AUTHORS: Erin L. Pulster, Rebecca Dorman, Jason Magnuson, Brittany Perrotta, Heather Walsh, Cheyenne R. Smith, Vicki Blazer, David Soucek, and Jeffery Steevens
ABSTRACT: Smallmouth Bass (SMB, Micropterus dolomieu) are economically important, freshwater game fish found throughout North America. This species is a focus of research due to recent disease and mortality events observed in some areas of the northeastern United States. PFOS levels measured in the plasma of Smallmouth Bass collected in the Chesapeake Bay Watershed ranged from 20-574 ng/mL. In comparison, PFOS levels measured in muscle tissues from Smallmouth Bass collected nationwide ranged from 0.35 – 110 ng/g. Studies conducted for more than a decade have documented episodic mortality events, high prevalence of skin lesions, endocrine and reproductive disruption in populations of Smallmouth Bass collected in various watersheds. Many of these studies indicated this species is likely subjected to multiple stressors and environmental contaminant exposures, yet no single chemical has been clearly associated with observed impacts. The objectives of this study were to conduct sublethal health assessments in early life stage SMB following exposures to environmentally relevant concentrations of PFOS. Smallmouth Bass embryos (24-hpf) were collected from existing brood stock and cultures at the Columbia Environmental Research Center. Exposures (control, low, high treatments) were conducted for a minimum duration of 30-dph in large flow through water systems with pulsed intermittent diluters. The selection of PFOS concentrations is based on surface water concentrations from recent national surveys and highly impacted sites where SMB are found. In this study, the low exposure concentration is the 95th percentile of PFOS concentrations (24 ng/L) reported in nationwide surface water. The high exposure concentration (96 ng/L) represents PFOS concentrations found in surface water from Ashumet Pond, a highly PFAS-impacted site located in Massachusetts. Traditional toxicology and omics-based endpoints (survival, growth, transcriptomics, microbiome, gene transcript abundance, histopathological changes, behavioral assays) were used to unravel the subtle impacts of chronic PFOS exposures in early life stage Smallmouth Bass.
