Scientists have found a significant amount of mercury increasing in the fog in California coast. Comparing to the previous one, the new research found the mercury is increasing four times in just a few months.

Popular Science reported that in the American Geophysical Union's fall meeting, researchers discussed new evidence that the amount of coastal fog is not only increasing, but in some areas of California contains a surprising amount of a form of mercury called monomethylmercury. The meeting was held last week on December 16 and two researchers, Kenneth Coale from Moss Landing Marine Laboratories and Peter Weiss-Penzias from UC Santa Cruz reported the finding.

Monomethylmercury is the most worrying form of mercury. It is  the kind of mercury linked to severe health effects in humans, including kidney failure, birth defects, and neurological impairment.

However, the level of mercury found in the West coast's fog is still in the safe level for human, but it will cause a problem in the food chain as several animals were measured to have mercury levels above the accepted limit by FDA. During a press conference, Coale joked saying, "I would definitely not eat any spiders from foggy areas."

The research was funded by National Science Foundation (NSF) in a FogNet project, as a collaboration between researchers from various institutions: UCSC, Moss Landing Marine Labs, California State University-Monterey Bay, Humboldt State University Marine Laboratory, University of California, Davis, Bodega Bay Marine Laboratory, San Francisco State University, Pepperwood Preserve and the U.S. Geological Survey.

FogNet project will collect fog water during the summers of 2014 through 2016 for chemical characterization and quantification of fog deposition volume from seven locations along California coast. The project was initiated after a finding in American Geophysical Union's fall meeting in 2014, and in August this year the project found mercury level was five times higher than in the rain.

The number is increasing in several months, because according to CNBC, the concentration of mercury in fog are now 20 times higher than they are in rain, and the researchers estimate that plants and animals from foggy regions may have 10 times more mercury than those from other areas. Although it is not directly endangered human, but mercury in the fog will accumulate over time and become a source of pollutant, which will lead to a possible ecological effect.

Gizmodo reported the study also shows that the monomethylmercury is formed when dimethylmercury from smokestacks and mining processes finds its way into ocean waters and then, during certain weather conditions, into fog. Since fog is typically slightly acidic, the dimethylmercury reacts, creating monomethylmercury which is more easily deposited inland.

Mercury is a heavy metal neurotoxin that bioaccumulates and bioconcentrates as monomethyl mercury in water which is both water soluble and fat soluble. Fishes on the higher level of food chain such as tuna and mackerel may build up high level of mercury, making them unsafe for consumption.