[Distribution, Accumulation Characteristics, and Risk Assessment of Heavy Metals in Vegetable Soils of Different...

To ascertain the influence of prolonged planting on the distribution and accumulation of heavy metals in protected vegetable soil, samples from typical vegetable planting areas in Shenyang were gathered to evaluate the distribution features of Cr, Ni, Cu, Zn, Cd, and Pb in such soil. The Hakanson index, heavy metal risk assessment standard, and secondary phase to primary ratio methods were employed to evaluate the ecological hazard of soil in the research area, while the human health risk model was utilized to evaluate the health of inhabitants. The findings indicated that：① The amount of heavy metals Zn, Cr, Cu, Ni, Pb, and Cd in the topsoil （0~20 cm） of protected vegetable land in the study region decreased successively, and the content of heavy metals in the topsoil increased with the extension of planting years, of which Cd, Zn, and Cu increased most obviously, with maximum increases of 219%, 189%, and 134%, respectively. ② Heavy metals Zn, Cr, Cu, Ni, and Pb were mainly in the residual state, whereas Cd was mainly in the weak acidic state, with a maximum proportion of 53%. ③ The potential ecological risk index of Cd in the topsoil of the study area was 95.77, showing a medium ecological risk； however, the comprehensive potential ecological risk of the six heavy metals was not high. ④ The HI values of the six heavy metals in the study area were less than 1 and the risk of non-carcinogenesis was negligible； however, the carcinogenic risk of heavy metals in some sampling sites should not be ignored.