Exposure to PCDDs/Fs: Relative Importance of The Diet and of SOn

摘要

Analysis of recent studies on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in food, soil, water, and air indicates that food, especially dairy products, meat, and fish, is the primary source of human background exposure to PCDDs/Fs. Incremental exposures ot PCDDs/Fs in soils near a sulfite pulp mill potentially affected by past deposition of flyash from power boilers were considered in the context of these background exposures. PCDDs/Fs in soil make up only a small proportion of total backgraound exposure. In areas wiht PCDDS/Fs in soils at a background concentratioin of 7.4 ng/kg, total exposure was estimated at 111 pg/day; an increase in the soil concentration to 62 ng/kg idnetified in offsite soils near the mill increased the total exposure only to 117 pg/day. These findings were included in the risk assessment fro jthe pulp mill to provide context in evaluating risk estimates related to PCDds/Fs in soil. The relative importance of background exposures to PCDDS/Fs in application of the U.S.Envirionmental protection Agency's recent soil cleanup levels of 1 mumg/kg for residential sites and 5-20 umg/kg for industrial sites is also explored.