RESUMEN
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 Znâ¯>â¯Pbâ¯>â¯Niâ¯>â¯Cdâ¯>â¯Cu and Cdâ¯>â¯Znâ¯>â¯Niâ¯>â¯Pbâ¯>â¯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 6-18â¯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 1â¯×â¯10-5 to 1â¯×â¯10-6, showed a low potential risk in the different population groups exposed to wheat grains and decreased in the sequence of adultâ¯>â¯population 6-18â¯yearsâ¯>â¯population 0-5â¯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.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Adulto , China , Monitoreo del Ambiente , Humanos , Medición de Riesgo , Suelo , Residuos Sólidos , Instalaciones de Eliminación de ResiduosRESUMEN
Morphological, physicochemical, and mineralogical properties of Vertisols (Chromic Calcixererts, Typic Haploxererts, and Typic Calcixererts) influenced under farming practices and adjoining uncultivated soils were investigated in order to contribute to the understanding of changes derived by intensive cultivation (over five decades). The study revealed that A-horizon thickness enhanced from 20 cm in the uncultivated soil to 30 cm in the cultivated soil for Typic Haploxererts and Typic Calcixererts. Under cropping, calcium carbonate contents decreased (a drop of 10 to 53%) reflecting accelerated leaching and/or erosion by cultivation. For most of the studied soils, a pronounced depletion was recorded at values of soil organic carbon (23-64%), soluble cations (4-96%), and exchangeable cations (9-42%) after cropping. A considerable positive change in soil quality was observed with cultivation as recorded by a declining trend in soil electrical conductivity (a drop of 12 to 17%) and exchangeable sodium percentage (a drop of 9 to 12%). On average, the concentration of free and crystalline Fe oxides progressively increased for Chromic Calcixererts and Typic Calcixererts following intensive cultivation. Cropping operations considerably promoted the alteration of illite and chlorite minerals into expandable minerals linked with changes in soil physicochemical properties mainly the increase in cation exchange capacity. Land productivity index (LPI), evaluated based on parametric approach, suggested that Chromic Calcixererts and Typic Haploxererts highlighted a decreasing trend in LPI values (a drop of 5 to 7%) while Typic Calcixererts manifested an increasing pattern in the index (a rise of 13%) with long-term intensive cropping.