Lead in Urban Soils: A Real or Perceived Concern for Urban Agriculture?

• Published in: Journal of environmental quality Vol. 45; no. 1; pp. 26 - 36
• Main Authors: Brown, Sally L., Chaney, Rufus L., Hettiarachchi, Ganga M.
• Format: Journal Article
• Language: English
• Published: United States The American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc 01-01-2016
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2015.07.0376

Urban agriculture is growing in cities across the United States. It has the potential to provide multiple benefits, including increased food security. Concerns about soil contamination in urban areas can be an impediment to urban agriculture. Lead is the most common contaminant in urban areas. In this paper, direct (soil ingestion via outdoor and indoor exposure) and indirect (consumption of food grown in Pb‐contaminated soils) exposure pathways are reviewed. It is highly unlikely that urban agriculture will increase incidences of elevated blood Pb for children in urban areas. This is due to the high likelihood that agriculture will improve soils in urban areas, resulting in reduced bioavailability of soil Pb and reduced fugitive dust. Plant uptake of Pb is also typically very low. The exceptions are low‐growing leafy crops where soil‐splash particle contamination is more likely and expanded hypocotyl root vegetables (e.g., carrot). However, even with higher bioaccumulation factors, it is not clear that the Pb in root vegetables or any other crops will be absorbed after eating. Studies have shown limited absorption of Pb when ingested with food. Best management practices to assure minimal potential for exposure are also common practices in urban gardens. These include the use of residuals‐based composts and soil amendments and attention to keeping soil out of homes. This review suggests that benefits associated with urban agriculture far outweigh any risks posed by elevated soil Pb.
Core Ideas
Urban agriculture offers a wide range of public health and ecosystem benefits.
Urban soil contamination is perceived to be a risk to urban agriculture.
Urban agriculture is not likely to pose any additional health risks associated with soil Pb.
Best urban farming practices are also best practices to limit any risk associated with soil Pb.