Groundwater Arsenic Contamination in India: Vulnerability and Scope for Remedy

Arsenic contamination in groundwater in the GangaBrahmaputra fluvial plains in India and Padma-Meghna fluvial plains in Bangladesh and its consequences to the human health have been reported as one of the world’s biggest natural groundwater calamities to the mankind. In India, seven states namelyWest Bengal, Jharkhand, Bihar, Uttar Pradesh in the flood plain of the Ganga River; Assam and Manipur in the flood plain of the Brahamaputra and Imphal rivers and Rajnandgaon village in Chhattisgarh state have so far been reported affected by Arsenic contamination in groundwater above the permissible limit of 10 μg/L. People in these affected states have chronically been exposed to drinking Arsenic contaminated hand tube-wells water. With every new survey, more Arsenic affected villages and people suffering from Arsenic related diseases are being reported, and the issues are getting complicated by a number of unknown factors. These fluvial plains represent Holocene aquifers of recent alluvial sediments and have the routes originated from the Himalayan region. Arsenic groundwater contamination has farreaching consequences including its ingestion through food chain which are in the form of social disorders, health hazards and socio-economic dissolution besides its sprawling with movement, and exploitation of groundwater. Arsenic contamination is understood to be of geogenic origin released from soil under conditions conducive to dissolution of Arsenic from solid phase on soil grains to liquid phase in water, and percolation of fertilizer residues might have played a modifying role in its further exaggeration. There are a number of hypotheses about the source of Arsenic and probable reasons of occurrence in groundwater. Over the last 25 years since the groundwater Arsenic contamination was first surfaced in the year 1983, a number of restorative and precautionary measures coupled with action plans focusing mainly on detailed investigations to understand the physiochemical process and mechanism, alternate arrangement to supply Arsenic free water to the affected populace and development of devices for Arsenic removal and their implementation at the field, etc. have been initiated mainly in West Bengal while in other States, they are meager. Despite a number of corrective and precautionary measures, the spread of Arsenic contamination in groundwater continued to grow and more new areas were added to the list of contaminated area. The problem resolving issues, thus, seemed to be partial and inadequate, which need to be strengthened by strategic scientific backing. Numerous investigators have come out with a number of findings, and alternatives propositions, which varied from identification of shortfalls to success stories. The present state of affairs of the Arsenic menace in India demand a systematic translation of success stories of one place/region to another, and overcoming the shortfalls by conceiving R&D studies in areas wherever deemed fit. Advancement in understanding of geochemical and mobilization processes, devising satisfactory Arsenic removal filters, identification of shortfalls in operation and maintenance of Arsenic removal techniques, delineation of risk free deeper aquifers as an alternate source of groundwater, developing surface water based water supply schemes in many Arsenic affected areas, success stories of community participation in running Arsenic removal plants, etc. are some of the important achievements, which could help derive a comprehensive framework of activities leading to mitigation and remediation of the issues emerging out of Arsenic menace. The paper is thus aimed at highlighting the state-of-affairs of Arsenic groundwater contamination in India along with narration of various corrective and precautionary measures taken up so far