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- Preliminary figures of water quality measurement results in sea areas (FY2021)
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Preliminary figures of water quality measurement results in sea areas (FY2021)
On this page, based on the public water quality measurement plan formulated by Kanagawa Prefecture, hydrogen ion concentration (pH), chemical oxygen demand (COD), dissolved oxygen (DO), measured at seven locations in the sea area based on the public water quality measurement plan formulated by Kanagawa Prefecture. For total nitrogen (N) and total phosphorus (P), the monthly average of the FY2021 survey is shown (6 months for total nitrogen and total phosphorus is shown for total phosphorus is shown for total nitrogen and total phosphorus, 6 months). Note that the measured values are preliminary figures and may be revised at a later date during the data determination process.
Last update date April 1, 2024
Changes in monthly average values of sea areas
Click here for the layout of the measurement point.
Hydrogen ion concentration (pH)
| Water area name | Name of measurement point | Environment Criteria Type |
Collection Position |
4 MON 7 SUN |
5 MON 12 SUN |
6 MON 2 SUN |
7 MON 7 SUN |
8 MON 4 SUN |
9 MON 17 SUN |
10 MON 6 SUN |
11 MON 10 SUN |
12 MON 14 SUN |
1 MON 5 SUN |
2 MON 2 SUN |
3 MON 2 SUN |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | Estuary of Tsurumi River | Ｃ | Surface layer | 8.0 | 8.1 | 8.3 | 7.5 | 8.4 | 8.1 | 8.0 | 8.0 | 7.9 | 8.2 | 8.1 | 8.0 |
| Lower layer | 8.2 | 8.3 | 8.3 | 7.9 | 8.2 | 8.3 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.2 | |||
| All layers | 8.1 | 8.2 | 8.3 | 7.7 | 8.3 | 8.2 | 8.1 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| Yokohama Port | Ｃ | Surface layer | 8.1 | 8.6 | 8.6 | 8.0 | 8.6 | 8.8 | 8.4 | 8.1 | 7.8 | 8.1 | 8.1 | 8.3 | |
| Lower layer | 8.1 | 8.3 | 8.2 | 7.9 | 8.0 | 8.2 | 8.0 | 8.1 | 7.9 | 8.1 | 8.0 | 8.1 | |||
| All layers | 8.1 | 8.5 | 8.4 | 8.0 | 8.3 | 8.5 | 8.2 | 8.1 | 7.9 | 8.1 | 8.1 | 8.2 | |||
| Tokyo Bay 7 | Offshore Isogo | Ｃ | Surface layer | 8.2 | 8.3 | 8.5 | 8.5 | 8.3 | 8.6 | 8.3 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 |
