Spatio-temporal characterization of paint-related debris as a source of metals in high maritime traffic and maintenance areas from the SW Atlantic coast.

This study examines paint debris and associated metal pollution in subtidal sediments from a Southwestern Atlantic port, based on seasonal sampling at two sites with differing proximity to vessel maintenance areas. Brittle paint microparticles (p-MP) were extracted from sediments through a wet-sieving procedure, instead of a density-based method, to enhance recovery of fragile particles and were quantified, and characterized by size, color, elements, and polymer composition. Additionally, paint particles from marina/shipyard debris (p-DB), vessel surfaces (p-BS), and commercial paints (p-CP) were also characterized using XRF, SEM-EDS, and ATR-FTIR. Trace elements in sediments were sequentially extracted to assess their mobility and measured by AAS. Total p-MP abundance was higher at the nearby site (16,970 ± 8016 items/kg) than at the farther site (5733 ± 3249) (p < 0.05). In both sites, smaller particles in the 100-500 μm range predominated. SEM-EDS and XRF revealed Zn, Cu, Pb, Cr, and Sn in p-DB, p-MP, p-BS, and p-CP. Multivariate analysis showed that red particles contained mainly Cr/Pb, while gray and white particles were associated with Ti presence, and blue particles with Cu and Zn. ATR-FTIR identified compounds like acrylic, styrene, silicon, TiO2, phthalates, and epoxy. Zn and Cu levels in sediments exceeded Sediment Quality Guidelines, but only Zn exhibited significant differences between sites (p < 0.05), enrichment factors for both metals indicated moderate contamination. Results showed that vessel maintenance facilities are a substantial source of paint-polymeric debris and might be related to trace element levels on subtidal sediments.