The presence of primary microplastics in the environment isconsidered 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.

The presence of microplastics in the environment is considered a global threat, not only for the physical damage induced to the organisms that ingest them and leachability of their constituent, but also as a potential carrier of organic and inorganic contaminants, with an interaction poorly described. Microbeads collected from four facial cleansers, with a well-known polymeric and additive composition, were used as an indicator for the sorption of polychlorinated biphenyls (PCBs) in treated urban effluents, in order to study the behavior of microplastics versus these persistent organic pollutants in water. A stock standard solution (EPA 525, 525.1 PCB mix) was used for this purpose, being a certified material produced in accordance with ISO Guide 34:2009 and ISO/IEC 17025:2005. It consists of a mixture of eight congeners: PCB1, PCB5, PCB31, PCB47, PCB91, PCB154, PCB171 and PCB200 in n-hexane (500 µg/ml of each component). Sorption experiments were carried out in batch mode, previously in bi-distilled water, and finally in treated urban effluents. PCB congeners retained by microplastics and remaining in water were further analyzed by means of gas chromatography, using a protocol previously described with an initial column temperature of 70°C and a ramp of 10°C/min up to 150°C, 3°C/min up to 200°C, and 8°C/min to a final temperature of 280°C. The sorption process proved to be reliable and repeatable both for samples in bi-distilled water and treated urban effluents, showing different interactions between the organic pollutants and the microplastics. PCB congeners with a low-molecular weight proved to be preferentially sorbed by an oxidized polyethylene included in one of the microbeads, although the maximum amount for total PCB sorption was for the facial cleanser with TiO 2 in its composition.