Monitoring of 1,4-Dioxane in Groundwater and River Water at the Tama District in Tokyo

The monitoring of 1,4-dioxane in groundwater and river water was conducted by solid-phase extraction and GC/MS determination. 1,4-Dioxane in groundwater was investigated at 338 wells of the Tama district in Tokyo and was detected in 74.1% of shallow wells and 79.3% of deep wells. The concentrations detected ranged from 0.05 to 113μg·l-1, and the averages were 2.23μg·l-1 (shallow wells) and 4.69μg·l-1 (deep wells). The 1,4-dioxane concentration in the groundwater containing more than 50 μg·l-1 of 1,4-dioxane negligibly changed in more than 6 months. In the case of the Tama River water, 1,4-dioxane was detected at concentrations from 0.06 to 2.15 μg·l-1 at downstream sites, but was not detected at upstream site. This could be due to the inflow of effluent from sewage plants. The amount of 1,4-dioxane loaded from sewage plants ranged from 28 to 269 g·day-1.