2020, Vol. 41
多溴二苯醚(polybrominated diphenyl ethers, PBDEs)是全球用量最大的溴代阻燃剂(BFRs)之一[1, 2].近年来, PBDEs主要商用品(五、八和十溴二苯醚)陆续被列入《斯德哥尔摩公约》的持久性有机污染物(POPs)清单[3], 在各类环境介质[4~8]及食物[9]中广泛存在.
PBDEs在我国淡水水体等环境介质中的赋存量较大. Zhou等[10]估算太湖沉积物中PBDEs的总量约30 t, 且同系物以BDE-209为主(>80%). Wang等[11]报道太湖沉积物中PBDEs含量(3.8~347 ng ·g-1, 平均72.8 ng ·g-1)远高于六溴环十二烷(HBCD)和四溴双酚A(TBBPA)等其他BFRs.其中, 太湖梅梁湾和贡湖湾等靠近注入河流的沉积物中PBDEs含量高于其他点位, 表明河流注入是太湖中PBDEs的重要来源.
沉积物中BDE-209可通过改变磷矿化细菌的群落组成[12, 13]和促进碱性磷酸酯酶的活性, 从而减少沉积物中的有机磷, 并增加水体和沉积物中的生物可利用磷[14], 进而改变湖库中磷的生物地球化学循环, 加重湖库的富营养化.BDE-209及其还原脱溴生成的低溴BDE[15~17]等二次污染物对生物体的内分泌、神经、生殖[18, 19]和遗传系统[20, 21]及智力[22]等有潜在的毒害作用.
虽然BDE-209易于脱溴降解[23], 但其在环境介质中彻底降解为完全脱溴产物二苯醚(diphenyl ether, DE)是一个漫长的过程[12, 19, 24, 25].环境介质中的低溴BDE究竟主要来自五溴和八溴二苯醚商用品的直接使用、或是高溴BDE的降解, 另外其贡献率如何, 这些目前尚不清楚, 相关研究也十分缺乏, 直接影响了人们对PBDEs同系物来源的正确认识, 以及对十溴二苯醚商用品环境风险的准确评估.
供水安全是城市经济社会持续发展的基石, 作为至2019年末GDP连续21年全省第一的地级市, 泉州人均水资源量仅为福建全省人均的1/3, 是典型的沿海缺水型城市.泉州地处闽南地区, 该地区总面积仅占福建的1/5, GDP却占福建的1/2.笔者前期的研究发现, 泉州市环境中PBDEs含量在闽南地区最高, 这与其制造等产业发达, 溴代阻燃剂用量较多有关.另一方面, 泉州人口稠密(2019年末常住人口874万, 居全省首位), PBDEs潜在的环境和健康风险值得关注.
山美水库是泉州首要的饮用水源地, 位于泉州市第一大江——晋江上游东溪中段, 是晋江流域唯一集供水、灌溉、防洪、发电和生态等综合利用于一体的大型水利枢纽工程, 流域面积1 023 km2, 总库容6.55亿m3, 担负着晋江下游600多万人口的生活和生产用水[26]. 2018年8月5日, 源自山美水库的水直供金门, 开启了两岸“共饮一江水”的时代[27].近年来, 库区水质随流域社会经济快速发展而明显下降, 总氮等甚至为劣Ⅴ类[26].
现有城市水源水库的报道多集中于库区无机或有机污染物的组成和空间分布等, 且大多为一次采样, 缺乏对水库及入库河流沉积物中典型POPs的时空分异和降解来源及其贡献的研究.就闽南地区而言, 湖库研究多集中于氮磷等生源要素方面, PBDEs等POPs的报道稀少, 且集中于海洋沉积物与海洋生物方面[28], 而与城市供水安全和人体健康息息相关的水源水库中PBDEs时空分异和降解来源的研究尚未见报道.
基于以上讨论, 笔者采集典型城市水源水库——泉州山美水库及入库河流代表性点位的表层沉积物样品, 研究PBDEs的含量、污染程度、空间分布、水文期变化、赋存量、同系物组成及其降解来源的贡献, 以期为城市水源水库中PBDEs的污染治理提供基础资料, 并为水环境中PBDEs同系物的自然降解来源研究提供科学依据.
1 材料与方法 1.1 采样使用GPS定位, 抓斗采样器采集表层沉积物.山美入库河流采集了5个样品(图 1), 时间为2013年9月13日.山美水库采集了26个样品(图 2, 丰水期S8样品损失), 时间分别为2012年7月1日(丰水期)、2012年11月4日(枯水期)和2013年3月9日(平水期).其中, 采样点S1和S2位于入库区, S3和S4位于库尾区, S5、S6和S7位于库中区, S8和S9位于坝前区, 入库区连接入库河流, 库尾区为闭合区域, 紧邻九都镇, 坝前区位于水坝上游.
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图 1 山美入库河流沉积物采样点示意 Fig. 1 Map of sediment sampling sites in the inflowing river of Shanmei Reservoir |
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图 2 山美水库沉积物采样点示意 Fig. 2 Map of sediment sampling sites in Shanmei Reservoir |
沉积物样品采集后装入洁净铝箔袋(马弗炉中450℃, 4 h)中密封, 外套聚乙烯自封袋, 带回实验室置于超低温冰箱(<-70℃)中保存.用冻干机-50℃下72 h冻干后研磨过100目筛, 置于洁净铝箔袋中密封, 外套聚乙烯自封袋密封, 于冰箱中冷冻保存.
1.2 样品预处理与分析 1.2.1 标样与试剂PBDEs标样购自Accustandards (New Haven, CT, USA), 13C12-CB-141、13C12-CB-208和13C12-CB-209购自Cambridge Isotope Laboratories (Andover, MA, USA).所有溶剂为分析纯或更优(上海国药集团化学试剂有限公司), 经全玻璃系统重蒸后使用.
1.2.2 样品预处理和仪器分析样品预处理和仪器分析方法基于已有方法修改而来[5, 6].简述如下：四分法分样称取沉积物样品10 g, 用抽提过的洁净滤纸包好, 烧瓶中加入预先活化的铜片和200 mL丙酮/正己烷(1 :1)索氏抽提, 抽提液旋蒸浓缩后, 置换溶剂为正己烷, 过多层硅胶/氧化铝柱净化, 用70 mL二氯甲烷/正己烷(1 :1)淋洗, 淋洗液旋蒸浓缩后转入1.5 mL棕色玻璃瓶中, 氮吹置换溶剂为正己烷, 定容至50 μL.样品进样前加入适量13C12-CB-208内标, 用安捷伦GC-MS(Agilent 7890N GC/5975 MS)负化学电离(NCI)选择离子扫描(SIM)法测定PBDEs的组成.扫描离子3~7溴BDE为79和81, 8~9溴BDE为79、81、408.7±2、486.7和488.7, BDE-209为79、81、486.7和488.7.内标13C12-CB-208为475.8±2.回收率指示物13C12-CB-141和13C12-CB-209分别为371.9±2和509.7±2.目标化合物为BDE-17、BDE-28、BDE-71、BDE-47、BDE-66、BDE-77、BDE-100、BDE-99、BDE-85、BDE-118、BDE-154、BDE-153、BDE-138、BDE-183、BDE-190、BDE-197、BDE-203、BDE-196、BDE-208、BDE-207、BDE-206和BDE-209, 共22种.内标法五点校正曲线定量.仪器检测限(IDL)用约5倍信噪比(S/N)的标样连续测定6~8次, 取其标准差的3.36倍作为IDL, 3~7溴BDE为0.41~0.75 pg, BDE-209为3.74 pg.空白样品中只有少量的BDE-47被检出, 含量小于大多数样品的5%.流程空白加标回收率3~7溴BDE为105.0%±4.7%, BDE-209为86.8%±17.1%;基质空白加标回收率3~7溴BDE为103.1%±5.1%, BDE-209为70.7%±1.7%.回收率指示物13C12-CB-141、13C12-CB-209的回收率分别为106.3%±16.3%和97.4%±13.4%.数据未经回收率校正.
