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Microplastics and birds

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Microplastics are tiny plastic particles, less than 5 millimeters in size, that come from the breakdown of larger plastics, synthetic fibers, microbeads, and tire wear.  Microplastics are found in oceans, rivers, soil, and even the air we breathe. These particles can take hundreds of years to degrade, spreading across ecosystems and accumulating in unexpected places, such as deep-sea sediments and Arctic sea ice.

According to a new study by researchers from the University of Texas at Arlington, microscopic plastic pollutants drifting through the air are lodging in the lungs of birds.  These findings raise  significant concerns about the impact on their respiratory health, but also raise alarms about potential risks to human health.

Birds were chosen for the study because they are found in almost every corner of the world and often share environments with humans. 

In the study, the research team examined 56 different wild birds from 51 distinct species, all sampled from the Tianfu airport in western China.  The researchers found high concentrations of microplastics in bird lungs, with an average of 221 particles per species.  The most common types identified were chlorinated polyethylene, which is used for insulating pipes and wires, and butadiene rubber, which is a synthetic material in tires.

Although there is no established “safe” level of plastic particles in lung tissue, high levels of microplastics have been linked to serious health risks, including heart disease, cancer, respiratory issues, and fertility problems.

The study highlights an urgent need to tackle plastic pollution in the environment because of its far-reaching impact on ecosystems and human health.  

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Birds breathe in dangerous plastics—and so do we

Photo, posted January 28, 2017, courtesy of Pete Richman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Car tires in your salad

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There seems to be no end to the types of pollution we have introduced into the environment.  One that has only recently started to gain attention is pollution caused by vehicle tires. 

Through normal wear and tear, as vehicles drive along roadways, their tires cast off countless bits of rubber.  These particles can linger in the atmosphere or can be washed down sewage drains and into waterways.  In the water, these particles leach compounds that are toxic to wildlife.

Tires contain various chemical additives that prevent them from cracking and degrading along with various metals and other materials added to rubber and artificial rubber.  Some of these additives are acutely toxic or even carcinogenic.

A recent study by researchers at the University of Vienna tested leafy vegetables that were grown in Switzerland, Spain, and Italy, and were sold in Swiss supermarkets.  The study also tested vegetables harvested directly from Israeli farmlands.

Tire ingredients were found in 11 out of 15 samples gathered from Swiss supermarkets and 9 out of 13 samples collected from Israeli fields.  Among these are 6PPD, a tire additive that has been identified as the cause of the extensive deaths of coho salmon on the US West Coast.

The researchers say that farmers may be introducing tire additives by irrigating crops with treated wastewater or by using sewage sludge as fertilizer.  Airborne tire particles may also be settling on farm soil.

The concentration of tire particles found in the leafy vegetables are relatively low, but it is troubling that we are eating dangerous chemicals used to improve the quality of tires.

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Leafy Vegetables Found to Contain Tire Additives

Photo, posted October 14, 2014, courtesy of Green Mountain Girls Farm via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Action on the toxic chemical from tires

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Since the 1990s, populations of coho salmon in streams and urban creeks up and down the West Coast have been dying in large numbers.  Scientists at the University of Washington began studying the mysterious deaths and it took years to figure out what was going on.  They analyzed water samples from urban creeks and found that chemicals from vehicle tires were present.  By soaking tires in water, they found that more than 2,000 chemicals were present.  It took three years to narrow down the suspect list to one chemical:  a toxin called 6PPD-quinone, which is produced when the common tire preservative 6PPD mixes with oxygen.  It is that chemical that was responsible for the salmon die-off.

6PPD-quinone is toxic enough to quickly kill some fish.  Studies showed that concentrations of the chemical in stormwater were found to be lethal for coho salmon following exposures lasting only a few hours.

Despite the discovery, the tire industry has continued to use the chemical in its products.  The industry says 6PPD is an antioxidant and antiozonant that helps prevent degradation and cracking of tires in the environment and is essential for the performance and safety of vehicles.

Last year, California regulators directed the tire industry to seek out substitutes for 6PPD.  The U.S. Tire Manufacturers Association pledged to investigate possible safer alternatives to the chemical.

In November, spurred by a petition by West Coast tribes whose lifeways depend on coho salmon, the EPA said it will study the impact of 6PPD with an eye to potentially banning its use. 

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After Salmon Deaths, EPA Takes Aim at Toxic Chemical Issuing from Car Tires

Photo, posted May 31, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastics In The Air | Earth Wise

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Plastic pollution is a big deal.  There are plastics clogging up landfills and waterways and accumulating in the oceans, choking turtles and seabirds.  Annual production of plastics has grown from 2 million tons a year in 1950 to more than 450 million tons today.

