IRSPAS 2018
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Item Detection of cylindrospermopsin and microcystin-LR in well water of CKDu prevalent Medirigiriya, Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Abeysiri, H.A.S.N.; Wanigasuriya, K.; Manage, P.M.Cyanobacterial blooms in aquatic systems have increased over recent decades. Many of the blooms are highly toxic, causing a serious hazard to human and animal health. The commonest cyanotoxins are hepatotoxins such as microcystin-LR (MC-LR) and cylindrospermopsin (CYN). Cyanotoxin has been proposed as one of the causative agents for CKDu in Sri Lanka and recent studies have revealed the contamination of drinking dug wells by toxin-producing cyanobacteria in the North Central, Uva and Eastern provinces. Thus, the present study was carried out to determine the contamination of CYN and MC-LR in randomly selected CKDu patients’ household well water. The study was carried out for both dry and wet seasons and water samples were collected from 42 wells in Medirigiriya and 21 wells from Hambanthota as a control area. Water temperature, pH, conductivity, Dissolved Oxygen (DO) were measured at the site itself using standard methods. N-NO3-, N-NO2-, N-NH3, total phosphorous and total hardness were measured by standard spectrophotometric and titrimetric methods. CYN and MC-LR quantification were done using ELISA detection kits (Beacon) (minimum detection limit 0.1 ppb). Identification and enumeration of cyanobacteria were carried out under a light microscope (×400). The results of the study revealed that all the tested general water quality parameters were within the Sri Lanka standards given for potable water. Mean cell densities of Microcystis sp. were varying during dry season from 60 ± 0.03 cells/mL to 307 ± 0.08 cells/mL and from 48 ± 0.07 cells/mL to 127 ± 0.73 cells/mL during wet season where MC-LR ranged from 0.02 to 6.73 µg/L and from 0.01 to 5.34 µg/L during dry and wet seasons respectively. Mean cell densities of Cylindrospermopsis sp. during dry and wet season ranged between 20 ± 0.02 cells/mL to 82 ± 0.29 cells/mL and 14 ± 0.19 cells/mL to 76 ± 0.78 cells/mL respectively, whereas the mean concentrations of CYN during dry and wet season was between 0.38 ± 0.01 µg/L to 1.45 ± 0.08 µg/L and 0.27 ± 0.04 µg/L to 1.25 ± 0.08 µg/L. Cyanotoxins and cyanobacteria were not recorded from well water collected from Hambanthota. Principal Component Analysis was done for cyanotoxin concentration, water quality parameters and a number of CKDu patients in the study area and shows a positive relationship between cyanotoxin in wells and CKDu patients who consume water from the wells (p<0.05).Item Isolation of Salmonella spp. and Shigella spp. from ground and surface water in the lower part of the Kelani river basin: evaluation of resistance against selected antibiotics(2018) Abinaiyan, I.; Mahagamage, M.G.Y.L.; Manage, P.M.In recent years, greater attention has been paid by national and international agencies on microbial contamination of ground and surface water sources. Antibiotics are commonly used to treat emerging infectious diseases due to anthropological activities. Improper application of antibiotics both in human and animal therapy has become the main cause of antibiotic resistance. The Kelani River Basin (KRB) is the home to more than 25% of the Sri Lankan population and it provides about 80% of the drinking water to Greater Colombo. Thus, evaluation of the microbiological status along with antibiotic resistance is important to safeguard consumers within the KRB. Therefore, twenty ground and twenty surface water samples were collected from a lower part of KRB for the study during March 2018. Water temperature, Dissolved Oxygen (DO), pH and conductivity were measured at the site itself using standard meters and N-NO3−, N-NO2−, N-NH3, Total Phosphate (TP), COD and Total Hardness (TH) were measured by following standard spectrophotometric and titrimetric methods. Total Coliform (TC) and Fecal Coliform (FC) counts were obtained from membrane filtration methods where Salmonella spp. and Shigella spp. were isolated and identified according to the WHO standard protocol. Antibiotic resistance of the isolated Salmonella spp. and Shigella spp. were obtained using Antibiotic Susceptibility Test (AST) following Agar Disk Diffusion Method (ADDM) for some selected antibiotics by commercially available AST disk. Resistant strains were subjected to Broth Microdilution Assay (BMA) to find Minimum Inhibition Concentration (MIC). All the tested general water quality parameters were within the SLSI drinking water standard except pH and COD. It was found that; out of 40 samples, 39 were contaminated with TC and FC and 39 samples exceeded the bacteriological standards given by SLSI drinking water standards. Salmonella spp. and Shigella spp. were recorded in a groundwater sample located in Pattipola where poor sanitation practices were observed. Another sampling location in Kanampella, Shigella spp. was recorded. AST results of the study revealed that the Salmonella spp. and Shigella spp. were resistant to 10 µg/disk of Amoxicillin (AMX) and Ampicillin (AMP). The BMA indicates that MICs of the isolated strains against AMX and AMP were up to 70 µg/mL. Accordingly, treatment, awareness and strategic management plan is a must to safeguard both ground and surface water consumers in the lower part of the KRB.Item Biodegradation of Geosmin and 2-methylisoborneol by novel, native, Gram negative bacteria in Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Ganegoda, S.S.; Chinthaka, S.D.M.; Manage, P.M.Trans-1, 10-dimethyl-trans-9-decalol (Geosmin) and 2-methylisoborneol (2-MIB) are key compounds which cause taste and odour (T and O) issues in drinking water. Despite no recorded health hazards, consumers reject the water if these odorants are present, due to their unpleasant earthy and musty T and O. Hence, removing Geosmin and 2-MIB from drinking water is a necessity for worldwide water authorities and consumers. Biodegradation has been widely recognized as effective for the removal of these compounds. Biodegradation of Geosmin and 2-MIB was investigated using native bacteria isolated from water and soil from 12 raw water bodies where the drinking water T and O issues are prevailing. Accordingly, five districts: Anuradhapura, Pollonnaruwa, Ampara, Batticaloa and Trincomalee were selected. Isolation of Geosmin and 2-MIB degrading bacteria in water and in sediment were carried out using standard microbiological procedures following enrichment, isolation and screening of potential degraders using Biolog MT2 plate assay. Potential Geosmin and 2- MIB degraders were subjected to degradation kinetics study and identification was carried out using 16S rRNA sequencing. Morphologically different 150 bacteria colonies from Geosmin treated samples and 75 colonies from 2-MIB treated water samples were isolated. Among them, 23 and 9 bacteria were identified as positive Geosmin and 2-MIB degraders respectively using the Biolog MT2 plate assay. Five bacteria showed complete degradation of Geosmin (initial level 20 ppt) at 7 days of incubation and they were identified as Myroides odoratimimus, Providencia rettgeri, and Proteus mirabilis. P . mirabilis isolated from Tissa wewa water, showed 100% degradation of Geosmin (initial level 20 ppt) at 5 days with a half-life time of 3 days when compared to control and other bacteria species. P . rettgeri isolated from Nuwara wewa soil, showed 100% degradation of 2-MIB (initial level 20 ppt) at 4 days incubation having 2 days of half-life time. P . mirabilis and P . rettgeri were previously reported antibiotic and xenobiotic degraders, and this is the first report of them, regarding degradation of Geosmin and 2-MIB.