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Salton Sea is emitting foul-smelling hydrogen sulfide gas, triggering health concerns

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Salton Sea is emitting foul-smelling hydrogen sulfide gas, triggering health concerns

On scorching days when winds blow across the California desert, the Salton Sea regularly gives off a stench of decay resembling rotten eggs.

New research has found that the shrinking lake is emitting the foul-smelling gas hydrogen sulfide more frequently and at higher levels than previously measured.

The findings document how the odors from the Salton Sea add to the air quality problems and health concerns in communities near the lake, where windblown dust drifts from exposed stretches of lakebed and where people suffer from high rates of asthma and other respiratory illnesses.

“The communities around the Salton Sea are on the front lines of a worsening environmental health crisis,” said Mara Freilich, a co-author of the study and assistant professor in Brown University’s Department of Earth, Environmental and Planetary Sciences.

The Salton Sea is California’s largest lake, covering more than 300 square miles in Imperial and Riverside counties. Hydrogen sulfide is released as a byproduct of decaying algae and other organic material in the lake, where accumulating fertilizers and other nutrients from agricultural runoff and wastewater feed the growth of algae.

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Hydrogen sulfide, or H2S, is toxic and studies have found that health effects of exposure at certain levels can include dizziness, headaches, vomiting, cough, chest tightness and depression. Although being exposed to high levels in the workplace is a widely known health hazard, less is known about the health effects of chronic exposure to the gas at lower levels.

People who live near the Salton Sea, many of them farmworkers, have complained for years that the stench, which tends to emerge most strongly in August and September, can give them headaches, nausea and nosebleeds.

Freilich and other researchers analyzed existing air-quality data from three monitoring stations maintained by the South Coast Air Quality Management District in Indio, Mecca and the reservation of the Torres Martinez Desert Cahuilla Indians.

They worked with the local nonprofit group Alianza Coachella Valley to install an additional air-quality sensor on a wooden piling protruding from shallow water near the north shore. The sensor has often detected hydrogen sulfide at high levels.

Examining data from different monitoring sites between May 1 and July 25, 2024, they found a striking contrast. Although the monitor on the Torres Martinez reservation detected hydrogen sulfide at levels exceeding the state air-quality standard for only four hours during that time, the sensor over the water found 177 hours with levels above the threshold.

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The scientists said their results indicate that a significant portion of the gas that’s being released by the Salton Sea isn’t being measured, even as the stench drifts through the area’s predominantly Latino communities.

“These findings highlight the need for improved air quality monitoring and more effective environmental management policies to protect public health in the region,” the researchers wrote in the study, which was published May 31 in the journal GeoHealth.

The Salton Sea lies about 242 feet below sea level in the Salton Trough, which over thousands of years has cycled between filling with Colorado River water and drying out. The lake was formed most recently in 1905-07, when the Colorado flooded the region, filling the low-lying basin.

In the 1950s and ‘60s, the Salton Sea became a popular destination where tourists flocked to go fishing, boating and waterskiing. Celebrities including Frank Sinatra and Lucille Ball visited the lake during its heyday.

But lakeside communities deteriorated after flooding in the 1970s. Fishing waned as the lake grew too salty for introduced species such as corvina, and people stopped boating as the water quality worsened.

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The lake has for more than a century been sustained by water draining off farms in the Imperial Valley, but it has been shrinking since the early 2000s, when the Imperial Irrigation District began selling a portion of its Colorado River water to growing urban areas under an agreement with agencies in San Diego County and the Coachella Valley.

The lake’s level has declined about 13 feet since 2003. Its water is now about twice as salty as the ocean and continues to get saltier with evaporation. Bird populations have declined.

Hydrogen sulfide builds up in the lower, oxygen-deprived layer of water in the lake as decaying algae and other material decompose. During the hottest times of year, a warm upper layer of water forms. Then, when winds churn up the lake, some of the deeper water can rise to the surface and release the stinky gas into the air.

California’s ambient air-quality standard is 30 parts per billion, averaged over one hour. The study found that under certain wind conditions, hydrogen sulfide levels were on average 17 parts per billion higher at the newly installed sensor over the water compared with an existing monitor near the shore.

Sometimes, the sensor detected levels as high as about 200 parts per billion.

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People can detect the smell of the gas, however, at levels as low as 1 or 2 parts per billion.

“Residents exposed to hydrogen sulfide are impacted not only in their physical health — experiencing respiratory irritation, headaches and fatigue — but as well in their quality of life,” said Diego Centeno, the study’s lead author, who conducted the research while studying at Brown University and is now a doctoral student at UCLA.

