Comparative evaluation of the carbonyl index of microplastics around the Japan coast

Murat Celik; Haruka Nakano; Keiichi Uchida; Atsuhiko Isobe; Hisayuki Arakawa

doi:10.1016/j.marpolbul.2023.114818

Comparative evaluation of the carbonyl index of microplastics around the Japan coast

Mar Pollut Bull. 2023 May:190:114818. doi: 10.1016/j.marpolbul.2023.114818. Epub 2023 Mar 27.

Authors

Murat Celik¹, Haruka Nakano², Keiichi Uchida³, Atsuhiko Isobe⁴, Hisayuki Arakawa³

Affiliations

¹ Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan. Electronic address: 8muratcelik@gmail.com.
² Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan; Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan.
³ Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan.
⁴ Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan.

PMID: 36989597
DOI: 10.1016/j.marpolbul.2023.114818

Abstract

The carbonyl index (CI) of polyethylene and polypropylene microplastics (MPs) (2950 particles) collected in coastal waters around Japan was investigated. The CI of MPs was calculated by the specified area under band technique. The mean MP CI in all samples (regardless of shape and color) was 0.69 ± 0.34 and 0.70 ± 0.34 for polyethylene and polypropylene, respectively, and there was no significant difference in the color or shape of the MPs. The polyethylene, white, and fragment MPs CI was negatively (p < 0.05) correlated with the major length of the MPs. Large MPs with relatively little deterioration were distributed along the west coast of the Sea of Japan, whereas small MPs were distributed along the east coast. Our findings of this gradual change in the deterioration of MPs, based on geographical distribution, are in accordance with literature CI-size and MP degradation hypotheses.

Keywords: Carbonyl index; Fourier Transform Infrared Spectroscopy; Microplastic; Polyethylene; Polypropylene.

MeSH terms

Environmental Monitoring / methods
Japan
Microplastics*
Plastics
Polyethylene / analysis
Polypropylenes
Water Pollutants, Chemical* / analysis

Substances

Microplastics
Plastics
Polypropylenes
Water Pollutants, Chemical
Polyethylene