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From Dream to Reality: Low-Cost, Carbon-Neutral Biofuels Are Finally Possible

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Monday, March 18, 2024

UCR’s Charles Cai and a newly installed 20-gallon CELF reactor that will be used in the scale-up project. Credit: Stan Lim / UCRIn the process of converting plants into fuel, the initial phase — decomposing the plant material — has consistently posed the greatest challenge. Recent research reveals that incorporating an easily renewable chemical during the pretreatment phase could, at last, render the production of advanced biofuels economically viable and carbon neutral.For biofuels to compete with petroleum, biorefinery operations must be designed to better utilize lignin. Lignin is one of the main components of plant cell walls. It provides plants with greater structural integrity and resiliency from microbial attacks. However, these natural properties of lignin also make it difficult to extract and utilize from the plant matter, also known as biomass.“Lignin utilization is the gateway to making what you want out of biomass in the most economical and environmentally friendly way possible,” said UC Riverside Associate Research Professor Charles Cai. “Designing a process that can better utilize both the lignin and sugars found in biomass is one of the most exciting technical challenges in this field.” To overcome the lignin hurdle, Cai invented CELF, which stands for co-solvent enhanced lignocellulosic fractionation. It is an innovative biomass pretreatment technology.“CELF uses tetrahydrofuran or THF to supplement water and dilute acid during biomass pretreatment. It improves overall efficiency and adds lignin extraction capabilities,” Cai said. “Best of all, THF itself can be made from biomass sugars.”Economic and Environmental Advantages of CELFA landmark Energy & Environmental Science paper details the degree to which a CELF biorefinery offers economic and environmental benefits over both petroleum-based fuels and earlier biofuel production methods.The paper is a collaboration between Cai’s research team at UCR, the Center for Bioenergy Innovation managed by Oak Ridge National Laboratories, and the National Renewable Energy Laboratory, with funding provided by the U.S. Department of Energy’s Office of Science. In it, the researchers consider two main variables: what kind of biomass is most ideal and what to do with the lignin once it’s been extracted.UC Riverside Associate Research Professor Charles Cai, who invented CELF, a biomass pretreatment technology that could make next-generation biofuels competitive with petroleum. Credit: Stan Lim / UCRFirst-generation biofuel operations use food crops like corn, soy, and sugarcane as raw materials, or feedstocks. Because these feedstocks divert land and water away from food production, using them for biofuels is not ideal.Second-generation operations use non-edible plant biomass as feedstocks. An example of biomass feedstocks includes wood residues from milling operations, sugarcane bagasse, or corn stover, all of which are abundant low-cost byproducts of forestry and agricultural operations.According to the Department of Energy, up to a billion tons per year of biomass could be made available for the manufacture of biofuels and bioproducts in the US alone, capable of displacing 30% of our petroleum consumption while also creating new domestic jobs.Selecting Optimal Feedstocks and Achieving Economic BenefitsBecause a CELF biorefinery can more fully utilize plant matter than earlier second-generation methods, the researchers found that a heavier, denser feedstock like hardwood poplar is preferable over less carbon-dense corn stover for yielding greater economic and environmental benefits.Using poplar in a CELF biorefinery, the researchers demonstrate that sustainable aviation fuel could be made at a break-even price as low as $3.15 per gallon of gasoline-equivalent. The current average cost for a gallon of jet fuel in the U.S. is $5.96.The U.S. government issues credits for biofuel production in the form of renewable identification number credits, a subsidy meant to bolster domestic biofuel production. The tier of these credits issued for second-generation biofuels, the D3 tier, is typically traded at $1 per gallon or higher. At this price per credit, the paper demonstrates that one can expect a rate of return of over 20% from the operation.“Spending a little more for a more carbon-rich feedstock like poplar still yields more economic benefits than a cheaper feedstock like corn stover, because you can make more fuel and chemicals from it,” Cai said.The paper also illustrates how lignin utilization can positively contribute to overall biorefinery economics while keeping the carbon footprint as low as possible. In older biorefinery models, where biomass is cooked in water and acid, the lignin is mostly unusable for more than its heating value.“The older models would elect to burn the lignin to supplement heat and energy for these biorefineries because they could mostly only leverage the sugars in the biomass – a costly proposition that leaves a lot of value off the table,” said Cai.In addition to better lignin utilization, the CELF biorefinery model also proposes to produce renewable chemicals. These chemicals could be used as building blocks for bioplastics and food and drink flavoring compounds. These chemicals take up some of the carbon in the plant biomass that would not get released back into the atmosphere as CO2.“Adding THF helps reduce the energy cost of pretreatment and helps isolate lignin, so you wouldn’t have to burn it anymore. On top of that, we can make renewable chemicals that help us achieve a near-zero global warming potential,” Cai said. “I think this moves the needle from Gen 2 biofuels to Gen 2+.”In light of the team’s recent successes, the Department of Energy’s Bioenergy Technology Office has awarded the researchers a $2 million grant to build a small-scale CELF pilot plant at UCR. Cai hopes that demonstrating the pilot plant will lead to larger-scale investment in the technology, as harnessing energy from fossil fuels adds to global warming and hurts the planet.“I began this work more than a decade ago because I wanted to make an impact. I wanted to find a viable alternative to fossil fuels and my colleagues and I have done that,” Cai said. “Using CELF, we have shown it is possible to create cost-effective fuels from biomass and lignin and help curb our contribution of carbon emissions into the atmosphere.”Reference: “Economics and global warming potential of a commercial-scale delignifying biorefinery based on co-solvent enhanced lignocellulosic fractionation to produce alcohols, sustainable aviation fuels, and co-products from biomass” by Bruno Colling Klein, Brent Scheidemantle, Rebecca J. Hanes, Andrew W. Bartling, Nicholas J. Grundl, Robin J. Clark, Mary J. Biddy, Ling Tao, Cong T. Trinh, Adam M. Guss, Charles E. Wyman, Arthur J. Ragauskas, Erin G. Webb, Brian H. Davison and Charles M. Cai, 13 December 2023, Energy & Environmental Science.DOI: 10.1039/D3EE02532B

