Toxic fog could be poisoning California's mountain lions
Fog off the coast of California could be responsible for poisoning the state's mountain lions, according to a new study from the University of California Santa Cruz.
Researchers found marine fog mercury levels were three times higher in mountain lions living along the coast than those living inland.
Mercury is released in the atmosphere through mining and coal-fired power plants.
The toxins can cause neurological damage and decrease fertility. The study showed that fog-borne mercury is moving up the food chain starting with plants, then deer and mountain lions.
For their paper, researchers analyzed fur and whisker samples from 94 coastal mountain lions and 18 noncoastal lions. Mercury concentrations in the coastal samples averaged about 1,500 parts per billion (ppb), significantly larger than the 500 ppb measured in the noncoastal group.
"Fog is a stabilizing medium for methylmercury," says Peter Weiss-Penzias, an environmental toxicologist at UC Santa Cruz and lead author of the paper.
"Fog drifts inland and rains down in microdroplets, collecting on vegetation and dripping to the ground, where the slow process of bioaccumulation begins."
Researchers say the mercury levels in fog don't post a health risk to humans, but the risk to some mammal species could be significant.
"With each step up the food chain, from lichen to deer to mountain lions, mercury concentrations can increase by at least 1,000 times," Weiss-Penzias said.
