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. 137Cs activity concentrations in pilchards. By fitting the measured. 137Cs 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 137Cs in pilchards has been observed. Estimated annual effective doses received by 134Cs and 137Cs 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 134Cs/137Cs 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 l kg-1, which is consistent with the values observed elsewhere. (authors)