[en] Molybdenum excretion in the bile and faeces was studied in Wistar strain rats by ⁹⁹Mo radiometry. After 8 weeks when the experimental animals had ingested 336 mg Cu/kg b.wt. they were administered a dose of 6 mg Mo/kg b.wt. in form of disodium molybdate, disodium molybdate reduced with hydrazine and stabilized with ascorbic acid, or of ammonium tetrathiomolybdate. The total amount of excreted bile was 2.53±0.42 g in 4 hours. The results show that molybdenum excretion is obviously affected by the valency of the administered compound. Pentavalent molybdenum is only excreted in a negligible amount and excretion is not affected by the amount of copper in the diet. Hexavalent molybdenum in association with oxygen is excreted far more intensively but the effect of copper intake is little shown. In the administration of ammonium tetrathiomolybdate, the effect of copper on molybdenum excretion is statistically significant. (J.B.)

[en] Monitoring radioactive contamination of foods and animal produce is based on systematic checks of animal produce (e.g., milk and meat) from critical localities for residual beta activity, i.e., gross beta activity of biological material minus natural ⁴⁰K activity. The monitoring is not demanding on instruments and can also be applied to large series of samples. The measurement can then show which samples should be processed in more detail using alpha or gamma spectroscopy or radiochemical methods. The alpha and gamma spectroscopy methods are described with respect to the requirements on instrument parameters, sample preparation and measurement time. The methods are advantageous for their high accuracy, sensitivity and reproducibility. Their constraint is complicated sample preparation, complex instrumentation, the need for computer-aided evaluation, and a long determination time. (J.B.)

[en] The proceedings contain a total of 31 papers submitted to three sessions, viz.: Methodology of trace element determination in biological material (7 papers), Trace element level in biological material (12 papers), and Trace element migration in biological material (12 papers). Three papers are of interest to INIS, dealing with INAA of high weight samples in agrochemistry, with radioactive residues and with biliary excretion of various chemical forms of molybdenum in rats. (J.B.)

[en] Instrumental neutron activation analysis was applied in establishing for 30 elements the limit of detectability, reproducibility of parallel determinations characterized by the standard deviation, and the relative error of determination of an element in the analysis of one sample. The analysis was made in soil samples of 18.4 mg and 1890 mg. High weight samples were activated for 3 mins, low weight samples for 24 hours, both with a neutron flux density of 2x10¹⁷ m^-2.s^-1. The results show that short-term activation of high weight samples allows determining practically all elements which are normally determined in low weight samples using long-term activation. For most elements reproducible results can be obtained. In high weight samples, the limits of element detectability are raised, which, however, is not of significant importance in this case. Also, errors due to nonhomogeneity of the soil do not exceed, with isolated exceptions, the statistical errors in measuring activities. (J.B.)