PREDICTION OF 1,4-DIOXANE DISPERSION BASED ON CHANGE IN GROUNDWATER FLOW AFTER REMEDIAL MEASURES BY THREE-DIMENSIONAL NUMERICAL SIMULATION - TOWARD A PERMANENT MEASURE FOR AOMORI-IWATE ILLEGAL DUMPING SITE -

Abstract

 An illegal dumping site on the prefectural boundary between Aomori and Iwate is one of the largest illegal dumping sites in Japan. Aomori and Iwate prefectures have conducted measures respectively, so there is a problem on the outflow of groundwater contaminated by 1,4-dioxane from the Iwate side to the Aomori side. However, since the recognition of both prefectures to the contaminated groundwater is different, permanent measures for the contaminated groundwater have not been considered. In the present study, the numerical simulation by three-dimensional model was conducted, and the quantity of groundwater flow from the Iwate side to the Aomori side and distribution of 1,4-dioxane around the prefectural boundary are shown. In addition, assuming that future measures in both prefectures, future groundwater flow and distribution of 1,4-dioxane were predicted. Based on the results, necessity of permanent measures for contaminated groundwater on the prefectural boundary was suggested.