24 Oct (NucNet): Japan’s nuclear regulator says there has been “no significant increase” in the concentrations of caesium-134 (Cs-134) and caesium-137 (Cs-137) at designated sampling points compared to the previous week, even after the typhoon that passed over the Fukushima-Daiichi nuclear plant.
The Nuclear Regulation Authority also released a monitoring report of sea area radioactivity obtained from samples taken in the vicinity of the plant and in the open sea.
The report shows that from readings of Cs-134 taken at five monitoring posts in the ocean within a two-mile radius of the plant, only one reading, from 7 October 2013, was above detection limits at 1.3 becquerels per litre (Bq/ℓ).
A sample taken on 7 October showed a reading of 1.7 Bq/ℓ of Cs-137, exceeding the detection limit of 0.50 Bq/ℓ, but still well within the World Health Organisation (WHO) drinkable limit, suggesting no risk to health.
The drinkable limit is 10 Bq/ℓ, issued by the WHO in its Guidelines for Drinking Water Quality.
Plant operator Tokyo Electric Power Company started systematic monitoring of seawater in the area from 14 August 2013 as part of its strengthening of seawater monitoring.
The report is online: www.iaea.org/newscenter/news/2013/seamonitoring221013.pdf
