Arsenic contamination in irrigation tube wells

Abstract

The presence of arsenic (As) in groundwater is a wide-spread problem in south-east newlineAsia, especially West Bengal (India) and Bangladesh. Water quality and chemistry of the newlinegroundwater have been investigated by a systematic screening operation of tube wells in newlinea locality in West Bengal (India). Drinking water has always been considered as the newlinemajor ingestion route of arsenic (As) to human system. Simultaneously, soil and crops newlinehave now drawn more attention due to transfer of As in the food chain via groundwater- newlinesoil-plant system. Several attempts (mostly hypothesis) have been made to find out the newlineprimary (origin) and secondary (mobilization) causes of this natural calamity (high As newlinegroundwater) and the spatial distribution pattern. In addition, the regional extension of newlinethe As distribution anomaly (spatio-temporal heterogeneity of As patches) has also been newlinesignificantly noticed in various part of the Bengal Delta Plain (BDP). The magnitude of newlinethe problem is momentous and unprecedented, causing a serious threat to the health of newlineseveral millions of peoples by arsenic induced diseases. The groundwater As newlineconcentration very often exceeds the normed national drinking water standards (10 and#956;g/L newlineand 50 and#956;g/L where no other option is available) as well as the WHO guideline value (10 newlineand#956;g/L). Sporadic cases of arsenicosis (and other As induced diseases) were firstdiscovered in the mid eighties in West Bengal, India, and it is also widespread in the newlineneighbouring areas of Bangladesh. The spatial distribution of As in the in the vast alluvial newlinedeposits of BDP does not follow any specific trend and is often very heterogeneous, with newlineirregularly distributed As-rich pockets over the whole area. In BDP, the spatial newlinedistribution of groundwater newline