Impact of different microplastics polymers and albendazole and pyraclostrobin mix on arugula (Eruca vesicaria) physiology and growth

The combined effects of microplastics (MPs) and agrochemicals in soil pose an uncertain, growing threat to crop health and food safety. This study investigated the phytotoxicity of conventional low-density polyethylene (LDPE) and biodegradable polybutylene adipate terephthalate (PBAT) MPs, alone and combined with a mixture of albendazole and pyraclostrobin (ALB+PYR), on arugula (Eruca vesicaria). Key physiological and growth parameters were assessed throughout the experiment. The results revealed a significant synergistic toxicity specific to the conventional plastic. Co-exposure to 1 % LDPE and the ALB+PYR mixture caused the most severe effects, significantly reducing fresh and dry shoot biomass compared to controls. This synergistic toxicity was not observed for the biodegradable PBAT MPs under the same conditions. While both MP types alone induced moderate stress, evidenced by an increased root-to-shoot biomass ratio, the exacerbation of agrochemical toxicity was unique to LDPE. This suggests that conventional plastics can act as vectors for organic pollutants, a role not equally played by their biodegradable counterparts in this study. These findings demonstrate that risk assessments must consider the specific polymer type when evaluating co-contamination scenarios in agriculture.