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Item Cyto-genotoxicity and quality of sediments in Dandugan Oya, Sri Lanka(Proceedings Of Tile 38th Annual, Sessions Of The Institute Of Biology, 2018) Wadasinghe, L.G.Y.J.G.; Wijeyaratne, W.M.D.N.Sediments are very important in maintaining aquatic ecosystem health. Dandugan Oya is a stream located in the Western province of Sri Lanka. Dandugan oya receives industrial waste from multiple sources. It also serves as a raw water source for public water supply in some suburban areas in the Gampaha District. This study was conducted with the objective of assessing sediment quality and cyto-genotoxic effects of sediments in Dandugan oya. Shallow sediments (5 replicates) were collected from six sites CA: Urban site; B and D: Industrial sites; C: water intake for public water supply; E: Agricultural site; F: Reference site) at two month intervals from May to November 2017 and sediment quality was analysed using standard analytical methods. Cyto-genotoxicity of the sediment elutriates were assessed using Allium cepa bioassay. Spatial variation of sediment quality and toxicity indices were analysed by ANOVA followed by Tukey's pairwise comparison using MINITAB 14 software. Significant spatial variations of sediment quality parameters and nuclear abnormalities were observed. Site B recorded significantly lower sand (37%) and significantly higher silt contents (44%) while site D showed a significantly higher clay content (40.6%). Significantly lower sediment pH (4.71) and sediment conductivity (25.29 VLS/cm) were recorded from reference site and highest total organic matter (2.32 %) content was recorded at urban site. Mean nuclear abnormalities ranged from 130/00 to 440/00 with significantly higher abnormalities in sites B (42%)) and D (440/00). Occurrence of nuclear buds and condensed nuclei in the interphase cells of the Allium cepa root tips exposed to sediment elutriates from industrial sites (150/00 and 180/00) were significantly higher (7 to 9 fold) compared to reference site. Further, Site B showed the highest condensed nuclei formation (610/00). However, occurrence of binuclei showed no significant spatial variations, The Mitotic index of the Allium cepa root tip cells ranged from 2.9% to 7.4% with significantly higher values in sites A and B, The results of the present study indicated the occurrence of potential cyto-genotoxic contaminants in the sediments of Dandugan Oya. Therefore, further investigations on the identification of the active forms of these contaminants are recommended in order to maintain the health of the ecosystem.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 Assessing potential biological hazards associated with Kelani River water using Nile tilapia (Oreochromis niloticus) as an aquatic model species(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Ruvinda, K.M.S.; Pathiratne, A.Kelani River receives complex mixtures of pollutants from diverse sources which include waste from industries, agriculture, domestic and municipal sources. However, scientifically based evidences on biological impacts associated with the Kelani River water are limited. Nile tilapia (Oreochromis niloticus) is a practically feasible aquatic model for toxicological assessments under tropical conditions. The present study assessed erythrocytic nuclear abnormalities (ENA), hepatic ethoxyresorufin O-deethylase (EROD) and hepatic glutathione S-transferase (GSTs) activities of Nile tilapia following exposure to selected surface water samples collected from the Kelani River and its tributaries in order to assess the potential biological impacts. Fingerlings of fish were exposed to surface water samples from an industrial effluent receiving canal (Menikagara ela; Site B), canal confluent (Site M), downstream of Kelani river at Sedawatta (contaminated with oil installation complex effluents and house hold waste; Site S) and up stream of Kelani river at Ruwanwella (reference site; Site R) and aged tap water (as controls) for 10 days under static renewal conditions. Physico-chemical parameters of exposed water were measured using standard analytical methods. Blood and liver samples of the exposed fish were collected from each treatment after 5 and 10 days of exposure, and ENA and EROD and GST tests were performed using standard methods. Water quality parameters indicated high levels of chemical oxygen demand, biochemical oxygen demand, total dissolved solid, salinity and conductivity and elevated levels of total phosphate content, nitrate content, heavy metal Cr, Cu and Pb levels in the water collected from the Sites B, M and S compared to tap water (P <0.05). Frequencies of total ENA were significantly higher in the fish exposed to water from the sites B, M and S compared those of the fish exposed to the tap water for 5 and 10 days. Blebbed and notched nuclei contributed mainly to the induction of total ENA than micronuclei and nuclear buds. Total number of nuclear abnormalities was elevated by the 10th day of exposure. Hepatic EROD and GST activities of the fish exposed to polluted water were not significantly different (P >0.05) from those of the fish exposed to tap water, but the enzyme activities were increased in each treatment at 10th day of exposure. Comparison of nuclear abnormalities and hepatic EROD & GST activities of O. niloticus together with physico-chemical analysis revealed that Sites B, M and S of Kelani River are contaminated with organic and inorganic xenobiotics, which may pose harmful cyto-genotoxic impacts on the feral fish populations.