Category Archives: Plastic Pollution Articles & News

Ahead of talks on a new plastics treaty, nations are split over whether to target reductions in the amount of plastic that is produced or just to try and stop it from polluting land and sea.In their submissions to talks taking place in Paris in May, the majority of European and African countries push for cuts to the supply of plastic while the US and Saudi Arabia focus instead on tackling plastic pollution.
The European Union’s submission says: “While measures on the demand side are expected to indirectly impact the reduction of production levels, efforts and measures addressing supply are equally needed, to cope with increasing plastic waste generation.”
It suggested several options to cut plastic production, including global targets to cut a certain percentage by a given year or nations putting forward their own targets.
The UK calls for governments to adopt legally binding targets to “restrain” plastic production and consumption while the African group lists restraining plastic production and use as an objective.
A group of countries calling themselves the “high-ambition coalition” echo the EU’s suggestion of a global target to reduce production.
The US is not one of the members (light blue) of the High Ambition Coalition to End Plastic Pollution (Photo credit: High Ambition Coalition/Screenshot)
Production taboo
But major oil and gas producers like the USA and Saudi Arabia did not call for cuts in plastic production.
They focus on tackling plastic pollution through recycling and waste disposal.
The US says the treaty should be “country-driven”, “flexible” and that its preamble could include “the beneficial role of plastic, including for human health and food safety”.
In its submission, China – the world’s largest plastic producer – said “a variety of economic and market tools could be adopted in an integrated manner to reduce production and use of plastic products”.
The coalition of small islands (Aosis), many of whom are particularly vulnerable to climate change, did not call for production cuts in their submission either.
UAE minister calls for “phase out” of oil and gas
Their legal adviser Bryce Rudyk told Climate Home that small islands’ focus was reducing the amount of plastic that ends up in the sea.
He said islands were concerned that reductions in plastic production “may actually increase the cost of the plastic that small islands would utilise”.
“We have to think of it as an environmental, economic, social, political trend,” he added. “Kind of like climate change, this is not just a wholly environmental problem”.
Campaigners enthused
Environmental campaigners praised the EU’s proposals. Andres Del Castillo from the Center for International Environmental Law told Climate Home it was a “strong step”. He added that “if the plastics treaty is to meaningfully address plastic pollution, it will be critical for more countries to adopt similar positions that address the early stages of the plastics life cycle”.
Christina Dixon, who follows plastics treaty talks for the Environmental Investigation Agency, said it sent “a clear signal that the EU member states are leaders who are not willing to play with a Paris-style agreement like some of the lower ambition countries have indicated in their submissions”.
But she warned that, as in climate talks, the question of who finances action on plastics is key.
“First step”: Reformers react to World Bank plan to free up climate spending
The EU must support a dedicated multilateral fund to finance action in developing countries, she said.
“It’s great to have targets but if there’s no money for implementation you’re setting up to fail”, she added.
Fossil fuel lifeline
As well as polluting land and sea, plastics are responsible for an estimated 3% of global greenhouse gas emissions through their lifecycle.
If plastics were a country, they would be the fourth biggest polluter after just China, the USA and India.
They are made from oil and gas, potentially offering a lifeline to the sector as climate action cuts demand for fossil fuels as a source of energy.
Dividing lines
At the last set of talks in Uruguay last year, nations were divided along similar lines.
A group calling itself the “high-ambition coalition” argued for a top-down treaty that binds all to certain measures while the US, Saudi Arabia and most of Asia wanted a bottom-up treaty like the Paris Agreement.
The European Union is facing attempts to weaken its power to vote on behalf of its member states in treaty negotiations.
Governments aim to set up a treaty by 2024 and begin holding annual Cop-style talks between treaty members after that.

