Reproductive health of bass in the Potomac, USA, 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.

Reproductive health indicators of fishes from Pennsylvania watersheds: association with chemicals of emerging concern

“…Species included SMB, a member of the Centrarchidae family, representing carnivorous, pelagic species. SMB have been shown to be a sensitive indicator species for EDC studies, expressing signs of estrogenic exposure such as TO and plasma vitellogenin (Vtg) in males (Baldigo et al 2006; Blazer et al 2007, 2012; Hinck et al 2009; Iwanowicz et al 2009). Suckers are benthic feeding, bottom-dwelling species in the Catostomidae family.…”

“…Since then, mortalities have also occurred in the Shenandoah and the Monocacy Rivers, both tributaries of the Potomac River, and moderate to high prevalence of TO has been documented at these sites as well (Blazer et al 2007; Iwanowicz et al 2009; Blazer et al 2010). Mortalities in the Potomac drainage have involved mature adult fishes and occurred in the spring.…”

Kemp's Ridley Sea Turtle Saga and Setback: Novel Analyses of Cumulative Hatchlings Released and Time-Lagged Annual Nests in Tamaulipas, Mexico

“…These compounds enter the aquatic environment via wastewater treatment plants, agricultural facilities, and farm runoff (Culp et al 2000;Folmar et al 1996;Wallin et al 2002;Wildhaber et al 2000). These products are the source of both natural and synthetic substances including, but not limited to, polychlorinated biphenyls, phthalates, pesticides, heavy metals, alkylphenols, polycyclic aromatic hydrocarbons, 17β-estradiol, 17α-ethinylestradiol, and bisphenol A (Aguayo et al 2004;Björkblom et al 2009;Iwanowicz et al 2009;Nakada et al 2004;Pait and Nelson 2002). The impact of these exposures on Gulf sturgeon is unknown, but other species of fish are affected in rivers and streams.…”

Research trends on emerging environment pollutants – a review

“…These results do not change the fact that long-term exposure to even low concentrations of active endocrine compounds may adversely affect human health [41]. Increased presence of the hermaphrodite fish populations in the reservoirs fed with purified water flowing from sewage treatment plants was observed in the US, Asia and Europe [42][43][44]. Still, however, there is a need to prove a direct relation between the presence of estrogens in surface waters, and changes in the sexuality of fish populations found in rivers, lakes and streams.…”