Correlation of arsenic and iron in groundwater of Bangladesh

Abstract

Water is a basic necessity of man along with food and air. In Bangladesh groundwater is a major source of safe water for drinking and other domestic purposes for the rural and urban population. Groundwater contains dissolved minerals such as iron, arsenic, manganese, nitrate, fluoride, chloride, calcium, sodium etc. Presence of elevated levels of arsenic in groundwater has become a major concern in Bangladesh and elevated levels of iron are also present in many regions of the country. This study is an attempt to evaluate the possible correlation between the presence of Arsenic and Iron in groundwater. Tn order to assess possible correlation between arsenic and iron concentration in groundwater, 760 tubewell water samples were analyzed. These tubewells covers the north-eastern zone of Bangladesh, and the districts of Manikg0rU and Noakhali. About 64 % of the tubewells contain iron above 1.0 mg/l and exceed Bangladesh standard and about 34 % of the tubewells contain iron exceeding 5.0 mg/I. About 34 % of the tubewells contain arsenic above 0.05 mg/l which is the Bangladesh standard for Arsenic. These tubewells are a potential threat to public health. The overall correlation between arsenic and iron concentration of tubewell water in the study-area in Bangladesh is poor. But in some districts a positive correlation has been observed and in some thanas the positive correlation is very strong. Arsenic concentration analysis of groundwater from 3912 tubewell water samples were performed and it was found that about 31 % of the tubewells in Bangladesh have arsenic concentration above 0.05 mg/I which poses a potential threat to public health. In general if Arsenic concentration is higher, Iron concentration is also higher.