Accumulation characteristics and evaluation of heavy metals in soils and vegetables of plastic-covered sheds in typical red soil areas of China

Abstract

The degree of pollution and potential ecological risk of heavy metals (HMs) in the soil of plastic-covered sheds in Jiangxi Province were evaluated by the Nemerow index and potential ecological risk index. The bioconcentration factor and total target hazard quotient (TTHQ) were used to evaluate the enrichment ability and health risk of HMs in vegetables. The mean contents of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg) and lead (Pb) in soil were 5.99, 0.373, 17.8, 5.94E-02, and 28.9 mg kg–1, respectively; Cd exceeded the background value and the maximum limit. Most soils had no extremely strong ecological risk. The concentration of Pb in root vegetables was 0.204 mg kg-1, with the highest concentration of Cd (0.147 mg kg–1) in Ganzhou leafy vegetables. The Hg concentration of leafy vegetables in Jiujiang was 1.41E-02 mg kg–1, which exceeded the maximum limit. The bioconcentration factor of HMs was negatively correlated with pH (P ≤ 0.05). The migration ability of Cd in root vegetables was 1.7-fold to that of leafy vegetables, and was strongest. The TTHQ of all vegetables was less than 1.0, which indicated that there was no significant noncarcinogenic risk in adults. The TTHQ of root vegetables was highest, with Pb in vegetables being major health risk factors. In conclusion, fruit and solanaceous vegetables may be more suitable for planting in plastic-covered shed than root and leafy vegetables; Cd and Pb were identified as the priority control metals under plastic-covered sheds in Jiangxi Province.