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1.
分子连接性指数法预测多氯联苯醚(PCDEs)的理化性质   总被引:6,自引:0,他引:6       下载免费PDF全文
通过计算多氯联苯醚(PCDEs)所有209种可能分子结构的分子连接性指数,以106种PCDEs理化性质的实验值为建模样本,建立并优选了PCDEs的饱和蒸气压(POL)、水溶解度(Sw)和正辛醇/水分配系数(Kow)的定量结构--性质相关(QSPR)方程,检验结果表明方程相关性显著.在此基础上对其余103种文献中尚未报道实验值的PCDEs的上述参数进行了预测.利用得到的预测值,进一步给出了另外3种理化性质--亨利常数(H)、空气/水分配系数(Kgw)、空气/正辛醇分配系数(Kgo)的计算结果.   相似文献   

2.
以采用MINDO/3、MNDO和AMI算法计算的17种多环芳烃(PAHs)的前线分子轨道能为分子结构参数,进行了这些PAHs光解速率常数的定量结构-性质相关(QSPR)的研究,并与基于PM3算法得到的QSPR模型进行了比较,研究结果表明,应用PM3算法得到的前线分子轨道能进行这些PAHs光解速率常数QSPR拟合的结果最好,其次是AMI算法,而MINDO/3和MNDO算法得到的结果较差。  相似文献   

3.
尽管持久性有机污染物多溴联苯醚(PBDEs)具有疏水性,土壤和沉积物对其有很强的固着能力,仍然在地下水中检测到PBDEs污染物,其中,可溶性有机质胡敏酸(HA)与PBDEs的相互作用可能是影响PBDEs在土壤—地下水中迁移的关键。为揭示HA作用对PBDEs环境行为的影响机理,文章基于Hyperchem软件平台,构建HA和PBDEs的三维分子结构,计算并对比作用前后结构参数的变化,结果发现:(1)PBDEs分子结构在水环境中是不稳定的;(2)随着溴原子个数的增加,PBDEs的表面积、体积、疏水性和极性增大,PBDEs疏水性在4.27~11.39之间,远大于HA(-0.95);(3)HA对PBDEs的影响主要通过氢键或羟基发生,作用后,HA和PBDEs的分子空间构型都发生了改变,PBDEs的栅格表面积、体积和极性均增强,而疏水性降低到2.63~8.99之间。研究显示HA作用改变了PBDEs三维分子结构,导致其疏水性减弱,从而促进了PBDEs在水环境中的迁移。  相似文献   

4.
为准确评估济南市夏季环境空气中PBDEs(多溴联苯醚)的污染情况,利用气相色谱-负化学离子源-质谱(GC-NCI-MS)方法,对采集到的大气颗粒物滤膜和气相样品进行了分析,得到不同粒径颗粒相和气相PBDEs在济南市夏季环境空气中的质量浓度.结果表明:观测期间,济南市环境空气中TSP(总悬浮颗粒物)、PM10和PM2.5中的ρ(PBDEs)分别为(224.1±14.0)(156.5±43.7)(110.2±27.4)pg/m3,质量浓度较高的3种PBDEs单体分别为BDE209、BDE99、BDE183;气相中ρ(PBDEs)为(54.8±13.2)pg/m3,其中,质量浓度较高的单体分别为BDE209、BDE47、BDE99.通过主因子分析发现,不同粒径颗粒物上吸附的PBDEs特征单体不同,TSP中以五溴联苯醚为主,PM10中以八溴联苯醚和五溴联苯醚为主,PM2.5中则以五溴联苯醚、八溴联苯醚、十溴联苯醚为主.通过将2种模型的预测值和实测值进行比较发现,稳衡态模型比KOA(辛醇-空气分配系数)模型更好地模拟了PBDEs的气-粒分配情况.在稳衡态模型下,PBDEs在气-粒分配中接近于平衡状态.高溴代PBDEs主要分布于颗粒相中,而低溴代PBDEs的真实情况不同于理论预测结果,BDE99及BDE47在颗粒相的分配比高于50%,说明济南市低溴代PBDEs也容易吸附在颗粒相中.根据计算的PBDEs呼吸暴露水平可知,PM2.5上PBDEs呼吸暴露量占TSP呼吸暴露量的49.1%,儿童约是成人的1.5倍.济南市普通儿童和成人对BDE99最高总摄入量分别为234.78和169.57 pg/(kg·d),均低于BDE99最大允许摄入量260 pg/(kg·d).根据US EPA(美国环境保护局)发布的PBDEs健康风险评价方法(EPA/540/R/070/002),利用国内外相关参数分别计算空气吸入致癌风险指数发现,济南市夏季环境空气中PBDEs的致癌风险处于较低水平.研究显示,济南市夏季环境空气中不同粒径颗粒物PBDEs的质量浓度处于较低污染水平,其产生的潜在健康风险也较低.   相似文献   

