FIRST EVIDENCE OF METAL-CONJUGATED POLYSTYRENE MICROPLASTICS IMPACT ON THE XENOPUS LAEVIS DEVELOPMENT

Microplastics (MPs), the small plastic particles no larger than 5 mm in size, are composed of different polymers derived mainly from petroleum (PVC, PET, PE, PP or PS)1. They can be classified into primary, intentionally produced, and secondary, mainly from the fragmentation of larger plastic objects through physical, chemical and biological processes2. Metals have a ubiquitous distribution and, as MPs, are bioaccumulated and biomagnified in the food chain. Multiple health effects are associated with exposure to heavy metals, with varying degrees of severity and conditions, including cancer4. Here we studied the effects of 5 μm polystyrene MPs conjugated to various metals (Cd, Cu, Pb and mix) commonly present in water and which could magnify the activity of MPs on aquatic organisms. First, the solutions were analyzed by gas chromatography to determine whether MPs release volatile organic compounds (VOCs). The FETAX test was performed on X. laevis embryos to verify the teratogenic potential of solutions containing metal-conjugated MPs and compare it to MPs alone. Preliminary results showed that the beads released significant amounts of VOCs. Treatment with MPs alone or conjugated did not affect survival, but heavily interfered with proper embryonic development by altering the expression of some early embryonic development genes, thus modifying the correct embryonic phenotype. VOCs are probably mainly responsible for the observed toxic effects; ongoing studies are highlighting the mechanism of action of individual VOCs and characterizing the effects they exert on different aspects of embryonic development.