Nice example of alarmism and hysteria! Well, we do not live in a vacuum! Perhaps, this is another reason to move towards controlled indoor agriculture or synthetic food!
If rubber abrasion particles were such a serious issue, then most urban dwellers would not live past age 30-40 or so.
Some of these experiments are quite unrealistic! So don't loose your appetite over it! Remember, almost everything can be poison depending on dosage and exposure even clean natural water!
"... A new study out of the University of Vienna (UV) shows that lettuce readily takes up particles produced from rubber car tires as they roll along our roadways. ...
As rubber tires carry us around, they create microscopic tire wear particles (TWP) that include antioxidants, vulcanization accelerators, activators, processing aids, and plasticizers. These particles find their way into the environment at the rate of about 1 kg per person per year, say the researchers. Eventually the particles wind up in farmland soil through a combination of atmospheric deposits, roadway runoff, and sludge from wastewater treatment plants used by farmers as fertilizer. In fact, according to the researchers, about 93% of TWP remain after wastewater has passed through these plants, with one estimate stating that between 1,400 and 2,800 tons of TWP each year are spread on farmland in Germany alone. ...
To find out, lettuce plants were placed in a hydroponic solution into which five tire-based pollutants were added. The researchers point out that all of the compounds tested have not yet been shown to be toxic except for one: 6PPD-quinone, which has been linked to mass salmon deaths in the US Pacific Northwest. ..."
As rubber tires carry us around, they create microscopic tire wear particles (TWP) that include antioxidants, vulcanization accelerators, activators, processing aids, and plasticizers. These particles find their way into the environment at the rate of about 1 kg per person per year, say the researchers. Eventually the particles wind up in farmland soil through a combination of atmospheric deposits, roadway runoff, and sludge from wastewater treatment plants used by farmers as fertilizer. In fact, according to the researchers, about 93% of TWP remain after wastewater has passed through these plants, with one estimate stating that between 1,400 and 2,800 tons of TWP each year are spread on farmland in Germany alone. ...
To find out, lettuce plants were placed in a hydroponic solution into which five tire-based pollutants were added. The researchers point out that all of the compounds tested have not yet been shown to be toxic except for one: 6PPD-quinone, which has been linked to mass salmon deaths in the US Pacific Northwest. ..."
"Wind, sewage sludge, and waste water carry tire wear particles from roads onto farmland. ... Researchers at the Centre for Microbiology and Environmental Systems Science (CMESS) at the University of Vienna have investigated whether chemicals released from tires find their way into lettuce plants and could ultimately end up on our plates. Their analyses showed: The lettuce took up all the compounds studied - some of them highly toxic. Further investigations are to show how this process actually takes place in arable soils. The study has now been published in the international journal Environmental Science & Technology."
From the abstract:
"Tire wear particle (TWP)-derived compounds may be of high concern to consumers when released in the root zone of edible plants. We exposed lettuce plants to the TWP-derived compounds diphenylguanidine (DPG), hexamethoxymethylmelamine (HMMM), benzothiazole (BTZ), N-phenyl-N′-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), and its quinone transformation product (6PPD-q) at concentrations of 1 mg L–1 in hydroponic solutions over 14 days to analyze if they are taken up and metabolized by the plants. Assuming that TWP may be a long-term source of TWP-derived compounds to plants, we further investigated the effect of leaching from TWP on the concentration of leachate compounds in lettuce leaves by adding constantly leaching TWP to the hydroponic solutions. Concentrations in leaves, roots, and nutrient solution were quantified by triple quadrupole mass spectrometry, and metabolites in the leaves were identified by Orbitrap high resolution mass spectrometry. This study demonstrates that TWP-derived compounds are readily taken up by lettuce with measured maximum leaf concentrations between ∼0.75 (6PPD) and 20 μg g–1 (HMMM). Although these compounds were metabolized in the plant, we identified several transformation products, most of which proved to be more stable in the lettuce leaves than the parent compounds. Furthermore, continuous leaching from TWP led to a resupply and replenishment of the metabolized compounds in the lettuce leaves. The stability of metabolized TWP-derived compounds with largely unknown toxicities is particularly concerning and is an important new aspect for the impact assessment of TWP in the environment."
Uptake, Metabolism, and Accumulation of Tire Wear Particle-Derived Compounds in Lettuce (open access)
Graphical abstract
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