Benzotriazole UV-stabilizers in beached plastic resin pellets collected across the world including remote islands: Evidence of plastic-mediated long-range environmental transport (LRET) of additives

This study analyzed benzotriazole UV stabilizers (BUVSs), including UVP, UVPS, UV329, UV9, UV320, UV350, UV326, UV327, UV328, and UV234, in beached polypropylene (PP) pellets. First, the efficiency of soaking extraction in hexane was confirmed. This extraction method was then applied to 37 PP pellet samples (each sample basically consisted of 50 pellets) collected from beaches worldwide (Europe, Africa, the Middle East, Asia, Oceania, and the Americas). Twenty samples had low levels of BUVSs that were <0.2 μg/g, while 14 samples exhibited high concentrations, ranging from >1 μg/g of BUVSs (sum of the 10 BUVSs) to 70 μg/g. These high concentrations were observed only for one or two BUVS (UV326, UV327, UV329, and UV328) in individual PP pellet samples. Piece-by-piece analyses of pellets from eight locations revealed sporadic and inhomogeneous occurrences of specific BUVSs. Pellets with high concentrations of BUVSs were industrially compounded with additives and/or were recycled, and they were even found on remote islands, such as, Macquarie Island, Hawaii Island, Ogasawara Island, and Hachijo Island. The concentrations of BUVSs in pellets from remote areas were similar orders of magnitude to those observed in anthropogenically impacted areas near industrial areas, such as Sydney or Tokyo. This study demonstrates that BUVSs, as plastic additives, travel in millimeter-sized plastics across thousands of kilometers without drastic desorption or degradation. The findings highlight the need for international regulation of plastics and associated chemicals.