A bleached kraft pulp mill discharging effluent to the Mattagami River in northern Ontario, Canada, closed after almost 90 yr of operation. During its operation, effluent from the mill influenced biota in the downstream areas. To assess shifts in the reliance of biota from mill-derived nutrients, the isotopic composition (δ13 C and δ15 N) of white sucker (Catostomus commersoni) muscle and whole mayflies (Hexagenia sp.) were compared before (1990s) and after the pulp mill's closure (2012-2014). To better understand other potential sources of spatial and temporal change, samples from 3 other tributaries in the basin with dams, ongoing pulp mill operations, sites receiving sewage, and at several reference sites were collected and compared. Irrespective of time period, biota collected at sites downstream of both dams and active pulp mills tended to have elevated δ13 C values, but variable changes in δ15 N (negligible in most cases) when compared with upstream samples. The isotopic composition of mayflies varied at reference sites over time, with decreasing values of δ13 C and δ15 N (mayflies only) with increasing depth, and there was evidence of lower δ13 C in fish after the pulp mill closure. Overall, these results suggest the importance of long-term, regional-scale measurements for documenting the effects of stressors on nutrient use by aquatic species. Environ Toxicol Chem 2020;39:1207-1218. © 2020 SETAC.

中文翻译：

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鱼和无脊椎动物稳定同位素的区域和长期分析表明，制浆厂关闭和其他压力源的影响也很明显。

一台漂白的牛皮纸制浆厂将废水排放到加拿大安大略省北部的Mattagami河，将近运行90年后关闭。在运行过程中，工厂的废水影响了下游地区的生物群。为了评估来自磨坊的养分对生物区系的依赖程度的变化，在浆粕之前（1990年代）和浆粕之后比较了白色吸盘（Catostomus commersoni）肌肉和整个may（Hexagenia sp。）的同位素组成（δ13C和δ15N）。工厂的关闭（2012-2014）。为了更好地了解其他潜在的时空变化来源，收集并比较了流域其他3个支流与大坝，正在进行的制浆厂运行，接收污水的地点以及几个参考地点的样本。不论时间长短 在大坝和活性纸浆厂的下游站点收集的生物群倾向于具有较高的δ13C值，但与上游样本相比，δ15N的变化却是可变的（在大多数情况下可忽略不计）。在参考点，may的同位素组成随时间变化，δ13C和δ15N（仅may）的值随深度增加而降低，并且有迹象表明，制浆厂关闭后鱼中的δ13C较低。总体而言，这些结果表明，长期的区域尺度测量对于记录应激源对水生物种养分利用的影响非常重要。Environ Toxicol Chem 2020； 39：1207-1218。©2020 SETAC。随着深度的增加，δ13C和δ15N（仅可能）值降低，并且有证据表明，制浆厂关闭后鱼中的δ13C较低。总体而言，这些结果表明，长期的区域尺度测量对于记录应激源对水生物种养分利用的影响非常重要。Environ Toxicol Chem 2020； 39：1207-1218。©2020 SETAC。随着深度的增加，δ13C和δ15N（仅可能）值降低，并且有证据表明，制浆厂关闭后鱼中的δ13C较低。总体而言，这些结果表明，长期的区域尺度测量对于记录应激源对水生物种养分利用的影响非常重要。Environ Toxicol Chem 2020； 39：1207-1218。©2020 SETAC。