5.
为探究北江中上游流域的阻燃剂污染状况和风险水平,采用气相色谱-串联质谱(GC-MS/MS)法测定了34个地表水样品和8个沉积物样品中31种阻燃剂的浓度,包括多溴联苯醚(PBDEs)、六溴环十二烷(HBCD)、四溴双酚A (TBBPA)这3种溴代阻燃剂和28种有机磷阻燃剂(OPFRs).采用风险熵法评估了水体中阻燃剂的生态风险,并结合日饮用剂量评估了健康风险.结果表明:(1)地表水中PBDEs和HBCD浓度范围分别为4.78~625.52、225.43~2 209.18 ng/L,未检出TBBPA;沉积物中PBDEs、HBCD和TBPPA含量范围分别为ND~11.82、121.13~395.86和ND~3.30 ng/g.(2)地表水中OPFRs浓度范围为85.80~992.82 ng/L,浓度最高的3种单体分别为TCEP、TPhP和TDCIPP;沉积物中OPFRs含量范围为102.19~748.17 ng/g,含量最高的3种单体分别为TEHP、EHDPP和TCPP.(3)对于地表水中已知毒性参数和健康数据的阻燃剂污染物,其生态风险总体处于中低水平,但BDE-100呈现出高风险,TTP呈...  相似文献   

6.
为精确描述二噁英分子的电子结构及其定量结构/性质相关关系(QSPRs),运用密度泛函理论,在B3LYP/6-311G**水平上,分别对多氯二苯并对二噁英(PCDDs)和多氯二苯并呋喃(PCDFs)进行了优化计算.相应量子化学参数,即平均分子极化率(α),熵(S),极化率和四极矩的张量分量(αxx,αyy,αzz和Qxx,Qyy,Qzz)用于该类化合物辛醇-水分配系数的QSPR研究,构建了2个单变量和1个双变量模型,其决定系数R2分别为0.962、0.950和0.951;其显著性检验因子F分别为509.759、379.498和186.234.PCDD/Fs在辛醇相-水相间的分配性质主要与分子体积因素有关,而电性因素的影响较小;不同模型预测值间的差异与模型中预测变量本身性质和实验值的有限性有关.经比较,本研究中所建立的3个QSPRs模型尽管只有1个或2个变量,但其结果与复杂的偏最小二乘分析(PLS)相近.  相似文献   

7.
采用气相色谱/质谱联用仪和健康风险评价模型,研究了北京居民日常接触的典型日用塑料制品中PBDEs(多溴二苯醚)的赋存特征及其人体健康暴露风险. 结果表明:①塑料盆、垃圾桶、塑料垫、塑料板凳、拖把、热水壶壳、给水管、采暖管、排水管、拖鞋、收纳箱、文件框等12种日用塑料制品中w(∑21PBDEs)为0.45~21.30 mg/kg,平均值为5.98 mg/kg. ②日用塑料制品中十溴二苯醚是主要的PBDEs同系物,w(十溴二苯醚)平均占w(∑21PBDEs)的82.51%; 九溴二苯醚是次要PBDEs同系物,平均占9.76%;三溴~六溴二苯醚质量分数较低,平均占1.77%,日用塑料制品生产过程中添加含十溴二苯醚的废弃阻燃塑料是引起PBDEs污染的主要原因. ③成人通过呼吸吸入、皮肤接触和手-口3种途径摄入的PBDEs暴露量分别为295.77、44.29、0.00 pg/(kg·d),儿童通过3种途径的PBDEs暴露量分别为769.55、40.83、1.91 pg/(kg·d)表明呼吸吸入是主要暴露途径. ④日用塑料制品中PBDEs对成人和儿童的释放暴露非致癌危害熵分别为2.28×10-4和5.46×10-4,低于美国标准中可接受风险熵(1.0),表明日用塑料制品中PBDEs对人体的健康风险影响很小.   相似文献   