2 结果与讨论 2.1 沉积物中PBDEs的含量和污染程度入库河流和山美水库沉积物中BDE-209中值含量(1 067.2 ng ·g-1, 155.9 ng ·g-1)均比Σ21PBDEs(4.92 ng ·g-1, 3.15 ng ·g-1, 除BDE-209外的21种BDE含量之和)高2~3个数量级, 表明山美水库流域的PBDEs以BDE-209为主.入库河流沉积物中ΣPBDEs(22种BDE含量之和, 含BDE-209)中值含量(1 072.1 ng ·g-1, 均值1 406.7 ng ·g-1)是山美水库中值(160.4 ng ·g-1, 均值267.7 ng ·g-1)的6.7倍, 显示入库河流是山美水库的主污染源.
注入湖库的河流因河床侵蚀和接纳各种污染排放, 通常是湖库中PBDEs等POPs的首要污染源[29].入巢湖河流沉积物中BDE-209中值含量(12.4 ng ·g-1[30])是巢湖沉积物(2.5 ng ·g-1[31])的5.0倍(图 3).流经保定市区的府河沉积物中BDE-209含量算数均值(102.6 ng ·g-1, 未报道中值, 下同)是其注入的白洋淀(10.4 ng ·g-1)的9.9倍[32].韩国入Shihwa湖城市溪流中ΣPBDEs(2 180 ng ·g-1)是Shihwa湖近岸(25 ng ·g-1)的87.2倍, 离岸(1.8 ng ·g-1)的1 211.1倍[33].意大利入湖河流沉积物中BDE-209的含量(67.0 ng ·g-1)是Maggiore湖(12.1 ng ·g-1)的5.5倍[34].Melymuk等[35]报道城市河流输入和污水处理厂排放是安大略湖中PBDEs的两个主要来源, 其输入贡献率(>85%)远高于大气干湿沉降途径.
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ΣnPBDEs<表示除BDE-209外测定的其他BDE同系物总和, 横坐标括号中数字(i/j)表示样本量/BDE同系物数量,参考线表示山美水库(实线)及入库河流(虚线)Σ21PBDEs或BDE-209算数均值 图 3 山美水库及入库河流表层沉积物中PBDEs的含量与国内外其他地点的比较 Fig. 3 Comparisons of the contents of PBDEs in the surface sediments of Shanmei Reservoir and its inflowing river,Quanzhou, China with other sites at home and abroad |
与国内外研究相比(图 3), 山美水库及入库河流表层沉积物中PBDEs的污染程度较国内外大多数湖库[7, 10, 11, 31~34, 36~46]与河流[30, 32~34, 36, 47~54]更严重, 且主要体现为BDE-209的污染较重, 表明山美水库PBDEs污染程度较高, 流域内商用十溴二苯醚的用量较多.
2.2 PBDEs的空间分布山美水库及入库河流每个样点22种BDE的含量经多种检验(Kolmogorov-Smirnov、Shapiro-Wilk、Anderson-Darling和D'Agostino-K squared test)均不符合正态分布, 但符合对数正态分布, 因此以下采用不基于正态分布前提非参数的Spearman相关系数讨论.
河流各样点间BDE同系物呈极显著高度正相关(r为0.953~1, P<0.000), 表明河流各样点PBDEs的组成高度相似, 来源相同.H1和H2位于上游来水口(图 1), 水流在此处变缓, 污染物易于沉积,ΣPBDEs含量最高(2 422.5 ng ·g-1和2 329.3 ng ·g-1, 图 4).H4因下游河道转弯变窄而水流减缓, 且H4(水深15 m)较H3(水深10 m)地势低, 污染物易沉积汇集, 致H4(1 072.1 ng ·g-1)高于H3(409.2 ng ·g-1).H5水流因河道变窄而加快, 底泥可能被搅动悬浮于水体中, 且H5水深(14 m)比H4略浅, 其ΣPBDEs(800.5 ng ·g-1)略低于H4.上游样点(H1和H2)ΣPBDEs是下游(H4和H5)的2.5倍, 显示PBDEs在从河流上游到下游的过程中逐渐沉积.
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图 4 山美入库河流表层沉积物中PBDEs的空间分布 Fig. 4 Spatial distributions of PBDEs in the inflowing river surface sediments of Shanmei Reservoir |
山美水库各水文期ΣPBDEs的空间分布见图 5.除丰水期S1和S3(r=0.493, P=0.062)、枯水期S2和S9(r=0.507, P=0.054)及平水期S5和S7(r=0.420, P=0.175)BDE同系物含量间Spearman相关系数不显著外, 其他点位间均显著相关(r为0.564~0.994, P<0.034), 显示库区大多数样点的PBDEs组成相似度较高, 有共同的主要来源.
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图 5 山美水库表层沉积物中ΣPBDEs的时空分异 Fig. 5 Spatiotemporal differentiation of ΣPBDEs in surface sediments of Shanmei Reservoir |
丰水期ΣPBDEs算数均值含量入库区(538.2 ng ·g-1)>库中区(192.7 ng ·g-1)>库尾区(104.5 ng ·g-1)>坝前区(27.5 ng ·g-1).入库区与入库河流样点间相关系数在水库各功能区中最高(r为0.915~0.964, P<0.000), 结合前文入库河流ΣPBDEs远高于库区的情况, 显示入库区PBDEs直接来自入库河流.丰水期正值汛期, 地处亚热带沿海区域的泉州台风暴雨高发, 上游来水丰富(河流平均透明度：134 cm), 携带大量颗粒物(水库平均透明度, 丰：152 cm, 枯：230 cm)进入库区后水域面积扩大, 水流减缓, 悬浮颗粒易在入库区沉积, 致其ΣPBDEs最高; 库中区位于入库区下游, 受入库河流影响较小(r为0.690~0.903, P≤0.017), ΣPBDEs低于入库区; 库尾和坝前区受上游来水影响最小, 但库尾区受附近九都镇人类活动影响明显, 使库尾近岸的S3与入库区S1相关性不显著; 坝前区丰水期排水增加, 部分底泥随水流排出, ΣPBDEs最低.
枯水期ΣPBDEs入库(378.1 ng ·g-1)>库尾(166.4 ng ·g-1)>坝前(165.3 ng ·g-1)>库中(77.6 ng ·g-1).枯水期上游来水最少, 但入库区ΣPBDEs仍最高, 入库区和入库河流样点间相关系数在各功能区中也最高(r为0.779~0.915, P<0.005), 与丰水期一致, 偏高, 显示枯水期九都镇对库尾区影响较大; 库中区低于坝前区, 与枯水期大坝排水少有关; S9与入库区样点相关系数较低或不显著(r为0.507~0.654, P为0.008~0.054), 且坝前区与入库河流相关系数在各功能区中最低(r为0.314~0.903, P≤0.346), 均显示枯水期因来水少, 坝前区ΣPBDEs受来水影响程度减弱.
