Spatial distribution, homologue patterns and ecological risks of chlorinated paraffins in mangrove sediments along the South China Coast

The spatial distribution, homologue patterns, and ecological risks of chlorinated paraffins (CPs) were investigated in sediments from sixteen mangrove wetlands along the South China Coast (SCS). The total concentrations of CPs in mangrove sediments from Guangdong, Fujian, Guangxi, and Hainan were in the range of 933-4760, 619-2300, 375-1550, and 271-658 ng/g dry weight, respectively. The contamination levels and spatial distribution of short-chain and medium-chain CPs (SCCPs and MCCPs, respectively) in mangrove sediments were mainly affected by local population scale and CP industries. The dominant CP patterns in sediments were C10-11Cl6- 8 and C14Cl7-9 for SCCPs and MCCPs, respectively. Redundancy analysis, based on CP levels and several potential influencing factors showed that MCCPs/SCCPs ratio was the main factor affecting the accumulation of CPs in mangrove sediments. Additionally, MCCP concentrations were significantly correlated with total organic carbon (TOC), indicating that TOC might affect MCCP accumulation in mangrove sediments. Risk assessments indicated that CPs would pose medium ecological risks to sediment dwelling organisms in nearly one-third of the sampling sites. This is the first comprehensive report of the sedimentary SCCPs and MCCPs in mangrove wetlands along the SCS and highlights the need for more sediment toxicity data for CPs.

Automated summary

This study investigated the spatial distribution, homologue patterns, and ecological risks of chlorinated paraffins (CPs) in sediments from sixteen mangrove wetlands along the South China Coast. The results showed that the concentrations of CPs were influenced by local population scale and CP industries. Risk assessments indicated medium ecological risks of CPs to sediment dwelling organisms in nearly one-third of the sampling sites. This is the first comprehensive report on SCCPs and MCCPs in sediment from mangrove wetlands along the South China Coast.