What do you think about when you hear the words “microplastic pollution?” Your mind may immediately go to imagery of colorful fragmented plastics broken off from bottles, buckets and other items we use in our everyday lives. Or, perhaps, you imagine a pile of microplastic fibers—the tiny, squiggly, spaghetti-shaped plastics that shed from our synthetic clothing. You may be surprised to hear there is another major source of microplastic pollution that’s hiding in plain sight, quite literally under our feet, that might change how you think about microplastics: tire particles.

We all know tires wear down over time—that’s why we have to replace them on our cars roughly every 60,000 miles or so. Every time a vehicle accelerates, brakes or simply drives down the road, the friction between its tires and the pavement creates tiny fragments of rubber, known as tire wear particles.

Tires are made from a complex mix of natural and synthetic rubber along with a range of additives, fillers and chemical compounds—some of which, like the preservative 6PPD, have been shown to be highly toxic to coho salmon when they break down into derivative product 6PPD-Q in the environment—even in tiny concentrations.

Some studies have shown that a single vehicle’s tires can emit more than two trillion particles per mile driven—and that the average person generates nearly two pounds of tire particles per year! Once these particles are shed from tires, they don’t just disappear. Some are small and light enough to become airborne, drifting away from roadways as dust. Others settle on road surfaces, where they accumulate until the next heavy rain washes them into storm drains and from there, into streams, rivers and eventually the ocean.

That’s why tire wear particles are now considered one of the top sources of microplastics to the environment. In fact, until recent developments in analytical methods, scientists weren’t reliably able to detect tire wear particles in microplastic counts—thus, these pesky microplastics may have been evading our detection for years.

Why green infrastructure may be one of our best near-term solutions

Unlike some sources of plastic pollution, we can’t simply stop driving overnight. Reformulating tire rubber to be less toxic or shed less material, while promising, will take time to develop, test and scale across the global vehicle fleet. So, what can we do about tire wear particle pollution right now?

This is where green infrastructure comes in. Green infrastructure refers to engineered natural systems (things like bioswales, rain gardens, roadside buffers and permeable pavement) that are designed to slow down, filter and treat stormwater before it reaches rivers, lakes and coastlines. Instead of routing runoff directly into storm drains and out to sea, green infrastructure gives contaminated water a chance to percolate through soil, plants and other natural filtration media, which helps trap microplastics, including tire wear particles, preventing them moving further downstream.

Early research on green infrastructure has been promising, showing that these systems are quite effective at capturing microplastics and other contaminants carried in road runoff. But there’s a critical piece we still don’t fully understand: What would it take to scale up green infrastructure across an entire city, and how much of a dent would that actually make in long-term tire wear particle pollution?

Our research on green infrastructure capture of tire wear particles

Funded by the Tire Industry Project, our plastics science and policy teams at Ocean Conservancy have partnered with the University of Toronto on a new study evaluating the costs and benefits of scaling up green infrastructure at the city level specifically to capture tire wear particles.

If you happen to be driving on the roadways of Portland, Oregon, you may spot our scientists crouched over, precariously scooping dirt with spoons from a sample area on the roadside. Don’t be alarmed—that’s just us doing science! Feel free to give us a wave.

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Ocean Conservancy is currently working to:

• Quantify the scale of pollution: Collect road dust samples from 30 cities globally to measure both total microplastic and tire wear particle concentrations and determine how different variables (population density, road size, rainfall) might influence those values.
• Assess feasibility: Determine what it would take realistically—logistically, financially and spatially—to scale up green infrastructure across an entire city.
• Model positive impacts: Estimate how much city-scale green infrastructure could reduce tire wear particle pollution entering aquatic ecosystems.
• Compare across cities: Understand how well these solutions might translate across different urban contexts, focusing on Portland, Oregon; Toronto, Canada; and London, England as case-study cities.
• Make our findings accessible: Produce a public-facing toolkit to help city planners, engineers and advocates guide real-world implementation of infrastructure that captures tire-wire particles. 

By pairing rigorous science with practical guidance, we hope to help cities move from asking “Could this work?” to confidently building solutions that we know can be effective.

How can I help?

Tire wear particle pollution can feel like an overwhelming problem. After all, it’s tied to transportation, which most of us rely on every day. But that’s exactly why research like this matters: It gives us a real, near-term path forward that doesn’t require waiting for the entire global transportation system to change first.

You can help by staying engaged with Ocean Conservancy as we continue to dig into solutions for the plastic pollution crisis—one roadway, one storm drain and one city at a time. Together, we can keep working toward a world and ocean free of plastic pollution, forever and for everyone.

The post What are Tire Wear Particles? appeared first on Ocean Conservancy.

What are Tire Wear Particles?

A small jellyfish-like animal recently reported from Vejle Fjord has attracted attention. Clear photographs suggest that it belongs to the genus Gonionemus and may possibly be the clinging jellyfish, Gonionemus vertens (Picture courtesy to Jonas Bøgelund Poulsen)

Unlike the large jellyfish commonly encountered along Danish coasts, Gonionemus vertens is a small hydromedusa, usually only around 1.5–2.5 centimetres across. Its transparent bell reveals four coloured reproductive structures arranged like a cross. Numerous fine tentacles surround the bell, often appearing bent or angled. Small adhesive pads near the ends of the tentacles allow the animal to attach itself to eelgrass, seaweed and other submerged vegetation.

