Magnitude of arsenic pollution in the Mekong and Red River Deltas - Cambodia and Vietnam
Large alluvial deltas of the Mekong River in southern Vietnam and Cambodia and the Red River in northern Vietnam have groundwaters that are exploited for drinking water by private tube-wells, which are of increasing demand since the mid-1990s. This paper presents an overview of groundwater arsenic pollution in the Mekong delta: arsenic concentrations ranged from 1-1610 mu g/L in Cambodia (average 217 mu g/L) and 1-845 mu g/L in southern Vietnam (average 39 mu g/L), respectively. It also evaluates the situation in Red River delta where groundwater arsenic concentrations vary from 1-3050 mu g/L (average 159 mu g/L). In addition to rural areas, the drinking water supply of the city of Hanoi has elevated arsenic concentrations. The sediments of 12-40 m deep cores from the Red River delta contain arsenic levels of 2-33 mu g/g (average 7 mu g/g, dry weight) and show a remarkable correlation with sediment-bound iron. In all three areas, the groundwater arsenic pollution seem to...