| Lower layer | 8.2 | 8.2 | 8.4 | 8.0 | 8.2 | 8.5 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| All layers | 8.2 | 8.3 | 8.5 | 8.3 | 8.3 | 8.6 | 8.3 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| Tokyo Bay 10 | In Hiragata Bay | Ｂ | Surface layer | 8.2 | 8.1 | 8.7 | 8.2 | 8.1 | 8.7 | 8.1 | 8.0 | 7.9 | 8.3 | 8.1 | 8.2 |
| Lower layer | 8.2 | 8.1 | 8.5 | 8.1 | 8.2 | 8.6 | 8.1 | 8.1 | 7.9 | 8.3 | 8.1 | 8.2 | |||
| All layers | 8.2 | 8.1 | 8.6 | 8.2 | 8.2 | 8.7 | 8.1 | 8.1 | 7.9 | 8.3 | 8.1 | 8.2 | |||
| Tokyo Bay 12 | Offshore Honmoku | Ｂ | Surface layer | 8.2 | 8.4 | 8.6 | 8.4 | 8.4 | 8.7 | 8.3 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 |
| Lower layer | 8.1 | 8.3 | 8.0 | 7.8 | 8.0 | 7.9 | 7.9 | 8.0 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| All layers | 8.2 | 8.4 | 8.3 | 8.1 | 8.2 | 8.3 | 8.1 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| Offshore Tomioka | Ｂ | Surface layer | 8.2 | 8.4 | 8.5 | 8.4 | 8.4 | 8.6 | 8.3 | 8.1 | 8.0 | 8.2 | 8.1 | 8.2 | |
| Lower layer | 8.2 | 8.4 | 8.2 | 8.0 | 8.1 | 8.5 | 8.1 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| All layers | 8.2 | 8.4 | 8.4 | 8.2 | 8.3 | 8.6 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.2 | |||
| Offshore Hiragata Bay | Ｂ | Surface layer | 8.2 | 8.4 | 8.5 | 8.2 | 8.3 | 8.6 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |
| Lower layer | 8.2 | 8.3 | 8.1 | 8.0 | 8.0 | 8.3 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 | |||
| All layers | 8.2 | 8.4 | 8.3 | 8.1 | 8.2 | 8.5 | 8.2 | 8.1 | 8.0 | 8.2 | 8.1 | 8.1 |
Chemical Oxygen Demand (COD) ： (mg/l)
| Water area name | Name of measurement point | Environment Criteria Type |
Collection Position |
4 MON 7 SUN |
5 MON 12 SUN |
6 MON 2 SUN |
7 MON 7 SUN |
8 MON 4 SUN |
9 MON 17 SUN |
10 MON 6 SUN |
11 MON 10 SUN |
12 MON 14 SUN |
1 MON 5 SUN |
2 MON 2 SUN |
3 MON 2 SUN |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | Estuary of Tsurumi River | Ｃ | Surface layer | 3.6 | 4.2 | 6.9 | 3.4 | 5.7 | 3.9 | 4.6 | 4.7 | 2.2 | 2.1 | 2.1 | 3.7 |
| Lower layer | 2.6 | 3.7 | 3.0 | 2.3 | 2.0 | 2.6 | 2.6 | 1.8 | 1.4 | 2.4 | 2.2 | 3.1 | |||
| All layers | 3.1 | 4.0 | 5.0 | 2.9 | 3.9 | 3.3 | 3.6 | 3.3 | 1.8 | 2.3 | 2.2 | 3.4 | |||
| Yokohama Port | Ｃ | Surface layer | 2.9 | 7.9 | 7.8 | 4.3 | 4.2 | 5.7 | 4.7 | 3.1 | 1.0 | 2.3 | 2.1 | 2.8 | |
| Lower layer | 2.5 | 2.3 | 2.6 | 2.1 | 2.0 | 2.1 | 0.8 | 1.3 | 1.0 | 2.2 | 1.9 | 3.1 | |||
| All layers | 2.7 | 5.1 | 5.2 | 3.2 | 3.1 | 3.9 | 2.8 | 2.2 | 1.0 | 2.3 | 2.0 | 3.0 | |||
