E8-24420. Availability of an Update to the ATSDR Policy Guideline for Dioxins and Dioxin-Like Compounds in Residential Soil

AGENCY:

Agency for Toxic Substances and Disease Registry (ATSDR), Department of Health and Human Services (DHHS).

ACTION:

Notice of availability.

SUMMARY:

This notice announces the availability of an Update to the ATSDR Policy Guideline for Dioxins and Dioxin-Like Compounds in Residential Soil at: http://www.atsdr.cdc.gov/​toxpro2.html and http://www.atsdr.cdc.gov/​substances/​dioxin/​policy.

DATES:

The policy update will be available on or about September 30, 2008.

ADDRESSES:

The document will be available on ATSDR's Web site at http://www.atsdr.cdc.gov/​toxpro2.html as Appendix B of the Toxicological Profile for Chlorinated Dibenzo-p-Dioxins and http://www.atsdr.cdc.gov/​substances/​dioxin/​policy.

FOR FURTHER INFORMATION CONTACT:

Dr. Tom Sinks, Office of the Director, Agency for Toxic Substances and Disease Registry, Mailstop F-61, 1600 Clifton Road, NE., Atlanta, Georgia 30333, telephone [phone].

SUPPLEMENTARY INFORMATION:

This update replaces Appendix B in the Toxicological Profile for Chlorinated Dibenzo-p-dioxins (CDDs) (December, 1998). It also supersedes ATSDR's releases of the former policy as contained in the following publications: De Rosa CT et al. 1997; J Clean Technol Environ Toxicol & Occup Med 6(2):117-163, and De Rosa CT et al. 1999; Toxicol Ind Health 15(6):552-576.

The purpose of this update is to ensure that ATSDR health assessors evaluate dioxin levels that exceed the ATSDR established screening level of 0.05 ppb as described in the ATSDR Public Health Assessment Guidance Manual (PHAGM) (ATSDR 2005). When following the PHAGM, assessors should use the 0.05 ppb value as the comparison value. The comparison value is not, however, a threshold for toxicity and should not be used to predict adverse health effects (ATSDR 2005).

This update does not signal a change in ATSDR's scientific assessment on dioxin toxicity or a change in the ATSDR Minimal Risk Level (MRL). Moreover, the update does not change the assessment of risk associated with dioxin soil levels up to 1 ppb—the level U.S. EPA has set as a preliminary remediation goal for residential soils (EPA 1998).

Dated: October 9, 2008.

Ken Rose,

Director, Office of Policy, Planning, and Evaluation, National Center for Environmental Health/Agency for Toxic Substances and Disease Registry.