Environmental radioactivity in New Zealand and Rarotonga : annual report 2007

Artificial radioactivity in the environment in New Zealand and Rarotonga monitored during 2007 continued to be at trace levels only, typical of recent years during which there has been no significant change in the radioactivity status of the environment. Atmospheric radioactivity was monitored at Kaitaia, Rarotonga and Chatham Islands; deposited radioactivity was monitored at Hokitika; and radioactivity in milk was monitored in the Waikato, Taranaki and Westland regions. The annual total beta concentration in deposition in Hokitika was 340 ± 17 Bq/m2. The annual average levels of caesium-137 (137Cs) in milk powder were: 137Cs in milk in Waikato = 0.63 ± 0.24 Bq/kg; 137Cs in milk in Taranaki = 1.05 ± 0.30 Bq/kg; 137Cs in milk in Westland = 0.50 ± 0.21 Bq/kg. (author). 6 refs., 2 tabs