Science

Microplastics discovered in human and dog testes

Published

8 months ago

May 22, 2024

Microplastics discovered in human and dog testes

Researchers have located one more anatomical organ where microplastics — of all shapes and constituents — are found: human testes.

And although they can’t say for sure, they suspect the presence of these jagged bits and strands of polymers such as polyethylene, polyvinyl chloride and polystyrene could be — in part — behind a global trend in diminishing sperm quality and quantity.

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In 2022, a team of researchers published a paper showing that global sperm counts fell about 1.2% per year between 1973 and 2018. From the year 2000, that rate accelerated to more than 2.6% per year.

“What I think will grab people’s attention with this study is the fact that plastic is in the testicles and potentially contributing to disarray in the function of the testicles,” said Leonardo Trasande, a pediatrician and public policy expert at New York University’s Grossman School of Medicine and Wagner School of Public Service.

“What should have gotten people excited all along is the fact that we’ve known that the invisible chemicals — the phthalates, the bisphenols and the PFAS that are used in plastic materials — are already known to be problems,” he said. “And so if this is what it takes to get people’s attention, I’m a bit sad. Because we already had enough evidence that plastics were bad for testicular function.”

Others, including Philip Landrigan, director of the Program for Global Public Health and the Common Good at Boston College, said the study was “consistent with a whole series of papers that have come out now in the last few years” showing these particles in a variety of organs, including the heart, liver, lungs and brain.

“It’s no surprise that microplastics are in the testes. The plastic is ubiquitous in today’s world, the stuff breaks down, and the smaller the particle, the more easily it can move into and throughout the human body,” he said.

Xiaozhong Yu, a professor of environmental health at the University of New Mexico — and an author on this latest research — said he’d been researching the effects of different chemicals on sperm production for years, and it was only recently that a colleague suggested he look for microplastics in testes.

“I said, ‘Are you joking?’,” he said, recalling the conversation, explaining he was pretty certain he wouldn’t find microplastics in tests because — like the brain — these sperm-generating factories are insulated by a protective barrier.

Nevertheless, they gave it a go.

They started by trying it out in dog testes. They were able to acquire 47 from neutering clinics. (The pet owners all provided permission.)

They found microplastics in small dogs, big dogs, young dogs and old dogs. The plastic bits were in every dog testis they examined. The number ranged from 2.36 micrograms per gram to 485.77 micrograms per gram. The average was 122.63 micrograms per gram, and 12 polymers were identified. The most abundant were polyethylene — the material found in plastic packaging, films and bottles — and polyvinyl chloride — a material found in most household water pipes.

He said he immediately went back to investigate their quality control. Maybe the testes had become contaminated at some point during the procedure or testing?

He and his team were able to rule that out, although Landrigan noted that contamination was still possible — unless everything, from procurement to analysis had been done in a “clean” room devoid of all plastic.

Yu and his team then decided to look at human samples. In the end, they were able to examine 23 testes from men ages 16 to 88. The tissue was acquired from males who had died in accidents and whose testes had been preserved post-autopsy. He said all samples were from men who had died in 2016 — made available following a seven-year storage requirement, after which time such samples are usually discarded.

Once again, they found microplastics in every sample they examined, and as with the dog testes, there was wide variation — from 161.22 micrograms per gram to 695.94 micrograms per gram, with an average of 328.44 micrograms per gram — nearly three times greater than what they found in dogs.

The microplastics in human testes were also composed of a variety of polymers, with polyethylene being the most common, followed by ABS (acrylonitrile, butadiene and styrene monomers — which is used to make a variety of products, including toys, automotive parts, medical equipment and consumer electronics), N66 (a kind of nylon), polyvinyl chloride and others.

The researchers also noted a correlation between the concentrations of PVC and polyethylene and testes weight: The higher the concentration, the lower the weight.

“Generally, a decreased testis weight is indicative of reduced spermatogenesis,” wrote the authors in the paper.

Yu said the difference in humans and dogs between polymer types — with dogs showing higher concentrations of PVC than men — likely has to do with lifestyle differences. He said consumer trends show a general aversion to eating or drinking out of bottles and foodware made from PVC, which contains bisphenol A — an additive that has been associated with health and developmental harm.

