大兴安岭南麓环境介质中多溴联苯醚的分布特征及风险评估

Distribution Characteristics and Risk Assessment of Polybrominated Diphenyl Ethers in Environmental Media in the Southern Foothills of Daxing’anling Mountains

大兴安岭南麓是我国北方草原向森林过渡的重要生态带,为了解该区域内环境中典型持久性有机污染物的分布特征及其潜在的环境风险,采集大兴安岭南麓土壤、凋落物和树皮等环境样品,分析不同环境介质中多溴联苯醚(PBDEs)的含量、组成及分布规律。结果表明:大兴安岭南麓土壤、凋落物和树皮中均检测出PBDEs存在,其中土壤中共检测到25种PBDE单体,∑PBDEs质量比为69.86~471.6 pg·g^(-1),平均值为190.1 pg·g^(-1);凋落物中共检测到15种PBDE单体,∑PBDEs质量比为30.72~258.2 pg·g^(-1),平均值为153.6 pg·g^(-1);活树皮中∑PBDEs质量比高于死树皮中的,平均分别为216.0和115.4 pg·g^(-1);不同环境介质中PBDEs组成均以一溴联苯醚、二溴联苯醚等低溴代联苯醚为主。危险商值法评价结果显示大兴安岭南麓环境中PBDEs污染处于较低水平,且主要以低溴代同类物为主,生态风险较低。大气长距离迁移沉降可能是该地区不同环境介质中PBDEs的主要来源。

The southern foothills of Daxing’anling Mountains are an important ecological zone for the transition from grassland to forest in the north of China.In order to understand the distribution characteristics of typical persistent organic pollutants and their potential environmental risks in this area,the soil,litter and bark samples were collected to analyze the content,composition and distribution patterns of polybrominated diphenyl ethers(PBDEs)in different environmental media.The results show that PBDEs are detected in the soil,litter and bark of the southern foothills of Daxing’anling Mountains.25 PBDEs are detected in the soil,with∑PBDEs concentrations ranging from 69.86 to 471.6 pg·g^(-1)and the average value of 190.1 pg·g^(-1).15 PBDEs were detected in the litter,with∑PBDEs concentrations ranging from 30.72 to 258.2 pg·g^(-1)and a mean value of 153.6 pg·g^(-1).The∑PBDEs concentrations in the live bark are higher than that in the dead bark,with mean concentrations of 216.0 and 115.4 pg·g^(-1),respectively.The composition of PBDEs in different environmental media is dominated by low-brominated biphenyl ethers such as mono-brominated biphenyl ethers and di-brominated biphenyl ethers.The evaluation results of the hazard quotient method show that the pollution of PBDEs in the environment of the southern foothills of Daxing’anling Mountains is at a low level,and is mainly composed of low brominated analogues with low ecological risk.The atmospheric long-range transport and deposition may be the main source of PBDEs in different environmental media in this region.