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Toxic chemical discovered in San Francisco’s fog

While the fog that often blankets the city of San Francisco is considered by many part of the city’s charm, some scientists now believe it may also be toxic. Recent studies show that as the fog moves in, it leaves behind a neurotoxin called monomethyl mercury. The deposit of monomethyl mercury is estimated to be at a rate of about 20 times more than that of San Francisco’s rainfall.  The concern is not of simply coming in contact with the fog, because “On a relative scale, the levels of mercury are quite low and of no health concern” according to Peter Weiss-Penzias of UC Santa Cruz. Instead the concern is “bioaccumulation”, meaning the toxin builds up in organisms over a long period of time. In fact, the study found that “Animals and plants in foggy regions may contain as much as 10 times the level of the mercury compound as life in less-foggy areas”. Wolf spiders were one such example. Researchers found wolf spiders in the area had higher levels of mercury than the FDA’s “3 parts per million safety threshold”. Again though, the concern is not that Americans will consume spiders, it’s that they are part of the food chain and their higher mercury levels will eventually reach us. In order to combat the concerns, researchers would like to see mercury emissions limited, especially when it comes to “coal-fired power plants”.

To learn more about the mercury levels in San Francisco’s fog, follow the link: