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kassy

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Persistent chemical pollution
« on: August 03, 2022, 07:31:36 PM »
The Consequences of using plastics threads contains a number of reports on chemical pollution related to them and there are scattered reports in some places but now it seems to become quite a big problem on it´s own although off course it is coming from the same roots, eg concentrated wealth making sure we live well beyond our means.

I had a newspaper article about a report but that broke so here is just the report:

Forbidden fruit: The dramatic rise in dangerous pesticides found on fruits and vegetables sold in Europe and evidence that governments are failing their legal obligations
European citizens have been exposed to a dramatic rise in the frequency and intensity of  residues of the most toxic pesticides on fruits and vegetables sold in the EU. This report and its primary conclusion contradict official claims that toxic pesticide use is declining and expose a complete failure by Member States to implement EU Regulation and protect consumers.

https://www.pan-europe.info/resources/reports

And today there was this:

Pollution: 'Forever chemicals' in rainwater exceed safe levels

New research shows that rainwater in most locations on Earth contains levels of chemicals that "greatly exceed" safety levels.

These synthetic substances called PFAS are used in non-stick pans, fire-fighting foam and water-repellent clothes.

Dubbed 'forever chemicals', they persist for years in the environment.

Such is their prevalence now that scientists say there is no safe space on Earth to avoid them.

The researchers from Stockholm University say it is "vitally important" that the use of these substances is rapidly restricted.

Scientists fear PFAS may pose health risks including cancer, though research has so far been inconclusive. They have been growing increasingly concerned about the proliferation of PFAS in recent years.

PFAS stands for poly- and perfluoroalkyl substances.

There are around 4,500 of these fluorine-based compounds and they are found in almost every dwelling on Earth in hundreds of everyday products including food packaging, non-stick cookware, rain gear, adhesives, paper and paints.

This new study, which looks at four specific chemicals in the class, suggests that levels of one PFAS in rainwater around the globe often "greatly exceed" US drinking water advisory levels.

Soil around the world is similarly contaminated, evidence suggests.


The study's findings lead the authors to conclude that a planetary boundary has been crossed - that there simply is no safe space on Earth to avoid these substances.

"We argue here that we're not within this safe operating space anymore, because we now have these chemicals everywhere, and these safety advisories, we can't achieve them anymore," said Prof Ian Cousins, the lead author from Stockholm University.

"I'm not saying that we're all going to die of these effects. But we're in a place now where you can't live anywhere on the planet, and be sure that the environment is safe."

While this is undoubtedly cause for concern, there are some provisos.

Many of these safety levels in place are advisory, meaning they are not legally enforceable.

Other scientists take the view that action on these chemicals should wait until the health risks are more clearly proven.

Much research has been carried out on the health risks posed by PFAS, and scientists say that exposure to high levels may be associated with an increased risk of some cancers, fertility issues and developmental delays in children.

However such associations don't prove cause and effect and other studies have found no connection between PFAS and disease.

But for those who have spent years working closely with PFAS, the evidence in the new research paper underlines the need for a precautionary approach.

"In this background rain, the levels are higher than those environmental quality criteria already. So that means that over time, we are going to get a statistically significant impact of those chemicals on human health," said Prof Crispin Halsall from the University of Lancaster. He was not involved with the Swedish study.

"And how that will manifest itself? I'm not sure but it's going come out over time, because we're exceeding those concentrations which are going to cause some harm, because of exposure to humans in their drinking water."

Removing the chemicals in the study from drinking water at treatment plants is possible, if expensive.

But getting below the US advisory levels is extremely challenging, according to the authors.

As scientists have gained more knowledge about PFAS over the past 20 years, the safety advisories have been continuously lowered.

The has also happened with regard to the presence of these chemicals in soil - and that too is causing problems.

In the Netherlands in 2018, the infrastructure ministry set new limits on concentrations of PFAS in soil and dredging material.

But this caused 70% of building projects involving soil removal or using excavated material to be halted. After protests, the government relaxed the guidelines.


According to the new study, this type of relaxation of safety levels is likely to happen with water contamination as well.

"If you applied those guidelines everywhere, you wouldn't be able to build anywhere," said Prof Ian Cousins.