Environmental advocates are celebrating in Laguna Beach — but it won’t be with balloons.The hilly seaside city known for stunning ocean views and rolling bluffs is weighing a plan to ban the sale and public use of balloons to curtail the risk of devastating wildfires and eliminate a major source of trash floating near the community’s scenic shores.The Laguna Beach City Council is expected to vote Tuesday on the proposal to ban in public the popular mainstay of birthday and graduation parties, whether inflated with helium or not. The move in the community of 23,000 people 50 miles (80 kilometers) southeast of Los Angeles comes as several California beach cities have limited balloons and the state enacted a law to regulate the types made of foil.“This is the beginning,” said Chad Nelsen, chief executive of the nonprofit environmental organization Surfrider Foundation, adding that he sees momentum to weed out balloons that tangle with turtles and sea lions much like he did with the effort to phase out single-use plastic bags. “We’re chipping away at all these things we find and trying to clean up the ocean one item at a time.”ADVERTISEMENTEnvironmental advocates are taking aim at balloons, arguing they’re a preventable cause of coastal pollution that threatens animals and seabirds. Balloon debris can tangle wildlife or be ingested by animals that mistake it for food, and more than 3,000 pieces of balloon litter were picked up on ocean beaches by volunteers in Virginia over a five-year period, according to the NOAA Office of Response and Restoration

We don’t often think of plastics as having “fingerprints.” But they do. And, as we continue to find microparticles in unexpected places — from local anchovy and seabird guts to the deepest trenches of the ocean — identifying those fingerprints is increasingly important.Scientists at the Monterey Bay Aquarium and MBARI recently published an open-access library — a collection anyone can use for free — of the chemical fingerprints of microplastics and other particles that are commonly found in and around the ocean. Researchers can use the library to figure out what kind of plastics are entering the ocean, where they are coming from and what we can do to keep them out in the future.
Scientists estimate that more than 11 million tons of plastic are dumped into the world’s oceans every year — the equivalent of dumping a garbage truck full of plastic into the ocean every minute.
Those plastics get weathered and eroded down into microparticles the size of the tip of a ballpoint pen or nearly-invisible fibers. They are ingested by marine mammals, permanently entering the food chain. Study after study has confirmed that microplastics are a global problem. But to address it, scientists need to know which plastics are moving from land into water.
Collecting chemical ‘fingerprints’
“Identifying microplastics is actually not as easy as it sounds,” said Emily Miller, lead author of the study. “The most accessible tools scientists have — a microscope and our eyes — can be deceiving.”

