Organic additive release from plastic to seawater is lower under deep-sea conditions

Plastic garbage patches at the ocean surface are symptomatic of a wider pollution affecting the whole marine environment. Sinking of plastic debris increasingly appears to be an important process in the global fate of plastic in the ocean. However, there is insufficient knowledge about the processes affecting plastic distributions and degradation and how this influences the release of additives under varying environmental conditions, especially in deep-sea environments. Here we show that in abiotic conditions increasing hydrostatic pressure inhibits the leaching of the heaviest organic additives such as tris(2-ethylhexyl) phosphate and diisononyl phthalate from polyethylene and polyvinylchloride materials, whereas deep-sea and surface marine prokaryotes promote the release of all targeted additives (phthalates, bisphenols, organophosphate esters). This study provides empirical evidences for more efficient additive release at the ocean surface than in deep seawater, where the major plastic burden is supposed to transit through before reaching the sediment compartment.

Phthalate Plasticizers in Children’s Products and Estimation of Exposure: Importance of Migration Rate

Plasticizers are added to diverse consumer products including children’s products. Owing to their potential for endocrine disruption, the use of phthalate plasticizers is restricted in many children’s products. In this study, exposure to five phthalate esters (dibutylphthalate, di(2-ethylhexyl) phthalate (DEHP), diethyl phthalate, di-isobutyl phthalate, and diisononyl phthalate (DINP)) and an alternative (di-ethylhexyl adipate) was assessed by the use of children’s products based on chemical analysis of 3345 products purchased during 2017 and 2019 in Korea. Plasticizers were found above the detection limits in 387 products, and DEHP and DINP were the two most predominantly detected plasticizers. Deterministic and probabilistic estimation of the margin of exposure at a screening level revealed that the use of children’s products might be an important risk factor. However, it is also highly likely that the exposure could be overestimated, because the migration rate was estimated based solely on the content of plasticizers in children’s products. Chemical migration is a key process determining the absorption of plasticizers from products; thus, further refinements in experimental determination or model estimation of the migration rate are required.