[Estimation of soil fraction of Pu in the formation of irradiation dose of inhabitants of the Bryansk region]. / Znachimost' "pochvennoi fraktsii" Pu v formirovanii doz oblucheniia naseleniia Brianskoi oblasti.

The estimation of plutonium in soils of the contaminated after Chernobyl accident areas of Bryansk Region (Russia) are presented. On the basis of data about Pu concentrations in soils and by means of migration models in "soil-man" system the doses received were assessed. Pu-239, 240 and Pu-238 were determined in samples of autopsy material (lung, liver, bones and tracheobronchial lymph nodes) of residents from Chernobyl-fallout contaminated regions. Effective doses have been obtained by means of data about Pu-concentration in autopsy samples.

[ Approaches to the radiation hygienic assessment of "soil components" of plutonium]. / Vozmozhnye podkhody k radiatsionno-gigienicheskoi otsenke "pochvennoi komponenty" plutoniia.

By the Pathway-analysis the correlation coefficients between the plutonium isotopic contamination of soil and the human radiation dosage were defined.

[The distribution of intratracheally administered plutonium-239 throughout the skeletal bones]. / K voprosu o raspredelenii intratrakheal'no vvedennogo plutoniia-239 po kostiam skeleta.

The data are presented on distribution of the intratracheally administered plutonium-239 within the skeleton bones. Plutonium was found to be distributed non-uniformly within the skeleton: it was concentrated mainly in the bones where the trabecular fraction of the bone tissue was most manifest. The results obtained were supported by the correlation analysis.

[The specificity of the deposition of intratracheally administered plutonium in different skeletal bones with a change in iron homeostasis]. / Spetsifika otlozheniia intratrakheal'no vvedennogo plutoniia v razlichnykh kostiakh skeleta pri izmenenii gomeostaza zheleza.

A study was made of the distribution of plutonium-239 injected intratracheally within different bones of the skeleton, the iron status in the blood being changed. The iron preparation caused a 2.5-3-fold decrease in the plutonium loading onto cancellous bone tissue that displayed, in ordinary conditions, a higher tropism to the radionuclide than a cortical highly mineralized bone did.

[The levels of soil pollution with plutonium isotopes in the Bryansk Oblast (following the accident at the Chernobyl Atomic Electric Power Station)]. / Ob urovniakh zagriazneniia pochv Brianskoi oblasti isotopami plutoniia (posle avarii na ChAES).

The estimates of plutonium concentration in soils of Western regions of Bryansk (Krasnogorsky, Novozybkovsky, Zlynkovsky and Klintsovsky) are presented. The levels of soil contamination with plutonium within the regions examined vary by 4-5 times, although no definite geographical direction of pollution intensity within the territory examined is noted. The cumulative concentration of isotopes (238Pu, 239Pu, and 240Pu) varies within 21-112 Bq/kg.

[Dosage of irradiation of the population in the Bryansk region with plutonium deposited in the soil after the Chernobyl AES accident]. / Urovni oblucheniia naseleniia Brianskoi oblasti plutoniem, otlozhivshimsia v pochve posle avarii na Chernobyl'skoi AES.

Proceeding from the data on 238Pu, 239Pu, 240Pu concentrations in the soil in different areas of the Bryansk Region, exposed to radioactive contamination after the Chernobyl accident, radiation dose exposures of residents as well as agricultural workers were assessed. Criteria of the ecological and radiation-hygienic standardization were used for calculation of values of dose factors, binding the alimentary and inhalation components of an irradiation dose with characteristics of Pu deposition in the soil. Inhalation of soil particles accounted for approximately 90% of a total radiation dose of the "soil" Pu component, and the alimentary component-for approximately 10% (of this, 99% were attributed to plant products). The authors proposed prognostic assessment of an expected effective equivalent dose for a period of 70 years for people, residing in these areas (0.08-0.45 cSi for the population and 0.6-3.2 cSi for mechanics).

[The applicability of the concept of morpho-physiologic metabolic factors to the modification of the distribution of 239Pu deposited in the respiratory organs]. / Primenimost' kontseptsii morfofiziologicheskikh faktorov obmena k modifikatsii raspredeleniia popavshego v organy dykhaniia 239Pu.

At the stage of intensive resorption of plutonium from lungs to blood the competitive per os administration of an iron preparation increased plutonium excretion from blood. As a result, soft tissues were enriched with plutonium at an early stage of metabolism. However, at the end of the experiment (30 days) the radionuclide content of soft tissues dropped to control values. Simultaneously, the share of plutonium deposited in bone tissue decreased considerably and that of the radionuclide eliminated from the body increased throughout the entire period of observation.

[239Pu metabolism after its intratracheal administration]. / Obmen 239Pu posle intratrakheal'nogo vvedeniia.