However, he began looking at dog toys, and noticed many of them are made from this kind of plastic.

“People are choosing to avoid it,” he said. But the market hasn’t budged in the same way for dogs.

Asked what the major route of exposure was for dogs and people, he said “microplastics are everywhere — in the air, in the drinking water, in the food, in our clothes. We don’t exactly know what is the most probable route. But they are everywhere.”

He also noticed variation within the groups. Dog testes acquired from public veterinary clinics showed higher levels of microplastics than those from private clinics, “potentially reflecting the influence of socioeconomic differences on the living environments and lifestyles of dogs.”

The researchers were also not able to find a correlation between age and microplastic concentration — a finding that surprised them. (Although men over the age of 55 had the least amount).

“The absence of a distinct age-dependent accumulation of microplastics in human testes may be due to unique physiological and biological processes of spermatogenesis,” they wrote, noting the continual renewal and release of sperm, which could “help mitigate the buildup of microplastics over time.”

That hypothesis, they noted, was supported by the presence of microplastics in human seminal fluid.

“The reality is that the petrochemical industry has gotten a pass all these years,” said Trasande, the NYU professor. “We know that plastics come from the petrochemical industry … and it’s no secret that we have paid as a society by letting the petrochemical industry pollute us. Now we’re paying the consequences. And if we don’t reverse course fairly quickly, we will have an even bigger problems before us because plastic consumption is growing, not slowing down.”

Landrigan agreed and noted that nations were currently in negotiations to sign a treaty that would curb the use of plastic and cap production.

“Plastic production is increasing exponentially,” he said noting that it’s increased more than 200-fold since the 1950s. He said plastic production is on a trajectory to double by 2040 and triple by 2060. There have been a total of about 8 billion tons of plastic produced since 1950, he said, and about 6 billion tons is “floating around us, most of it in the form of microplastics.”

He said the anatomical location of this latest microplastic discovery may hit close to home for lawmakers, who until this time, have not been too concerned.

He said he’d had to testify in the Senate several years ago about endocrine disruptors, and mentioned that sperm quantity was reduced in men who’d been exposed.

“Two senators sat back and unconsciously crossed their legs,” he said. “The body language was amazing.”

Science

2024 Brought the World to a Dangerous Warming Threshold. Now What?

Published

5 hours ago

January 10, 2025

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2024 Brought the World to a Dangerous Warming Threshold. Now What?

Source: Copernicus/ECMWF

Note: Temperature anomalies relative to 1850-1900 averages.

At the stroke of midnight on Dec. 31, Earth finished up its hottest year in recorded history, scientists said on Friday. The previous hottest year was 2023. And the next one will be upon us before long: By continuing to burn huge amounts of coal, oil and gas, humankind has all but guaranteed it.

The planet’s record-high average temperature last year reflected the weekslong, 104-degree-Fahrenheit spring heat waves that shuttered schools in Bangladesh and India. It reflected the effects of the bathtub-warm ocean waters that supercharged hurricanes in the Gulf of Mexico and cyclones in the Philippines. And it reflected the roasting summer and fall conditions that primed Los Angeles this week for the most destructive wildfires in its history.

“We are facing a very new climate and new challenges, challenges that our society is not prepared for,” said Carlo Buontempo, director of the Copernicus Climate Change Service, the European Union monitoring agency.

But even within this progression of warmer years and ever-intensifying risks to homes, communities and the environment, 2024 stood out in another unwelcome way. According to Copernicus, it was the first year in which global temperatures averaged more than 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above those the planet experienced at the start of the industrial age.

For the past decade, the world has sought to avoid crossing this dangerous threshold. Nations enshrined the goal in the 2015 Paris agreement to fight climate change. “Keep 1.5 alive” was the mantra at United Nations summits.

Yet here we are. Global temperatures will fluctuate somewhat, as they always do, which is why scientists often look at warming averaged over longer periods, not just a single year.

But even by that standard, staying below 1.5 degrees looks increasingly unattainable, according to researchers who have run the numbers. Globally, despite hundreds of billions of dollars invested in clean-energy technologies, carbon dioxide emissions hit a record in 2024 and show no signs of dropping.