The chemical fingerprinting technique, called “Raman spectroscopy,” is much more accurate.
It’s fairly straightforward — scientists isolate a piece of suspected microplastic from an animal gut or ocean water or sediment. They shoot a laser at it. The sample scatters the laser light in a characteristic way depending on how its molecules are arranged.
The microscope collects that scattered light and graphs it as a “spectrum.” It looks something like an ECG, with wavy lines and peaks at some points. And it’s unique to the material.
Chris French, the laboratory director at Eurofins S&N Labs and a study coauthor, said getting the spectrum, or the fingerprint, is the easy part. Figuring out what material the fingerprint belongs to is the challenge.
“You can take a spectrum but it’s practically meaningless unless you have a database to go back and do the fingerprint matching,” he said.
Researchers take a spectrum, compare it to libraries of the spectra of known materials and look for a match — just like a detective might compare a fingerprint from a crime scene to a database of human fingerprints.
The fingerprint tells you what the material is, which can point to a source.
“For example, polyethylene is commonly used in disposable water bottles, nylon is a common plastic used to make fishing line, and polyvinyl chloride is frequently used in agricultural irrigation,” said Miller. In some cases, a material could even be traced back to the company that made it.
But the libraries aren’t accessible to everyone.
“Nearly all spectra reference libraries are locked behind expensive paywalls,” said Miller.
Eurofins S&N Labs, a lab that specializes in identifying mystery particles, did the spectroscopy work for the study. S&N Labs has the equipment and the know-how, but even they have to pay for access to a paywalled spectral library. They pay almost $10,000 a year — a cost that gets passed down to their users.
S&N Labs has thousands of users across many industries. But they rarely see academic or marine debris researchers — probably because of the high costs. A single identification request can cost anywhere from $550 to $3,000. So if a researcher opens up a stranded marine animal and wants to know what all those plastic particles are inside, they have to be very selective about which particles they send in.
“It can be prohibitively expensive for research labs,” said French. “And, right now at least, research labs and universities are the only people who seem to be interested in characterizing” marine debris.
“Ocean plastic pollution is a global crisis and we need to remove the barriers so that researchers all over the world can help find solutions,” said Miller.
So the team created a library specific to marine debris that anyone can use. It’s only the second open-access Raman spectroscopy library to date.
What’s in the library?
To build the new library, the researchers tested samples with known identities: pristine plastics in new condition — things like coffee cup lids, electrical tape, pill bottles and styrofoam boxes — plus old, weathered things picked up from fishery environments and beaches — balloons, straws, bike innertubes, dock lines and a Lego tire.
Including the weathered polymers was an important advance for marine debris researchers. “You won’t find anything (in a commercial library) that has been sitting on the beach for three years,” said French.
Miller said when you’re looking at little microparticles collected from the environment they aren’t necessarily all plastic, so they also added biological things to the library — clam, crab and shrimp shells, purple sea urchin spines, kelp, and bone fragments from various marine species.
They scanned 79 materials in all. For each one, the team scanned the sample 100 times to produce 100 spectra, then averaged those scans together to get a single fingerprint. Then they added that fingerprint to the library for anyone to use.
The full library was published in Nature’s Scientific Data journal in December.
“It’s not a huge database that we helped create, but on the other hand, you won’t probably find more than 100 different types of polymers out on the beach,” said French. “I think for what its intended use is it’s a very comprehensive database.”
A week of storms left trash and plastic debris at the Seal Beach jetty in Seal Beach in 2019. (Photo by Paul Bersebach, Orange County Register/SCNG) 
Matthew Savoca, a postdoctoral scholar at Stanford’s Hopkins Marine Station in Pacific Grove who was not involved in the study, commented: “If we’re going to mitigate this issue we need to figure out what the main sources are.”
Savoca studies how organisms interact with their environments and the human impact on those environments. He recently published a study showing that whales off the coast of California coast eat up to 10 million pieces of microplastics a day.
Savoca said including weathered materials was the study’s big, important advance. “What you’d find in the environment are materials that are degraded and fragmented and weathered,” he said. “The open-access part is nice, but I would argue that the libraries that exist are not super realistic to what you’d find in the real world, and this is bringing us closer to what you’d find in the real world,” said Savoca.
The Monterey-based researchers plan to use the library to identify particles pulled from the deepest parts of the Monterey Bay. The ultimate goal: keeping plastic out of the ocean in the first place.
“Once we have these plastic identities, we can trace the source of the pollution, and finally we can begin to manage the pollution pathway that enters the ocean,” said Miller.
Some interventions and management strategies have already begun to work.
States with “container deposit legislation,” or “bottle bills,” have much smaller percentages of beverage containers in their marine debris, based on data from NOAA’s Marine Debris Program. In other words, regulating specific plastics does help to keep them out of the ocean.
Miller hopes that more labs will continue to create and add to open-source libraries like this one. As libraries grow, scientists will have to standardize things like data collection and processing protocols so that the spectra are comparable and useful.
“The microplastics research community is in the beginning phase of making this type of research accessible to all,” she said. “We are putting this open-source library out into the world for others to use, but it is only one step. We need other community members to continue to contribute spectral libraries.”
The field of studying microplastics in the environment only emerged over the last decade, but it’s growing at a very rapid rate. “The community is growing so quickly that more and more people are going to find this useful over the coming months and years,” said Savoca. “I think it’s great that people in Monterey Bay are doing this work because it’s a really great system to study this problem in.”

United Nations members gather Monday in New York to resume efforts to forge a long-awaited and elusive treaty to safeguard the world’s marine biodiversity. Nearly two-thirds of the ocean lies outside national boundaries on the high seas where fragmented and unevenly enforced rules seek to minimize human impacts. The goal of the U.N. meetings, running through March 3, is to produce a unified agreement for the conservation and sustainable use of those vast marine ecosystems. The talks, formally called the Intergovernmental Conference on Marine Biodiversity of Areas Beyond National Jurisdiction, resume negotiations suspended last fall without agreement on a final treaty. “The ocean is the life support system of our planet,” said Boris Worm, a marine biologist at Canada’s Dalhousie University. “For the longest time, we did not feel we had a large impact on the high seas. But that notion has changed with expansion of deep sea fishing, mining, plastic pollution, climate change,” and other human disturbances, he said.ADVERTISEMENTThe U.N. talks will focus on key questions, including: How should the boundaries of marine protected areas be drawn, and by whom? How should institutions assess the environmental impacts of commercial activities, such as shipping and mining? And who has the power to enforce rules?“This is our largest global commons,” said Nichola Clark, an oceans expert who follows the negotiations for the nonpartisan Pew Research Center in Washington, D.C. “We are optimistic that this upcoming round of negotiations will be the one to get a treaty over the finish line.”The aim of the talks is not to actually designate marine protected areas, but to establish a mechanism for doing so. “The goal is to set up a new body that would accept submissions for specific marine protected areas,” Clark said.Marine biologist Simon Ingram at the University of Plymouth in England says there’s an urgent need for an accord. “It’s a really pressing time for this — especially when you have things like deep-sea mining that could be a real threat to biodiversity before we’ve even been able to survey and understand what lives on the ocean floor,” Ingram said.Experts say that a global oceans treaty is needed to actually enforce the U.N. Biodiversity Conference’s recent pledge

