Groundwater contamination by organoarsenic compounds in Kamisu City, Ibaraki Prefecture

Abstract

Groundwater contamination by organoarsenic compounds in Kamisu City, Ibaraki Prefecture was examined based on the findings of field investigations. The field investigations revealed that the primary contaminant, diphenylarsinic acid (DPAA), was mainly detected in the deep layer of the aquifer in the study area. However, the subsequent discovery of buried, concrete-like blocks just below the ground surface 90 m southeast of the well where the contamination was first detected, revealed that the blocks had remarkably higher DPAA concentrations than was observed deep within the aquifer. These blocks were thought to the most probable source of the well contamination. Moreover, the groundwater contamination has spread about 3 km downstream from the contaminant source.