New electrolytic enrichment system for tritium determination in water research institute in Bratislava and IT'S first results of tritium activity in precipitation.

The method of tritium activity measurements by electrolytic enrichment in combination with liquid scintillation counting is well known for many years. In the Water Research Institute in Bratislava was this system employed since the 60-ties of the 20th century. In 2018 the laboratory of radiochemistry of Water Research Institute obtained a new electrolytic enrichment system with higher enrichment factor (varying from 9 to 22, depending on the total ampere-hours used). The enrichment factor of the previous system was about 6. Complementary to the new system, also the new LCS counter Quantulus GCT 6220 was added. This spectrometer has active background suppression function (Guard Compensation Technology - GCT) and for the tritium measurement the background counts decreased from cca. 9 cpm (for Tricarb 2900 TR) to approximately 1 cpm. To demonstrate the capabilities of this system, we present results of the tritium concentration in precipitations during the period from May 2016 to May 2019. The seasonal variations of tritium activities in precipitation are observed, with maximum values in spring season and minimum in winter. Additionally, selected tritium activities from the extensive monitoring of river waters in Slovakia are presented.

Potential Source Apportionment and Meteorological Conditions Involved in Airborne 131I Detections in January/February 2017 in Europe.

Traces of particulate radioactive iodine (131I) were detected in the European atmosphere in January/February 2017. Concentrations of this nuclear fission product were very low, ranging 0.1 to 10 µBq m-3 except at one location in western Russia where they reached up to several mBq m-3. Detections have been reported continuously over an 8-week period by about 30 monitoring stations. We examine possible emission source apportionments and rank them considering their expected contribution in terms of orders of magnitude from typical routine releases: radiopharmaceutical production units > sewage sludge incinerators > nuclear power plants > spontaneous fission of uranium in soil. Inverse modeling simulations indicate that the widespread detections of 131I resulted from the combination of multiple source releases. Among them, those from radiopharmaceutical production units remain the most likely. One of them is located in Western Russia and its estimated source term complies with authorized limits. Other existing sources related to 131I use (medical purposes or sewage sludge incineration) can explain detections on a rather local scale. As an enhancing factor, the prevailing wintertime meteorological situations marked by strong temperature inversions led to poor dispersion conditions that resulted in higher concentrations exceeding usual detection limits in use within the informal Ring of Five (Ro5) monitoring network.

Anthropogenic 137Cs on atmospheric aerosols in Bratislava and around nuclear power plants in Slovakia.

Nuclear power plants (NPPs) have been one of the sources of anthropogenic radionuclides in the environment. This work combines the results from monitoring stations around NPPs in Slovakia (Mochovce and Jaslovské Bohunice) and academic measurements at the Comenius University campus in Bratislava. Most of the atmospheric 137Cs in this region come from the resuspension of the Chernobyl-derived 137Cs, as well as caesium produced during nuclear weapons testing. By comparison of the obtained results at NPPs with Bratislava data, radiation impacts of the NPPs on the local environments have been estimated to be negligible.

Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412).

The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.

Dispersion of Fukushima radionuclides in the global atmosphere and the ocean.

Large quantities of radionuclides were released in March-April 2011 during the accident of the Fukushima Dai-ichi Nuclear Power Plant to the atmosphere and the ocean. Atmospheric and marine modeling has been carried out to predict the dispersion of radionuclides worldwide, to compare the predicted and measured radionuclide concentrations, and to assess the impact of the accident on the environment. Atmospheric Lagrangian dispersion modeling was used to simulate the dispersion of (137)Cs over America and Europe. Global ocean circulation model was applied to predict the dispersion of (137)Cs in the Pacific Ocean. The measured and simulated (137)Cs concentrations in atmospheric aerosols and in seawater are compared with global fallout and the Chernobyl accident, which represent the main sources of the pre-Fukushima radionuclide background in the environment. The radionuclide concentrations in the atmosphere have been negligible when compared with the Chernobyl levels. The maximum (137)Cs concentration in surface waters of the open Pacific Ocean will be around 20 Bq/m(3). The plume will reach the US coast 4-5 y after the accident, however, the levels will be below 3 Bq/m(3). All the North Pacific Ocean will be labeled with Fukushima (137)Cs 10 y after the accident with concentration bellow 1 Bq/m(3).

Distributions of (137)Cs and (210)Pb in moss collected from Belarus and Slovakia.

