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2020 Pollution Well Follow-up Survey
Last Updated April 2, 2024
On this page, in the polluted well tracking survey conducted by the Water and Soil Environment Division in Reiwa 2 (2020), groundwater contamination was confirmed, Yamukai 2-chome, Tsurumi-ku, Hino 5-chome, Konan-ku, Higashimatanocho, Totsuka-ku, Nakatakita 1-chome, Izumi-ku (former Izumi-cho, Izumi-ku), Shinba-ku, Arai-ku, Arai-ku, and Arai-ku, Kohoku 2-ku, and Arai-ku, and Arai-ku.
| Survey point number | Standard value | 701 | 705 | 720 | 720 | 722 | 723 |
|---|---|---|---|---|---|---|---|
| Prefectural mesh number | No, no | 2534 | 0476 | 0349 | 0349 | 1400 | 1400 |
| Name of ward | No, no | Tsurumi Ward | Konan Ward | Totsuka Ward | Totsuka Ward | Izumi Ward | Izumi Ward |
| Name of town | No, no | 2, Yakou | 5, Hino | Higashimatanocho | Higashimatanocho | 1, Nakatakita | 1, Nakatakita |
| Date of collection | No, no | October 22, 2020 | October 1, 2020 | October 1, 2020 | December 24, 2020 | October 8, 2020 | October 8, 2020 |
| Cadmium (environmental standard items) | 0.003 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| All Cyan (Environmental Standards) | Not detected | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Lead (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Hexavalent chromium (environmental standard items) | 0.05 | Unexamined | Unexamined | Unexamined | <0.02 | Unexamined | Unexamined |
| Arsenic (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Total mercury (environmental standard items) | 0.0005 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| PCB (Environmental Standard Items) | Not detected | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Dichloromethane (Environmental Standards) | 0.02 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Carbon tetrachloride (environmental standard items) | 0.002 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Vinyl chloride monomer (environmental standard items) | 0.002 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,2-dichloroethane (Environmental Standards) | 0.004 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,1-dichloroethylene (environmental standard items) | 0.1 | <0.0002 | 0.0004 | 0.0006 | Unexamined | <0.0002 | <0.0002 |
| 1,2-dichloroethylene (environmental standard items) | 0.04 | 0.086 | 0.071 | 0.0007 | Unexamined | 0.010 | 0.0082 |
| 1,1,1-trichloroethane (environmental standard items) | 1 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,1,2-trichloroethane (environmental standard items) | 0.006 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Trichloroethylene (Environmental Standards) | 0.01 | 0.012 | 0.089 | 0.0044 | Unexamined | 0.0019 | 0.0011 |
| Tetrachloroethylene (environmental standard items) | 0.01 | <0.0002 | 0.11 | 0.015 | Unexamined | 0.36 | 0.10 |
| 1,3-dichloropropene (Environmental Standards) | 0.002 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Chiulum (environmental standard items) | 0.006 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Shimadine (Environmental Standards) | 0.003 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Thiobencarb (Environmental Standards) | 0.02 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Benzene (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Cerene (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Nitrate nitrogen and nitrite nitrogen (environmental standard items) | 10 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Fluorine (Environmental Standards) | 0.8 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Boron (Environmental Standards) | 1 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,4-Dioxane (Environmental Standards) | 0.05 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Chloroform (city-specific) | 0.06 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Electric conductivity (mS/m) (General items) | No, no | 31.5 | 54.5 | 30.5 | 27.4 | 26.3 | 32.9 |
| pH (general items) | 5.8 or more 8.6 or less | 6.0 | 8.4 | 6.5 | 6.3 | 5.7 | 6.6 |
| Water temperature (°C) (General items) | No, no | 19.9 | 16.9 | 18.8 | 16.3 | 20.7 | 18.2 |
| Odor (General items) | No, no | Odorless | Odorless | Odorless | Odorless | Odorless | Odorless |
| Appearance (General items) | No, no | Colorless and transparent | Light brown | Mud | Mud | Colorless and transparent | Colorless and transparent |