Allegheny County Council could consider a ban on single-use plastic bags at checkouts. The council’s Committee on Sustainability and Green Initiatives held a hearing about the issue on Wednesday, where they heard from experts and residents about how they might address plastic pollution in the county.According to environmental advocacy group Penn Environment, Pennsylvanians use an estimated 4.75 billion single-use plastic bags annually, few of which are ever properly recycled. Plastic also breaks up into microplastics, tiny particles of plastic that have been found in local waterways and even in humans.Of the nearly 7,000 pounds of trash collected during an audit by Allegheny CleanWays in 2019, the “vast majority” of it was plastic, said the group’s executive director Myrna Newman.“Because we use [plastic products] in so many parts of our lives, and often for just a few minutes before throwing them away, there is no ‘away,’” Faran Savitz, a zero waste advocate with Penn Environment, told the committee. “If it’s ending up in a landfill, if it’s ending up in our rivers, our parks, upstream, up street, these plastic products are hurting us.”Pittsburgh City Council passed legislation to ban the use of single-use plastic bags in city limits last year. It will go into effect this spring.Councilor Erika Strassburger, who sponsored the bill, walked committee members through the process City Council undertook before passing their ban. After months of discussions with unions, environmental groups, business owners and others, the final legislation banned single-use plastic bags. Instead, shoppers or customers getting takeout from a restaurant must bring their own reusable bag or pay a 10-cent fee to receive a paper bag.County Council members said they still have a lot of questions about how a similar ban would be successfully implemented in Allegheny County, which includes 130 municipalities. But Council member Anita Prizio, who chairs the Sustainability and Green Initiatives committee, said council is “very seriously” considering a ban on single-use plastic bags.

One third of all second-hand clothing shipped to Kenya in 2021 was “plastic waste in disguise”, creating a slew of environmental and health problems for local communities, a new report said Thursday.Every year, tonnes of donated clothing is sent to developing countries, but an estimated 30 percent of it ends up in landfills — or flooding local markets where it can crowd out local production.A new report shows that the problem is having grave consequences in Kenya, where some 900 million pieces of used clothing are sent every year, according to the Netherlands-based Changing Markets Foundation.Much of the clothing shipped to the country is made from petroleum-based materials such as polyester, or are in such bad shape they cannot be donated.They may end up burning in landfills near Nairobi, exposing informal waste pickers to toxic fumes. Tonnes of textiles are also swept into waterways, eventually breaking down into microfibres ingested by aquatic animals.”More than one in three pieces of used clothing shipped to Kenya is a form of plastic waste in disguise and a substantial element of toxic plastic pollution in the country,” the report said.The research was based on customs data as well as fieldwork by non-profit organisation Wildlight and the activist group Clean Up Kenya, which conducted dozens of interviews.Some of the clothing items were stained with vomit or badly damaged, the report found, while others had no use in Kenya’s warmer climate.”I have seen people open bales with skiing gear and winter clothes, which are of no use to most Kenyans,” Betterman Simidi Musasia, Clean Up Kenya founder, told AFP.- ‘Enormous waste problem’ -Between 20 and 50 percent of all donated clothing was not of a sufficient quality to be sold on the local secondhand market, the report found.Unwearable items might be turned into industrial wipes or cheap fuel for peanut roasters, swept into the Nairobi river, scattered around the market or sent to immense plastic graveyards outside the capital, such as the Dandora landfill.Story continuesSeveral waste pickers working at Dandora said they contracted breathing and asthma issues by inhaling smoke from burning plastic at the site, according to the report.Musasia said items should be better sorted at the point of donation before being shipped to Kenya, instead of being blindly passed on, to try and prevent the problem at the source.Experts say the problem of clothing waste has been exacerbated by the fast fashion boom in wealthier nations, where items — many made from synthetic fibres — might be worn only a few times before being discarded.The report called for the use of non-toxic and sustainable materials in textile manufacturing, and the establishment of more robust extended producer responsibility schemes around the world. “The Global North is using the trade of used clothing as a pressure-release valve to deal with fast fashion’s enormous waste problem,” it said.lam/jv/klm/imm