“If you want to be active outside, go on a run or do something, and it smells like rotten eggs, you’d be more inclined not to,” Centeno said. “Especially during summertime, nobody wants to go outside.”

Centeno grew up within sight of the Salton Sea in the low-income community of North Shore. He said he was always fascinated by the immense body of water, not knowing why he never saw anyone bathing or boating in it.

“As water levels continue to decline, if nothing is done, this hydrogen sulfide gas really has the potential to grow,” Centeno said. “So the more we understand, the more we can learn how to mitigate and restore the Salton Sea.”

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The researchers said their findings highlight the need for increased air-quality monitoring around the Salton Sea, and for regulators to focus on hydrogen sulfide as a pollutant that affects people’s health.

Freilich said regional water regulators should prioritize setting of water-quality standards for the Salton Sea, a step that could lead to efforts to treat or reduce the nutrient levels of water flowing into the lake.

“The water quality in the sea is affecting the air quality,” she said. “It requires the attention of multiple agencies, because it is something that connects water quality and air quality, which are typically handled separately.”

The South Coast Air Quality Management District, or AQMD, regulates air pollution in the Coachella Valley, including the northern portion of the Salton Sea. In May, the agency installed a fourth monitor for hydrogen sulfide on the northeastern side of the lake.

“This H2S monitoring network is very comprehensive,” said Rainbow Yeung, an AQMD spokesperson, adding that there are currently only a few other monitors reporting such data in the country.

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Yeung said in an email that the sensor installed by the researchers is of a different type than the agency’s monitors and “may have higher H2S readings as the location of the sensor is over the source of likely emissions, which can be dispersed and therefore may not be representative of levels experienced by the community.”

AQMD issues alerts whenever hydrogen sulfide levels reach the state standard of 33 ppb at any of the monitoring sites. (Residents can sign up to receive these air-quality alerts at www.saltonseaodor.org.)

The California Office of Environmental Health Hazard Assessment has established a chronic exposure threshold for hydrogen sulfide of 8 parts per billion, a level at which long-term exposure over many years may begin to result in health effects.

The highest annual average concentration at any of the AQMD monitoring sites since 2016 has been 5.5 parts per billion, and annual averages have typically been less than 3 parts per billion, levels at which health effects are not expected, Yeung said.

The water that drains from Imperial Valley farmland and feeds the sea comes from the Colorado River. A quarter-century of mostly dry years compounded by climate change has prompted difficult negotiations among seven states over how to use less water from the dwindling river.

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As these talks examine water-saving solutions, Freilich said, policymakers should “account for the health impacts on communities” and prioritize steps that will help mitigate the problems.

California officials recently sent water flowing from a pipe onto hundreds of acres of dry lake bed near the south shore, filling a complex of shallow ponds in an effort to create wetland habitat for fish and birds, and help control lung-damaging dust.

It’s not known how these new wetlands might affect emissions of hydrogen sulfide, and Freilich said she and her team plan additional studies focusing on wetlands and shallow-water areas.

Consuelo Márquez, a Coachella resident who has helped with the research, said she lived for several years as a child in North Shore, where she got nosebleeds and experienced the rotten egg odor, a “really strong fishy smell.”

“I would wake up with blood on my pillow,” she said. When she asked her father about it, she recalled him saying: “This happens because of the lake, because of the air.”

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She said the study’s results validate the concerns many people have been raising for years.

Aydee Palomino, a co-author of the study and environmental justice project manager for the group Alianza Coachella Valley, said the study shows people are “breathing in pollutants that are under the radar of traditional monitoring systems.”

“This has the potential to have really far-reaching ramifications if it’s not addressed,” Palomino said.

Funding for the research came from the Burroughs Wellcome Fund, Google’s Environmental Justice Data Fund and NASA. But Freilich learned in March that the Trump administration had terminated the NASA grant under an order targeting diversity, equity and inclusion programs.

The researchers have an ongoing appeal of that decision, which Freilich said has been disruptive to ongoing work.

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“The community is who’s going to suffer at the end of the day,” Palomino said. “And it is unfortunate because now it comes back to us to fill in the research gaps.”

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Commentary: My toothache led to a painful discovery: The dental care system is full of cavities as you age

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Commentary: My toothache led to a painful discovery: The dental care system is full of cavities as you age

I had a nagging toothache recently, and it led to an even more painful revelation.

