Microplastics and microfibers contamination in the Arno River (Central Italy): Impact from urban areas and contribution to the Mediterranean Sea

Alessio Monnanni; Valentina Rimondi; Guia Morelli; Alessia Nannoni; Alessandra Cincinelli; Tania Martellini; David Chelazzi; Marco Laurati; Laura Sforzi; Francesco Ciani; Pierfranco Lattanzi; Pilario Costagliola

doi:10.1016/j.scitotenv.2024.177113

Microplastics and microfibers contamination in the Arno River (Central Italy): Impact from urban areas and contribution to the Mediterranean Sea

Sci Total Environ. 2024 Dec 10:955:177113. doi: 10.1016/j.scitotenv.2024.177113. Epub 2024 Oct 31.

Affiliations

¹ Department of Earth Sciences, University of Florence, 50121 Florence, Italy.
² Department of Earth Sciences, University of Florence, 50121 Florence, Italy. Electronic address: valentina.rimondi@unifi.it.
³ CNR-IGG, Istituto di Geoscienze e Georisorse, 50121 Florence, Italy.
⁴ Department of Chemistry "Ugo Schiff", University of Florence, 50019, Sesto Fiorentino, Florence, Italy.
⁵ Department of Chemistry "Ugo Schiff", University of Florence, 50019, Sesto Fiorentino, Florence, Italy; Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), University of Florence, 50019, Sesto Fiorentino, Florence, Italy.

PMID: 39490839
DOI: 10.1016/j.scitotenv.2024.177113

Abstract

Fluvial ecosystems are among the main drivers of microparticles (MPC) in the form of both synthetic polymers (i.e. microplastics; MPs) and natural-based textile fibers (MF_TEX) to the seas. A wide dimensional range of MPC (5 to 5000 μm, hereafter MPC_TOT) were investigated for the first time in the Arno River waters, one of the principal rivers of Central Italy, crossing a highly anthropized landscape. Fluxes of MPC_TOT discharging to the Mediterranean Sea, one the most polluted Sea worldwide, were estimated as well. A specific sampling and analytical protocol was set up to distinguish between microplastics (MPs) and natural-based textile fibers (MF_TEX) contribution for MPC larger than 60 μm (MPC_>60), and investigate MPC smaller than 60 μm (MPC_<60) as well. Results suggest extreme MPC_TOT contamination all along the river (up to 6 × 10⁴ particles/L), strongly driven by MPC_<60, which account for >99 % of total particles found and whose abundance increases inversely with particle size. The MPC_>60 fraction (<0.5 % of MPC_TOT) highlighted a predominance (76 % of the total) of MF_TEX and synthetic polymers microfibers (e.g., PET) suggesting strong contributions from laundry effluents. Specifically, MF_TEX represent around 70 % of all MPC_>60. The metropolitan area of Florence was identified as an MPC_TOT hotspot as a consequence of the intense urbanization and possibly of over-tourism phenomenon affecting the city. The Arno River discharges approximately 4.6 × 10¹⁵ MPC_TOT annually to the Mediterranean Sea. Fluxes are highly dependent on the seasonality, with a MPC_TOT delivery of 2.4 × 10¹³ particles/day and 1.2 × 10¹² particles/day during wet and dry season, respectively. The total mass of discharged MPC_TOT is estimated at about 29 tons/year (t/y); the MPC_>60 fraction amounts to about 8 t/y, and MF_TEX to about 1 t/y.

Keywords: Fluorescence microscopy; Mediterranean Sea tributary; Microparticles flux; Microplastics; Natural-based textile fibers; μ-FTIR.