"I think they'll do the same thing with the US drinking water advisories, because they're not practical to apply.

"It's not because there's anything wrong with the risk assessment. It's just because you can't apply those things. It's just impossible, from an economic viewpoint to apply any of those guidelines."

The key challenge with these chemicals is their persistence, rather than their toxicity, say the study authors.

While some harmful PFAS were phased out by manufacturers two decades ago, they persist in water, air and soil.

One way PFAS cycle through the environment is in the form of tiny particles carried in sea spray into the air and then back to land.

This inability to breakdown in the environment means that PFAS are now found even in remote areas of the Antarctic, as reported by Prof Halsall recently.

...

https://www.bbc.com/news/science-environment-62391069
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kassy

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Re: Persistent chemical pollution
« Reply #1 on: August 03, 2022, 09:17:47 PM »
New Antarctic study shows levels of 'forever chemicals' reaching the remote continent have been increasing

New evidence from Antarctica shows that toxic 'fluorinated forever chemicals' have increased markedly in the remote environment in recent decades and scientists believe CFC-replacements could be among likely sources.

Known as forever chemicals because they do not break down naturally in the environment, chemicals such as perfluorocarboxylic acids (PFCAs) have a wide array of uses such as in making non-stick coatings for pans, water-repellents for clothing, and in fire-fighting foams. One of these chemicals, perfluorooctanoic acid (PFOA), bioaccumulates in foodwebs and is toxic to humans with links to impairment of the immune system and infertility.

In this new study, published by the journal Environmental Science & Technology, and led by scientists from Lancaster University along with researchers from the British Antarctic Survey and the Hereon Institute of Coastal Environmental Chemistry, Germany, firn (compacted snow) cores were taken from the extremely remote, high and icy Dronning Maud Land plateau of eastern Antarctica.

The cores, which provide a historic record between 1957 and 2017, provide evidence that levels of these chemical pollutants have shown a marked increase in the remote snowpack of Antarctica over the last few decades.

The most abundant chemical discovered by far was the shorter chain compound, perfluorobutanoic acid (PFBA). Concentrations of this chemical in the snow cores increased significantly from around the year 2000 until the core was taken in 2017.

Professor Crispin Halsall of Lancaster University, and who led the study, believes this increase can be partly explained by a switch by global chemicals manufacturers around 20 years ago from producing long-chain chemicals like PFOA to shorter-chain compounds, such as PFBA due to health concerns associated with human exposure to PFOA.

Dr Jack Garnett who conducted the chemical analysis on the snow samples, added: "The large increase in PFBA observed from the core, particularly over the last decade, suggests there is an additional global source of this chemical other than polymer production. We do know that some of the chemicals replacing the older ozone-depleting substances like CFCs and HCFCs, such as the hydrofluoroethers, are produced globally in high quantities as refrigerants but can breakdown in the atmosphere to form PFBA.

"The Montreal Protocol certainly provided huge benefits and protection to the ozone, the climate and to us all. However, the wider environmental and toxicity impact of some of these replacement chemicals is still unknown."

PFOA shows an increase in the snow core from the mid-1980s onward, but with no evidence of a decline in more recent years to match the global industry phase out of this chemical. This indicates that production of PFOA was maintained or that volatile precursors to this chemical have remained high in the global atmosphere.

The researchers behind the study believe the chemicals are likely reaching Antarctica by the release of volatile 'precursor' chemicals into the atmosphere at industrial manufacturing sites. These precursors waft in the global atmosphere until they eventually degrade in the presence of sunlight to form the more persistent PFCAs.

Successive snowfall over the years has deposited these chemicals from the atmosphere resulting in a historical record of global contamination that is now trapped in the snow pack.

The results, which are consistent with modelled estimates of PFCA chemical emissions, further add to evidence that show increases in these forever chemicals in the Arctic and the Tibetan Plateau and helps provide a global picture and further understanding of how chemicals such as these are transported in the atmosphere.

