Strontium-90 determination in environmental samples

The study to establish radiochemical methods for strontium-90 analysis in environmental samples, such as water, seawater, fish, marina sediment, soil and air filters is presented. The analyses were divided in the following steps: leaching of strontium-90 from fish, marine sediment, soil and air filter samples with nitric acid and hydrogen peroxide; strontium-90 preconcentration in seawater by using sodium carbonate and from other matrices sulfuric acid; magnesium separation in seawater matrix with ammonium chloride; separation of interferents elements, time to reach radioactive equilibrium between strontium-90 and yttrium-90; separation of strontium-90 from yttrium-90, by precipitation with hydroxide and conversion to oxalate, and beta counting of yttrium-90 in Geiger-Mueller detector with low background radiation and high counting efficiency. The methodology developed for strontium-90 analysis in environmental samples, presented a strontium-90 recuperation of about 90%, for water, 66% for seawater and higher than 80% for fish bones and muscles, marine sediment, soil and air filter samples. (author). 78 refs., 6 figs., 21 tabs