A recent study published in the Proceedings of the National Academy of Sciences found that the hair from Northern elephant seals (Mirounga angustirostris) contain the toxic metal mercury, according to Science News. When shed, this hair can increase the mercury levels of the surrounding seawater by 17 times, giving scientists yet another cause of mercury pollution.

The finding could be the answer to the mystery of why mercury pollution is so high in coastal areas where seal populations are at their highest.

"It's important to be aware of this phenomenon, just so we know where to identify those hot spots," says Jennifer Cossaboon, an environmental health researcher at San Diego State University and coauthor of the study.

Mercury is a toxic chemical that poses hazards to the marine environment due to the fact that it is quickly and readily absorbed into the bodies of marine organisms, according to Phys.org. Furthermore, it undergoes a process called "biomagnification" whereby the toxin becomes increasingly concentrated as it moves up the food chain.

"Many studies have looked at biomagnification up the food chain, and we took that a step further to see what happens next," said Cossaboon. "Mercury is an element, so it never breaks down and goes away - it just changes forms."

Mercury is currently two to four times higher than preindustrial levels, and its presence in the marine environment is expected to continue to increase for the next few decades, according to Takepart.