One recent study published in the journal Nature concluded that the absolute best humanity can now hope for is around 1.6 degrees of warming. To achieve it, nations would need to start slashing emissions at a pace that would strain political, social and economic feasibility.

But what if we’d started earlier?

By spewing heat-trapping gases into the atmosphere, humankind has lifted global temperatures to record highs.

If nations had started reducing emissions in 2005, they could have made gradual cuts to limit warming to 1.5 degrees.

Starting in 2015, when the Paris agreement was adopted, would have required steeper cuts.

Starting today would require cuts so drastic as to appear essentially impossible.

“It was guaranteed we’d get to this point where the gap between reality and the trajectory we needed for 1.5 degrees was so big it was ridiculous,” said David Victor, a professor of public policy at the University of California, San Diego.

The question now is what, if anything, should replace 1.5 as a lodestar for nations’ climate aspirations.

“These top-level goals are at best a compass,” Dr. Victor said. “They’re a reminder that if we don’t do more, we’re in for significant climate impacts.”

The 1.5-degree threshold was never the difference between safety and ruin, between hope and despair. It was a number negotiated by governments trying to answer a big question: What’s the highest global temperature increase — and the associated level of dangers, whether heat waves or wildfires or melting glaciers — that our societies should strive to avoid?

The result, as codified in the Paris agreement, was that nations would aspire to hold warming to “well below” 2 degrees Celsius while “pursuing efforts” to limit it to 1.5 degrees.

Even at the time, some experts called the latter goal unrealistic, because it required such deep and rapid emissions cuts. Still, the United States, the European Union and other governments adopted it as a guidepost for climate policy.

Christoph Bertram, an associate research professor at the University of Maryland’s Center for Global Sustainability, said the urgency of the 1.5 target spurred companies of all kinds — automakers, cement manufacturers, electric utilities — to start thinking hard about what it would mean to zero out their emissions by midcentury. “I do think that has led to some serious action,” Dr. Bertram said.

But the high aspiration of the 1.5 target also exposed deep fault lines among nations.

China and India never backed the goal, since it required them to curb their use of coal, gas and oil at a pace they said would hamstring their development. Rich countries that were struggling to cut their own emissions began choking off funding in the developing world for fossil-fuel projects that were economically beneficial. Some low-income countries felt it was deeply unfair to ask them to sacrifice for the climate given that it was wealthy nations — and not them — that had produced most of the greenhouse gases now warming the world.

“The 1.5-degree target has created a lot of tension between rich and poor countries,” said Vijaya Ramachandran, director for energy and development at the Breakthrough Institute, an environmental research organization.

Costa Samaras, an environmental-engineering professor at Carnegie Mellon University, compared the warming goals to health officials’ guidelines on, say, cholesterol. “We don’t set health targets on what’s realistic or what’s possible,” Dr. Samaras said. “We say, ‘This is what’s good for you. This is how you’re going to not get sick.’”

“If we were going to say, ‘Well, 1.5 is likely out of the question, let’s put it to 1.75,’ it gives people a false sense of assurance that 1.5 was not that important,” said Dr. Samaras, who helped shape U.S. climate policy from 2021 to 2024 in the White House Office of Science and Technology Policy. “It’s hugely important.”

Scientists convened by the United Nations have concluded that restricting warming to 1.5 degrees instead of 2 would spare tens of millions of people from being exposed to life-threatening heat waves, water shortages and coastal flooding. It might mean the difference between a world that has coral reefs and Arctic sea ice in the summer, and one that doesn’t.

Each tiny increment of additional warming, whether it’s 1.6 degrees versus 1.5, or 1.7 versus 1.6, increases the risks. “Even if the world overshoots 1.5 degrees, and the chances of this happening are increasing every day, we must keep striving” to bring emissions to zero as soon as possible, said Inger Anderson, the executive director of the United Nations Environment Program.

Officially, the sun has not yet set on the 1.5 target. The Paris agreement remains in force, even as President-elect Donald J. Trump vows to withdraw the United States from it for a second time. At U.N. climate negotiations, talk of 1.5 has become more muted compared with years past. But it has hardly gone away.

“With appropriate measures, 1.5 Celsius is still achievable,” Cedric Schuster, the minister of natural resources and environment for the Pacific island nation of Samoa, said at last year’s summit in Azerbaijan. Countries should “rise to the occasion with new, highly ambitious” policies, he said.

