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区域环境与生态

Concentrations and bioavailability of polyhalogenated biphenyls in sediments from Yongding New River in Tianjin,China

摘要：通过测定天津市永定新河沉积物和同步采集的溞体内多氯联苯(PCBs)和多溴联苯(PBBs)含量,初步评价此类持久性有机污染物的潜在生态风险.结果显示,经归一化处理后,在永定新河沉积物中主要检出的18种PCBs和14种PBBs总含量分别为492.4～3251.9ng·g^-1和429.7～2950.0ng·g^-1(以有机碳计),而在溞体内PCBs和PBBs的总含量分别是301.8～1765.4ng·g^-1和309.7～1987.8ng·g^-1(以脂肪计).计算得到的PCBs和PBBs沉积物生物富集系数(BSAF)分别在0.1～1.3和0.1～3.0之间,明显小于根据平衡分配模型的预测值和其他文献报道值.同时,BSAF数值与相应污染物的辛醇/水分配系数的对数(logK_ow)值之间无相关关系(p>0.08),且在不同采样点间的变异系数相差较大(20%～90%).研究结果还表明,与国内外已经发表数据相比,永定新河沉积物中PCBs和PBBs均处在较高污染水平,但是绝大部分目标污染物的BSAF数值偏低,沉积物结合态污染物的生物有效性相对较低,且在不同采样点间存在着较大差异.

Abstract：Concentrations of polychlorinated biphenyls(PCBs)and polybrominated biphenyls(PBBs)in sediments and simultaneously sampled daphnia from Yongding New River in Tianjin,China were determined to preliminarily assess their potential ecological risks.According to the results,18 PCB congers and 14 PBB congeners could be detected in all sediment samples,and their total concentrations ranged from 492.4 to 3251.9 ng·g^-1 and 429.7 to 2950.0 ng·g^-1(normalized to total organic carbon),respectively.Their concentrations in daphnia samples were from 301.8 to 1765.4 ng·g^-1 and 309.7 to 1987.8 ng·g^-1(normalized to lipids),respectively.The calculated in-situ bio-sediment accumulation factors(BSAFs)of PCBs and PBBs ranged from 0.1 to 1.3 and 0.1 to 3.0,respectively.Most BSAFs were much lower than those predicted by equilibrium partitioning theory,and no significant relationship between BSAF and logK_ow(p>0.08)was found.It can be concluded that concentrations of PCBs and PBBs in sediments from Yongding New River were higher than many reported from other areas,but the bioavailability for most of sediment-associated PCBs and PBBs was low and varied greatly among different sampling sites(coefficients of variation:20%～90%).