MERCURY
PATTERNS IN WOOD DUCK EGGS FROM A CONTAMINATED RESERVOIR IN SOUTH CAROLINA,
USA
ROBERT
A. KENNAMER,1 JASON R. STOUT,2 BRIAN P. JACKSON,1
SHEILA V. COLWELL,3 I. LEHR BRISBIN JR.,1 and JOANNA
BURGER2
1Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South
Carolina 29802, USA
2Ecology, Evolution, and Natural Resources, Division of Life
Sciences, and Environmental and Occupational Health Sciences Institute,
Rutgers University, Piscataway, New Jersey 08855, USA
3 National Park Service, Southeast Regional Office, Atlanta
Federal Center, 1924 Building, 100 Alabama Street SW, Atlanta, Georgia
30303, USA
(Received 4 December 2003; Accepted 18 January 2005)
Abstract-Mercury contamination of wildlife populations
has been documented widely in recent years as biomonitoring has become
an important tool for assessing environmental contamination. Avian eggs
provide an ideal assay material for Hg biomonitoring, particularly when
the collection of eggs is simplified by using cavity-nesting species that
nest in easily monitored nest boxes. However, studies are needed that
address the dynamics of how Hg is distributed within eggs, and how Hg
is deposited naturally within clutches laid by a single female and among
clutches laid by different females occupying the same contaminated environment.
We collected 138 eggs from 13 complete clutches of box-nesting wood ducks
(Aix sponsa) during 1991 and 1992 at a contaminated reservoir
of the U.S. Department of Energy's Savannah River Site in South Carolina,
USA. Total Hg residues in egg components and clutches were determined,
partitioning of Hg among egg components was examined, and effects of egg-laying
sequence on egg component Hg levels were determined. Mean albumen Hg was
0.22 ppm wet mass, mean yolk Hg was 0.04 ppm, and mean shell Hg was 0.03
ppm. On average, 86.1 % of total egg Hg was concentrated in the albumen,
11.2% in the yolk, and 2.7% in the shell. Mercury concentrations in all
egg components varied significantly among clutches and between successive
clutches laid by the same female in the same year. Laying sequence significantly
affected Hg concentrations in the albumen and shell, but not in the yolk.
Declines of albumen Hg due to laying sequence were more pronounced for
clutches that contained higher average Hg levels. Our results suggest
that collection of first-laid eggs may be preferable for assessing maximal
Hg exposure to developing embryos, and that monitoring Hg levels through
the use of empty eggshells following brood departure from nests may be
valid only if the laying sequence is known.
Keywords-Aix sponsa, Mercury, Egg-laying sequence,
Savannah River Site
SREL Reprint #2877
Kennamer, R. A., J. R. Stout, B. P. Jackson, S. V. Colwell, I. L. Brisbin, Jr. and J. Burger. 2005. Mercury patterns in wood duck eggs from a contaminated reservoir in South Carolina, USA. Environmental Toxicology and Chemistry 24:1793-1800.