If you X-rayed the state of oral health care in the United States, particularly for people 65 and older, the picture would be full of cavities.

“It’s probably worse than you can even imagine,” said Elizabeth Mertz, a UC San Francisco professor and Healthforce Center researcher who studies barriers to dental care for seniors.

Mertz once referred to the snaggletoothed, gap-filled oral health care system — which isn’t really a system at all — as “a mess.”

But let me get back to my toothache, while I reach for some painkiller. It had been bothering me for a couple of weeks, so I went to see my dentist, hoping for the best and preparing for the worst, having had two extractions in less than two years.

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Let’s make it a trifecta.

My dentist said a molar needed to be yanked because of a cellular breakdown called resorption, and a periodontist in his office recommended a bone graft and probably an implant. The whole process would take several months and cost roughly the price of a swell vacation.

I’m lucky to have a great dentist and dental coverage through my employer, but as anyone with a private plan knows, dental insurance can barely be called insurance. It’s fine for cleanings and basic preventive routines. But for more complicated and expensive procedures — which multiply as you age — you can be on the hook for half the cost, if you’re covered at all, with annual payout caps in the $1,500 range.

“The No. 1 reason for delayed dental care,” said Mertz, “is out-of-pocket costs.”

So I wondered if cost-wise, it would be better to dump my medical and dental coverage and switch to a Medicare plan that costs extra — Medicare Advantage — but includes dental care options. Almost in unison, my two dentists advised against that because Medicare supplemental plans can be so limited.

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Sorting it all out can be confusing and time-consuming, and nobody warns you in advance that aging itself is a job, the benefits are lousy, and the specialty care you’ll need most — dental, vision, hearing and long-term care — are not covered in the basic package. It’s as if Medicare was designed by pranksters, and we’re paying the price now as the percentage of the 65-and-up population explodes.

So what are people supposed to do as they get older and their teeth get looser?

A retired friend told me that she and her husband don’t have dental insurance because it costs too much and covers too little, and it turns out they’re not alone. By some estimates, half of U.S. residents 65 and older have no dental insurance.

That’s actually not a bad option, said Mertz, given the cost of insurance premiums and co-pays, along with the caps. And even if you’ve got insurance, a lot of dentists don’t accept it because the reimbursements have stagnated as their costs have spiked.

But without insurance, a lot of people simply don’t go to the dentist until they have to, and that can be dangerous.

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“Dental problems are very clearly associated with diabetes,” as well as heart problems and other health issues, said Paul Glassman, associate dean of the California Northstate University dentistry school.

There is one other option, and Mertz referred to it as dental tourism, saying that Mexico and Costa Rica are popular destinations for U.S. residents.

“You can get a week’s vacation and dental work and still come out ahead of what you’d be paying in the U.S.,” she said.

Tijuana dentist Dr. Oscar Ceballos told me that roughly 80% of his patients are from north of the border, and come from as far away as Florida, Wisconsin and Alaska. He has patients in their 80s and 90s who have been returning for years because in the U.S. their insurance was expensive, the coverage was limited and out-of-pocket expenses were unaffordable.

“For example, a dental implant in California is around $3,000-$5,000,” Ceballos said. At his office, depending on the specifics, the same service “is like $1,500 to $2,500.” The cost is lower because personnel, office rent and other overhead costs are cheaper than in the U.S., Ceballos said.

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As we spoke by phone, Ceballos peeked into his waiting room and said three patients were from the U.S. He handed his cellphone to one of them, San Diegan John Lane, who said he’s been going south of the border for nine years.

“The primary reason is the quality of the care,” said Lane, who told me he refers to himself as 39, “with almost 40 years of additional” time on the clock.

Ceballos is “conscientious and he has facilities that are as clean and sterile and as medically up to date as anything you’d find in the U.S.,” said Lane, who had driven his wife down from San Diego for a new crown.

“The cost is 50% less than what it would be in the U.S.,” said Lane, and sometimes the savings is even greater than that.

Come this summer, Lane may be seeing even more Californians in Ceballos’ waiting room.

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“Proposed funding cuts to the Medi-Cal Dental program would have devastating impacts on our state’s most vulnerable residents,” said dentist Robert Hanlon, president of the California Dental Assn.

Dental student Somkene Okwuego smiles after completing her work on patient Jimmy Stewart, 83, who receives affordable dental work at the Ostrow School of Dentistry of USC on the USC campus in Los Angeles on February 26, 2026.