| Tokyo Bay 7 | Offshore Isogo | Ｃ | Surface layer | 1.5 | 3.2 | 3.8 | 5.3 | 2.9 | 2.7 | 2.2 | 4.8 | 1.5 | 2.0 | 2.0 | 1.9 |
| Lower layer | 2.5 | 1.5 | 2.6 | 1.9 | 1.9 | 2.6 | 1.0 | 1.3 | 1.2 | 2.5 | 2.1 | 2.0 | |||
| All layers | 2.0 | 2.4 | 3.2 | 3.6 | 2.4 | 2.7 | 1.6 | 3.1 | 1.4 | 2.3 | 2.1 | 2.0 | |||
| Tokyo Bay 10 | In Hiragata Bay | Ｂ | Surface layer | 2.7 | 2.6 | 7.2 | 2.9 | 2.9 | 4.9 | 1.9 | 2.2 | 1.8 | 3.1 | 2.1 | 1.7 |
| Lower layer | 3.4 | 2.5 | 3.8 | 4.0 | 3.5 | 3.3 | 2.0 | 1.3 | 1.7 | 2.9 | 2.1 | 1.9 | |||
| All layers | 3.1 | 2.6 | 5.5 | 3.5 | 3.2 | 4.1 | 2.0 | 1.8 | 1.8 | 3.0 | 2.1 | 1.8 | |||
| Tokyo Bay 12 | Offshore Honmoku | Ｂ | Surface layer | 2.6 | 3.1 | 4.4 | 6.7 | 3.3 | 3.8 | 2.4 | 4.9 | 0.9 | 1.8 | 2.2 | 2.0 |
| Lower layer | 0.8 | 1.5 | 0.9 | 1.9 | 1.4 | 0.6 | 1.2 | 0.8 | 1.9 | 1.7 | 2.0 | 1.6 | |||
| All layers | 1.7 | 2.3 | 2.7 | 4.3 | 2.4 | 2.2 | 1.8 | 2.9 | 1.4 | 1.8 | 2.1 | 1.8 | |||
| Offshore Tomioka | Ｂ | Surface layer | 2.1 | 2.6 | 4.5 | 4.6 | 3.1 | 3.3 | 2.2 | 1.7 | 1.8 | 1.7 | 2.2 | 2.0 | |
| Lower layer | 2.7 | 1.3 |
1.2 | 1.6 | 1.0 | 2.1 | 1.4 | 1.3 | 0.8 | 1.7 | 2.2 | 1.6 | |||
| All layers | 2.4 | 2.0 | 2.9 | 3.1 | 2.1 | 2.7 | 1.8 | 1.5 | 1.3 | 1.7 | 2.2 | 1.8 | |||
| Offshore Hiragata Bay | Ｂ | Surface layer | 2.8 | 2.7 | 5.2 | 3.6 | 2.4 | 2.9 | 1.8 | 5.2 | 0.9 | 2.0 | 2.1 | 1.6 | |
| Lower layer | 2.1 | 2.0 | 1.1 | 1.3 | 0.9 | 3.1 | 1.8 | 1.2 | 0.9 | 1.8 | 1.7 | 1.5 | |||
| All layers | 2.5 | 2.4 | 3.2 | 2.5 | 1.7 | 3.0 | 1.8 | 3.2 | 0.9 | 1.9 | 1.9 | 1.6 |
Dissolved Oxygen (DO) ： (mg/l)
| Water area name | Name of measurement point | Environment Criteria Type |
Collection Position |
4 MON 7 SUN |
5 MON 12 SUN |
6 MON 2 SUN |
7 MON 7 SUN |
8 MON 4 SUN |
9 MON 17 SUN |
10 MON 6 SUN |
11 MON 10 SUN |
12 MON 14 SUN |
1 MON 5 SUN |
2 MON 2 SUN |
3 MON 2 SUN |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | Estuary of Tsurumi River | Ｃ | Surface layer | 7.1 | 8.6 | 11.7 | 4.0 | 11.2 | 10.0 | 7.8 | 7.0 | 7.5 | 8.9 | 9.3 | 10.6 |
| Lower layer | 8.2 | 9.6 | 9.0 | 4.2 | 5.7 | 9.2 | 7.3 | 6.9 | 7.4 | 9.0 | 9.4 | 10.6 | |||
| All layers | 7.7 | 9.1 | 10.4 | 4.1 | 8.5 | 9.6 | 7.6 | 7.0 | 7.5 | 9.0 | 9.4 | 10.6 | |||
| Yokohama Port | Ｃ | Surface layer | 7.8 | 15.1 | 13.7 | 7.1 | 12.2 | 14.3 | 11.3 | 7.6 | 7.4 | 8.7 | 9.5 | 12.9 | |