In the present work, moss samples collected in Slovakia and Belarus were assayed with respect to gamma-emitting radionuclides. The results for (137)Cs and (210)Pb are discussed. Moss was used for the first time in Belarus, as a biological indicator of radioactive environmental pollution in consequence of the Chernobyl accident in 1986. In Belarus, the maximum activity of (137)Cs was observed in the Gomel region near Mazyr (6830 Bq/kg) and the minimum activity in the Vitebsyevsk Region near Luzhki-Yazno (5 Bq/kg). "Hot spots" were also observed near the towns Borisow and Yuratsishki. The results of measurements of (137)Cs in moss samples collected in 2000, 2006 and 2009 in the same localities of Slovakia are presented and compared with the results of air monitoring of (137)Cs carried out in Slovakia from 1977 until 2010. Measurements of the (210)Pb concentration in moss samples collected over the territory of Slovakia showed, that the median value exceed 2.3 times median value of (210)Pb obtained for Belarus moss. For that reason, the inhalation dose for man from (210)Pb and (137)Cs in Slovakia is more than twice as high as in Belarus, in spite of the initially very high (137)Cs exposure in the latter country.

Aerosol radioactivity record in Bratislava/Slovakia following the Fukushima accident--a comparison with global fallout and the Chernobyl accident.

Results of radioactivity measurements in Bratislava aerosols following the Fukushima accident showed that at least three radioactive plumes arrived to Bratislava as indicated by (131)I/(137)Cs activity ratios. When compared with the Chernobyl results available for the Bratislava station, the Fukushima radionuclide levels were almost five orders of magnitude lower, with the maximum values for (131)I and (137)Cs of 0.5 and 0.07 mBq/m(3), respectively. The (131)I and (137)Cs vs. (7)Be aerosol activity records showed that the increases in (131)I and (137)Cs activity concentrations were accompanied by (7)Be increases, indicating that both the horizontal and vertical transports of radionuclides were responsible for observed radionuclide concentrations. The (134)Cs/(137)Cs activity ratio was close to 1, as has also been reported by other investigators.

Long-term variations of 14C and 137Cs in the Bratislava air--implications of different atmospheric transport processes.

This study summarizes measurements of atmospheric (14)C and (137)Cs in the Bratislava air since 1976. Higher (14)C levels observed in spring and early summer months until the 1980's confirm injection of the stratospheric air into the troposphere. Later, deep winter minima were observed in (14)C concentrations, probably due to the depletion of the atmospheric (14)C levels in winter months by the injection of large quantities of fossil CO(2). Presently observed (14)C maxima in summer and minima in winter were caused by the depletion of the atmospheric (14)C in winter months, amplified by temperature inversions during winter, rather than by the injection of the stratospheric air into the troposphere. The observed (137)Cs activity concentrations also showed an impact of the stratospheric air on the (137)Cs levels until the early 1980's, documented by typical spring/early summer maxima and winter minima. The global fallout (137)Cs record was then disturbed by the Chernobyl accident (1986) when large quantities of (137)Cs were released to the atmosphere. The recent (137)Cs variations observed in the atmosphere, characterised by winter maxima and summer minima, are assumed to be mainly due to the resuspension of (137)Cs from the soil. A correlation was found between the (137)Cs activity concentration and the dust level in the air (the correlation coefficient r = 0.74), as well as an anticorrelation with the temperature (r = -0.56).

[Use of laboratory animals for toxicologic testing of drugs and chemicals]. / Pouzití laboratorních zvírat v toxikologickém testování léciv a chemikálií.

For evaluation of the possible risk of drugs and chemicals for the human organism and its vital functions and to detect possible undesirable action on the environment, laboratory animals must be used. In toxicology as biomodels standard strains, as regards genetic and health aspects, mice, rats, rabbits, guinea pigs and dogs are used. The basis of standardization of conditions for keeping laboratory animals is as regards physical, chemical and biological aspects adherence to conditions of the adopted regulations of the Council of European Communities of Nov. 24, 1986. Council Directive 86/609/EEC, known in this country as the "Strasbourg convention". Part of the protection of laboratory animals used for experimental and other scientific purposes is also the adherence to the optimal number of animals as regards the area or cage where they are kept as well as the cubic measure of the space. Standardization of scientific results is promoted also by adherence to transport conditions of the animals, the time of acclimatization, quarantine. Knowledge of the basic biology of laboratory animals used should be obvious for experimental workers. All work on animals must be governed by valid laws and instructions which make work with animals possible. In the Czech Republic its is the act of the Czech National Council No. 246 issued in 1992 for the protection of animals from maltreatment according to which work with animals can be carried out only by institutions with accreditation for the given work which moreover have an ethical commission which issues permission for work with animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparability of results of postnatal and long-term tests for carcinogenicity.

