Copper Could Contribute to Ozone Depletion, New Study Finds

Copper wire scraps are seen during the construction of the new R240 electric engine of French carmaker Renault at their factory in Cleon, France, June 18, 2015. (Reuters)
Copper wire scraps are seen during the construction of the new R240 electric engine of French carmaker Renault at their factory in Cleon, France, June 18, 2015. (Reuters)
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Copper Could Contribute to Ozone Depletion, New Study Finds

Copper wire scraps are seen during the construction of the new R240 electric engine of French carmaker Renault at their factory in Cleon, France, June 18, 2015. (Reuters)
Copper wire scraps are seen during the construction of the new R240 electric engine of French carmaker Renault at their factory in Cleon, France, June 18, 2015. (Reuters)

Copper released into the environment from fungicides may be contributing significantly to stratospheric ozone depletion, according to a new study from the University of California (UC).

In a paper published Jan. 14 in the journal Nature Communications, UC geochemists show that copper in soil and seawater acts as a catalyst to turn organic matter into both methyl bromide and methyl chloride, two potent halocarbon compounds that destroy ozone. Sunlight worsens the situation, boosting production of these methyl halides by a factor of 10. The findings answer, at least in part, a long-standing mystery about the origin of much of the methyl bromide and methyl chloride in the stratosphere.

Since the worldwide ban on chlorofluorocarbon (CFC) refrigerants and brominated halons used in fire extinguishers starting in 1989, these methyl halides have become the new dominant sources of ozone-depleting bromine and chlorine in the stratosphere. As the long-lived CFCs and halons slowly disappear from the atmosphere, the role of methyl halides increases.

"By 2050, we should be back to relatively normal ozone, but things like the continued emissions of methyl bromide and methyl chloride are road bumps in the road to recovery. Copper usage in the environment is projected to increase rapidly in the next few years, and this should be considered when predicting future halogen load and ozone recovery," said the paper's senior author, Robert Rhew, UC professor of environmental science and policy.

Earth's ozone layer is critical to protecting us from cancer-causing ultraviolet light from the sun, but chemicals containing chlorine and bromine -- such as CFCs and halons -- were found in the 1980s to destroy the ozone, creating thinner layers in the stratosphere that let in more of the dangerous radiation.

Despite a ban on production of CFCs and halons, the ozone layer has yet to repair itself.

The persistence of the ozone hole is, for the most part, due to the persistence of banned ozone-depleting compounds, which take decades to dissipate in the stratosphere. But some ozone-depleting chemicals are still being emitted.

Among the major contributors today are methyl chloride and methyl bromide. One atom of bromine is 50 times more destructive to ozone than one atom of chlorine.

Though methyl bromide is banned for use as an agricultural soil fumigant, it is still used as a pesticide for quarantine and pre-shipment of agricultural products. And methyl chloride is used as a chemical feedstock, although most of its emissions are believed to be from biomass burning or natural in origin. But the total amount of these methyl halides produced each year still do not add up to the observed yearly addition of these chemicals to the atmosphere, a fact that has puzzled scientists for more than 20 years.

About one-third of the methyl bromide and methyl chloride in the atmosphere comes from unknown sources, Rhew said. The new findings suggest that copper is an important, if not the major, source of the missing methyl bromide and methyl chloride.

"We've banned methyl bromide, but are other changes that we're making in the environment causing large emissions of this compound into the atmosphere? With the increase in the use of copper, it appears that copper-catalyzed production is an increasing source, as well," Rhew said.

First author and former UC doctoral student Yi Jiao, now a postdoctoral fellow at the University of Copenhagen in Denmark, noted that copper compounds are allowed on organic crops, a legacy of its use in farming since the 1700s, including as a major antifungal agent in the Bourdeax mixture used since the 1880s in France to prevent downy mildew on grapes. Copper contamination of soils is a major issue today in Europe because of this history, and the ozone-depleting power of copper is another cause for concern.

"With widespread use of copper in the environment, this potentially growing impact should be considered when predicting future halogen load and ozone recovery. Copper combined with soil and sunlight produce more methyl halides," said Jiao.



