6ppd

Car tires in your salad

June 26, 2024 By EarthWise Leave a Comment

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

December 13, 2023 By EarthWise Leave a Comment

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

Pollution From Tires | Earth Wise

October 16, 2023 By EarthWise Leave a Comment

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

What’s Been Killing Salmon? | Earth Wise

January 5, 2021 By EarthWise Leave a Comment

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.