In the process of converting plants into fuel, the initial phase — decomposing the plant material — has consistently posed the greatest challenge. Recent research...

Charles Cai and Celf Reactor

UCR’s Charles Cai and a newly installed 20-gallon CELF reactor that will be used in the scale-up project. Credit: Stan Lim / UCR

In the process of converting plants into fuel, the initial phase — decomposing the plant material — has consistently posed the greatest challenge. Recent research reveals that incorporating an easily renewable chemical during the pretreatment phase could, at last, render the production of advanced biofuels economically viable and carbon neutral.

For biofuels to compete with petroleum, biorefinery operations must be designed to better utilize lignin. Lignin is one of the main components of plant cell walls. It provides plants with greater structural integrity and resiliency from microbial attacks. However, these natural properties of lignin also make it difficult to extract and utilize from the plant matter, also known as biomass.

“Lignin utilization is the gateway to making what you want out of biomass in the most economical and environmentally friendly way possible,” said UC Riverside Associate Research Professor Charles Cai. “Designing a process that can better utilize both the lignin and sugars found in biomass is one of the most exciting technical challenges in this field.”

To overcome the lignin hurdle, Cai invented CELF, which stands for co-solvent enhanced lignocellulosic fractionation. It is an innovative biomass pretreatment technology.

“CELF uses tetrahydrofuran or THF to supplement water and dilute acid during biomass pretreatment. It improves overall efficiency and adds lignin extraction capabilities,” Cai said. “Best of all, THF itself can be made from biomass sugars.”

Economic and Environmental Advantages of CELF

A landmark Energy & Environmental Science paper details the degree to which a CELF biorefinery offers economic and environmental benefits over both petroleum-based fuels and earlier biofuel production methods.

The paper is a collaboration between Cai’s research team at UCR, the Center for Bioenergy Innovation managed by Oak Ridge National Laboratories, and the National Renewable Energy Laboratory, with funding provided by the U.S. Department of Energy’s Office of Science. In it, the researchers consider two main variables: what kind of biomass is most ideal and what to do with the lignin once it’s been extracted.

Charles Cai

UC Riverside Associate Research Professor Charles Cai, who invented CELF, a biomass pretreatment technology that could make next-generation biofuels competitive with petroleum. Credit: Stan Lim / UCR

First-generation biofuel operations use food crops like corn, soy, and sugarcane as raw materials, or feedstocks. Because these feedstocks divert land and water away from food production, using them for biofuels is not ideal.

