Fukushima Nuclear Accident

Radiological Implications on Human Health23 March 2011

Division of Radiation Transport and Waste SafetyDepartment of Nuclear Safety and Security

Division of Human HealthDepartment of Nuclear Science and Applications

Radiation-related Health Effects

Acute effects of radiation exposure? (Individual)NPP accident: Not likely in general population (doses NOT high enough)At risk: NPP workers, fire fighters and rescuers.

Long-term effects? (population)Increased risk of cancerRisk of thyroid cancer: Prophylaxis by iodide pills.Noted: Iodine is NOT an antidote for radiation exposure.

Risk of radiation-related health problems

Health problems depend on exposure.

• Exposure depends on:– Dose received– Duration of exposure– Distance someone is from the plant– Weather conditions

• Human beings are exposed to natural/man-made radiation on a daily basis.

• 2-3 mSv/year

• Nuclear accidents with health hazards:– External Radiation – Internal contamination– External contamination (can often be washed off

the body)

• Main radionuclides in Fukushima with health risk are:

• Iodine-131• Cesium-137• suspended air, food and drink

• Workers of NPP and civil defence teams: higher radiation doses - professional activities

Which public health actions to take?

• Prevention of exposure:– evacuation – sheltering of those near the site.

• Preventive Iodine pills to reduce the risk of thyroid cancer.

• Restriction of consumption of vegetables and dairy products produced in the vicinity of the power plant.

• Follow instructions by competent authorities

• Source: WHO

How can food products become radioactive?

• Contamination of the environment (soil, rivers, lakes, sea)

• How?– surface of foods– Or build up within plants and organisms

• Severity of health risk depends on radionuclide mix and intake

• Radioactivity cannot contaminate food that is packaged

What general advice can be given to food consumers and producers?

In early stages of an emergency:

• avoid consumption of locally produced milk, vegetables and seafood;• avoid slaughtering animals; and• avoid fishing, hunting or gathering mushrooms

or other forest foods.

• Source: WHO

Are there rules for radioactivity in foods for international trade?

Guideline Levels (GLs)• Food below these GLs is safe for people to eat• If GLs are exceeded - national policies

• Source: WHO

MeasurementsIAEA radiation monitoring team

23/03/11

• Radius 30 from 73 Km for NPP measurement of :– Dose rate: 0.2 to 6.9 microSv/ hour (background:

0.1 microSv/ hour)– Contamination: 0.02 to 0.6 Mbq/ m2

• IAEA team dispatched for further analysis of environmental contamination

Gamma Dose Rates/March 15-22(Japanese authorities/microSv/hour)

0

0.2

0.4

0.6

0.8

1

1.2

11-Saitama(Saitama)

12-Chiba(Ichihara)

13-Tokyo(Shinjyuku)

14-Kanagawa(Chigasaki)

Background: 0.1 microSv/hourIncrease since yesterdayClose monitoring needed

Daily deposition of Iodine-131 and Cesium-137 (Japanese authorities)

(Bq/m2) (Bq/m2) (Bq/m2) (Bq/m2)

Location18-19 March 2011 19-20 March 2011 20-21 March 2011 21-22 March 2011

Iodine-131 Cesium-137 Iodine-131 Cesium-137 Iodine-131 Cesium-137 Iodine-131 Cesium-137Hokkaido(Sapporo) ND ND ND ND ND ND ND ND

Aomori(Aomori) ND ND ND ND ND ND ND NDIwate(Morioka) ND ND ND 0.24 4800 690 ND ND

Miyagi - - - - - - - -Akita(Akita) ND ND ND ND ND ND 3.9 ND

Yamagata(Yamagata) ND ND 22 20 58000 4300 590 140Fukushima - - - - - - - -

Ibaraki - - 490 48 93000 13000 85000 12000Tochigi(Utsunomiya) 1300 62 540 45 5300 250 25000 440Gunma(Maebashi) 230 84 190 63 990 87 1500 72Saitama(Saitama) 64 ND 66 ND 7200 790 22000 1600

Chiba(Ichihara) 21 ND 44 3.8 160 16 710 150Tokyo(Shinjyuku) 51 ND 40 ND 2900 560 32000 5300

Kanagawa(Chigasaki) 40 ND 38 ND - - 340 110

Radioactivity in food, milk and drinking waterFukushima and Ibaraki prefectures

Japanese authority:– Cease distribution and consumption of vegetables

(broccoli, cauliflower, spinach, cabbage and the like) in Fukushima area

– Cease distribution of fresh raw milk in Ibaraki– Monitor seafood– Tap water in Tokyo is not used as drinking water

for infants

Drinking water I-131 concentration in Fukushima

14

3/16/2011 3/17/2011 3/18/2011 3/19/2011 3/20/2011 3/21/20110

50

100

150

200

250

300

350

400

Limit for Adult = 300 Bq/Kg Limit for Children= 100 Bq/Kg

IwakiTamuraMinamisoumaKawamataOno

Bq/k

g

Sea water contamination

• Sea water radionuclides concentration • Samples collected 330 m South of discharge

point (NPP Daichii NPP)• Very high above the normal range• IAEA dispatch a team to conduct marine

environmental study