平水期ΣPBDEs库中(607.3 ng ·g-1)>入库(498.0 ng ·g-1)>坝前(175.1 ng ·g-1)>库尾(123.8 ng ·g-1).平水期水位稳定, 库中区ΣPBDEs最高受S7附近从枯水期后开始鱼类养殖的影响, 鱼体内易富集大量的PBDEs, 其活动可能造成S7偏高[55], S7和库中区S5、S6及库尾区S3的相关系数不显著或较低(r为0.420~0.622, P为0.018~0.175), 也显示其受到了局地污染源的影响; 入库区高于库尾区, 且入库区与入库河流相关系数在各功能区中仍最高(r为0.779~0.964, P<0.005), 而库尾区与入库河流相关系数则最低(r为0.454~0.882, P≤0.128), 表明上游来水仍是水库的主污染源.
综上, 除平水期S7外, 各水文期入库区ΣPBDEs均最高, 入库区和入库河流样点间BDE含量显著正相关(r为0.779~0.964, P<0.005)且在各功能区中相关性最强, 显示入库河流是山美水库PBDEs的主污染源; 库尾区近九都镇的S3各水文期ΣPBDEs均高于S4(1.7~3.6倍), 且库尾区与入库河流相关性较低, 显示库尾区受城镇影响较大; 坝前区近坝的S9受排水及大坝拦截作用使沉积物被带走或悬浮于水体中, 其ΣPBDEs低于S8.样点间ΣPBDEs含量不同且差别较大, 显示各样点污染源及影响因素有所不同[10].
除入库区个别低溴BDE的丰度略小于入库河流外(水库/河流：~0.8), 山美水库各功能区Tri~Nona-BDE的平均丰度均高于入库河流, 其年均比值为3.3~147.8, 表明PBDEs在水库中发生了逐级还原脱溴自然降解, 且各级还原脱溴速率存在差异[24, 56], 部分BDE因继续还原脱溴速率较慢而累积.山美水库各功能区BDE-209的丰度均小于入库河流(99.4%), 且入库区BDE-209丰度最高(丰：99.0%, 枯：98.7%, 平：98.9%), 库中区最低(丰：94.4%, 枯：93.2%, 平：96.6%), 显示PBDEs在从入库河流进入水库再到库中区的过程中自然降解程度逐渐加深.
2.3 PBDEs的水文期变化各水文期ΣPBDEs的Pearson相关系数不显著, 但丰水期和枯水期呈近显著正相关(r=0.699, P=0.054).尽管各水文期ΣPBDEs经Kolmogorov-Smirnov检验符合正态分布, 但多种更严格的正态检验方法(Shapiro-Wilk、Anderson-Darling和D'Agostino-K squared test)显示, 枯水期ΣPBDEs不符合正态分布(P<0.013), 且丰水期正态检验的相伴概率也较低(P为0.083~0.251).因此, 进一步通过Spearman相关系数分析显示, 丰水与其他水文期均显著正相关(均为r=0.714, P=0.047), 而枯水和平水期近显著正相关(r=0.617, P=0.077), 表明各样点ΣPBDEs的水文期变化较一致, 水文期变化对沉积物中ΣPBDEs含量有一定的影响.
由于部分水文期ΣPBDEs不符合正态分布, 但均符合对数正态分布(P=1, K-S test), 故经对数转换后作双因素方差分析(Two-Way ANOVA)显示, 水文期变化对ΣPBDEs的影响统计不显著(P=0.178), 而采样点位变化则对ΣPBDEs有极显著影响(P=0.000 1), 表明水库沉积物中ΣPBDEs的空间分布变异大于水文期变化.基于Fisher最小显著差异法(LSD)的多重比较(multiple comparisons)进一步显示, S5与其他所有样点均有显著差异, 表明S5沉积情况与其他点位显著不同.S5地势最高, 沉积物以砂质为主, 沉积柱采样长度仅为其他样点平均长度的57% ~67%, ΣPBDEs在所有样点中也最低, 且低溴BDE的比例与其他点位有较大差异(见2.5节).入库区和其他水库功能区之间有(近)显著差异(P为0.019~0.061), 结合前文入库区ΣPBDEs最高的情况, 显示入库区因接纳了入库河流悬浮颗粒的大量沉积, ΣPBDEs(近)显著高于其他距来水较远的功能区.
不同水文期库区ΣPBDEs空间分布的影响因素存在差异.丰水期ΣPBDEs在各功能区的分布主要受上游来水的影响; 枯水期地下水上涌可能会使下层沉积物中污染物重新进入表层, 加之九都镇的人为活动, 使库尾区枯水期ΣPBDEs高; 平水期除受九都镇影响较大的S3外, 其他点位ΣPBDEs高于枯水期, 除上游来水因素外, 平水期库区水体pH(均值8.3, 范围7.9~8.6)较枯水期(均值7.5, 范围7.3~7.7)更偏碱性可能也有一定影响, 因为碱性条件更有利于沉积物中有机质被矿物质吸附.
各样点ΣPBDEs的水文期变化也有差异.S1和S2处ΣPBDEs算数均值丰>平>枯, 与上游来水量一致.S3枯>丰>平, 枯水期最高显示其主要受九都镇的影响.S4枯平相当, 丰水期最低, 说明库尾城镇对S4的影响大于上游来水.S5各水文期ΣPBDEs均最低且变化较小, 与S5地势最高(水深20 m)且该处沉积物砂质为主的质地有关.S6丰水期最高, 与其地势低(水深35 m), 底泥易在此汇集有关.S7平水期最高, 与附近在枯水期后的鱼类养殖有关[55].S8平枯相当, 可能是枯水和平水期水流缓慢, 大坝排水较少所致.S9与S8类似, 枯平相当, 而丰水期最低, 与丰水期排水较频繁, 颗粒物来不及沉降就排出水库, 以及排水扰动底泥再悬浮, 随排水去除有关.
2.4 PBDEs的赋存量沉积物既是PBDEs的重要储库, 也是水环境中PBDEs的二次释放源.虽然高溴BDE尤其是BDE-209因Kow大, 理论上应以固相赋存为主, 但研究者在英国亚耳河水(17~295 ng ·L-1)和北美五大湖水中监测到大量的BDE-209(丰度18%±3%), 因为PBDEs能以胶体态存在于水中, 且其在胶体中的分配比例随溴代数增加而提高[19].
为评估山美水库沉积物作为PBDEs源和汇的潜力, 用公式(1)[7]计算其单位面积赋存量：
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(1) |
式中, I为PBDEs的单位面积赋存量(kg ·km-2), k为单位转换常数, Ci为PBDEs的平均含量(ng ·g-1), d为沉积物厚度(20 cm[10]), ρ为沉积物密度(1.5 g ·cm-3[10, 31]).
赋存总量用公式(2)[7]计算：
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(2) |
式中, TI为总赋存量(t), A为山美水库水域面积(23.75 km2[27]).
山美水库沉积物中BDE-209、Σ21PBDEs和ΣPBDEs的单位面积赋存量分别为79.1、1.2和80.3 kg ·km-2, 相应赋存总量分别为1.88、0.03和1.91 t.虽然山美水库中ΣPBDEs赋存总量小于国内的太湖(30 t, 水域面积2 338.1 km2[10])和北美五大湖中的苏必利尔湖、密歇根湖和休伦湖(85.3 t, 水域面积总计199 500 km2[7]), 但其单位面积沉积物中ΣPBDEs的赋存量(80.3 kg ·km-2)却是太湖(12.8 kg ·km-2)的6.3倍, 北美五大湖(0.427 kg ·km-2)的188倍, 表明山美水库PBDEs污染较为严重, 应深入研究其作为城市水源水库潜在的环境和健康风险, 也应及时对其污染源进行管控和治理.