...

https://www.sciencedaily.com/releases/2022/07/220728143011.htm
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kassy

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Re: Persistent chemical pollution
« Reply #2 on: August 03, 2022, 09:23:29 PM »
Exposure to 'forever chemicals' costs US billions in health costs

Daily exposure to a class of chemicals used in the production of many household items may lead to cancer, thyroid disease, and childhood obesity, a new study shows. The resulting economic burden is estimated to cost Americans a minimum of $5.5 billion and as much as $63 billion over the lifetime of the current population.

The new work revolves around per- and polyfluoroalkyl substances (PFAS), a group of over 4,700 humanmade chemicals that experts have detected for decades in the blood of millions of people. The chemicals are used, for example, in the production of water- and oil-resistant clothing, electronics, and nonstick cookware, and people are thought to ingest them as food comes into contact with packaging. The substances are believed to disrupt the function of hormones, signaling compounds that influence many bodily processes.

Led by researchers at NYU Grossman School of Medicine, the new study in roughly 5,000 Americans identified 13 medical conditions that may result from PFAS exposure, such as infertility, diabetes, and endometriosis, a painful disorder of the uterus. Together, the diseases generate medical bills and reduce worker productivity across a lifetime to create the costs measured by the study, say the study authors.

"Our findings add to the substantial and still-mounting body of evidence suggesting that exposure to PFAS is harming our health and undermining the economy," says study co-author Linda Kahn, PhD, MPH, an assistant professor in the Departments of Pediatrics and Population Health at NYU Langone Health.

Previous investigations have quantified the medical burden and financial costs of low birth weight due to PFAS exposure. However, the new study, publishing online July 26 in the journal Exposure and Health, incorporates a much broader range of health consequences across the lifespan, says Kahn.

For the investigation, the researchers determined how many Americans were likely exposed to PFAS chemicals in 2018 using blood samples obtained from adults and children who participated in the U.S. National Health and Nutrition Examination Survey. Next, the study team analyzed data from dozens of studies in the past decade that explored diseases connected to the substances.

The research team used models from earlier investigations to estimate the national economic cost of the medical bills and lost worker productivity that resulted from the top five medical conditions that had the strongest links to PFAS exposure. These included low birth weight, childhood obesity, kidney and testicular cancers, and hypothyroidism.

Among the findings, the investigation revealed that childhood obesity was the largest contributor to the overall economic toll of PFAS exposure, costing about $2.7 billion. Hypothyroidism in women, a condition in which the thyroid cannot release enough hormones into the bloodstream, was the next highest contributor at $1.26 billion.

The study investigators also expanded the scope of their economic estimates to include eight other conditions with preliminary links to PFAS exposure, including endometriosis, obesity in adults, and pneumonia in children. When such diseases were considered, the total costs reached as high as $63 billion.

"Our results strongly support the recent decision by the Environmental Protection Agency to lower the safe allowable level of these substances in water," says study senior author Leonardo Trasande, MD, MPP. "Based on our estimates, the cost of eradicating contamination and replacing this class of chemical with safer alternatives is ultimately justified when considering the tremendous economic and medical risks of allowing them to persist in the environment."

...

https://www.sciencedaily.com/releases/2022/07/220726132528.htm
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vox_mundi

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Re: Persistent chemical pollution
« Reply #3 on: August 05, 2022, 08:42:18 PM »
History of DDT Ocean Dumping Off LA Coast Even Worse Than Expected, EPA Finds
https://www.latimes.com/environment/story/2022-08-04/ddt-ocean-dumping-in-l-a-even-worse-than-expected
https://phys.org/news/2022-08-history-ddt-ocean-dumping-la.html

After an exhaustive historical investigation into the barrels of DDT waste reportedly dumped decades ago near Catalina Island, federal regulators concluded that the toxic pollution in the deep ocean could be far worse—and far more sweeping—than what scientists anticipated.

In internal memos made public recently, officials from the U.S. Environmental Protection Agency determined that acid waste from the nation's largest manufacturer of DDT—a pesticide so powerful it poisoned birds and fish—had not been contained in hundreds of thousands of sealed barrels.

https://www.epa.gov/system/files/documents/2022-07/epa-memo-initial-findings-regarding-ocean-disposal-of-montrose-chemical-acid-waste-2021-04-20.pdf

Most of the waste, according to newly unearthed information, had been poured directly into the ocean from massive tank barges.

