1993. Mercury-Laden Fog Swirls Over Coastal California, Scientists Find

By National Science Foundation, August 26, 2015

Golden Gate Bridge draped in morning fog covering San Francisco Bay

What do the roof of a building in a West Coast redwood forest, a bluff in California chaparral, and a research vessel in Monterey Bay have in common?

They're often draped in tendrils of fog. That makes them prime sites for collecting fog water samples. And there's something else that can be found at those sites: mercury, according to atmospheric chemist Peter Weiss-Penzias of the University of California at Santa Cruz (UCSC).

Mercury: rolling in with fog

Sea fog is a significant, but previously overlooked, source of toxic monomethyl mercury deposited in coastal environments, Weiss-Penzias and colleagues reported at the December 2014, American Geophysical Union (AGU) Fall Meeting in San Francisco.

Their research is funded by the National Science Foundation (NSF)'s Chemical Oceanography Program in its Division of Ocean Sciences.

"'Fog drip' could deliver unsafe levels of monomethyl mercury to upland and near-shore ecosystems along the Pacific Coast," Weiss-Penzias says.

Other scientists had previously found high levels of mercury in Monterey Bay during coastal upwelling events--occasions when winds drive surface water offshore and colder water from the deep moves in to replace it. That gave Weiss-Penzias and colleagues the idea to find out whether mercury was somehow stealing ashore in fog.

Mercury is a heavy metal neurotoxin that bioaccumulates and bioconcentrates--primarily as monomethyl mercury--in aquatic food webs. It often reaches high levels in fish and other animals, making them unsafe for human consumption.

The source of monomethyl mercury in aquatic organisms has been debated, says Weiss, "but atmospheric deposition has been implicated as a pathway. Emissions such as coal combustion likely make a significant contribution."

That deposition affects all forms of precipitation: rain, snow and fog.

Weiss-Penzias and other researchers started their search by collecting fog samples by dark of night from June through August 2011.

They worked only in blackness so there would be no decomposition of mercury from sunlight, moving a single fog water collector among four locations near Santa Cruz: the roof of a UCSC building located in a redwood forest; a bluff at UCSC's Long Marine Laboratory; the Moss Landing Marine Labs' research vessel John H. Martin in Moss Landing Harbor; and an offshore spot in Monterey Bay where the John H. Martin was temporarily moored.

FogNet: a dragnet for mercury

The scientists then expanded their goals. Their NSF-funded project, called FogNet, involves sampling fog from seven locations along the California coast, from Eureka to Monterey.

FogNet is a collaborative effort among researchers at 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.

The project will collect fog water during the summers of 2014 through 2016 for chemical characterization and quantification of fog deposition volume, Weiss-Penzias says.

The new data show elevated monomethyl mercury concentrations, similar to those the team revealed at the December AGU conference, as well as in a paper published in 2012 in the AGU journal Geophysical Research Letters.

"The hypothesis we're now testing," Weiss-Penzias says, "is whether a form of mercury called dimethyl mercury produced in the coastal ocean can be incorporated into cloud droplets, then be deposited in ecosystems on land and become an important, or even dominant, contributor to monomethyl mercury there."

Fog samples are being collected at Marina Airport, Long Marine Laboratory, UCSC, Montara Lighthouse, Bodega Bay, Pepperwood Preserve, and Humboldt State University Marine Laboratory.

Hidden in the mist

The average monomethyl mercury concentration in the fog water samples taken in 2011 was five-fold greater than the previously reported highest monomethyl mercury levels in rain water.

"There haven't been reports of monomethyl mercury measurements in fog water in the scientific literature," says Weiss. "But these elevated concentrations suggest that fog could be a significant source in coastal environments."

Could fog be a vector for not only mercury, but other toxic elements?

"We really don't know," says Weiss. "The potentially far-reaching consequences of these results, however, underscore the need to collect fog water in various locations along the coast."

Weiss-Penzias has teamed with UCSC biologist Chris Wilmers for one of the next steps in the research. Wilmers is providing hair and whisker samples from mountain lions that roam the oft-foggy Santa Cruz Mountains and Sierra Nevada foothills, where mercury was used in the Gold Rush era due to its ability to extract the precious metal from other materials.

Early results show that whiskers from coastal mountain lions contain mercury levels that are, on average, 10 times higher than those of their inland counterparts.

"We're looking at whether the mercury is linked with plants eaten by the mountain lions' main prey--deer," says Weiss-Penzias.

The scientist says he's constantly looking for mercury. When he walks down his driveway to pick up the morning paper, he wonders what's in the dew.

"If my feet are wet when I get back in," he says, "I'm thinking: 'it was foggy enough last night to get a good sample."

