confluences resulted in significant increases (p<0.05) in total erythrocyte nuclear abnormalities, evolution of erythrocyte micronuclei and induction of liver histopathological indices in comparison to the fish exposed to the water from the upper reach of the river (reference site) in most cases and the control fish exposed to the aged tap water in all cases. Brain cholinesterase activity was significantly inhibited (p<0.05) in the fish exposed to the water from the most polluted site compared to the control fish exposed to the aged tap water. Biomarker responses indicated that the fish populations inhabiting the polluted sites in the river may be under stress especially due to hepatic damage and genotoxicity. Evaluation of “effect directed biomarker responses” of the model fish, O. niloticus following laboratory exposure to the contaminated water can be a practically feasible approach for biomonitoring potential pollution impacts associated with the riverine ecosystems.Item Assessing toxicity of inland surface waters impacted by industrial wastewater released from an export processing zone located near Kelani river basin using physic-chemical analysis and plant based bioassay(Sri Lanka Association for Fisheries and Aquatic Resources, 2016) Kuruppuarachchi, H.D.; Pathiratne, A.Item Bioassessment of selected water bodies in Sri Lanka using benthic oligochaetes with consideration of temporal variations(International Review of Hydrobiology, 2004) Pathiratne, A.; Weerasundara, G.A.Item Influence of temperatureand soil type on the toxicity of three pesticides to Eiseniaandrei(Chemosphere, 2009) de Silva, M.; Pathiratne, A.; Van Gestal, C.A.M.Expansion of agriculture in the tropics has increased the use of pesticides that may affect the soil ecosystems. Few studies so far determined the effects of pesticides in the tropics and tropical risk assessment therefore often relies on data from temperate conditions. Hence we compared the toxicity of chlorpyrifos, carbofuran and carbendazim to the earthworm Eisenia andrei at two different temperatures reflecting temperate and tropical conditions. The toxicity of the three pesticides in both conditions decreased in the order carbendazim > carbofuran > chlorpyrifos. For chlorpyrifos and carbofuran, but not for carbendazim, survival was more sensitive at the higher temperature, probably due to increased earthworm activity. Sub-lethal effects (reproduction and growth) however, varied inconsistently with temperature and soil types. We conclude that toxicity of pesticides in tropics may not be predicted from data generated under temperate conditions, even within the same species.