Polystyrene microplastics decrease dibutyl phthalate uptake and metabolism in pumpkins

100 nm PS reduced the DBP content in the roots and leaves by 25.5% and 23.4%, respectively, while inhibiting its metabolism. DBP (PS) reduced the biomass of roots and leaves by 18.8% and 18.4% (22.4% and 15.1%) respectively, although co-exposure to PS and DBP decreased pumpkin biomass, the interaction of DBP and PS was antagonistic for 300 nm PS but synergistic for 100 nm PS. The inhibition of DBP uptake and metabolism was associated with increased oxalic acid secretion, decreased root activity, and reduced carboxylate esterase activity. Biomass reduction was associated with declines in dehydrogenase and ribulose-1,5-bishosphate carboxylase activities. This study provides a theoretical basis for using arginine to enhance degradation in microplastic-contaminated farmland.