Overview of heavy metal pollution and health risk assessment of urban soils in Yangtze River Economic Belt, China

Using national multi-purpose regional geochemical survey (NMPRGS) data, this overview systematically summarizes the pollution levels and health risks posed by 8 heavy metals (As, Cd, Pb, Zn, Hg, Cu, Cr and Ni) in urban soils of 86 cities above the prefecture level in Yangtze River Economic Belt (YREB). Meanwhile, the spatial distribution and main sources of heavy metal pollutants in urban soils of key cities are described in detail. On a regional scale, Hg and Cd contamination in urban soils of YREB is most prominent, and As, Cu, Pb and Zn contamination exists in several cities, while Cr and Ni contamination is almost not shown. The type of industrialization and the history of urbanization affect the soil heavy metal pollution in majority cities, and the influence of geological background on the content of heavy metals in urban soils cannot be ignored. Specifically, the urban pollution of Cd, As, Pb and Zn is mainly concentrated in Hunan and Hubei Provinces, which are highly developed in mining industry, especially in Zhuzhou, Chenzhou, Huangshi and Xiangtan cities, while the major soil Hg pollution occurs in Zhejiang and Jiangsu Provinces with rapid economic development, where Shaoxing, Ningbo, Suzhou and Wuxi are the key polluted cities. Heavy metals in the urban soils investigated generally posed low non-carcinogenic and carcinogenic risks to the adults. However, the non-carcinogenic risk to minors in some cities (e.g., Chenzhou and Huangshi) should be given cautious attention.