Second-generation operations use non-edible plant biomass as feedstocks. An example of biomass feedstocks includes wood residues from milling operations, sugarcane bagasse, or corn stover, all of which are abundant low-cost byproducts of forestry and agricultural operations.

According to the Department of Energy, up to a billion tons per year of biomass could be made available for the manufacture of biofuels and bioproducts in the US alone, capable of displacing 30% of our petroleum consumption while also creating new domestic jobs.

Selecting Optimal Feedstocks and Achieving Economic Benefits

Because a CELF biorefinery can more fully utilize plant matter than earlier second-generation methods, the researchers found that a heavier, denser feedstock like hardwood poplar is preferable over less carbon-dense corn stover for yielding greater economic and environmental benefits.

Using poplar in a CELF biorefinery, the researchers demonstrate that sustainable aviation fuel could be made at a break-even price as low as $3.15 per gallon of gasoline-equivalent. The current average cost for a gallon of jet fuel in the U.S. is $5.96.

The U.S. government issues credits for biofuel production in the form of renewable identification number credits, a subsidy meant to bolster domestic biofuel production. The tier of these credits issued for second-generation biofuels, the D3 tier, is typically traded at $1 per gallon or higher. At this price per credit, the paper demonstrates that one can expect a rate of return of over 20% from the operation.

“Spending a little more for a more carbon-rich feedstock like poplar still yields more economic benefits than a cheaper feedstock like corn stover, because you can make more fuel and chemicals from it,” Cai said.

The paper also illustrates how lignin utilization can positively contribute to overall biorefinery economics while keeping the carbon footprint as low as possible. In older biorefinery models, where biomass is cooked in water and acid, the lignin is mostly unusable for more than its heating value.

“The older models would elect to burn the lignin to supplement heat and energy for these biorefineries because they could mostly only leverage the sugars in the biomass – a costly proposition that leaves a lot of value off the table,” said Cai.

In addition to better lignin utilization, the CELF biorefinery model also proposes to produce renewable chemicals. These chemicals could be used as building blocks for bioplastics and food and drink flavoring compounds. These chemicals take up some of the carbon in the plant biomass that would not get released back into the atmosphere as CO2.

“Adding THF helps reduce the energy cost of pretreatment and helps isolate lignin, so you wouldn’t have to burn it anymore. On top of that, we can make renewable chemicals that help us achieve a near-zero global warming potential,” Cai said. “I think this moves the needle from Gen 2 biofuels to Gen 2+.”

In light of the team’s recent successes, the Department of Energy’s Bioenergy Technology Office has awarded the researchers a $2 million grant to build a small-scale CELF pilot plant at UCR. Cai hopes that demonstrating the pilot plant will lead to larger-scale investment in the technology, as harnessing energy from fossil fuels adds to global warming and hurts the planet.

“I began this work more than a decade ago because I wanted to make an impact. I wanted to find a viable alternative to fossil fuels and my colleagues and I have done that,” Cai said. “Using CELF, we have shown it is possible to create cost-effective fuels from biomass and lignin and help curb our contribution of carbon emissions into the atmosphere.”

Reference: “Economics and global warming potential of a commercial-scale delignifying biorefinery based on co-solvent enhanced lignocellulosic fractionation to produce alcohols, sustainable aviation fuels, and co-products from biomass” by Bruno Colling Klein, Brent Scheidemantle, Rebecca J. Hanes, Andrew W. Bartling, Nicholas J. Grundl, Robin J. Clark, Mary J. Biddy, Ling Tao, Cong T. Trinh, Adam M. Guss, Charles E. Wyman, Arthur J. Ragauskas, Erin G. Webb, Brian H. Davison and Charles M. Cai, 13 December 2023, Energy & Environmental Science.
DOI: 10.1039/D3EE02532B

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Personal care product use during pregnancy, lactation may increase exposure to ‘forever chemicals’: Study

The use of certain personal care products during pregnancy or lactation may be linked to increased levels of "forever chemicals" in both blood plasma and breast milk, a new study has found. While past research has confirmed the presence of these toxic compounds in such items, the study authors sought to determine whether the use...