A method of testing postnatal carcinogenicity in rats was elaborated. The substances to be tested were administered from the 1st day after birth to the 5th, 10th and 20th days of age. The subsequent supply of a substance in diet from weaning (28th day of age) up to the end of the first year of survival was an optimal combination. A total of 12 substances were tested by this method. For all substances it was possible to provide a comparison with the results of long-term studies. For nine substances carcinogenicity was demonstrated in both tests, out of them in eight cases in identical organ systems. In three cases no carcinogenicity was ascertained in the postnatal study, in two compounds identical negative results were obtained by the two approaches. In one case (the cytostatic TS-160) development of sarcomas was found at the site of subcutaneous administration in the long-term study, and this effect was not observed in the postnatal study. Results identical for the two methods (carcinogenic or noncarcinogenic) were achieved in 11 substances, i.e. 91.7%. In addition, in 10 compounds, for which carcinogenicity was demonstrated either in the postnatal study or in the long-term study, the occurrence of tumors was found in identical organ systems after 8 compounds which is an 80% agreement. In mice, this identity of organs was demonstrated only in 62.5% of the compounds tested. The present results demonstrated that the use of postnatal carcinogenicity test in rats offers the determination of possible carcinogenic effect of the compound tested with a high probability, under economically more advantageous conditions, and with almost the same qualitative results as with the use of the long-term tests for carcinogenicity.

Trichlormethine hydrochloride and correlation of its mutagenic and toxic effects on male germ cells in mice.

The genetic effect of the cytostatic trichlormethine hydrochloride (TS-160 Spofa) was assessed after a 1-week administration using the dominant lethal mutation test (DLM) and the sperm abnormality test. The dosage was 0.5 mg/kg for 7 consecutive days, an equivalent of the human therapeutic dosage. Simultaneously, the cytostatic's direct toxic effect on male sex organs was assessed. TS-160 carries a genetic risk for the postmeiotic stages of spermatogenesis (DLM) and is responsible for interference in the morphology of sperm heads through its action on spermatocytes. The toxic effects of TS-160 were found to influence the body weight of mice (days 4-25 after administration), to reduce the relative weight of the testes (days 18-25 after administration), to damage spermatogenesis in the seminiferous tubules (spermatids), to be responsible for an appearance of multinucleate cells in the epididymides, and for an increased rate of abnormality of the heads of fully mature spermatozoa. Our findings stress the need to separate the cytotoxic effects from genetic effects so as to avoid false positives, especially in the test for head abnormalities, and also in the assessment of the fertility of male animals or fertilization of females mated with treated males.

Postnatal carcinogenic study of 1,2-dimethylhydrazine dihydrochloride in rats.

The outbred SPF rats of the Ripb: Wist stock were applied subcutaneously 1,2-dimethylhydrazine dihydrochloride (DMHD) at a concentration of 0.036% and 0.144% from the first day of age after the birth. In nine experimental groups DMHD was administered for first 5, 10, 15 and 20 days of age after the birth at total doses of 0.36 to 2.16 mg. With the highest applied dose, all animals died during the treatment, further deaths were recorded in groups in which DMHD was administered for first 5 to 10 days. The maximum length of survival was one year. The conclusion of the study was achieved only by the control animals and by 36.6% of males and 13.8% of females of the experimental group. From the 24th week of age, hepatic and renal tumors were detected in rats. In the liver hepatocellular carcinomas and benign hepatomas occurred, and were found in all groups which had been applied DMHD, furthermore cholangiomas, mostly in the groups which had been applied DMHD up to the age of 15 days and cavernomas in the groups which had been applied DMHD up to the age of 20 days. Practically in all rats which had been administered DMHD focal preneoplastic hyperplasia of liver cells was detected. In the kidney always a mixed malignant mesenchymal tumor was found in all animals of the groups treated up to age of 15 days.

Postnatal carcinogenic study of dimethylnitrosamine in rats.

