Research on Microplastics in Marine Life in the Coastal Areas of Japan [an abstract of entire text]

概要

Title

Author(s)

Citation

Issue Date

Doc URL

Research on Microplastics in Marine Life in the Coastal Areas of Japan [an abstract of entire text]

楊, 柳

北海道大学. 博士(食資源学) 甲第15584号

2023-06-30

http://hdl.handle.net/2115/90228

Type

theses (doctoral - abstract of entire text)

Note

この博士論文全文の閲覧方法については、以下のサイトをご参照ください。

Note(URL)

File Information

https://www.lib.hokudai.ac.jp/dissertations/copy-guides/

YANG_LIU_summary.pdf

Instructions for use

Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP

学 位

論

文

の

博士の専攻分野の名称： 博 士（食資源学）

要

約
氏名

楊

柳

学 位 論 文 題 名
Research on Microplastics in Marine Life in the Coastal Areas of Japan
(日本近海におけるマリンライフ中のマイクロプラスチックスの研究)
Microplastics derived from anthropogenic pollution have become a major issue today.
Available data points to their presence in all terrestrial and marine ecosystems. The body of
literature documenting their presence in many organisms is growing, including humans, where
they may cause health problems. These microplastics are from multiple sources, from trash
dumped in rivers and lakes and travelling to the ocean, fishing tools such as nets, ropes, and
baskets, to various chemicals dumped in water sources.
Marine organisms often absorb microplastics through food or directly from the water,
especially in filter-feeding species. Particles are then deposited in the respiratory organs, guts,
pallial cavity, and other organs. When these species are used as food, these particles are
transferred to the consuming organisms, where they accumulate. Oysters are an important
component of Japan’s fisheries industry, as locally consumed or exported. Their quality is of
utmost importance for the industry.
In addition, as apex predators, cetaceans are critical in regulating the food web and
maintaining ecosystem balance. Cetaceans consume lower trophic-level organisms that have
ingested microplastics. At present, studies are not enough on microplastics in cetaceans.
Further research on the prevalence and effects of microplastics in these animals is needed to
help conservation efforts and shed light on the larger issue of plastic pollution in the oceans.
Studying the levels of microplastics in cetaceans can indicate the level of microplastic
contamination in the larger marine food web, including seafood that humans consume.
The main purpose of this thesis was to study the presence and accumulation of
microplastics in maline-life, such as oysters and cetaceans, for better understanding their
potential impacts on these species and the marine environment. In the case of oysters, the
possible relationship between microplastics and food safety was discussed. The research
involved analyzing the presence of fibres and their quantification in oysters and cetaceans from
different locations and comparing the results to determine trends or patterns.

The study detected microplastics in cultured oysters, mainly in fibres and fragments, with
red and green being the most common colours. Fibres were the most common type, with an
average of 3.14 ± 4.00 particles per individual. Microplastics were found in oyster gills and
digestive systems, and the Raman spectra analysis showed they were nylon 6, high-density
polyethylene and polypropylene. Furthermore, Microplastics were detected in 13 out of 17
samples of cetacean intestines. The observed microplastics showed variations in length, size,
and colour, most of which were fibres. Raman spectroscopy analysis identified Nylon 6,6 as the
polymer present in the microplastics.
The thesis investigated the presence and accumulation of microplastics in oysters and
cetaceans. The potential impacts on these species and the marine environment were discussed.
The research also examined the potential relationship between microplastics and seafood safety
in oysters. Additionally, the thesis analyzed the potential effects of microplastics on human
health based on existing literature and discussed possible measures to reduce the impact of
microplastic pollution from a political and societal perspective. The results of the study will
contribute to the current knowledge of the impact of microplastics on marine life and
ecosystems and can aid in developing strategies to mitigate and manage this environmental
issue. ...

この論文で使われている画像