Wildfire ash could trap mercury

December 05, 2018

In the summers of 2017 and 2018, heat waves and drought conditions spawned hundreds of wildfires in the western U.S. And in November, two more devastating wildfires broke out in California, scorching thousands of acres of forest, destroying homes and even claiming lives. Now, researchers studying ash from recent California wildfires report in ACS' Environmental Science & Technology that burned material in forests might help sequester mercury that otherwise would be released into the environment.

Forest fires release substantial amounts of mercury into the atmosphere, but some mercury remains behind in wildfire ash. The fine, powdery nature of this material makes it prone to runoff into aquatic environments, where microbes can convert the element into highly toxic methylmercury. Yet the levels and fate of mercury in wildfire ash, which can be black or white in color, are unclear. Black ash is generated from low-intensity burning, whereas white ash results from higher burn intensities. Martin Tsz-Ki Tsui, Xiangping Nie and colleagues wanted to examine mercury levels and reactivity in black and white ash from two recent California wildfires.

When the researchers analyzed mercury levels, taking into account the amount of organic matter lost to combustion, they found that black ash, white ash and unburned vegetation from the wildfire areas contained similar amounts of mercury. However, most ash samples contained higher amounts of mercury that was in a chemically unreactive form than did the unburned samples. Stream water mixed with white or black ash for 4 or 12 weeks had lower amounts of mercury and methylmercury compared with water containing unburned vegetation. The researchers propose that black carbon, or charcoal, in the ash could bind mercury and keep it in a non-reactive form that is not released into water.
The authors acknowledge funding from the National Science Foundation, the National Institute of Food and Agriculture and UNC-Greensboro.

The paper's abstract will be available on December 5 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acs.est.8b03729

The American Chemical Society, the world's largest scientific society, is a not-for-profit organization chartered by the U.S. Congress. ACS is a global leader in providing access to chemistry-related information and research through its multiple databases, peer-reviewed journals and scientific conferences. ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies. Its main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.

Follow us: Twitter | Facebook

American Chemical Society

Related Mercury Articles from Brightsurf:

Mercury's 400 C heat may help it make its own ice
Despite Mercury's 400 C daytime heat, there is ice at its caps, and now a study shows how that Vulcan scorch probably helps the planet closest to the sun make some of that ice.

New potential cause of Minamata mercury poisoning identified
One of the world's most horrific environmental disasters--the 1950 and 60s mercury poisoning in Minamata, Japan--may have been caused by a previously unstudied form of mercury discharged directly from a chemical factory, research by the University of Saskatchewan (USask) has found.

New nanomaterial to replace mercury
Ultraviolet light is used to kill bacteria and viruses, but UV lamps contain toxic mercury.

Wildfire ash could trap mercury
In the summers of 2017 and 2018, heat waves and drought conditions spawned hundreds of wildfires in the western US and in November, two more devastating wildfires broke out in California, scorching thousands of acres of forest, destroying homes and even claiming lives.

Removing toxic mercury from contaminated water
Water which has been contaminated with mercury and other toxic heavy metals is a major cause of environmental damage and health problems worldwide.

Fish can detox too -- but not so well, when it comes to mercury
By examining the tissues at a subcellular level, the researchers discovered yelloweye rockfish were able to immobilize several potentially toxic elements within their liver tissues (cadmium, lead, and arsenic) thus preventing them from interacting with sensitive parts of the cell.

Chemists disproved the universal nature of the mercury test
The mercury test of catalysts that has been used and considered universal for 100 years, turned out to be ambiguous.

Mercury rising: Are the fish we eat toxic?
Canadian researchers say industrial sea fishing may be exposing people in coastal and island nations to excessively high levels of mercury.

New estimates of Mercury's thin, dense crust
Michael Sori, a planetary scientist at the University of Arizona, used careful mathematical calculations to determine the density of Mercury's crust, which is thinner than anyone thought.

Understanding Mercury's magnetic tail
Theoretical physicists used simulations to explain the unusual readings collected in 2009 by the Mercury Surface, Space Environment, Geochemistry, and Ranging mission.

Read More: Mercury News and Mercury Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.