Several areas of the Great Lakes have been plagued by years of unregulated industrial waste dumping, resulting to a multitude of negative impacts on the wildlife and the environment.
Now, new research suggests that in order to maintain the Great Lakes' ecological health, two turtle species residing in Lake Michigan could act as ideal "pollution barometers."
Restoring The Great Lakes
A team of scientists led by Professor Gary Lamberti of the University of Notre Dame worked on a 10-year federal project to restore, assess and enhance the Great Lakes coastal wetlands.
The program, which was called the Great Lakes Restoration Initiative, assessed water quality, plants, fish, birds, invertebrates and amphibians. Reptiles have been excluded.
However, one of the researchers, Dayna Smith, suggested that they check for contaminants in turtles that were captured in fish nets.
And so they did. Lamberti, Smith and fellow researchers Matthew Cooper and Jessica Kosiara examined the liver, muscles, claws and shells of painted turtles and snapping turtles in four wetland locations.
Why turtles? Snapping turtles and painted turtles, which can live up to 50 years and 20 years old respectively, are common inhabitants of the coastal wetlands.
Lamberti and his team analyzed the animals for any traces of chromium, cadmium, iron, copper, manganese, magnesium, zinc and lead.
In the end, the team discovered that all turtle individuals they examined carried all of these eight metals.
In fact, concentrations of the metals in the animals' body even strongly correlated with analyses of metals in the soils of the wetlands.
Researchers also found that tests on the small samples of claw and shell yielded results similar to those from the liver and the muscle. This suggests that tests can be performed without having to kill the turtles.
Because of the lifespan of snapping turtles and painted turtles, as well as their relatively higher spot in the food chain compared to fish, these reptiles could actually be a great and useful source of measuring pollution in the wetlands, researchers said. They assert that turtles are valuable in monitoring contaminants and wetland ecosystems.
Meanwhile, Lamberti and his team warned that aside from being barometers for pollutants, snapping turtles could also pose health risks to humans who consume them. The risks are similar to the health advisories placed on fish found in the Great Lakes.
The study was funded by the U.S. Environmental Protection Agency and involved agencies and universities in the Great Lakes area. Details of the paper are published in the journal Environmental Monitoring and Assessment.
Photo: Joshua Mayer | Flickr