We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Tire wear nanoparticles induce systemic metabolic disruptions and heavy metal accumulation in spinach
Summary
Tiny particles from worn-down tires can get absorbed by spinach plants through both their roots and leaves, and this new study found that higher levels of these particles stunted plant growth while causing toxic metals like lead and cadmium to build up in the leaves we'd eat. Since tire dust from roads regularly ends up in soil and dust that settles on crops, this research raises concerns that produce grown near roadways could carry these unwanted heavy metals, making it an important food safety issue to watch as scientists learn more.
Tire wear nanoparticles (TWPs) pose an emerging environmental concern in agricultural systems. In this study, TWPs were characterized using dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy/energy-dispersive X-ray spectroscopy, revealing predominantly submicron particles (average hydrodynamic diameter 284.6 nm), irregular morphology, and complex composition. The ICP analysis confirmed the presence of Zn, Cu, Cr, Pb, Ni, Cd, and As in the TWP matrix. A controlled pot experiment evaluated the effects of soil and foliar-applied TWPs at concentrations of 0.05–0.5 g kg−1 (soil) or g L−1 (foliar) on spinach (Spinacia oleracea L.). Fluorescence microscopy showed internalization of TWPs via both root and leaf pathways. Low soil concentration (0.05 g kg−1) transiently enhanced growth and metabolite accumulation, whereas higher concentrations (≥0.25 g kg−1 or g L−1) significantly reduced biomass, leaf area, photosynthetic traits, and growth indices. Antioxidant responses showed enzyme-specific modulation, with marked induction of peroxidase and catalase at higher TWP levels and variable superoxide dismutase responses depending on the exposure pathway. Metal analysis revealed concentration-dependent accumulation of Zn and non-essential metals, including Pb and Cd, in leaves, particularly at elevated TWP levels. These findings indicate that TWPs can enter plant tissues through both soil and foliar routes, alter morpho-metabolic processes, and promote metal accumulation, posing potential risks to food safety. This study provides a controlled evaluation of tire wear nanoparticles (TWPs) in an edible terrestrial crop by comparing two relevant exposure pathways: soil application, representing rhizosphere-mediated exposure, and foliar application, representing atmospheric deposition on leaf surfaces. Unlike many previous studies that focus mainly on aquatic systems, TWP leachates, or single-response endpoints, this work integrates particle characterization, plant internalization, growth and physiological responses, metabolite regulation, antioxidant activity, and multi-element accumulation in spinach. The findings demonstrate that TWPs are not inert particles but active stressors and multi-metal carriers that induce pathway-specific growth inhibition, metabolic disruption, and metal redistribution in edible plant tissues.