The use of certain personal care products during pregnancy or lactation may be linked to increased levels of "forever chemicals" in both blood plasma and breast milk, a new study has found. While past research has confirmed the presence of these toxic compounds in such items, the study authors sought to determine whether the use of nail polish, makeup and hair dyes alters the concentrations of the compounds in the body during and after pregnancy. Exploring this question in the maternal context was important because prenatal exposure to the chemicals — per- and polyfluoroalkyl substances (PFAS) — has been connected to adverse birth outcomes, according to the researchers, who published their findings in Environment International. Some such effects include reduced birth weight, preterm birth, certain neurodevelopmental disorders and diminished vaccine uptake in children, according to the multi-national research team. Known for their ability to persist in the body and the environment, PFAS are already linked to a variety of serious health conditions, including thyroid disease, kidney cancer and testicular cancer. There are thousands of types of PFAS, many of which are known for their nonstick and water-resistant properties — making them frequent ingredients in cosmetics and numerous household products. To evaluate the personal care product and pregnancy question, the researchers analyzed data from the Maternal-Infant Research on Environmental Chemicals Study, which included 2,001 pregnant people from 10 Canadian cities, between 2008 and 2011. The scientists considered the contributions of personal care products to PFAS concentrations in both prenatal blood plasma, from six to 13 gestational weeks, and human milk, from two to 10 weeks postpartum. They also received reports from participants about the frequency of product use across eight categories during the first and third trimesters, one to two days postpartum and two to 10 weeks postpartum. Participants who wore makeup daily in the first and third trimesters had 14 percent and 17 percent higher PFAS concentrations in their blood and breast milk, respectively, compared to those who did not, according to the study. People who used colored-permanent dye one to two days postpartum had 16 to 18 percent higher levels of PFAS in their milk than those who did not use dyes, the researchers found. Because the study only evaluated four types of PFAS commonly used in industry and commerce, the authors stressed their belief that their results were an underestimation of exposure levels. Despite the alarming nature of their results, the scientists stressed that on the plus side, such scientific evidence can help inform future regulation and guide individual choices.  “While PFAS are ubiquitous in the environment, our study indicates that personal care products are a modifiable source of PFAS,” lead author Amber Hall, a postdoctoral research associate in epidemiology at the Brown University School of Public Health, said in a statement. “People who are concerned about their level of exposure to these chemicals during pregnancy or while breastfeeding may benefit from cutting back on personal care products during those times,” Hall added.

Admir Masic: Using lessons from the past to build a better future

The associate professor of civil and environmental engineering studies ancient materials while working to solve modern problems.

