Liquid scintillation spectrometry of beta-emitters in marine samples

Liquid scintillation spectrometry has become the most widespread method for quantitative analysis of low level p-emitters in environmental samples. This technique has been applied in the measurements of (241)pu, H-3 and Sr-90 in seawater and sediment samples. Pu-241 can be measured by direct analysis of an electrodeposited source using a-p discrimination or by extraction of electrodeposited plutonium into a liquid form compatible with scintillation cocktail. Sediment from Mururoa and Fangataufa atolls showed activities ranging from 18 to 44 Bq/kg. A sediment profile sampled around Bikini Atoll in 1997 showed Pu-241 activities ranging from 0.3 to 30 Bq/kg. H-3 activities in pore water sediment from Mururoa and Fangataufa atolls were of the order of 10(3) Bq/m(3) which demonstrated its underground origin. 90Sr was measured in the presence of Y-90. The counting efficiency was 92.4 +/-1.5% and the background 0.027 +/-0.001 s(-1). The average chemical recovery for 90Sr was 67 +/-3%.