Assessing soil lead contamination at multiple scales in Oakland, California: Implications for urban agriculture and environmental justice

As urban agriculture grows in popularity throughout North America, vacant lots, underutilized parks, and other open spaces are becoming prime targets for food production. In many post-industrial landscapes and in neighborhoods with a high density of old housing stock, the risk of lead (Pb) contamination at such sites is raising concerns. This paper evaluates the extent to which soil Pb contamination may be an obstacle to the expansion of urban agriculture in Oakland, California. Using a combination of soil sampling at 112 sites, GIS, hot spot analysis, and reconstructed land use histories, the research reveals that soil Pb concentrations are generally lower than federal screening levels of 400 ppm, but significantly higher in West Oakland, the city's oldest area and home to a predominantly low-income and African American population. Lead levels are significantly lower in the affluent, predominantly white Oakland hills. Spatial analysis at city- and neighborhood-scales reveals clusters of Pb contamination related to land use history. Site-scale analyses at 12 sites reveals a high level of variability (in some cases related to land use history) that must be taken into consideration when planning for urban agriculture. (C) 2012 Elsevier Ltd. All rights reserved.