Microcystin-LR Contamination Status and Physico-Chemical Water Quality Parameters of Five Selected Recreational Water Bodies in Sri Lanka

Microcystin-LR (MC-LR) is the most toxic and commonly encountered cyanotoxin variant in aquatic systems. MC-LR is a hepatotoxin, but evidences suggest that it might also induce kidney injury. There is an increasing trend in mortality due to chronic kidney disease (CKD) in Sri Lanka where the underlying cause of CKD remains complicated. Cyanobacterial toxins is considered as one of the possible reasons implicated in the aetiology of CKDu in Sri Lanka. A significant source of cyanobacterial toxin exposure is recreational use of contaminated freshwater bodies. Therefore, it was a timely need to assess MC-LR contamination status. Thus, in the present study, freshwater bodies of Beira, Boralesgamuwa, Kandy, Kurunegala and Hot water springs in Kinniya were sampled. Triplicate surface water samples were collected from each water body. Surface water temperature, pH, conductivity and dissolved oxygen (DO) were measured at the site itself and chemical analyses of nitrate, total phosphate and chlorophyll-a were carried out. Analysis of MC-LR contamination was done by Enzyme Link Immuno Sorbent Assay (ELISA). In this study, cyanotoxin MC-LR was not reported from Boralesgamuwa whereas all the other water bodies showed MC-LR contamination. The concentrations of MC-LR from the highest to the lowest were reported respectively from Beira lake (2198 ppb), Kandy lake (103 ppb), Kurunegala lake (75.6 ppb) and the Hot water springs (0.34 ppb). Results of the present study revealed that pH, nitrate, total phosphate and chlorophyll-a contents showed significant positive correlation with the MC-LR concentration of each water body (p<0.05) while surface water temperature, DO and conductivity did not show significant correlation to MC-LR contamination.