Soil and food plant contamination with heavy metals due to long-term wastewater irrigation, Beijing, China

摘要

Heavy metals can be gradually accumulated in the wastewater-irrigated soils, and lead to the contamination of food plants. Consumption of metal- contamlnated plants is the major food chain route for human exposure and poses health risks. In this study, results showed that the heavy metals including Cd, Cr, Cu, Ni, Pb and Zn, were significantly increased over the reference soils. Regarding the pollution load index, the results indicate that the wastewater- irrigated soils were moderately enriched with Cr, Cu, Ni, Pb and Zn, while strongly enriched with Cd. This study indicated that heavy metal concentrations in the plants grown in wastewater-irrigated soils were significantly higher (from P<0. 05 to P<0. 001) than reference soil grown plants. Heavy metal concentrations partially and/or totally exceeded the permissible limits set by State Environmental Protection Agency (SEPA) in China, and World Health Organization (WHO). Furthermore, this study highlights the potential health risks associated with the consumption of contaminated food plants. However, the values of health risk index were <1, indicating a relative absence of health risks associated with the ingestion of contaminated vegetables.