Biological responses of marine flatfish exposed to municipal wastewater effluent

Abstract

There is increasing concern over the presence of pharmaceutical compounds, personal care products, and other chemicals collectively known as contaminants of emerging concern (CECs) in municipal effluents, yet knowledge of potential environmental impacts related to these compounds is still limited. The present study used laboratory exposures to examine estrogenic, androgenic, and thyroid-related endocrine responses in marine hornyhead turbot (Pleuronichthys verticalis) exposed to CECs from municipal effluents with 2 degrees of treatment. Fish were exposed for 14 d to environmentally realistic concentrations of effluent (0.5%) and to a higher concentration (5%) to investigate dose responses. Plasma concentrations of estradiol (E2), vitellogenin (VTG), 11-keto testosterone, and thyroxine were measured to assess endocrine responses. Contaminants of emerging concern were analyzed to characterize the effluents. Diverse types of effluent CECs were detected. Statistically significant responses were not observed in fish exposed to environmentally realistic concentrations of effluent. Elevated plasma E2 concentrations were observed in males exposed to ammonia concentrations similar to those found in effluents. However, exposure to ammonia did not induce VTG production in male fish. The results of the present study highlight the importance of conducting research with sentinel organisms in laboratory studies to understand the environmental significance of the presence of CECs in aquatic systems.

Organic contaminants of emerging concern in sediments and flatfish collected near outfalls discharging treated wastewater effluent to the Southern California Bight

“…1). The level of wastewater treatment among the POTWs discharging at the outfall locations varies from advanced primary to full secondary 7, 12. Discharge flow capacity for each of these outfalls range between 170 and 350 million gallons per day for a sum total exceeding 1 billion gallons per day.…”

Spatial patterns in markers of contaminant exposure, glucose and glycogen metabolism, and immunological response in juvenile winter flounder (Pseudoplueronectes americanus)

“…Analysis of contaminant levels in sediments at the site of collection and in fish tissues would also provide additional valuable information on exposure, but does not diminish the importance of field data on biological responses, which account for factors affecting bioavailability as well as the possibility of detecting responses from rapidly metabolized compounds such as PAHs, and many estrogenic contaminants such as hormones and hormone mimics. Also, several laboratory studies evaluating exposure to sewage effluents have not shown these biomarkers to link directly to dose (Vidal-Dorsch et al, 2014). Further work will be needed to evaluate what combinations of environment factors (chemical exposure, temperature, hypoxia) may be contributing to the patterns in CYP1A and VTG expression we observed in juvenile flounder.…”

Assessing recovery of in vitro steroid production in male rainbow darter (Etheostoma caeruleum) in response to municipal wastewater treatment plant infrastructure changes

“…All of the exogenous estrogens have the potential to mimic naturally occurring 17β‐estradiol and exert their action in low concentrations, resulting in alterations of absolute and relative concentrations of sex steroids in circulation and in tissues (Hecker et al ). For example, exposure of the marine hornyhead turbot ( Pleuronichthys verticalis ) to estradiol caused significant reduction in 11‐ketotestosterone (Vidal‐Dorsch et al ). Reduction in 11‐ketotestosterone was also observed in a study with male fathead minnow exposed to environmentally relevant concentrations of 17α‐ethinylestradiol for 21 d (Salierno and Kane ).…”