CONTAMINANTS AND DEBRIS
IN SEADUCKS
The health of seaducks is poorly understood and little is
known about contaminant levels in these marine animals. Seaducks can
be the primary animals impacted by ocean pollution and are susceptible
to ingestion or contamination by floating material. Therefore, it is
important to study the baseline health status of these animals and to
understand the likely impacts that result from marine debris. There are ongoing efforts to study
baseline contaminants in marine mammals through the NOAA marine mammal
program, and so this project will focus on seaducks.
The USGS collects seaducks for analyses of ingested food items. This project will examine other tissues for levels of contaminants. Evaluation of the quality and quantity of contaminants affecting seaduck has not been documented.
Clear documentation of contaminant loads in this population of
Atlantic seaducks has not been established. Gross external
examinations will include evaluation of obvious anomalies, overall
body condition, weight, and age. Internal gross examinations will
include evaluation of gross in situ organ appearance and sex
determination. Gizzard contents will be evaluated for identification
of foreign materials as part of another ongoing project looking at
food habits. Contaminants to be examined include heavy metals (tin,
mercury, selenium, cadmium) and PCBs (Arochlor 1254). Tributyltin is
found in anti-fouling paint used on ship hulls to prevent creatures
like barnacles from attaching, and accumulates in marine invertebrates
which are ingested by marine animals throughout the food chain.
Methylmercury is the most toxic form of mercury and the most
bioaccumulative.
It is also the most dominant form of mercury in fish. Burning of
fossil fuels with atmospheric deposition accounts for greater than 50%
of environmental mercury. Toxic effects can be found in kidneys and
reproductive organs and become endocrine disruptors. Selenium is an
essential, but potentially toxic element with a narrow margin of
tolerance in animals. It is also known to co-accumulate with mercury
and may actually enhance its toxic effects. Selenium in irrigation
water runoffs contribute to developmental problems and death of fish
and bird embryos.
Cadmium has increased in the environment primarily due to metal
smelting and burning of fossil fuels. It accumulates in sediments and
is a source of contamination of benthic organisms often ingested by
birds. Toxic signs in birds include kidney and reproductive organ
failure in addition to contributing to biochemical stressors resulting
in immunosuppression . Potential tissues to be collected for
contaminants include liver, kidney, muscle or brain. Tissues from the
above project will be utilized for contaminant analyses and results
will be made available to the federal agencies collaborating to supply
the carcasses for the project.
Tissue collection will be conducted from approximately 100 seaducks along the Atlantic seaboard. Analyses will be conducted at the Toxicology Laboratory at the Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA.