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Item Assessment of selected water quality Parameters in well water samples from Chronic Kidney Disease of unknown etiology (CKDu affected Unagaswewa area(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Jayasekera, L. D. H. S.; Mathota-Arachchige, Y. L. N.Chronic Kidney Disease of unknown etiology (CKDu) is a serious condition of kidney failure and is not associated with conventional risk factors. The disease is increasingly spreading over many areas of Sri Lanka. The exact causative factors and etiology of CKDu are not yet completely understood . However, based on observations of previous research, there are strong evidences to show that CKDu has a profound relationship with the quality of drinking water . Therefore, this research study was conducted to evaluate the water quality of well water samples from Unagaswewa area and thus to assess the suitability of well water for drinking purpose, with respect to the World Health Organization guidelines and Sri Lanka Standards of drinking water quality . Unagaswewa grama niladari division of Medawachchiya divisional secretariat was taken as the study area of the research . Random stratified sampling method was used for sample collection . A clinical survey was performed to find the number of patients and non-patients living in a household and other necessary background information were also collected . Fifteen water samples were collected from well water sources and two Reverse Osmosis (RO) filtered water samples were used as a tentative reference. The water quality parameters such as pH (5.56 7.53), electrical conductivity (EC) (15.13 2540.00 µS/cm), total dissolved solids (6.94 1290.00 mg/L), concentrations of Calcium (0.00 111.00 mg/L) and Potassium (0.00 5.08 mg/L), total hardness (2.00 1080.00 mg/L) and total alkalinity (40.00 546.00 mg/L) were measured by averaging the triplicated results. The samples were analyzed using different analytical techniques and instruments such as multi parameter analyzer (HACH: HQ 40d multi), flame photometer (Jenway PFP7) and titrimetric methods . Based on all the measured water quality parameters in the study area, RO filtered water samples were identified as suitable for drinking purposes except that the pH is slightly below the recommended values, which can be predicted due to an ion exchange during the filtration. Among the well water samples collected from Unagaswewa area, more than 85% of the samples were identified as not suitable for drinking. Based on the measured parameters, it can be stated that, well water in Unagaswewa area can be used for drinking purposes upon RO filtration, which will be further confirmed by the completion of the analysis.Item Sensitivity of four freshwater animal species to copper and cadmium under tropical temperature exposure(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Heshani, A.L.S.; Pathiratne, A.Copper and cadmium are two common pollutants in Sri Lankan freshwater ecosystems. Water quality criteria for these metals focusing on the protection of freshwater species in Sri Lanka are yet unavailable. Formulating water quality criteria based on tropical species sensitivity distribution analysis would require credible ecotoxicity data (especially at early life/young stages) under tropical temperature exposure for a range of freshwater species belonging to different trophic levels. Thus, objective of the present study was to generate freshwater ecotoxicity data for copper and cadmium for tropical temperature exposures using four freshwater native/model test organisms: two crustaceans, Daphnia magna and Moina macrocopa, the fish Poecilia reticulata and the tadpoles of Duttaphrynus melanostictus representing primary and secondary consumers. Based on the range finding tests, the animals were exposed separately to a series of concentrations of Cu2+ (D . magna 50-300; M . macrocopa 1-150; fish 25-300; tadpole 10-300) or Cd2+ (D . magna 10-200; M . macrocopa 1-150; fish 25-300; tadpole 100-500) in μg/L along with the controls (in triplicate/quadruplicate exposure medium, n=10 animals per replicate) at 280C - 300C under static-renewal conditions (hardness ≤ 66 mg/L as CaCO3) following standard OECD toxicity testing protocols. The sensitivity of the crustaceans (neonates) for different concentrations of Cu2+ and Cd2+ exposure was assessed based on percentage neonates immobilized whereas the sensitivity of P . reticulata (fry 5-10 mm total length) and D . melanostictus (Gosner stage 25 tadpoles) was evaluated based on percent mortality. Concentrations of copper and cadmium in the exposure media were determined using atomic absorption spectrophotometry. Ecotoxicity thresholds were estimated based on concentration-toxicity response relationships using USEPA software, ‘Toxicity Relationship Analysis Program’. Estimated 48 hour median effective concentration (EC50) of copper for immobilization of the crustaceans, D . magna and M . macrocopa were 117 and 15 μg/L respectively whereas corresponding values for cadmium were 45 and 12 μg/L. Estimated 96 hour median lethal concentration (LC50) values of copper for the fish, P . reticulata and the tadpole, D . melanostictus were 63 and 72 μg/L respectively. Corresponding LC50 values for cadmium were 76 and 431 μg/L. The most sensitive species for copper and cadmium was the crustacean, M . macrocopa . The highest tolerance for cadmium was shown by the amphibian, D . melanostictus tadpole whereas D . magna showed the highest tolerance to copper. Additional ecotoxicity data for copper and cadmium focusing on more tropical freshwater species are needed for derivation of water quality criteria for tropical freshwater life protection.Item Toxicity of aqueous extract of white hoary pea, Tephrosia candida (Papilionoideae) on Nile tilapia, Oreochromis niloticus (Cichlidae) fingerlings(Sri Lanka Association for Fisheries and Aquatic Resources, 2016) Mohotti, C.R.W.C.; Epa, U.P.K.Fish poisoning using Tephrosia candida, which is an exotic plant to Sri Lanka is taking place in streams in the boundary of the Sinharaja forest, a tropical forest range, designated as a world heritage site by UNESCO in 1988. T. candida is a source of flavonoids and rotenoids including rotenone, tephrosin, and deguelin. Fishermen add large amounts of grounded plant matter to kill almost all the fishes in the stream within a short period of time. This method of unregulated fishing may have a long term negative effect on fish diversity and abundance in the area. A 96 h static renewal toxicity bioassay was carried out in the laboratory to determine the median lethal concentration (LC50) of aqueous extract of T. candida leaves on Oreochromis niloticus fingerlings. Experimental fish were exposed to test water in 20 L glass aquaria with concentrations of plant extract of 5, 7.5, 10, 15 and 20 mg L-1. All five treatments aquaria and the control aquaria without plant extract were triplicated. Fish exposed to plant extract showed symptoms of toxicity including, initial inactivation, agitated swimming, turning movement, air gulping, increased opercular movement followed by erratic swimming, loss of reflex, slow opercular movement, setting at the bottom motionless and knockdown before death. The gills of the dead fishes were damaged, swollen and external bleeding were observed. Lower concentrations of the extracts had sub lethal effects which manifested as zigzag movement, air gulping, increased opercular movement and some fish gathered near the air stones. The LC50 values at various exposure periods were 10.83 mg L-1 for 24 h; 8.61 mg L-1 for 48 h; 7.26 mg L-1 for 72 h and 6.43 mg L-1 for 96 h. It could be concluded that the application of T. candida extract causes lethal toxic effects on fish even at very low concentrations.