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- Written by: Kathryn Crawford, Middlebury
The more scientists learn about the health risks of PFAS, found in everything from nonstick cookware to carpets to ski wax, the more concerning these “forever chemicals” become.
The U.S. Environmental Protection Agency now believes there is no safe level for two common PFAS – PFOA and PFOS – in drinking water, and it acknowledges that very low concentrations of other PFAS present human health risks. The agency issued the first legally enforceable national drinking water standards for five common types of PFAS chemicals, as well as PFAS mixtures, on April 10, 2024.
I study PFAS as an environmental health scientist. Here’s a quick look at the risks these chemicals pose and efforts to regulate them.
What exactly are PFAS?
PFAS stands for per- and polyfluoroalkyl substances. This is a large group of human-made chemicals – currently estimated to be nearly 15,000 individual chemical compounds – that are used widely in consumer products and industry. They can make products resistant to water, grease and stains and protect against fire.
Waterproof outdoor apparel and cosmetics, stain-resistant upholstery and carpets, food packaging that is designed to prevent liquid or grease from leaking through, and certain firefighting equipment often contain PFAS.
In fact, studies have found that most products labeled stain- or water-resistant contain PFAS, and another study found that this is even true among products labeled as “nontoxic” or “green.” PFAS are also found in unexpected places such as high-performance ski and snowboard waxes, floor waxes and medical devices.
At first glance, PFAS sound pretty useful, so you might be wondering what’s the big deal?
The short answer is that PFAS are harmful to human health and the environment.
Some of the very same chemical properties that make PFAS attractive in products also mean these chemicals will persist in the environment for generations. Because of the widespread use of PFAS, these chemicals are now present in water, soil and living organisms and can be found across almost every part of the planet, including Arctic glaciers, marine mammals, remote communities living on subsistence diets and in 98% of the American public.
The U.S. Geological Survey estimates common types of PFAS are now in at least 45% of the country’s tap water. PFAS maker 3M, facing lawsuits, announced a settlement worth at least US$10.3 billion in June 2023, with public water systems to pay for PFAS testing and treatment.
What are the health risks from PFAS exposure?
Once people are exposed to PFAS, the chemicals remain in their bodies for a long time – months to years, depending on the specific compound – and they can accumulate over time.
Research consistently demonstrates that PFAS are associated with a variety of adverse health effects. A review by a panel of experts looking at research on PFAS toxicity concluded with a high degree of certainty that PFAS contribute to thyroid disease, elevated cholesterol, liver damage, and kidney and testicular cancer.
Further, they concluded with a high degree of certainty that PFAS also affect babies exposed in utero by increasing their likelihood of being born at a lower birth weight and responding less effectively to vaccines, while impairing women’s mammary gland development, which may adversely affect a mom’s ability to breastfeed.
The review also found evidence that PFAS may contribute to a number of other disorders, though further research is needed to confirm existing findings: inflammatory bowel disease, reduced fertility, breast cancer, and an increased likelihood of miscarriage and developing high blood pressure and preeclampsia during pregnancy. Additionally, current research suggests that babies exposed prenatally are at higher risk of experiencing obesity, early-onset puberty and reduced fertility later in life.
Collectively, this is a formidable list of diseases and disorders.
Who’s regulating PFAS?
PFAS chemicals have been around since the late 1930s, when a DuPont scientist created one by accident during a lab experiment. DuPont called it Teflon, which eventually became a household name for its use on nonstick pans.
Decades later, in 1998, Scotchgard maker 3M notified the Environmental Protection Agency that a PFAS chemical was showing up in human blood samples. At the time, 3M said low levels of the manufactured chemical had been detected in people’s blood as early as the 1970s.
The Agency for Toxic Substances and Disease Registry has a toxicological profile for PFAS. And the EPA had issued advisories and health-based guidelines. But despite the lengthy list of serious health risks linked to PFAS and a tremendous amount of federal investment in PFAS-related research in recent years, PFAS hadn’t been regulated at the federal level in the United States until now.
