Helen ApSimon founding member and Chairman of the European Association for the Science of Air Pollution. ApSimon is well known for her research into the transport of radioactivity from the Chernobyl disaster. In the immediate aftermath, Russia issued a media blackout and ApSimon was one of few European scientists to detect rising radiation levels. She modelled the nuclear fallout, calculating Chernobyl released 15 - 20 megacuries of Iodine-131 and 1 - 2 megacuries of caesium-137. During the first few weeks after the disaster, ApSimon calculated the radioactive plum covered Scandinavia and the North coast of Europe. She travelled to Hungary, Poland, Czechoslovakia
Timeline of the Fukushima Daiichi nuclear disaster of a new leak of radioactive water into the sea. The Itabashi Ward Office announces that a concentration of caesium-134 at 2,700 becquerels per kilogram – in excess of the government's provisional limit – was detected in tea processed from leaves picked on 9 May in Tokyo. The water decontamination and water recycling systems are now both functional. 100% recycled water is now used for reactor cooling, and no additional volume of contaminated water is being generated. Radioactive caesium-137 is found in Tokyo's tap water for the first time since April. Radioactive caesium from Fukushima was expected to enter the