Detection of fog containing heavy metals

(towering) The towering rosewood forests along the California coast are known for the dense fog that rolls up from the ocean almost every night. Scientists have now discovered that these fogs contain mercury.

Previous studies have shown that fog sampled in and around Santa Cruz, California, contains mercury heavy metals, silver liquid found in old thermometers but no one knows the origin of Where does this mercury come from. New results presented at the American Geophysical Union conference in San Francisco on Dec. 4 show that mercury can be derived from the ocean.

"A small amount of mercury is not enough to harm people walking around in the fog - you can find mercury in tuna," says atmospheric chemist Peter Weiss-Penzias at the University of California, Santa Cruz. . 'However, fog is a big player in the water cycle of California's central coast. And since mercury accumulates in plants and animals, and accumulates more when it moves further in the food chain, the presence of this contaminant (mercury) poses a threat. to the ecosystem ".

Weiss-Penzias and his colleagues measured the concentration of dimethyl mercury seawater, an unstable gas form of mercury - at depths ranging from 3,300 feet (1,000 meters) to the surface of Monterey Bay in this spring. They discovered the highest concentration of dimethyl mercury around 660 feet deep (200 meters)."Over 200 meters, you penetrate where dimethyl mercury is less stable, so it decomposes and some of it escapes into the atmosphere ," Weiss-Penzias explained.

Combining this study with measurements shows that mist is a transport vehicle for 60 to 99% of all mercury transport from the air to the soil. Weiss-Penzias said he thought the ocean was the source of mercury in the case of California. He plans to collect measurements of dimethyl mercury in the atmosphere directly on the ocean to confirm his hypothesis and also wants to study other contaminants, including pesticides that could be brought in the cold of fog.

"There is a bit of mystery about the origin of mercury, but I think what we are seeing is a large-scale phenomenon that must be done with upwelling of deep seawater. along the coast, " Weiss-Penzias said in a statement.