- WEB EXCLUSIVE
- PE COFFEEHAUS
Currently, federally recommended dioxin PRGs are 1,000 part per trillion (ppt) for dioxin in residential soil and a level within the range of 5,000 to 20,000 ppt in commercial/industrial soil. The draft interim PRGs proposed are 72 ppt for residential land uses and 950 ppt for commercial/industrial land uses, thus lowering the amount of dioxins levels for residential land uses and commercial/industrial land uses.
The draft interim PRGs also differ from the current dioxin PRGs in that they include consideration of the potential absorption of dioxin through skin exposure. This will provide a tool for site evaluation that was not available when EPA last recommended PRGs for dioxins in soil in 1998, the agency said.
In 1991, in light of significant new data on the potential human health effects of dioxins, the EPA began the development of a comprehensive evaluation of exposure and human health effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the group of chemicals known as dioxins, and other dioxin-like compounds. This draft dioxins assessment has been through several independent external peer reviews, the latest a 2004 review by a scientific panel convened by the National Academy of Sciences. When the EPA dioxin risk assessment is complete, it will be the agency's scientific foundation for future decision-making about dioxins in the environment, the agency noted.
The EPA will be taking public comment on the draft interim PRGs through Feb. 22, 2010, and anticipates issuing the final interim PRGs in June 2010. Upon completion of the dioxins reassessment, currently expected by the end of 2010, the agency will consider the need to update the interim PRGs.