Brown bullhead at the St. Lawrence River (Cornwall) Area of Concern: health and endocrine status in the context of tissue concentrations of PCBs and mercury.

The St. Lawrence River, at Cornwall Ontario, has accumulated sediment contaminants, mainly mercury (Hg) and polychlorinated biphenyls (PCBs), from industrial point sources over many years. Although those sources are past, the river at Cornwall remains an Area of Concern (AOC). Because of remediation and other changes in the AOC, improved knowledge of contaminants in wild-fish and their putative links to health effects could help decision makers to better assess the AOC's state. Thus, we compared tissue concentrations of Hg, PCBs, morphometric measures of health, and biomarkers of exposure, metabolic-, and reproductive health in native brown bullhead (Ameiurus nebulosus) from the AOC to those of upstream reference fish. Linear discriminant analysis separated the adult fish of both sexes among upstream and downstream sites without misclassification. Burdens of total-Hg (all sites) and PCB toxic equivalents (downstream sites) exceeded the guidance for the protection of wildlife consumers. There were subtle effects of site on physiological variables, particularly in female fish. Total-Hg in tissue correlated negatively to plasma testosterone and 17ß-estradiol in female fish at Cornwall: moreover, concentrations of both hormones were lower within the AOC compared to reference site fish. A similar effect on vitellogenin, which was uncorrelated to E2/T at the downstream sites, indicated the potential for reproductive effects. Downstream fish also had altered thyroidal status (T3, TSH, and ratio of thyroid epithelial cell area to colloid area). Despite spatial and temporal variability of the endocrine-related responses, these subtle effects on fish health within the AOC warrant further study.

Reduced anxiety is associated with the accumulation of six serotonin reuptake inhibitors in wastewater treatment effluent exposed goldfish Carassius auratus.

Pharmaceuticals and personal care products (PPCPs) have been found in wastewater treatment plant (WWTP) effluents and their recipient watersheds. To assess the potential of WWTP effluents to alter fish behaviour, we caged male goldfish (Carassius auratus) for 21-days at three sites along a contamination gradient downstream from a WWTP which discharges into Cootes Paradise Marsh, on the western tip of Lake Ontario. We also included a fourth caging site as an external reference site within Lake Ontario at the Jordan Harbour Conservation Area. We then measured concentrations of PPCPs and monoamine neurotransmitters in caged goldfish plasma, and conducted behavioural assays measuring activity, startle response, and feeding. We detected fifteen different PPCPs in goldfish plasma including six serotonin reuptake inhibitors (amitriptyline, citalopram, fluoxetine/norfluoxetine, sertraline, venlafaxine, and diphenhydramine). Plasma concentrations of serotonin were significantly greater in plasma of fish caged closer to the WWTP effluent outfall site. The fish caged near and downstream of the WWTP effluent were bolder, more exploratory, and more active overall than fish caged at the reference site. Taken together, our results suggest that fish downstream of WWTPs are accumulating PPCPs at levels sufficient to alter neurotransmitter concentrations and to also impair ecologically-relevant behaviours.

Altered expression of metabolites and proteins in wild and caged fish exposed to wastewater effluents in situ.

Population growth has led to increased global discharges of wastewater. Contaminants that are not fully removed during wastewater treatment, such as pharmaceuticals and personal care products (PPCPs), may negatively affect aquatic ecosystems. PPCPs can bioaccumulate causing adverse health effects and behavioural changes in exposed fish. To assess the impact of PPCPs on wild fish, and to assess whether caged fish could be used as a surrogate for resident wild fish in future monitoring, we caged goldfish in a marsh affected by discharges of wastewater effluents (Cootes Paradise, Lake Ontario, Canada). We collected plasma from resident wild goldfish, and from goldfish that we caged in the marsh for three weeks. We analyzed the plasma proteome and metabolome of both wild and caged fish. We also compared proteomic and metabolic responses in caged and wild fish from the marsh to fish caged at a reference site (Jordan Harbour Conservation Area). We identified significant changes in expression of over 250 molecules that were related to liver necrosis, accumulation and synthesis of lipids, synthesis of cyclic AMP, and the quantity of intracellular calcium in fish from the wastewater affected marsh. Our results suggest that PPCPs could be affecting the health of wild fish populations.

Wild fish from the Bay of Quinte Area of Concern contain elevated tissue concentrations of PCBs and exhibit evidence of endocrine-related health effects.

The Bay of Quinte (BOQ) is an Area of Concern listed under the Great Lakes Water Quality Agreement. The presence of dioxins and dioxin-like PCBs in fish in the BOQ AOC has led to restrictions on fish consumption by humans, which is a beneficial use impairment. Adult yellow perch (Perca flavescens) and brown bullhead (Ameiurus nebulosus) were sampled from Trenton, Belleville, and Deseronto (reference site) in the BOQ. A suite of hormone assays and various measures of exposure and/or sublethal health effects were used to assess the health status of fish of both species and sex. Condition factor, hepatosomatic index, ethoxyresorufin-O-deethylase activity, circulating steroid and thyroid hormones, thyroid activation, oocyte size distribution, spermatogenic cell stages, and plasma vitellogenin were among the endpoints that were significantly (p < 0.05) affected by location. Many of those effects corresponded with significantly (p < 0.05) greater tissue concentrations of polychlorinated biphenyls (PCBs) at Belleville and Trenton. Hepatic extracts from brown bullhead sampled from Trenton had significantly (p < 0.05) greater binding activity to the androgen receptor and sex steroid binding protein. Taken together, these data and preliminary data from a concomitant study suggest that PCBs are likely being hydroxylated in vivo, resulting in enhanced bioactivity at endocrine receptors and measurable health responses. The present study supports the growing body of evidence that PCBs and their metabolites can affect fish thyroid and steroid hormone systems.