Managing urban garden soils: Minimize potential for soil contaminant transfer
The United States General Accounting Office estimates that there are approximately 450,000 brownfield sites in the U.S. The reuse of these sites increasingly includes reuse as gardens/farms, especially in areas with food insecurities, as this provides access to nutritious food for low income populations. Yet the negative health effects of growing in potentially contaminated soils are often not known and/or addressed. The goal of this research is to increase in scientific knowledge regarding bioavailability of soil contaminants and associated best management practices; enhance the capabilities of garden/farming initiatives to produce crops locally without potentially adverse health effects to the grower or the end consumer. This presentation will highlight Kansas State University research data on growing food crops on urban gardens established on former brownfields. Challenges of converting brownfields to community gardening sites will be discussed using urban community garden sites located in Kansas City, KS, Indianapolis, IN, and Tacoma, WA as examples. These sites had elevated levels of common urban soil contaminants such as lead (Pb), arsenic (As), and/or polycyclic aromatic hydrocarbons (PAHs). Suitable safety/corrective measures were suggested and implemented after thorough evaluation of soil properties. Measures focused on improving soil quality as well as reducing both direct (soil-human) and indirect (soil-plant-human) potential transfer of contaminants to the gardeners and their children were evaluated.
Our research indicates that gardening at contaminated urban soils carries a low risk of transferring contaminants to humans via soil ingestion and vegetable consumptions. However, precautions need to be taken to minimize the direct exposure of humans to contaminated soils as it is the potential exposure pathway of concern.