Extent and Severity of Arsenic Contamination in Soils of Bangladesh

Since arsenic in groundwater was recognized as a potential threat to human life, much effort has been directed towards ensuring safe drinking water either through mitigation techniques or through finding alternative water sources. Even when alternate sources of water are used for potable purposes, continued cropping of long-term irrigated soils subjected to As contaminated ground water will pose significant risk to animal and human health through soil-crop transfer of As. Food crops such as vegetables and cereals can become a path by which As may enter the food chain, because they can reflect the levels of As that exist in the environment in which they are cultivated (soil and irrigation water). Recent studies by Meharg et al. (2002) and Huq et al. (2001) demonstrate significant uptake of As by rice and a range of vegetable crops commonly grown in Bangladesh. Numerous greenhouse studies by a number of researchers have revealed that an increase in As in cultivated soils leads to an increase in the levels of As in edible vegetables (Burló et al., 1999; Carbonell-Barrachina et al., 1999; Helgensen and Larsen, 1999) with many complex factors affecting bioavailability, uptake and phytotoxicity of As (Carbonell-Barrachina et al., 1999). Although, there are many studies on As in Bangladesh few have focused on soil As. Considering this, a project was initiated among others, to assess the extent and severity of