Things appear to be on a knife-edge in Fukushima and the wild media speculation continues. The danger of further air contamination remains high, as fuel rods over-heat and become exposed to the air. Let’s hope the efforts of the military, Tokyo Denryoku and the fire service are successful. However, let me write again: a criticality event – whilst publicly not ruled out by TEPCO – is extremely unlikely as things stand and the danger to the highly populated Kanto area is being grossly exaggerated. Some figures:
Mean radiation on 17th March, measured hourly at my institute (Saitama Prefecture): 0.15μSv/h
Mean annual exposure from anthropogenic and natural sources: 3000μSv(approx.0.35μSv/h)
Radiation dose from one chest X-ray: 1000μSv
Ditto one trunk CT scan: 9900μSv
Ditto one barium enema examination: 15000μSv
Concern over the nuclear plants hopefully will not distract from the immense humanitarian effort required in the north of Japan. More than 310,000 people are living in emergency evacuation centres and many of the refugees are elderly or infirm. The most critical shortages facing the affected coastal areas are the chronic lack of fuels: diesel for transport vehicles, paraffin for heating stoves and gasoline for emergency generators. Drinking water, food, warm bedding and clothing, sanitary and infant supplies are also lacking. Chronically ill patients requiring medicines or treatment like dialysis or insulin face death. If you want to help, I highly recommend donating money or items to the Tokyo-based charity Second Harvest.