To Dr. Victor of U.C. San Diego, it is strange but all too predictable that governments keep speaking this way about what appears to be an unachievable aim. “No major political leader who wants to be taken seriously on climate wants to stick their neck out and say, ‘1.5 degrees isn’t feasible. Let’s talk about more realistic goals,’” he said.

Still, the world will eventually need to have that discussion, Dr. Victor said. And it’s unclear how it will go.

“It could be constructive, where we start asking, ‘How much warming are we really in for? And how do we deal with that?’” he said. “Or it could look very toxic, with a bunch of political finger pointing.”

Methodology

The second chart shows pathways for reducing carbon emissions that would have a 66 percent chance of limiting global warming this century to 1.5 degrees Celsius above the preindustrial average.

Science

U.S. Efforts to Cut Emissions Stalled in 2024 as Power Demand Surged

Published

13 hours ago

January 9, 2025

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U.S. Efforts to Cut Emissions Stalled in 2024 as Power Demand Surged

America’s efforts to cut its climate change pollution stalled in 2024, with greenhouse gas emissions dropping just a fraction, 0.2 percent, compared to the year before, according to estimates published Thursday by the Rhodium Group, a research firm.

Despite continued rapid growth in solar and wind power, emissions levels stayed relatively flat last year because demand for electricity surged nationwide, which led to a spike in the amount of natural gas burned by power plants.

The fact that emissions didn’t decline much means the United States is even further off-track from hitting President Biden’s goal of slashing greenhouse gases 50 percent below 2005 levels by 2030. Scientists say all major economies would have to cut their emissions deeply this decade to keep global warming at relatively low levels.

Since 2005, United States emissions have fallen roughly 20 percent, a significant drop at a time when the economy has also expanded. But to meet its climate goals, U.S. emissions would need to decline nearly 10 times as fast each year as they’ve fallen over the past decade. That seems increasingly unlikely, experts say, especially since President-elect Donald J. Trump has promised to dismantle Mr. Biden’s climate policies and promote the production of fossil fuels, the burning of which generates greenhouse gases.

“On the one hand, it is notable that we’ve now seen two years in a row where the U.S. economy grew but emissions went down,” said Ben King, an associate director at the Rhodium Group. “But it’s far from enough to achieve our climate targets.”

The biggest reason that U.S. emissions have fallen in recent years is that electric utilities have been retiring their older, dirtier coal-fired power plants and replacing them with cheaper and less-polluting natural gas, wind and solar power. That trend mostly continued last year, with a few unexpected ups and downs.

The nation’s demand for electricity, which has stayed more or less flat for two decades, suddenly jumped by roughly 3 percent in 2024, in large part because scorching heat during the summer caused many Americans to crank up their air-conditioners. A smaller factor was that tech companies have been building more energy-hungry data centers in states like Virginia and Texas.

While power companies installed large numbers of wind turbines, solar panels and batteries last year to meet rising demand, natural gas use also rose to record highs, while coal use declined only slightly. The net result was that emissions from the power sector increased an estimated 0.2 percent, according to the Rhodium Group.

At the same time, transportation, the nation’s largest source of greenhouse gases, saw an 0.8 percent rise in emissions last year. Gasoline and jet fuel consumption both increased as Americans continued to drive and fly more after the pandemic. Nearly 10 percent of new car sales in 2024 were less-polluting electric vehicles, but those models still make up a small fraction of total cars on the road and have yet to put a major dent in transportation emissions.

On the flip side, emissions from America’s industrial sector — which includes steel, cement and chemicals — fell by 1.8 percent in 2024. Some of that may have been the result of lost output, as two hurricanes and a strike at the nation’s ports disrupted some factory activity in the fall, Mr. King said.

“It’s a reminder that there’s always some bumpiness in emissions,” Mr. King said. “It’s not just a question of how many electric vehicles are on the road or how much solar we’ve installed. A big portion of our economy still relies on fossil fuels.”

One of the most striking findings in this year’s data was that emissions from oil and gas operations dropped roughly 3.7 percent in 2024. Even though the United States produced record amounts of oil and near-record amounts of natural gas last year, many companies appear to have curbed leaks of methane, which is the main ingredient in natural gas and which can seep into the atmosphere and contribute significantly to global warming.

