多溴联苯醚微生物降解过程与机理的研究进展

多溴联苯醚(PBDEs)属溴代阻燃剂,曾因其优良的阻燃性能而广泛应用于电子电器、石油化工和建材纺织等工业产品中.然而,随着大量生产和使用,PBDEs已成为大气、水体、土壤和生物体等多环境介质中普遍检出且极具生态风险的有机污染物.因此,开展微生物降解研究对于典型环境中PBDEs污染风险消除和污染修复,具有重要的科学意义.本文从PBDEs环境归趋行为及其暴露风险出发,综述了PBDEs微生物厌氧降解和好氧降解的最新研究动态,比较分析了两种降解过程的降解特性与影响因素,并针对微生物,尤其是好氧微生物降解机理,阐述了bph A或etb A功能基因及其编码酶对PBDEs好氧降解过程的调控作用,同时就PBDEs微生物高效降解菌种选育、降解机理等方面的研究趋势进行了展望.     

莱州湾地区土壤及底泥中多溴联苯醚水平及其分布

对莱州湾地区十溴联苯醚生产厂家附近土壤及底泥中的多溴联苯醚的含量进行了检测.所采集土壤和河流底泥样品中Σ8 PBDEs(BDE-28、-47、-100、-99、-154、-153、-183、-209) 的含量在58.2～7190.7 ng·g-1(干重)之间, 所有样品中,BDE-209 相对含量最高,其对Σ8PBDEs 的贡献为74.81% ～99.01 %.在8种PBDEs同族体的相关性研究中发现BDE-209与BDE-183、-154、-153、-100、-99呈现显著负相关,相关系数r为-0.842～-0.996(α=0.01).BDE-183、-154、-153、-100、-99之间呈显著正相关,相关系数r为0.805～0.994(α=0.01).产品十溴联苯醚在环境中的降解可能是测定样品中BDE-99、-100、-153、-154、-183的来源之一.     

北京冬季大气中多溴联苯醚的污染水平和分布特征

2010年11月至2011年2月利用聚氨酯泡沫(PUF)大气被动采样技术采集了北京市海淀、朝阳、丰台、石景山、昌平、大兴、通州等区域的大气样品,采用高分辨气相色谱/高分辨质谱联用法(HRGC/HRMS)分析了其中13种多溴联苯醚(PBDEs)同族体的污染浓度和分布特征.结果表明,北京大气中PBDEs总含量(Σ13PBDEs)为0.97~41.1pg/m3,平均值为7.85pg/m3.在区域分布规律方面呈现东南地区的采样点污染物浓度明显高于西北地区,工业地区和人口密集的商业地区明显高于郊区和背景对照区的分布特征.     

多溴联苯醚的生物富集效应研究进展

研究污染物的生物富集效应对于预测污染物在生物体内的含量、建立环境标准以及评估污染物的生态风险具有重要的意义.论文结合近年来国内外有关多溴联苯醚(PBDEs)的生物富集及其沿食物链(网)生物放大效应的研究文献,对PBDEs的生物富集效应进行了综述.文献计算的生物富集因子(BAFs)、生物-沉积物/土壤生物富集因子(BSAFs)和生物放大因子(BMFs)表明,生物对大多数PBDEs具有生物富集作用,且生物对PBDEs的富集能力与其生物进化等级及其营养级有关.文献计算的营养级放大因子(TMFs)表明,大多数PBDE单体可以在食物网上产生生物放大效应,但只有较少单体具有统计上的显著性.生物的生理生化参数、化合物本身的特性以及环境条件等因素影响了PBDEs在生物体内及食物链(网)上的富集与放大.     

