Additive chemicals in plastic marine debris and their new products

Abstract

Plastic marine debris can remain in the ocean for long periods of time. Plastic products contain numerous additive chemicals, which are present in large amount (~70% by weight), and can be transferred to the marine environment. In this study, additive chemicals and persistent organic pollutants (POPs) were quantified in marine plastic debris and fishing gear, along with their corresponding new plastic products in markets, categorized by fisheries (n=35), package (n=12) and cigarette (n=7). Additive chemicals significantly higher than POPs in plastic samples (t-test, p<0.05), indicative of high use of additives in plastics. New products contained a significantly higher amount of additives than debris samples (t-test, p<0.05), implying their potential leaching or degradation during use or after disposal in the marine environment. In fisheries category, buoys generally contained high concentration of antioxidants (0.28-91 µg/g) such as 2,4-di-tert-butylphenol (2,4-DTBP) and butylated hydroxytoluene (BHT), Irgafos168, Irganox1010 and Irganox1076. Among the buoy, polyurethane covered bouy had a high amount of phthalate such as Di-(2-ethylhexyl) phthalate (DEHP; 47 µg/g). Black colored polypropylene (PP) type of buoy contained high concentration of ultraviolet stabilizers (UVs; 4.3 µg/g) and brominated flame retardants (BFRs) such as BDE 209 (3.5 µg/g) and DBDPE (200 µg/g). Polyvinyl chloride (PVC) type of rope used for aquaculture farm had a highest concentration of phthalate (DEHP, 520 µg/g) and biphenyl A (BPA; 101 µg/g), and second highest concentration of UVs (1.4 µg/g). Polyethylene (PE), polypropylene (PP), polyester (PES) and polyamide (PA) types of ropes, eel trap (PP) and net (PE) for fisheries generally had a low concentration of additive chemicals compared with buoys. Rubber bars from tires for damping material in ship contained highest concentration of tire antioxidant (6PPD-quinone; 11.4 µg/g), which is the toxic chemical responsible for killing salmon. Among the package category, plastic bag had a high amount of antioxidants (2,4-DTBP, 11.5 µg/g) and BFRs (BDE209, 5.2 µg/g). Targeted additive chemicals were detected the lowest concentration in all cigarettes samples. The present study provides quantitative information about additive chemicals contained in plastic marine debris and their new products. Further study of release, transfer, and accumulation of these additive chemicals from plastic debris to marine environment is needed.