Zoology
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Item Bioassessment of the Effluents Discharged from Two Export Oriented Industrial Zones Located in Kelani River Basin, Sri Lanka Using Erythrocytic Responses of the Fish, Nile Tilapia (Oreochromis niloticus)(Springer US., 2017) Hemachandra, C.K.; Pathiratne, A.Complex effluents originating from diverse industrial processes in industrial zones could pose cytotoxic/genotoxic hazards to biota in the receiving ecosystems which cannot be revealed by conventional monitoring methods. This study assessed potential cytotoxicity/genotoxicity of treated effluents of two industrial zones which are discharged into Kelani river, Sri Lanka combining erythrocytic abnormality tests and comet assay of the tropical model fish, Nile tilapia. Exposure of fish to the effluents induced erythrocytic DNA damage and deformed erythrocytes with serrated membranes, vacuolations, nuclear buds and micronuclei showing cytotoxic/genotoxic hazards in all cases. Occasional exceedance of industrial effluent discharge regulatory limits was noted for color and lead which may have contributed to the observed cytotoxicity/genotoxicity of effluents. The results demonstrate that fish erythrocytic responses could be used as effective bioanalytical tools for cytotoxic/genotoxic hazard assessments of complex effluents of industrial zones for optimization of the waste treatment process in order to reduce biological impacts.Item Cytogenotoxicity screening of source water, wastewater and treated water of drinking water treatment plants using two in vivo test systems: Allium cepa root based and Nile tilapia erythrocyte based tests(Pergamon., 2017) Hemachandra, C.K.; Pathiratne, A.Biological effect directed in vivo tests with model organisms are useful in assessing potential health risks associated with chemical contaminations in surface waters. This study examined the applicability of two in vivo test systems viz. plant, Allium cepa root based tests and fish, Oreochromis niloticus erythrocyte based tests for screening cytogenotoxic potential of raw source water, water treatment waste (effluents) and treated water of drinking water treatment plants (DWTPs) using two DWTPs associated with a major river in Sri Lanka. Measured physico-chemical parameters of the raw water, effluents and treated water samples complied with the respective Sri Lankan standards. In the in vivo tests, raw water induced statistically significant root growth retardation, mitodepression and chromosomal abnormalities in the root meristem of the plant and micronuclei/nuclear buds evolution and genetic damage (as reflected by comet scores) in the erythrocytes of the fish compared to the aged tap water controls signifying greater genotoxicity of the source water especially in the dry period. The effluents provoked relatively high cytogenotoxic effects on both test systems but the toxicity in most cases was considerably reduced to the raw water level with the effluent dilution (1:8). In vivo tests indicated reduction of cytogenotoxic potential in the tested drinking water samples. The results support the potential applications of practically feasible in vivo biological test systems such as A. cepa root based tests and the fish erythrocyte based tests as complementary tools for screening cytogenotoxicity potential of the source water and water treatment waste reaching downstream of aquatic ecosystems and for evaluating cytogenotoxicity eliminating efficacy of the DWTPs in different seasons in view of human and ecological safety.Item Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries(Academic Press., 2016) Hemachandra, C.K.; Pathiratne, A.Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure.Item Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of industrial effluents originated from different industrial activities(Springer International Publishing., 2015) Pathiratne, A.; Hemachandra, C.K.; De Silva, N.Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of treated effluents originated from four types of industrial activities (two textile industries, three rubber based industries, two common treatment plants of industrial zones, and two water treatment plants) was assessed. Physico-chemical parameters including the heavy metal/metalloid levels of the effluents varied depending on the industry profile, but most of the measured parameters in the effluents were within the specified tolerance limits of Sri Lankan environmental regulations for discharge of industrial effluents into inland surface waters. In the A. cepa test system, the undiluted effluents induced statistically significant root growth retardation, mitosis depression, and chromosomal aberrations in root meristematic cells in most cases in comparison to the dilution water and upstream water signifying effluent induced cytotoxicity and genotoxicity. Ethyl methane sulphonate (a mutagen, positive control) and all the effluents under 1:8 dilution significantly induced total chromosomal aberrations in root meristematic cells in comparison to the dilution water and upstream water indicating inadequacy of expected 1:8 dilutions in the receiving waters for curtailing genotoxic impacts. The results support the use of a practically feasible A. cepa test system for rapid screening of cytotoxicity and genotoxicity of diverse industrial effluents discharging into inland surface waters.Item Assessing toxicity of copper, cadmium and chromium levels relevant to discharge limits of industrial effluents into inland surface waters using common onion, Allium cepa bioassay(Springer US., 2015) Hemachandra, C.K.; Pathiratne, A.Toxicity of copper, cadmium and chromium relevant to established tolerance limits for the discharge of industrial effluents into inland surface waters was evaluated by Alliumcepa bioassay. The roots of A. cepa bulbs exposed to Cu2+ (3 mg L−1) individually or in mixtures with Cd2+ (0.1 mg L−1) or/and Cr6+ (0.1 mg L−1) exhibited the highest growth inhibition, mitotic index depression and nuclear abnormalities. Root tip cells exposed to Cr6+ or Cd2+ alone or in mixture displayed significant chromosomal aberrations in comparison to the controls. EC50s for root growth inhibition followed the order Cu2+ < Cd2+ < Cr6+ indicating greater toxicity of copper. The results show that the industrial effluent discharge regulatory limits for these metals need to be reviewed considering potential cyto-genotoxicity to biological systems.Item Heavy metal levels in water and sediments of Bathalagoda Reservoir, Sri Lanka(Sri Lanka Association for Fisheries and Aquatic Resources, 2010) Hemachandra, C.K.; Pathiratne, A.; Pathiratne, K.A.S.Bathalagoda reservoir, a fresh water body located in the Kurunegala District of Sri Lanka is used by the residents in the area for irrigating paddy fields, drinking and bathing purposes and for culture-based fisheries. The present study was carried out to determine the selected heavy metal levels viz. lead, cadmium and copper in water and sediments of the reservoir to assess the extent of heavy metal pollution. Water and sediment samples were obtained from three locations of the reservoir namely Ibbagamuwa, Moragolla and Madihe- Mudunduwa during the period September 2007 - July 2009 and the heavy metal levels were determined by Atomic Absorption Spectrometry following standard procedures. The results showed that lead, cadmium and copper levels in water ranged from not detectable level to 2 g L", not detectable level to 3 g L" and not detectable level to 3 g L" respectively. Corresponding metal levels in the sediments (dry weight basis) ranged from not detectable level to 523 g g", not detectable level to 0.1 g g" and not detectable level to 26 g g" respectively. Significant site specific variations or seasonal variations were not observed in relation to the heavy metal levels in water and sediments of the reservoir. The results revealed that the levels of lead, cadmium and copper in the reservoir water are far below the maximum permissible levels specified by the international regulatory authorities (World Health Organization and United States Environmental Protection Agency) for drinking water and water used for irrigation purposes.Item Histopathology of gills and liver tissues of Nile tilapia inhabiting Bolgoda North Lake, Sri Lanka(Sri Lanka Association for Fisheries and Aquatic Resources, 2010) Hemachandra, C.K.; Pathiratne, A.Bolgoda North Lake. an urban water body located in the Western Province of Sri Lanka is becoming polluted with anthropogenic chemicals including heavy metals and toxic organic pollutants such as polycyclic aromatic hydrocarbons. Histopathological lesions can be used as indicators for the effects of various anthropogenic pollutants on fish and are a reffection of the overall health of the entire fish population in the aquatic ecosystem. The present study was carried out to investigate the histological structure of gill and liver tissues of Nile tilapia (Oreochromis nifoticus), a food fish inhabiting 60lgoda North Lake to evaluate the general health status of the fish population. The tissue samples were taken from the fish inhabiting the Lake during September 2007 to July 2009 and histological sections of the gill and liver tissues were prepared according to the standard methodologies. In addition serum sorbitol dehydrogenase (SDH) enzyme activities in the fish were determined to evaluate the chemically induced liver damage. Several histological alterations in gill tissues viz. hyperplasia in primary and secondary lamellae, fusion of primary and secondary lamellae, mucous cell proliferation, necrosis in lamellar epithelial cells, lamellar hypertrophy, clubbing at the tips of secondary lamellae, and telangiectasis were observed in most of the fish examined. Epithelial hyperplasia in secondary lamellae and mucous cell proliferation were the most abundant types of lesions in the gill tissues of sampled fish. In addition metacercarian parasitic cysts in the gill tissue were observed in some of the fish examined. The liver tissues of the fish showed prominent histological alterations including swelling of hepatocytes, pyknosis of hepatocytes nuclei, breakdown of liver cell walls, cytoplasmic vacuolation, focal and zonal necrosis, fibrosis in the hepatic tissue, melano macrophage aggregates, vacuoles in the pancreatic tissue and bile duels, pancreatic cell necrosis, and sinusoidal congestion in the blood vessels & central veins. Cytoplasmic vacuolation, focal cell necrosis and melano macrophage aggregates were the most common types of liver lesions observed in the fish. Histopathological alterations in gill and liver tissues of Nile tilapia indicate that the fish population residing in 60lgoda North Lake is under threat due to chemical contamination. Elevated serum SDH enzyme activities in the blood of the examined fish confirmed chemically induced liver damage.Item Screening toxicity of selected industrial effluents reaching Kelani River, Sri Lanka using Allium cepa (Common onion) bioassay(Sri Lanka Association for the Advancement of Science, 2013) Hemachandra, C.K.; Pathiratne, A.Item pplication of Allium cepa (Onion) bioassay for assessing toxicity of copper, cadmium and chromium at the concentrations established as national tolerance limits for the discharge of industrial effluents into inland surface waters(Sri Lanka Association for the Advancement of Science, 2013) Hemachandra, C.K.; Pathiratne, A.Item Detection of genotoxic effects in peripheral erythrocytes of Nile tilapia (Oreochromis niloticus) following exposure to selected industrial effluents using alkaline common assay and micronucleus test(Institute of Biology, Sri Lanka, 2013) Hemachandra, C.K.; Pathiratne, A.