Rastreando microplásticos em águas costeiras: um estudo de fatores ambientais usando canoa havaiana

Abstract

Microplastic (MP) pollution is an increasing environmental concern, particularly in coastal zones where terrestrial and marine sources interact intensely. These regions host various human activities, such as tourism, fishing, and navigation, while also supporting ecosystems with high biodiversity. This study assessed the density and distribution of MPs in surface waters along the semi-arid Brazilian coast using a horizontal sampler consisting of a net towed by a Hawaiian canoe, providing a low-cost and sustainable alternative for data collection. Over 12 months, sampling was conducted during spring and neap tides at two locations with different levels of urbanization: Fortaleza, a highly impacted area affected by anthropogenic activities, and Jericoacoara, a coastal marine park distant from major urban centers. The average MP density was 1.20 ± 2.30 (0.09–22.18) particles/m2 in Fortaleza and 0.39 ± 0.27 (0.05–2.06) particles/m2 in Jericoacoara. The analyses identified fibers as the predominant MP type (54.3%), followed by fragments (35.4%), with polyethylene (PE) and polypropylene (PP) being the most common polymers. The Boosted Regression Trees (BRT) model indicated wind speed as the most influential variable (26.5%), followed by location (19.5%) and monthly rainfall (12.5%). The interaction between wind direction and wave height (4.3%) confirmed the role of meteorological conditions in MP dispersion. The results highlight the influence of coastal currents, wind, and waves in modulating MP distribution and demonstrate the effectiveness of engaging Hawaiian canoe practitioners as a low-impact tool for environmental monitoring.