Measurement of radiation and radioactivity in Tokyo Port

Apr.4,2024 12:00 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 and radiation dose on the surface of containers through cooperation with Tokyo Port Terminal Corporation. The measurement result shall be disclosed on this website.

・April 14, 2011 ～ May 8, 2011	atmosphere (every Monday and Thursday), seawater(from Monday to Friday)
・May 9, 2011 ～ March 31, 2013	atmosphere, seawater, container surface(from Monday to Friday)
・April 1, 2013 ～March 31, 2014	atmosphere, seawater, container surface(every Monday and Thursday)
・April 1, 2014 ～March 31, 2017	atmosphere, seawater, container surface(every Thursday (or Friday sometimes))
・April 1, 2017～	atmosphere, seawater, container surface(biweekly Thursday)

* business days only

　Map of monitoring site

・The measurement for radiation in the atmosphere and at container surfaces are conducted with support of Nippon Kaiji Kentei Kyokai, and for radioactivity in the seawater, Tokyo Metropolitan University.
・Amount of radiation in the air is measured with scintillation style survey meter 1.5 meter above ground level (1.0 meter above ground level by May 5, 2011).

1. Radiation in the atmosphere

*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.

（Unit：μSv/h）

Area	Oi	Aomi	Shinagawa	Central Breakwater Reclaimed Land	Remarks
Apr.4(Thu)	0.05	0.05	0.04	0.05	ー
Apr.1(Mon)
Feb.5(Mon)
Feb.1(Thu)	0.05	0.04	0.05	0.04	ー
Jan.15(Mon)
Jan.11(Thu)	0.06	0.04	0.04	0.05	ー
Nov.6(Mon)
Nov.2(Thu)	0.05	0.03	0.04	0.05	ー
Oct.5(Thu)	0.05	0.04	0.05	0.04	ー
Oct.2(Mon)

Published data in 2021

Published data in 2020

Published data in 2019

Published data in 2018

Published data in 2017

Published data in 2016

Published data in 2015

Published data in 2014

Published data in 2013

Published data in 2012

Published data in 2011

2. Radioactivity in the seawater (surface)

*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).

（Unit：Bq/L）

Type	Iodine-131	Caesium-134	Caesium-137	Remarks
Apr.4(Thu)
Apr.1(Mon)	ND	ND	ND	ー
Feb.5(Mon)	ND	ND	ND	ー
Feb.1(Thu)
Jan.15(Mon)	ND	ND	ND	ー
Jan.11(Thu)
Nov.6(Mon)	ND	ND	ND	ー
Nov.2(Thu)
Oct.5(Thu)
Oct.2(Mon)	ND	ND	ND	ー