Spatial distributions, source apportionment and ecological risks of C-C chlorinated paraffins in mangrove sediments from Dongzhai Harbor, Hainan Island.

The spatial distributions, possible sources of C-C chlorinated paraffins (CPs), and the ecological risks posed in mangrove sediment in Dongzhai Harbor (Hainan Island, China) were investigated. Comprehensive two-dimensional gas chromatography combined with electron capture negative ionization mass spectrometry was used to determine 50 C-C CP congener groups. The concentrations of C-CPs, short-chain CPs (SCCPs), and medium-chain CPs (MCCPs) in the mangrove sediment samples were 8.28-79.7, 89.2-931, and 58.8-834 ng g dry weight, respectively. The CPs concentrations in the mangrove sediment samples were moderate compared with those found in other regions worldwide. The spatial distributions and congener patterns of the CPs indicated that the CP concentrations were mainly controlled by local emissions and that wastewater discharged from livestock and shrimp breeding facilities and domestic sewage were the main sources of CPs in mangrove sediment in Dongzhai Harbor. CCl and CCl were the dominant SCCP and MCCP congener groups, respectively. The MCCP concentrations and total organic carbon contents significantly correlated (R = 0.607, P < 0.05). Hierarchical cluster analysis and principal component analysis indicated that the SCCP and MCCP congeners were from different commercial CP formulations and sources. Risk assessments suggested that SCCPs and MCCPs in mangrove sediment in Dongzhai Harbor do not currently pose marked risks to sediment-dwelling organisms.