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Combined contamination of tire and road wear microplastics with heavy metals in expressway tunnels: occurrence characteristics and risk assessment
Journal of Hazardous Materials2024
7 citations
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Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Score: 55
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0–100 AI score estimating relevance to the microplastics field. Papers below 30 are filtered from public browse.
This study found that dust in expressway tunnels contains extremely high levels of tire and road wear microplastics, roughly 10 to 40 times more than dust from other land-use types in the same region. The microplastics inside tunnels also carried elevated levels of heavy metals like zinc and copper. The findings highlight highway tunnels as pollution hotspots where people and the environment face concentrated exposure to tire-derived microplastics and associated metals.
Tire and road wear microplastics (TRWMPs), as an important type of microplastics, have attracted increasing attention. However, current studies on their contamination within expressway tunnels remain limited. Therefore, we investigated the occurrence characteristics of TRWMPs in dusts from various tunnels, and combined contamination with heavy metals (HMs). The results showed that the abundance of TRWMPs in expressway tunnel dust (53,778 n/kg) was much higher than that sampled from other land use types (1360-4960 n/kg) in the same region. A large amount of polyamide was released into the environment along with wear particles from the vehicles. Also, the abundance of TRWMPs inside tunnels was greater than outside, and the proportion of large-size TRWMPs was higher inside tunnels. TRWMPs was symmetrically distributed with respect to the center of expressway tunnel. The pollution load index (PLI) and ecological risk index (H) indicated that study area was heavily contaminated with TRWMPs. There was a significant positive correlation between the abundance of TRWMPs and concentration of Cr (p < 0.01) in dust, and their risk assessment and health risk fluctuations were almost identical. Thus, the study is of great significance for elucidating the synergistic contamination and potential risk of TRWMPs and HMs in expressway tunnels.