May.16.2012@09F00 update
As a countermeasure against harmful rumors related to the accident at TEPCO's Fukushima Daiichi Nuclear Power Plant, we have decided to monitor the radiation in the atmosphere at each container wharf in Tokyo Port and radioactivity in the seawater in the Port through cooperation with Tokyo Port Terminal Corporation for the time being from April 14, 2011. In the meantime, measurements of radiation in the atmosphere were conducted on every Monday and Thursday on which the inspection system can be secured. Measurements of radioactivity in the seawater were conducted everyday from Monday to Friday. The measurement results were posted on this website. Now that the inspection framework is ready, effective May 9, 2011, we will disclose the radiation dose on the surface of containers in addition to daily measurement (business days only) and disclosure of radiation amount in the atmosphere. Radiation dose on the surface of containers shall be determined by sample measurement of containers around the gates of pier head every day, which result shall be disclosed on this website.
Map of monitoring site
yReferencez
Sievert(Sv), a unit for amount of radiation, roughly indicates the
degree of effect when human body is affected by radioactivity. The
annual radiation exposure level from the natural world, such as from
outer space, air, soil, and food, is about 2,000-5,000ĘSv.iExcerpted from Tokyo Metropolitan Institute of Public Health dataj
This is about 0.23-0.57ĘSv/h when converted into hourly exposure.
Becquerel(Bq), a unit for radiation, shows the strength of radiation emitted from radioactive substances. The Nuclear Safety Commission indicates the index value regarding intake restriction of radioactive substances within tap water in "Antidisaster Measures for Nuclear Facilities"*. The index value is 300Bq/kg for radioactive iodine(1311), and 200Bq/kg for radioactive cesium (Cs).
*Source:"Antidisaster Measures for Nuclear Facilities", Nuclear Safety Commission Homepage (June 1980, Last revised 2010)(Excepted from Tokyo Metropolitan Institute of Public Health data)
iExcerpted from Tokyo Metropolitan Institute of Public Health data)
*Measurement is conducted in the morning in front of central gates in each container piers, and the average of the indicated two extreme values is recorded.
iUnitFĘSv/hj
| Area | @Oi | AAomi | BShinagawa | CCentral Breakwater Reclaimed Land | Remarks |
| May.15(Tue) | 0.07 | 0.06 | 0.06 | 0.07 | - |
| May.14(Mon) | 0.06 | 0.06 | 0.06 | 0.06 | - |
| May.11(Fri) | 0.06 | 0.06 | 0.06 | 0.05 | - |
| May.10(Thu) | 0.06 | 0.05 | 0.06 | 0.06 | - |
| May.9(Wed) | 0.06 | 0.05 | 0.07 | 0.05 | - |
| May.8(Tue) | 0.06 | 0.07 | 0.06 | 0.06 | - |
| May.7(Mon) | 0.05 | 0.05 | 0.06 | 0.06 | - |
| May.2(Wed) | 0.06 | 0.06 | 0.06 | 0.06 | - |
| May.1(Tue) | 0.06 | 0.06 | 0.06 | 0.06 | - |
Published data in 2012
Published data in 2011
*Seawater to measure is obtained at the point between Oi Container Wharf and Aomi Container Wharf in the morning.
*"ND" means that the data were blow thedetection limit (not detected).
iUnitFBq/Lj
| Type | Iodine-131 | Caesium-134 | Caesium-137 | Remarks | |
| May.15(Tue) | ND | ND | ND | - | |
| May.14(Mon) | ND | ND | ND | - | |
| May.11(Fri) | ND | ND | ND | - | |
| May.10(Thu) | ND | ND | ND | - | |
| May.9(Wed) | ND | ND | ND | - | |
| May.8(Tue) | ND | ND | ND | - | |
| May.7(Mon) | ND | ND | ND | - | |
| May.2(Wed) | ND | ND | ND | - | |
| May.1(Tue) | ND | ND | ND | - | |
Published data in 2012
Published data in 2011
*Measure radiation dose on the surface of each sample container at the gate of pier head, and disclose number of samples, maximum volume, minimum volume, average volume by pier.
*Baseline of decontamination is 3 times higher than the amount in the atmosphere. Baseline of warning (alert) is higher than 5 ĘSv/h.
iUnit: pcs,ĘSv/hj
| Area | @Oi | AAomi | BShinagawa | CCentral Breakwater Reclaimed Land | |
| May.15(Tue) | samples | 23 | 16 | 5 | 4 |
| maximum | 0.05 | 0.04 | 0.04 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.02 | 0.01 | |
| average | 0.03 | 0.03 | 0.03 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.14(Mon) | samples | 22 | 17 | 5 | 6 |
| maximum | 0.06 | 0.05 | 0.05 | 0.05 | |
| minimum | 0.02 | 0.01 | 0.02 | 0.02 | |
| average | 0.04 | 0.03 | 0.04 | 0.04 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.11(Fri) | samples | 23 | 14 | 3 | 5 |
| maximum | 0.06 | 0.04 | 0.06 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.03 | 0.02 | |
| average | 0.04 | 0.03 | 0.04 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.10(Thu) | samples | 23 | 12 | 4 | 6 |
| maximum | 0.06 | 0.05 | 0.04 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.02 | 0.02 | |
| average | 0.04 | 0.03 | 0.03 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.9(Wed) | samples | 20 | 15 | 1 | 6 |
| maximum | 0.12 | 0.05 | 0.04 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.03 | 0.02 | |
| average | 0.04 | 0.03 | 0.04 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.8(Tue) | samples | 23 | 18 | 6 | 5 |
| maximum | 0.06 | 0.05 | 0.06 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.03 | 0.02 | |
| average | 0.04 | 0.03 | 0.04 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.7(Mon) | samples | 20 | 15 | 2 | 4 |
| maximum | 0.06 | 0.05 | 0.04 | 0.05 | |
| minimum | 0.02 | 0.01 | 0.02 | 0.02 | |
| average | 0.04 | 0.03 | 0.03 | 0.03 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.2(Wed) | samples | 22 | 14 | 1 | 6 |
| maximum | 0.06 | 0.06 | 0.04 | 0.05 | |
| minimum | 0.02 | 0.02 | 0.03 | 0.03 | |
| average | 0.03 | 0.03 | 0.04 | 0.04 | |
| decontaminated | 0 | 0 | 0 | 0 | |
| May.1(Tue) | samples | 22 | 16 | 6 | 6 |
| maximum | 0.07 | 0.04 | 0.05 | 0.04 | |
| minimum | 0.02 | 0.01 | 0.03 | 0.03 | |
| average | 0.04 | 0.03 | 0.04 | 0.04 | |
| decontaminated | 0 | 0 | 0 | 0 | |
Published data in 2012
Published data in 2011