West Bengal || Bangladesh
Middle Ganga Plain, Bihar ||
BackgroundIn June 2002 a primary school teacher in Kolkata hailing from Semria Ojhapatti village, Bhojpur district, Bihar, India, came to our Department, School of Environmental Studies (SOES) to analyze his hand tubewell water sample. He was worried over a possible toxic cause of the liver disease and skin lesions of his family in Bihar. At first we declined to accept the sample since the container was not properly washed and there was no added preservative. But he requested us to receive his sample as he was coming from a long distance. Then we received the sample and analyzed by Flow Injection – Hydride Generation – Atomic Absorption Spectrophotometer (FI- HG- AAS) technique in our laboratory. The sample contained 814 mg/L of arsenic. We thought the container could be contaminated from any other sources. When he came to receive the analysis report we discussed how he collected the sample and his family background. We showed him photographs of arsenical skin lesions and he noted that his family and the neighbors had similar lesions, as had his first wife, who had died of cancer. The School teacher, who lived in Kolkata and visited his family every 6 months for 2-3 weeks, had no arsenical skin lesions. After this incident we collected and analyzed 159 hand tubewell water samples from his village (Semria Ojhapatti village is about 600 km from Calcutta and about 50 km from Patna, the capital of Bihar and close to Ganga). Analysis of 159 samples from the village showed such high concentrations of arsenic that a study was initiated to investigate arsenic contamination in Bihar . The present communication describes the groundwater arsenic contamination status in 12 districts in the middle Ganga plain of Bihar.
We started our survey in Bihar in June 2002. At that time we found 6 affected villages in one block Shahpur of Bhojpur district . But with time, an increasing number of arsenic affected districts, blocks and villages are being discovered. In our study for over last 4 years hand tubewell water samples were collected at random from 12 districts of Bihar. To date, we have analyzed 19,961 hand tubewell water samples from 42 blocks, 164 GPs and 398 villages / wards. On the basis of this analysis we found arsenic concentration above 10 mg/L (WHO guideline value for arsenic in drinking water) in 310 villages, 39 blocks and in 235 villages, 36 blocks above 50 mg/L (Indian standard for arsenic in drinking water). The summary of groundwater arsenic contamination status in Bihar is presented in the Table below . From the Tables , it appears that al the 12 districts situated in the side of river Ganga are highly arsenic contaminated, notably 908 (4.55 %) tubewells contain arsenic above 300 mg/L. Chakraborti et al and Rahman et al observed that there is positive possibility of arsenical skin lesions to those drinking water contaminated with arsenic 300 mg/L and above for a couple of years . We have also found 92 (0.46%) tubewells having arsenic concentration above 1000 mg/L. Highest arsenic concentration in groundwater was found 2100 mg /L in the village Harail Chapar of Samastipur district (shallow depth).
*During our last 20 years field experience in West Bengal and 10 years in Bangladesh we have observed that ingestion of arsenic contaminated water with 300 mg/L for prolonged period may cause arsenical skin lesions. We also described in our earlier paper.We have predicted that the northern part of the river close to Terai Region could be arsenic affected.
Arsenic Groundwater Contamination in Middle Ganga Plain, Bihar, India: A Future Danger - Dipankar Chakraborti, Subhash C. Mukherjee, Shyamapada Pati, Mrinal K. Sengupta, Mohammad M. Rahman, Uttam K. Chowdhury, Dilip Lodh, Chitta R. Chanda, Anil K. Chakraborti, Gautam K. Basu. Environmental Health Perspectives, 2003, 111(9), 1194-1201.