But the level of arsenic contamination in soil of ERTC, Thailand was higher than this study with the value of 380.1 mg/kg, and the difference was caused by different sampling point and different period. The duration of the data collecting has a difference of 2 years. The environment changed and flooding causes the reduction of soil arsenic contamination [20, 21]. The median of arsenic concentration both of resident water and farm water were lower than standard limit value of NEB, Thailand at 10 μg/L. It showed that farmers and household resident were safe with water consumption