Agrochemical exposure in Sri Lankan inland water systems

Abstract

Sri Lanka has undergone a number of development efforts over the last few decades, including the development of a series of water reservoirs in the central dry zone resulting in the expansion of primarily rice growing agricultural communities. These rapidly developed communities were built with shallow wells that are impacted by surface water runoff composition, which may intermittently contain significant amounts of agrochemicals as they are applied onto the fields. Chronic kidney disease of unknown etiology (CKDu) has been a growing threat in tropical low-land agricultural regions globally, including Sri Lanka, and agrochemical pollution is suspected as one of the factors in this disease. This study compares water quality parameters including target agrochemicals in a transect along the major Mahaweli River and across the local rice farming community of Wilgamuwa in the dry zone that receives water from Mahaweli reservoirs. The study shows elevated phosphate ,with and average phosphate concentration of 0.47 mg/L in Wilgamuwa wells compared to the US EPA water quality criteria of 0.05 mg/L. This study also shows 68% of sampled Wilgamuwa wells and 20% of Mahaweli water samples had agrochemicals above water quality guidelines. These results indicate some concern of Mahaweli water quality but primarily localized water contamination sources, and may help inform other studies of CKDu factors globally.