由于山美水库PBDEs等有机污染和氮磷等生源要素污染均以河流输入为主, 且PBDEs等POPs可增加沉积物中磷等生源要素的释放量和生物可利用率[14], 从而加重湖泊的富营养化, 因此, 一方面应管控上游来水河流流域工业点源污染、农业面源污染和居民生活垃圾等外源输入, 另一方面应疏浚污染较重的入库河流等区域的沉积物, 以实现外源管控、内源削减的综合治理.
2.5 PBDEs的同系物组成测定的22种3~10溴BDE按溴代数划分：Tri-BDE包括BDE-17和BDE-28, Tetra-BDE包括BDE-71、BDE-47、BDE-66和BDE-77, Penta-BDE包括BDE-100、BDE-99、BDE-118和BDE-85, Hexa-BDE包括BDE-154、BDE-153和BDE-138, Hepta-BDE包括BDE-183和BDE-190, Octa-BDE包括BDE-197、BDE-203和BDE-196, Nona-BDE包括BDE-208、BDE-207和BDE-206, Deca-BDE为BDE-209.
山美水库沉积物中不同溴代数BDE的组成表明(图 6)：BDE-209丰度最高(中值98.3%, 均值96.9%, 范围84.5% ~99.2%), 这与国内主要湖库沉积物以BDE-209为主的PBDEs组成一致[10, 11, 31, 32, 36, 39, 40].各水文期S5的Deca-BDE丰度均最小(84.5% ~92.0%), 而Nona-BDE(3.2% ~5.7%)、Penta-BDE(3.5% ~4.8%)和Tetra-BDE(0.4% ~1.6%)则最高, 可能是该处沉积物以砂质为主, 且地势在水库各样点中最高, 水体中溶解氧(DO)也最高(8.1 mg ·L-1, 水库各样点范围：6.1~8.1 mg ·L-1), Deca-BDE较易降解为低溴BDE.
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图 6 山美水库沉积物中各溴代数BDE的组成 Fig. 6 Compositions of BDE with different brominated levels in the sediments of Shanmei Reservoir |
Nona-BDE丰度(中值1.2%, 均值1.6%, 范围0.6% ~5.7%)仅次于Deca-BDE, Octa-BDE丰度中值为0.1%(均值0.2%, 范围0~2%), 而Tri~Hepta-BDE合计丰度中值仅0.4%(均值1.3%, 范围0.2% ~8.0%).商用十溴二苯醚Saytex 102E和Bromkal 82-0DE主要同系物丰度为BDE-209(96.8%和91.6%)、BDE-206(2.19%和5.13%)和BDE-207(0.24%和4.10%)等[57], 相应的BDE-209 :BDE-206 :BDE-207分别为：403 :9 :1和22 :1 :1, 山美水库沉积物中该比值(173 :1 :1)介于以上两者之间, 且这些同系物在所有样品中均为主要同系物, 说明山美水库流域使用了十溴二苯醚商用品. BDE-208在商用PBDEs中丰度均很低(<0.02% ~0.19%), 而在山美水库沉积物中丰度(中值0.31%, 均值0.43%, GM 0.37%, 范围0.16% ~1.34%)则较高, 表明其主要来自十溴二苯醚的还原脱溴降解.山美水库沉积物中BDE-208(0.43%)和BDE-197(0.12%)均值丰度都高于商用十溴二苯醚Saytex 102E和Bromkal 82-0DE(BDE-208：0.06%和0.07%, BDE-197：0和0.03%), 而BDE-206(0.60%)则低于商用十溴二苯醚(2.19%和5.13%)[57], 表明沉积物中的Deca-BDE先脱溴还原为Nona-BDE, 随后继续还原为Octa-BDE.
山美水库不同溴代数BDE及ΣPBDEs含量之间的Spearman相关系数显示(表 1), 各水文期ΣPBDEs与Deca-BDE极显著完全正相关(r=1), 进一步说明BDE-209是山美水库沉积物中首要的PBDEs同系物; 各水文期Deca-BDE与Nona-BDE间均极显著高度正相关(r为0.905~1.0, P≤0.002), 说明两者有共同的来源且环境行为一致[10]; 各水文期Octa-BDE和Hepta-BDE间(近)显著中度正相关(r为0.619~0.750, P<0.102), 说明两者有部分共同来源.其中, Octa-BDE来自十溴二苯醚商用品[57]及其逐级还原脱溴降解, 而Hepta- BDE则可能主要来自Octa-BDE的继续还原脱溴降解[19, 25].
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表 1 山美水库各水文期不同溴代数BDE含量的Spearman相关系数1) Table 1 Spearman correlations for contents of BDE with different brominated levels in various hydrological periods of Shanmei Reservoir |
此外, 丰水期Hepta-BDE和Penta-BDE间(r=0.810, P=0.015), 枯水期Penta-BDE和Tetra-BDE间(r=0.783, P=0.013), 丰水期Penta-BDE和Tri-BDE间(r=0.833, P=0.010), 枯水和平水期Tetra-BDE和Tri-BDE间(r为0.700~0.717, P<0.036)也显著中度正相关, 丰水和平水期高溴BDE(Deca-BDE和Nona-BDE)与低溴BDE(Tetra-BDE和/或Tri-BDE)显著中高度正相关(r为0.683~0.950, P<0.047), 进一步说明高溴BDE逐级还原脱溴是山美水库沉积物中低溴BDE的重要来源.
2.6 PBDEs同系物的降解来源分析商用五溴二苯醚DE-71和Bromkal 70-5DE中主要同系物丰度为BDE-99(48.60%和44.80%)、BDE-47(38.20%和42.80%)、BDE-100(13.10%和7.82%)、BDE-153(5.44%和5.32%)和BDE-154(4.54%和2.68%)等[57], 相应地BDE-99 :BDE-47 :BDE-100 :BDE-153 :BDE-154分别为11 :8 :3 :1 :1和17 :16 :3 :2 :1, 山美水库沉积物中该比值(0.2 :0.7 :0.1 :0.2 :1)较其低1~2个数量级, 表明这些低溴BDE并非来自商用五溴二苯醚.商用八溴二苯醚DE-79和Bromkal 79-8DE中主要同系物丰度为BDE-183(42.00%和12.60%)、BDE-197(22.20%和10.50%)、BDE-207(11.50%和11.20%)、BDE-196(10.50%和3.12%)、BDE-153(8.66%和0.15%)、BDE-203(4.40%和8.14%)、BDE-206(1.38%和7.66%)和BDE-209(1.31%和49.60%)等[57], 相应的BDE-183 :BDE-197 :BDE-207 :BDE-196 :BDE-153 :BDE-203 :BDE-206 :BDE-209分别为：30 :16 :8 :8 :6 :3 :1 :1和1.6 :1.4 :1.5 :0.4 :0.02 :1 :1 :6.5, 水库沉积物中该比值(0.2 :0.2 :0.9 :0.1 :0.05 :0.05 :1 :162)较其大多相差1~2个数量级, 表明这些BDE并非来自商用八溴二苯醚.综上, 山美水库表层沉积物中低溴BDE主要来自商用十溴二苯醚的逐级还原脱溴自然降解.
