Studies On Polybrominated Diphenyl Ethers And Organophosphate Esters In Sediments Of Shanghai

Polybrominated diphenyl ethers(PBDEs) are category of persistent organic pollutants(POPs) which are widespread in different environmental mediums. Organophosphate esters(OPEs), as new alternative, continuously spread to the environment and cause increasingly serious pollution. PBDEs and OPEs have been detected in different environment mediums. The contamination levels, spatial distribution, compositional profiles, possible sources and potential ecological risk of PBDEs and OPEs from 116 sediments in rivers and Yangtze River estuary from Shanghai were systematically investigated. The study aimed to understand the sediment contamination status and potential risk posed by PBDEs and OPEs in Shanghai, and to provid the scientific basis for pollution control and management of PBDEs and OPEs. The main conclusions are summarized as follows:1. Fifty-two PBDE congeners were analyzed in the present study. The concentrations of Σ51BDEs(defined as the sum of 51 BDE congeners except BDE209) and BDE209 ranged from 0.231 to 119 ng g-1 dw and from nd to 189 ng g-1 dw in river sediments from Shanghai, respectively. The mean values were 7.19 and 13.2 ng g-1 dw, respectively. The most abundant BDE congeners in surface sediments were BDE118, 207, 208, 99, 49, 75, 47, 71 and 209, with median values of 1.67, 1.81, 1.83, 1.87, 1.98, 2.52, 2.73, 4.62 and 45.7 ng g-1 dw, respectively. The concentrations of Σ51BDEs and BDE209 ranged from 0.071 to 62.8 ng g-1 dw and from nd to 609 ng g-1 dw in Yangtze River estuary from Shanghai, respectively. The mean values were 4.90 and 17.0 ng g-1 dw, respectively. The most abundant BDE congeners in surface sediments were BDE15, 47, 71, 75, 99, 118, 207, 208 and 209, with median values of 0.023, 0.053, 0.055, 0.028, 0.028, 0.094, 0.062, 0.056 and 0.785 ng g-1 dw, respectively. Some high concentrations sediment samples distributed in Huangpu river. Some high concentrations sediment samples distributed in upstream from Yangtze River estuary.2. To identify the potential possible sources of PBDEs in sediment. Correspondence analysis(CA) was used to compare PBDE homologue profiles of sediment samples in river sediments from Shanghai. The PBDE homologue profiles of five major groups obtained from CA based on the mole fractions of PBDEs in river sediments. Principal Component Analysis and cluster analysis were used to study PBDE homologue profiles of sediment samples in Yangtze River estuary which there were three major groups. PBDEs in sediments in the studied area originated from commercial BDE formulations, combustion emission sources, and debromination of highly brominated PBDEs by aerobic/anaerobic microbes or sunlight.3. 11 OPEs could be detected in all sediment samples in the present study. The concentrations of Σ11OPEs ranged from 62 to 280 000 ng kg-1 dw in river sediments from Shanghai. The concentrations of Σ11OPEs ranged from 216 to 87 500 ng kg-1 dw in Yangtze River estuary. The compositional profiles revealed that TBEP was the main pollutant, followed was TCEP. Furthermore, the composition proportions of alkyl phosphates were highest, followed were chlorinated phosphates, aryl phosphates were the lowest.4. The concentrations of Σ52BDEs were significantly correlated with total organic carbon(TOC) content in sediments(p < 0.05). Weak correlations between all PBDE homologues and TOC(r < 0.32) suggested that TOC had a little influence on sediment PBDE transport and distribution patterns in river sediments of Shanghai. The concentrations of Σ52PBDEs were no significantly correlated with TOC content in sediments(p > 0.6). Weak correlations between all PBDE homologues and TOC(r < 0.18) suggested that TOC had a little influence on sediment PBDE transport and distribution patterns in Yangtze River estuary. The concentrations of Σ11OPEs were significantly correlated with TOC content in sediments(p < 0.01) in river sediments of Shanghai. Except TCP and TPP, other OPEs were significantly correlated with TOC content in sediments(p < 0.05). The concentrations of Σ11OPEs were significantly correlated with TOC content in sediments(p < 0.01) in sediment samples from Yangtze River estuary. The results suggested that TOC had a important influence on sediment OPEs transport and distribution patterns in sediments.5. Federal Sediment Quality Guidelines(FSe QGs) set by Canda for the protection of sediment dwelling animals as well as pelagic animals which bioaccumulate PBDEs from sediments were used for the assessment of ecological risk of PBDEs in sediments. Risk assessment based on risk quotients(RQ) showed that PBDEs in sediments from Shanghai rivers and Yangtze River estuary posed a high potential ecological risk(RQ >1) to the sediment dwelling organisms, and penta BDE, deca BDE and tetra BDE were the major ecological risk drivers. Referred to Tri-service Procedural Guidelines for Ecological Risk Assessments set by America, a risk assessment considering joint effect was performed calculating and summing risk quotients(RQs) for the sediment samples. ΣRQs of 26 sediment samples from Shanghai river were between 1.0 to 10. ΣRQs of 8 sediment samples from Yangtze River estuary were between 1.0 to 10. The results indicated a small potential for adverse effects.