Obesity is on the rise almost everywhere, with more overweight and obese than underweight people, globally. According to accepted wisdom, blame lies squarely with overeating and insufficient exercise. A small group of researchers is challenging such ingrained assumptions, however, and shining a spotlight on the role of chemicals in our expanding waistlines.‘There are at least 50 chemicals, probably many more, that literally make us fatter,’ says Leonardo Trasande, an environmental health scientist at New York University in the US. An obesogen is a chemical that makes a living organism gain fat. Notable examples include bisphenol A, certain phthalates and most organophosphate flame retardants. They can push organisms to make new fat cells and/or encourage them to store more fat. Almost all of us often encounter such chemicals every day.

Over the past 20 years, calorie consumption is flat – but obesity has gone up

This may even help explain some discrepancies in data. Obesity rates have tripled since the 1970s, ticking up in the US from 30.5% in 2000 to 42.4% in 2018. ‘Over the past 20 years, calorie consumption is flat, or gone down slightly [in the US],’ according to Bruce Blumberg, a cell biologist at the University of California Irvine in the US. ‘But obesity has gone up.’ And it is not just humans. Body weights of animals such as dogs, cats, rodents and non-human primates – in research colonies and living feral – are also reported to be increasing. Blumberg and others are on a mission to persuade clinicians and others to take contributions to obesity from chemicals more seriously.
Weight gain
The hypothesis that chemicals encourage weight gain is perhaps not surprising, given that an expanded waistline is a side effect of some medicines. Antidepressants such as selective serotonin receptor inhibitors are associated with weight gain, and anti-diabetic drugs such as rosiglitazone were long known to add a few pounds.

Blumberg coined the term obesogen in 2006, when his lab showed that tributyltin chloride promoted fat formation in mice. ‘Mice we expose to tributyltin don’t eat more, and they don’t exercise less than animals not exposed to it,’ says Blumberg. ‘But they use calories differently – they store more as fat. That’s very relevant to humans.’ Exposure in utero leads to ‘strikingly elevated lipid accumulation’ in fat deposits, liver and testis of in neonate mice. Another early study showed that an estrogen drug (diethylstilbestrol) in pregnant mice significantly increased body weight of their offspring – as adults.
Starvation was a constant threat to our ancestors. ‘Weight gain is important to the survival of the species,’ says Robert Lustig, emeritus professor of endocrinology at the University of California, San Francisco, and campaigner against childhood obesity. ‘There are multiple paths to it.’ Some obesogenic chemicals flick biochemical switches to store fat for a rainy day.
Lusting and others described obesogen exposure as an underappreciated and understudied factor in the obesity pandemic, in a recent review of causal links.1 Dozens of animal studies are cited. Studies revealed, for example, that mice fed DEHP (bis(2-ethylhexyl) phthalate) consume more food, pile on weight and store more belly fat. We couldn’t ethically give people DEHP, but people are nonetheless exposed to it every day: it improves the flexibility of polyvinyl chloride (PVC) and is used in floor and wall coverings, food containers, toys and cosmetics.
While you can’t dose people, you can analyse blood for chemical contaminants. Those with high phthalate levels are more likely to gain weight over the next 10 years, research has shown. Perfluoroalkyl substances (PFASs) – so-called forever chemicals – are also obesogens. They are villains in a clinical trial in the US (POUNDS Lost) investigating weight loss in 600 overweight and obese adults on one of four diets. Plasma concentrations of PFASs did not influence weight loss during six months of dieting, but women with high levels at the start of the trial experienced significantly more weight regain.
Mechanisms
Fat tissue expands due to increased cell number and size during foetal development, childhood and adolescence, while fat cell (adipocytes) numbers remain stable during adulthood, so long as weight remains stable. The primary regulator of fat cell formation (adipogenesis) is considered to be peroxisome proliferator activated receptor gamma (PPAR-).

