[The features of radioactive contamination of small birds in Chernobyl zone in 2003-2005].

Radioactive contamination of small birds (484 individuals, 44 species) was investigated in the Chernobyl zone (Ukraine) in 2003-2005. Values variation of 90Sr and of 137Cs activity concentration reached 3-4 orders of magnitude even in one site, and maximum values amounted to hundreds Bq/g at the central plots of the zone. The biggest contamination is appropriate to birds in breeding season and to settled species, whilst migrants are the "cleanest". Change of contamination within a year reflects seasonal and short-term changes in birds diet and in behaviour. During breeding season females have higher activity concentration of 90Sr, while on 137Cs accumulation sexual differences are absent. In other seasons radioactive contamination of male and female does not differ if they live in similar conditions and have similar migratory behavior. Young birds during fledging and just after, as a rule, have higher levels of 90Sr contamination than adults, and actually do not differ on 137Cs accumulation. On a set of own and published data, it was assumed, that in small birds the half-life period of 137Cs extraction amounts to 1-2 days, and 90Sr- 5-10 days, and dynamic equilibrium of the radionuclides turnover in organism is reached over 4-7 and 17-34 days, respectively, after the birds arrival on the contaminated site. Among 44 studied species, those who search invertebrates in soil top layer or forest litter (thrushes). have noticeably higher accumulation of 90Sr and of 137Cs. Specific differences of radionuclides accumulation for the rest birds were not revealed due to small sample sizes of the species.

[Quantitative evaluation of 90Sr, 137Cs, 239Pu, 241Am transfer from polluted soil to gastric and intestine juice of cows]. / Otsenka kolichestvennykh pokazatelei perekhoda 90Sr, 137Cs, 239Pu, 241Am iz zagriaznennoi pochvy s zheludochnym i kishechnymi sokami korov.

Quantitative parameters of 90Sr, 137Cs, 239Pu and 241Am transfer from solid phase of soil to gastric, intestine juice of cows as well as to imitating solutions have been estimated on the base of results of laboratory incubation experiments. A prevailing role of enzyme complex and microflora of gastrointestinal tract in radionuclides transfer from solid phase of soil to solution has been shown.

[The correction of the fluorine load in caries]. / K voprosu korrektsii ftornagruzki pri kariese.

The authors discuss the problem of fluorine load correction in caries. They claim that fluorine load of the body as regards caries prevention should never surpass the safe levels of total daily fluorine consumption. In children aged over 4 the safe level of total daily fluorine consumption is 2.5 mg, in adults 4 mg.