Car tires, a bigger threat than polyester blouses

I sound like a broken record, but the culprit is almost always cars.

Cars are a death cult. They cause most of our air and water pollution, green house gas emissions, and consume most of the land in the cities with their voracious appetite for parking spaces and road space.

In Heavy Metal in LA, I explained that the biggest source of heavy metal contamination in Los Angeles waters is cars.  Now we learn that cars are the biggest source of microplastics in the San Francisco Bay Area. The biggest likely source of microplastics in California coastal waters? Our car tires

Cars driving over Golden Gate Bridge photo from LA Times

Sewists can quit obsessing over polyester use.  The much bigger problem is all of our cars.

Rainfall washes more than 7 trillion pieces of microplastics, much of it tire particles left behind on streets, into San Francisco Bay each year — an amount 300 times greater than what comes from microfibers washing off polyester clothes, microbeads from beauty products and the many other plastics washing down our sinks and sewers.

I downloaded and read the SFEI report, Understanding Microplastic Levels, Pathways, and Transport in the San Francisco Bay Region.

The methodology section starts on page 30. They collected and sieved microparticles from storm runoff, sewage treatment plants and sediment.  Then they sieved again and again to separate out particles by size.

Particles were further sorted by color, shape and appearance.  Finally, the material composition of 7% of the microparticles were determined by Raman and FTIR spectroscopy.  Not all microparticles were plastics.  E.g. some were glass or organic materials.

Particles found in this study

The most astonishing finding was the abundance of black, rubbery fragments.

A total of 171 microparticles were classified as unknown potentially rubber, which represents 84% of black, rubbery fragments that were analyzed by spectroscopy, or 44% of all fragments analyzed (21% of all particles analyzed). Only one site, Rodeo Creek (a mostly rural site), had zero rubbery fragments.

The discussion explains why they are sure that the black rubbery fragments are tire wear.  They also summarize findings about the prevalence and abundance of tire wear in the environment by other researchers starting on page 55.

I suspect that the results would be the same if the expensive and laborious study was repeated in Los Angeles.

Don't feel bad if you wear polyester blouses or fleece jackets instead of exclusively natural fibers.  Just wash them in the coolest water that still gets them clean, air-dry them, and walk/bike/transit instead of driving.

Those are choices that really matter.

Related Posts:

• How 'Green' is your T-shirt?
• Heavy Metal in LA
• Wear polyester if you like