山美水库表层沉积物和主要PBDEs商用品中BDE同系物丰度比值对照见表 2.其中, Rs表示样品中不同BDE丰度比值, Rc表示商用品中相应BDE丰度比值, R(m/n)=Rs/Rc(m/n表示特定BDE相比).R(m/n)=1表示样品中BDE丰度比值与商用品一致, 该BDE主要来自商用品使用; R(m/n)>1表示样品中BDE丰度比值大于商用品, 表示其可能来自样品中更高溴BDE的降解, 且其继续降解为更低溴BDE的速率较小(除BDE-209外), R(m/n)<1表示样品中BDE丰度比值小于商用品, 表示其可能已发生还原脱溴, 部分降解为更低溴BDE.
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表 2 山美水库沉积物和主要PBDEs商用品中BDE丰度比值对照 Table 2 Comparisons of the BDE abundance ratios in sediments of Shanmei Reservoir and the major commercial products of PBDEs |
R(BDE-209/Nona-BDE)为1.57和6.20, 显示Deca-BDE降解产生的Nona-BDE迅速降解生成更低溴BDE, 这与沉积物中微生物降解BDE-209时, Nona-BDE先增加后又减少波动的报道一致[56].R(BDE-209/BDE-208)为0.14和0.17, 表明BDE-209降解产生了BDE-208; R(BDE-209/BDE-207)为0.43和7.73, R(BDE-209/Nona-BDE)为3.66和9.07, 显示BDE-209降解为BDE-207和BDE-206的速率高于其继续降解为更低溴BDE的速率.R(BDE-207/BDE-197)R(BDE-207/BDE-196), 显示BDE-207降解为BDE-197(间位脱溴)的速率高于其降解为BDE-196(邻位脱溴).据报道[58], 商用八溴二苯醚降解时, 邻、间、对位溴原子的取代率分别为24%、73%和54%, 其中, 间位溴原子取代率最高, 因为其空间位置比邻位溴原子离醚键远, 空间位阻较小, 故该处重叠的电子云斥力较小, 溴原子更易被氢原子取代.另外, PBDEs间位溴原子数量约是对位的2倍, 故降解过程中, 间位最易被取代, 对位次之, 邻位最难被取代.R(BDE-197/BDE-183)<R(BDE-196/BDE-183), 因为BDE-196可通过间位脱溴降解为BDE-183, 而BDE-197还可通过间位脱溴还原为BDE-184[58, 59].R(BDE-196/BDE-183)>1, 显示BDE-183没有出现累积, 因为其易于间位脱溴继续降解产生BDE-154[58].以商用五溴二苯醚Rc为分母, R(BDE-183/BDE-154)为40.5和7.3, 而以商用八溴二苯醚Rc为分母, R(BDE-183/BDE-154)为0.02和0.003, 两者差异大的原因可能是五溴二苯醚中BDE-183和BDE-154均非主要同系物, 且八溴二苯醚中BDE-154非主要同系物[57], 这需要继续研究.R(BDE-138/BDE-85)为0.14和0.15, 显示BDE-138较快降解为BDE-85.R(BDE-154/BDE-99)为49.3和77.0, R(BDE-153/BDE-99)为7.3和6.9, 结合R(BDE-196/BDE-183)和R(BDE-99/BDE-47), 说明BDE-154和BDE-153出现累积, 较少降解为BDE-99(邻位脱溴[58]).R(BDE-99/BDE-47)为0.24和0.29, 说明BDE-99较多降解为BDE-47(间位脱溴[60]), 可能系微生物还原脱溴所致[56].R(BDE-47/BDE-28)为0.034和0.012, R(BDE-47/BDE-17)为0.004和0.003, 显示BDE-47降解产生了BDE-28和BDE-17, 且BDE-47降解为BDE-28(邻位脱溴)的速率低于其降解为BDE-17(对位脱溴)的速率, 与理论研究一致[58, 61].
根据降解途径中样品和商用品BDE丰度比值(表 2), 选择主要同系物, 分析山美水库沉积物中不同溴代数BDE的降解率.Deca-BDE →Nona-BDE：BDE-209降解为BDE-207和BDE-206是主要途径[59], 同商用十溴二苯醚相比, R(BDE-209/BDE-207)为0.43和7.73, R(BDE-209/Nona-BDE)为3.66和9.07, 显示Nona-BDE丰度较低, 说明Nona-BDE可较快继续降解为低溴BDE.R(BDE-209/BDE-208)为0.14和0.17, 显示BDE-208约83% ~86%源自BDE-209的降解.Nona-BDE→Octa-BDE：R(BDE-207/BDE-197)为0.04, R(BDE-207/BDE-196)为0.78, BDE-207更易降解为BDE-197[58].R(BDE-206/BDE-196)为0.67, R(BDE-206/BDE-203)为0.26, BDE-206更易降解为BDE-203, 所以BDE-207→BDE-197(降解率约96%)和BDE-206→BDE-203(降解率约74%)为Nona-BDE降解至Octa-BDE的主 要 途 径. Octa-BDE→Hepta-BDE：R[(BDE-197+BDE-196)/BDE-183]为1.9和1.3, 说明Octa-BDE降解至Hepta-BDE过程较慢, 使Octa-BDE累积.Hepta-BDE→Hexa-BDE：BDE-183降解为BDE-154、BDE-153和BDE-138为主要途径[59, 62].以商用八溴二苯醚Rc为分母, R(Hepta-BDE/Hexa-BDE)为0.003~1.0, 而以商用五溴二苯醚Rc为分母, R(Hepta-BDE/Hexa-BDE)为7.3~273.1, 两者矛盾的原因可能是商用五溴二苯醚中BDE-183、BDE-154和BDE-138丰度很小, 且商用八溴二苯醚中BDE-154和BDE-138丰度很小[57], 以及样品中BDE-153和BDE-138丰度小.Hexa-BDE→Penta-BDE：BDE-138→BDE-85和BDE-154、BDE-153→BDE-99为主要途径.R(BDE-138/BDE-85)为0.14和0.15, 显示其降解率约85%, 而BDE-154和BDE-153→BDE-99的R(m/n)为6.9~77.0, 显示其降解速度较慢, 使BDE-154和BDE-153累积.Penta-BDE→Tetra-BDE：BDE-99 BDE-47为主要途径.R(BDE-99/BDE-47)为0.24和0.29, 显示BDE-99→BDE-47降解率大致在71% ~76%之间.Tetra-BDE Tri-BDE：BDE-47→BDE-28 和 BDE-17 为 主 要 途 径, R[BDE-47/(BDE-28+BDE-17)]为0.006和0.014, 说明Tetra-BDE至Tri-BDE降解率约99%.
山美入库河流表层沉积物和主要PBDEs商用品中BDE丰度比值对照见表 3.相比山美水库, Deca~Penta-BDE的R(m/n)同水库类似, 大部分>1且大于水库, 而Penta~Tri-BDE值<1, 且小于水库, 可能是入库河流水流湍急, 水环境不稳定, Deca-BDE降解较库区少所致.