| Lower layer | 8.2 | 9.1 | 8.6 | 1.4 | 3.2 | 8.2 | 3.8 | 6.2 | 6.9 | 8.4 | 8.2 | 9.7 | |||
| All layers | 8.0 | 12.1 | 11.2 | 4.3 | 7.7 | 11.3 | 7.6 | 6.9 | 7.2 | 8.6 | 8.9 | 11.3 | |||
| Tokyo Bay 7 | Offshore Isogo | Ｃ | Surface layer | 8.9 | 9.7 | 13.1 | 11.8 | 8.6 | 11.6 | 9.7 | 8.2 | 8.3 | 9.0 | 9.0 | 10.1 |
| Lower layer | 8.5 | 9.5 | 10.6 | 2.6 | 6.1 | 9.9 | 6.9 | 7.3 | 8.3 | 9.0 | 9.2 | 10.0 | |||
| All layers | 8.7 | 9.6 | 11.9 | 7.2 | 7.4 | 10.8 | 8.3 | 7.8 | 8.3 | 9.0 | 9.1 | 10.1 | |||
| Tokyo Bay 10 | In Hiragata Bay | Ｂ | Surface layer | 9.2 | 9.3 | 18.4 | 8.7 | 10.0 | 14.2 | 7.6 | 7.4 | 8.2 | 11.8 | 10.6 | 10.8 |
| Lower layer | 10.1 | 8.5 | 14.4 | 7.0 | 5.2 | 15.6 | 6.2 | 7.2 | 7.8 | 11.5 | 10.6 | 10.7 | |||
| All layers | 9.7 | 8.9 | 16.4 | 7.9 | 7.6 | 14.9 | 6.9 | 7.3 | 8.0 | 11.7 | 10.6 | 10.8 | |||
| Tokyo Bay 12 | Offshore Honmoku | Ｂ | Surface layer | 9.7 | 10.0 | 14.4 | 11.2 | 8.6 | 12.9 | 9.4 | 7.7 | 8.4 | 8.9 | 9.3 | 10.9 |
| Lower layer | 7.1 | 7.9 | 6.7 | 1.6 | 5.8 | 4.8 | 3.5 | 6.1 | 7.7 | 8.4 | 9.0 | 10.0 | |||
| All layers | 8.4 | 9.0 | 10.6 | 6.4 |
7.2 | 8.9 | 6.5 | 6.9 | 8.1 | 8.7 | 9.2 | 10.5 | |||
| Offshore Tomioka | Ｂ | Surface layer | 9.4 | 9.8 | 12.1 | 9.9 | 8.5 | 12.2 | 10.0 | 7.7 | 8.8 | 9.4 | 9.1 | 10.7 |
|
| Lower layer | 9.1 | 9.3 | 9.1 | 3.7 | 5.7 | 11.0 | 6.5 | 7.4 | 8.4 | 8.9 | 9.1 | 9.4 | |||
| All layers | 9.3 | 9.6 | 10.6 | 6.8 | 7.1 | 11.6 | 8.3 | 7.6 | 8.6 | 9.2 | 9.1 | 10.1 | |||
| Offshore Hiragata Bay | Ｂ | Surface layer | 8.6 | 9.8 | 13.9 | 7.8 | 9.6 | 11.9 | 7.9 | 8.1 | 8.8 | 9.2 | 9.4 | 9.9 | |
| Lower layer | 9.3 | 8.6 | 7.0 | 3.7 | 7.9 | 9.1 | 7.8 | 7.3 | 8.5 | 9.2 | 8.8 | 9.5 | |||
| All layers | 9.0 | 9.2 | 10.5 | 5.8 | 8.8 | 10.5 | 7.9 | 7.7 | 8.7 | 9.2 | 9.1 | 9.7 |
Total nitrogen (N) ： (mg/l)
| Water area name | Name of measurement point | Environment Criteria Type |
Collection Position |
10 MON 6 SUN |
11 MON 10 SUN |
12 MON 14 SUN |
1 MON 5 SUN |
2 MON 2 SUN |
3 MON 2 SUN |
|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | Estuary of Tsurumi River | IV | Surface layer | 1.9 | 1.5 | 1.3 | 0.53 | 0.84 | 2.1 |
| Lower layer | 0.57 | 0.62 | 0.93 | 0.44 | 0.79 | 1.3 | |||
| Yokohama Port | IV | Surface layer | 0.70 | 1.0 | 1.1 | 0.60 | 0.79 | 0.69 | |
| Lower layer | 0.41 | 0.41 | 0.75 | 0.56 | 0.80 | 0.82 | |||
| Tokyo Bay 7 | Offshore Isogo | IV | Surface layer | 0.31 | 0.84 | 0.60 | 0.53 | 0.86 | 0.61 |