As if plastic problems weren’t already big enough, it is becoming increasingly clear that there are growing amounts of microplastic particles in the air. Bits of plastic are lofted into the sky from seafoam bubbles and from spinning tires on highways.  The particles are so light that they can travel for thousands of miles, far from where they originate.

Studies in recent years documented the presence of plastic particles even in places like the Pyrenees in Europe and in federally protected areas of the US.  Other studies have measured the quantity of plastic in the air of various locations and have looked at the origins of the particles.

In the western US, over 80% of microplastics came from roads where vehicles kick up particles from tires and brakes.   In remote areas of the Pacific, there is less than a single particle of plastic per cubic meter of air.  In cities like London and Beijing, on the other hand, there can be several thousand particles per cubic meter.

Microplastics can act as airborne aerosols, like dust, salt, soot, volcanic ash, and other particles.  Aerosols play an important role in the formation of clouds and in temperature regulation on the earth.  At low concentrations, such as exist in most places, microplastic aerosols don’t have much of an effect.  But there are more in the atmosphere all the time and, at this point, scientists don’t really know what effect they will have.

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Microplastics Are Filling the Skies. Will They Affect the Climate?

Photo, posted August 28, 2014, courtesy of Alan Levine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pollution From Tires | Earth Wise

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A few years ago, researchers investigating massive deaths of coho salmon in West Coast streams discovered that the water contained particles from vehicle tires.  The cause of the fish mortality turned out to be a chemical called 6PPD that is added to tires to prevent cracking and degradation.  The mystery was solved, but so far, the chemical continues to be used by all major tire manufacturers and is found on roads and in waterways around the world.

Worse still, the acute toxicity of 6PPD and the chemicals that it transforms into when exposed to ground-level ozone is only the tip of the tire pollution iceberg.  Tire rubber contains more than 400 chemicals and compounds, many of which are carcinogenic. 

About 2 billion tires are sold across the globe each year and that number is expected to reach 3.4 billion by 2030.  Tires are made from about 20% natural rubber and 24% synthetic rubber, which requires about 4 gallons of petroleum per tire.  Hundreds of other ingredients – including steel, fillers, heavy metals like copper, cadmium, lead, and zinc – make up the rest.

Tire wear particles are emitted continually as vehicles travel.  They range in size from visible pieces of rubber or plastic to microparticles.  Research has shown that a car’s four tires collectively emit half a trillion ultrafine particles per mile driven.  These particles are small enough to be breathed into the lungs and can travel throughout the body and even cross the blood-brain barrier.  Particle pollution from tires exceeds that from tailpipes.

Tire pollution is a huge problem that is just starting to receive the attention it deserves.

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Road Hazard: Evidence Mounts on Toxic Pollution from Tires

Photo, posted June 22, 2018, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar Bears and Tires | Earth Wise

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There is lots of interest in traction.  People want to find better ways to move across wet and frozen surfaces safely.   This applies to both the shoes on our feet and the tires on our cars. 

Researchers at the University of Akron along with colleagues at Syracuse University and at Bridgestone, the tire company, have been studying how many arctic animals can walk and run across the ice without slipping and falling.  Their research focused on the paws of polar bears.

Previous studies discovered that polar bears have papillae – little bumps on the pads of their feet – that provide improved traction on snow.  The new research also looked at the paws of other species of bear – brown bears and black bears – and found that these others also have papillae on their paw pads, but that those of polar bears are as much as 50% taller.  These taller bumps give the pads a 30-50% increase in frictional shear stress.

The research may lead to various applications. For example, snow tires typically have deeper treads, but the polar bear study may lead to some new designs that would improve traction.  People who do high-altitude climbing are interested in the research as are companies that deliver goods in bad weather.  Anyone who has to be out and about in bad weather would like to get a better grip.

There are various other animals with traction-improving adaptations that are probably worth studying.  These include dogs, wolves, foxes, and mountain goats.  The same researchers at Akron have also studied other animals with unique abilities to deal with challenging surfaces including geckos, spiders, and mussels.  The natural world is filled with examples of creatures who can easily function in environments that we humans find very challenging.

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UA researchers’ focus on tire traction leads to investigation of polar bear paws

Photo, posted March 2, 2008, courtesy of Sam Weng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Atmospheric Plastic Polluting The Ocean | Earth Wise

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According to estimates, by 2040 there will likely be nearly 90 million tons of plastic pollution entering the environment each year.  Particles of plastic have been found in virtually all parts of our planet including the land, the water, and even the air.  Tiny plastic particles have been found in the Arctic, the Antarctic, and at the tops of the highest mountains.

