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- Preliminary results of water quality measurement in sea areas (FY2021)
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Preliminary results of water quality measurement in sea areas (FY2021)
On this page, based on the public water body water quality measurement plan formulated by Kanagawa Prefecture, hydrogen ion concentration (pH), chemical oxygen demand (COD), dissolved oxygen (DO), and total nitrogen (N) and total phosphorus (P) are measured at seven locations in the sea area, showing changes in the monthly average value of the 2021 survey (total nitrogen and total phosphorus). Note that the measured values are preliminary values and may be corrected at a later date during the data confirmation process.
Last update date April 1, 2024
Changes in the monthly average of sea areas
Click here for the layout of the measurement point.
Hydrogen ion concentration (pH)
| Name of water area | 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 | At the mouth of the 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 | |||
| In 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 | |||
| Off the coast of 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)
| Name of water area | 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 | At the mouth of the 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 | |||
| In 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 | |||
| Off the coast of 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 amount (DO) ： (mg/l)
| Name of water area | 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 | At the mouth of the 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 | |||
| In 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 | |||
| Off the coast of 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)
| Name of water area | 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 | At the mouth of the 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 | |||
| In 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 | |||
| Off the coast of 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 |
All phosphorus (P) ： (mg/l)
| Name of water area | Name of measurement point | Environment Criteria Type |
Collection Position |
10 |
11 |
12 |
1 |
2 |
3 |
|---|---|---|---|---|---|---|---|---|---|
| Tokyo Bay 6 | At the mouth of the 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 | |||
| In 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 | |||
| Off the coast of 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 |
Inquiries to this page
Environmental Pollution Monitoring Center, Environmental Management Division, Environmental Protection Department, Green Environment Bureau
Telephone: 045-671-3507
Telephone: 045-671-3507
Fax: 045-681-2790
Email address: mk-kankyokanri@city.yokohama.lg.jp
Page ID: 177-681-409