8.
广州市室内尘土中多溴联苯醚的分布特点及来源   总被引:2,自引:1,他引:1       下载免费PDF全文
随机采集了广州市46个家庭和12个办公室内尘土样品,同时采集了17个室外尘土样品、2个电视机和2个电脑尘土样品并分析了室内尘土中多溴联苯醚(PBDEs)的含量、单体分布及来源.结果表明,家庭尘土中∑10PBDEs(BDE28,47,66,85,99,100,153,154,183,209之和)的含量为 564.3~9654ng/g,中值和均值分别为 2686,3407ng/g;办公室尘土中∑10PBDEs 的含量为 1737~4408ng/g,中值和均值分别为3133,3179ng/g.室内尘土中PBDEs的最主要单体为BDE209,分别占家庭尘土和办公室尘土∑10PBDEs的97.4%和99.0%.BDE47、99和183在室内尘土中含量也较高.大多数室内尘土中∑10PBDEs的含量高于室外,说明室内可能有重要的PBDEs释放源.室内尘土中PBDEs的主要工业品来源为十溴联苯醚,五溴联苯醚次之,八溴联苯醚较少.  相似文献   

9.
杭州市家庭室内空气中PBDEs的污染现状与特征   总被引:3,自引:0,他引:3  
分析评价了杭州市家庭室内空气中多溴联苯醚(PBDEs)的污染现状及特征.结果显示:杭州家庭客厅空气中气相和颗粒相PBDEs的总浓度平均值分别为52.57 pg·m-3,范围为21.37~83.47 pg·m-3、卧室浓度为43.78 pg·m-3,范围为28.72~58.75 pg·m-3,BDE-47和BDE-99是家庭室内空气中最重要的两种单体,占总浓度的62.75%.室内空气中气相PBDEs浓度是颗粒相的1.49倍.高层建筑中的PBDEs浓度与低层建筑差别不大,均处于较低水平.PBDEs的理化性质、环境条件是影响其气固分配的重要因素.  相似文献   

10.
对广州市主要的工业园以及清远电子垃圾回收拆解园周边空气中溴代阻燃剂(BFRs)进行了分析.结果表明,两地区大气中均以多溴联苯醚(PBDEs)和十溴二苯乙烷(DBDPE)为主(城市地区占比分别为30.0%和68.0%,电子垃圾区分别为74.5%和22.8%),其中PBDEs在城市地区和电子垃圾区的浓度中值分别为184和411pg/m3;DBDPE则分别为414和193pg/m3.在城市地区,PBDEs的浓度高值多出现在与机械、电子、装饰材料和汽车制造业有关的工业园,新型阻燃剂DBDPE高浓度则多在与机械和电子产品制造业相关的大气中,而1,2-二(2,4,6-三溴苯氧基)乙烷(BTBPE)可能受当地面源污染影响较大.城市地区低分子量的PBDEs的组成波动较大,与五溴联苯醚的禁用(直接排放减少)和来源复杂有关;而电子垃圾区低分子量PBDEs组成稳定,气-固相分配更接近平衡,说明来源较为单一.通过模型估算,城市地区的21个工业园每年约向空气中释放48.0kg的BDE209与163kg的DBDPE,4个电子垃圾拆解园每年约释放31.8kg的PBDEs与12.0kg的DBDPE.  相似文献   

11.
Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC-MS (Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 ismore toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.  相似文献   

12.
Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC–MS (Gas Chromatography−Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately.  相似文献   

13.
为探究PBDEs(多溴联苯醚)在昆明大气中的环境行为,于2014年3月对昆明8个采样点大气TSP(总悬浮颗粒物)和PM2.5样本进行了收集并利用GC-MS技术对其上附着的PBDEs的13种同系物进行了测定,进而对TSP和PM2.5上PBDEs的分布特征和潜在风险进行了分析.结果表明:附着在TSP上的∑PBDE浓度(多溴联苯醚的总质量浓度)的范围为21.10~175.00 pg/m3.而附着在PM2.5上的∑PBDE浓度范围为17.50~149.00 pg/m3,约占TSP中∑PBDE浓度的35.31%~85.14%,并且高溴化的同系物(BDE-138~BDE-209)比低溴化的同系物(BDE-17~BDE-99)更容易附着在PM2.5上,约占∑PBDE浓度的8.50%~61.60%.对大气颗粒物中PBDEs的潜在影响和空气吸入暴露剂量评估结果表明,成人和儿童对PBDEs的DEDair(呼吸日暴露量)分别在5.28~43.75和6.90~57.23 pg/(kg·d)之间,TDI(每日总摄入量)分别在114.78~951.09和150.00~1 244.13 pg/(kg·d)之间,远低于最低无害水平[1 mg/(kg·d)].BDE-99的TDI分别为11.09~72.39和14.35~94.57 pg/(kg·d),均低于最低摄入水平[260 pg/(kg·d)].研究显示,昆明市大气TSP和PM2.5上的PBDEs对人体不存在健康风险.   相似文献   