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表 3 山美入库河流沉积物和主要PBDEs商用品中BDE丰度比值对照 Table 3 Comparisons of the BDE abundance ratios in the inflowing river sediments of Shanmei Reservoir and the major commercial products of PBDEs |
淡水湖库是我国众多城市的主水源, PBDEs尤其是BDE-209在我国多区域历史用量和环境赋存量大, 其自然降解过程复杂漫长, 一系列毒性更大的低溴BDE产物给水环境和人体健康带来风险, 并可能对磷等生源要素的生物地球化学循环产生影响, 进而对湖库环境构成更大的威胁.本研究表明, 我国部分城市水源水库PBDEs污染程度可能较高, 河流注入是首要污染源, PBDEs在水库沉积物中的空间分布变异大于水文期变化, PBDEs自然降解从河流到入库区再到库中区逐渐增加, 且各级还原脱溴速率不同, 部分BDE因继续降解速率较慢而累积, 应继续研究和评估其环境和健康风险, 并通过外源管控和内源削减等综合措施治理改善, 保障城市供水安全.
3 结论(1) 入库河流沉积物中ΣPBDEs中值(1 072.1 ng ·g-1)是山美水库(160.4 ng ·g-1)的6.7倍, 山美水库单位面积沉积物中ΣPBDEs赋存量(80.3 kg ·km-2)是太湖的6.3倍, 北美五大湖的188倍, 其污染程度较国内外大多数湖库更严重, 且以BDE-209为主(中值98.3%, 均值96.9%, 范围84.5% ~99.2%).
(2) 水库大多数样点(r为0.564~0.994, P 0.034)及河流各样点(r为0.953~1, P 0.000)间BDE同系物呈(极)显著中至高度正相关, 显示各样点PBDEs组成相似度较高, 有共同主要来源.入库区和入库河流样点间极显著正相关(r为0.779~0.964, P 0.005)且相关性强于其他功能区, 显示入库河流是水库PBDEs的主污染源.
(3) 各样点ΣPBDEs水文期变化较一致(r为0.617~0.714, P≤0.077), 显示水文期变化对沉积物ΣPBDEs有一定影响, 但统计不显著(P=0.178, Two-Way ANOVA), 而点位变化对ΣPBDEs则有极显著影响(P=0.0001), 表明PBDEs在水库沉积物中的空间分布变异大于水文期变化.
(4) PBDEs自然降解从河流到入库区再到库中区逐渐增加, 且各级还原脱溴速率不同, 部分BDE因脱溴速率较慢而累积.入库区和其他功能区有(近)显著差异(P为0.019~0.061, Two-Way ANOVA, LSD).库尾区近九都镇S3各水期ΣPBDEs均比S4高(1.7~3.6倍), 且库尾区与入库河流相关性较低(r为0.454~0.915, P≤0.128), 显示其受九都镇影响较大.
(5) 丰度比值法研究表明, 低溴BDE主要源自十溴二苯醚的逐级还原脱溴自然降解.Deca-BDE降解产生的Nona-BDE约70%以上可较快继续降解生成Octa-BDE, BDE-208约85%源自BDE-209的降解, 从Octa-BDE到Penta-BDE的降解过程中, 部分Octa-BDE和Hexa-BDE同系物因降解相对较慢而累积, Penta-BDE到Tri-BDE的降解率在70%以上.
| [1] | Li D S, Suh S. Health risks of chemicals in consumer products:a review[J]. Environment International, 2019, 123: 580-587. DOI:10.1016/j.envint.2018.12.033 |
| [2] | Cao Z G, Chen Q Y, Li X X, et al. The non-negligible environmental risk of recycling halogenated flame retardants associated with plastic regeneration in China[J]. Science of the Total Environment, 2019, 646: 1090-1096. DOI:10.1016/j.scitotenv.2018.07.373 |
| [3] | Estill C F, Slone J, Mayer A, et al. Worker exposure to flame retardants in manufacturing, construction and service industries[J]. Environment International, 2020, 135: 105349. DOI:10.1016/j.envint.2019.105349 |
| [4] | Trinh M M, Tsai C L, Chang M B. Characterization of polybrominated diphenyl ethers (PBDEs) in various aqueous samples in Taiwan[J]. Science of the Total Environment, 2019, 649: 388-395. DOI:10.1016/j.scitotenv.2018.08.204 |
| [5] |
韩文亮, 刘豫, 陈海明, 等. 厦门室内多溴二苯醚的沉降通量、季节变化与人体暴露水平[J]. 环境科学, 2016, 37(3): 834-846. Han W L, Liu Y, Chen H M, et al. Indoor deposition flux, seasonal variations and human exposure levels of polybrominated diphenyl ethers in Xiamen, China[J]. Environmental Science, 2016, 37(3): 834-846. |
| [6] | Han W L, Fan T, Xu B H, et al. Passive sampling of polybrominated diphenyl ethers in indoor and outdoor air in Shanghai, China:seasonal variations, sources, and inhalation exposure[J]. Environmental Science and Pollution Research, 2016, 23(6): 5771-5781. DOI:10.1007/s11356-015-5792-9 |
| [7] | Guo J H, Li Z N, Ranasinghe P, et al. Halogenated flame retardants in sediments from the Upper Laurentian Great Lakes:implications to long-range transport and evidence of long-term transformation[J]. Journal of Hazardous Materials, 2020, 384: 121346. DOI:10.1016/j.jhazmat.2019.121346 |
| [8] | Li C, Yang L L, Shi M W, et al. Persistent organic pollutants in typical lake ecosystems[J]. Ecotoxicology and Environmental Safety, 2019, 180: 668-678. DOI:10.1016/j.ecoenv.2019.05.060 |
| [9] | Cheng B, Peng F J, Liu Q R, et al. Nationwide assessment of persistent halogenated compounds (PHCs) in farmed golden pompano of China[J]. Food Chemistry, 2020, 313: 126135. DOI:10.1016/j.foodchem.2019.126135 |
| [10] | Zhou P, Lin K F, Zhou X Y, et al. Distribution of polybrominated diphenyl ethers in the surface sediments of the Taihu Lake, China[J]. Chemosphere, 2012, 88(11): 1375-1382. DOI:10.1016/j.chemosphere.2012.05.048 |
| [11] | Wang J Z, Jia X W, Gao S T, et al. Levels and distributions of polybrominated diphenyl ethers, hexabromocyclododecane, and tetrabromobisphenol A in sediments from Taihu Lake, China[J]. Environmental Science and Pollution Research, 2016, 23(11): 10361-10370. DOI:10.1007/s11356-015-5511-6 |
| [12] | Zhu X F, Zhong Y, Wang H L, et al. New insights into the anaerobic microbial degradation of decabrominated diphenyl ether (BDE-209) in coastal marine sediments[J]. Environmental Pollution, 2019, 255: 113151. DOI:10.1016/j.envpol.2019.113151 |
| [13] | Yu Y Y, Yin H, Peng H, et al. Biodegradation of decabromodiphenyl ether (BDE-209) using a novel microbial consortium GY1:cells viability, pathway, toxicity assessment, and microbial function prediction[J]. Science of the Total Environment, 2019, 668: 958-965. DOI:10.1016/j.scitotenv.2019.03.078 |
| [14] | Chen J, Gao H, Wang P F, et al. Effects of decabromodiphenyl ether on activity, abundance, and community composition of phosphorus mineralizing bacteria in eutrophic lake sediments[J]. Science of the Total Environment, 2019, 695: 133785. DOI:10.1016/j.scitotenv.2019.133785 |
| [15] | Yu Y Y, Yin H, Peng H, et al. Proteomic mechanism of decabromodiphenyl ether (BDE-209) biodegradation by Microbacterium Y2 and its potential in remediation of BDE-209 contaminated water-sediment system[J]. Journal of Hazardous Materials, 2020, 387: 121708. DOI:10.1016/j.jhazmat.2019.121708 |
| [16] | Wang R, Zhu Z X, Tan S F, et al. Mechanochemical degradation of brominated flame retardants in waste printed circuit boards by ball milling[J]. Journal of Hazardous Materials, 2020, 385: 121509. DOI:10.1016/j.jhazmat.2019.121509 |
| [17] | Fan F Y, Zhao L, Yun Z C, et al. In-situ degradation of polybrominated diphenyl ethers from thermal desorption off-gas over structured Fe-based/γ-Al2O3/Al plate-type catalyst[J]. Journal of Hazardous Materials, 2020, 384: 121251. DOI:10.1016/j.jhazmat.2019.121251 |
