title: Reproductive health of bass in the Potomac, U.S.A., drainage: part 1. Exploring the effects of proximity to wastewater treatment plant discharge.
abstract: Intersex (specifically, testicular oocytes) has been observed in male smallmouth bass (SMB; Micropterus dolomieu) and other centrarchids in the South Branch of the Potomac River, U.S.A., and forks of the Shenandoah River, U.S.A., during the past five years. This condition often is associated with exposure to estrogenic endocrine-disrupting chemicals in some fish species, but such chemicals and their sources have yet to be identified in the Potomac. In an attempt to better understand the plausible causes of this condition, we investigated the reproductive health of bass sampled up- and downstream of wastewater treatment plant (WWTP) effluent point sources on the Potomac River in Maryland, U.S.A. Smallmouth bass were sampled from the Conococheague Creek and the Monocacy River, and largemouth bass (LMB; Micropterus salmoides) were collected near the Blue Plains WWTP on the mainstem of the Potomac River. Chemical analyses of compounds captured in passive samplers at these locations also were conducted. A high prevalence of intersex (82-100%) was identified in male SMB at all sites regardless of collection area. A lower prevalence of intersex (23%) was identified in male LMB collected at the Blue Plains site. When up- and downstream fish were compared, significant differences were noted only in fish from the Conococheague. Differences included condition factor, gonadosomatic index, plasma vitellogenin concentration, and estrogen to testosterone ratio. In general, chemicals associated with wastewater effluent, storm-water runoff, and agriculture were more prevalent at the downstream sampling sites. An exception was atrazine and its associated metabolites, which were present in greater concentrations at the upstream sites. It appears that proximity to effluent from WWTPs may influence the reproductive health of bass in the Potomac watershed, but inputs from other sources likely contribute to the widespread, high incidence of testicular oocytes.
authors.affiliation: National Fish Health Research Laboratory, U.S. Geological Survey, 11649 Leetown Road, Kearneysville, West Virginia 25430, USA. liwanowicz@usgs.gov
authors.forename: Luke R
authors.initials: LR
authors.lastname: Iwanowicz
authors.forename: Vicki S
authors.initials: VS
authors.lastname: Blazer
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Guy
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Pinkney
authors.forename: John E
authors.initials: JE
authors.lastname: Mullican
authors.forename: David A
authors.initials: DA
authors.lastname: Alvarez
mesh_terms: D000818:Animals; D001492:Bass; D012734:Disorders of Sex Development / Q000139:chemically induced / Q000662:veterinary; D052244:Endocrine Disruptors / Q000737:chemistry / Q000633:toxicity*; D004784:Environmental Monitoring; D005260:Female; D005393:Fish Diseases / Q000139:chemically induced; D006066:Gonads / Q000187:drug effects / Q000473:pathology; D008297:Male; D008396:Maryland; D012098:Reproduction / Q000187:drug effects*; D045483:Rivers / Q000737:chemistry*; D014768:Virginia; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014903:West Virginia
chemical_list: D052244:Endocrine Disruptors; D014874:Water Pollutants, Chemical