Jc. Franson et al., BLOOD LEAD CONCENTRATIONS OF SPECTACLED EIDERS NEAR THE KASHUNUK RIVER, YUKON DELTA NATIONAL WILDLIFE REFUGE, ALASKA, Ecotoxicology, 7(3), 1998, pp. 175-181
We collected 342 blood samples from spectacled eiders (Somateria fisch
eri) on their breeding grounds in western Alaska from late May through
to early August 1993-1995. Lead concentrations of greater than or equ
al to 0.50 p.p.m. wet weight were found in the blood of 20% of the adu
lt female eiders, 2% of the adult males and 6% of the ducklings. Lead
was detected (greater than or equal to 0.02 p.p.m.) more frequently in
the blood of adult females than in adult males or ducklings and the m
aximum concentrations were 14.37, 0.50 and 4.28 p.p.m. wet weight, res
pectively. In adult females, there was a significant difference in the
proportion of detectable blood lead concentrations between three coll
ection times (arrival/nesting, hatch and brood rearing), with the high
est proportion (92%) occurring at hatch. Nine hens with blood lead con
centrations of greater than or equal to 0.50 p.p.m. were captured a se
cond time several weeks to 1 year later. In the hens sampled twice at
intervals of several weeks, the blood lead concentrations increased an
d declined at mean daily rates of 1.10 and 0.94, respectively. The lea
d concentrations in the blood of adults were not correlated with body
weights. Radiographs were taken of 119 eiders and corresponding blood
samples from 98 of these birds were analysed for lead. Ingested shot w
as seen in X-rays of 12 adults and three ducklings and, of the 13 bloo
d samples tested, all had detectable lead concentrations. Of the birds
without radiographic evidence of ingested shot, 84% of the adult fema
les, 19% of the adult males and 17% of the ducklings had detectable le
ad concentrations in their blood. Breeding ground exposure of waterfow
l to lead shot is unusual and is of particular concern in spectacled e
iders because of their threatened status and declining numbers in west
ern Alaska.