Microfibers in oceanic surface waters: A global characterization

Abstract

Microfibers are ubiquitous contaminants of emerging concern. Traditionally ascribed to the “microplastics” family, their widespread occurrence in the natural environment is commonly reported in plastic pollution studies, based on the assumption that fibers largely derive from wear and tear of synthetic textiles. By compiling a global dataset from 916 seawater samples collected in six ocean basins, we show that although synthetic polymers currently account for two-thirds of global fiber production, oceanic fibers are mainly composed of natural polymers. µFT-IR characterization of ~2000 fibers revealed that only 8.2% of oceanic fibers are synthetic, with most being cellulosic (79.5%) or of animal origin (12.3%). The widespread occurrence of natural fibers throughout marine environments emphasizes the necessity of chemically identifying microfibers before classifying them as microplastics. Our results highlight a considerable mismatch between the global production of synthetic fibers and the current composition of marine fibers, a finding that clearly deserves further attention.

Toward Balancing the Budget: Surface Macro-Plastics Dominate the Mass of Particulate Pollution Stranded on Beaches

“…Control filters contained 0-3 fibers (average 0.59 ± 1.01 SD, n = 33 controls), with 67% of controls containing 0 fibers. The fiber count from each control filter was subtracted from the matched sample count data (Suaria et al, 2020). Overall, this reduced the number of fibers counted in samples by only 6%.…”

“…This is partly because of their higher densities than larger litter items, but also because they occur throughout the beach profile, with little evidence of concentration at high shore strandlines. This presumably reflects their small size relative to the pore size in sandy beaches, allowing them to infiltrate into beaches (Chubarenko et al, 2020b) and provides another example of how microfibers behave differently in the environment from larger micro-plastic fragments (Suaria et al, 2020).…”

“…Previous studies have tended to assume that most, if not all, microfibers found in beaches are synthetic (e.g., Nel et al, 2017;de Villiers, 2018). However, Suaria et al (2020) found that only 8% of microfibers collected in surface waters at sea are synthetic, and they are probably best treated as a separate class of pollutant to micro-plastics. The fibers in our study (median length 0.52 mm, IQR 0.42-1.02) were roughly half the length of fibers sampled at sea in the Atlantic Ocean (median 1.11 mm, IQR 0.71-1.85, Suaria et al, 2020), which might reflect mechanical degradation in the high-energy beach environment (Chubarenko et al, 2020a).…”

“…However, Suaria et al (2020) found that only 8% of microfibers collected in surface waters at sea are synthetic, and they are probably best treated as a separate class of pollutant to micro-plastics. The fibers in our study (median length 0.52 mm, IQR 0.42-1.02) were roughly half the length of fibers sampled at sea in the Atlantic Ocean (median 1.11 mm, IQR 0.71-1.85, Suaria et al, 2020), which might reflect mechanical degradation in the high-energy beach environment (Chubarenko et al, 2020a). However, the tendency for fibers to be longer in deeper sediments (Figure 3) is counterintuitive and this pattern needs to be confirmed.…”

“…However, the tendency for fibers to be longer in deeper sediments (Figure 3) is counterintuitive and this pattern needs to be confirmed. We clearly need a better understanding of the dynamics of microfibers in natural systems (Suaria et al, 2020), including how fibers are distributed within beaches and their impacts on beach biota. Yet despite their overwhelming numerical dominance, microfibers contribute a vanishingly small amount to the mass of plastic.…”