Personal protective equipment, used extensively during the COVID-19 pandemic, heavily
burdened the environment due to improper waste management. Owing to their fibrous
structure, layered non-woven polypropylene (PP) disposable masks release secondary
fragments at a much higher rate than other plastic waste types, thus, posing a barely
understood new form of ecological hazard. Here we show that PP mask fragments of different
sizes induce morphogenic responses in plants during their early development. Using
in vitro systems and soil-filled rhizotrons, we found that several PP mask treatments
modified the root growth of Brassica napus (L.) regardless of the experimental system.
The environment around the root and mask fragments seemed to influence the effect
of PP fabric fragment contamination on early root growth. In soil, primary root length
was clearly inhibited by larger PP mask fragments at 1 % concentration, while the
two smallest sizes of applied mask fragments caused distinct, concentration-dependent
changes in the lateral root numbers. Our results indicate that PP can act as a stressor:
contamination by PP surgical masks affects plant growth and hence, warrants attention.
Further investigations regarding the effects of plastic pollution on plant-soil interactions
involving various soil types are urgently needed.
