Toxic elements contamination in surface sediments of major tanks in Anuradhapura district; A CKDu endemic district in Sri Lanka

Farming occupants are the major victims of Chronic Kidney Disease of unknown etiology (CKDu) in North Central region, Sri Lanka. Tanks are the main source of water for farming and they act as sinks for agricultural run-offs. Environmental toxicants are adsorbed by bottom sediments and can be released into the adjacent water column due to environmental changes as those are not permanently bound. Therefore, this study attempts to determine the contamination situation of the selected toxic metals in sediments of the tanks in a CKDu prevalence distrct (Anuradhapura) in Sri Lanka and prediction of the risk. Sixteen tanks were selected and sediment samples were randomly collected from each tank from bank to center. Digested sediment samples were analyzed for heavy metals using Inductive Couple Plasma Mass Spectrometry and Calcium and Magnesium contents were analyzed using Atomic Absorption Spectrometry. According to the statistics, average values of some toxic metals such as As, Pb, and Cr in sediments were higher than severe effect levels (SEL) while most of the mean values of Cd, As, Pb, Cr, Zn, and Cu were beyond the Lowest effect levels (LEL). Apart from that, Geo Accumulation Indexes (I-geo) Indicate that almost all tanks in Anuradhapura district have moderately polluted with above mentioned pollutants. Hence, findings reveal about a risk generated on aquatic lives in the tanks as well as humans via food chain contamination with hazardous metals.