San Francisco’s Department of Public Health (SFDPH) provides guidance and regulates potential lead hazards within the city. In June 2011 SFDPH released "Lead Hazard Risk Assessment and Management Guidance for Urban Gardens and Farms" for use by San Francisco residents, community groups and City agencies. The purpose of the guidance is to address potential lead hazards and reduce risk to those engaged with local food production and reduce the potential for lead uptake by edible plants and fruit-bearing trees. Additional gardening information provided by SFDPH's Childhood Lead Prevention Program can be found here.
For comprehensive lead risk assessment SFDPH advises site assessment through both visual observation of the site and research on historic use of the garden and surrounding areas and then bulk soil sampling with precautionary hazardous risk assessment. DPH strongly recommends mitigation of any soil lead level found to be 80 parts per million (ppm) or higher. This threshold, which is much lower than the EPA guideline, is a health based threshold that represents a potential serious hazard to children as there is a detectable change in a child’s blood level at this concentration. Send soil samples to an EPA-recognized laboratory from the National Lead Laboratory Accreditation Program (NLLAP) list. Garden planners should implement lead hazard mitigation and exposure controls prior to engagement in food production activities.
The US Environmental Protection Agency (EPA) and California Department of Public Health (CDPH) regulate 400 ppm or greater of lead in bare soil as their definition of a lead in soil hazard. The CalEPA State Water Resources Control Board (SWRCB) uses 200 ppm or greater of lead for their definition of clearance prior to land use development. Neither of those values is based on the prevention of significant health effects to children.
SFDPH’s role is to investigate complaints about toxicity and hazards in soil. Per regulations set by the US EPA and CDPH, SFDPH enforces to a legal standard of 400 ppm of lead in soil and, at this level or higher, remediation may be required.
For more information on SFDPH’s role and guidelines, contact Karen Cohn (Karen.Cohn@sfdph.org or 415-252-3898) or Joe Walseth (Joe.Walseth@sfdph.org or 415-252-3956) of the Children’s Environmental Health Promotion division.
Photo: Susy Morris, ChiotsRun.com