It's been nearly 40 years since John Carpenter's cult-classic horror film, "The Fog," was unleashed upon the world, and it continues to haunt us in some unexpectedly realistic ways.

In the film, a deadly supernatural fog engulfs a California coastal town, killing all those who wander into its mist. Now it turns out this zany plot might actually contain more truth than fiction, and living in coastal communities everywhere might bear serious consequences.

A new study out of the University of California, Santa Cruz, has detected alarming levels of toxic mercury in California's coastal fog. The research is just the latest confirmation that this neurotoxin can be carried in fog, deposited on land, and found within the food chain, according to Phys.org.

The first warning sign occurred when researchers studying mountain lions in California's Santa Cruz Mountains measured dangerous concentrations of mercury in the cats' systems. At least one lion studied had mercury levels known to be toxic to species like mink and otters, and two others had "sublethal" levels that reduce fertility and reproductive success. A deeper look found that mercury contamination in coastal environments runs far deeper than what was found in the lions, though.

A study led by Peter Weiss-Penzias, an environmental toxicologist who has pioneered the study of pollutants in coastal fog, also found that mercury levels in lichen and deer were significantly higher inside the fog belt than beyond it. The correlation of elevated mercury levels with the fog zone made the source of the toxin obvious: it was in the fog.

"Lichen don't have any roots so the presence of elevated methylmercury in lichen must come from the atmosphere," said Weiss-Penzias. "Mercury becomes increasingly concentrated in organisms higher up the food chain."

The lichen get eaten by the deer, which get eaten by the mountain lions. Due to a process known as bioaccumulation, by the time the mountain lions get exposed, the mercury has been magnified by a significant degree. What begins as trace amounts of methylmercury in tiny water droplets floating through the air becomes life-threatening levels of deadly neurotoxin.

'What's in this stuff?'

In collecting data for this study, Weiss-Penzias recalled of his own tale and what led him into doing toxicology research on fog. Once, while riding his bike along the coast, he thought to himself: "I was riding through this absolute fogstorm, with water dripping off my glasses, and I just wondered, 'What's in this stuff?'"

When he collected samples and brought them into the lab for testing, the results surprised everyone. "The lab called me, saying they'd have to re-run the tests, because they didn't believe the numbers," he recalled.

While this latest study was performed on California's coastal ecosystems, researchers warn that what they found there can likely be found in coastal fog around the world. That's because the source of mercury in coastal fog is from the ocean, and the world's oceans have a fairly even distribution of this toxin across the planet.

The oceans aren't to blame, though; we are. The increased amount of mercury found in our oceans is directly connected with an increased amount of pollution generated from mining and coal-fired power plants around the world. "Mercury is a global pollutant," explained Weiss-Penzias. "What's emitted in China can affect the United States just as much as what's emitted in the United States."

An international treaty was adopted in 2013 to protect humans and the environment from mercury. It was called the Minamata Convention on Mercury, named after a Japanese city that suffered a terrible incident of mercury poisoning. Weiss-Penzias hopes that this latest research will bring attention to the fact that our coastal ecosystems are especially impacted by this dangerous toxin.

"It's important for the future of that treaty to understand all the different ways that mercury impacts the environment," he said.

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

An alarming amount of toxic mercury can now be found in coastal fog
Study found high levels of mercury in California's fog, but the problem likely extends around the world.