As a teenager living in a small village in what was then Yugoslavia, Admir Masic witnessed the collapse of his home country and the outbreak of the Bosnian war. When his childhood home was destroyed by a tank, his family was forced to flee the violence, leaving their remaining possessions to enter a refugee camp in northern Croatia.It was in Croatia that Masic found what he calls his “magic.”“Chemistry really forcefully entered my life,” recalls Masic, who is now an associate professor in MIT’s Department of Civil and Environmental Engineering. “I’d leave school to go back to my refugee camp, and you could either play ping-pong or do chemistry homework, so I did a lot of homework, and I began to focus on the subject.”Masic has never let go of his magic. Long after chemistry led him out of Croatia, he’s come to understand that the past holds crucial lessons for building a better future. That’s why he started the MIT Refugee Action Hub (now MIT Emerging Talent) to provide educational opportunities to students displaced by war. It’s also what led him to study ancient materials, whose secrets he believes have potential to solve some of the modern world’s most pressing problems.“We’re leading this concept of paleo-inspired design: that there are some ideas behind these ancient materials that are useful today,” Masic says. “We should think of these materials as a source of valuable information that we can try to translate to today. These concepts have the potential to revolutionize how we think about these materials.”One key research focus for Masic is cement. His lab is working on ways to transform the ubiquitous material into a carbon sink, a medium for energy storage, and more. Part of that work involves studying ancient Roman concrete, whose self-healing properties he has helped to illuminate.At the core of each of Masic’s research endeavors is a desire to translate a better understanding of materials into improvements in how we make things around the world.“Roman concrete to me is fascinating: It’s still standing after all this time and constantly repairing,” Masic says. “It’s clear there’s something special about this material, so what is it? Can we translate part of it into modern analogues? That’s what I love about MIT. We are put in a position to do cutting-edge research and then quickly translate that research into the real world. Impact for me is everything.”Finding a purposeMasic’s family fled to Croatia in 1992, just as he was set to begin high school. Despite excellent grades, Masic was told Bosnian refugees couldn't enroll in the local school. It was only after a school psychologist advocated for Masic that he was allowed to sit in on classes as a nonmatriculating student.Masic did his best to be a ghost in the back of classrooms, silently absorbing everything he could. But in one subject he stood out. Within six months of joining the school, in January of 1993, a teacher suggested Masic compete in a local chemistry competition.“It was kind of the Olympiads of chemistry, and I won,” Masic recalls. “I literally floated onto the stage. It was this ‘Aha’ moment. I thought, ‘Oh my god, I’m good at chemistry!’”In 1994, Masic’s parents immigrated to Germany in search of a better life, but he decided to stay behind to finish high school, moving into a friend’s basement and receiving food and support from local families as well as a group of volunteers from Italy.“I just knew I had to stay,” Masic says. “With all the highs and lows of life to that point, I knew I had this talent and I had to make the most of it. I realized early on that knowledge was the one thing no one could take away from me.”Masic continued competing in chemistry competitions — and continued winning. Eventually, after a change to a national law, the high school he was attending agreed to give him a diploma. With the help of the Italian volunteers, he moved to Italy to attend the University of Turin, where he entered a five-year joint program that earned him a master’s degree in inorganic chemistry. Masic stayed at the university for his PhD, where he studied parchment, a writing material that’s been used for centuries to record some of humanity’s most sacred texts.With a classmate, Masic started a company that helped restore ancient documents. The work took him to Germany to work on a project studying the Dead Sea Scrolls, a set of manuscripts that date as far back as the third century BCE. In 2008, Masic joined the Max Planck Institute in Germany, where he also began to work with biological materials, studying water’s interaction with collagen at the nanoscale.Through that work, Masic became an expert in Raman spectroscopy, a type of chemical imaging that uses lasers to record the vibrations of molecules without leaving a trace, which he still uses to characterize materials.“Raman became a tool for me to contribute in the field of biological materials and bioinspired materials,” Masic says. “At the same time, I became the ‘Raman guy.’ It was a remarkable period for me professionally, as these tools provided unparalleled information and I published a lot of papers.”After seven years at Max Planck, Masic joined the Department of Civil and Environmental Engineering (CEE) at MIT.“At MIT, I felt I could truly be myself and define the research I wanted to do,” Masic says. “Especially in CEE, I could connect my work in heritage science and this tool, Raman spectroscopy, to tackle our society’s big challenges.”From labs to the worldRaman spectroscopy is a relatively new approach to studying cement, a material that contributes significantly to carbon dioxide emissions worldwide. At MIT, Masic has explored ways cement could be used to store carbon dioxide and act as an energy-storing supercapacitor. He has also solved ancient mysteries about the lasting strength of ancient Roman concrete, with lessons for the $400 billion cement industry today.“We really don’t think we should replace ordinary Portland cement completely, because it’s an extraordinary material that everyone knows how to work with, and industry produces so much of it. We need to introduce new functionalities into our concrete that will compensate for cement’s sustainability issues through avoided emissions,” Masic explains. “The concept we call ‘multifunctional concrete’ was inspired by our work with biological materials. Bones, for instance, sacrifice mechanical performance to be able to do things like self-healing and energy storage. That's how you should imagine construction over next 10 years or 20 years. There could be concrete columns and walls that primarily offer support but also do things like store energy and continuously repair themselves.”Masic's work across academia and industry allows him to apply his multifunctional concrete research at scale. He serves as a co-director of the MIT ec3 hub, a principal investigator within MIT Concrete Sustainability Hub, and a co-founder and advisor at the technology development company DMAT.“It’s great to be at the forefront of sustainability but also to be directly interacting with key industry players that can change the world,” Masic says. “What I appreciate about MIT is how you can engage in fundamental science and engineering while also translating that work into practical applications. The CSHub and ec3 hub are great examples of this. Industry is eager for us to develop solutions that they can help support.”And Masic will never forget where he came from. He now lives in Somerville, Massachusetts, with his wife Emina, a fellow former refugee, and their son, Benjamin, and the family shares a deep commitment to supporting displaced and underserved communities. Seven years ago, Masic founded the MIT Refugee Action Hub (ReACT), which provides computer and data science education programs for refugees and displaced communities. Today thousands of refugees apply to the program every year, and graduates have gone on to successful careers at places like Microsoft and Meta. The ReACT program was absorbed by MIT’s Emerging Talent program earlier this year to further its reach.“It’s really a life-changing experience for them,” Masic says. “It’s an amazing opportunity for MIT to nurture talented refugees around the world through this simple certification program. The more people we can involve, the more impact we will have on the lives of these truly underserved communities.”

