New York, Dec 5 (IANS): Dolphins living in Florida's Indian River Lagoon (IRL), and humans who live along the estuary and consume much of the same seafood as the dolphins were found to have high levels of mercury, according to a new research.

Initial studies of IRL dolphins showed high levels of mercury, which led Florida Atlantic University's Harbour branch scientists to conduct a follow-up study of humans who live in the same geographic area.

They found the cross-section of people tested also had high levels of mercury and that much of it was due to consumption of locally obtained fish and shellfish.

More than half of the participants in the study had a concentration of mercury in their hair, which was greater than the guideline for exposure defined by the US Environmental Protection Agency.

The most toxic form of mercury known as methylmercury builds up in fish, shellfish, and animals that eat fish, and are the main sources of mercury exposure in humans.

"This research exemplifies the role of dolphins as an animal sentinel in identifying a public health hazard," said Adam Schaefer, an epidemiologist at Florida Atlantic University-Harbour branch.

"It is a unique and critical example of closing the loop between animal and human health."

This is the first time that researchers have closed the loop between marine mammal and human health, by taking findings from their research and applying them to explore the potential risks facing humans living in the same region.

The findings of the study were published in the current issue of the journal Veterinary Sciences.

Mercury is a global health problem, most of which is due to consumption of fish and shellfish that become contaminated through the food web.