| Survey point number | Standard value | 724 | 726 | 729 | 731 | 741 |
|---|---|---|---|---|---|---|
| Prefectural mesh number | No, no | 1400 | 1400 | 1309 | 2438 | 1484 |
| Name of ward | No, no | Izumi Ward | Izumi Ward | Izumi Ward | Kohoku Ward | Hodogaya Ward |
| Name of town | No, no | 1, Nakatakita | 1, Nakatakita | 2, Izumichuokita | Nippa-cho | Niimachi |
| Date of collection | No, no | October 8, 2020 | October 8, 2020 | October 8, 2020 | October 22, 2020 | October 22, 2020 |
| Cadmium (environmental standard items) | 0.003 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| All Cyan (Environmental Standards) | Not detected | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Lead (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Hexavalent chromium (environmental standard items) | 0.05 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Arsenic (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Total mercury (environmental standard items) | 0.0005 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| PCB (Environmental Standard Items) | Not detected | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Dichloromethane (Environmental Standards) | 0.02 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Carbon tetrachloride (environmental standard items) | 0.002 | Unexamined | Unexamined | Unexamined | <0.0002 | Unexamined |
| Vinyl chloride monomer (environmental standard items) | 0.002 | Unexamined | Unexamined | Unexamined | Unexamined | <0.0002 |
| 1,2-dichloroethane (Environmental Standards) | 0.004 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,1-dichloroethylene (environmental standard items) | 0.1 | <0.0002 | <0.0002 | <0.0002 | <0.0002 | Unexamined |
| 1,2-dichloroethylene (environmental standard items) | 0.04 | 0.012 | 0.0004 | <0.0004 | 0.0012 | 0.26 |
| 1,1,1-trichloroethane (environmental standard items) | 1 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,1,2-trichloroethane (environmental standard items) | 0.006 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Trichloroethylene (Environmental Standards) | 0.01 | 0.0014 | <0.0002 | <0.0002 | 0.014 | 0.10 |
| Tetrachloroethylene (environmental standard items) | 0.01 | 0.16 | 0.089 | 0.16 | <0.0002 | Unexamined |
| 1,3-dichloropropene (Environmental Standards) | 0.002 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Chiulum (environmental standard items) | 0.006 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Shimadine (Environmental Standards) | 0.003 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Thiobencarb (Environmental Standards) | 0.02 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Benzene (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Cerene (Environmental Standards) | 0.01 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Nitrate nitrogen and nitrite nitrogen (environmental standard items) | 10 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Fluorine (Environmental Standards) | 0.8 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Boron (Environmental Standards) | 1 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| 1,4-Dioxane (Environmental Standards) | 0.05 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Chloroform (city-specific) | 0.06 | Unexamined | Unexamined | Unexamined | Unexamined | Unexamined |
| Electric conductivity (mS/m) (General items) | No, no | 23.7 | 26.5 | 25.4 | 28.6 | 18.8 |
| pH (general items) | 5.8 or more 8.6 or less | 6.2 | 6.6 | 6.4 | 6.3 | 6.2 |
| Water temperature (°C) (General items) | No, no | 17.1 | 19.5 | 18.8 | 17.0 | 18.1 |
| Odor (General items) | No, no | Odorless | Odorless | Odorless | Odorless | Odorless |
| Appearance (General items) | No, no | Colorless and transparent | Colorless and transparent | Colorless and transparent | Colorless and transparent | Colorless and transparent |
(Concentration unit: mg/L)
- The standard value of pH is tap water quality standard value.
- The standard value of chloroform is the guideline value of items requiring monitoring (outside site)
Inquiries to this page
Water and Soil Environment Division, Environmental Conservation Department, Yokohama City Green Environment Bureau
Telephone: 045-671-2494
Telephone: 045-671-2494
Fax: 045-671-2809
Email address: mk-dojo@city.yokohama.lg.jp
Page ID: 113-012-643