14.
长江中游沉积物中多溴联苯醚的污染特征及风险评价   总被引:4,自引:3,他引:1  
田奇昌  唐洪波  夏丹  王莎莎  高丽荣 《环境科学》2015,36(12):4479-4485
多溴联苯醚(PBDEs)具有高毒性和生物累积性,进入水体后易与有机质相结合,成为PBDEs污染物的重要归宿,对人类健康和水生生态系统造成潜在的危险.为揭示多溴联苯醚(PBDEs)在长江中游流域的污染现状,通过采集该地区流域内13个表层沉积物样品,采用高分辨气相色谱/高分辨质谱法(HRGC/HRMS)对沉积物中9种PBDEs同类物进行分析.结果表明该地区沉积物中9种PBDEs的含量范围(干重)约为46.1~326 pg·g~(-1),而BDE-99是其中最主要的贡献单体,平均贡献率约为51.6%;其次是BDE-47,约为19.6%.与国内外其他海域的研究相比,长江中游沉积物中PBDEs残留量处于较低水平.通过测定沉积物中总有机碳(TOC),研究结果发现PBDEs含量与TOC无明显的正相关关系.结合商值法对PBDEs的健康风险进行初步评估,结果表明,本研究中PBDEs对人体产生的健康风险较小.  相似文献   

15.
污水及污泥中多溴联苯醚的研究进展   总被引:3,自引:2,他引:1  
多溴联苯醚是一类溴代阻燃剂,包括三种主要的工业产品,五溴、八溴、十溴联苯醚.该物质曾广泛使用于电子、材料、家具等产品中.研究表明,在这些产品的生产、使用和处理过程中均会释放多溴联苯醚到周边环境中.多溴联苯醚具有持久性、可生物富集和长距离迁移,对人体和身体系统存在潜在危害,是一类新兴污染物.目前,这类物质中的部分化合物已...  相似文献   

16.
齐珺  牛军峰  王丽莉 《环境科学》2008,29(1):212-218
基于遗传算法(GA)的因子筛选和支持向量机(SVM)的非线性回归,提出了1种改进的有机物定量结构-性质相关(QSPR)建模方法--遗传-支持向量机(GA-SVM),并将其用于38种食品工业常用有机物正辛醇-水分配系数(Kow)的QSPR建模.结果显示,QSPR模型选取了分子量、Hansen极性、沸点、含氧率和含氢率5种参数;模型的预测值与实测值间的误差平方和(SSE)、均方差(RMSE)和决定系数(R2)分别为0.048、0,036和0.999,表明模型具有较强的预测能力;同时,交叉验证的结果(SSE=0.295,RMSE=0.089,R2=0.995)也表明,模型具有良好的稳健性,因此,GA-SVM算法适用于对有机物正辛醇-水分配系数的QSPR建模.此外,将基于GA-SVM的QSPR模型分别与基于遗传-径向基神经网络(GA-RBFNN)和基于线性算法的模型进行了比较,结果表明,应用GA-SVM建立的QSPR模型无论从稳健性还是预测能力上都优于应用其它2种算法建立的模型,因此,GA-SVM算法比GA-RBFNN和线性算法更适合于对有机物正辛醇-水分配系数进行QSPR建模.  相似文献   

17.
PBDEs的来源特征、环境分布及污染控制   总被引:2,自引:0,他引:2  
多溴联苯醚(Polybrominated diphenyl ethers,PBDEs)生产应用、环境分布与生态风险之间的关系将如何影响我国的未来,具体涉及到工业、环境、健康、人类繁衍等的社会问题.由于PBDEs阻燃效率高,热稳定性好,价格便宜,作为添加剂被广泛应用在电子、电器、化工、交通、建材、纺织、石油等领域的阻燃产品中.PBDEs进入环境后迁移扩散并富集于沉积物和生物体内,进入人体后引起肝脏毒性、内分泌干扰、神经毒性和生育能力下降等而危害人类的健康.基于此,从生产应用、品种生产量、分子的物理化学特性以及毒性等的文献数据分析了PBDEs的来源特征与环境危害,分析这些性质对环境分布与污染控制的基础支持关系;从沉积物、水体、大气、水生生物、人体5个方面考察了PBDEs的环境本底浓度变化、分配关系、迁移规律、时间效应,分析了生产、应用与扩散的多因素影响关系,发现全球性PBDEs污染物蔓延的现象,沉积物是主要的归趋场所,室内空气中的浓度远高于室外,水中浓度较低,水生生物和人体均能富集PBDEs,通过饮食、母乳和呼吸摄入,可实现代际传播,污染的分布呈现介质与区域的不同特征;污染控制需要考虑点源技术与面源修复的联合,结合PBDEs的物理性质、分子结构及其化学特性,统计分析了微生物法、光化学降解法和零价铁还原法的原理及其有效性,根据PBDEs在产品中存在与分布的特点,提出收集-分离-富集-超临界催化还原和氧化毁毒的工艺,针对实际环境(以电子垃圾塑料和流域水体及沉积物为对象)中的PBDEs进行回收或处理,结合材料如催化剂的应用,从动力学和热力学方面提高PBDEs无害化的效率.最后,从生产管理、环境监测、风险评价、技术集成等方面提出了未来的努力方向.  相似文献   

