Bridging lab and field: Tracking environmentally relevant nanoplastics in crops using Py-GC/MS

Area of Science:

• Environmental Science
• Plant Biology
• Nanotechnology

Background:

• Nanoplastics (NPs) are emerging environmental contaminants with increasing presence in terrestrial ecosystems.
• Concerns exist regarding NP bioavailability and potential impacts on crop plants, affecting food safety and agricultural sustainability.
• Understanding NP uptake and translocation in plants is crucial for accurate environmental risk assessment.

Purpose of the Study:

• To investigate the uptake and translocation of environmentally relevant polystyrene nanoplastics (eNPs-PS) in Hordeum vulgare (barley) via soil.
• To quantify eNPs-PS accumulation in barley roots and shoots.
• To assess the translocation factor (TF) of eNPs-PS from soil to barley.

Main Methods:

• Environmentally relevant polystyrene nanoplastics (eNPs-PS) were synthesized from aged polystyrene foam using a top-down approach.
• eNPs-PS were characterized using Nanoparticle Tracking Analysis (NTA) and Scanning Electron Microscopy (SEM).
• A novel acetone-assisted Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC/MS) method was developed for quantifying PS in plant tissues.

Main Results:

• Barley grown in eNPs-PS contaminated soil showed significant accumulation in roots (97.6 ± 39.4 µg/g).
• Limited translocation of eNPs-PS to shoots was observed (30.1 ± 10.1 µg/g), with a translocation factor (TF) of 0.31.
• The study provides the first experimental evidence of root uptake and systemic movement of environmentally relevant nanoplastics in plants.

Conclusions:

• The findings demonstrate substantial root accumulation and restricted translocation of eNPs-PS in barley, suggesting rhizospheric exposure as a primary concern.
• This restricted translocation indicates a potential shift in risk from food chain contamination to soil ecosystems, affecting soil organisms and microbial interactions.
• The study emphasizes the necessity of incorporating realistic nanoplastics into environmental risk assessments and developing adapted regulatory testing protocols.