Wist: Han/Pce SPF strain rats were administered dimethylnitrosamine (DMNA) in 0.04% concentration since the first day after birth. Total dose of 0.2 mg per infant rat was administered on 1st to 5th day of life, 0.4 mg/infant rat on 1st to 10th day and 0.5 mg on 1st to 20th day of life. Maximum survival time was one year. Both higher DMNA doses were already toxic the effect manifesting itself by increased mortality of the infant rats (liver hemorrhages, bleeding into the intestinal lumen) and reduced weight increment. Hepatic and renal tumors were detected in the rats beginning with their 19th week of life. In the liver they were hepatocellular carcinomas, to a lesser extent also cholangiomas and cavernomas. Further, increased incidence of preneoplastic nodular hyperplasia and benign hepatomas was demonstrated. In the kidney it was always the case of mixed mesenchymal tumor. Comparison of the results of postnatal study with a long-term carcinogenic DMNA study is discussed and possible reasons of different localization and characteristics of tumors dependent on DMNA administered were demonstrated.

[The effect of the non-antibiotic growth stimulators, Carbadox and Cyadox, on reproduction in laboratory animals]. / Ucinky neantibiotických stimulátoru rustu Karbadox a Cyadox na reprodukci laboratorních zvírat.

The effect of growth stimulators Carbadox and Cyadox was studied in laboratory rats and mice as exerted on their fertility, gravidity, embryo ontogenesis, and genetic efficacy of these drugs was also tested. In all tests one dose approaching the dose used in practice and multiple doses were administered. No antifertility effects were observed in either sex of rats, slight reduction in fertility was found in treated male mice. No teratogenic effect was observed, but both stimulators acted highly embryotoxically. Irrespective of the dose, genetic hazard occurred, influencing the first stages of spermatogenesis (spermatogony), and increasing the incidence ob abnormalities of spermatozoon heads after Carbadox treatment. In all tests Cyadox was less harmful than Carbadox. The results show that it is somewhat hazardous to use both growth stimulators in the period of animal reproduction.

Dominant-lethal test of 6-mercaptopurine: dependence on dosage, duration and route of administration.

A dominant-lethal test of 6-mercaptopurine (Spofa, CSSR) was carried out in male mice with four intraperitoneal, two oral, and one subcutaneous dosage levels. Furthermore, the drug was administered either in single doses or repeatedly for 7 and 14 consecutive days. With all of the dosage levels as well as administration durations and routes a genetic risk was proved at the periods of meiotic division and late premeiotic stages of spermatogenesis, manifested by increased percentages of fetal resorptions. In relationship to the total dose administered, irrespective of the route of administration, the most marked effect increasing the frequency of resorptions within the specified period of spermatogenesis was found in the groups that had received, by repeated administrations, more than 5.5 mg of 6-mercaptopurine per one male. Fertility reduction was apparent mainly after intraperitoneal injection; the differences were significant in weeks 3--5 of the test. The prenidation loss figures brought no univocal information about the interrelationship between the genetic effect and the stages of spermatogenesis.

Carcinogenicity of trichloromethine hydrochloride (TS-160 Spofa) and morphological damage after its intraamniotic injection.

The cytostatic TS-160 (trichloromethine hydrochloride, tris-/2-chloroethyl/amine hydrochloride) was injected subcutaneously into SPF Wistar rats of both sexes. After all doses used, spindle-cell or even polymorphocellular sarcomas developes at the injection sites in both sexes: after the dose of 0.1 mg/kg daily for 6 months, in 70%; after 0.25 mg/kg, in 79%; and after 1.0 mg/kg weekly for 6 months, in 45% of the rats. Besides, in 21% of the rats receiving the dosage of 0.25 mg/kg mucus-secreting intestinal adenocarcinomas were found. A relationship was apparent between the incidence figures of subcutaneous tumors on the one hand and the daily injection of the low dose versus the intermittent injection of the dose higher by a decimal order on the other hand. In a concurrent test, TS-160 was given to rats in intraamniotic injection on day 18 of pregnancy in doses of 1, 2.5, and 5 micrograms per embryo. On the first postnatal days, in the affected young rats there were observed morphogenetic disturbances: splanchnocrania and juvenile hair alopecia. These changes became repaired in the further course of postnatal development.

Absence of noxious effects of selected neuroleptics in dominant-lethal mutagenesis assay.

In a dominant-lethal assay in mice the following tricyclic neuroleptics were tested: prothiaden, imipramine, oxyprothepin decanoate and docloxythepin. No dominant-lethal effect was induced by these neuroleptics, even when administered at doses many times as great as clinical doses. The reduced percentages of pregnancies, in females who had copulated with males receiving docloxythepin, observed during and immediately after its administration, were directly connected with marked sedation induced in the males by this neuroleptic.