The paper is concerned with the results of distribution and kinetics of metabolism of 239Pu-citrate in the respiratory tracts. Time-periods of the accumulation and excretion of this radionuclide from various tissue systems were defined. Data on the time course of 239Pu resorption from the lungs to organs and tissues, first of all to the blood, especially at the early stage of metabolism (up to 1-3 days), are the basis for the optimization of a method of osseous tissue protection against the radionuclide by using competitive action of iron preparations.

[The effect of iron on the excretion by rats of intratracheally administered plutonium-239]. / Vliianie zheleza na ékskretsiiu u krys intratrakheal'no vvedennogo plutoniia-239.

A study was made of the effect of ferric citrate on excretion of intratracheally administered plutonium-239. The preparation used permitted to increase the radionuclide excretion via the gastrointestinal tract by 1.8 times as compared to the control. The positive effect of the iron preparation was maximally displayed between days 4 and 11 following administration: the value of the increase was 2.2.

[Determination of americium-241 in urine]. / Opredelenie ameritsiia-241 v moche.

A technique has been developed for the determination of americium 241 in urine by a radiochemical purification of the nuclide from uranium (upon co-precipitation of americium 241 with calcium and lanthanum), plutonium, thorium, and polonium 210 (upon co-precipitation of these radionuclides with zirconium iodate). alpha-Radioactivity was measured either in a thick layer of the americium 241 precipitate with a nonisotope carrier or in thin-layer preparations after electrolytic precipitation of americium 241 on a cathode.

[Possibility of a change in the parameters of plutonium-238 metabolism in the body]. / K voprosu o vozmozhnosti izmeneniia parametrov obmena plutoniia-23 8 v organizme.

The influence of macro amounts of iron on 238Pu metabolism in the animal body has been studied. The data obtained indicate that 238Pu metabolism parameters change under the effect of iron. The efficiency of the agent used is demonstrated by a diminished deposition of the radionuclide in bone tissues and an increased (by 2.65 times as compared with the control) excretion of plutonium 238 in faeces.

[Determination of the plutonium-239 content of the body]. / Ob opredelenii soderzhaniia plutoniia-239 v organizme.

In order to increase the informativeness of the indirect dosimetric estimates of plutonium-239 body levels complex makers are widely used to enhance natural excretion of the radionuclide in urine, the ratio between 239Pu levels in urine and skeleton being measured. However, as the onset of chelate application is postponed its efficacy, with respect to the skeleton, sharply decreases making it impossible to obtain reliable information concerning plutonium 239 levels in bone tissues at later times.

[Intensification of the excretory flow of plutonium-239 from the body in the late stage of its metabolism]. / Ob usilenii éksrektornogo potoka plutoniia-239 iz organizma na pozdnei stadii obmena.

The paper deals with the effect of iron preparations on the excretion of plutonium 239 from a body at a later stage of the radionuclide metabolism. The experimental results show that oral administration of the iron preparation at a later stage of 239Pu metabolism enhances the radionuclide excretion both in urine and in faeces. On the basis of the results obtained the coefficients are calculated for 239Pu excretion in urine and faeces and for its content in the organs of deposition. This may be used for increasing the sensitivity of indirect dosimetry of plutonium-239 within the body.

[Role of biocomponents of the bile and excreta in the elimination of plutonium and americium from the body]. / O roli razlichnykh biokomponentov zhelchi i ékskretov v protsessakh vyvedeniia plutoniia i ameritsiia iz organizma.

A study was made of the role of biocomponents of bile, urine and feces in the elimination of plutonium and americium from the organism. Plutonium 239 and americium 241 were separated in bile due to higher tropism of plutonium to low molecular weight ligands, and of americium, to a protein-containing fraction. The status of plutonium excreted in feces was the same as the physicochemical status of americium. Plutonium 239 and americium 241 eliminated in urine were in a completely ultrafiltered state.

[Plutonium-239 distribution in the body in relation to the rhythm of administration of an iron preparation]. / Raspredelenie plutoniia-239 v organizme v zavisimosti ot ritma vvedeniia preparata zheleza.

A study was made of the dependence of plutonium distribution among organs and tissues on the time of administration of iron preparation. Iron decreased the share of plutonium in bone tissues, somewhat increased it in soft tissues, and enhanced the excretion of the radionuclide from the organism. The protective efficiency of the preparation in relation to bone tissue was associated with the time of the administration thereof.

[Modification of 239Pu metabolism in the blood in various methods of iron preparation administration in the body]. / Modifikatsiia obmena 239Pu v krovi pri razlichnykh sposobakh vvedeniia preparata zheleza v organizm.

A study was made of the intravenous, intraperitoneal and oral routes of iron administration. It was shown that the oral route of the entry of appropriate amounts of iron in the body made it possible to saturate the transferrin spare capacity and hence to influence 239Pu metabolism in the blood. The results obtained can be employed for improving indirect dosimetry methods of 239Pu in the body using chelates.