Status of groundwater arsenic contamination in Bangladesh: A 14-year study report

• Published in: Water research (Oxford) 2010-11, Vol.44 (19), p.5789-5802
• Main Authors: Chakraborti, Dipankar, Rahman, Mohammad Mahmudur, Das, Bhaskar, Murrill, Matthew, Dey, Sankar, Chandra Mukherjee, Subhas, Dhar, Ratan Kumar, Biswas, Bhajan Kumar, Chowdhury, Uttam Kumar, Roy, Shibtosh, Sorif, Shahariar, Selim, Mohammad, Rahman, Mahmuder, Quamruzzaman, Quazi
• Format: Article
• Language: English
• Subjects: Approach for mitigation; Arsenic; Arsenic - analysis; Bangladesh; Contamination; Deep tubewells; Disasters; Drinking; Drinking water; Environmental Monitoring - statistics & numerical data; Flood plains; Fresh Water - chemistry; Geomorphological regions; Geomorphology; Groundwater; Hand tubewell; Number of hand tubewells; Population at risk; Spectrophotometry, Atomic; Time Factors; Water analysis; Water Pollutants, Chemical - analysis
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2010.06.051

Since 1996, 52,202 water samples from hand tubewells were analyzed for arsenic (As) by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) from all 64 districts of Bangladesh; 27.2% and 42.1% of the tubewells had As above 50 and 10 μg/l, respectively; 7.5% contained As above 300 μg/l, the concentration predicting overt arsenical skin lesions. The groundwater of 50 districts contained As above the Bangladesh standard for As in drinking water (50 μg/l), and 59 districts had As above the WHO guideline value (10 μg/l). Water analyses from the four principal geomorphological regions of Bangladesh showed that hand tubewells of the Tableland and Hill tract regions are primarily free from As contamination, while the Flood plain and Deltaic region, including the Coastal region, are highly As-contaminated. Arsenic concentration was usually observed to decrease with increasing tubewell depth; however, 16% of tubewells deeper than 100 m, which is often considered to be a safe depth, contained As above 50 μg/l. In tubewells deeper than 350 m, As >50 μg/l has not been found. The estimated number of tubewells in 50 As-affected districts was 4.3 million. Based on the analysis of 52,202 hand tubewell water samples during the last 14 years, we estimate that around 36 million and 22 million people could be drinking As-contaminated water above 10 and 50 μg/l, respectively. However for roughly the last 5 years due to mitigation efforts by the government, non-governmental organizations and international aid agencies, many individuals living in these contaminated areas have been drinking As-safe water. From 50 contaminated districts with tubewell As concentrations >50 μg/l, 52% of sampled hand tubewells contained As