Polymer types and additive concentrations in single-use plastic products collected from Indonesia, Japan, Myanmar, and Thailand.

Marine debris comprising single-use plastic products (SUPs) is ubiquitous in Asian coastal waters, but there is little information on the types of polymers and the concentrations of plastic additives such waste products contain. In this study, 413 SUPs randomly collected from 4 Asian countries between 2020 and 2021 were analyzed to obtain specific polymer and organic additive profiles. Polyethylene (PE), coupled with external polymers, was prominent in the inside of the SUPs, whereas polypropylene (PP) and polyethylene terephthalate (PET) were prevalent in both the insides and outsides of the SUPs. The use of different polymers in the insides and outsides of PE SUPs implies specific and complicated recycling systems are required to maintain the purity of the products. Phthalate plasticizers including dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP), and the antioxidant butylated hydroxytoluene (BHT) were prevalent in the SUPs (n = 68). High concentrations of DEHP were detected in PE bags from Myanmar (820,000 ng/g) and Indonesia (420,000 ng/g), which were an order of magnitude greater than the concentrations in PE bags collected in Japan. SUPs containing high concentrations of organic additives may be the primary source of harmful chemicals in the environment, and should be responsible for their ubiquitous distribution in ecosystems.