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首页> 外文期刊>Environmental Science & Technology >Spatial Trends and Historical Deposition of Polychlorinated Biphenyls in Canadian Midlatitude and Arctic Lake Sediments
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Spatial Trends and Historical Deposition of Polychlorinated Biphenyls in Canadian Midlatitude and Arctic Lake Sediments

机译：加拿大中纬度和北极湖沉积物中多氯联苯的空间趋势和历史沉积

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A study of PCB concentrations and fluxes in lake sediments was conducted to test the "global fraction-ation" hypothesis that deposition of semivolatile organics will decline while more volatile congeners will be enriched in polar regions. Sediment cores were collected from 11 remote lakes in Canada ranging from 49°N to 82°N and were dated using excess ~(210)Pb and ~(137)Cs. Sediment extracts were analyzed for up to 90 PCB congeners by capillary GC-ECD with confirmation by GC/high-resolution MS. Total PCB (ΣPCB) concentrations in surface slices ranged from 2.4 to 39 ng g~(-1) (dry wt) and showed no latitudinal trend. Fluxes (ng m~(-2) yr~(-1)) and inventories of ΣPCB as well as total tetra- to octachlorobiphenyls declined with increasing north latitude while those for di/trichlorobiphenyls showed no latitudinal trend. The proportion of di/trichloro congeners of ΣPCB also increased significantly with latitude, while total octachlorobiphenyls declined. Maximum ΣPCB concentrations were observed in subsurface slices dating to the 1960-1970s in most lakes except those in the high Arctic, where maxima were generally in surface slices. The onset of elevated ΣPCB deposition was delayed in the high Arctic (1950-1960s) relative to the midlatitude and sub-Arctic lakes (1930-1940s). The high proportions of lower chlorinated congeners and the delayed appearance of PCBs are consistent with predictions of the global fractionation model.
机译：进行了对湖泊沉积物中PCB浓度和通量的研究，以检验“整体分馏”假说，即半挥发性有机物的沉积将下降，而更具挥发性的同类物将在极地富集。沉积岩心是从加拿大11个偏远湖泊中收集的，范围从49°N到82°N，并且使用过量的〜（210）Pb和〜（137）Cs进行了年代测定。通过毛细管GC-ECD分析沉积物提取物中的多达90种PCB同类物，并通过GC /高分辨率MS进行确认。表面切片中的总PCB（ΣPCB）浓度范围为2.4至39 ng g〜（-1）（干重），并且没有纬度趋势。随着北纬度的增加，ΣPCB的通量（ng m〜（-2）yr〜（-1））和库存总量以及四-八氯联苯的总含量下降，而二/三氯联苯的通量（-m _（-2）yr〜（-1））则没有纬度趋势。随着纬度的增加，ΣPCB的二/三氯同类物的比例也显着增加，而八氯联苯的总量却下降了。除北极高海拔地区的最高湖泊外，大多数湖泊中直到1960年至1970年代的地下切片中都观察到最大ΣPCB浓度。相对于中纬度和亚北极湖（1930-1940s），高海拔北极地区（1950-1960年代）ΣPCB沉积的开始被延迟了。低比例氯化物同源物的比例很高以及多氯联苯的出现延迟与全球分馏模型的预测一致。

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