Reevaluation of microplastics identification based on Neuston net survey data

Haruka Nakano; Keiichi Uchida; Tetsutaro Aikawa; Toshifumi Hayashi; Hisayuki Arakawa

doi:10.1016/j.marpolbul.2021.112799

Reevaluation of microplastics identification based on Neuston net survey data

Mar Pollut Bull. 2021 Oct:171:112799. doi: 10.1016/j.marpolbul.2021.112799. Epub 2021 Aug 5.

Authors

Haruka Nakano¹, Keiichi Uchida², Tetsutaro Aikawa³, Toshifumi Hayashi⁴, Hisayuki Arakawa⁵

Affiliations

¹ Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan; Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 395-8569, Japan. Electronic address: nakano.hrk@aist.go.jp.
² Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan. Electronic address: kuchida@kaiyodai.ac.jp.
³ Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan. Electronic address: taikaw0@kaiyodai.ac.jp.
⁴ Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan. Electronic address: aurora@kaiyodai.ac.jp.
⁵ Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan. Electronic address: arakawa@kaiyodai.ac.jp.

PMID: 34365283
DOI: 10.1016/j.marpolbul.2021.112799

Abstract

To verify data accuracy regarding microplastics (MPs), the effects of chemical preprocessing and optical identification with Fourier transform infrared spectroscopy (FTIR) were examined using survey data. We aimed to clarify the cause of overestimation of the number concentration of MPs without FTIR by focusing on shape types. The proportion of fragments (foam) decreased (increased) after FTIR analysis. Although significant difference was found in terms of the size distribution of fragments (after FTIR > before FTIR), no such difference was found with regard to foam. These findings indicate that impurities categorized as fragments via visual confirmation, especially those measuring <1000 μm, were removed using the FTIR technique. Although previous studies recommended the use of data on MPs measuring >1000 μm, this threshold should be applied only to fragments and not to foam.

Keywords: FTIR; Microplastics; Protocol; Quantification.

MeSH terms

Environmental Monitoring
Microplastics*
Plastics
Spectroscopy, Fourier Transform Infrared
Water Pollutants, Chemical* / analysis

Substances

Microplastics
Plastics
Water Pollutants, Chemical