Heavy metal accumulation and health risk assessment in soil-wheat system under different nitrogen levels
2018
Zhang, Yang | Yin, Changbin | Cao, Suzhen | Cheng, Leilei | Wu, Guosheng | Guo, Jianbiao
Heavy metal(loid)s (HMs) in organic fertilizer have become a primary source of HMs pollution of farmlands, which could cause deleterious health effects in people exposed through soil-plant systems via multi-pathways. This study investigated China's main grain production area (Henan Province) to evaluate the accumulation and transport characteristics of HMs (Cr, Mn, Ni, Cu, Zn, As, Cd and Pb) in a soil-wheat system and conduct a health risk assessment for wheat (Triticum aestivum) grain under different nitrogenous fertilizer treatments. The results indicated that the Cr, Cu, As and Cd contents in soil were 56.21–113.66, 13.97–58.72, 5.79–22.62 and 0.04–0.23mg·kg⁻¹, and the mean contents of Cr and As contents in wheat grains were 0.78±0.31 and 0.49±0.18mg·kg⁻¹, respectively, which exceeded the corresponding standards. The bio-concentration factor and transfer factor were lowest in response to N-fertilization with N8–N15. Health risk assessment showed that the local population who ingested grain from culture condition of N15 experienced the lowest non-cancer and cancer risks. Among different population groups, HMs posed relatively higher non-cancer and cancer risks to children aged 0–5years. Furthermore, Cr and As exposure was the greatest contributor to Hazard Index (HI), accounting for 74.72–83.11%, while Cr exposure accounted for >90% of the total potential cancer risk. Concluding, this study indicated that, to protect human health, the current application of nitrogenous fertilizer should be controlled to an appropriate level.
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