Over the past few years, the Biden administration and several states have adopted new regulations that require oil and gas producers to detect and fix methane leaks. Many companies also have financial incentives to capture methane to sell rather than vent it into the air.

Between 2014 and 2024, U.S. companies appear to have reduced the amount of methane that escaped, per each cubic feet of gas they produced, by 40 percent, according to the Rhodium Group.

Several experts have estimated that greenhouse gases generated in the United States could start dropping sharply in the years ahead if many clean energy policies stay in place, particularly the 2022 Inflation Reduction Act that pumped hundreds of billions of dollars into low-carbon energy technologies such as electric vehicles, wind turbines, solar panels, nuclear reactors, green hydrogen and batteries.

While Mr. Trump has pledged to scrap many of Mr. Biden’s subsidies and tax credits for electric vehicles and low-carbon energy, it remains to be seen whether Congress will agree.

That law has not yet had a major impact on the country’s emissions, said Mr. King, since it takes time for new factories to open and power plants to get built. But, he said, data shows that low-carbon energy and transportation now make up fully 5 percent of total U.S. private investment.

“That’s a leading indicator that things are changing quickly,” he said.

Science

How to protect yourself from the smoke caused by L.A. wildfires

Published

1 day ago

January 9, 2025

Press Room

How to protect yourself from the smoke caused by L.A. wildfires

You don’t have to live close to a wildfire to be affected by its smoke. With severe winds fanning the fires in and around Pacific Palisades, the Pasadena foothills and Simi Valley, huge swaths of the Southland are contending with dangerous air quality.

Wildfire smoke can irritate your eyes, nose, throat and lungs. The soot may contain all kinds of dangerous pollutants, including some that may cause cancer. The tiniest particles in smoke can travel deep into your lungs or even enter your bloodstream.

Conditions like these aren’t good for anyone, but they’re particularly bad for people in vulnerable groups, including children, those with asthma or other respiratory conditions, people with heart disease and those who are pregnant.

Here’s what you should know to keep yourself safe.

Stay indoors

Minimize your exposure to unhealthy air by staying inside and keeping your doors and windows shut.

If you have a central heating and air conditioning system, you can keep your indoor air clean by turning it on and keeping it running. Make sure the fresh-air intake is closed so that you’re not drawing in outdoor air.

Keep your pets inside

They shouldn’t breathe the unhealthy air either.

Check your air filters

Clean filters work better than dirty ones, and high-efficiency filters work better than regular ones. The California Air Resources Board and the South Coast Air Quality Management District recommend filters with a MERV rating of 13 or higher.

You might consider using portable high-efficiency air cleaner in a room where you spend the most time. The U.S. Environmental Protection Agency has information about them here, and CARB has a list of certified cleaning devices here.

Don’t pollute your indoor air

That means no burning candles or incense. If your power is out and you need to see in the dark, you’re much better off with a flashlight or headlamp.

If you’re cold, bundle up. This is not the time to start a cozy fire in the fireplace. Don’t use a gas stove or wood-fired appliances, since these will make your indoor air quality worse, not better, the AQMD says.

The CDC also advises against vacuuming, since it can stir up dust and release fine particles into the air.

Take care when cleaning up

You don’t want your skin to come into contact with wildfire ash. That means you should wear long sleeves, pants, gloves, socks and shoes. The AQMD even wants you to wear goggles.

If you’re sweeping up ash outdoors, get a hose and mist it with water first. That will keep it from flying up in the air as you move it around. Once the ash is wet, sweep it up gently with a broom or mop. Bag it up in a plastic bag and throw it away.

It’s a good idea to wash your vehicles and outdoor toys if they’re covered in ash. Try not to send ashy water into storm drains. Direct the dirty water into ground areas instead, the AQMD advises.

Those with lung or heart problems should avoid clean-up activities.

Discard spoiled food…

If you lost power for a significant length of time, the food in your refrigerator or freezer may be spoiled.

