Archive | December 2012

“Who’s polluting our fog??”

Tonight’s theme: Whodunit?(!)

Big Sur fog

The butler did it. (Image: Jane J. Lee — National Geographic)

Some foul villain has been contaminating the air in coastal California with that wonderfully toxic element, mercury! Water vapor in summer fogs in 2011 and 2012 was found to contain elevated mercury levels, and brave researchers from USC Santa Cruz set out with only their uh … fog-sampling equipment and other measurement tools … to find the culprit. From the temperate forests to the seaside, they tracked the toxin across the region until, after a terrifying* hunt, our heroes came face to face with the vicious polluter, who snarled defiance at them thusly:¬†“Ka-shwoosh.”

Because it was: the ocean.

No rly. The researchers measured the mercury levels in different strata of ocean water and decided that the increased mercury in coastal fog was caused by an upwelling of deep-ocean water, which then evaporated from the upper water layers and became fog.


No! Don’t panic! It’s okay! Peter Weiss-Penzias, the UC Santa Cruz toxicologist who led the investigation, was careful to note ¬†that even at these elevated levels, the amount of mercury in fog poses no health risk to humans — the increase his team found was at the scale of parts per trillion. However, a National Geographic article notes that increased deposition of mercury in fog could lead to bioaccumulation in dangerous concentrations in animal and plant tissues.

Now, before you go blaming the ocean for all your problems (“the ocean stole my prom date!” etc.), the Science Daily article mentions that this mercury might originally have come from … humans! Excessive mercury has been accumulating in the environment for more than a century (since the start of the Industrial Revolution), and it may have built up in ocean sediments and then been slowly transported to the surface via the global conveyor belt. I.e., this may be evidence of environmental impacts over a much longer time span than we’re used to thinking of.

Or maybe it was the butler.


*by which I mean “probably not that terrifying”