Arsenic and other toxic elemental contamination of groundwater, surface: Water and soil in Bangladesh and its possible effects on human health

The problems of contamination caused by arsenic (As) and other toxic metals in groundwater, surface water and soils in the Bengal basin of Bangladesh have been studied. Altogether 10 groundwater, seven surface water and 31 so il samples were collected from arsenic-affected areas and analysed chemical ly. The geologic and anthropogenic sources of As and other toxic metals are discussed in this paper. The chemical results show that the mean As concen trations in groundwater in the Char Ruppur (0.253 mg As L-1), Rajarampur (1 .955 mg As L-1) and Shamta areas (0.996 mg As L-1) greatly exceed the WHO r ecommended value, which is 0.01 mg As L-1. The concentrations of As in grou ndwater are very high compared to those in surface water and in surface soi l in the three (As-affected) areas studied. This indicates that the source of As in groundwater could be bedrock. The relatively high concentrations o f Cr, Cu, Ni, Ph and Zn in surface water, compared to world typical value, are due to the solubility of metal ions, organometalic complexes, coprecipi tation or co-existance with the colloidal clay fraction. In the soil, the e levated concentrations of As, Cr, Cu, Ni, Ph and Zn are due to their strong affinity to organic matter, hydrous oxides of Fe and Mn, and clay minerals .