Abstract

The purpose of this study was to examine an urban garden as a sample for heavy metal contamination in its soil and consumable produce. The potential public health hazards when the products were consumed were also examined. Heavy metal concentrations in the soil and the edible portion of plants grown in a major northeastern U.S. community garden were examined using the Environmental Protection Agency (EPA) 3051A method and inductively coupled plasma-mass spectrometry (ICP-MS). Concentrations of Al, Cr, Fe, Ni, Cu, Zn, As, Cd, and Pb were analyzed. Garden soil concentrations of Fe, Al, and Pb were found to be the highest (mg/kg): 8974 ± 3560, 4887 ± 534, 261.5 ± 497.6 respectively, while Ni, As, and Cd were the lowest (mg/kg): 11.6 ± 1.6, 5.6 ± 0.6, and 0.3 ± 0.0, respectively. The concentration of Al, Fe, Zn, and Pb were found to be the highest in the kale and tomato samples. The concentration of Cu in some of the kale and in all tomato samples was much higher than the standard levels for this element in plant’s dry matter (2–20 mg kg-1 dry matter). Strong positive correlations were found in soil and plant metal concentrations among the following: Cr and Ni, Zn, As, Cd, and Pb; Ni, Cu, and Zn; Cu, Zn, and Cd; and, Zn, As, and Cd. Based on published recommended upper limits (UL), consumption of 100g of the kale samples taken from the studied garden would result in the intake of an average of 0.90mg of As, four times the UL, and 6.46mg of Pb, seven times the recommended UL. Consumption of 100g of tomatoes would result in 7.1mg of Pb, or seven times the UL. These findings, when compiled with previously established linkages between heavy metal contamination and chronic illness, suggest an emerging public health risk for produce grown in certain community gardens. Soil contamination is common and poses significant health problems; therefore, more detailed studies with larger sample size are needed.