Arsenic contamination in groundwater and its possible sources in Hanam, Vietnam
This study investigated the arsenic (As) level in groundwater, and the characteristics of aquifer sediment as related to the occurrence of As in groundwater in Hanam, Vietnam. The deposition and transport of As-containing substances through rivers were also examined. Arsenic concentrations in 88% of the groundwater samples exceeded the As limit for drinking water based on the WHO standards. The dominating form of arsenic was As(III). The maximum total As content in bore core sediment was found in a peat horizon of the profiles and generally, elevated levels of As were also found in other organic matter-rich horizons. Total As contents of the bore core sediments were significantly correlated with crystalline iron oxide, silt and clay contents, suggesting that As in aquifer sediment was mainly associated with iron (hydr)oxides and clay mineral. In the groundwater, As concentration showed significant correlations with the total concentrations of Fe and HCO3 -. Significant c...