Municipal and industrial wastewater effluent is an important source of water for lotic systems, especially during periods of low flow. The accumulated wastewater effluent flows—expressed as a percentage of total streamflow (ACCWW%)—contain chemical mixtures that pose a risk to aquatic life; fish may be particularly vulnerable when chronically exposed. Although there has been considerable focus on individual‐level effects of exposure to chemical mixtures found in wastewater effluent, scaling up to population‐level effects remains a challenging component needed to better understand the potential consequences of exposure in wild populations. This may be particularly important under a changing climate in which wastewater reuse could be essential to maintain river flows. We evaluated the effects of chronic exposure to wastewater effluent, as measured by ACCWW%, on the relative abundance of young‐of‐year (YOY), juvenile, and adult smallmouth bass (Micropterus dolomieu) populations in the Shenandoah River Watershed (USA). We found that increases in ACCWW% in the previous year and during the prespawn period were negatively correlated with the relative abundance of YOY, resulting in an average 41% predicted decrease in abundance (range = 0.5%–94% predicted decrease in abundance). This lagged effect suggests that adult fish reproductive performance may be compromised by chemical exposure during periods of high ACCWW%. No relationships between ACCWW% and juvenile or adult relative abundance were found, suggesting that negative effects of ACCWW% on YOY abundance may be offset due to compensatory mechanisms following higher ACCWW% exposure. Understanding the effects of wastewater effluent exposure at multiple levels of biological organization will help in the development of management strategies aimed at protecting aquatic life. Environ Toxicol Chem 2024;00:1–11. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

中文翻译：

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废水回用对美国谢南多厄河流域小口黑鲈 (Micropterus dolomieu) 相对丰度的影响

市政和工业废水是污水系统的重要水源，特别是在低流量时期。累积的废水流量（以占总流量的百分比 (ACCWW%) 表示）含有对水生生物构成风险的化学混合物；长期接触鱼类可能特别容易受到伤害。尽管人们非常关注暴露于废水中发现的化学混合物对个体水平的影响，但扩大到群体水平的影响仍然是一个具有挑战性的部分，需要更好地了解暴露在野生种群中的潜在后果。在气候变化的情况下，废水再利用对于维持河流流量至关重要，这一点可能尤其重要。我们评估了长期暴露于废水排放物（以 ACCWW% 为衡量标准）对幼鱼（YOY）、幼鱼和成年小口黑鲈相对丰度的影响（多罗密口鲈）谢南多厄河流域（美国）的人口。我们发现，前一年和产卵前时期 ACCWW% 的增加与同比相对丰度呈负相关，导致预测丰度平均下降 41%（范围 = 0.5%–94% 预测丰度下降）。这种滞后效应表明，在高 ACCWW% 期间，成鱼的繁殖性能可能会因化学暴露而受到损害。没有发现 ACCWW% 与幼年或成虫相对丰度之间的关系，这表明 ACCWW% 对 YOY 丰度的负面影响可能会由于较高 ACCWW% 暴露后的补偿机制而被抵消。了解废水排放物暴露对生物组织多个层面的影响将有助于制定旨在保护水生生物的管理策略。环境毒理化学2024；00：1–11。 © 2024 作者。环境毒理学和化学由 Wiley periodicals LLC 代表 SETAC 出版。本文由美国政府雇员撰写，他们的作品在美国属于公共领域。