Although shipping records noted the number of discarded barrels, regulators say the word "barrel" appeared to refer to a unit of volume, rather than a physical barrel. Further review of old records revealed that other chemicals—as well as millions of tons of oil drilling waste—had also been dumped decades ago in more than a dozen areas off the Southern California coast.

https://www.epa.gov/ocean-dumping/southern-california-ocean-disposal-site-2-investigation

"That's pretty jaw-dropping in terms of the volumes and quantities of various contaminants that were dispersed in the ocean," said John Chesnutt, a Superfund section manager who has been leading the EPA's technical team on the investigation. "This also begs the question: So what's in the barrels? … There's still so much we don't know."

These revelations build on much-needed research into DDT's toxic—and insidious—legacy in California. As many as half a million barrels of DDT waste have not been accounted for in the deep ocean, according to old reports and a UC Santa Barbara study that provided the first real glimpse into how the Los Angeles coast became a chemical dumping ground.

The scope of the pollution has turned out to be startling. In the process of trying to figure out how much DDT was dumped into the deep ocean, regulators discovered that from the 1930s to the early 1970s, 13 other areas off the Southern California coast had also been approved for dumping of military explosives, radioactive waste, and various chemical and refinery byproducts—including 3 million metric tons of petroleum waste.

Very little is known about these deep-water disposals beyond a grainy map from a 1973 technical report that labeled each dumpsite with a tiny dot or square.



https://www.documentcloud.org/documents/7212619-Ocean-Dumping-Under-Los-Angeles-Regional-Water

"The fact that here we are, more than 50 years later, and we don't even know what's in the 14 dumpsites other than a summary from a report in 1973 from the Southern California Coastal Water Research Project? That's just not acceptable," said Mark Gold, who has followed the DDT problem as a marine scientist since the 1990s and currently serves as Newsom's deputy secretary for coastal and ocean policy. "It really makes you question: OK, how big of a problem is deep-water ocean dumping … along not just the California coast, but nationwide?"

... Records also indicate there might actually be two DDT dumpsites, dubbed Dumpsite 1 and Dumpsite 2, because the company in charge of the disposal may have decided to dump in an area different from where it was supposed to.

The dumping appears to be sloppy: The Scripps expedition spent two weeks mapping a swath of seafloor larger than the city of San Francisco, but it could find no outer boundary to Dumpsite 2. Initial sonar surveys suggest there still could be thousands of physical barrels underwater filled with who knows what.

https://pubs.acs.org/doi/pdf/10.1021/acs.est.8b05859

As for the mystery of the DDT barrels, regulators combed old aerial photos of the Montrose Chemical Corp. plant near Torrance and the berth from which the waste haulers set sail. They called on every possible government agency to dig up its records and considered all the logistics that would have gone into transporting half a million physical barrels at the time.

Finally, they called up a retired EPA investigator who had been in charge of looking into the deep-sea DDT dumping. He explained that in the 1940s and '50s, local government agencies had asked waste haulers to report their quantities of waste with a default unit of measurement: barrels.

The exact volume remains unclear, but the standard at the time ranged from 42 to 55 gallons per barrel depending on the industry. It's also likely that there were rounding errors when the companies converted their massive tanks of waste into barrels, and that more chemicals were dumped than logged.

Regardless of how the waste got dumped into the ocean, sediment samples so far show that a lot of DDT is clearly down there. The big question now is whether the chemicals have been sequestered or embedded into the seafloor well enough to prevent them from remobilizing—or whether they have been recirculating in a way that threatens human health and California's marine environment.

... David Valentine, the University of California, Santa Barbara scientist whose research team first came across dozens of mysterious barrels underwater, said that not having a physical object to search for makes the issue more complicated—and even more concerning. If highly acidic DDT waste wasn't considered too bad to dump straight into the ocean, he wondered, what could've been worse that had to be put into an actual barrel?

"Maybe some of those barrels were the bad batches … but we don't really know. It could be a whole lot of other stuff too," said Valentine, who has been thinking through the next steps for research—in the field and in the lab.

Considering the latest information from the EPA, they described the material that got poured into the ocean as likely a hail or mist of DDT-laden particles raining down from the ocean surface.