Controversial Prop. 65 warning labels about toxic chemicals are effective, study says

A new study finds California's Proposition 65 law has reduced toxic chemical exposure nationwide, despite longstanding criticism over its effectiveness.

For nearly 40 years, a controversial California law has required companies to place warning labels on their products alerting consumers to the potential health threats posed by chemicals, or else face lawsuits from lawyers, private citizens and advocacy groups.Passed as a ballot initiative, the Safe Drinking Water and Toxic Enforcement Act of 1986 has resulted in warnings being affixed to everything from vinyl-covered Bibles to gas station pumps, advising that exposure to some 900 chemicals can cause cancer, birth defects or reproductive harm. Ever since the passage of Proposition 65, policymakers and business groups have argued over whether the law is effective in preventing people from ingesting and inhaling toxic chemicals, or just providing a payday to plaintiffs attorneys.Now, a new study published in Environmental Health Perspectives has concluded that Proposition 65 has curbed exposure to toxic substances in California — and nationally.“If you live in California, the warnings are everywhere,” said Kristin Knox, a senior researcher at the Silent Spring Institute, a nonprofit that investigates the links between breast cancer and chemicals found in consumer products and the environment. “They’re on all sorts of stuff. So it’s very easy for people to make fun of Prop. 65 because you’re like, there’s warnings on my coffee and in my parking garage. But, for us, that made it even more important to be able to go and see if it’s having effects.” The study, conducted by Silent Spring and UC Berkeley researchers, suggests the law helped to reduce exposure to toxic substances commonly found in diesel exhaust and plastic materials. In order to gauge the law’s effectiveness, study authors examined the prevalence of chemicals found in blood and urine samples collected by the Centers for Disease Control and Prevention.The researchers analyzed concentrations of 11 chemicals placed on the Proposition 65 warning list and monitored by the CDC between 1999 and 2016. They included several types of phthalates, chemicals used to make plastics flexible; chloroform, a toxic byproduct from disinfecting water with chlorine; and toluene, a hazardous substance found in vehicle exhaust. They found that the majority of samples had significantly lower concentrations of these chemicals after their listing. But the levels didn’t just decline in California, they fell nationwide. However, California residents had lower chemical levels compared to the rest of the U.S., possibly due to more stringent environmental regulations and consumer awareness, according to researchers.Study authors surmised that the concentrations fell, in part, because businesses removed the chemicals from their goods to avoid warning labels. “It sounds like they reformulate to avoid having to put a Prop. 65 label on their product,” Knox said. “But when they reformulate, they reformulate nationwide. It’s not like they’re going to make a product just for California. And so this state regulation is actually having a national impact.”But swapping one chemical for an unlisted substitute has sometimes resulted in its own consequences. For example, when bisphenol A, an ingredient in plastics, was listed in 2013, chemical concentrations in blood and urine samples subsequently fell by 15%. However, that was followed by a 20% rise in bisphenol S — a closely related chemical also linked with reproductive toxicity.“That’s not what we want to see, and that’s an argument for regulating chemicals as a class, rather than specific chemicals,” Knox said.Business leaders have long been skeptical of Proposition 65’s effectiveness. They argue that the extensive list of chemicals has led to nearly universal warnings, which they say has undermined the law’s original intent and given consumers warning fatigue. Since 2010, companies have settled more than $200 million in Proposition 65-related lawsuits, according to the California Chamber of Commerce. Proposition 65, they say, has resulted in a cottage industry of so-called bounty hunters that target California companies for payouts.“Prop. 65 is infamous for its ubiquitous warnings and its bounty hunters who have abused the law to shake down businesses,” Adam Regele, vice president of advocacy for CalChamber, said in a statement. “For many chemicals, it requires warnings at levels 1,000 times below the level known to cause no effect in animal studies. It therefore should come as no surprise that listing a chemical under Prop. 65 prompts businesses to avoid it — if they can. The more important question is whether these changes have any public health benefit, and particularly at what cost to consumers.”Experts say some of the legal action is warranted and paved the way for reform.Dr. Meg Schwarzman, a physician and environmental scientist at UC Berkeley, said Proposition 65 has encouraged regulation that has reduced air pollution. Diesel was recognized as a carcinogen and listed under Proposition 65 in 1990. Several lawsuits were lodged against businesses, including school bus manufacturers and a major grocery chain. Perhaps the most notable was filed by then California Atty. Gen. Kamala Harris, who sued tenants at the Port of Los Angeles and Port of Long Beach for failure to warn residents that diesel emissions can cause cancer. Not long after its Proposition 65 designation, the California Air Resources Board classified diesel exhaust as a toxic air contaminant, enabling the agency to regulate it. It later adopted a number of rules curtailing diesel pollution in heavy-duty trucks and equipment at ports.From 1990 to 2014, diesel emissions dropped by 78% in California, compared with 51% nationally.“Californians have lower body burdens of many known toxic chemicals than people living outside of here,” said Schwarzman. “And that shows that whatever combination of our environmental laws targeting toxics is having an effect.”

