# How can methylmercury in the ocean be reabsorbed into the atmosphere?

The Sacramento Bee news article Toxic fog may be poisoning some of California’s mountain lions, study says says

Algae in the ocean convert mercury to methylmercury, its most toxic form, which can be reabsorbed into the atmosphere and come ashore as marine fog, the release says.

Methylmercury [CH3Hg]+ is an ion with an atomic mass well over 200. I don't think that it would readily evaporate, so how can it be reabsorbed into the atmosphere?

• – Fred
Dec 2 '19 at 8:13
• It is strange that the mercury should preferentially pick on mountain lions and then only on some mountain lions. Is it possible that the pollution comes from some other source peculiar to mountain lions? For example, could some of them be feeding on mercury contaminated fish? If I lived in California (my sister lives there),I would be more worried about my family than about mountain lions. Dec 2 '19 at 9:31
• @MichaelWalsby apex predators accumulate more. From the article "The study says mercury concentration increases 1,000 times for each step on the food chain, meaning mountain lions are at more risk than humans exposed to toxins in the fog." I suppose the "some mountain lions" are the ones eating animals that eat other things that have higher exposure. As long as your sister is not feeding her family on lichens from foggy areas, they may be okay.
– uhoh
Dec 2 '19 at 9:36

Much of the methyl mercury that enters the atmosphere may be dimethyl mercury, $$\text{(CH}_3\text{)}_2\text{Hg}$$. This is a very volatile compound which, if it were pure, would have 50 mm mercury or more vapor pressure at 20°C. Complexes involving more electronegative ligands, such as the chloride $$\text{CH}_3\text{HgCl}$$, are significantly less volatile, but still have more vapor pressure than purely inorganic mercury compounds.