"It's been sitting now on the seafloor, potentially for 60, 70 years," Valentine said. "What's happened to all this material during that time? Has it moved around? Is it working its way back into the ecosystem? Those are the things that we really need to start answering."

Scientist: Extent of DDT dumping in Pacific is 'staggering'
https://phys.org/news/2021-04-scientists-barrels-ddt-dump-site.html
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oren

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Re: Persistent chemical pollution
« Reply #4 on: August 09, 2022, 08:19:35 PM »
Even considering the general habits of our civilization, this is shocking.

kassy

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Re: Persistent chemical pollution
« Reply #5 on: August 11, 2022, 08:50:28 AM »
A Common 'Forever Chemical' Has Just Been Linked to Liver Cancer in Humans


A common 'forever chemical' known as PFOS (perfluorooctanesulfonic acid) has been linked to liver cancer in humans in a worrying new study.

Once a key ingredient in the water-repelling product commercially known as Scotchguard, PFOS was finally phased out soon after the turn of the century following concerns over its toxicity and environmental impact.

Still, it didn't earn its label of 'forever chemical' for nothing, with environmental levels of this and closely related substances remaining alarmingly high around the globe.

Now a study by researchers from the University of Southern California and the Icahn School of Medicine at Mount Sinai in the US have confirmed an association between PFOS and the development of a particularly deadly form of liver cancer.

Hepatocellular carcinoma (HCC) accounts for more than four out of five cases of liver cancer in the world. With a five-year survival rate of less than 20 percent, it's also regarded as one of the most deadly of cancers any of us could get.

....

With more than 98 percent of the adult US population having detectable concentrations of these compounds in their blood, researchers are now turning their attention to questions of what might be considered a 'safe' level of contamination.

Animal studies have demonstrated clear links between PFAS and liver damage. But what was really needed was a population-scale analysis of exposure and risk of ill health.

"Part of the reason there has been few human studies is because you need the right samples," says Veronica Wendy Setiawan, a cancer epidemiologist from the Keck School of Medicine at the University of Southern California.

"When you are looking at an environmental exposure, you need samples from well before a diagnosis because it takes time for cancer to develop."

As part of a collaboration with the University of Hawai'i called the Multiethnic Cohort Study, the researchers analyzed blood taken from 50 individuals a diagnosis of non-viral HCC.

These were compared with a carefully matched sample of bloods taken from 50 volunteers without a diagnosis.

Measuring levels of various types of PFAS in blood samples taken prior to the development of liver cancer, the researchers identified a strong association between PFOS and HCC.

Those in the top 10 percent of blood-PFOS levels, in fact, were 4.5 times more likely to develop HCC than those with lower blood-PFOS levels, providing the strongest evidence yet that we're capable of absorbing dangerous levels of these notorious substances.

"This study fills an important gap in our understanding of the true consequences of exposure to these chemicals," says the study's lead author, Keck School of Medicine public health researcher Leda Chatzi.

...

https://www.sciencealert.com/this-once-common-forever-chemical-has-just-been-linked-to-liver-cancer-in-humans
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vox_mundi

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Re: Persistent chemical pollution
« Reply #6 on: August 23, 2022, 02:26:25 PM »
Study First to Link Weed Killer Roundup to Convulsions In Animals
https://phys.org/news/2022-08-link-weed-killer-roundup-convulsions.html

A recent report by the United States Centers for Disease Control and Prevention found more than 80 percent of urine samples from children and adults in the U.S. contained the herbicide glyphosate. A study by Florida Atlantic University and Nova Southeastern University takes this research one step further and is the first to link the use of the herbicide Roundup, a widely used weed killer, to convulsions in animals.

https://www.cdc.gov/exposurereport/whats_new_071922_1.html

... Glyphosate-resistant crops account for almost 80 percent of transgenic crop cultivated land, which has resulted in an estimated 6.1 billion kilos of glyphosate sprayed across the world from 2005 to 2014.

