Evaluation Report for School Site Risk Assessment: Dieldrin

The Office of Environmental Health Hazard Assessment (OEHHA) is required under Health and Safety Code Section 901(g) (Section) to identify those chemical contaminants commonly found at school sites and determined by OEHHA to be of greatest concern based on child-specific physiological sensitivities.  The Section also requires OEHHA to evaluate and publish, as appropriate, numerical health guidance values, such as child-specific reference doses (chRDs), for these chemical contaminants.

OEHHA has identified dieldrin as a contaminant of concern pursuant to the Section. In an updated review of available literature, OEHHA has found additional information that exposure to dieldrin during the childhood neurological developmental period could irreversibly impact the system of nerve cells that use dopamine as its neurotransmitter.  Progressive adverse effects on the nigrostriatal dopamine system from early-life exposure might contribute to an early onset of Parkinson's disease.  While this developmental neurotoxicity may be a very sensitive endpoint, available data do not permit a determination of the lowest dose for this effect.  Accordingly, OEHHA is not proposing a chRD for dieldrin.  Instead, OEHHA recommends the use of the U.S. Environmental Protection Agency’s reference dose, or the Agency for Toxic Substances and Disease Registry’s minimal risk level, both of which have a value of 5x10-5mg/kg-day, in assessing the non-cancer risk of dieldrin at school sites.  This chronic reference dose is based on liver toxicity of dieldrin.

The document is considered a status report on dieldrin’s potential to impact children at very low doses.  Because this evaluation did not lead to a new quantitative assessment of dieldrin’s toxicity, it did not undergo external peer review or public review.  Should new information be obtained that leads to a quantitative risk assessment of the chemical, that assessment will undergo the necessary and required reviews before being released.

This report is available to the public via the OEHHA Web site.

If you have any questions, please contact Carmen Milanes at (916) 323-4153, E-mail at carmen.milanes@oehha.ca.gov, or by mail at:

Office of Environmental Health Hazard Assessment
PO Box 4010, MS-12B
Sacramento, CA 95812-4010

FAX: (916) 322-9705