If you express this receptor on a mesenchymal stem cell, it becomes a pre-adipocyte, which are important cells that can become bone cells, immune cells or fat cells. If PPAR- then becomes activated by long-chained fatty acids, it becomes a fat cell. When triggered inside an existing fat cell, the cell accumulates more fat. ‘If you activate the receptor well, with full agonists, then the cells generally become healthy white fat cells,’ explains Blumberg.
This receptor has a large promiscuous pocket that is vulnerable to hacking by multiple obesogenic ligands. One of Blumberg’s early discoveries was that tributylin activated PPAR-He later found that it hits two parts of PPAR- at the same time, making white fat cells good at storing fat, but not good at releasing it. ‘The worst thing you could have – an unhealthy fat cell that stores but doesn’t give up its fat,’ Blumberg explains.
A long list of environmental contaminants bind to this fat receptor – plasticisers, phthalates and BPA and its analogues; flame retardants; and per- and poly-fluoroalkyl substances (PFAS). All are obesogens. But this is not the only route. Obesogens can alter appetite control, impact the microbiome or change how much energy your body burns at rest (basal metabolic rate) via the thyroid hormone receptor, say researchers. Resting metabolic rate represents 70% of an average person’s energy expenditure, so lowering it has a major impact on weight. ‘People with the highest levels of perfluorinated chemicals have lower resting metabolic rates, a study has shown, and regain weight more quickly,’ notes Blumberg.

Phthalates can change how the body processes a meal and turn it into fat 

Also susceptible to obesogenic chemicals are oestrogen and androgen receptors, glucocorticoid receptors and the retinoid X receptor, which promotes fat cell formation and the proliferation of precursor fat cells. Bisphenol A and its analogues, says Blumberg, ‘can target probably a dozen different pathways in the body’, for example. In vitro, BPA influenced PPAR-and lipid accumulation, while exposing unborn male mice to low dose – but not high dose – BPA stoked up body weight, food intake and number of fat cells, as well as insulin regulation, the enzyme needed to control blood sugar.
Binding fat cell receptors, fully or partially, can even shift a person’s metabolism. ‘Imagine you’ve had a good workout, you’ve eaten a good protein meal, and you are thinking you are going to gain some muscle,’ says Trasande. But chemicals such as phthalates can ‘change how the body processes a meal and ultimately turn it into fat or carbohydrate instead’, he warns. This turns on its head the simplistic story of overeating fat leading to a flabby girth.
Calorie counting
The obesogenic community is adamant that calorie counting has led clinicians and the public astray. And they are starting to spread their beliefs to the medical community. If you relegate weight gain to simple maths, energy in and energy out, then you gain weight if you eat too much and exercise too little. This is the energy balance model, and its major premise is that a calorie is a calorie, and you must not end up with too many. ‘It’s about two behaviours, gluttony and sloth, and therefore if you are fat, it is your fault,’ Lustig sums up. But he says there’s little evidential support.

