Short- and medium-chained chlorinated paraffins in soils and sediments in China: Spatiotemporal distributions,...

Comprehensive analysis of the spatiotemporal distributions, homolog patterns, ecological risks, and driving mechanisms of short-chained chlorinated paraffins (SCCPs) and medium-chained chlorinated paraffins (MCCPs) in Chinese soils and sediments is crucial for pollution identification and risk control. This study collected and analyzed literature published from 2011 to 2024, including information on SCCPs and MCCPs in soils and sediments from about 130 cities in 32 provinces of China. The results showed that SCCP and MCCP contamination in soils was mainly low-risk. In contrast, the sediment results were mainly medium-risk, with medium- and high-risk sites primarily distributed in China's eastern and central provinces. From 2006 to 2022, the contents of chlorinated paraffins (CPs) in soils and sediments in the study cases in China showed a gradual upward trend in general, and the accumulation of SCCPs showed a stable or decreasing trend from about 2015. In Chinese soils and sediments, the proportion of CP congeners with shorter carbon chains was more significant, among which C10 and C14 were the main carbon congeners of SCCPs and MCCPs, respectively. According to the geodetector, the accumulation of SCCPs and MCCPs was influenced by a combination of pollution sources, diffusion pathways, and receptor attributes, with population density, normalized difference vegetation index (NDVI), and soil type being the main drivers. These results provided a reference for the changing characteristics and influencing factors of SCCP and MCCP contamination in soils and sediments nationwide.