18.
To more reasonably evaluate human intake of PBDEs via dust ingestion, bioaccessibility should be taken into account. Previously, we developed an in vitro method to determine the bioaccessibility of PBDEs in food. Here, this method was adapted to determine the bioaccessibility of PBDEs in dust and the digestion conditions that influenced the bioaccessibility of PBDEs were optimized. The digestion conditions included the incubation time of dust in the intestinal digestion solution (T), the bile concentration in the intestinal digestion solution (Cbile), and the ratio of the volume of the intestinal digestion solution to dust (R). The influence of the concentrations of individual PBDE congeners (CPBDE) on the bioaccessibility of PBDEs was also investigated. Central composite design was used to build an experimental model and set experimental parameters, and response surface methodology was used to analyze the obtained data. The results showed that the bioaccessibility of PBDEs increased with the increases of Cbile and R, and was independent of T and CPBDE. Under the digestion conditions with Cbile and R being at 4.0-7.0 g/L and 150-250, respectively, the bioaccessibility of PBDEs in the method-dust varied from 39.2% to 72.8%, which were comparable with the bioaccessibility or bioavailability of PBDEs in dust/soil in the literature. Thus, the in vitro method to measure the bioaccessibility of PBDEs in dust was established and validated. Finally, the bioaccessibility of PBDEs in four natural dust samples, which ranged from 36.1% to 43.3%, were determined using the adapted method.  相似文献   

19.
邻苯二甲酸酯类化合物正辛醇-水分配系数的QSPR研究   总被引:4,自引:3,他引:1  
隆兴兴  牛军峰  史姝琼 《环境科学》2006,27(11):2318-2322
采用PM3算法计算邻苯二甲酸酯类化合物(PAEs)的量子化学参数,应用偏最小二乘(PLS)算法建立了PAEs的正辛醇-水分配系数(KOW)的定量结构-性质相关(QSPR)模型.模型的结果表明,用量子化学参数建立的QSPR模型相关性显著,具有较好的稳健性和预测能力,因此,利用该模型可对其他PAEs分子的lgKOW值进行初步预测.模型的结果表明,影响lgKOW的主要量子化学参数是分子总能量TE、相对分子质量Mr、平均分子极化率α和分子生成热ΔHf.lgKOW随着Mrα的增大而增大,随着TE和ΔHf的增大而减小.  相似文献   

20.
Accelerated industrialization and urbanization, and unregulated disposal of waste of electric and electronic equipment (e-waste) in China have caused environmental pollution of brominated flame retardants (BFRs). This review summarized the levels, trends, and bioaccumulation characteristics of polybrominated diphenyl ethers (PBDEs) and other potential alternative BFRs including hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-dibromophenoxy) ethane (BTBPE) and decabromodiphenylethane (DBDPE) in wildlife from China. PBDE levels in wildlife from China were generally higher than those from other parts in Asia, and were comparable to those from Europe but were lower than those from North America. However, wildlife from the e-waste recycling sites in South China and East China contained much higher PBDEs compared to other reports around the world, suggesting the heavy contamination of PBDEs in these regions. The alternative BFRs were also detected in wildlife, revealing that the animals are exposed to these chemicals, in addition to PBDEs. Temporal trends indicated by levels in marine mammals from South China suggested that PBDE levels increased from the beginning of 1990s to 2000s, but decreased from the middle of 2000s, followed by relatively steady levels. In contrast, HBCDs were found to be continuously increasing from 1997 to 2007, indicating the increasing usage of HBCDs in China in recent years. Compared to PBDE profiles found in other parts, aquatic species and birds from China contained relatively higher contributions of BDE-28 and 209, respectively, suggesting the possible different usage pattern of PBDEs. Future works including keeping monitoring at a reasonable scale and frequency to make sure levels near urban centers indicative of population do not increase are needed. Additionally, focus effort on e-waste recycling regions to look for impacts and to determine if regulation/controls are resulting in lower environmental contamination, and incorporation of sentinel species in monitoring efforts are recommended.  相似文献   

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