Impact of the uncontrolled leakage of leachate from a municipal solid waste landfill on soil in a cultivated-calcareous environment

摘要

The heavy metal pollution generated by landfill leachate becomes increasingly concerning due to its potential to impact human health through the food chain. In the present study, the accumulation and potential health risk of heavy metals (Zn, Cu, Cd, Pb, and Ni) were investigated in a calcareous soil -wheat system affected by an uncontrolled landfill leachate. The results showed soils were significantly enriched by both the available and total fractions of the metals in the sequences of Zn  Pb  Ni  Cd  Cu and Cd  Zn  Ni  Pb  Cu, respectively. Nevertheless, only the Cd content exceeded the standard levels. For the various population groups, the mean hazard quotient (HQ) was lower than the unity, implying a lack of non-carcinogenic health risk for the local residents, while the average hazard index (HI) was 2.3 and 1.1 for people aged 0–5 and 6–18 years, respectively, illustrating a moderate non-carcinogenic health risk for the two groups. Cd and Pb contributed the most to HI, followed by Cu, Zn, and Ni. In addition, the carcinogenic health risk of Cd, ranging from 1 × 10−5to 1 × 10−6, showed a low potential risk in the different population groups exposed to wheat grains and decreased in the sequence of adult  population 6–18 years  population 0–5 years. The findings of the study, which can be used in regions under similar environmental conditions, provide a valuable benchmark for the design of appropriate strategies to manage these agroecosystems by both local and national managers of such macrosystems.