Levels of CDDs, CDFs, PCBs and Hg in Rural Soils of US (Project Overview)

The purpose of this study is to develop a protocol for soil sample collection, to collect samples from a number of background sites and to make initial estimates of background levels of CDD's, CDF's, PCB's and Hg in soils. This pilot survey will focus on characterizing dioxin soil levels in background areas as represented by the 31 NDAMN air sampling stations. These stations are located in rural/remote areas and represent many of the important agricultural areas of the US.

Project Status

The Work Assignment for this project was approved in April 2003. The project plan features use of a sampling strategy that uses bioassay techniques to measure total TEQs in individual samples and GCMS procedures to measure individual congeners in composite samples. A draft sampling protocol was received in May 2003.

Project Start Date


Project Completion Date (Actual/Projected)



No systematic survey of dioxins in soil has been conducted in the US. Soils represent the largest reservoir source of dioxins. As point source emissions are reduced emissions from soils become increasingly important. Understanding the distribution of dioxin levels in soils is a critical first step for determining how this source may contribute to food contamination and human exposure. In addition, EPA regulatory programs are interested in knowing background dioxin levels in soil to help with risk management decisions on dioxin cleanups and disposal practices.

Samples collected and analyzed in 2003, report drafted an internal review completed in 2004. External peer review completed in 2005. Final report was issued in April 2007.