Cadmium exposure and early renal effects in the children and adults living in a tungsten-molybdenum mining areas of South China.

Adverse health effects related to accumulative cadmium (Cd) exposure have aroused widespread attention from the public in China. Knowledge on the relationships between Cd exposure and early renal effects is particularly limited for children, who are more susceptible to absorbing metals than adults. A typical Cd-polluted area of South China was selected to determine the Cd exposure and related early renal effects of the general population, including children. In total, 211 children and 806 adults were enrolled in the study. The urinary levels of Cd (U-Cd), ß2-microglobulin (U-BMG), retinol binding protein (U-RBP), and N-acetyl-ß-D-glucosaminidase (U-NAG) were measured. The relationship between U-Cd and ranked indicators of early renal effects was examined by multiple regression analysis. The average U-Cd ranged from 7.01 µg/g creatinine (boys) to 13.55 µg/g creatinine (women) in the Cd-polluted areas. These values are much higher than those of the control group and those that have been reported by other countries. In agreement with previous studies, environmental Cd pollution resulted in elevated Cd accumulation in the bodies of children, and it increased the concentration of NAG in their urine. Similarly, environmental Cd pollution increased NAG and BMG in the urine of adults. Multivariate models showed that the urinary excretion of BMG, RBP, and NAG was positively associated with Cd levels in the urine of both children and adults. The reference thresholds of U-Cd in relation to elevated U-BMG, U-RBP, and U-NAG were higher in children than adults after standardization for other covariates. These results reinforce the need to control and regulate the sources of environmental Cd contamination and to promote more effective risk management measures, especially for vulnerable groups.

Fate of nitrogen in overlying water with biochar addition to sediment in planted ditches.

Best management practice (BMP) in drainage ditch systems is of high concern due to its importance in intercepting and removing pollution. Biochar has recently become an interesting option for agricultural pollution elimination, but knowledge is still limited on the fate of nitrogen (N) in drainage ditch systems with biochar added into the sediment. This isotope tracer study examined the effects of biochar addition into the sediment on the fate of inorganic N (15N-NO3- and 15N-NH4+) in sediment microcosms through a 93 day incubation experiment. Four types of sediment microcosm (sediment only, sediment + biochar, sediment + plant, sediment + biochar + plant) were set to investigate N migration and transformation using 15N pool dilution. The results indicated that 0.75% biochar addition significantly increased sediment pH and water holding capacity by 0.29 and 2.6%, respectively. Biochar addition suppressed sediment 15N-N2O emissions and decreased 15N uptake by Calamagrostis angustifolia. From the 15N distribution in different sediment layers, it was found that biochar may increase the risk of N leaching and speed up its downward mobility. Meanwhile, 15N fate was affected by the planting of Calamagrostis angustifolia, exhibiting reduced leakage and residue in sediment. Vegetated microcosms suppressed N2O emissions, as the Calamagrostis angustifolia effectively competed with microbes and utilized N for its own growth and development. Therefore, Calamagrostis angustifolia could be beneficial in the removal of agricultural non-point source nitrogen pollution as a potential option for BMP.

Bioaccumulation and sources of metal(loid)s in lilies and their potential health risks.

Dietary intake of metal(loid)s can seriously affect human health, but the levels, the bioaccumulation, sources and related health risks of As, Cd, Cr and Pb in cultivated lilies, particularly for Lilium davidii var. unicolor, remain unresolved. We collected 35 lily samples aged 1-6 years from farmlands of two types of soil (heilu soils and loessal soils) in Qilihe district in 2016 and analysed the concentrations of As, Cd, Cr and Pb in bulbs, the soil-bulb bioaccumulation and the potential sources of these elements in bulbs. Non-carcinogenic and carcinogenic risks by consuming lilies were also assessed. Concentrations of four elements decreased in the order of Cr > Pb > Cd > As, and soil-bulb BCFs in the order of BCFCd > BCFCr > BCFPb > BCFAs. The Cd concentration of bulbs of lilies which grew in heilu soils was statistically higher than that of bulbs of lilies which grew in loessal soils, and the Cd concentration of bulbs of lilies aged 1-3 years was statistically higher than that of bulbs of lilies aged 4-6 years. Levels and soil-bulb BCFs of Cr and Pb of two-bulbed lilies were statistically higher than those of one-bulbed lilies. Farmyard manure may be a primary source of Cd in soil. There existed overall potential non-carcinogenic effects by exposure to the combination of four elements. Dietary intake of Cr posed carcinogenic risks to both adults and children. Non-carcinogenic and carcinogenic risks were higher for adults than children. Concluding, the edible parts of lily were significantly polluted by Cr and Pb but not by As and Cd. The number of bulbs significantly impacted concentrations and soil-bulb BCFs of Cr and Pb, but the reason for which needs further studies. Non-carcinogenic and carcinogenic risks caused by lily consumption should not be neglected.