Microplastics associated with stranded macroalgae on an impacted estuarine beach, Rio de Janeiro, Brazil.

Microplastics (MPs) are contaminants widely distributed in marine ecosystems. Only few studies approached MP interactions with marine plants, which are considered potential traps for MPs. Here, we determined MPs' densities and types associated with stranded macroalgae on a eutrophic beach in Guanabara Bay. Our results showed that red algae exhibited higher MP densities (1.48 MPs g-1), possibly due to their more branched thalli, than green algae (0.27 MPs g-1). The predominant MP types were blue and white fragments <3 mm in size and polymers were classified as polyethylene and polyvinyl chloride in fragments, and polypropylene in fibers. The higher densities of MPs in algae seemed to be influenced by the inner bay waters. The densities of MPs associated with algae from Guanabara Bay surpassed those reported in other studies. High MPs densities increase the chances that organisms associated with algae entangle or ingest MPs, impacting their health and survival.

Nanocomposite Films of Babassu Coconut Mesocarp and Green ZnO Nanoparticles for Application in Antimicrobial Food Packaging.

In this work, novel nanocomposite films based on babassu coconut mesocarp and zinc oxide nanoparticles (ZnO NPs), synthesized by a green route, were produced for application as food packaging films. The films were prepared using the casting method containing different contents of ZnO NPs (0 wt%, 0.1 wt%, 0.5 wt%, and 1.0 wt%). The films were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), instrumental color analysis, and optical properties. The water vapor permeability (WVP) and tensile strength of films were also determined. The antimicrobial activity of the films against cooked turkey ham samples contaminated with Staphylococcus aureus was investigated. The results showed that incorporating ZnO NPs into babassu mesocarp matrices influenced the structure of the biopolymer chains and the color of the films. The BM/ZnO-0.5 film (0.5 wt% ZnO NPs) showed better thermal, mechanical, and WVP properties. Furthermore, the synergistic effect of babassu mesocarp and ZnO NPs in the BM/ZnO-0.5 film improved the antimicrobial properties of the material, reducing the microbial count of S. aureus in cooked turkey ham samples stored under refrigeration for 7 days. Thus, the films produced in this study showed promising antimicrobial packaging materials for processed foods.