Microplastics as vectors of triclosan in aquatic environment: biological effects on freshwater microalgae

, Verdú Irene, Gonzalez-Pleiter Miguel, Rosal Roberto, Leganés Francisco, Fernandez-Piñas Francisca.

In recent years the presence of microplastics (MPs) in every ecosystem has evidenced that these particles are in contact and causing effects on the biota (1). MPs are frequently found in nature because of their incomplete retention in WWTPs (2). There, MPs can get in contact with other pollutants. Triclosan (TCS) is an antimicrobial compound used in cosmetics, and household products, reason why it is frequently found in wastewater. Some research points out that MPs can adsorb and desorb pollutants (3), but the role that these plastic particles could have as carriers of pollutants and the influence of this phenomenon on biota is even less-known. In order to know the potential of MPs to transport contaminants and their influence on the biota, in this study we have worked with 8 types of MPs beads (LDPE, PA 6'6, PET, PP, POM, PS, PLA, PCL), the antimicrobial compound TCS as pollutant and with the cyanobacterium Anabaena sp. PCC7120, primary producer in freshwater ecosystems, as model for the toxicity experiments. For 4 h MPs were exposed to TCS in water. Then, the pre-exposed beads were transferred to the culture medium in order to study desorption. To investigate the biological effects of this pre-exposed beads, the cyanobacterium cells were inoculated. After 72 h, growth and chlorophyll a content were evaluated, showing that LDPE, PA and POM were able to adsorb and desorb TCS, acting as carriers and making it bioavailable for the cyanobacterium which was affected by the desorbed TCS. These results reveal a relevant adsorption and desorption of TCS on MPs with eco-toxicological implications.

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