Marine environment microfiber contamination: Global patterns and the diversity of microparticle origins

Microplastic and microfiber pollution has been documented in all major ocean basins. Microfibers areone of the most common microparticle pollutants along shorelines. Over 9 million tons of fibers areproduced annually; 60% are synthetic and ~25% are non-synthetic. Non-synthetic and semi-syntheticmicrofibers are infrequently documented and not typically included in marine environment impactanalyses, resulting in underestimation of a potentially pervasive and harmful pollutant. We present themost extensive worldwide microparticle distribution dataset using 1-liter grab samples (n ¼ 1393). Ourcitizen scientist driven study shows a global microparticle average of 11.8 ± 24.0 particles L?1(mean ± SD), approximately three orders of magnitude higher than global model predictions. Open oceansamples showed consistently higher densities than coastal samples, with the highest concentrationsfound in the polar oceans (n ¼ 51), confirming previous empirical and theoretical studies. Particles werepredominantly microfibers (91%) and 0.1e1.5mm in length (77%), a smaller size than those captured inthe majority of surface studies. Using mFT-IR we determined the material types of 113 pieces; 57% wereclassified as synthetic, 12% as semi-synthetic, and 31% as non-synthetic. Samples were taken globally,including from coastal environments and understudied ocean regions. Some of these sites are emergingas areas of concentrated floating plastic and anthropogenic debris, influenced by distant wastemismanagement and/or deposition of airborne particles. Incorporation of smaller-sized microfibers inoceanographic models, which has been lacking, will help us to better understand the movement andtransformation of synthetic, semi-synthetic and non-synthetic microparticles in regional seas and oceanbasins.