Results, published in [I[Scientific Reports[/I], showed that glyphosate and Roundup increased seizure-like behavior in soil-dwelling roundworms and provides significant evidence that glyphosate targets GABA-A receptors. These communication points are essential for locomotion and are heavily involved in regulating sleep and mood in humans. What truly sets this research apart is that it was done at significantly less levels than recommended by the EPA and those used in past studies

"The concentration listed for best results on the Roundup Super Concentrate label is 0.98 percent glyphosate, which is about 5 tablespoons of Roundup in 1 gallon of water," said Naraine. "A significant finding from our study reveals that just 0.002 percent glyphosate, a difference of about 300 times less herbicide than the lowest concentration recommended for consumer use, had concerning effects on the nervous system."

The study found that the active ingredient glyphosate exacerbated convulsions in C. elegans and suggest the GABA-A receptor as a neurological target for the observed physiological changes. The data also indicate that there is an important distinction between exposure to glyphosate and Roundup (w/surfactants), with Roundup exposure increasing the percentage of C. elegans that did not recover from seizure activity. The non-recovery phenotype and prolonged convulsions in C. elegans from this study have helped to set a foundation for understanding nuanced physiological effects of herbicide that occur at concentrations exponentially below neurotoxic levels.

This study provides evidence to further investigate how chronic exposure and accumulation may lead to neurodegenerative diseases such as Parkinson's disease. Importantly, there also is a sub-neurodegenerative threshold that may dramatically impact dysregulation of neurotransmission.

Roundup and glyphosate's impact on GABA to elicit extended proconvulsant behavior in 12 Caenorhabditis elegans, Scientific Reports (2022).
https://www.nature.com/articles/s41598-022-17537-w
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kassy

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Re: Persistent chemical pollution
« Reply #7 on: August 25, 2022, 04:38:22 PM »
Toxic 'forever chemicals' accumulate above the water table

PFAS (per- and polyfluoroalkyl substances) are water-, stain-, and heat-resistant chemicals added to products like nonstick pans, nail polish, food wrappers, and firefighting foam. They have been linked to health problems, including thyroid disease, liver damage, and kidney cancer. Increasingly, PFAS have become a public health concern because they don't break down, instead accumulating in the environment. These so-called "forever chemicals" are now found virtually everywhere, from human blood to the top of Mount Everest. Researchers are urgently trying to understand how PFAS move through the environment to get a better grasp of the extent of the problem and how to control it.

n a new article published in Reviews of Geophysics, Xueyan Lyu and colleagues summarize research published between 2010 and 2022 regarding the fate and transport of PFAS in the soil, ground, and groundwater. The article reviews the physical and chemical properties of PFAS that affect how they move through the subsurface environment and what causes them to stick around. The authors pay particularly close attention to transitional spaces, like soil to groundwater and air to groundwater.

Strikingly, the authors found that just a handful of PFAS have been studied in any detail, even though more than 3,000 have been manufactured and the list continues to grow rapidly. They identified the portion of soil above the water table as a hot spot of PFAS accumulation. Of the PFAS studied, the ones with short carbon chains and negative charges were most likely to move through soil and contaminate the groundwater.

The authors emphasize, however, that most observational and modeling studies on the fate and transport of PFAS have been conducted at a fairly small scale in a laboratory setting. The authors call for large-scale studies in natural settings that will provide critical information necessary to assess the environmental and health impacts associated with the exposure to PFAS, along with future remediation endeavors.

https://phys.org/news/2022-08-toxic-chemicals-accumulate-table.html

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021RG000765
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vox_mundi

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Re: Persistent chemical pollution
« Reply #8 on: August 26, 2022, 04:35:15 PM »
EPA to Designate 'Forever Chemicals' as Hazardous Substances
https://phys.org/news/2022-08-epa-chemicals-hazardous-substances.html

The Environmental Protection Agency is designating some toxic industrial compounds used in cookware, carpets and firefighting foams as hazardous substances under the so-called Superfund law.

The designation means that releases of long-lasting chemicals known as PFOA and PFOS that meet or exceed a certain quantity would have to be reported to federal, state or tribal officials. The requirement would increase understanding of the extent and locations of the contamination and help communities avoid or reduce contact with the potentially dangerous chemicals, the EPA said.

