Examining toxic trace element exposure in American alligators.

Area of Science:

• Environmental Science
• Toxicology
• Ecology

Background:

• Wetland ecosystems on the southeastern Atlantic coast have high mercury accumulation.
• Point sources of arsenic, cadmium, and lead also exist in this region.
• Monitoring trace element exposure requires accessible local sentinel species.

Purpose of the Study:

• To assess American alligators as sentinel species for human exposure to toxic trace elements.
• To measure concentrations of arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and other elements in alligators.
• To determine if alligator trace element levels correlate with human exposure risks.

Main Methods:

• Collected and analyzed trace element concentrations (As, Cd, Pb, Hg, Al, Ni, Cu, Zn, Se, Mo) in American alligators from seven wetland sites.
• Examined relationships between element concentrations and alligator sex, size/age, and site.
• Compared alligator trace element ranges to those reported in human populations.

Main Results:

• Site-specific differences were observed for As, Pb, Hg, Cd, Se, Zn, and Mo.
• Sex influenced Zn, Mo, and Al concentrations; size/age affected Hg and Pb.
• Observed ranges for As, Cd, Pb, and Hg in alligators were comparable to human levels.

Conclusions:

• American alligators can serve as a useful sentinel species for monitoring toxic element exposure in this region.
• Alligators provide a direct exposure pathway to humans through consumption.
• The similarity in trace element levels between alligators and humans highlights potential risks.