Another proponent of the obesogen hypothesis is Jerrold Heindel, formerly involved in grant funding decisions for environmental chemicals and disease at the National Institutes of Health in the US. He became interested in the early 2000 . Now retired, he was pivotal in the recent publication of three review papers summarising evidence on obesogens.
Like others, he is frustrated about current approaches to obesity. While exercise improves health, it does not cure obesity, and dieting results in weight loss that is rarely sustained. Yet clinicians remain focused on diets, drugs and surgery. ‘If all that worked, we should see a decline in obesity, but we are not seeing a decline at all. It’s going up, especially in children,’ says Heindel. What many nutritionists miss is a cause of increased eating, which is obesogenic chemicals that alter sensitivity to weight gain, he adds.
His colleague Lustig views energy storage as coming first and increased food intake following. ‘In this energy storage model,’ he says, ‘biochemistry comes first, then the behaviours.’ He arrived at this conclusion partly from a study of children cured of a brain tumour, but obese because a drug ramped up their insulin levels. This pushed energy into fat, leaving them lethargic and hungry.
Ubiquitous foes
Obesogens are ubiquitous in our environment. They are present in dust, water, processed foods, food packaging, cosmetics and personal care products, but also furniture and electronics, air pollutant, pesticides, plastics and plasticisers. Phthalates and organophosphates can be detected in around 90% of Americans, notes Chris Kassotis, a toxicologist at Wayne State University in Detroit, US. ‘They’re high-production chemicals, pretty ubiquitous, with high human exposure,’ he notes.
Kassotis has taken an interest in the finer things in life – specifically, house dust, a complex mixture of hundreds, sometimes thousands, of chemicals. In 2017, Kassotis reported that house dust impacted mouse fat cells. Ten of 11 extracts spurred triglyceride accumulation in preadipocyte mouse cells.
‘Really low levels of dust were able to drive the development of fat cells in our cell model,’ recalls Kassotis. Around 20μg of dust impacted the fat cells, a small amount considering the Environmental Protection Agency in the US estimates that a child consumes about 50mg of dust per day. A subsequent study found that about three-quarters of dust samples antagonised a thyroid receptor, and about one-fifth activated PPAR-Ultimately, the Karssotis lab tested over 350 samples and around 90% showed activity in mouse fat cells.

Environmental contaminants are not the only source. Many ingredients added to processed foods are sources too, say obesogen researchers. ‘When we add sugar to make a food taste better, we’re making it more obesogenic,’ says Blumberg. Table sugar, sucrose, consists of one glucose and one fructose unit, with fructose found naturally in fruit, honey, and root vegetables. Fructose is the most concerning, as far as Lustig is concerned. ‘It inhibits mitochondrial function, which is necessary to burn energy,’ he explains. ‘If you don’t burn it, then it gets turned into fat and stored.’
Fructose was traditionally consumed around harvest time, a natural signal for the body to store fat in the liver in preparation for the coming winter, says Lustig: ‘This makes evolutionary sense, but the problem is that it is now available all the time.’
Some foods advertised as low calorie or for weight loss may contain obesogens. ‘Diet sweeteners cause weight gain,’ asserts Lustig, ‘because they raise your insulin levels.’ Research in animals and humans show a positive link between insulin levels and obesity. The addition of artificial sweeteners such as aspartame, saccharin and sucralose to foods has successfully reduced sugar intake, but not obesity levels.
In one study, children born to mothers in Canada who regularly consumed non-nutritive sweetened drinks had a higher body mass index and more fat tissue by age three. The researchers then fed sucrose, aspartame or sucralose to pregnant mice. Male mice born to mothers on aspartame and sucralose showed body fat rises of 47% and 15%, respectively.
Also suspected to be obesogens are the flavour enhancer monosodium glutamate, food emulsifiers such as dioctyl sodium sulfosuccinate, and parabens used as preservatives in foods and in personal care products. Some food additives such as carboxymethylcellulose are believed to increase body weight – at least in mice – by altering the microbiota in the gut. The additive thickens foods and stabilises emulsions such as in ice cream products. Reducing exposures to such common substances will be challenging.
Although there is widespread evidence from animal models, some experts in other fields like toxicology are not fully convinced. They make the point that environmental obesogens like these are generally low potency, which when combined with low exposures to most people, means there is very low risk. And with controlled experiments difficult to carry out in humans, they may remain unconvinced. Obesogen researchers counter that many scientists don’t yet fully consider endocrine disruptors to be important factors.
Regarded safe
Regulation is also a struggle. ‘We operated under the assumption that only the dose makes the poison,’ says Trasande. This has allowed endocrine-disrupting chemicals – of which obesogens are a subset – to dodge regulations because their effects can be subtle and occur at low doses. Parts per billion of tributyltin influence snails and fish. The same is true of fat cells. ‘Tributyltin causes effects at doses which people are exposed to, such as 20ppb,’ says Blumberg. ‘You can make animals obese at those levels.’ This sets a high bar from those in the field who wish for policy action against these chemicals. ‘[Researchers] are findings effects below the doses that governments say is safe for many of these chemicals,’ warns Heindel.

