The relation between arsenic content and reductive chemical compounds in groundwater at the Red River banks in Hanoi area

Abstract

The high arsenic content is likely related to the reductive characteristic of groundwater. The arsenic content and reductive chemical compounds in groundwater were evaluated, the studied water samples were collected from tube wells in both the Red River banks in Hanoi. The representative reducing components in groundwater including ammonium, dissolved organic carbon and methane were studied. The results showed that the groundwater at the right bank (Thanh Trì district) has a stronger reductivity than at the left bank (Gia Lam district) of the Red River. The concentration of arsenic in groundwater in the right bank was also higher than that in the left bank. This suggests that the reductive environment of the groundwater was favourable for the release of arsenic from sediment into groundwater. Besides, the pumping process in the urban Hanoi also affected the release of arsenic into groundwater.