Heavy metals in urban community gardens: An analysis of risk to gardeners and the food they produce in West Philadelphia

With urban agriculture expanding rapidly nationwide, ensuring the safety of both the gardeners and the food they produce is crucial. Urban gardens build community, reclaim and beautify urban space, and help give people access to fresh, locally produced food. However, pursuit of these positive goals may entail serious health hazards for urban populations unless we explore the extent to which both urban gardeners and the food they produce may be significantly contaminated with toxic metals. Elevated heavy-metal levels in urban soils are a potential source for increased blood metal levels in residents via hand-to-mouth ingestion, skin absorption, and dust inhalation. This research investigates whether heavy metals contaminate urban community gardens in West Philadelphia. It strives to determine the risk to community members of consuming foods grown in these gardens and of coming in contact with contaminated soil. 225 samples of garden soil from 7 of the Urban Tree Connection's gardens were collected following EPA and PA DEP standards. X-Ray Fluorescence analysis was performed to determine initial total heavy-metal concentrations. Select samples will be sent to an EPA-certified lab for total sorbed-metal concentrations. Preliminary data suggest that there is a plausible threat from toxic heavy metals, specifically mercury (Hg). To assess the probable cause of observed contamination, compilations of historic records of garden locations reconstruct land-use history. Data will assist in the identification of effective garden-remediation techniques to reduce exposure to heavy metals and the recommendation to development standard procedures for the testing and construction of new urban agricultural sites.