PFOA and PFOS have been voluntarily phased out by U.S. manufacturers but are still in limited use and remain in the environment because they do not degrade over time. The compounds are part of a larger cluster of "forever chemicals" known as PFAS that have been used in consumer products and industry since the 1940s.

The chemicals can accumulate and persist in the human body for long periods of time, and evidence from animal and human studies indicates that exposure to PFOA or PFOS may lead to cancer or other health problems.

... The EPA's action follows a recent report by the National Academies of Science that calls PFAS a serious public health threat in the U.S. and worldwide.

The move follows an EPA announcement in June that PFOA and PFOS are more dangerous than previously thought and pose health risks even at levels so low they cannot currently be detected. ...

https://phys.org/news/2022-06-epa-chemicals-pose.html
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kassy

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Re: Persistent chemical pollution
« Reply #9 on: September 06, 2022, 10:49:47 AM »
Simple method destroys dangerous 'forever chemicals,' making water safe

If you're despairing at recent reports that Earth's water sources have been thoroughly infested with hazardous human-made chemicals called PFAS that can last for thousands of years, making even rainwater unsafe to drink, there's a spot of good news.

Chemists at UCLA and Northwestern University have developed a simple way to break down almost a dozen types of these nearly indestructible "forever chemicals" at relatively low temperatures with no harmful byproducts.

In a paper published today in the journal Science, the researchers show that in water heated to just 176 to 248 degrees Fahrenheit, common, inexpensive solvents and reagents severed molecular bonds in PFAS that are among the strongest known and initiated a chemical reaction that "gradually nibbled away at the molecule" until it was gone, said UCLA distinguished research professor and co-corresponding author Kendall Houk.

The simple technology, the comparatively low temperatures and the lack of harmful byproducts mean there is no limit to how much water can be processed at once, Houk added. The technology could eventually make it easier for water treatment plants to remove PFAS from drinking water.

Per- and polyfluoroalkyl substances -- PFAS for short -- are a class of around 12,000 synthetic chemicals that have been used since the 1940s in nonstick cookware, waterproof makeup, shampoos, electronics, food packaging and countless other products. They contain a bond between carbon and fluorine atoms that nothing in nature can break.

When these chemicals leach into the environment through manufacturing or everyday product use, they become part of the Earth's water cycle. Over the past 70 years, PFAS have contaminated virtually every drop of water on the planet, and their strong carbon-fluorine bond allows them to pass through most water treatment systems completely unharmed. They can accumulate in the tissues of people and animals over time and cause harm in ways that scientists are just beginning to understand. Certain cancers and thyroid diseases, for example, are associated with PFAS.

For these reasons, finding ways to remove PFAS from water has become particularly urgent. Scientists are experimenting with many remediation technologies, but most of them require extremely high temperatures, special chemicals or ultraviolet light and sometimes produce byproducts that are also harmful and require additional steps to remove.

Leading PFAS to the guillotine

Northwestern chemistry professor William Dichtel and doctoral student Brittany Trang noticed that while PFAS molecules contain a long "tail" of stubborn carbon-fluorine bonds, their "head" group often contains charged oxygen atoms, which react strongly with other molecules. Dichtel's team built a chemical guillotine by heating the PFAS in water with dimethyl sulfoxide, also known as DMSO, and sodium hydroxide, or lye, which lopped off the head and left behind an exposed, reactive tail.

"That triggered all these reactions, and it started spitting out fluorine atoms from these compounds to form fluoride, which is the safest form of fluorine," Dichtel said. "Although carbon-fluorine bonds are super-strong, that charged head group is the Achilles' heel."

But the experiments revealed another surprise: The molecules didn't seem to be falling apart the way conventional wisdom said they should.

To solve this mystery, Dichtel and Trang shared their data with collaborators Houk and Tianjin University student Yuli Li, who was working in Houk's group remotely from China during the pandemic. The researchers had expected the PFAS molecules would disintegrate one carbon atom at a time, but Li and Houk ran computer simulations that showed two or three carbon molecules peeled off the molecules simultaneously, just as Dichtel and Tang had observed experimentally.

The simulations also showed the only byproducts should be fluoride -- often added to drinking water to prevent tooth decay -- carbon dioxide and formic acid, which is not harmful. Dichtel and Trang confirmed these predicted byproducts in further experiments.

