Study on Arsenic Mobility through Groundwater Irrigation in a Part of Chakdah Block, Nadia District, West Bengal

Abstract

Like the revolution of the earth round the sun, the God-gifted natural freshwater resource is supposed to be used by the human beings for drinking as well as irrigation purpose. This vital resource makes up 60 percent of the human body. But groundwater has been losing its potability not only due to various anthropogenic activities but also its huge development in irrigation sector. In recent-past, Arsenic (As) exposure in human beings from groundwater has been reported and millions of people have been suffering from arsenicosis both in many parts of developing and developed countries.

India is a land of agriculture including West Bengal. Agriculture is the main occupation of the villagers in West Bengal and large source of economy. However the cultivation is mostly seasonal and generally depends on grace of nature. The high As groundwater is an important issue in rural Bengal, where due to insufficient rainwater in pre-monsoon season, the local farmers are being compelled to execute by withdrawing groundwater by installing irrigation wells. Hence large-scale groundwater development for irrigation purposes has been practiced to aid in the summer crops production in West Bengal.

The present study involves the monitoring of As mobilization through irrigation groundwater in a selected area-of-interest in Chakdah block of Nadia district, West Bengal. Chemical quality parameters of groundwater have been determined through testing of collected groundwater samples during pre-monsoon season. It has been found that the As concentration of the maximum irrigation wells are relatively high exceeding the WHO's recommended safe limit (i.e. 10μg/L of As), indicating the possible chances of As migration through crops and food chain.

Surface driven fresh organic matter may have some important role in mobilizing As in groundwater. In this context, the role of iron mineralogy and anoxic environment in the shallow aquifer zone are also important factors. Therefore, groundwater irrigation beneficiary communities in this area should aware about mobility of As in groundwater for their agri-food security.