| [18] | Li X Y, Zhu Y P, Zhang C H, et al. BDE-209 induces male reproductive toxicity via cell cycle arrest and apoptosis mediated by DNA damage response signaling pathways[J]. Environmental Pollution, 2019, 255: 113097. DOI:10.1016/j.envpol.2019.113097 |
| [19] |
韩文亮, 郑小燕. 十溴二苯醚及其降解产物对浮游生物的毒性[J]. 环境科学学报, 2018, 38(2): 821-828. Han W L, Zheng X Y. Toxicity of decabromodiphenyl ether and its degradation products to plankton[J]. Acta Scientiae Circumstantiae, 2018, 38(2): 821-828. |
| [20] | Alfonso S, Blanc M, Joassard L, et al. Examining multi-and transgenerational behavioral and molecular alterations resulting from parental exposure to an environmental PCB and PBDE mixture[J]. Aquatic Toxicology, 2019, 208: 29-38. DOI:10.1016/j.aquatox.2018.12.021 |
| [21] | Wang S R, Romanak K A, Hendryx M, et al. Association between thyroid function and exposures to brominated and organophosphate flame retardants in rural Central Appalachia[J]. Environmental Science & Technology, 2020, 54(1): 325-334. |
| [22] | Gaylord A, Osborne G, Ghassabian A, et al. Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016:a population-based disease burden and cost analysis[J]. Molecular and Cellular Endocrinology, 2020, 502: 110666. DOI:10.1016/j.mce.2019.110666 |
| [23] | Zhou C L, Pagano J, McGoldrick D J, et al. Legacy polybrominated diphenyl ethers (PBDEs) trends in top predator fish of the Laurentian Great Lakes (GL) from 1979 to 2016:will concentrations continue to decrease?[J]. Environmental Science & Technology, 2019, 53(12): 6650-6659. |
| [24] | Guo S, Zhu L H, Majima T, et al. Reductive debromination of polybrominated diphenyl ethers:dependence on Br number of the Br-rich phenyl ring[J]. Environmental Science & Technology, 2019, 53(8): 4433-4439. |
| [25] |
韩文亮, 陈海明. 蒙脱石搭载纳米Ni-Fe超声降解十溴二苯醚[J]. 化工进展, 2018, 37(1): 350-358. Han W L, Chen H M. Ultrasound enhanced degradation of decabromodiphenyl ether by montmorillonite supported Ni-Fe nanoparticles[J]. Chemical Industry and Engineering Progress, 2018, 37(1): 350-358. |
| [26] |
卢彬彬, 陈莹, 陈兴伟, 等. 基于AnnAGNPS模型的山美水库流域非点源氮控制研究[J]. 亚热带资源与环境学报, 2019, 14(1): 54-61. Lu B B, Chen Y, Chen X W, et al. Treatment on non-point source pollution of nitrogen based on AnnAGNPS model in Shanmei Reservoir basin[J]. Journal of Subtropical Resources and Environment, 2019, 14(1): 54-61. |
| [27] | 人民网. 放心的晋江水智慧的供水厂 福建今天向金门供水[EB/OL]. http://fj.people.com.cn/n2/2018/0805/c181466-31897125.html,2018-08-05. |
| [28] | Zhang Z W, Pei N C, Sun Y X, et al. Halogenated organic pollutants in sediments and organisms from mangrove wetlands of the Jiulong River Estuary, South China[J]. Environmental Research, 2019, 171: 145-152. DOI:10.1016/j.envres.2019.01.028 |
| [29] | Liu C, Zhang L, Fan C X, et al. Temporal occurrence and sources of persistent organic pollutants in suspended particulate matter from the most heavily polluted river mouth of Lake Chaohu, China[J]. Chemosphere, 2017, 174: 39-45. DOI:10.1016/j.chemosphere.2017.01.082 |
| [30] | Li F P, Zhang H P, Meng X Z, et al. Contamination by persistent toxic substances in surface sediment of urban rivers in Chaohu City, China[J]. Journal of Environmental Sciences, 2012, 24(11): 1934-1941. DOI:10.1016/S1001-0742(11)61033-4 |
| [31] | Wang J Z, Liu L Y, Zhang K, et al. Halogenated organic contaminants (HOCs) in sediment from a highly eutrophicated lake, China:occurrence, distribution and mass inventories[J]. Chemosphere, 2012, 89(8): 1003-1008. DOI:10.1016/j.chemosphere.2012.06.069 |
| [32] | Hu G C, Xu Z C, Dai J Y, et al. Distribution of polybrominated diphenyl ethers and decabromodiphenylethane in surface sediments from Fuhe River and Baiyangdian Lake, North China[J]. Journal of Environmental Sciences, 2010, 22(12): 1833-1839. DOI:10.1016/S1001-0742(09)60328-4 |
| [33] | Moon H B, Choi M, Yu J, et al. Contamination and potential sources of polybrominated diphenyl ethers (PBDEs) in water and sediment from the artificial Lake Shihwa, Korea[J]. Chemosphere, 2012, 88(7): 837-843. DOI:10.1016/j.chemosphere.2012.03.091 |
| [34] | Poma G, Roscioli C, Guzzella L. PBDE, HBCD, and novel brominated flame retardant contamination in sediments from Lake Maggiore (northern Italy)[J]. Environmental Monitoring and Assessment, 2014, 186(11): 7683-7692. DOI:10.1007/s10661-014-3959-3 |
| [35] | Melymuk L, Robson M, Csiszar S A, et al. From the city to the lake:loadings of PCBs, PBDEs, PAHs and PCMs from Toronto to Lake Ontario[J]. Environmental Science & Technology, 2014, 48(7): 3732-3741. |
| [36] | Su J, Lu Y Z, Liu Z Y, et al. Distribution of polybrominated diphenyl ethers and HBCD in sediments of the Hunhe River in Northeast China[J]. Environmental Science and Pollution Research, 2015, 22(21): 16781-16790. DOI:10.1007/s11356-015-4779-x |
| [37] |
张嘉雯, 魏健, 吕一凡, 等. 衡水湖沉积物中典型持久性有机污染物污染特征与风险评估[J]. 环境科学, 2020, 41(3): 1357-1367. Zhang J W, Wei J, Lü Y F, et al. Occurrence and ecological risk assessment of typical persistent organic pollutants in Hengshui Lake[J]. Environmental Science, 2020, 41(3): 1357-1367. |
| [38] |
高秋生, 焦立新, 杨柳, 等. 白洋淀典型持久性有机污染物污染特征与风险评估[J]. 环境科学, 2018, 39(4): 1616-1627. Gao Q S, Jiao L X, Yang L, et al. Occurrence and ecological risk assessment of typical persistent organic pollutants in Baiyangdian Lake[J]. Environmental Science, 2018, 39(4): 1616-1627. |
| [39] | Wu F C, Guo J Y, Chang H, et al. Polybrominated diphenyl ethers and decabromodiphenylethane in sediments from twelve lakes in China[J]. Environmental Pollution, 2012, 162: 262-268. DOI:10.1016/j.envpol.2011.11.014 |
| [40] | Zhang W R, Lu Y Z, Gao S T, et al. Determination of polybrominated diphenyl ethers in soils and sediment of Hanfeng Lake, Three Gorges[J]. Journal of Environmental Science and Health, Part A, 2015, 50(13): 1316-1323. DOI:10.1080/10934529.2015.1030288 |
