Browsing by Author "Ruvinda, K.M.S."

Now showing 1 - 4 of 4

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.
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.
Effect of Titanium dioxide nanoparticles on tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider 1799)
(Institute of Biology, Sri Lanka, 2013) Ruvinda, K.M.S.; Pathiratne, A.
Use of erythrocytic nuclear abnormalities of feral fish species as biomarkers for assessing potential genotoxic impacts in Kelani River
(Faculty of Graduate Studies, University of Kelaniya, 2015) Ruvinda, K.M.S.; Pathiratne, A.
Nuclear abnormalities in the peripheral erythrocytes of fishes inhabiting contaminant waters are useful biomarkers for assessing genotoxic potential of surface waters impacted by anthropogenic contaminants. Kelani river which receives a wide variety of contaminants from multiple sources including industrial effluents and domestic waste, is ranked as the most polluted river in Sri Lanka. However, scientifically based evidences on biological impacts of Kelani river pollution on its resident fauna are meagre. In the present study, frequencies of erythrocytic nuclear abnormalities in the two fish species inhabiting Kelani river viz. Etroplus suratensis and Dawkinsia singhala were evaluated in order to assess the potential genotoxic impacts. E. suratensis were sampled from Ruwanwella (upstream) and Mattakkuliya (seaward site) sites, whereas D. singhala were sampled from the sites located in Ruwanwella and Kaduwela (between upstream and seaward site) during the years 2013-2015 covering dry and wet periods. Erythrocytic nuclear abnormalities in the blood of sampled fishes were evaluated using standard procedures. In addition, surface waters of the fish sampling sites were physico-chemically characterized using standard analytical procedures. Water quality parameters indicated high levels of chemical oxygen demand and heavy metal levels in Mattakkuliya and Kaduwela sites in comparison to Ruwanwella site. Despite temporal variations, frequencies of total erythrocytic nuclear abnormalities were significantly higher in the E. suratensis sampled from Mattakkuliya site than those from Ruwanwella site (P <0.05). In addition, D. singhala sampled from Kaduwela site had significant total erythrocytic nuclear abnormalities than the fish from Ruwanwella site. Of the four types of nuclear abnormalities detected, blebbed and noched nuclei contributed mainly to the induction of total erythrocytic nuclear abnormalities than binuclei and nuclear buds. Comparison of erythrocytic nuclear abnormalities of the two feral fish species inhabiting Kelani river together with physico-chemical analysis revealed that Mattakkuliya and Kaduwela sites of the Kelani river are polluted with genotoxic contaminations which can induce harmful impacts on indigenous fauna. This study was funded by the National Research Council research grant 11-11 and National Science Foundation equipment grant RG/2011/EQ/16.