电脑散热风扇灰尘中多溴二苯醚的污染特征和环境健康风险评价

以多溴二苯醚（PBDEs）为阻燃剂的电器的使用是室内灰尘中PBDEs的一个重要来源,其中,电脑是人们日常使用时间较长的电子设备之一.采集了主要电脑厂商过去十年间生产的笔记本和台式机内置散热风扇处的灰尘,研究了灰尘中PBDEs的含量、组成、来源及人体暴露量,并评价了其环境健康风险.结果表明,各主流品牌电脑均有部分样品∑PBDEs含量较高,显示其可能都曾使用PBDEs作为阻燃剂.组成上,笔记本和台式机均以BDE-209为主（笔记本：89.4%,台式机：93.3%）.53%的笔记本（19/36）和台式机（10/19）灰尘中∑PBDEs与室内降尘对照样的比值>1.其中,8台笔记本和2台台式机的比值>10（77±99和53±61）,表明部分电脑的组件中添加了PBDEs,其运行使用是室内环境中PBDEs的来源之一.人体通过灰尘摄入途径暴露于电脑释放源∑PBDEs的非致癌风险（HI）和BDE-209的致癌风险（CR）均比呼吸暴露途径高1~2个数量级,显示灰尘摄入在人体对电脑等室内PBDEs释放源的暴露中扮演主要角色.各暴露途径的暴露量均低于RfD,HI > 1和CR > 10^-6（可接受致癌风险的上限）的超标概率均小于0.000%,显示人体通过灰尘摄入和呼吸途径暴露于电脑释放源PBDEs的环境健康风险低,但由于人体对PBDEs暴露途径的多样性,其叠加后的暴露量和健康风险仍需进一步研究评估.BDE-209是我国人体经灰尘摄入和呼吸途径暴露于电脑释放源PBDEs的首要同系物.主要低溴BDE的暴露风险随溴代数降低而增加,BDE-209漫长复杂的自然降解所产生低溴BDE的环境健康风险值得继续关注.     

环境中多溴联苯醚分析方法的研究进展

多溴联苯醚(PBDEs)是一类性能优异的阻燃剂,被广泛添加到工业产品和日常生活用品中.研究表明很多PBDEs单体具有持久性有机污染物(POPs)的特性,其中五溴和八溴联苯醚已被列入POPs清单.它们在环境中广泛存在,对环境和生态系统带来健康风险.本文概述了环境中PBDEs的前处理方法和仪器分析的研究进展,对不同的方法进行了综述和比较,并提出了PBDEs分析方法研究的发展趋势.     

Renal lesions in Greenland sledge dogs ( Canis familiaris ) exposed to a natural dietary cocktail of persistent organic pollutants

Persistent organic pollutants such as Polychlorinated biphenyls (PCB) and dichloro diphenyl trichloroethane (DDT) are known to exert various adverse health effects in wildlife mammals. The impact from dietary intake of minke whale (Balaenoptera acutorostrata) blubber high in organohalogen and other chemical contaminants on renal morphology and function was investigated via a controlled study on West Greenland sledge dogs (Canis familiaris). Our results showed significantly higher frequencies of glomerular, tubular, and interstitial lesions in the exposed group. Furthermore, higher urine protein?:?creatinine ratio and plasma urea levels were found in the exposed group, which indicated a negative impact on kidney function via tubular and glomerular dysfunctions. The lesions were similar to those observed in top predator marine species–such as seals and polar bears–and humans exposed via diet to persistent environmental pollutants. The lesions may have impacts on the overall health of these animals. It is reasonable to suggest that chronic exposure to organic pollutants via a country diet of high trophic level marine organisms may have an impact on renal morphology and function in Arctic apex predators in general as well as Inuit people.     

有机氯农药和多溴联苯醚在白洋淀鸭子组织中分布特征研究

利用气相色谱-质谱(GC/MS)方法定量分析了白洋淀鸭子肌肉、肝脏、脑组织中HCHs、DDTs和PBDEs的分布特征.结果表明,3种组织中HCHs和DDTs的含量范围分别为0.9～5.0 ng/g(以湿重计,下同)和0.3～2.8 ng/g,而PBDEs的含量范围是0.03～0.65 ng/g.统计分析鸭子不同组织中持久性卤代烃的含量差异,结果显示,DDTs和PBDEs的含量水平有较大差异(p0.05);而HCHs在3种组织中的含量差异不明显(p0.05).肝脏中DDTs和PBDEs的平均含量较高,分别为2.3和0.37 ng/g.在HCHs和DDTs同系物(代谢物)组成中,β-HCH在肝脏和脑组织中占主要地位,p,p′-DDE是DDTs的主要代谢产物;在PBDEs同系物中,BDE47和BDE99是鸭子组织中主要的组成部分.鸭子不同组织中HCHs、DDTs和PBDEs的组成模式反映了白洋淀仍然受到历史残留的有机氯农药污染;同时,来自白洋淀上游的工业污染很可能输入新型持久性有机污染物(PBDEs).     