This unusual behaviour explains its English name: the clinging jellyfish. During the day, it often remains attached to vegetation rather than drifting freely with the current. At night, it becomes more active and swims into the water column to feed on zooplankton and small crustaceans. Consequently, it can easily remain unnoticed even in places where it is already established. Another reason the species can be difficult to detect is its life cycle. The visible medusa is only one stage. For much of its life, the animal may persist as a minute polyp attached to a hard surface, shell or vegetation. These inconspicuous polyps can reproduce asexually and later release new medusae when environmental conditions become favourable.

Gonionemus vertens is generally considered native to the northern Pacific but has been introduced into several parts of Europe and the Atlantic. Transport on ship hulls, in ballast water or with movements of oysters and other marine organisms has been suggested as possible pathways, although the pathway responsible for any particular occurrence is rarely known with certainty.

Despite its delicate appearance, the animal should not be touched. Some populations possess powerful stinging cells and have caused intense pain, swelling, muscle cramps and, in rare cases, serious allergic reactions. Sting severity differs considerably among regions, which is one reason researchers suspect that animals currently grouped under the name G. vertens may represent a complex of closely related forms.

The Vejle Fjord observation is therefore scientifically interesting, but it should not yet be presented as a confirmed record of G. vertens. Anyone encountering a similar animal should photograph it without handling it and record the date, exact location, approximate size, number observed and surrounding habitat. Observations can be submitted to Denmark’s national species portal, Arter, where they can be evaluated and contribute to tracking changes in Danish marine biodiversity. Please use either my App: GoJelly JellySpotter or reprot to the Arter.dk: Gonionemus taxon page and Danish species-reporting portal.

References:

Edwards, C. (1977). A study in erratic distribution: The occurrence of the medusa Gonionemus in relation to the distribution of oysters. Advances in Marine Biology, 14, 251–284. DOI: 10.1016/S0065-2881(08)60448-4.
Govindarajan, A. F., Källström, B., Selander, E., Östman, C., & Dahlgren, T. G. (2019). The highly toxic and cryptogenic clinging jellyfish Gonionemus sp. (Hydrozoa, Limnomedusae) on the Swedish west coast. PeerJ, 7, e6883. DOI: 10.7717/peerj.6883.

A tiny but remarkable visitor in Vejle Fjord-Denmark?

The JOIDES Resolution (JR) was a renowned, international, scientific research ship. It was home to over 190 expeditions, each sailing for 60 days at a time without docking. Scientists and crew members from all over the world met to discover Earth’s secrets through studying ocean cores. Every two months the JR would get a new crew, sailing to an entirely new place. This once in a lifetime experience forms special and unforgettable social connections.

Since working on the JR I’ve kept those connections strong with snail mail. I have always been an avid penpal, so meeting new friends means new addresses to send my letters and postcards to. Experiences like sailing on the JOIDES Resolution or participating in programs like OCEAN CORE Academy is one of the ways I’ve met people from all over the world.

Now that the JR is retired, there is no more scientific research drilling being done through the International Ocean Discovery Program (IODP). But, there is still plenty to learn from ocean cores, and plenty of people to meet through programs like OCEAN CORE Academy (OCA). OCA is an annual summer opportunity from the U.S. Scientific Support Program (USSSP) that hosts undergraduates interested in geoscience related careers. Students can apply to this program for a chance to research and study data recovered from cores originally brought up by the JR, now located at the Gulf Coast Repository (GCR) in College Station, Texas. Students also practice forms of science communication with the guide of mentors. As a science communicator and fan of snail mail, I ran a craft night teaching students how to make and send science-themed postcards.

Fig. 1) students using watercolor to paint onto 4 by 6 inch board paper, a photo of a thin section slide is in the background. Photo by Dr. Leah Joseph.

For this project, we based the cover image of the postcards off of rock thin section slides. These slides are a slice of a hard rock or mineral that’s been glued to a microscope slide, sanded to 0.03 millimeter thickness, and polished. Thin section slides are used to identify grain size, shape, color, and other physical properties. This helps scientists understand the textural relationships between the rocks and determine the origin or evolution of the parent rock. Thin sections can also be helpful for identifying minerals using cross polarized light (XPL). XPL reduces light reflection and glare, commonly used for sunglasses and professional photography, but in a polarizing microscope, XPL is used to create a dark field causing certain minerals to appear brighter and more visible. Different colors are associated with different minerals, and as the stage of the microscope rotates, light passes through the slide in unique ways aiding scientists with identification. Identifying minerals can help scientists in understanding more about where the rocks came from and how old they are. These thin sections are not only informative, but are incredibly beautiful, making unique and stunning postcard covers.

Fig. 2) Examples of thin section slides under a XPL microscope, bronzitite (left) and gabbro (right). Sourced from here.

After the OCA students finished their paintings, my home-made “post card” stamps go on the back, a stamp gets added, and they’re ready to be mailed out. Although most OCA participants this year were U.S. based, they came from all over, ranging from Staten Island to San Francisco to Arizona to Connecticut. In addition to one mentor from New Zealand!  For many of these students this was their first time traveling on their own, and their first time forming long-distance connections. With these scientific postcards, OCA students can stay connected by reminding each other of the science they learned together. My experience on the JR taught me great things about geological research, but it also gave me life long connections that I cherish. Although the JR is gone, its legacy lives on in our memories and the ways we stay connected with friends. I’m grateful to know that even without an international ship, I’m still able to add friends to my address book.

Fig. 3) Examples of participant made postcards

Written by Kellan Moss

New Friends, New Addresses