There are hundreds of endocrine-active chemicals in plastics

Also, many food additives that are obesogens or suspected obesogens are designated ‘generally regarded as safe’ by the Food and Drug Administration in the US. This applies to a substance used in food prior to 1958 or with a substantial history of consumption. ‘They were never tested,’ says Blumberg, ‘but regulators should go back and test them.’ The recent proposal by the European Food Safety Authority (EFSA) to lower the reference dose of BPA 100,000-fold is a case in point, according to Blumberg – ‘it brings it into line with what the endocrine disrupting community has been saying for years’. Such ‘innocent until proven guilty chemicals’ are a problem, warns Trasande.
Consumers, nevertheless, can reduce their exposures. Among suggestions are to reduce use of plastic containers and packaging, and never microwave with plastic. ‘Do not eat packaged processed food. It’s full of obesogens. Buy fresh ingredients and make a meal,’ advises Blumberg. A Norwegian study found that one-third of the chemicals in 34 plastic consumer products disrupted the development of fat precursor cells in vitro. Analyses revealed a motley assortment of additives, breakdown products and manufacturing residues. ‘There are hundreds of endocrine-active chemicals in plastics,’ says Blumberg. Glass is a healthier alternative, he adds. According to Trasande, studies show that reducing canned food consumption reduces blood bisphenol levels. Cast iron and stainless steel are alternatives to nonstick cookware, which is made using PFOA.
Assessing how much chemicals may be contributing to the obesity epidemic is difficult. ‘There’s a tip of the iceberg phenomenon. There’s what we know, and what we don’t know, but the evidence is evolving,’ says Trasande. It is not that obesogens are the cause of the obesity pandemic, but a contributing factor. There is little monitoring of chemical levels within people, and government action is needed here. ‘We need to know who is exposed and what the critical times of life are,’ says Blumberg. Once programmed to have a certain number of fat cells, you will never have less.
Unfortunately, there are worrying signs of possible impacts running down generations. Mice whose grandparents were exposed to tributyltin in utero are affect. One study showed mother mice exposure to low doses of tributyltin during pregnancy predisposes (unexposed) male mice in the fourth generation to obesity via a so-called ‘thrifty phenotype,’ meaning a propensity to store fat and hold onto it during fasting. ‘We don’t have human data for transgenerational effects yet, but you can see how scary that would be,’ says Heindel. ‘Increased obesity in children is still due to poor diet and exposure during pregnancy and childhood, but maybe some of that exposure was through their grandmother.’
While obesogens are not the sole cause of the obesity problem, these chemicals deserve more attention and potentially stricter regulation. And those advocating action say that the obesogen hypothesis offers a preventive approach, so that reducing exposures should reduce the incidence or severity of obesity.
Anthony King is a science writer based in Dublin, Ireland

In the 1930s, the DuPont company created the world’s first nylon, a synthetic polymer made from petroleum. The product first appeared in bristles for toothbrushes, but eventually it would be used for a broad range of products, from stockings to blouses, carpets, food packaging, and even dental floss.

Nylon is still widely used, but, like other plastics, it has environmental downsides: it is made from a nonrenewable resource; its production generates nitrous oxide, a potent greenhouse gas; it doesn’t biodegrade; and it sheds microfibers that end up in food, water, plants, animals, and even the clouds.

Now, however, a San Diego-based company called Genomatica is offering an alternative: a so-called plant-based nylon made through biosynthesis, in which a genetically engineered microorganism ferments plant sugars to create a chemical intermediate that can be turned into nylon-6 polymer chips, and then textiles. The company has partnered with Lululemon, Unilever, and others to manufacture this and other bio-based products that safely decompose.
“We are at the start of a sustainable materials transition that will reinvent the products we use every day and where they come from,” says Christophe Schilling, Genomatica’s CEO.

In September, President Biden launched a $2 billion biotechnology and biomanufacturing initiative.

Using living organisms to create safe materials that break down completely in the environment — where they can act as nutrients or feedstock for new growth — is just one example of a burgeoning global movement working toward a so-called bioeconomy. Its goal isn’t limited to replacing plastics but takes aim at all conventional synthetic products — including chemicals, concrete, and steel — that are toxic to make or use, difficult to recycle, and have outsize carbon footprints. In their place will come products made from plants, trees, or fungi — materials that, at their end of life, can be safely returned to the Earth or recycled again and again. The bioeconomy is still small, in the global scheme of things, but the push to turn successful research into manufactured products is growing, propelled by several factors.

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