Levels and distribution patterns of short chain chlorinated paraffins in sewage sludge of wastewater treatment plants in China

Short chain chlorinated paraffins (SCCPs) are listed as persistent organic pollutant candidates in the Stockholm Convention and are receiving more and more attentions worldwide. In general, concentrations of contaminants in sewage sludge can give an important indication on their pollution levels at a local/regional basis. In this study, SCCPs were investigated in sewage sludge samples collected from 52 wastewater treatment plants in China. Concentrations of total SCCPs (ΣSCCPs) in sludge were in the range of 0.80–52.7 μg/g dry weight (dw), with a mean value of 10.7 μg/g dw. Most of SCCPs in the sludge samples showed a similar congener distribution patterns, and C11 and Cl7,8 were identified as the dominant carbon and chlorine congener groups. Significant linear relationships were found among different SCCP congener groups (r2 ≥ 0.9). High concentrations of SCCPs in sewage sludge imply that SCCPs are widely present in China.

► Levels and distribution patterns of SCCPs were studied in sewage sludge in China.
► Concentrations of total SCCPs in sludge ranged from 0.8 to 52.7 μg/g dry weight.
► C11 and Cl7,8 were identified as the dominant congener groups within SCCPs.
► Significant linear relationships were found among SCCP congener groups (r2 ≥ 0.9).
► SCCPs are present in household products and can be exposing to human.