===

Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov

InvestigatorsPeter Weiss-Penzias 

Related Institutions/OrganizationsUniversity of California-Santa Cruz

Related ProgramsChemical Oceanography 

Related Awards#1333738 Collaborative Research: Investigations on the Cycling of Mercury from the Ocean to Fog and Deposition to Land in Coastal California 

Total Grants$334,159

Related WebsitesFogNet: Fog Water Collection Network in Coastal California: http://fognet.ucsc.edu/

1633. Making Chemicals Green

By Rolf U. Halden and Robert S. Lawrence, The New York Times, November 9, 2014

Recent concerns with chemical manufacturing

FOR nearly 40 years, the Food and Drug Administration has wrestled with regulating the chemicals triclosan and triclocarban as they have become among the world’s most ubiquitous environmental contaminants. Designed to kill bacteria, they have been added to antibacterial soaps, cosmetics and other consumer products despite longstanding concerns about their impacts on humans and the environment.

The fact that they are still being used underscores the need to reform the nation’s regulatory system and manufacturing approach for chemicals.

We just completed an analysis of 143,000 peer-reviewed research papers to track the progress of what we call chemicals of emerging concern. We found that it takes around 14 years from the point at which safety issues are raised about a chemical before scientists’ concern peaks and regulators act.

In the case of triclosan and triclocarban, regulatory action has taken a lot longer, even though we know that these chemicals can interfere with the human endocrine system, affecting development and metabolism, and may also be contributing to antibiotic resistance in bacteria that cause human infections.

The F.D.A. considered removing the chemicals from some consumer products in 1974 but concluded that there was inadequate data on their safety and said that it would reconsider the issue in a year. A seemingly unending series of reviews followed. Then, last December, only after being sued by the Natural Resources Defense Council, the agency ordered makers of antibacterial soaps and body washes used with water to show by next month whether these chemicals are safe and effective — or to stop using them.
(This would not be a great loss; antibacterial soaps are no better at killing germs than ordinary soap and water.)

These chemicals belong to a class of persistent, bioaccumulative and toxic (PBT) compounds known as organohalogens. Perhaps the best known of these is DDT, a widely used pesticide banned in 1972 after devastating fish and bird populations (we still find remnants of it today in the blood of adults, children and newborns). While triclosan and triclocarban are not DDT, they share similarities that make them slow or impossible to degrade — their carbon-halogen bonds.

Regulators should also sharply curtail the use of two other classes of organohalogens: brominated organics, used primarily as flame retardants, and fluorinated compounds, used in food packaging, textiles and many consumer products.

We’ve known for decades that organohalogens pose potential hazards. The problem is, we don’t regulate chemicals by class, but individually, one compound at a time. And with about 84,000 chemical compounds in commercial use, and another 500 to 1,000 new ones introduced each year, we’ve created a situation that is impossible to regulate effectively.

Adding to the morass, two federal agencies, the F.D.A. and the Environmental Protection Agency, regulate chemicals depending on their use. The F.D.A. oversees chemicals that are ingested or used on the skin; the E.P.A. regulates the same chemicals when used for agriculture and industry. Little consideration is given to the potential health effects of chronic exposure to even small doses or to the effects of compounds that are likely to persist in the environment.

We have conducted over 30 peer-reviewed scientific studies on pollutant exposure and detected dozens of organohalogens in mothers and their babies; associated health effects include altered hormone levels, lower birth weight and reduced head circumference.

So what should we do?

We must make safety, health and sustainability priorities throughout the life cycle of chemicals: their design, production, use, disposal and degradation. “Waste” is foreign in nature; all material flow is circular. We need to convert our linear approach to chemical manufacturing into a circular one, in which all products have a planned end-of-life.
We should regulate chemicals as we understand them: in groups. Instead of regulating one compound at a time and only after decades of debate, we should manage classes of PBT chemicals. Organochlorines, organobromines and organofluorines in consumer products pose intrinsic risks that rise with each carbon-halogen bond.

Regulations should also encourage industry to make products from benign or “green” chemicals. These are composed of basic, ubiquitous building blocks, not ones that are rare in nature and incompatible with biodegradation. Safer options are feasible and available.

In September, an important step was taken. Senators Chris Coons, Democrat of Delaware; Susan Collins, Republican of Maine; Jay Rockefeller, Democrat of West Virginia; and Johnny Isakson, Republican of Georgia, proposed legislation that would encourage research and scientific collaboration in developing sustainable chemistry and create public-private partnerships to make and market sustainable chemical products.
Synthetic chemicals are vital to our society. But we should be doing everything possible to make sure they are safe.

Rolf U. Halden is an engineering professor and director of the Center for Environmental Security at Arizona State. Robert S. Lawrence is director of the Center for a Livable Future at Johns Hopkins.