Tiny tire particles inhibit growth of organisms in freshwater, coastal estuaries, studies find

Date:
March 1, 2022
Source:
Oregon State University
Summary:
Small particles from tires inhibited the growth and caused adverse
behavioral changes in organisms found in freshwater and coastal
estuary ecosystems, two new research papers found.



FULL STORY ========================================================================== Small particles from tires inhibited the growth and caused adverse
behavioral changes in organisms found in freshwater and coastal estuary ecosystems, two new research papers from Oregon State University
scientists found.


==========================================================================
The findings are part of a continued effort by scientists to unravel
the impacts of microplastics and nanoplastics on aquatic ecosystems and
aquatic organisms. Tire particles are one of the most common microplastic
types in aquatic ecosystems.

Harper, Brander and several other graduate students and a post-doctoral scholars in their labs, including Brittany Cunningham, Samreen Siddiqui, recently published two papers on the tire particle research in Chemosphere
and the Journal of Hazardous Materials.

"The focus on microplastics and now nanoplastics is still relatively
new," said Stacey Harper, an Oregon State professor who studies the environmental health and safety impacts of nanomaterials and led the
research on tire particles in freshwater organisms. "We're now at
the point of making policy decisions that we don't have the science
for. That's why we are scrambling to supply that science." California is
at the forefront of this issue, with a statewide microplastics strategy
adopted last week. Similar efforts at the federal level and potentially
among other states are anticipated, said Susanne Brander, an assistant professor and ecotoxicologist at Oregon State who led the coastal study
on tire particles and was also co-chair for one of the several science
advisory teams that helped develop the California strategy.

Tire particles are composed of materials including synthetic rubber,
filling agents, oils and other additives. The particles themselves and chemicals they leach, known as leachate, may have detrimental effects
on aquatic organisms they come in contact with, the researchers note.



==========================================================================
The researchers cite studies that show during the lifetime of
an automobile tire about 30% of its tread erodes and enters the
environment. They also cite a recent study that estimated more than 1.5
million metric tons of tire wear particles flow into the environment
each year in the United States.

"I feel in particular with tire particles that everyone is measuring how
much is out there, but very few groups are measuring what impact they are having," Brander said. "That's really the gap we were trying to patch
up here." To do that, the Oregon State scientists exposed two model
organisms in both the freshwater and estuary ecosystems to different concentrations of micro and nano tire particles and to leachate created
by the breakdown of the tire particles.

Microparticles are fragments less than 5 millimeters (0.20 inches)
in length.

Nanoparticles are so small that are not visible to the naked eye or
under a simple microscope.

In the estuary ecosystem paper, led by post-doctoral scholar Samreen
Siddiqui, the model organisms were Inland Silverside and mysid
shrimp. Findings by the researchers included:
* Both organisms, after being exposed, had significantly altered
swimming
behaviors at concentrations detected in the environment, such
as increased freezing, changes in positioning and total distance
moved, which the researchers note could lead to an increased risk of
predation and challenges for the organisms to find food in the wild.

* Both organisms had reduced growth depending on the level of
exposure to
micro tire particles, fish exposed to nano tire particles also
had reduced growth.

* Leachates affected behavior but did not impact growth in either
organism.

These findings led the researchers to conclude that even at current environmental levels of tire-related pollution, which are expected to
increase, aquatic ecosystems may be experiencing negative impacts.



==========================================================================
In the freshwater ecosystem paper, led by graduare student Brittany
Cunningham, embryonic zebrafish and the crustacean Daphnia magna were
the model organisms.

Among the findings:
* Both organisms experienced mortality and developmental abnormalities
due
to tire particle and leachate exposures.

* Tire particle leachate was the main driver of toxicity for both
organisms.

* Exposure to nano tire particles enhanced toxicity in comparison to
leachate alone.

These findings led the researchers to conclude that while toxicity from
tire particles was observed in both organisms, overall sensitivity to
tire particles differed. They believe that it is important to understand
these differences to identify levels at which these pollutants become
toxic. This knowledge, they note, is crucial for the creation of risk assessments, which inform policy decisions.

The researchers also mentioned several ways to limit tire particles from entering the environment. These include installing rain gardens on the
sides of roads to capture tire particles, installing particle capture
devices on cars, developing tires that last longer and investing in green infrastructure, such as public transit, that allows people to drive less.

The research is supported by a National Science Foundation Growing
Convergence Research Big Idea grant. The grant supports the Oregon
State-based Pacific Northwest Consortium of Plastics, which Harper and
Brander co-lead.

Harper and Brander are based in the Oregon State College of Agricultural Sciences. Other co-authors of the papers include Bryan Harper, Sarah
Hutton, John Dickens and Emily Pedersen.

========================================================================== Story Source: Materials provided by Oregon_State_University. Original
written by Sean Nealon.

Note: Content may be edited for style and length.


========================================================================== Journal References:
1. S. Siddiqui, J.M. Dickens, B.E. Cunningham, S.J. Hutton,
E.I. Pedersen,
B. Harper, S. Harper, S.M. Brander. Internalization, reduced growth,
and behavioral effects following exposure to micro and nano tire
particles in two estuarine indicator species. Chemosphere, 2022;
133934 DOI: 10.1016/ j.chemosphere.2022.133934
2. Brittany Cunningham, Bryan Harper, Susanne Brander, Stacey Harper.

Toxicity of micro and nano tire particles and leachate for model
freshwater organisms. Journal of Hazardous Materials, 2022; 429:
128319 DOI: 10.1016/j.jhazmat.2022.128319 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220301093650.htm

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