Radiocaesium contamination of beef in Croatia after the Chernobyl accident.

Long-term investigations of radiocaesium activity concentrations in beef in the Republic of Croatia are presented. The radiocaesium levels in beef decreased exponentially and the effective ecological half-life of 137Cs was estimated to be 0.57+/-0.06 years for 1986-1990 period and 5.21+/-0.27 years for the 1991-2005 period. For 1986-1990 period, the effective ecological half-life of 134Cs in was estimated to be about 0.69+/-0.05 while 134Cs activity concentrations after year 1990 were below the detection limit of the instruments. The 134Cs:137Cs activity ratio in beef has been found to be similar to the ratio that has been observed in other foodstuffs and environmental samples. Radioecological sensitivity for beef meat, i.e., the transfer coefficient from fallout to sample was estimated to be 1.15x 10(-2)Bqykg(-1)/(Bqm(-2)). For an adult member of Croatian population annual effective doses received by 134Cs and 137Cs intake due to consumption of beef are small, as per caput effective dose for the overall 1986-2005 period was estimated to be 24.6microSv. Consequently, after the Chernobyl accident beef consumption was not a critical pathway for the transfer of radiocaesium from fallout to humans in Croatia.

Subtraction digital holography.

Overlapping of the desired (first-order) and undesired (zero-order) terms originating from the recorded primary-fringe patterns in digital holography is a problem without a real-time solution. We propose a procedure for suppressing the zero-order disturbance that is realizable in real time. The procedure is based on the stochastic change of the speckles in the primary-fringe patterns and on the subtraction of two such subsequent patterns. The theoretical description of the procedure is given and experimental results presented.