Climatic Influences on Arsenic Health Risk in the Metamorphic Precambrian Deposits of Sri Lanka: A Re-analysis-based Critical Review

The present study examines the arsenic associated human health risk in Sri Lanka with due consideration to age and gender vulnerability. While the existing low-grade metamorphic rock carries less possibility of arsenic contamination, the usage of old generation arsenical pesticides may increase the future possibility of a catastrophe. Through a comprehensive Health Risk Index (HRI) it could be seen that the north part of the country carries higher risk for children below eight years of age to develop cancer in long run. Interestingly rainfall pattern correlates with arsenic vulnerable zones, denoting that high monsoon led recharge may prevent rapid anthropogenic fluctuations in anoxic zones thereby preventing vigorous formation of oxy-hydroxides. However, the possibility of sea-water intrusion due to excessive groundwater abstraction may change the major-ion chemistry soon which may impact the co-occurrence scenario of arsenic and fluoride. In this regard the study identifies the wetter regions and their shift from 1981 to 2018 to propose a more stable groundwater regime in terms of sea water intrusion. There exist few scientific literatures concerning the occurrence of arsenic in the groundwater of Sri Lanka but there exists no framework to provide a meaningful interpretation by combining all the available research outputs. The present study therefore provides a basis for understanding the existing groundwater arsenic contamination of Sri Lanka by providing a scientific framework to the studies done so far by various researchers in the past 30 years.