Conchas de gastrópodes marinhos como arquivos ambientais: investigando registros de ações antrópicas por meio de microplásticos

Abstract

The presence of microplastics in marine environments has become an increasing concern due to their widespread distribution and environmental persistence. In this context, this study investigated the potential presence of microplastics incorporated into the shells of marine gastropods from Trindade Island (ES) and Ubatuba (SP), aiming to understand whether these shells can serve as records of environmental contamination. To this end, samples were analyzed using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), and thermogravimetric analysis (TGA). The results revealed a predominantly mineral composition—primarily calcium carbonate, specifically calcite and aragonite. The various analyses did not clearly identify the presence of the investigated polymers in the natural samples. Although morphological differences were observed in the residues found in samples from the two locations, these characteristics were insufficient to confirm the presence of microplastics. Tests conducted on samples spiked with polyvinyl chloride (PVC) demonstrated that thermogravimetric analysis could successfully identify the polymer when added to the shells at known concentrations. Thus, the lack of detection in natural samples does not necessarily imply the complete absence of microplastics, as they may exist at concentrations or sizes below the detection limits of the techniques employed. Consequently, these results highlight the importance of using multiple analytical techniques to investigate such contaminants and underscore the need for future studies using more sensitive methods to better understand the potential of gastropod shells as records of microplastic contamination in marine environments.