Urban Farming: Lead Problems and Remediation Solutions

The increasing popularity of urban agriculture as a method of localizing food systems has created a mounting need to address soil pollution in urban farms. Lead is an especially pervasive pollutant in urban soils with a number of detrimental health effects. Phytoremediation, the use of plants to extract or degrade pollutants, has shown promise for cleaning up leadcontaminated soils, yet its potential for urban farms has not been evaluated. A meta-analysis of the literature was conducted to determine what dangers lead presents to those involved in urban farms, what food crops should not be grown when lead is present, and how a phytoremediation project designed to remove lead should be conducted. This analysis was then applied to the case study of Alemany Farm in San Francisco, CA, a farm with known lead concentrations between 60 and 720 ppm. It was found that all food crops besides tree fruits may pose a threat to human health if grown in Alemany Farm soils. A reasonable plan for phytoremediation of lead utilizing Indian mustard (Brassica juncea (L.) Czern) was found to exceed the budget available to Alemany Farm, with the time scale of the project also making it unfeasible. From the results of this study, it appears that phytoremediation will generally not be feasible for small-scale urban farms, and that other steps should be taken to reduce the threat of lead for urban farmers. Evan Green Lead Problems for Urban Farms May 12 2008