title: Reduction of Intersex in a Wild Fish Population in Response to Major Municipal Wastewater Treatment Plant Upgrades.
abstract: 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.
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Keegan A
authors.identifier: 0000-0003-2878-5981
authors.initials: KA
authors.lastname: Hicks
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Meghan L M
authors.initials: ML
authors.lastname: Fuzzen
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Emily K
authors.initials: EK
authors.lastname: McCann
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Maricor J
authors.initials: MJ
authors.lastname: Arlos
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Bragg
authors.affiliation: Ontario Ministry of Environment and Climate Change, 40 St. Clair Avenue West, Toronto, Ontario M4V 1M2, Canada.
authors.forename: Sonya
authors.initials: S
authors.lastname: Kleywegt
authors.affiliation: Aquatic Contaminant Research Division, Water Science and Technology Branch, Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, Ontario L7S 1A1, Canada.
authors.forename: Gerald R
authors.initials: GR
authors.lastname: Tetreault
authors.affiliation: Aquatic Contaminant Research Division, Water Science and Technology Branch, Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, Ontario L7S 1A1, Canada.
authors.forename: Mark E
authors.initials: ME
authors.lastname: McMaster
authors.affiliation: Department of Biology, University of Waterloo , 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Servos
mesh_terms: D000818:Animals; D012734:Disorders of Sex Development / Q000139:chemically induced*; D005393:Fish Diseases / Q000139:chemically induced*; D008297:Male; D010471:Perches; D045483:Rivers; D062065:Wastewater
chemical_list: D062065:Wastewater