Comparison of mercury burdens in chronically debilitated and healthy loggerhead sea turtles (Caretta caretta).
An increase in the incidence of debilitated loggerhead sea turtle (Caretta caretta) strandings in the southeastern United States has been observed in recent years. These turtles are characterized by emaciation and heavy burdens of external and internal parasites, and bacterial infections, but the underlying cause of their condition is unknown. To investigate further the causes of these strandings, a health assessment was performed on stranded, debilitated loggerhead turtles, and contaminant concentrations in various tissues were compared to those from healthy turtles. This portion of the study investigated the potential role of mercury (Hg) toxicity in the debilitated condition described above. Hematocrit, total protein, albumin, globulin, glucose, calcium, lymphocyte counts, heterophil:lymphocyte ratios, aspartate aminotransferase, uric acid, sodium, and chloride were altered in debilitated loggerheads relative to healthy animals. However, none of the aforementioned health indicators correlated with Hg concentrations in either red blood cells (RBCs) or plasma. The Hg concentration in RBCs was 129+/-72 (mean+/-standard deviation) times higher than in plasma, causing a significant dilution of Hg in whole blood due to extreme anemia. Mercury concentrations in RBCs (73.7+/-21.2 ng/g) and scutes (455+/-57 ng/g) from debilitated turtles were similar to or lower than those reported for healthy animals, indicating no elevation in Hg exposure before and during the progression of this condition. These findings suggest that Hg toxicity does not play a role in the debilitated loggerhead condition observed in the southeastern United States.
Day
Rusty D
RD
National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Rd, Charleston, South Carolina 29412, USA. russell.day@nist.gov
Keller
Jennifer M
JM
Harms
Craig A
CA
Segars
Al L
AL
Cluse
Wendy M
WM
Godfrey
Matthew H
MH
Lee
A Michelle
AM
Peden-Adams
Margie
M
Thorvalson
Kelly
K
Dodd
Mark
M
Norton
Terry
T
D000818:Animals; D000835:Animals, Wild / Q000097:blood; D001267:Atlantic Ocean; D001772:Blood Cell Count / Q000662:veterinary; D001774:Blood Chemical Analysis / Q000662:veterinary; D001822:Body Burden; D016022:Case-Control Studies; D002908:Chronic Disease; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006304:Health Status; D006400:Hematocrit / Q000662:veterinary; D007107:Immune System / Q000187:drug effects; D008628:Mercury / Q000032:analysis* / Q000633:toxicity; D015144:Southeastern United States; D014018:Tissue Distribution; D014426:Turtles / Q000097:blood / Q000502:physiology; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000097:blood
D014874:Water Pollutants, Chemical; D008628:Mercury