Plastic additives in deep-sea debris collected from the western North Pacific and estimation for their environmental loads

Plastic waste has become a growing concern in terms of marine pollution, but little information is available on plastic debris and its possible risks of chemical additives exposure in the deep-sea. This study focused on identification of polymer type and additive concentrations in 21 plastic debris collected from deep-sea of Sagami Bay, Japan and West Pacific Ocean under the Kuroshio Extension and its recirculation gyre (KERG) zone (water depth: 1388-5819 m). Polyethylene (PE) was dominant polymer (57% of the total) in samples, followed by polyvinylchloride (PVC), epoxy resin, polyester (PES), and polypropylene. In plastic additives, bis (2-ethylhexyl) phthalate (DEHP) was detected to be contained in a PVC sheet at concentration of 48%. Butylated hydroxytoluene (BHT) was also detected in PE plastic debris with median concentration of 12.000 ng/g. PCS clothes were detected to contain dyeing mixtures, 1,2,4-trichlorobenzene (1,2,4-TCB), up to 42,000 ng/g,. Knowing the estimated number of plastic debris under KE current, the minimum burden of chemical additives were estimated that 720 kg of dibutyl phthalate, 570 kg of BHT, 230 kg of DEHP, and 160 kg of 1,2,4-TCB exist on the seabed of KERG zone. This result strongly suggests that enormous amount of hazardous additives lie within plastic debris on abyssal level of the ocean. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study focused on identifying polymer types and additive concentrations in plastic debris collected from the deep-sea of Sagami Bay, Japan and the West Pacific Ocean. The results showed that hazardous additives, including DEHP and BHT, were present in significant amounts within the plastic debris, highlighting the substantial chemical burden within plastic debris at abyssal depths of the ocean.