(Genaro Molina / Los Angeles Times)

Under Proposition 56’s tobacco tax in 2016, supplemental reimbursements to dentists have been in place, but those increases could be wiped out under a budget-cutting proposal. Only about 40% of the state’s dentists accept Medi-Cal payments as it is, and Hanlon told me a CDA survey indicates that half would stop accepting Medi-Cal patients and many others will accept fewer patients.

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“It’s appalling that when the cost of providing healthcare is at an all-time high, the state is considering cutting program funding back to 1990s levels,” Hanlon said. “These cuts … will force patients to forgo or delay basic dental care, driving completely preventable emergencies into already overcrowded emergency departments.”

Somkene Okwuego, who as a child in South L.A. was occasionally a patient at USC’s Herman Ostrow School of Dentistry clinic, will graduate from the school in just a few months.

I first wrote about Okwuego three years ago, after she got an undergrad degree in gerontology, and she told me a few days ago that many of her dental patients are elderly and have Medi-Cal or no insurance at all. She has also worked at a Skid Row dental clinic, and plans after graduation to work at a clinic where dental care is free or discounted.

Okwuego said “fixing the smiles” of her patients is a privilege and boosts their self-image, which can help “when they’re trying to get jobs.” When I dropped by to see her Thursday, she was with 83-year-old patient Jimmy Stewart.

Stewart, an Army veteran, told me he had trouble getting dental care at the VA and had gone years without seeing a dentist before a friend recommended the Ostrow clinic. He said he’s had extractions and top-quality restorative care at USC, with the work covered by his Medi-Cal insurance.

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I told Stewart there could be some Medi-Cal cuts in the works this summer.

“I’d be screwed,” he said.

Him and a lot of other people.

steve.lopez@latimes.com

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Diablo Canyon clears last California permit hurdle to keep running

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Diablo Canyon clears last California permit hurdle to keep running

Central Coast Water authorities approved waste discharge permits for Diablo Canyon nuclear plant Thursday, making it nearly certain it will remain running through 2030, and potentially through 2045.

The Pacific Gas & Electric-owned plant was originally supposed to shut down in 2025, but lawmakers extended that deadline by five years in 2022, fearing power shortages if a plant that provides about 9 percent the state’s electricity were to shut off.

In December, Diablo Canyon received a key permit from the California Coastal Commission through an agreement that involved PG&E giving up about 12,000 acres of nearby land for conservation in exchange for the loss of marine life caused by the plant’s operations.

Today’s 6-0 vote by the Central Coast Regional Water Board approved PG&E’s plans to limit discharges of pollutants into the water and continue to run its “once-through cooling system.” The cooling technology flushes ocean water through the plant to absorb heat and discharges it, killing what the Coastal Commission estimated to be two billion fish each year.

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The board also granted the plant a certification under the Clean Water Act, the last state regulatory hurdle the facility needed to clear before the federal Nuclear Regulatory Commission (NRC) is allowed to renew its permit through 2045.

The new regional water board permit made several changes since the last one was issued in 1990. One was a first-time limit on the chemical tributyltin-10, a toxic, internationally-banned compound added to paint to prevent organisms from growing on ship hulls.

Additional changes stemmed from a 2025 Supreme Court ruling that said if pollutant permits like this one impose specific water quality requirements, they must also specify how to meet them.

The plant’s biggest water quality impact is the heated water it discharges into the ocean, and that part of the permit remains unchanged. Radioactive waste from the plant is regulated not by the state but by the NRC.

California state law only allows the plant to remain open to 2030, but some lawmakers and regulators have already expressed interest in another extension given growing electricity demand and the plant’s role in providing carbon-free power to the grid.

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Some board members raised concerns about granting a certification that would allow the NRC to reauthorize the plant’s permits through 2045.

“There’s every reason to think the California entities responsible for making the decision about continuing operation, namely the California [Independent System Operator] and the Energy Commission, all of them are sort of leaning toward continuing to operate this facility,” said boardmember Dominic Roques. “I’d like us to be consistent with state law at least, and imply that we are consistent with ending operation at five years.”

Other board members noted that regulators could revisit the permits in five years or sooner if state and federal laws changes, and the board ultimately approved the permit.

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Deadly bird flu found in California elephant seals for the first time

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Deadly bird flu found in California elephant seals for the first time

The H5N1 bird flu virus that devastated South American elephant seal populations has been confirmed in seals at California’s Año Nuevo State Park, researchers from UC Davis and UC Santa Cruz announced Wednesday.

