Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, Ontario, Canada L7R 4A6.
Environ Sci Technol. 2012 Jun 5;46(11):5842-50. doi: 10.1021/es3006095. Epub 2012 May 17.
Perfluoroalkyl contaminants (PFCs) were determined in Lake Ontario Lake Trout sampled annually between 1997 and 2008 in order to assess how current trends are responding to recent regulatory bans and voluntary phase-outs. We also combined our measurements with those of a previous study to provide an updated assessment of long-term trends. Concentrations of PFCs generally increased from the late 1970s until the mid-1980s to mid-1990s, after which concentrations either remained unchanged (perfluorooctane sulfonate (PFOS) and perfluorocarboxylates) or declined (perfluorodecanesulfonate (PFDS)). The temporal trends were assessed using three models, quadratic, exponential rise to maximum, and two-segment linear piecewise function, and then evaluated for best fit using Akaike Information Criteria. For PFOS and perfluorocarboxylates, the exponential rise to maximum function had the best fit. This is particularly interesting for PFOS as it suggests that although concentrations in Lake Ontario Lake Trout may have stopped increasing in response to voluntary phase-outs in 2000-2002, declines have yet to be observed. This may be due to continuing input of PFOS from products still in use and/or slow degradation of larger precursor molecules. A power analysis of PFOS suggested that 15 years of data with a within-year sample size of 10 is required to obtain sufficient power (80%) to detect a 5% decreasing trend. However, the length of the monitoring program had a greater influence on the ability to detect a trend compared to within-year sample size. This provides evidence that additional sampling years are required to detect a response to bans and phase-outs, given the variability in the fish data. The lack of observed declines of perfluorocarboxylate residues in fish may be expected as regulations for these compounds were only recently enacted. In contrast to the other compounds, the quadratic model had the best fit for PFDS. The results of this study emphasize the importance of long-term monitoring for assessing the effectiveness of bans and phase-outs on PFCs in the environment.
为了评估当前趋势对最近的法规禁令和自愿淘汰的反应，我们在 1997 年至 2008 年期间每年对安大略湖湖鳟鱼进行采样，以测定全氟烷基污染物（PFCs）的含量。我们还将我们的测量结果与之前的一项研究相结合，提供了对长期趋势的最新评估。PFCs 的浓度通常从 20 世纪 70 年代末到 80 年代中期到 90 年代中期增加，此后浓度要么保持不变（全氟辛烷磺酸（PFOS）和全氟羧酸），要么下降（全氟癸烷磺酸（PFDS））。使用三种模型（二次、指数上升到最大值和两段线性分段函数）评估时间趋势，然后使用赤池信息量准则评估最佳拟合。对于 PFOS 和全氟羧酸，指数上升到最大值函数具有最佳拟合。这对于 PFOS 来说特别有趣，因为这表明尽管安大略湖湖鳟鱼中的浓度可能已经停止增加，以应对 2000-2002 年的自愿淘汰，但尚未观察到下降。这可能是由于仍在使用的产品继续输入 PFOS 和/或较大前体分子的缓慢降解。PFOS 的幂分析表明，需要 15 年的数据和每年 10 个样本的样本量，才能获得足够的（80%）检测 5%下降趋势的能力。然而，与每年的样本量相比，监测计划的长度对检测趋势的能力有更大的影响。鉴于鱼类数据的可变性，这表明需要更多的采样年份来检测对禁令和淘汰的反应。相比之下，对于其他化合物，二次模型对 PFDS 具有最佳拟合。本研究的结果强调了长期监测对于评估环境中 PFCs 的禁令和淘汰效果的重要性。
