The Concentrations, Sources, Ecological, and Human Health Risk Assessment of Heavy Metals in Roadside Soils of Six Cities in Shanxi Province, China.

Roadside soils are regarded as a reservoir for heavy metal pollution, which potentially leads to ecosystem deterioration as well as serious hazard to human health. A comprehensive investigation was conducted for the levels, relationship with soil properties, and potential sources of heavy metals (Hg, Cu, Zn, Pb, Cd, and Cr) in roadside soils in six cities (Changzhi, Jincheng, Yuncheng, Linfen, Xinzhou, Datong) of Shanxi Province; and the corresponding ecological risk and human health risk associated with the concentrations of heavy metals were addressed. Heavy metal concentrations of 112 roadside soil samples in the surveyed cities were, in decreasing order, Zn, Cu, Cr, Pb, Cd, and Hg, which were higher than corresponding background values. The highest concentrations were in Changzhi. The results of Pearson correlation analysis demonstrated that positive correlations in varying degrees existed between soil properties such as electrical conductivity, total nitrogen, total phosphorus, and total organic carbon with specific heavy metals and that negative correlations were observed for clay and electrical conductivity. Anthropogenic sources related to traffic emissions and industrialization were the main sources of heavy metals in roadside soils according to principal component analysis. The ecological risk assessments were achieved by pollution index and potential risk index, indicating that contamination with Hg was the most serious, which posed the highest risk to the ecosystems in the surveyed cities; and the ecological risk in Changzhi ranked at the top compared with other cities. For the human health risk assessment, the results demonstrated that the noncarcinogenic and carcinogenic risks were in the acceptable range in the surveyed cities. However, there was a higher health risk from heavy metal exposure for children than adults, and the main exposure pathway was soil ingestion. In addition, Changzhi was the city with the highest noncarcinogenic and carcinogenic risks, and the main human health risks were posed by Cr contamination in roadside soil, which was different from the results of ecological risks. Both results of ecological and health risk assessment demonstrated that the higher risk exhibited in southern and southeastern cities than northern cities in Shanxi Province. Environ Toxicol Chem 2023;42:1485-1500. © 2023 SETAC.

[Scale-dependency of spatial variability of surface soil moisture under different land use types in Heihe Oasis, China].

To study the surface soil moisture spatial variability and its scale effect is of significance to understand the real variability of soil moisture and to objectively provide a reference for constructing a logical sampling scheme. By using "re-sampling" method, this paper studied the scale-dependency of the spatial variability of soil surface moisture in the woodland and farmland in the oasis ecological system in the middle reaches of Heihe River. The results showed that the variation degree of the surface soil moisture in the test woodland and farmland increased with increasing soil moisture content, and the coefficient of variation (CV) became closer to the true value when the sampling scale increased. Under both dry and moist conditions, and when the sampling amplitude increased within a definite range, the CV, Moran's I index, nugget, and sill of soil moisture in the woodland and farmland as well as the variation range in the woodland all increased, while the variation range in the farmland under arid condition did not show a stable regular pattern. When the sampling density increased within a definite range, the nugget and variation range increased, but the CV, Moran's I index, and sill showed less change.