The virus has ravaged wild, commercial and domestic animals across the globe and was found last week in seven weaned pups. The confirmation came from the U.S. Department of Agriculture’s National Veterinary Services Laboratory in Ames, Iowa.

“This is exceptionally rapid detection of an outbreak in free-ranging marine mammals,” said Professor Christine Johnson, director of the Institute for Pandemic Insights at UC Davis’ Weill School of Veterinary Medicine. “We have most likely identified the very first cases here because of coordinated teams that have been on high alert with active surveillance for this disease for some time.”

Since last week, when researchers began noticing neurological and respoiratory signs of the disease in some animals, 30 seals have died, said Roxanne Beltran, a professor of ecology and evolutionary biology at UC Santa Cruz. Twenty-nine were weaned pups and the other was an adult male. The team has so far confirmed the virus in only seven of the dead pups.

Infected animals often have tremors convulsions, seizures and muscle weakness, Johnson said.

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Beltran said teams from UC Santa Cruz, UC Davis and California State Parks monitor the animals 260 days of the year, “including every day from December 15 to March 1” when the animals typically come ashore to breed, give birth and nurse.

The concerning behavior and deaths were first noticed Feb. 19.

“This is one of the most well-studied elephant seal colonies on the planet,” she said. “We know the seals so well that it’s very obvious to us when something is abnormal. And so my team was out that morning and we observed abnormal behaviors in seals and increased mortality that we had not seen the day before in those exact same locations. So we were very confident that we caught the beginning of this outbreak.”

In late 2022, the virus decimated southern elephant seal populations in South America and several sub-Antarctic Islands. At some colonies in Argentina, 97% of pups died, while on South Georgia Island, researchers reported a 47% decline in breeding females between 2022 and 2024. Researchers believe tens of thousands of animals died.

More than 30,000 sea lions in Peru and Chile died between 2022 and 2024. In Argentina, roughly 1,300 sea lions and fur seals perished.

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At the time, researchers were not sure why northern Pacific populations were not infected, but suspected previous or milder strains of the virus conferred some immunity.

The virus is better known in the U.S. for sweeping through the nation’s dairy herds, where it infected dozens of dairy workers, millions of cows and thousands of wild, feral and domestic mammals. It’s also been found in wild birds and killed millions of commercial chickens, geese and ducks.

Two Americans have died from the virus since 2024, and 71 have been infected. The vast majority were dairy or commercial poultry workers. One death was that of a Louisiana man who had underlying conditions and was believed to have been exposed via backyard poultry or wild birds.

Scientists at UC Santa Cruz and UC Davis increased their surveillance of the elephant seals in Año Nuevo in recent years. The catastrophic effect of the disease prompted worry that it would spread to California elephant seals, said Beltran, whose lab leads UC Santa Cruz’s northern elephant seal research program at Año Nuevo.

Johnson, the UC Davis researcher, said the team has been working with stranding networks across the Pacific region for several years — sampling the tissue of birds, elephant seals and other marine mammals. They have not seen the virus in other California marine mammals. Two previous outbreaks of bird flu in U.S. marine mammals occurred in Maine in 2022 and Washington in 2023, affecting gray and harbor seals.

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The virus in the animals has not yet been fully sequenced, so it’s unclear how the animals were exposed.

“We think the transmission is actually from dead and dying sea birds” living among the sea lions, Johnson said. “But we’ll certainly be investigating if there’s any mammal-to-mammal transmission.”

Genetic sequencing from southern elephant seal populations in Argentina suggested that version of the virus had acquired mutations that allowed it to pass between mammals.

The H5N1 virus was first detected in geese in China in 1996. Since then it has spread across the globe, reaching North America in 2021. The only continent where it has not been detected is Oceania.

Año Nuevo State Park, just north of Santa Cruz, is home to a colony of some 5,000 elephant seals during the winter breeding season. About 1,350 seals were on the beach when the outbreak began. Other large California colonies are located at Piedras Blancas and Point Reyes National Sea Shore. Most of those animals — roughly 900 — are weaned pups.

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It’s “important to keep this in context. So far, avian influenza has affected only a small proportion of the weaned at this time, and there are still thousands of apparently healthy animals in the population,” Beltran said in a press conference.

Public access to the park has been closed and guided elephant seal tours canceled.

Health and wildlife officials urge beachgoers to keep a safe distance from wildlife and keep dogs leashed because the virus is contagious.

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