Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
Ningbo Key Laboratory of Urban Environmental Processes and Pollution Control, Ningbo Urban Environment Observation and Research Station, Chinese Academy of Sciences, Ningbo, 315800, China.
Environ Sci Pollut Res Int. 2018 Jul;25(21):20823-20832. doi: 10.1007/s11356-018-2254-1. Epub 2018 May 14.
Hexabromocyclododecanes (HBCDs) are a class of widely used brominated flame retardants (BFRs) that exhibit strong hydrophobicity. The ubiquity and persistence of HBCDs in sediment have attracted significant attention because of public health concerns. The environmental fate and ecological risks of HBCDs closely depend on their phase distribution in sediments. However, little information is available regarding the freely dissolved concentrations (C) of HBCDs in sediment porewater. In this study, we developed a method to measure C of HBCDs in sediment porewater using triolein-embedded cellulose acetate membranes (TECAM). The TECAM-to-water partitioning coefficient (log K) was 4.69, 4.77, and 4.63 for α-HBCD, β-HBCD, and γ-HBCD, respectively. In sediments, HBCDs sorbed to the sediment solid phase accounted for more than 99% of the total chemical mass. The dissolved organic carbon (DOC)-water partition coefficient (K) values were derived from TECAM measurements, and the log K values ranged from 5.77 to 6.23 for the three HBCD diastereomers, suggesting a strong tendency for HBCDs to sorb to DOC. The high sorption of HBDCs for DOC implies a potential for DOC-facilitated transport which may enhance the environmental mobility of HBCDs.
六溴环十二烷（HBCDs）是一类广泛使用的溴系阻燃剂（BFRs），具有很强的疏水性。由于公众对健康的关注，HBCDs 在沉积物中的普遍存在和持久性引起了极大的关注。HBCDs 的环境归宿和生态风险与其在沉积物中的相分布密切相关。然而，关于 HBCDs 在沉积物孔隙水中的自由溶解浓度（C）的信息很少。在本研究中，我们开发了一种使用三油酸甘油酯嵌入醋酸纤维素膜（TECAM）测量 HBCDs 在沉积物孔隙水中的 C 的方法。TECAM 与水的分配系数（log K）分别为α-HBCD、β-HBCD 和 γ-HBCD 的 4.69、4.77 和 4.63。在沉积物中，HBCDs 吸附到沉积物固相的比例超过了总化学质量的 99%。通过 TECAM 测量得到了溶解有机碳（DOC）-水分配系数（K）值，三种 HBCD 非对映异构体的 log K 值范围为 5.77 至 6.23，表明 HBCDs 强烈倾向于吸附到 DOC。HBDCs 对 DOC 的高吸附性意味着存在 DOC 促进传输的潜力，这可能会增强 HBCDs 的环境迁移性。