US air force backpedals claim it is not responsible for PFAS cleanup in Arizona

Air force had earlier claimed supreme court’s overturning of Chevron doctrine had exempted it from EPA’s orderThe US air force has backpedaled on a claim that the supreme court’s recent reversal of the Chevron doctrine shields it against regulators’ orders to clean drinking water the military polluted in Tucson, Arizona.The air force’s bases partially contaminated water supplies for more than 500,000 people with toxic PFAS “forever chemicals” and other dangerous compounds. In a July letter in which it refused to comply with the Environmental Protection Agency’s May orders to address the problem, air force attorneys cited the reversal of Chevron. It claimed “the EPA’s order can not withstand review”. Continue reading...

The US air force has backpedaled on a claim that the supreme court’s recent reversal of the Chevron doctrine shields it against regulators’ orders to clean drinking water the military polluted in Tucson, Arizona.The air force’s bases partially contaminated water supplies for more than 500,000 people with toxic PFAS “forever chemicals” and other dangerous compounds. In a July letter in which it refused to comply with the Environmental Protection Agency’s May orders to address the problem, air force attorneys cited the reversal of Chevron. It claimed “the EPA’s order can not withstand review”.However, in a 24 October letter, the air force changed its position, and agreed to partially fund treatment plants that will remove the extremely high levels of PFAS contaminating some of Tucson’s water supplies. The change of course follows an August Guardian story on the issue that generated outrage.Legal observers who reviewed the claim in August highly doubted it would hold up if the military attempted to act on it.The new plan agreed upon by the air force, city of Tucson and EPA was “excellent” and would address the PFAS pollution while stipulating that the air force pay its fair share, said David Uhlmann, an assistant administrator with the EPA’s enforcement division.“This plan provides a long-term solution to address PFAS pollution in the aquifer,” Uhlmann said, noting that it was especially important in the desert west where drinking water supplies are limited.The supreme court in late June overturned the 40-year-old Chevron doctrine, one of its most important precedents. The decision sharply cut regulators’ power by giving judges the final say in interpreting ambiguous areas of the law during rule-making. Judges previously gave deference to regulatory agency experts on such questions, and the reversal is expected to have a profound impact on the EPA’s ability to protect the public from pollution.A 10-sq-mile (26 sq km) area around the facilities and Tucson international airport were in the 1980s designated as a Superfund site, an action reserved for the nation’s most polluted areas.While several air force bases are responsible for trichloroethylene (TCE) – volatile organic compounds – and PFAS contamination, the municipal airport also used PFAS-laden firefighting foam on the site and is responsible for some of the pollution.Filtration systems put in place in 2014 for TCE and other chemicals are currently removing PFAS, but the systems were not designed to remove PFAS, and the added burden is straining the system. Officials previously shut down a well in 2021 when contaminated water nearly broke through the system, the EPA wrote. Such a breach could leave the entire Arizona city without safe water.The air force’s refusal to comply with the EPA order was viewed as an early indication of how polluters will wield the ruling to evade responsibility and underscored the stakes.Legal observers in August said the military was attempting to expand the scope of the Chevron ruling, and it could not be applied to EPA enforcement actions like the Tucson order – it only affects the rule-making process. Moreover, one arm of a presidential administration cannot sue another, so the military cannot sue the EPA.Uhlmann said he was not sure why the air force made the Chevron claim, but added he did not “think the statements made in the July letter were views shared by senior defense officials or air force leadership”.“The EPA and DoD take seriously the obligation of the US government to address PFAS contamination and other forms of pollution related to operation of DoD installations,” Uhlmann told the Guardian.Part of the dispute lay in the level of responsibility for the pollution, and the new agreement will continue an investigation into the percentage for which each party must pay.In the meantime, the air force has agreed to pay for 50% of past costs, which the city has so far covered. It will also pay 50% of the future capital costs for new plants, as well as operation and maintenance into perpetuity. If the ongoing investigation finds the air force is responsible for a level of the pollution above or below 50%, then the amount it pays will be adjusted.In its October letter to the EPA, the air force wrote it is making a “firm commitment” to the plan.