The new drinking water standards set limits for five individual PFAS – PFOA, PFOS, PFNA, PFHxS and HFPO-DA – as well as mixtures of these chemicals. The standards are part of the EPA’s road map for PFAS regulations.
The EPA has also proposed listing nine PFAS as hazardous substances under the Resource Conservation and Recovery Act, a move that worries utilities and businesses that use PFAS-containing products or processes because of the expense of cleanup.
While waiting for federal action, states have taken their own steps to protect residents against the risk of PFAS exposure.
At least 28 states have laws targeting PFAS in various uses, such as in food packaging and carpets. About a dozen have drinking water standards for PFAS. But relying on state laws creates a patchwork of regulations, which places burdens on businesses and consumers to navigate regulatory nuances across state lines.
How can you reduce your PFAS exposure?
Based on current scientific understanding, most people are exposed to PFAS primarily through their diet, though drinking water and airborne exposures may be significant among some people, especially if they live near known PFAS-related industries or contamination.
The best ways to protect yourself and your family from risks associated with PFAS are to educate yourself about potential sources of exposure.
Products labeled as water- or stain-resistant have a good chance of containing PFAS. When possible, check the ingredients on products you buy and watch for chemical names containing “fluor-.” Specific trade names, such as Teflon and Gore-Tex, are also likely to contain PFAS.
Check whether there are sources of contamination near you, such as in drinking water or PFAS-related industries in the area. Strategies for monitoring and reporting PFAS contamination vary by location and PFAS source, so the absence of readily available information does not necessarily mean the region is free of PFAS problems.
For additional information about PFAS, check out the Agency for Toxic Substances and Disease Registry, EPA and U.S. Centers for Disease Control and Prevention websites, or contact your state or local public health department.
If you believe you have been exposed to PFAS and are concerned about your health, contact your health care provider. The National Academies of Sciences, Engineering, and Medicine have published guidance on PFAS exposure, testing and clinical follow-up, which includes information to help health care professionals understand monitoring and clinical implications of PFAS exposure.
This is an update to an article originally published June 21, 2022.
Kathryn Crawford, Assistant Professor of Environmental Health, Middlebury
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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- Written by: Elizabeth Larson
Dogs available for adoption this week include mixes of Alaskan husky, American blue heeler, Anatolian shepherd, border collie, German shepherd, hound, Labrador Retriever, pit bull terrier, Rottweiler and Weimaraner.
Dogs that are adopted from Lake County Animal Care and Control are either neutered or spayed, microchipped and, if old enough, given a rabies shot and county license before being released to their new owner. License fees do not apply to residents of the cities of Lakeport or Clearlake.
Those dogs and the others shown on this page at the Lake County Animal Care and Control shelter have been cleared for adoption.
Call Lake County Animal Care and Control at 707-263-0278 or visit the shelter online for information on visiting or adopting.
The shelter is located at 4949 Helbush in Lakeport.
Email Elizabeth Larson at
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- Written by: Chris Impey, University of Arizona
Stars like the Sun are remarkably constant. They vary in brightness by only 0.1% over years and decades, thanks to the fusion of hydrogen into helium that powers them. This process will keep the Sun shining steadily for about 5 billion more years, but when stars exhaust their nuclear fuel, their deaths can lead to pyrotechnics.
The Sun will eventually die by growing large and then condensing into a type of star called a white dwarf. But stars more than eight times more massive than the Sun die violently in an explosion called a supernova.
Supernovae happen across the Milky Way only a few times a century, and these violent explosions are usually remote enough that people here on Earth don’t notice. For a dying star to have any effect on life on our planet, it would have to go supernova within 100 light years from Earth.
I’m an astronomer who studies cosmology and black holes.
In my writing about cosmic endings, I’ve described the threat posed by stellar cataclysms such as supernovae and related phenomena such as gamma-ray bursts. Most of these cataclysms are remote, but when they occur closer to home they can pose a threat to life on Earth.
