Simultaneous determination of persistent and emerging organic pollutants in microplastics

Microplastics have become a major concern as research has shown the overwhelming presence of these pollutants in all environmental compartments. Their role as sorbents of chemical pollutants adds a new layer of complexity to the problem, as they can behave as vectors for the transport of these substances, protecting them from degradation, while preconcentrating them. In this research, a new methodology has been developed, optimized, and validated for the determination of 45 persistent and emerging organic pollutants in different polymeric matrices (pristine polypropylene, pristine low- and high-density polyethylene and weathered polypropylene and polyethylene). The proposed methodology used a solvent extraction procedure using an orbital-shaker combined with gas chromatography with a mass spectrometry detector. Validation showed acceptable absolute recovery values, averaging between 76.0 % and 119.0 % with low relative standard deviations (< 20 %), in most cases. Matrix effect studies highlighted significant signal suppression for most pollutants. Limits of quantification of the method ranged from 0.5 to 15.0 ng/g. The proposed methodology was evaluated based on greenness, practicality and sustainability metrics. Finally, a total of fifteen samples of weathered polyethylene and polypropylene collected from Playa Grande (Canary Islands, Spain), a hotspot of microplastic arrival, were analyzed. Results revealed quantifiable amounts of various pollutants in all samples, encompassing different families (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, ultraviolet filters, etc.) with concentrations ranging from 0.6 to 176.5 ng/g in polyethylene and 0.9-105.0 ng/g in polypropylene for most samples, with occasional values exceeding this range, underscoring the potential environmental and human health impact of microplastics.