Monitoring of Radiation Levels in Mie Prefecture

関連情報8(三重県の水道水と降下物の放射能測定結果について)


Information Concerning the Earthquake Centered off the Pacific Coast of the Tohoku Region (Notification No. 8, March 28, 2011)

Concerning the Monitoring of Radiation Levels in Tap Water and Precipitation in Mie Prefecture

As of March 18, 2011, the Mie Prefecture Health and Environment Research Institute has been monitoring tap water in Mie Prefecture daily for signs of radioactive contamination. The Institute has also been monitoring rainwater and atmospheric dust for radioactive particles via samples that are continuously collected 24 hours a day. Because radiation level data take 6 hours to process, observations of radiation levels are conducted once a day.

(Results)

There have been no harmful non-natural radioactive particles detected in tap water or precipitation in Mie Prefecture. However, there have been a few days when tiny amounts of Iodine-131 were detected in precipitation. The amounts detected have no affects towards the health of Mie residents.

※the term ”non-natural radioactive particles” is defined here as: particles released as a result of nuclear experimentation and/or nuclear energy production, e.g. Iodine-131 and Cesium-137.

Radioactivity monitoring data collected since March 18, 2011 can be viewed at the following website:

http://www.pref.mie.lg.jp/KOHO/HP/tohoku/data/index.htm

The aforementioned website presents data in Japanese. To help you interpret the charts on the aforementioned website, we have translated several important terms below. Please use the translation below as a reference when viewing radiation monitoring data.

(1)水道水の放射能(単位はミリベクレル/キログラム) 毎日午前10時頃更新予定

((1)Radiation levels observed in tap water (measured in units of mBq/kg), updates scheduled for approximately 10AM each day.)

試料採取日 Date(s) of sample(s) セシウム-137Cesium-137 ヨウ素-131Iodine-131
3/27( ) 不検出Not detectable 不検出Not detectable

 

(2)降下物の放射能(単位はメガベクレル/平方キロメートル)毎日午後6時頃更新予定

((2)Radiation levels observed in precipitation (measured in units of M Bq/sq km), updates scheduled for approximately 6PM each day.)

 

試料採取日 Date(s) of sample(s) セシウム-137Cesium-137 ヨウ素-131Iodine-131
3/27~3/28 検査中Currently processing data 検査中Currently processing data

 

〔Note〕Japan’s Nuclear Safety Commission has set the following upper limits for radiation in drinking water.

Cesium-137 200 Bq/kg (200,000 m Bq/kg)
Iodine-131  300 Bq/kg (300,000 m Bq/kg)
※In the event that observed radiation levels exceed the above limits, please refrain from consuming the affected water. In these cases, use of tap water for other purposes (e.g. toilet water, etc.) is still safe.

 

Radiation Exposure Q&A

東北地方太平洋沖地震により被災した福島第一原発での被ばく関連Q&A

Q&A concerning radiation from the Fukushima Daiichi Nuclear Power Plant damaged during the 2011 Tohoku Earthquake

 

Q1. Will airborne radioactive material reach Mie Prefecture?

A1. Airborne radioactive material behaves similarly to pollen. This means that it can become suspended in the air, but will move according to wind patterns, and cannot drift against the wind. Because the westerly winds over Japan blow from west to east, it is highly unlikely that radioactive material from the Fukushima Daiichi Nuclear Power Plant will reach Mie.

 

Q2. Is it necessary to wear masks and/or protective clothing when going outside?

A2. At this time, there is no indication that airborne radioactive material will reach Mie Prefecture. Even if airborne radioactive material were to reach Mie, such measures are not expected to be necessary.

 

For more information about radiation monitoring in Mie, please visit:

http://www.pref.mie.lg.jp/KOHO/HP/tohoku/data/index.htm

 

Q3. Is exposure to rain water dangerous?

A3. At this time, there is no indication that airborne radioactive material will reach Mie Prefecture. Even if airborne radioactive material were to reach Mie, exposure to rain water is not expected to be hazardous.

 

Q4. How does radiation affect the human body?

A4. Small amounts of radiation will not cause illness. However, increasingly high levels of exposure can have probabilistic effects and deterministic effects on the body, such as genetic abnormalities, nausea, cell damage, etc.

 

Example of a probabilistic effect: Receiving 100 mSv (milli seiverts) in a single dose increases an individual’s risk of developing cancer by 0.5%.

 

Example of a deterministic effect: At exposures of 200 mSv and higher, individuals begin to develop health issues.

 

 

Q5. What is the difference between radioactive material, radioactivity, and radiation?
A5. ”Radioactive material” is defined as material that possesses the quality of “radioactivity,” which is in turn defined as the quality of releasing radiation. The Japanese terms for “radioactive material” (放射性物質- houshasei busshitsu) and “radioactivity” (放射能- houshanou) are used interchangeably in Japan. “Radiation” (e.g. gamma rays), like visible light, is a form of energy. [The radiation emitted by certain substances is particularly high in energy, and can cause damage to the human body.]

 

Q6. Is it safe to consume agricultural produce from Fukushima?

A6. All produce from Fukushima undergoes screening for any radioactive material. Any produce that does not meet the required standards is not distributed to consumers; therefore, there is no risk in consuming produce from Fukushima. Thoroughly washing produce that has been distributed is also effective.

 

 

Q7. Is it safe to consume seafood from Fukushima Bay?

A7. All seafood caught in Fukushima Bay undergoes screening for any radioactive material. Any seafood that does not meet the required standards is not distributed to consumers; therefore, there is no risk in consuming seafood caught off the shores of Fukushima.

 

Source: Food Safety Edition 0317, Volume 3, 03/17/11. Notification from the Director of the Ministry of Health, Labour and Welfare, Pharmaceutical and Food Safety Bureau’s Food Safety Division.

 

 

 

Q8.How far should one move away from the plant to ensure their safety and how is time spent in an area related to exposure?

A8. As a photon, radiation behaves similarly to light. The concentration of radiation in an area is inversely proportional to the square of the distance from the radiation source (i.e. if the distance from the plant is doubled, the amount of radiation drops to a quarter of the original amount from the previous area) The radiation levels cited by the media represent the amount of exposure that an individual would receive if they stayed in the same area for one hour. (mSv per hour) In other words, an individual’s exposure depends on both the strength of radiation at the source and the amount of time spent in an area.

The radioactive material released from the plant can be suspended in the atmosphere and carried by wind. However, as long as the wind continues to blow from the West, it is likely that airborne radioactive material will be carried out to the Pacific Ocean.