A latest research, published on Monday in Proceedings of the National Academy of Sciences, has suggested that the open ocean is shuttling a particularly toxic form of mercury into coastal areas in an unexpected way, in the fur of seals and sea lions.

Seawater gets polluted by mercury when mercury is absorbed from polluted air, or when it’s dumped in seawater by industrial sources along with other pollutants. Mercury is present in a number of chemical compounds, which are harmful if they succeed in getting into a body. But the scariest case is when it hits the ocean because of the way it interacts with certain marine organisms.

Seawater has tiny microbes that can convert mercury into a different form, known as ‘methylmercury’, which is a strong neurotoxin capable of harming a brain. When one of these microbes is consumed by animals, the methylmercury get transferred into its body and thus can be transferred from one predator to the next through the food chain, and finally reaching humans.

The research has suggested that methylmercury may be building up in some coastal areas for a different reason. Mercury is being carried in from the open ocean by contaminated seals. They shed it into the seawater through their fur.

Thus scientists need to keep an eye on methylmercury ‘hot spots’ in the ocean, which could lead to contaminated seafood. Methylmercury poisoning is said to be dangerous for pregnant women and young children.