Lead contamination in Chinese surface soils: Source identification, spatial-temporal distribution and associated health risks

Soil lead (Pb) pollution is wide spread in China. The Chinese government is taking ambitious actions to tackle the soil pollution issue, with the latest soil quality standards and the Soil Pollution Prevention and Remediation Law enacted in 2018. This study assesses the spatio-temporal distribution, pollution levels, major sources and health risks of Pb in surface soils in China in the past three decades (1990–2017). Traffic emissions (mainly leaded gasoline), mining, smelting, and e-waste recycling were main contributors to soil Pb pollution and pose a risk to food security and human health. The weighted arithmetic mean of Pb concentrations was 35.9 ± 0.21 mg/kg. Southern China suffered from severer soil Pb pollution with hotspots of the Pearl River Delta, Yangtze River Delta, Shaanxi and Hunan. The average soil Pb concentration increased marginally during 1990–2001 due to increased industrial and transportation activities; afterwards, it decreased by ∼30% during 2001–2013, reflecting the effectiveness of the ban on leaded gasoline in 2000. However, there was a slight increase in recent years. Therefore, it is critical to establish a comprehensive evaluation and monitoring system, strengthen pollution source control, properly manage the environmental and health risks at severely contaminated sites, and conduct green and sustainable remediation.