多溴联苯醚环境行为对生态环境的研究进展

多溴联苯醚PBDEs(polybrominated diphenyl ethers)是一种常用的阻燃剂,已被纳入POPs(persistent organic pollutants)名单。本文综述了PBDEs的环境行为研究进展,以期为未来研究提供参考。     

Oxidative transformation of polybrominated diphenyl ether congeners (PBDEs) and of hydroxylated PBDEs (OH-PBDEs)

BACKGROUND, AIM, AND SCOPE: The historical and widespread use of polybrominated diphenyl ethers (PBDEs) as flame retardants in consumer products worldwide has caused PBDEs to now be regarded as pervasive environmental contaminants. Most recently, hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have emerged as environmentally relevant due to reports of their natural production and metabolism. An important parameter for assessing the environmental impact of a chemical substance is persistence. By formulating the concept that persistence is the result of the substance's physicochemical properties and chemical reactivity, Green and Bergman have proposed a new methodology to determine the inherent persistence of a chemical. If persistence could be predicted by straightforward methods, substances with this quality could be screened out before large-scale production/manufacturing begins. To provide data to implement this concept, we have developed new methodologies to study chemical transformations through photolysis; hydrolysis, substitution, and elimination; and via oxidation. This study has focused on adapting an oxidative reaction method to be applicable to non-water soluble organic pollutants. MATERIALS AND METHODS: PBDEs and one MeO-PBDE were dissolved in tetrahydrofuran/methanol and then diluted in alkaline water. The OH-PBDEs were dissolved in alkaline water prior to reaction. The oxidation degradation reaction was performed at 50 degrees C using potassium permanganate as described elsewhere. The pH was maintained at 7.6 with disodium hydrogen phosphate and barium hydrogen phosphate, the latter also serving as a trapping agent for manganate ions. The oxidation reactions were monitored by high-performance liquid chromatography and reaction rates were calculated. RESULTS: The OH-PBDEs have very fast oxidative transformation rates compared to the PBDEs. The reaction rates seem to be primarily dependent on substitution pattern of the pi-electron-donating bromine substituents and of bromine content. There are indications that further reactions of OH-PBDEs, e.g., methylation to the MeO-PBDEs, decrease the oxidation rates, and thereby generate more persistent substances. DISCUSSION: The resistance of PBDEs to oxidation, a major degradation pathway in air, should be further investigated, since these compounds do undergo long range transport. With slight modifications, the original method has been adapted to include a larger variety of chemical substances, and preliminary data are now available on the oxidative transformation rates for PBDEs and of OH-PBDEs. CONCLUSIONS: The original oxidation degradation method can now include non-water soluble compounds. This modification, using low concentrations of test chemicals, allows us to measure oxidative transformation rates, for some of the lower brominated DEs, data that can be used to assess their persistence in future model calculations. Oxidative transformation rates for PBDEs are slow compared to those for the OH-PBDEs. This suggests that OH-PBDEs, when released into the environment, undergo faster oxidative metabolism and excretion than the PBDEs. RECOMMENDATIONS AND PERSPECTIVES: To evaluate the modified method, more degradation reactions with non-water soluble compounds should be investigated. Recent studies show that OH-PBDEs are present in rats and in humans and, because of their activity as endocrine disruptors, determining their subsequent environmental fate is of importance. The resistance of PBDEs to oxidative degradation should be acknowledged as of possible future concern. Several other compound classes (such as polychlorinated biphenyls (PCBs), hydroxylated polychlorinated biphenyls (OH-PCBs), and pharmaceuticals) need to be subjected to this screening method to increase the database of transformation rates that can be used with this model.