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首页> 外文期刊>Ecological Applications >EVIDENCE THAT PCBS ARE APPROACHING STABLE CONCENTRATIONS IN LAKE MICHIGAN FISHES
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EVIDENCE THAT PCBS ARE APPROACHING STABLE CONCENTRATIONS IN LAKE MICHIGAN FISHES

机译：有证据表明PCBS正在接近密歇根湖鱼类的浓度

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We examined PCB concentration data for seven species of Lake Michigan fishes to determine what trends were apparent approximate to 20 yr after PCB restrictions became effective. Total PCB concentrations in all seven species, lake trout (Salvelinus namaycush), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), alewife (Alosa pseudoharengus), and bloater chub (Coregonus hoyi) declined and appeared to stabilize in the mid-to-late 1980s. Concentrations in two species, chinook and coho salmon, appear to have increased slightly since the late 1980s. All species are currently well below the high PCB levels that existed when PCB use was curtailed in the 1970s. We believe stabilizing concentrations are the result of large pools of PCBs that are being recycled in the environment. Atmospheric and sediment PCB inputs to the lake probably constitute current PCB sources. Increasing concentrations in chinook and coho salmon are likely the result of changing growth dynamics caused by alterations in the mid-trophic levels of the food web. Median stable PCB concentrations estimated in this analysis are below the current FDA action level of 2 mg/kg, but not appreciably below this threshold. Improvements beyond these levels may result if management practices that maximize fish growth rates are implemented. Detection of future improvements in PCB levels may require samples in the range of 1000-2000 fish because of the high variability in PCB concentrations among individuals. [References: 43]
机译：我们检查了密歇根湖鱼类的7种鱼类的PCB浓度数据，以确定在PCB限制生效后大约20年的趋势明显。湖鳟（Salvelinus namaycush），虹鳟（Oncorhynchus mykiss），褐鳟（Salmo trutta），奇努克鲑鱼（Oncorhynchus tshawytscha），银大麻哈鱼（Oncorhynchus kisutch），芦荟（Alosa pseudoharengus）和膨胀（Coregonus hoyi）下降，并在1980年代中后期趋于稳定。自1980年代后期以来，印度努契克（Chookook）和银大麻哈鱼（coho鲑）这两个物种的浓度似乎有所增加。目前，所有物种均远低于1970年代限制使用PCB时存在的高PCB水平。我们认为稳定的浓度是在环境中回收大量PCB的结果。湖泊的大气和沉积物多氯联苯输入可能构成了目前的多氯联苯来源。 chinook和银大麻哈鱼中浓度的增加可能是由于食物网中营养水平的变化引起的生长动态变化而导致的。该分析中估计的稳定PCB浓度中值低于目前的FDA行动水平2 mg / kg，但未明显低于该阈值。如果实施最大限度提高鱼类生长率的管理措施，则可能会导致超出这些水平的改善。由于个体中PCB浓度的高变异性，要检测出PCB含量未来的提高可能需要1000-2000条鱼的样本。 [参考：43]

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