Groundwater arsenic contamination and associated health risks in Bihar, India

The extent of groundwater arsenic (As) contamination and associated health-risks were studied in the four villages: Chaukia and Terahrasiya (Vaishali); Mamalkha and Masharu (Bhagalpur) in Bihar, India. Groundwater samples were tested using the standard Silverdiethyledithiocarbamate method at 520nm by Thermo UV-1 spectrophotometer. The As levels in both the districts exceeded the WHO standard of 10μg/L for drinking water with a maximum value of 20μg/L in Vaishali and 143μg/L in Bhagalpur. However, the FAO standard of 100μg/L of As for irrigation water was only exceeded in Bhagalpur. The calculated range of the hazard index (HI) for Vaishali was 0.9 to 10, and for Bhagalpur was 10.40 to 40.47. Both ranges exceed the accepted normal toxic HI of 1.00. The cancer risk was derived as 1-5/1000 people to 5-16/10,000 people in Vaishali, and 7-21/1000 and 5-16/1000 people in Bhagalpur. Prevalence of skin pigmentation was double in Vaishali in comparison to Bhagalpur. The analysis of principal components showed that only two components had a fundamental role in defining variance for cancer risk assessment. A more extensive screening of As contamination of groundwater and a follow-up clinical study are necessary to accurately assess the likelihood of As-related cancers in these districts.