Increased Susceptibility of Juvenile Chinook Salmon to Vibriosis after Exposure to Chlorinated and Aromatic Compounds Found in Contaminated Urban Estuaries

Abstract

Saltwater-adapted juvenile chinook salmon Oncorhynchus tshawytscha exposed to aromatic and chlorinated compounds, representative of contaminants found in urban estuaries in Puget Sound, have a higher susceptibility to vibriosis than do fish exposed only to the solvent vehicle. Susceptibility to vibriosis was assessed by examining the percent cumulative mortality of the salmon after exposure to the bacterial pathogen Vibrio anguillarum. The aromatic and chlorinated compounds examined consisted of a sediment extract from the Hylebos Waterway that was enriched in butadienelike compounds (chlorinated-enriched Hylebos Waterway sediment extract [CHWSE]), a model mixture of polycyclic aromatic hydrocarbons (PAHs), a polychlorinated biphenyl mixture (Aroclor 1254), hexachlorobutadiene (HCBD), and 7,12-dimethylbenz[a]anthracene (DMBA). Two trials were conducted. In trial l, the percent cumulative mortality of juvenile chinook salmon exposed to V. anguillarum after receiving either CHWSE, HCBD, or the model mixture of PAHs ranged from 28% to 31% compared with the 16% observed in the acetone: emulphor control group at 7 d post-bacterial challenge. In trial 2, the net cumulative mortality of juvenile chinook salmon exposed to V. anguillarum after receiving either DMBA or Aroclor 1254 ranged from 46% to 49% compared with the 25% observed in the acetone:emulphor control group at 9 d postchallenge. The differences in mortality between groups of fish in the treated and control groups in both trials were significant at P Յ 0.05. These findings suggest that a higher predisposition to infection and subsequent disease can occur in salmon exposed to chemical contaminants found in urban estuaries of Puget Sound, Washington.

Contaminant exposure in outmigrant juvenile salmon from Pacific Northwest estuaries of the United States

“…In addition, when held in tanks with flow-through seawater for a period of several months, juvenile salmon from the Duwamish Estuary exhibited reduced growth and reduced disease resistance when compared to salmon from either the Green River Hatchery (the primary source of salmon for the Duwamish Estuary) or to salmon from the nonurban Nisqually system (Arkoosh et al, 1998;Casillas et al, 1995). Similar effects were observed for juvenile salmon from the Hylebos Waterway (Arkoosh et al, 2001;Casillas et al, 1998). Chemical contaminant exposure in the estuary appeared to place additional stresses on juvenile chinook salmon that could affect their long-term health and survival as they enter the marine environment.…”

“…Indeed, adverse health effects have been observed in juvenile salmon from the Duwamish Estuary, which is contaminated with PAHs and PCBs. Fish from this area showed immunosuppression, reduced disease resistance and decreased growth rates (Arkoosh et al, 1991(Arkoosh et al, , 1994(Arkoosh et al, , 1998(Arkoosh et al, , 2001Varanasi et al, 1993;Casillas et al, 1995Casillas et al, , 1998, as well as biochemical alterations such as DNA damage (i.e., PAH-DNA adducts in liver) and induction of cytochrome P4501A (CYP1A), an enzyme that metabolizes selected contaminants including PAHs, dioxins and furans, and dioxin-like PCB congeners McCain et al, 1990;Varanasi et al, 1993;Collier et al, 1998;Stehr et al, 2000). These biochemical alterations are not necessarily indicative of adverse health effects in themselves, but are associated with disease conditions including reproductive and developmental abnormalities and liver disease (Williams et al, 1998;Whyte et al, 2000;Myers et al, 2003).…”

Tissue-Specific Metabolism of Benzo[a]pyrene in Rainbow Trout (Oncorhynchus mykiss): A Comparison between the Liver and Immune Organs

“…In fact, a wide variety of chemicals has been reported to compromise the immune functions of fish and to modulate their susceptibility to infectious pathogens (Rice, 2001;Carlson and Zelikoff, 2008;Segner et al, 2013). One class of chemicals that has been repeatedly shown to affect the immune functions of fish are polycyclic aromatic hydrocarbons (PAHs) (Arkoosh et al, 2001;Carlson et al, 2002;Hutchinson et al, 2003;Carlson et al, 2004b;Reynaud et al, 2004;Kennedy and Farrell, 2008;Danion et al, 2011).…”

Sources, Fate and Effects of Contaminant Emissions in Urban Areas

“…One disturbance can reduce the resilience of organisms to subsequent stresses, e.g. increased susceptibility of fish to infectious disease following exposure to contaminants from stormwater discharges (Arkoosh et al, 2001). This section discusses some of the numerous examples of environmental degradation resulting from widespread urban chemical release to soil, surface water, sediments, groundwater and air.…”