Arsenic Contamination in Groundwater, Soil and Rice Grain of Nepal

Arsenic (As) contamination in groundwater is a serious issue of many countries which can contaminate soil & crops growing in that area. The As contamination in water, soil & crops was evaluated from As affected district Nawalparasi (Nepal). The As level in water was above the national (0.05 mgL-1) & WHO standards (0.01 mg L-1). However, soil & rice grain samples showed As contamination in safe level. Water samples showed As concentration in the range of 0.1 mg L-1 to 1.86 mg L-1 except one sample (0.009 mg L-1). The average As concentration in pre/post monsoon season were 0.73 mg L-1 & 0.59 mg L-1. 66.67% water samples showed higher As concentration in pre-monsoon season. As concentration in all soil samples were in the range of 0.35 mg kg-1 to 9.55 mg kg-1 with average of 3.14 mg kg-1 which is below 20 mg of As kg1 in soil as the safe level in agricultural soil for crops. In rice grain samples, the average As concentration was about 0.738 mg kg-1 which is below 1.0 mg kg1 as food hygiene standard level of As. Specifically, four rice grain samples contained As level in the range of 0.35 mg kg-1 to 1.9 mg kg-1 & three samples showed below detection limit (0.005 mg kg-1).