But might crops absorb plastics in the soil, like they do water and nutrients, and incorporate them in these edible bits? To test this, Wash- ington State University soil scientist Markus Flury and his colleagues at the Pacific Northwest National Laboratory recruited wheat and a com- mon plant used in crop science, thale cress, as botanical guinea pigs. These species represent the two types of root strategies in the plant king- dom: wheat uses a fibrous root system, in which lots of filaments spread
through the soil like a net, while thale cress uses a taproot system, in which smaller offshoots branch off from a thick main root—think of a carrot growing underground. Flury and his team grew seeds from each species in agar—a sort of scientific Jell-O—laced with fluorescent mi- croplastic and nanoplastic beads.102
When Flury looked at the plants under a confocal microscope, which shines lasers that make the fluorescent dye in the plastics glow, he found particles had attached to the roots but hadn’t penetrated them. So this is worrisome in that plastics might be accumulating around the roots we eat—carrots, sweet potatoes, radishes—but it’s good news in that nei- ther a fibrous nor taproot system seemed to uptake plastic into the plant itself, unlike how crops readily soak up nutrients like nitrogen and iron. “The plant has probably an incentive to take up an iron particle, whereas a plastic particle will not be used by the plant,” says Flury.
This contradicts previous lab studies on wheat and other crops, like beans and onions and lettuce, showing that roots do take up plastics.103 Over at ETH Zürich, analytical chemist Denise Mitrano took a differ- ent tack, tagging nanoplastics not with fluorescence but with the rare metal palladium. And instead of growing wheat in agar, she grew it hy- droponically, exposing the growing plants to the “doped” particles. She could then track the nanoplastics as the wheat plants took them up into their roots and shoots. “We didn’t let the wheat go to grains, so we don’t know if the nanoplastic would eventually get into the food source, but it did go up further into the plant,” says Mitrano. However, she didn’t see any big changes in the physiology of the plants, like growth rate or chlo- rophyl production. “But we did see that it changed the root structure a bit and the cellular structure in the root, which would indicate that the plant was still under stress.”
I live in San Francisco, which draws from Yosemite’s Hetch Hetchy Reservoir, a source of water so pure, the state doesn’t require it to be filtered before it comes out of my faucet. “No one has tested San Francisco tap water for microplastics,” Coffin says. “But we believe that of all the places in California that we’re going to find it, we’re going to find it in highest quantities in San Francisco’s, because there’s no filtration at all.”
if you’re drinking treated water, count your blessings. A third of humanity lacks access to a safe supply of drinking water, exposing these people to all kinds of diseases and potentially more microplastic.121 If you’re drawing your water from a plastic-polluted lake or river, you may be drinking a sort of plasticine soup—as bottles and bags float around baking in the sun, they’re jettisoning little bits of themselves. Add to this the runoff from cities, bits of car tires and cigarette butts and fibers from our clothes, and a water source grows lousy with petroparticles. Indeed, a survey of 67 European lakes found the concentrations of microfibers to be four times greater in waters with high human activity than in more remote systems.122 The densely populated Great Lakes are packed with particles: one study found over 12,000 microplastics and other anthropogenic particles in just 212 fish pulled from Lake Ontario— one unlucky animal had 915 pieces in its gut
n 2015, researchers sampled the living rooms of two apartments in Paris, each home to two adults and a child, as well as a university office where three people worked.31 They only sampled air when people were present in the rooms, both at a height of about four feet to gather what the subjects are breathing, and a half inch off the ground to determine the deposition rate of dust. The researchers also took samples from vac- uum cleaner bags the occupants had used in the two apartments.
In one apartment, they counted up to 14 fibers floating in a cubic yard of air, 12 in the other, and 45 in the office. Based on the number of particles they caught near the floor, the researchers calculated that up to a thousand fibers are deposited per square foot each day, which matched with the number of fibers they found in the vacuum bag
[well at least they still don’t make up the majority of PM2.5 pollution, and that is declining, and that reason alone is why I don’t freak out that much yet…]
I’m noticing estimates are on the severely low end… But you also have to ask questions like "total consuption of dirt/wood particles [or rocks] because some of these also get lodged in the body over time and THEN compare this to microplastic dose…
“BPA hardens plastics and phlatates soften them”
In one study, 11 patients in Malaysia who’d undergone colectomies—the removal of portions of the colon—provided tissue samples.100 Nine of the patients had colon cancer and two did not. Researchers sifted through the samples and found an average of 800 microplastics per ounce of tissue. They noted the prevalence of transparent filaments, suggesting the digestive system bleached the particles, an indication that the colorants and other ad- ditives in microplastics leach out in this hot and acidic environment, though this may instead be due to the fact that single-use plastic food wrappers tend to be clear, so the patients could have eaten already-trans- parent microplastics