A new study has shown that winds can carry plastic particles over great distances and in fact can bring them from their point of origin to the most remote places in a matter of days.   As a result, micro- and nanoplastics can penetrate the most remote and otherwise largely untouched regions of the planet

How does plastic get into the atmosphere?  Particles produced by tires and brakes in road traffic or ones in the exhaust gases from industrial processes rise into the atmosphere, where they are transported by winds.  There is also evidence that a substantial number of these particles are transported by the marine environment.  Microplastic from the coastal zone finds its way into the ocean through beach sand.  A combination of sea spray, wind, and waves forms air bubbles in the water containing microplastic.  When the bubbles burst, the particles find their way into the atmosphere.

Understanding the interactions between the atmosphere and ocean is important because the atmosphere turns out to be a major mechanism in depositing substantial amounts of plastic into a broad range of ecosystems.

The impact of plastic particles on ecosystems is not well understood.  Neither is the effect of plastic particles in the air upon human health.  In a recent British study, microplastic was detected in the lungs of 11 out of 13 living human beings.

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Micro- and nanoplastic from the atmosphere is polluting the ocean

Photo, posted April 25, 2016, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Octopuses And Litter | Earth Wise

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Octopuses are remarkably intelligent animals.  They have a larger brain for their body size than all other animals apart from birds and mammals.  They exhibit high-order cognitive behaviors including tool use and problem solving.  Some captive octopuses learned to shoot jets of water at aquarium light switches to turn them off.  Others have learned to unscrew jar lids to get at food.

A recent analysis of underwater imaging has shown that octopuses are increasingly using discarded bottles, cans, and other human-generated litter as shelter or as a place to lay eggs.

The research documented 24 species of octopus sheltering inside glass bottles, cans, and even an old battery.  Some buried themselves under a mixture of bottle caps and seashells.  Others even carried plastic items around while walking on just two tentacles to disguise themselves from predators.

The octopuses showed a preference for unbroken items and for darker or opaque containers.  Normally, octopuses make use of natural shelters such as seashells.  Whether they are making use of litter simply because there is so much of it around or because there is an increasing lack of natural items is not clear.

As with all other aspects of the growing problem of litter in the oceans, this new trend is not a good one.  Sheltering or laying eggs inside discarded tires, batteries, or plastic items has the potential to expose octopuses to heavy metals and other harmful chemicals.

Octopuses are intelligent and resourceful animals, and they will use whatever they have at their disposal to continue sheltering or moving around with protection from potential predators.

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Octopuses Have Learned to Make Use of Ocean Litter, Study Finds

Photo, posted May 13, 2014, courtesy of Elias Levy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s Been Killing Salmon? | Earth Wise

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For decades, there have been mysterious deaths of Coho salmon.  The salmon return from the Pacific Ocean each year to spawn along the West Coast.   They can be found from Alaska all the way down into California.  After heavy rain events each fall, fish have been turning up dead in huge numbers before they spawn.  Normally, less than 1% of adult Coho die before spawning. In these mass death events, anywhere from 40% to 90% of fish can perish in affected streams.  The mysterious phenomenon has been the subject of intense research for years.

Recently, scientists announced that they may have solved the mystery.  There is a chemical antioxidant known as 6PPD that is used in the manufacture of tires around the world to make them last longer.  As tire treads break down over time, they leave behind bits of microplastics on roads.  The 6PPD in the plastic bits reacts with ozone to become another chemical:  a previously unreported substance called 6PPD-quinone.

That chemical turns out to be toxic to Coho salmon.  Researchers have found the presence of 6PPD-quinone in roadway water runoff samples taken from across the West Coast.  Based on these observations, they believe it is likely that exposure to this chemical is the main cause of the Coho salmon population decline.

Coho salmon are a favorite of sport fishermen and have great cultural significance to many Native American tribes on the West Coast.  The central California Coho population is classified as endangered and three other Coho populations are listed as threatened.

Tire industry representatives call the study results “preliminary” but say the industry is deeply committed to protecting the environment.  A safe chemical substitute for 6PPD is clearly needed.

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Salmon have been dying mysteriously on the West Coast for years. Scientists think a chemical in tires may be responsible

Photo, posted November 17, 2011, courtesy of Lynn Ketchum/Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tires From Trees

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Car tires are generally considered environmentally unfriendly because they are predominantly made from fossil fuels.  Natural rubber is generally not used anymore; most tires are made from isoprene, which is chemically very like rubber but is produced by thermally breaking apart molecules in petroleum in a process called cracking.  The isoprene is separated out and purified and then reacted to form the artificial rubber that is the major component in car tires.  The tires eventually end up discarded in giant piles that represent one of our biggest waste disposal problems.

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