Evaluation of Barriers to Prevent Lead Contamination of Produce Grown in Urban Gardens

High lead (Pb) contamination of soils is a threat to human health. Indirect ingestion occurs within the food chain through activities such as growing vegetables with an ability to accumulate lead in edible tissues. Many university extension systems recommend growing vegetables in raised beds to avoid lead contamination. However, there is limited scientific evidence of the efficacy of raised beds in reducing lead uptake in vegetable crops. To address the soil-lead exposure pathway from garden to consumption, this study supplements gaps in the literature pertaining to raised-bed garden practices by evaluating lining materials. Simulated raised beds were constructed to evaluate barriers (neoprene rubber sheeting, landscape fabric and a no barrier control) placed between contaminated (500 ppm) and uncontaminated garden media. The resulting data suggests that neoprene rubber sheeting is not an effective barrier to prevent lead uptake in vegetable crops. In fact, the neoprene barrier contained elevated amounts of lead contributing to higher levels of lead (p ≤ 0.05) within the plant tissue as compared to a no barrier treatment.