The death of a massive star
Very few stars are massive enough to die in a supernova. But when one does, it briefly rivals the brightness of billions of stars. At one supernova per 50 years, and with 100 billion galaxies in the universe, somewhere in the universe a supernova explodes every hundredth of a second.
The dying star emits high energy radiation as gamma rays. Gamma rays are a form of electromagnetic radiation with wavelengths much shorter than light waves, meaning they’re invisible to the human eye. The dying star also releases a torrent of high-energy particles in the form of cosmic rays: subatomic particles moving at close to the speed of light.
Supernovae in the Milky Way are rare, but a few have been close enough to Earth that historical records discuss them. In 185 A.D., a star appeared in a place where no star had previously been seen. It was probably a supernova.
Observers around the world saw a bright star suddenly appear in 1006 A.D. Astronomers later matched it to a supernova 7,200 light years away. Then, in 1054 A.D., Chinese astronomers recorded a star visible in the daytime sky that astronomers subsequently identified as a supernova 6,500 light years away.
Johannes Kepler observed the last supernova in the Milky Way in 1604, so in a statistical sense, the next one is overdue.
At 600 light years away, the red supergiant Betelgeuse in the constellation of Orion is the nearest massive star getting close to the end of its life. When it goes supernova, it will shine as bright as the full Moon for those watching from Earth, without causing any damage to life on our planet.
Radiation damage
If a star goes supernova close enough to Earth, the gamma-ray radiation could damage some of the planetary protection that allows life to thrive on Earth. There’s a time delay due to the finite speed of light. If a supernova goes off 100 light years away, it takes 100 years for us to see it.
Astronomers have found evidence of a supernova 300 light years away that exploded 2.5 million years ago. Radioactive atoms trapped in seafloor sediments are the telltale signs of this event. Radiation from gamma rays eroded the ozone layer, which protects life on Earth from the Sun’s harmful radiation. This event would have cooled the climate, leading to the extinction of some ancient species.
Safety from a supernova comes with greater distance. Gamma rays and cosmic rays spread out in all directions once emitted from a supernova, so the fraction that reach the Earth decreases with greater distance. For example, imagine two identical supernovae, with one 10 times closer to Earth than the other. Earth would receive radiation that’s about a hundred times stronger from the closer event.
A supernova within 30 light years would be catastrophic, severely depleting the ozone layer, disrupting the marine food chain and likely causing mass extinction. Some astronomers guess that nearby supernovae triggered a series of mass extinctions 360 to 375 million years ago. Luckily, these events happen within 30 light years only every few hundred million years.
When neutron stars collide
But supernovae aren’t the only events that emit gamma rays. Neutron star collisions cause high-energy phenomena ranging from gamma rays to gravitational waves.
Left behind after a supernova explosion, neutron stars are city-size balls of matter with the density of an atomic nucleus, so 300 trillion times denser than the Sun. These collisions created many of the gold and precious metals on Earth. The intense pressure caused by two ultradense objects colliding forces neutrons into atomic nuclei, which creates heavier elements such as gold and platinum.
A neutron star collision generates an intense burst of gamma rays. These gamma rays are concentrated into a narrow jet of radiation that packs a big punch.
If the Earth were in the line of fire of a gamma-ray burst within 10,000 light years, or 10% of the diameter of the galaxy, the burst would severely damage the ozone layer. It would also damage the DNA inside organisms’ cells, at a level that would kill many simple life forms like bacteria.
That sounds ominous, but neutron stars do not typically form in pairs, so there is only one collision in the Milky Way about every 10,000 years. They are 100 times rarer than supernova explosions. Across the entire universe, there is a neutron star collision every few minutes.
Gamma-ray bursts may not hold an imminent threat to life on Earth, but over very long time scales, bursts will inevitably hit the Earth. The odds of a gamma-ray burst triggering a mass extinction are 50% in the past 500 million years and 90% in the 4 billion years since there has been life on Earth.
By that math, it’s quite likely that a gamma-ray burst caused one of the five mass extinctions in the past 500 million years. Astronomers have argued that a gamma-ray burst caused the first mass extinction 440 million years ago, when 60% of all marine creatures disappeared.
