p14 The Nuclear Safety Commission of Japan, a unit of the Government of Japan established the guideline value for restriction for intake of drinking water as:
I-131 300Bq/kg Cesium-134, -137 200Bq/kg
WHOによると、この↑日本政府の暫定規制値は国際的な基準より厳しいものらしい それとI-131は低比放射性物質(low specific activity)なので放射線のソースとはならないとも 核種ごとの国際的な基準は
It should also be noted that the Japanese guideline value is an order lower than the internationally agreed Operational Intervention Levels (OIL's) for I-131 (3,000 Bq/kg), Cs-134 (1,000 Bq/kg) and Cs-137 (2,000 Bq/kg). Iodine-131 is not a significant source of radiation because of its low specific activity (ref. IAEA General Safety Guide No. 2) http://www-pub.iaea.org/MTCD/publications/PDF/Pub1467_web.pdf
これ↑のp41以下 TABLE 10. DEFAULT RADIONUCLIDE SPECIFIC OILs FOR FOOD, MILK AND WATER CONCENTRATIONS FROM LABORATORY ANALYSIS に放射性核種ごとの暫定規制値が載ってる
*低比放射性物質(LSA:Low specific activity material)とは比放射能が低いため