California – Researchers have identified the northern elephant seals‘ fur as a new source of mercury pollution in the water surrounding Año Nuevo, a state park in California. The coastal sites of this area contain 17 times more neurotoxic methylmercury during molting season than others without seals.

Scientists explain that when mercury, generated by industrial pollution, reach the ocean, microbes turn the chemical into a more dangerous compound called methylmercury. Thus, marine animals, even the ones from higher layers of the food chain, get contaminated with this compound when they are eating.

PNorthern Elephant Seal (Mirounga angustirostris), Piedras Blancas, San Simeon, CA. Photo by Michael "Mike" L. Baird. (Wikipedia)
Northern Elephant Seal (Mirounga angustirostris), Piedras Blancas, San Simeon, CA. Photo by Michael “Mike” L. Baird. (Wikipedia)

What scientists believe is that methylmercury can be passed through northern elephant seals’ excreta and fur during the molting season, which contributes to the high levels of mercury in the Californian coasts.

Lead of the study, Jennifer Cossaboon -an undergraduate at the University of California, Santa Cruz and a graduate student in Environmental Health at San Diego State University-, said that “elephant seals undergo a catastrophic moult (which) comes off in big sheets of fur and the top few layers of skin.”

These problems could be avoided if industries regulate their emissions from the burning of coal, an activity that has increased the amount of mercury in the marine environment two-to-four folder over preindustrial levels.

Why is it so important?

According to the US Environmental Protection Agency, people in the US are mainly exposed to methylmercury when they eat fish and shellfish that contains it. Almost all people have some amount of this toxic compound in their tissues, which reflects its widespread presence in the environment.

When children get exposed to methylmercury, the primary health effect is impaired neurological development.  Pregnant women who eat fish or shellfish that contains these compounds can affect their babies’ growing brain and nervous system.

Other effects like impairment of the peripheral vision; disturbances in sensations; lack of coordination of movements; impairment of speech, hearing, walking; and muscle weakness, are caused in humans exposed to methylmercury.

Source: EPA