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Risk Assessment for School Sites - Child-Specific Reference Doses (chRDs)

Child-specific reference doses (chRDs) are numerical health guidance values developed by the Office of Environmental Health Hazard Assessment (OEHHA) on behalf of the California Environmental Protection Agency, pursuant to Health and Safety Code Sections 901(f) and 901(g). ChRDs were developed in response to the increasing evidence that children are more sensitive to the effects of some toxic chemicals than adults and to address the growing concern that existing Reference Doses (RfDs) may not adequately account for this increased sensitivity. ChRDs and associated guidance is intended to assess exposure and health risk at existing and proposed school sites, including child-specific routes of exposure unique to the school environment.

As mandated by HSC 901(g), OEHHA identified seventy-eight chemical contaminants to be of greatest concern at school sites for causing adverse effects in children. Criterion was based on child-specific exposure and child-specific physiological sensitivities. This list should be viewed as a living compilation - chemicals may be added or removed as new information becomes available. As further mandated by 901(g), OEHHA will publish numerical health guidance values for five of those chemical contaminants identified annually until the contaminants identified have been exhausted. In developing the chRDs, OEHHA follows the requirements set forth in Health and Safety Code Section 57003 for receiving public input. Such values will be made available to the public, other state and local government entities, public health agencies, and school districts. Presently, numerical health guidance values have been developed for both cancer and non-cancer chemicals.

OEHHA is in the process of updating the chRDs and adopting additional health guidance values.

Additional Information

Child-Specific Reference Doses (chRDs) News

Dec 23, 2005: Final Report: Child-Specific Reference Doses (chRDs) for School Site Risk Assessment: Cadmium, Chlordane, Heptachlor, Heptachlor Epoxide, Methoxychlor, and Nickel
Release of the final technical document establishing chRDs for six chemicals to be used in school site risk assessments, including cadmium (1.1 x 10^-5 mg/kg-day), chlordane (3.3 x 10^-5 mg/kg-day), heptachlor (3.0 x 10^-5 mg/kg-day), heptachlor epoxide (1.3 x 10^-5 mg/kg-day), methoxychlor (2.0 x 10^-5 mg/kg-day), and Nickel (1.1 x 10^-2 mg/kg-day).