Occurrence of microplastics derived from tyres in bottom sediments of Guanabara Bay, Brazil: a form of pollution that is neglected or difficult to detect?

Abstract

This study aimed to detect and characterize tyre wear particles (TWPs) in sediment samples from Guanabara Bay, an area where microplastics (MPs) have been extensively studied, but TWPs have not been specifically reported. Nine sediment samples were collected from different locations across the bay and processed using peroxide degradation to remove organic matter, followed by floatation and filtration to isolate MPs. TWPs were identified using binocular stereo microscopy, scanning electron microscopy (SEM), and Fourier transformed infrared spectroscopy. The results revealed significant quantities of TWPs in the bay sediments, although exact quantification was hindered by the particles' size variability and suboptimal sedimentation systems. These findings underscore the need for improved methodologies to accurately quantify TWPs in coastal environments, potentially through the development of specific TWP markers. Future research directions are also discussed.