Ashok Kumar Ghosh

Ashok Kumar Ghosh

Department of Environment and Water Management, A.N. College, Patna, Bihar, India

Increasing global temperature has caused widespread glacier recessions in the new fold mountain belts of the Himalayas. Glacial recession has affected the flow of the Ganga river system, its impact being enhanced by human interventions. There are many adverse impact of the current climate change on the drainage pattern and river ecology of the Ganga system in Bihar (India). A rapid shift in the river meander occurred along Patna within a span of a few years. The reduced volumes of river water are leading to ecological disaster in Bihar in the form of truncated channel flows, and increasing sedimentation. This, along with pollution load, has aggravated aquatic life, as revealed in large-scale herniation in the zooplanktons. Also, abrupt drop in the river depth was indicative of local faults along the river bed, implying seismic impacts of ongoing changes in the river’s regime. Our studies have concluded that climate change, apart from affecting life forms, was also altering the geomorphology of the Ganga Basin in the state of Bihar.

The northern part of the state of Bihar, India, has innumerable south flowing streams that are subject to annual inundation. The river basins bear numerous water bodies and marshy lands. A systematic study of wetlands of north Bihar was undertaken by our research group for the period 1984 –2004 through remote sensing data. The observations are very interesting and alarming. Rapid changes in surface water regime have been detected. There is a contradictory trend in eastern and western parts of the study area, the former showing expansion of surface water and the latter revealing rapid shrinkage of the same.

Testing of groundwater used for drinking for arsenic has been undertaken more widely by our research group in several districts of Bihar with the support of UNICEF. Available data for sixteen districts are collated which provides the most up-to-date picture of areas known to be affected by arsenic in groundwater in the Indian portion of the Ganges-Brahmaputra river basin. Bihar is one of the states where the ground water is heavily contaminated with arsenic. In Bihar, on the River Ganges upstream of West Bengal, 66,623 sources from 11 districts have been tested and water samples from 10.8% of sources were found to contain arsenic at concentrations greater than 50 µgL-1 and 28.9% at concentrations greater than 10 µgL-1. 3 EastChamparanSitamarhiMadhubaniSupaulArariaKishanganjPurniaKatiharDarbhangaMuzaffarpurSheoharSaran

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There is a proven correlation between high iron and high arsenic concentrations. In Bihar, majority of the arsenic hotspots found to be distributed in HCO3 – dominated ground water facies. Contrary to our preliminary assessment that arsenic hotspots clustered along the banks of the master stream, Ganga, the interfluvial terrain and Himalayan foothills in north Bihar also tested positive for arsenic contaminated ground waters, the latest concentrations being detected in Darbahanga - Purnea Belt and the Kishanganj - Supaul Terai belts. Hence, arsenic contaminations occur continuously from the northern foothills to the south Ganga Plains, with the typical spatial variations in contamination levels within short distances. General arsenic concentrations also recorded to be decreasing with increasing depth, with the sole exception of western Bhojpur district where shallow aquifers had less arsenic levels than the progressively deeper ones. Highest concentration of 1861 μgL−1 was recorded in this district, where out of 5420 hand pumps surveyed, 45% hand pumps had more than 10 μgL−1 arsenic. In Bhagalpur district 4516 hand pumps were surveyed, out of which 24.78 % had more than 10 μgL−1 arsenic. A large number of biological samples tested positive for arsenic toxicity. The study is still going on in several districts and the complete picture is yet to emerge in some areas. Deep groundwater in particular requires a comprehensive programme of supporting research to determine appropriate aquifers and ensure aquifers tapped remain safe from arsenic in the longer term. In this and other respects continued monitoring of groundwater quality in arsenic-affected areas is of the utmost priority.

Fluoride contamination is another serious problem related to ground water of Bihar. Isolated pockets of intense fluoride contaminations have been found in the southern districts of Nawada [maximum 15.6 ppm], Gaya, Rohtas, and Munger and southern Bhagalpur district. Study of fluoride contaminations are in progress, the identified areas having aquifers at fluctuating levels and limited surface water resources in contrast to the northern water surplus districts. Villages with fluoride contaminations include Bhoopnagar and Masuribarof Amas Block, and, Bhaktauri, Kamalpur and Dhaneta of Bankebazar Block [Gaya District]; Rajauli, Kachariyadih and Muslim Tola [Nawada District].

All the studies undertaken by our research group related to water quality and quantity indicate that the state of Bihar is going to face serious water scarcity in near future. Water crisis will become endemic in this water surplus state and urgent remedial measures are required to preserve and protect this precious water resource essential for our survival.

References
[1] Ghosh et al., (2007) Global Warming and changing land use patterns in Bihar Plains, India. In: Proceedings of Annual Conference of Royal Geographical Society, London.

[2] Ghosh et al., (2004) The Impact of Changing Surface Water Configuration on Land use of Bihar, India. In: Proceedings of ISCO 2004 Conference, Brisbane, Australia.

[3] Nickson et al., (2007). Current knowledge on the distribution of arsenic in groundwater in five states of India. Journal of Environmental Science and Health, 42: 1–12.

[4] Ghosh, A., N. Bose, A.G. Bhatt and R. Kumar (2010) New dimensions of groundwater arsenic Contamination in Mid-Ganga Plain, India. Arsenic in Geosphere and Human Dimensions-As 2010 CRC Press, UK.

[5] Ghosh, A., S.K. Singh and N. Bose (2009) Monitoring and Management of Arsenic and Fluoride Contamination in Ground Water of Bihar [India]. In: Bangladesh Chemical Congress, University of Dhaka, Bangladesh, pp15-16

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