Cheeseburgers and Chicken So Far Fail to Entice a Rescue Dog Who’s Spent Weeks on the Run in Alaska 

This image provided by Skylar Young-Bayer shows a trail camera catching a glimpse of the dog Jackie near a trap on Tuesday, March 25, 2025, in Juneau, Alaska. (Skylar Young-Bayer via AP)
This image provided by Skylar Young-Bayer shows a trail camera catching a glimpse of the dog Jackie near a trap on Tuesday, March 25, 2025, in Juneau, Alaska. (Skylar Young-Bayer via AP)
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Cheeseburgers and Chicken So Far Fail to Entice a Rescue Dog Who’s Spent Weeks on the Run in Alaska 

This image provided by Skylar Young-Bayer shows a trail camera catching a glimpse of the dog Jackie near a trap on Tuesday, March 25, 2025, in Juneau, Alaska. (Skylar Young-Bayer via AP)
This image provided by Skylar Young-Bayer shows a trail camera catching a glimpse of the dog Jackie near a trap on Tuesday, March 25, 2025, in Juneau, Alaska. (Skylar Young-Bayer via AP)

In the days after wildfires devastated the Los Angeles area, a formerly stray dog named Jackie lucked into a new life. She was rescued from an overburdened shelter in Los Angeles County, where she faced possible euthanasia, and given a home far away in Juneau, Alaska.

But Jackie didn’t stay long.

The German shepherd-husky mix slipped her collar on the first day with her new family in mid-February and absconded to a pocket of forest. Since then, she has been living by her wits — eluding a trap that was set with food such as cheeseburgers or chicken by animal control workers and volunteers worried about her.

The forested area Jackie frequents is near a busy road. Further, black bears are starting to reemerge from hibernation, raising the potential the dog could have an unfortunate run-in. Volunteers have stopped putting out food and cat kibble to avoid attracting bears.

“Maybe this is what she wants, is to be free and feral like this,” said Thom Young-Bayer, a Juneau animal control officer. “It's not a safe way for her to live here.”

Young-Bayer and his wife, Skylar, have been searching in their free time, often at night, for the skittish canine, painstakingly trying to build trust with her. Jackie has been known to burrow into the soft moss on the forest floor for cover and to avoid looking directly into the Young-Bayers’ headlamps, making it hard to detect her eyes in the dark.

On videos Thom Young-Bayer has taken with his infrared camera, Jackie’s red heat signature resembles something out of the movie “Predator.”

On a recent day, Young-Bayer caught a fleeting glimpse of Jackie in the lush forest, her dark coat helping camouflage her movements among the stumps and roots. He surveyed the undergrowth and surroundings but came up empty — as did a nearby trap he had been monitoring for weeks.

When Young-Bayer returned to a trail where a fellow animal control officer had been waiting, he learned Jackie had trotted past on a frozen pond.

Lately Young-Bayer has been encountering Jackie on every visit. Young-Bayer says that's progress. Weeks ago, if Jackie saw someone, she would flee. He and his wife aren't trying to sneak up on the dog and want to help her feel safe, he said.

Juneau Animal Rescue, a local pet adoption agency that also handles animal control and protective services, has asked that people who see Jackie report their sightings. Given the dog's skittishness, officials want to limit those searching for her.

Little is known about Jackie's history. She was brought into a California shelter as a stray in early January, days before deadly wildfires swept through the Los Angeles area. She is believed to be 2 to 3 years old. Her intake forms listed her as quiet with a moderate anxiety and stress level.

Skylar Young-Bayer, who has volunteered with rescue groups in that region, helped arrange for Jackie and two other dogs at risk of being euthanized to be transferred to Juneau for adoption. Jackie was with a foster home before her adoption placing.

Other dogs have gained fame as fugitives, including Scrim, a 17-pound, mostly terrier mutt who was recaptured in New Orleans in February — in a cat trap — after months on the lam.

Mike Mazouch, animal control and protection director for Juneau Animal Rescue, noted Jackie didn't have much time to bond with her new family before bolting. Officers deemed trying to tranquilize her as too risky because they didn't know if they would be able to find her once she was sedated.

Mazouch accompanied Thom Young-Bayer to the forest last week to disassemble the trap when Jackie came within 50 feet (15 meters) of Mazouch on the frozen pond. Mazouch snapped a photo of her as she appeared between the skinny, tall trees. He called efforts to capture her a “battle of wills.”

“She is not willing to give up, and we're not willing to give up, either,” Mazouch said.