posted on 2023-12-28, 20:09authored byJessica I. Lundin, Paul M. Chittaro, Irvin R. Schultz, Mary R. Arkoosh, Mary C. Baker, David H. Baldwin, Tracy K. Collier, Barbara L. French, John W. Kern, Jana S. Labenia, Tiffany L. Linbo, Amy A. Merten, Cameron M. Schuster, Karl B. Veggerby, Gina M. Ylitalo, Nathaniel L. Scholz, Joseph P. Dietrich
Chemical pollution
can degrade aquatic ecosystems. Chinook
salmon
in contaminated habitats are vulnerable to health impacts from toxic
exposures. Few studies have been conducted on adverse health outcomes
associated with current levels and mixtures of contaminants. Fewer
still address effects specific to the juvenile life-stage of salmonids.
The present study evaluated contaminant-related effects from dietary
exposure to environmentally relevant concentrations and mixture profiles
in juvenile Chinook salmon from industrialized waterways in the U.S.
Pacific Northwest using two end points: growth assessment and disease
susceptibility. The dose and chemical proportions were reconstituted
based on environmental sampling and analysis using the stomach contents
of juvenile Chinook salmon recently collected from contaminated, industrialized
waterways. Groups of fish were fed a mixture with fixed proportions
of 10 polychlorinated biphenyls (PCBs), 3 dichlorodiphenyltrichloroethanes
(DDTs), and 13 polycyclic aromatic hydrocarbons (PAHs) at five concentrations
for 35 days. These contaminant compounds were selected because of
elevated concentrations and the widespread presence in sediments throughout
industrialized waterways. Fork length and otolith microstructural
growth indicators were significantly reduced in fish fed environmentally
relevant concentrations of these contaminants. In addition, contaminant-exposed
Chinook salmon were more susceptible to disease during controlled
challenges with the pathogen Aeromonas salmonicida. Our results indicate that dietary exposure to contaminants impairs
growth and immune function in juvenile Chinook salmon, thereby highlighting
that current environmental exposure to chemicals of potential management
concern threatens the viability of exposed salmon.