Researchers monitoring the ecological health of the Great Lakes are looking to turtles for help.

The long lifespans of painted turtles and snapping turtles -- which can live as long as 20 and 50 years, respectively -- make the species ideal barometers of environmental health.

Turtles are relatively high on the food chain, which means toxins accumulate in turtles in measurable amounts. Scientists can monitor toxin levels in turtles over time as a proxy for environmental health among wetlands.

The Great Lakes, like most major water systems in the United States, have a long history of industrial pollution. A project called the Great Lakes Restoration Initiative -- newly organized by the U.S. Environmental Protection Agency and involving researchers from a variety of local universities -- aims to assess, enhance and restore wetlands along the coasts of the Great Lakes. But though the program calls for the monitoring of water quality, plants, invertebrates, fish, birds and amphibians, it ignores reptiles.

That may change, thanks to researchers at the University of Notre Dame who recently penned a scientific paper detailing the potential of turtles as a valuable environmental indicator species.

As part of their proof of concept work, researchers analyzed muscle, liver, shell, and claw samples collected from Lake Michigan turtles. The analysis revealed levels of cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc in concentrations similar to those measured in soil samples.

"Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems," researchers wrote in their paper.

Researchers say humans who consume snapping turtles should be careful, as they may be putting themselves at risk of contamination.