Exposure of Pacific Herring (Clupea pallasi) to Persistent Organic Pollutants in Puget Sound and the Georgia Basin

The Puget Sound Ambient Monitoring Program has monitored spatial and temporal trends of toxic contaminants in Puget Sound fishes from 1989 to the present. A pilot study on the feasibility of adopting Pacific herring (Clupea harengus) as an additional indicator species was conducted in 1995, and regular monitoring of herring begun in 1999. Pilot sampling of toxic contaminants in herring eggs was also begun. We have focused on two classes of toxic contaminants that accumulate in fish tissues, (polychlorinated biphenyls (PCBs), and pesticides (DDT, its metabolites, and hexachlorobenzene (HCB)), and one class that does not accumulate in fish tissues (polycyclic aromatic hydrocarbons (PAHs)). PCBs and pesticides were measured as concentrations from composites of whole fish. Recent exposure to PAHs was estimated from composites of fish bile, by measuring concentration of PAH-metabolites known as Fluorescing Aromatic Compounds (FACs). We also measured PAH concentrations in eggs-recently- laid by two distinct spawning stocks in Puget Sound, one near an oil refinery and one away from suspected oil sources. Total PCBs in whole herring bodies in two Central/South Puget Sound locations ranged from 125 to 350 µg/kg, and were significantly greater than three northern locations (all less than 125 µg/kg). ppDDE comprised the bulk of the body burden of DDT and DDT-metabolite compounds in herring, with the greatest concentrations observed from the central Sound station (40 to 175 µg/kg. Herring from all other locations had concentrations less than 40 µg/kg. HCB was detected often, but in low concentrations (<1.8 µg/kg).

Biliary FACs (metabolites of benzo-a-pyrene, naphthalene, and phenanthrene) were significantly greater in herring from a central Sound location than northern and a southern Sound locations. We observed no correlation between FAC concentration and biliary protein.

PAH and PAH-homologue compounds were not detected from herring eggs laid by the Port Gamble spawning stock at two locations (away from an oil refinery), however those eggs were only one-day-old. Eggs laid by the Cherry Point spawning stock at the three sites (near an oil refinery) were 7 to 8 days old, which confounded valid comparison with the Port Gamble egg samples. Eggs from two of the three Cherry Point sites had detected PAHs (dibenzothiophene, acenaphthene, naphthalene, 2-methylnaphthalene, and C- 1 naphthalenes) ranging in concentration from 1.0 to 3.5 µg/kg (wet wt.) Presence of some of these compounds is consistent with exposure to Alaska north slope crude oil, (which is refined nearby) however, concentrations were below a published lowest observable effects concentration (LOEC).