Distribution, homologue pattern, sources, and environmental behavior of short-chain chlorinated paraffins in multi-media environments within the petrochemical industry of the Yangtze River Delta

Abstract

Short-chain chlorinated paraffins (SCCPs) are widely found in the environment. However, limited information exists on the inter-media exchange and migration of SCCPs in the same region. In this study, a comprehensive survey of SCCPs was performed on various environmental substrates (including the surface soil, groundwater, and air) from a large petrochemical park in the Yangtze River Delta, and a total of 24 congener groups were measured. The SCCP concentrations, spatial variations, congener group profiles, and environmental behaviors during the water–land–atmosphere cycle in a typical industrial area were investigated. The ΣSCCP concentrations in the surface soil and groundwater within the petrochemical factory and in the atmosphere in the petrochemical factory perimeter were 108–745 ng g⁻¹, 1133–2994 ng L⁻¹ and 12.1–30.5 ng m⁻³, respectively. The concentrations and homologue patterns of SCCP significantly varied across different sampling sites, which was attributed to the distances between the sampling sites and workshops, as well as the diverse CP products or byproducts involved in the processing activities. The congener profile revealed that C₁₀Cl_8,9 and C₁₃Cl_8,9 were the major SCCP homologue groups in the soil within the petrochemical park, whereas C₁₀Cl_5–7 and C₁₃Cl_5–7 were the predominant congeners in the groundwater, and C_12,13Cl_7,8 was the dominant SCCP congener group in the atmosphere around the petrochemical park. With respect to the air-soil and soil–water exchange behaviors, the majority of fugacity fraction values for the air–soil and soil–groundwater samples were less than 0.3 and greater than 0.7, respectively, indicating the dominant deposition of SCCP congeners from the air to the soil and permeation into groundwater from the soil within the petrochemical park. To date, the preliminary risk assessments have indicated that SCCPs pose a low ecological risk in the petrochemical zone and pose a low risk to humans through dust ingestion and dermal contact.