| With the restrictive usage of Polybrominated diphenyl ethers(PBDE) by the Stockholm Convention, the novel BFRs, including non-polybrominated diphenyl ethers(non-PBDE), heterocyclic brominated flame retardant tris(2, 3-dibromopropyl) isocyanurate(TBC), and hexabromocyclododecane(HBCD), were applied extensively in production process and daily life in recent years. However, the research on non-PBDE, TBC, and HBCD at home and abroad was still in its initial stage, and still needs further development. In this study, the Jiaozhou Bay wetland was selected as environment model, and the concentration, main pollution sources, and composition characteristics of BFRs in sediment and plant samples were studied and analyzed. Moreover, the correlation analysis and principal component analysis of SPSS software were adopted to analyze the correlation, migration and transformation among non-PBDE in Jiaozhou Bay wetland. This study not only provides the theoretical basis for further investigation on the source, migration and transformation of novel BFRs in sediment and plants, but also offers the technical and scientific support to deep studies on BFRs. The main content and results of this research were summarized as follows.This paper optimized the pretreatment method of sediment and plant samples, and the detection method of gas chromatography mass spectrometry(GC-MS), recpectively. Then, we chose the best analysis conditions of soxhlet extraction, composite silica gel chromatography and GC-MS separation, discussed the indexes such as liner equations, correlation coefficients, limit of detection, limit of quantification, average recovery, and relative standard deviations of seven kinds of non-PBDE, and analyzed the occurrence and distribution characteristics of non-PBDE BFRs in Jiaozhou Bay wetland.Sediment and plant samples from Jiaozhou Bay wetland were extracted by soxhlet extraction, ultrasonic extraction and cleaned by composite silica gel column. With BDE30, PCB209 L added as surrogate compound, and BDE118 as internal standard, the concentration of seven kinds of non-PBDE in sediment samples, including TBB, TBX, PBT, PBEB, HBB, DBHCTD and BB153, was analyzed by GC-MS.The results indicated that the limit of detection was 0.03-0.18 ng·g-1, and the limit of quantification was 0.09-0.69 ng·g-1. Futhermore, the average recoveries spiked compounds in the sediment were 80 %-107 % while the recoveries of BDE30 and PCB209 L were 80 %-95 %, 85 %-105 %, respectively. Six kinds of non-PBDE, including TBB, PBT, PBEB, HBB, and DBHCTD, were detected in sediment, with the concentration of 0.41-9.66 ng·g-1(dry weight, dw). Besides, four kinds of non-PBDE(TBB, TBX, PBT, HBB) were detected in plant, and the concentration was 0.148-1.05 ng·g-1 dw.As shown in the results, DBHCTD has the highest concentration among the seven kinds of non-PBDE, which means DBHCTD was the main non-PBDE compared with other target compounds in Jiaozhou Bay wetland. This is mainly because DBHCTD has high accumulation efficiency in wetland.Pearson correlation analysis for non-PBDE was carried out by SPSS software. The results showed that the Pearson correlation coefficient(r) between DBHCTD and other four kinds of non-PBDE(TBB, PBEB, HBB, and PBT) are greater than 0.567(P<0.01). Specially, a significant linear relationship was found between DBHCTD and PBT, and the Pearson correlation coefficient(r) is equal to 0.892(P<0.01). This indicated that they may have a common source or similar accumulation potential in sediments.The spatial distribution of non-PBDE was shown as follows:The concentration of non-PBDE would decrease gradually with the increasing distance from Xiaojianxi landfill to the north shore of Jiaozhou Bay intertidal. However, some sites are exception as electroplate factory, furniture processing factory, food processing factory, sewing clothes factory, and fishing factory were built around the sites. Moreover, there were some ditches around Taoyuan river and Dagu river. Both the wastewater from these factories and the leachate from those ditches mentioned above were poured into the Taoyuan river, and then flowed into the Dagu river, which could carry a lot of organic pollutants into Jiaozhou Bay. As a result, the concentration of non-PBDE in some sites became higher.The species of non-PBDE were different in sediment and plant samples. Generally, the concentration of non-PBDE in sediment was higher than that in plant for most of the non-PBDE detected in this study. This is mainly due to:a The adsorption capacity of non-PBDE in sediment is stronger than plants;b The log Kow values range between 4 and 8 for the non-PBDE, leading to a poor gastrointestinal absorption in sediment samples;c The accumulation of non-PBDE might be influenced by air transportation.In this study, sediment samples were extracted by Soxhlet extraction and cleaned by composite silica gel column. With 13C12-γ-HBCD added as surrogate compound, and 2H18-γ-HBCD as internal standard, the content of TBC and HBCD in sediment was analyzed by liquid chromatography mass spectrometry(LC-MS). Futhermore, their distribution in Jiaozhou Bay wetland was also studied.The concentration of TBC, α-HBCD, β-HBCD, and γ-HBCD in sediment was in the range of 1.2-8.764, 1.034-5.689, 1.132-5.463, 1.181-15.04 ng·g-1 dw, respectively. Among the three diastereoisomers of HBCD, γ-HBCD was the major isomeride with the concentration of 1.18-15.04 ng?g-1 dw, and the proportion of γ-HBCD was 52.42 % in ∑HBCD.The geographical distribution of TBC and HBCD showed a decreasing trend from Xiaojianxi refuse landfill to the north shore of Jiaozhou Bay intertial. However, as the surrounding geographical environment is different, the contamination in the downstream was higher than that in the upstream. This might because Jiaozhou Bay wetland has the adsorption capacity for organic pollutants.Compared with other seven rivers in China, such as Liaohe River, Haihe River, Tarim River, Pearl River, Yangtze River, Ertix River and the upper Yellow River, the content of HBCD in Jiaozhou Bay wetland was at a relatively high level, which was similar to Yangtze River and Pearl River. |
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