July 12, 2025 Your Source for Brentwood News

Study: Toxic Chemical in Fog Killing Mountain Lions?

UC Santa Cruz study compares mercury concentrations of coastal and non-coastal mountain lions

By Sam Catanzaro

A new study recently conducted by researchers at the University of California, Santa Cruz suggests that toxic levels of mercury in fog may be poisoning mountain lions in coastal areas.

Researchers found that concentrations of mercury in mountain lions in the Santa Cruz Mountains were three times higher than in mountain lions outside the fog zone.

According to study leader Peter Weiss-Penzias, an environmental toxicologist who has worked extensively studying pollutants in coastal fog, while mercury levels in fog pose no threat to humans, the risk to terrestrial mammals may be more acute. With each level up the food chain, from lichen to deer to mountain lions, mercury concentrations can increase by at least 1,000 times says Weiss-Penzias.

“Lichen don’t have any roots so the presence of elevated methylmercury in lichen must come from the atmosphere,” Weiss-Penzias told UC Santa Cruz news. “Mercury becomes increasingly concentrated in organisms higher up the food chain.”

The study looked at fur and whisker samples from 94 coastal mountain lions and 18 noncoastal lions. Mercury concentrations in the coastal lions averaged around 1,500 parts per billion (ppb), while the noncoastal group averaged about 500 ppb.

An infographic showing the process by which mercury works it way up the food chain and ends up in the system of larger animals like mountain lions. Infographic courtesy Peter Weiss-Penzias.

Mercury enters the atmosphere through both mining and coal-fired power plants. While the study looked primarily at Central California mountain lions in the Santa Cruz Mountains — a region with a long legacy of prospecting and mercury mines — the study’s authors noted that close proximity to active or former mercury mines is not necessary for mercury to enter to the ecosystem via fog.

“Mercury is a global pollutant,” Weiss-Penzias said. “What’s emitted in China can affect the United States just as much as what’s emitted in the United States.”

In the Santa Monica Mountains, mountain lions are facing further difficulties intensified by an urban habitat. Since the National Park Service launched its study of mountain lions in the Santa Monica Mountains 17 years ago, five lions have died from rat poison.

Several other lions have been diagnosed with mange, which many researchers believe is linked to rat poisons, though they are unsure of the exact nature of the connection. Some think that the rat poisons weaken the animals’ immune system, making the cats more susceptible to mange.

In addition, several mountain lions have died after being struck by cars while attempting to cross highways and freeways. Those cats who do not cross the freeway are often forced to mate with their own offspring which leads to complications stemming from a smaller genetic pool. To address this, a nearly $100 million wildlife crossing bridge is slated to be completed by 2023 and stretch 200 feet above 10 lanes of the 101 freeway. The new wildlife crossing will give mountain lions of the Santa Monica Mountains safer access to food, open spaces and potential mates.

Related Posts

Downtown Santa Monica CEO Andrew Thomas to Step Down

July 12, 2025

July 12, 2025

Thomas, who rejoined DTSM, Inc. in 2022, oversaw the introduction of a private security program, expanded homeless outreach, and boosted...

Mayor Bass Issues Directive to Protect Immigrant Communities

July 12, 2025

July 12, 2025

The order expands access to city resources for affected families and requests records from ICE, including details on arrests Mayor...

(Video) Summer Camp at School of Rock West LA Turns Kids Into Rockstars

July 11, 2025

July 11, 2025

To Sign Up Now, Go To Schoolofrock.com Summer Camp at School of Rock West LA Turns Kids Into Rockstars To...

County Health Leaders Decry Federal Policy Barring Undocumented from Programs

July 11, 2025

July 11, 2025

The officials argued the policy jeopardizes care for all residents, noting it could deter people—regardless of status—from seeking treatment  Leaders...

LA Medical Center Seeks Help Identifying Unconscious Patient

July 11, 2025

July 11, 2025

He has been unconscious since admission, and staff have been unable to determine his identity Los Angeles General Medical Center,...

L.A. Louver Marks David Hockney’s 88th with Exhibit

July 11, 2025

July 11, 2025

Hockney, a British artist born in 1937, gained fame with the British Pop Art movement and later became known for...

California Seizes $476 Million in Illegal Cannabis

July 11, 2025

July 11, 2025

The operation, described as UCETF’s largest to date, involved support from multiple state agencies The state confiscated $476 million worth...

Suspect Arrested in Shoe Retail Theft Spree Across LA County

July 11, 2025

July 11, 2025

During the search, police recovered two firearms and a significant quantity of merchandise The Los Angeles Police Department’s Organized Retail...

For the Win Burger Chain Expanding to Brentwood: REPORT

July 10, 2025

July 10, 2025

Popular items include the double cheeseburger with bacon and jalapenos, as well as loaded fries topped with For The Win...

The Bar at Century Plaza to Celebrate National Caviar Day with Exclusive Tastings

July 10, 2025

July 10, 2025

The seven-hour event will feature exclusive caviar tastings and champagne pairings The Bar at Fairmont Century Plaza will host a...

Father-Daughter Authors to Host Book Signing to Aid Fire-Affected Women

July 10, 2025

July 10, 2025

Ten percent of proceeds from book and art sales will benefit the Pacific Palisades Rebuilding Fund, a nonprofit initiative created...

Metro Reports Crime Drop, Higher Rider Satisfaction, and Progress on Major Projects

July 9, 2025

July 9, 2025

The Authority said the drop in violent incidents—down to the lowest level since May 2019—coincided with more uniformed personnel and...

Angelini Grill Opens Limited Run at Peninsula Beverly Hills

July 9, 2025

July 9, 2025

The menu includes tableside Dover Sole, lobster salad, and a signature pasta tasting A new culinary collaboration, Angelini Grill, launched...

Jack Kirby Exhibit Opens at Skirball Cultural Center

July 9, 2025

July 9, 2025

The display features original comic illustrations, fine art, and commercial works, many shown publicly for the first time A new...

New Agenda Coaching: Changing Lives in LA

July 8, 2025

July 8, 2025

Students Work Toward Applied Success with Executive Function Coaching Services The demands of daily routines and studies sometimes bear weight...