Northern Elephant Seals Are Shedding Mercury

Mercury, the same toxin spewed out from power plants, has now been found in the hair of Northern elephant seals. The discovery finally offers researchers an explanation as to why mussels found in the waters of Año Nuevo State Reserve contained 35 times more mercury than mussels found in other sites.

WHY ARE NORTHERN ELEPHANT SEALS HARBORING MERCURY?

According to Science News, seals tend to congregate on remote and pristine coastal areas. Yet, for some time, these sites, located miles away from power plants or other obvious sources of pollution, were found to contain usually high and even toxic amounts of the neurotoxin.

A new study, conducted by scientists at UC Santa Cruz, recently compared water samples taken from other sites with ones taken from the Año Nuevo State Reserve. The resulting samples revealed that sea water levels of methylmercury – a bioaccumulative environmental toxicant – can increase by as much as 17 times during molting season, when hair is shed from northern elephant seals, and twice as high during breeding season, according to a report in the Proceedings of the National Academy of Sciences, published on September 17.

WHERE DID ALL THIS MERCURY COME FROM?

Mercury is released into the environment due to burning coal. When some of the particles fall into the ocean, marine organisms, such as plankton, ingest it. Overtime, the metal begins to pass up the food chain in a process known as “biomagnification,” which causes the toxin to build up in concentration. As seals consume huge quantities of fish, the toxin is found at increasingly high levels in their bodies. During molting season, seals shed their top layers of skin – and along with it, the mercury, into the surrounding waters.

“Mercury is an element, so it never breaks down and goes away—it just changes forms,” states Jennifer Cossaboon, the leader of the study.

The statement is troubling as an 880-pound elephant lion can lose about 30 pounds of hair and skin. Taking this into consideration, a colony of 4,000 seals can shed roughly 120,000 pounds of mercury laden skin into the surrounding water, as reported by Yahoo News.

At this time, researchers are uncertain to what extent the mercury levels affect the elephant seals. What they do know is that nearly 99 percent of North Pacific elephant seals examined in a study had blood mercury levels that surpassed what is considered “the threshold for clinical neurotoxicity in humans.”

Cossaboon warns of the implications of this, as mercury levels are expected to keep climbing.

The best thing we can do is cut emissions—and also get educated about the fish we’re eating,” she states.


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