PARENT SESSION

PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday

(PM234) P450 levels of Stellars eiders and Harlequin ducks from the Aleutian Islands and Alaska Peninsula.

Arrieta, D¹, Miles, A², Flint, P³, Trust, K⁴, Hollmen, T⁵, Tsao, D², Seger, C², Sheetenhelm, E², Wilson, B¹, ¹ Department of Animal Science and Environmental Toxicology, Davis, CA, USA² USGS WERC, Davis Field Station, Davis, CA³ USGS Alaska Science Center, Anchorage, AK, USA⁴ USFWS Anchorage Regional Office, Anchorage, AK, USA⁵ Alaska Sealife Center, Seward, AK, USA

ABSTRACT- Decline in Stellars eiders (STEI - Polysticta stellar in North America has resulted in listing of these Alaskan breeding populations under the Endangered Species Act. Persistence of environmental contaminants, such as polycyclic aromatic hydrocarbons, is suspected of contributing to their decline. In 2002 and 2003, 73 STEI and 83 Harlequin ducks (HADU - Histrionicus histrionicus ) were captured to determine exposure to petroleum-based hydrocarbons or other organic contaminants associated with industrial activities, e.g., ports, seafood processors, and military installations at Dutch Harbor (Unalaska Island) and Sand Point (Popov Island). Surgical biopsies of liver were obtained in the field and the birds released after recovery. Samples were flash frozen and sent for analyses. Cytochrome P-450 was measured with a micro method for 7- ethoxyresorufin-O-deethylase activity (EROD) on samples as little as 4 mg wet weight. Livers collected from Mallard duck (Anas platyrhynchos) and White leghorn chicken (Gallus gallus) embryos injected with 2 mg/egg of -napthoflavone (BNF), a known P-450 inducer, were assayed 24 hours later as positive controls. EROD activity was 25-fold higher with BNF compared to controls. Field studies showed STEI EROD activity ranged from 9 pmol/min/mg protein (Captains Bay, Dutch Harbor) to 53.6 pmol/min/mg protein (Sand Point). HADU EROD activity ranged from 46.1 pmol/min/mg protein (Captains Bay) to 280 pmol/min/mg protein (Sand Point). EROD activities were within the range previously reported for other seabirds. STEI birds were less induced than HADU birds, suggesting they exhibited either higher sensitivity or lower exposures. A dose/response study showed there was a maximal 4-fold induction in P450 of captured STEI with 20 mg/kg BNF. These data suggest a possible correlation between P450 levels of the ducks and exposure to pollutants that will be tested by the chemical analyses underway. Supported by USFWS (701810M094), USGS (9370A2GIA), and EPA-PEEIR (R-82867601).

Key words: Alaskan Islands, seabirds, organic contaminants, EROD