PFAS mixtures more toxic than single compounds, suggesting higher danger

First-of-its-kind research highlights need for change to regulation, as humans almost always exposed to mixtures Mixtures of different types of PFAS compounds are often more toxic than single chemicals, first-of-its-kind research finds, suggesting humans’ exposure to the chemicals is more dangerous than previously thought.Humans are almost always exposed to more than one PFAS compound at a time, but regulatory agencies largely look at the chemicals in isolation from one another, meaning regulators are probably underestimating the health threat. Continue reading...

Mixtures of different types of PFAS compounds are often more toxic than single chemicals, first-of-its-kind research finds, suggesting humans’ exposure to the chemicals is more dangerous than previously thought.Humans are almost always exposed to more than one PFAS compound at a time, but regulatory agencies largely look at the chemicals in isolation from one another, meaning regulators are probably underestimating the health threat.“Our point is that PFAS needs to be regulated as mixtures,” said Diana Aga, a study co-author with the University of Buffalo, which partnered with the Helmholtz Centre for Environmental Research in Germany.PFAS are a class of about 15,000 compounds most frequently used to make products water-, stain- and grease-resistant. They have been linked to cancer, birth defects, decreased immunity, high cholesterol, kidney disease and a range of other serious health problems. They are dubbed “forever chemicals” because they do not naturally break down in the environment.The study, which relied on modeling with in vitro cells, not human or animal studies, checked the neurotoxicity and cytotoxicity for combinations of up to 12 PFAS compounds that the federal government has regularly found in water. It also looked at a combination of four PFAS that the US Centers for Disease Control and Prevention has often found in blood serum.Cytotoxicity refers to toxicity to cells, and the researchers measured oxidative stress, which is a marker of potential health impacts.The research did not find a synergistic effect in which a combination of PFAS enhanced the chemicals’ toxicity – instead, it showed that the toxicity is additive.Aga likened it to finding that “one plus one equals two”, rather than “one plus one equals 10”, as some had feared might be the case with PFAS compounds.“Originally, that’s what we thought, but it’s not synergistic. It’s just simple addition,” Aga said.Still, it is a problem in the real world because some compounds are more toxic than others. PFOA and PFOS are two of the most common and dangerous PFAS chemicals, research over recent decades has found, and one of those compounds is very frequently found in contaminated human blood or drinking water.The sum of those chemicals can present a danger, even if they are below the Environmental Protection Agency’s drinking-water limits of 4ppt (parts per trillion) for each.Hypothetically, if PFOA and PFOS levels were present at 3ppt each, then the water would be considered safe by EPA standards. But the sum of each chemical’s toxicity would probably make the water dangerously toxic.The new study found PFOA to be the most cytotoxic, making up to 42% of the water mixture’s cytotoxicity. In the blood sample, it accounted for nearly 70% of the cytotoxicity, and 38% of the neurotoxicity.The study also looked at PFAS combinations found in sewage sludge used as fertilizer and spread on cropland as a cheap fertilizer. Sewage sludge, or biosolids, is a byproduct of the water-treatment process that is left over when water is separated from human and industrial waste discharged into the nation’s sewer systems. It can contain any of tens of thousands of chemicals sent into the US sewer system.Environmental groups have blasted the practice and sued the EPA for allowing it because biosolids can pollute water and contaminate food.When researchers analyzed the toxicity of biosolid samples collected from a municipal wastewater treatment plant, they found very high toxicities despite low concentrations of PFOA and other PFAS in the sample.“It was more toxic than what we predicted, not necessarily because of other PFAS, but other chemicals in biosolids that can cause toxicity,” Aga said.

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