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Pollution resulting from toxic trace elements is an increasing concern around the world especially in developing countries such as China. Rapid industrialisation, urbanisation and agricultural development are the dominant sources of anthropogenic contamination contributed to an increased potential toxicity of trace elements in the irrigation water–soil–food chain. Xin Jiang in China is a reserved cultivated land development area that could provide the most extensive strategic support for food production and arable land security in China. Thus, it is crucial to investigate the bioaccumulation and translocation of trace elements in order to assess the ecological and human health risks in the traditional oasis system of the agricultural areas in Bay Cheng County, Xin Jiang. This study analysed the levels of trace elements in different layers of the soil, the irrigation water and the wheat plants, and the relationships among them. The results indicated that cadmium (Cd) and chromium (Cr) were the primary pollutants in soils and wheats respectively, and they fell into the serious pollution category. However, no trace elements over the pollution limits were detected in irrigation water. The maximum values of trace elements appeared in the soil layers at 5–10 cm and 10–15 cm. The pollution levels of trace elements in the soil layers were found at 0–5 cm and 0–20 cm, which were higher than those at 20–80 cm. In wheat, high amounts of absorption for Se, Cr, Zn and Cu, but low for Pb were detected in different parts of a plant. The roots of wheats were more eco-toxic to Cd, Co and Pb than other tissues, indicating that roots were more effective at absorbing Cd, Co and Pb, as these metals are usually toxic in the soil. Se, Cu and Zn showed a higher ability of being transferred from soils to the edible parts of crops. The bio-transfer factors of Zn, Mo, Cu, Mg and Mn were considerably higher than those of other elements. The average cancer risk of As, Cd, Co, Ni and TCR in wheat grains exceeded the safety reference limit (1 × 10−4). For the exposed population, Cr in wheat was the major contributor to total cancer risk. The average values of HQ of Cr, Mn and As, and total non-cancer risk index exceeded the corresponding effective safe reference doses (HQ > 1). [ABSTRACT FROM AUTHOR]

Purpose: Trace element pollution in soil has become an increasingly common issue and potentially harms the environment and human health. In this study, the contamination levels and ecological and health risk indices of trace elements in surface soils in Bai Cheng, Xin Jiang, were investigated in order to examine if the land usage changed from pasture to agriculture has influenced the behaviours of these trace elements. Material and methods: In this study, descriptive analysis, normality test, the Tukey-HSD method and non-parametric methods were used to investigate the characteristics of trace elements. The geo-accumulation pollution and ecological risk indices were used to analyse the degree of contamination by trace elements. Correlation and principle analyses were used to identify the sources of trace elements and a health risk assessment was used to analyse human exposure to trace elements of the soil. Results and discussion: Cadmium was the main pollutant in the 0–5 cm soil layer in both agricultural and pastoral areas. Thus, it contributed most to the Geo-Accumulation Index (Igeo) and the comprehensive potential ecological risk index (RI) of the surface soils. The levels of RI for the topsoil layer of agricultural areas fell into moderate to high (II-III) ecological risk categories, and those of pastoral areas belonged to low to moderate risk categories (I-II). Both values of Igeo and RI of the surface soils in agricultural areas were higher than in pastoral areas. The carcinogenic risk of Cr through hand-to-mouth intake and the total risk of trace elements in soils for humans were higher than the safety reference level. Chromium was the greatest contributor to total carcinogenic risk. Conclusions: Trace element concentration levels in surface soils in pastoral areas were relevant to geochemical characteristics and atmospheric deposition, whereas trace element concentration levels in surface soils in agricultural areas were derived not only from geochemical characteristics but also from human activities. The change in land use from pasture to agriculture increased the trace element concentration level in surface soils. There were both ecological risks and human health implications for residents exposed to such contaminants of soils in the studied region. [ABSTRACT FROM AUTHOR]

Water quality is closely associated with human health and socio-economic sustainable development. With the increasingly intensive anthropogenic activities, pollutants especially trace elements, enter water aquatic system and cause harm to humans. This study conducted the first systematic comparison on the pollution status of surface water and groundwater in China. Water quality and health risk assessment of 12 trace elements were evaluated according to the water quality index (WQI), hazard quotient (HQ), hazard index (HI), and carcinogenic risk (CR). The results showed that the average values of trace elements in the majority of surface water were higher than those in groundwater. The WQI values demonstrated that 86.02% of surface water and 83.11% of groundwater were suitable for drinking water. Arsenic served as the predominant pollutant and contributed significantly to cause the non‑carcinogenic risk on human health in both surface water and groundwater, children were more vulnerable to the adverse effects than adults. In surface water, the priority non-carcinogenic risk sites were mainly distributed in Anning River, Taizi River, Middle reaches of Huai River and Jilin section of Songhua River. For groundwater, the high-risk sites were located in Huhhot Basin, Kuitun, Jianghan Plain, Datong Basin and Yucheng County. Arsenic posed potential carcinogenic risk to local resident in some water sites, and it presented higher in groundwater than surface water. More concerns should be paid on Songhua, Yangtze and Huai River Basins, in addition, Pearl, Southeast Coastal, Southwest and Northwest River Basins still need attention. The future work should be carried out more extensive range of the water sites and long-term monitoring in China. In particular, more attention should be dedicated to assess high As water bodies. [Display omitted] • The WQI values manifested that 86.02% of surface water and 83.11% of groundwater were suitable for drinking water. • Children were more vulnerable to the adverse effects of trace elements than adults when exposed fromthe same water medium. • Arsenic contributed significantly to cause the non‑carcinogenic risk on human health in both surface water and groundwater, and it presented higher carcinogenic risk in groundwater than surface water. • More concerns should be paid on Songhua, Yangtze and Huai River Basins. [ABSTRACT FROM AUTHOR]