RESUMO
Commercial chlorinated paraffins (CPs) are a source of CPs in the environment, and clarification of the different CP groups present in commercial products is important for source characterization. Resolving CP congener groups is hindered by the complex CP compositions of commercial products. We used comprehensive two-dimensional gas chromatography coupled with electron capture negative ionization high-resolution time-of-flight mass spectrometry to profile 57 C8 - C17 CP congener groups in 18 CP-42, CP-52, and CP-70 commercial products. Very short-chain CPs (vSCCPs), including C8Cl5-8 and C9Cl5-9 CPs, and other chlorinated aromatic compounds were identified in the commercial products. The mass fractions of total vSCCPs, short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) in the commercial products ranged from 0.02% to 3.61%, 0.75% to 51.4%, and 0.39% to 69.1%, respectively. Two-dimensional hierarchical cluster analysis with a heat map plot highlighted variations in the C8 - C17 CP congener group patterns among different commercial CP formulations. The principal component analysis results indicated that commercial CPs products might be important contributors to vSCCPs, SCCPs, and MCCPs in various environmental matrices. This study provides comprehensive and well-resolved compositional data for CPs in commercial products, which will be helpful for CP source characterization.
RESUMO
The spatial distributions, possible sources of C9-C17 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 C9-C17 CP congener groups. The concentrations of C9-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-1 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. C10Cl6-7 and C14Cl7-8 were the dominant SCCP and MCCP congener groups, respectively. The MCCP concentrations and total organic carbon contents significantly correlated (R2 = 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.