Bioplastics are materials that are biobased and/or biodegradable,
but not necessarily both. Concerns about environmental plastic pollution
are constantly growing with increasing demand for substituting fossil-based
plastics with those made using renewable resource feedstocks. For
many conventional bioplastics to completely decompose/degrade, they
require specific environmental conditions that are rarely met in natural
ecosystems, leading to rapid formation of micro-bioplastics. As global
bioplastic production and consumption/use continue to increase, there
is growing concern regarding the potential for environmental pollution
from micro-bioplastics. However, the actual extent of their environmental
occurrence and potential impacts remains unclear, and there is insufficient
mass concentration-based quantitative data due to the lack of quantitative
analytical methods. This study developed and validated an analytical
method coupling pressurized liquid extraction and pyrolysis–gas
chromatography–mass spectrometry combined with thermochemolysis
to simultaneously identify and quantify five targeted micro-bioplastics
(i.e., polylactic acid (PLA), polyhydroxyalkanoate, polybutylene succinate,
polycaprolactone, and polybutylene adipate terephthalate (PBAT)) in
environmental samples on a polymer-specific mass-based concentration.
The recovery of spiked micro-bioplastics in environmental samples
(biosolids) ranged from 74 to 116%. The limits of quantification for
the target micro-bioplastics were between 0.02 and 0.05 mg/g. PLA
and PBAT were commonly detected in wastewater, biosolids, and sediment
samples at concentrations between 0.07 and 0.18 mg/g. The presented
analytical method enables the accurate identification, quantification,
and monitoring of micro-bioplastics in environmental samples. This
study quantified five micro-bioplastic types in complex environmental
samples for the first time, filling in gaps in our knowledge about
bioplastic pollution and providing a useful methodology and important
reference data for future research.