Toxicity assessment of tire particles released from personal mobilities (bicycles, cars, and electric scooters) on soil organisms

Silent Contamination: The State of the Art, Knowledge Gaps, and a Preliminary Risk Assessment of Tire Particles in Urban Parks

“…In Selonen et al’s study [ 68 ], nominal exposure concentrations of only tire particles from 0 to 15,000 mg/kg d.w. showed a decreasing trend in survival and reproduction, but not significantly. In Kim et al’s study [ 62 ], on the other hand, TRWPs appear to reduce the growth rate in springtails at the concentration of 10,000 mg/kg d.w., probably due to the engulfment of soil pores, which stimulates springtails to expend more energy in movement or to expel ingested particles; furthermore, reproduction rates appeared to decrease in TRWP treatments, albeit not in a statistically significant way. Springtails have also been shown to ingest them, showing the potential role of the particles’ toxicity.…”

“…TRWPs have been shown to negatively affect plant growth by inducing an alteration in photosynthetic activity and polyphenolic composition, modifying soil pH, and changing litter respiration and decomposition processes [ 62 , 100 ].…”

“…Specifically, TRWPs from different vehicles have been observed to alter plant homeostasis differently; bikes and e-scooters in fact reduce leaf and sprout growth, as well as altering polyphenolic biomarkers, reducing anthocyanin and flavonoid levels, and increasing nitrogen balance [ 62 ]. In addition, the photosynthetic activity of some parameters of photosystem II (PSII) was altered differently according to the TRWPs: the steady-state PSII efficacy (QYLss), the photochemical hardening coefficient (qP), and the fraction of open PSII centers (qL) were reduced in V. radiata leaves exposed to TRWPs from cars and bikes, while they increased in those exposed to TRWPs from e-scooters [ 62 ]. These three parameters are related to the photosynthesis of PSII and generally decrease when the photosynthetic activity of chlorophyll-a in PSII is inhibited; instead, polyphenolic compounds, such as anthocyanins and flavonoids, protect plants from reactive oxygen species by neutralizing cellular ROS levels.…”

“…The PNEC values related to the compounds have been reported in the literature (ECHA website; EU website, ref. [ 105 ]) and the PNEC for the TRWPs was determined starting from the most conservative data found in the literature (10,000 mg/kg on growth in F. candida ) [ 62 ] and applying an assessment factor (AF) of 1000, as reported by the ECHA guidelines. It was not possible to determine the PNEC of some co-formulas, due to the paucity of data in the literature on the toxic effects of these substances in soil.…”

Delivery rate alters the effects of tire wear particles on soil microbial activities

“…The global average emission of TWPs has reached 0.81 kg per year per capita [8], and recent research has reported the potential effects of TWPs on soil ecosystem. TWPs can induce adverse effects on survival and reproduction of soil fauna [9,10,4,11], plant growth [12], and microbial activities [12,13], and these effects have been underpinned with multiple pathways [3]. For instance, TWPs can physically damage the intestine of soil fauna [11], and in uence soil microbial activities through changing soil properties and nutrient cycles [3].…”