Particle-particle interactions are central to the understanding of a wide spectrum of environmental, chemical, biological, and physical phenomena. Studies reported in the literature are mostly limited to single-particle species. The influence of microplastic surface properties on particle transformation or vice versa is largely missing. Microplastic particles have been shown to readily enter into different compartments of the environment. The presence of these anthropogenic particles in the aquatic environment has been hypothesized to induce long-lasting adverse effects on human and environmental health. Thus, there is a need to investigate the chemistry and toxicology related to microplastics. In this study, we defined microplastics as polymer-based particles ranging in size from 5 to 500 µm and studied the particle transformation under environmentally-relevant conditions. The behavior of microplastics within the aqueous environment depends heavily on the surrounding matrix: particles aggregate in the presence of natural organic matter, degrade in the presence of ultraviolet light and high salinity, and remain largely unchanged in pH fluctuations. We compared the particle transformation properties of three different polymeric species (Polyacryonitrile (PAN), polyethylene terephthalate (PET), and polystyrene (PS)) and observed the particle-particle interactions between silver sulfide particles with each polymeric species. Results show that UV light exposures, incubation with NOM, and increases in salinity resulted in the addition of silver in the para position of PS, nitrogen of PAN, and oxygen of PET. Nitrile, ester, and aromatic functional groups were monitored for shifts or disappearances of vibration in the FTIR analyses. Lastly, the toxicity of microplastic particles observed in algal cells was significantly higher when exposed to silver-plastic particle mixtures as opposed to either silver or plastic particle exposures alone. The goal of this research is to gain critical information on the chemical transformations and toxicological effects of microplastic mixtures in an effort to enhance strategies in achieving water sustainability in Texas.

Chemical mechanisms and toxicological effects of microplastics in the aqueous environment

2019 Spring National Meeting

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