"This proved to be a very complex set of calculations that challenged the most modern quantum mechanical methods and fastest computers available to us," Houk said. "Quantum mechanics is the mathematical method that simulates all of chemistry, but only in the last decade have we been able to take on large mechanistic problems like this, evaluating all the possibilities and determining which one can happen at the observed rate."

Li, Houk said, has mastered these computational methods, and he worked long distance with Trang to solve the fundamental but practically significant problem.

The current work degraded 10 types of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl ether carboxylic acids (PFECAs), including perfluorooctanoic acid (PFOA). The researchers believe their method will work for most PFAS that contain carboxylic acids and hope it will help identify weak spots in other classes of PFAS. They hope these encouraging results will lead to further research that tests methods for eradicating the thousands of other types of PFAS.

The study, "Low-temperature mineralization of perfluorocarboxylic acids," was supported by the National Science Foundation.

https://www.sciencedaily.com/releases/2022/08/220818163721.htm

Nice find.
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SteveMDFP

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Re: Persistent chemical pollution
« Reply #10 on: September 06, 2022, 02:16:57 PM »
...
In a paper published today in the journal Science, the researchers show that in water heated to just 176 to 248 degrees Fahrenheit, common, inexpensive solvents and reagents severed molecular bonds in PFAS that are among the strongest known and initiated a chemical reaction that "gradually nibbled away at the molecule" until it was gone, said UCLA distinguished research professor and co-corresponding author Kendall Houk.
...

Northwestern chemistry professor William Dichtel and doctoral student Brittany Trang noticed that while PFAS molecules contain a long "tail" of stubborn carbon-fluorine bonds, their "head" group often contains charged oxygen atoms, which react strongly with other molecules. Dichtel's team built a chemical guillotine by heating the PFAS in water with dimethyl sulfoxide, also known as DMSO, and sodium hydroxide, or lye, which lopped off the head and left behind an exposed, reactive tail.

The simulations also showed the only byproducts should be fluoride -- often added to drinking water to prevent tooth decay -- carbon dioxide and formic acid, which is not harmful. Dichtel and Trang confirmed these predicted byproducts in further experiments.
...
The study, "Low-temperature mineralization of perfluorocarboxylic acids," was supported by the National Science Foundation.

https://www.sciencedaily.com/releases/2022/08/220818163721.htm

Nice find.

Nice find, indeed.  Considering the rate of flow of water in a typical municipal water supply, I'm skeptical that this heat and chemical treatment could be accomplished at an economically feasible rate.  Still, quantities treated for just drinking and cooking should be feasible for advanced economies.  Poor countries?  Likely out of reach.

kassy

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Re: Persistent chemical pollution
« Reply #11 on: September 16, 2022, 05:45:13 PM »
This story is not new. See reply #6 above which also links to the paper. Please just check at least the current page.

Bonus link to upgrade this post.
Update on human exposure to glyphosate, with a complete review of exposure in children
https://ehjournal.biomedcentral.com/articles/10.1186/s12940-020-00673-z

A recent meta-analysis has suggested that glyphosate use in an occupational setting may raise the risk of non-Hodgkin lymphoma as much as 41% [4]; a pooled analysis of case-control studies from North America confirmed the association, and suggested that specific histologic subtypes of non-Hodgkin lymphoma may be associated with exposure to glyphosate
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kassy

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Re: Persistent chemical pollution
« Reply #12 on: September 21, 2022, 06:31:36 PM »
School uniforms in N America linked to PFAS "forever chemicals"

A study of school uniforms in the US and Canada reveals high levels of so-called "forever chemicals".

The chemicals, known as PFAS, are used to make clothing resistant to stains or water but they have been linked to asthma, obesity and fertility issues.

Researchers found that uniforms made with 100% cotton showed higher levels than synthetic materials.

Exposing children to these chemicals may increase the long-term health risk, the scientists believe.

The issue is less of a concern in the UK because almost all retailers' own brand uniforms are PFAS free, say campaigners.

...

https://www.bbc.com/news/science-environment-62982397

On the upside they are easy to wash...
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