Food kept in a fridge should stay safe for up to four hours if you’ve kept the door closed. If you’ve been without power for longer than that, you’ll need to toss all perishable items, including meat, poultry, fish, eggs, milk and cut fruits and vegetables. Anything with “an unusual smell, color, or texture” should be thrown out as well, according to the U.S. Centers for Disease and Control Prevention.

Refrigerated medicines should be OK unless the power was out for more than a day. Check the label to make sure.

…even if it was in the freezer

Your freezer may be in better shape, especially if it’s well-stocked. Items in a full freezer may be safe for up to 48 hours if it’s been kept shut, and a half-full freezer may be OK for up to 24 hours. (The frozen items help keep each other cold, so the more the better.)

If items have remained below 40 degrees Fahrenheit (4 degrees Celsius) or you can still see ice crystals in them, they may be OK to use or refreeze, according to the federal government’s food safety website.

Ice cream and frozen yogurt should be thrown out if the power goes out for any amount of time. Meat, poultry, seafood, eggs, milk and most other dairy products need to go if they were exposed to temperatures above 40 degrees F for two hours or longer. The same goes for frozen meals, casseroles, soups, stews and cakes, pies and pastries with custard or cheese fillings.

Fruit and fruit juices that have started to thaw can be refrozen unless they’ve started to get moldy, slimy or smell like yeast. Vegetables and vegetable juices should be discarded if they’ve been above 40 degrees F for six hours or more, even if they look and smell fine.

Breakfast items like waffles and bagels can be refrozen, as can breads, rolls, muffins and other baked goods without custard fillings.

Consider alternative shelter

If you’ve done everything you can but your eyes are still watering, you can’t stop coughing, or you just don’t feel well, seek alternative shelter where the air quality is better.

Hold off on vigorous exercise

Doing anything that would cause you to breathe in more deeply is a bad idea right now.

Mask up outdoors

If you need to be outside for an extended time, be sure to wear a high-quality mask. A surgical mask or cloth mask won’t cut it — health authorities agree that you should reach for an N95 or P-100 respirator with a tight seal.

Are young children at greater risk of wildfire smoke?

Very young children are especially vulnerable to the effects of wildfire smoke because their lungs are still rapidly developing. And because they breathe much faster than adults, they are taking in more toxic particulate matter relative to their tiny bodies, which can trigger inflammation, coughing and wheezing.

Any kind of air pollution can be dangerous to young children, but wildfire smoke is about 10 times as toxic for children compared to air pollution from burning fossil fuels, said Dr. Lisa Patel, clinical associate professor of pediatrics at Stanford Children’s Health. Young children with preexisting respiratory problems like asthma are at even greater risk.

Patel advises parents to keep their young children indoors as much as possible, create a safe room in their home with an air purifier, and try to avoid using gas stoves to avoid polluting the indoor air.

Children over the age of 2 should also wear a well-fitting KN95 mask if they will be outdoors for a long period of time. Infants and toddlers younger than that don’t need to mask up because it can be a suffocation risk, Patel said.

What are the risks for pregnant people?

Pregnant people should also take extra precautions around wildfire smoke, which can cross the placenta and affect a developing fetus. Studies have found that exposure to wildfire smoke during pregnancy can increase the risk of premature birth and low birth weight. Researchers have also linked the toxic chemicals in smoke with maternal health complications including hypertension and preeclampsia.

What about other high-risk populations?

Certain chronic diseases including asthma, chronic obstructive pulmonary disease or other respiratory conditions can also make you particularly vulnerable to wildfire smoke. People with heart disease, diabetes and chronic kidney disease should take extra care to breathe clean air, the CDC says. The tiny particles in wildfire smoke can aggravate existing health problems, and may make heart attacks or strokes more likely, CARB warns.

Get ready for the next emergency

Living in Southern California means another wildfire is coming sooner or later. To prepare for the bad air, you can:

Stock up on disposable respirators, like N95 or P-100s.
Have clean filters ready for your A/C system and change them out when things get smoky.
Know how to check the air quality where you live and work. The AQMD has an interactive map that’s updated hourly. Just type in an address and it will zoom in on the location. You can also sign up to get air quality alerts by email or on your smartphone.
Know where your fire extinguisher is and keep it handy.
If you have a heart or lung condition, keep at least five days’ worth of medication on hand.

Times staff writer Karen Garcia contributed to this report.