A recent reminder
The most extreme astrophysical events have a long reach. Astronomers were reminded of this in October 2022, when a pulse of radiation swept through the solar system and overloaded all of the gamma-ray telescopes in space.
It was the brightest gamma-ray burst to occur since human civilization began. The radiation caused a sudden disturbance to the Earth’s ionosphere, even though the source was an explosion nearly 2 billion light years away. Life on Earth was unaffected, but the fact that it altered the ionosphere is sobering – a similar burst in the Milky Way would be a million times brighter.
Chris Impey, University Distinguished Professor of Astronomy, University of Arizona
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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- Written by: Lake County News reports
LAKE COUNTY, Calif. — The Berryessa Snow Mountain National Monument is expected to soon be expanded thanks to anticipated action by President Joe Biden.
The 330,780-acre monument — most of which is located in Lake County — is being considered for expansion through the addition of the Walker Ridge area.
That area, totaling 13,753 acres, will be referred to as “Molok Luyuk,” which means, “Condor Ridge,” in the Patwin language.
Reports came out of Washington, D.C. this week that President Biden plans to approve the monument’s expansion.
Biden was vice president when, on July 10, 2015, President Barack Obama — following an extensive campaign by state, local, tribal and federal representatives — designated the monument, which runs across the California Coastal Range in Colusa, Glenn, Lake, Mendocino, Napa, Solano and Yolo counties.
The rugged land boasts abundant wildlife, plants and other natural resources, and is a haven for outdoor recreation. It is managed by the Mendocino National Forest and the Bureau of Land Management.
Congressman Mike Thompson, Lake County’s longtime member of the House of Representatives, introduced the original legislation to designate Berryessa Monument back in 2015 and is the co-sponsor of the bill to expand the monument, as well.
"I worked to designate the Berryessa Snow Mountain region as a national monument in 2015, and I've worked to expand it ever since. The Monument's designation has played a crucial role in protecting the biodiversity of Northern California and an expansion of the Monument would have an immense positive impact on the region,” Thompson said.
While Biden’s action on the monument is pending, Sen. Bill Dodd, D-Napa, has a resolution urging the Berryessa Snow Mountain expansion which is set to be heard in a state Senate committee early next week.
“I thank the president for recognizing the incredible beauty and rich resources that make Berryessa Snow Mountain one of the most scenic and diverse landscapes in all of Northern California,” Sen. Dodd said. “It is vital to include this additional piece, which was home to native tribes for thousands of years. We can recognize the land’s cultural significance while protecting it for generations to come.”
In 2015, Sen. Dodd wrote Assembly Joint Resolution 4, the first time a state Legislature passed a measure asking the president to create a national monument. At that time, he was the Assembly member representing an area that included Lake County.
“I am proud to have been on hand when President Obama finalized the official designation,” Sen. Dodd said.
The designation arrives amid vanishing wild lands around the world. Nationwide, natural land is declining at a rate of one football field every 30 seconds, threatening plant and animal species and contributing to climate change, Dodd pointed out.
In response, both President Joe Biden and Gov. Gavin Newsom have championed the so-called 30X30 goal, which sets aside 30% of natural and coastal waters by 2030 to protect habitat, preserve history and maintain recreational opportunities.
Now, proposals before the president and Congress would expand Berryessa Snow Mountain Monument by 3,900 acres in Lake County.
They also support renaming the area commonly known as Walker Ridge to Molok Luyuk, reflecting the area’s cultural significance to many federally recognized tribes in the region.
By doing so, it would also provide opportunities for partnerships between the tribes, BLM and the U.S. Forest Service.
Sen. Dodd’s Senate Joint Resolution 10 helps fulfill state and federal goals by supporting federal approval of the monument’s expansion.
The state Senate Natural Resources committee is expected to endorse Sen. Dodd’s bill in a hearing on Monday.
Editor’s note: This story has been updated with additional information on the original legislation by Congressman Mike Thompson.