Category: Fish/Shellfish Research
Published: June 2016
Publication number: FPT 20-10
Author(s): Sandra M. O’Neill, José M. Guzmán, Penny Swanson, J. Adam Luckenbach, Denis da Silva, Gina M. Ylitalo, Irvin R. Schultz, Lyndal L. Johnson, Edward S. Hayman, Jennifer Lanksbury, Laurie Niewolny, and James E. West
This project provided a Sound-wide assessment of the presence and biological impact of selected Contaminants of Emerging Concern (CECs) in English sole (Parophrys vetulus), a long standing, key indicator species for toxics monitoring in Puget Sound. This project leveraged field and laboratory assets from an ongoing, long-term toxics monitoring program (Puget Sound Ecosystem Monitoring Program) with regional laboratories developing cutting-edge ecotoxicology techniques (NOAA’s Northwest Fisheries Science Center and Battelle’s Pacific Northwest National Laboratory) to (a) develop analytical methods for, and provide a current evaluation of the extent and magnitude of CEC contamination in English sole and (b) develop cost-effective bioeffects endpoints for these CECs.
Two major classes of CECs were evaluated, estrogenic chemicals (ECs), including three natural estrogens (17β-estradiol, estrone, and estriol), one synthetic estrogen (17α ethynyl estradiol), and three nonsteroidal xenoestrogenic compounds (bisphenol A, nonylphenol and octylphenol); and three selective serotonin reuptake inhibitors (SSRIs; fluoxetine, sertraline and citalopram) that may amplify the effects of ECs. The EC bioeffect endpoint was a method for measuring vitellogenin (VTG) induction, a widely accepted biological indicator of EC exposure.
The project successfully achieved its goals of developing new tools for exposure metrics for ECs in fish bile, a bioeffects metric for exposure to ECs, and measuring SSRIs in English sole. These tools may be applied in upcoming 2017 English sole surveys, and will be further refined as we incorporate them into WDFW/PSEMP’s biennial English sole contaminant survey. We also combined these new methods with existing methods on English sole tissue samples collected in 2011 and 2013 to identify:
- continued altered reproductive timing in female fish from Seattle Waterfront in Elliott Bay, likely from exposure to ECs,
- relatively high concentrations of ECs in sole from highly-developed urbanized habitats, especially Seattle Waterfront and Sinclair Inlet,
- widespread VTG induction in male sole, with highest values primarily observed in highly developed urbanized habitats, especially Tacoma Waterway and Seattle Waterfront,
- little or no recent exposure of English sole to SSRIs, likely because sole did not occur near enough to, or forage long enough near, putative SSRI sources (such as wastewater treatment plants).
Although ECs appeared concentrated in highly developed areas and we observed the greatest EC effects in urban areas, the correlation between EC exposure-and-effects was less clear on an individual fish basis. The reasons for this could be:
- a mismatch in timing of our sampling between exposure and effects,
- differences in kinetics and metabolism of various ECs and VTG mRNA synthesis
- insufficient sample sizes to achieve enough power to detect relationships, if they existed, because of the highly variable EC and VTG values measured in individual fish within a station, and
- the presence of androgenic or anti-estrogenic chemicals that may mask or alter the effects of ECs.
These results highlight the need for continued work to refine these tools for monitoring indicator species such as English sole. Although effects from exposure to ECs seemed clear in some cases, high variability in response metrics precluded unambiguous conclusions in some cases. Power analysis of existing samples will help to define the sample sizes needed to identify spatial and temporal differences for upcoming monitoring efforts. Evaluation of multiple metrics (histological examination of gonads, hepatic VTG induction, and measurement of biliary ECs) is still appropriate and necessary to understand and track the health effects of these chemicals. Controlled dosing studies in the lab may help to elucidate health effects thresholds, which are needed to evaluate the measurements made in wild English sole, and to elucidate the level of normal VTG mRNA synthesis in natural, unexposed male English sole, if one exists. Finally, continued evaluation of additional exposure and health metrics, including assessment of VTG proteins in plasma, is warranted as they become available, and more cost effective.
Establishing VTG induction as a monitoring tool for English sole fills a recognized, important gap in the Puget Sound Partnership’s Toxics in Fish Vital Sign. Combining results from this project with existing PSEMP efforts to monitor a wide range of other contaminants will provide a balanced approach for prioritizing contaminant-related recovery efforts in Puget Sound.