Do microplastic residuals in municipal compost bioaccumulate in plant tissue?

Abstract

Conventional and biodegradable polymers present in residential and commercial organic waste have a propensity to fragment during the composting process. This research explores whether microplastic residuals present in industrially produced compost bioaccumulate in plant tissue grown in this medium. The experimental design was modeled on methodologies used in aquatic research of microplastics in bivalves to determine whether these marine research methodologies can be adapted for terrestrial applications. Of the 30 plant tissue samples grown in the industrially produced compost, the presence of suspected microplastics was observed in 57% of the samples through histological staining. Additional phytotoxicity testing and heavy metal analysis of the compost samples showed no evidence of ecotoxicity in the industrial compost. Further observation of the plant tissue and compost samples through infrared spectrometry needs to be conducted to identify the observed foreign bodies in the plant tissue as microplastics of non-organic polymer origin.