Arsenic Contamination in Groundwater of Nawalpur District

Arsenic is a chemical element that is widely distributed throughout the environment in the air, water, and earth’s crust. It is a confirmed carcinogen and highly toxic in its inorganic form. Groundwater is the primary source of water for drinking, irrigation, sanitation, feeding livestock, and industrial purposes in the Terai region of Nepal. Multiple studies have shown that the groundwater has been contaminated with arsenic (As) in districts such as Siraha, Dhanusha, Rautahat, Bara, Nawalpur, and Rupandehi. The effects of As contamination range from human health issues such as arsenic poisoning, skin diseases, and cancer to soil and crop contamination. Thus, groundwater contaminated with arsenic (As) has been a severe water issue for people residing in these districts. This study encompasses the determination of arsenic contamination in groundwater over different administrative wards of Gaindakot Municipality in the Nawalpur District. A limited number of 52 initial samples were pretested using the Hack As-Test kit on-site, which used mercuric bromide-coated film as a tester agent, while detailed analytical analysis was conducted using atomic absorption spectroscopy (AAS) and a UV-Vis spectrophotometer. Among the 52 samples tested, 7.69% had arsenic concentrations in groundwater above standard levels (National standards: 0.05 mg/L and WHO standards: 0.01 mg/L). Arsenic detected in the groundwater samples was of geogenic origin, as confirmed by various past research studies. The Arsenic Biosand Filter (ABF), made from locally available materials that proved to be up to 96% efficient in removing arsenic, was recommended to be installed in drinking water supplies at each administrative ward and in public places such as schools, parks, and hospitals around the municipality.