POST-CHERNOBYL INVESTIGATIONS OF RADIOCAESIUM ACTIVITY CONCENTRATIONS IN ADRIATIC SEA PILCHARDS

Investigations in the post-Chernobyl period (1986-2009) of radiocaesium activity concentrations in Adriatic pilchards are presented. Compared with pre-Chernobyl period, the Chernobyl nuclear accident caused increase of Cs-137 activity concentrations in pilchards. By fitting the measured Cs-137 activity concentrations to the theoretical curve was estimated to be 1.5 +/- 0.4 y for 1986-90 and 5.8 +/- 0.4 y for 1991-2009 and the bimodal behaviour for the ecological half-life of Cs-137 in pilchards has been observed. Estimated annual effective doses received by Cs-134 and Cs-137 intake due to consumption for an adult member of Croatian population are small. Collective dose for the 1986-2009 period was 4.9+0.3 person-Sv. The observed Cs-134/Cs-137 activity ratio in pilchards was similar to the ratio that has been found in other environmental samples. The concentration factor for pilchards was roughly estimated to be 93.7 +/- 39.2 1 kg(-1), which is consistent with the values observed elsewhere.