Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
Ontario Ministry of Environment and Climate Change, 40 St. Clair Avenue West, Toronto, Ontario M4V 1M2, Canada.
Environ Sci Technol. 2017 Feb 7;51(3):1811-1819. doi: 10.1021/acs.est.6b05370. Epub 2017 Jan 12.
Intersex in fish downstream of municipal wastewater treatment plants (MWWTPs) is a global concern. Consistent high rates of intersex in male rainbow darter (Etheostoma caeruleum) have been reported for several years in the Grand River, in southern Ontario, Canada, in close proximity to two MWWTPs. The larger MWWTP (Kitchener) recently underwent upgrades that included the conversion from a carbonaceous activated sludge to nitrifying activated sludge treatment process. This created a unique opportunity to assess whether upgrades designed to improve effluent quality could also remediate the intersex previously observed in wild fish. Multiple years (2007-2012) of intersex data on male rainbow darter collected before the upgrades at sites associated with the MWWTP outfall were compared with intersex data collected in postupgrade years (2013-2015). These upgrades resulted in a reduction from 70 to 100% intersex incidence (preupgrade) to <10% in postupgrade years. Although the cause of intersex remains unknown, indicators of effluent quality including nutrients, pharmaceuticals, and estrogenicity improved in the effluent after the upgrades. This study demonstrated that investment in MWWTP upgrades improved effluent quality and was associated with an immediate change in biological responses in the receiving environment. This is an important finding considering the tremendous cost of wastewater infrastructure.
污水处理厂（MWWTP）下游鱼类的雌雄间性是一个全球性的问题。在加拿大安大略省南部的格兰德河，靠近两个 MWWTP 的地方，多年来一直报道虹彩镖鲈（Etheostoma caeruleum）雄性个体中持续存在高比例的雌雄间性。较大的 MWWTP（基奇纳）最近进行了升级改造，包括将碳源活性污泥转化为硝化活性污泥处理工艺。这为评估旨在改善出水水质的升级改造是否也能修复先前在野生鱼类中观察到的雌雄间性提供了独特的机会。在与 MWWTP 出水口相关的地点，对升级前的雄性虹彩镖鲈进行了多年（2007-2012 年）的雌雄间性数据收集，然后与升级后的年份（2013-2015 年）进行了比较。这些升级改造使雌雄间性的发生率从 70%到 100%（升级前）降低到升级后的 <10%。尽管雌雄间性的原因仍不清楚，但在升级后，出水质量的指示物，包括营养物、药物和雌激素，得到了改善。这项研究表明，对 MWWTP 升级改造的投资改善了出水质量，并与受纳环境中生物反应的即时变化相关。考虑到废水基础设施的巨大成本，这是一个重要的发现。