| [41] | Wang Q Q, Li X G, Liu S P, et al. The effect of hydrodynamic forcing on the transport and deposition of polybrominated diphenyl ethers (PBDEs) in Hangzhou Bay[J]. Ecotoxicology and Environmental Safety, 2019, 179: 111-118. DOI:10.1016/j.ecoenv.2019.04.026 |
| [42] | Liu K Y, Qiu Y, Zhou S S, et al. Spatial distribution and congener profiles of polybrominated diphenyl ethers in surface sediment from Sanmen Bay and Xiamen Bay, Southeast China[J]. Bulletin of Environmental Contamination and Toxicology, 2019, 103(4): 597-603. DOI:10.1007/s00128-019-02681-3 |
| [43] | Chai M W, Ding H, Shen X X, et al. Contamination and ecological risk of polybrominated diphenyl ethers (PBDEs) in surface sediments of mangrove wetlands:a nationwide study in China[J]. Environmental Pollution, 2019, 249: 992-1001. DOI:10.1016/j.envpol.2019.02.044 |
| [44] | Song W L, Ford J C, Li A, et al. Polybrominated diphenyl ethers in the sediments of the Great Lakes. 1. Lake superior[J]. Environmental Science & Technology, 2004, 38(12): 3286-3293. |
| [45] | Song W L, Ford J C, Li A, et al. Polybrominated diphenyl ethers in the sediments of the Great Lakes. 3. Lakes ontario and erie[J]. Environmental Science & Technology, 2005, 39(15): 5600-5605. |
| [46] | Song W L, Li A, Ford J C, et al. Polybrominated diphenyl ethers in the sediments of the Great Lakes. 2. Lakes michigan and huron[J]. Environmental Science & Technology, 2005, 39(10): 3474-3479. |
| [47] | Ma X D, Zhang H J, Yao W J, et al. Occurrence and bioaccumulation of polybrominated diphenyl ethers in sediments and paddy ecosystems of Liaohe River Basin, Northeast China[J]. Journal of Environmental Sciences, 2016, 43: 250-256. DOI:10.1016/j.jes.2015.10.016 |
| [48] | Wang X T, Chen L, Wang X K, et al. Occurrence, profiles, and ecological risks of polybrominated diphenyl ethers (PBDEs) in river sediments of Shanghai, China[J]. Chemosphere, 2015, 133: 22-30. DOI:10.1016/j.chemosphere.2015.02.064 |
| [49] | Luo Q, Cai Z W, Wong M H. Polybrominated diphenyl ethers in fish and sediment from river polluted by electronic waste[J]. Science of the Total Environment, 2007, 383(1-3): 115-127. DOI:10.1016/j.scitotenv.2007.05.009 |
| [50] | Mai B X, Chen S J, Luo X J, et al. Distribution of polybrominated diphenyl ethers in sediments of the Pearl River Delta and adjacent South China Sea[J]. Environmental Science & Technology, 2005, 29(10): 3521-3527. |
| [51] | Huang Y D, Zhang D N, Yang Y, et al. Distribution and partitioning of polybrominated diphenyl ethers in sediments from the Pearl River Delta and Guiyu, South China[J]. Environmental Pollution, 2018, 235: 104-112. DOI:10.1016/j.envpol.2017.12.049 |
| [52] | Ilyas M, Sudaryanto A, Setiawan I E, et al. Characterization of polychlorinated biphenyls and brominated flame retardants in sediments from riverine and coastal waters of Surabaya, Indonesia[J]. Marine Pollution Bulletin, 2011, 62(1): 89-98. |
| [53] | Barón E, Santín G, Eljarrat E, et al. Occurrence of classic and emerging halogenated flame retardants in sediment and sludge from Ebro and Llobregat river basins (Spain)[J]. Journal of Hazardous Materials, 2014, 265: 288-295. DOI:10.1016/j.jhazmat.2013.10.069 |
| [54] | Richman L A, Kolic T, MacPherson K, et al. Polybrominated diphenyl ethers in sediment and caged mussels (Elliptio complanata) deployed in the Niagara River[J]. Chemosphere, 2013, 92(7): 778-786. DOI:10.1016/j.chemosphere.2013.04.011 |
| [55] | Gandhi N, Gewurtz S B, Drouillard K G, et al. Polybrominated diphenyl ethers (PBDEs) in Great Lakes fish:levels, patterns, trends and implications for human exposure[J]. Science of the Total Environment, 2017, 576: 907-916. DOI:10.1016/j.scitotenv.2016.10.043 |
| [56] | Demirtepe H, Imamoglu I. Degradation of decabromodiphenyl ether (BDE-209) in microcosms mimicking sediment environment subjected to comparative bioremediation strategies[J]. Journal of Environmental Management, 2019, 233: 120-130. |
| [57] | La Guardia M J, Hale R C, Harvey E. Detailed polybrominated diphenyl ether (PBDE) congener composition of the widely used penta-, octa-, and deca-PBDE technical flame-retardant mixtures[J]. Environmental Science & Technology, 2006, 40(20): 6247-6254. |
| [58] |
杨雨寒, 徐伟伟, 彭思侃, 等. 纳米零价铁降解水中多溴联苯醚(PBDEs)及降解途径研究[J]. 环境科学, 2014, 35(3): 964-971. Yang Y H, Xu W W, Peng S K, et al. Reductive debromination of polybrominated diphenyl ethers in aquifier by nano zero-valent iron:debromination kinetics and pathway[J]. Environmental Science, 2014, 35(3): 964-971. |
| [59] | Xie Y Y, Fang Z Q, Cheng W, et al. Remediation of polybrominated diphenyl ethers in soil using Ni/Fe bimetallic nanoparticles:influencing factors, kinetics and mechanism[J]. Science of the Total Environment, 2014, 485-486: 363-370. DOI:10.1016/j.scitotenv.2014.03.039 |
| [60] | Luo Y L, Luo X J, Ye M X, et al. Species-specific debromination of polybromodiphenyl ethers determined by deiodinase activity in fish[J]. Environmental Pollution, 2019, 246: 710-716. DOI:10.1016/j.envpol.2018.12.089 |
| [61] | Wei X P, Yin H, Peng H, et al. Reductive debromination of decabromodiphenyl ether by iron sulfide-coated nanoscale zerovalent iron:mechanistic insights from Fe(Ⅱ) dissolution and solvent kinetic isotope effects[J]. Environmental Pollution, 2019, 253: 161-170. DOI:10.1016/j.envpol.2019.07.007 |
| [62] | Tan L, Lu S Y, Fang Z Q, et al. Enhanced reductive debromination and subsequent oxidative ring-opening of decabromodiphenyl ether by integrated catalyst of nZVI supported on magnetic Fe3 O4 nanoparticles[J]. Applied Catalysis B:Environmental, 2017, 200: 200-210. DOI:10.1016/j.apcatb.2016.07.005 |