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Microplastic Survey
The Yokohama Institute of Environmental Science conducts a fixed-point survey to understand the actual situation of microplastics (fine plastics less than 5 mm in size) in rivers in the city.
Last Updated May 16, 2024
Results of fixed-point survey
| Date of investigation | Microplastic number density (individual/m3) ※1 | ||||
|---|---|---|---|---|---|
Tsurumi River | Katabira River | Kashio River | |||
January, 2024 (R5 Winter) | Left bank 4.4 | 1.6 | 0.86 | ||
September, 2023 | Left bank 5.7 | 2.8 | 2.9 | ||
January, 2023 (R4 Winter) | Left bank 2.6 | 1.9 | 0.42 | ||
September, 2022 (R4 Summer) | Left bank 4.4 | 3.6 | 8.6 | ||
January and February 2022 (R3 Winter) | Left bank 3.9 | 2.1 | 0.57 | ||
September, 2021 (R3 Summer) | Left bank 2.0 | 2.7 | 2.3 | ||
January, 2021 (R2 Winter) | 5.0 | 1.7 | － | ||
August, 2020 (R2 Summer) | 1.3 | 2.6 | － | ||
January, 2020 (R1 Winter) | 2.1 | 2.3 | － | ||
July and August 2019 (R1 Summer) | 6.7 | 2.5 | － | ||
※The number density is calculated by dividing the number of microplastics collected by the amount of water collected (m3).
※2 Collected at the middle point from the riverbank to the opposite bank. However, only the Tsurumi River and Kamenoko Bridge are collected at the same time at the left bank side and the right bank side in addition to the middle point.
※3 The Kashio River and Yoshikura Bridge have been conducting surveys since September 2021 (R3 summer).
Please download the summary of the survey results here.
Overview of the survey results up to 2023 (PDF: 528KB)
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Inquiries to this page
Environmental Science Research Institute, Environmental Conservation Department, Green Environment Bureau
Telephone: 045-453-2550
Telephone: 045-453-2550
Fax: 045-453-2560
Email address: mk-kanken@city.yokohama.lg.jp
Page ID: 886-268-967