| Lower layer | 0.32 | 0.32 | 0.59 | 0.53 | 0.52 | 0.59 | |||
| Tokyo Bay 10 | In Hiragata Bay | III | Surface layer | 0.46 | 0.54 | 0.71 | 0.57 | 0.42 | 0.42 |
| Lower layer | 0.33 | 0.43 | 0.64 | 0.53 | 0.37 | 0.34 | |||
| Tokyo Bay 12 | Offshore Honmoku | IV | Surface layer | 0.32 | 1.0 | 0.67 | 0.48 | 0.67 | 0.51 |
| Lower layer | 0.39 | 0.85 | 0.49 | 0.44 | 0.47 | 0.40 | |||
| Offshore Tomioka | IV | Surface layer | 0.27 | 0.55 | 0.58 | 0.54 | 0.49 | 0.52 | |
| Lower layer | 0.22 | 0.40 | 0.52 | 0.45 | 0.45 | 0.40 | |||
| Offshore Hiragata Bay | III | Surface layer | 0.23 | 1.1 | 0.64 | 0.45 | 0.41 | 0.36 | |
| Lower layer | 0.29 | 0.40 | 0.59 | 0.46 | 0.41 | 0.38 |
Total phosphorus (P) ： (mg/l)
| Water area name | Name of measurement point | Environment Criteria Type |
Collection Position |
10 |
11 |
12 |
1 |
2 |
3 |
|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | Estuary of Tsurumi River | IV | Surface layer | 0.22 | 0.17 | 0.10 | 0.050 | 0.061 | 0.11 |
| Lower layer | 0.089 | 0.063 | 0.084 | 0.050 | 0.057 | 0.068 | |||
| Yokohama Port | IV | Surface layer | 0.096 | 0.10 | 0.10 | 0.061 | 0.068 | 0.047 | |
| Lower layer | 0.077 | 0.058 | 0.075 | 0.062 | 0.054 | 0.052 | |||
| Tokyo Bay 7 | Offshore Isogo | IV | Surface layer | 0.044 | 0.12 | 0.056 | 0.045 | 0.048 | 0.030 |
| Lower layer | 0.050 | 0.054 | 0.057 | 0.047 | 0.040 | 0.031 | |||
| Tokyo Bay 10 | In Hiragata Bay | III | Surface layer | 0.062 | 0.072 | 0.077 | 0.068 | 0.034 | 0.029 |
| Lower layer | 0.061 | 0.052 | 0.068 | 0.061 | 0.033 | 0.031 | |||
| Tokyo Bay 12 | Offshore Honmoku | IV | Surface layer | 0.056 | 0.14 | 0.070 | 0.046 | 0.045 | 0.031 |
| Lower layer | 0.072 | 0.042 | 0.054 | 0.045 | 0.037 | 0.029 | |||
| Offshore Tomioka | IV | Surface layer | 0.041 | 0.068 | 0.061 | 0.045 | 0.037 | 0.028 | |
| Lower layer | 0.048 | 0.057 | 0.056 | 0.048 | 0.034 | 0.029 | |||
| Offshore Hiragata Bay | III | Surface layer | 0.044 | 0.15 | 0.068 | 0.044 | 0.038 | 0.032 | |
| Lower layer | 0.038 | 0.059 | 0.061 | 0.044 | 0.035 | 0.031 |
For inquiries to this page
Environmental Pollution Monitoring Center Environmental Management Division, Environmental Conservation Department, Green Environment Bureau
Phone: 045-671-3507
Phone: 045-671-3507
Fax: 045-681-2790
Email address: mk-kankyokanri@city.yokohama.lg.jp
Page ID: 177-681-409
