Risk Assessment of Arsenic Toxicity Through Ground Water-Soil-Rice System in Maldah District, Bengal Delta Basin, India

Abstract

Arsenic (As), a toxic trace element, is of great environmental concern due to its presence in soil, water, plant, animal and human continuum. Its high toxicity and increased appearance in the biosphere have triggered public concern. The present study measured arsenic (As) concentrations in soil, groundwater and rice plant samples of five selected blocks of Maldah district, West Bengal, India. Soil, irrigation water and rice plant samples were collected from fields from the selected study areas. The results revealed the presence of As in higher concentrations than the maximum permissible limit of As in irrigation water (0.1 mg L− 1by WHO and Indian standard) in groundwater of Manikchak (0.553 ± 0.17 mg L− 1, Kaliachak III (0.528 ± 0.20 mg L− 1), Kaliachak II (0.449 ± 0.15 mg L− 1), Kaliachak I (0.207 ± 0.19 mg L− 1) The level of As in soil was also found to higher in those four blocks. The As content in rice grain and field is positively correlated with As content in irrigation water. The analysis of As of locally grown rice, showed the presence of its concentration higher than recommended safe level of As in rice by FAO/WHO (0.2 mg Kg-1) in some villages. The data of consumption of rice per day in the survey was used for the measurement of average daily dose and hazard quotient. Kaliachak III, Manikchak and Kaliachak II showed HQ greater than 1, indicating the possibility of non-carcinogenic health hazard. The study emphasized the severity of As problem in remote areas of West Bengal, India where people consume As tainted rice due to lack of awareness about the As problem and associated health issues.