Microbeads in Commercial Facial Cleansers: Threatening the Environment

The presence of primary microplastics in the environment is considered a major concern because of three main reasons: the physical damage to organisms that ingest them, the leaching of constituent contaminants such as monomers or additives, and the sorption of inorganic and organic chemicals. Microbeads collected from four facial cleansers, a personal care product commonly used by European consumers, have been analyzed in this paper. The variability in size distribution, specific surface area, the oxidation state of the polymer and the presence of whitening agents in one of the cosmetic formulations proved to be related with the ability to sorb heavy metals and polychlorinated biphenyls (PCBs), both in bi-distilled water and treated urban effluents. The sorption process for heavy metals proved to be related to a physical mechanism, without a specific interaction between the adsorbate and the microbead. In the case of PCBs, low molecular weight congeners proved to be preferentially sorbed by oxidized polyethylene (Microbead-B, MB-B), although the maximum amount for total PCBs sorption was for the facial cleanser with TiO2 in its composition (Microbead-A, MB-A) and a moderate ecotoxicity. Regression models developed for PCBs showed a similar behavior of these pollutants in bi-distilled and real treated urban effluents for microbeads, indicating that the exposed surface area was not the only mechanism responsible for sorption, but also the specific partitioning into the bulk microplastic.