Long term 7Be deposition in Romania.

This study is based on monthly 7Be deposition data at 29 of the stations of Romania's National Environmental Radioactivity Surveillance Network (NERSN), with different geographical and climatological conditions, extending over periods up to 17 years (1979-1995). The 7Be activity in each monthly sample from each station was determined using high-resolution gamma-ray spectrometry performed at the Environmental Radioactivity Laboratory, Bucharest-Afumati. The annual dynamics of atmospheric deposition of 7Be at each NERSN station showed a strong seasonal trend, very similar to the precipitation regime, with the highest values being observed in spring/summer and the lowest in winter. But the annual 7Be deposition fluxes varied broadly from station to station and year to year, from a minimum of 164 Bq/m2/y (Bechet, 1989) to a maximum of 1388 Bq/m2/y (Baia Mare, 1988). This large space-time variability of deposition was mainly due to the variability of the precipitation regime. The analysis of experimental data confirms the strong correlation of 7Be deposition data with precipitation, air temperature and the number of sunspots. Wet and dry deposition data are presented and discussed for four stations where separate dry and wet 7Be deposition measurements were performed.

Marine radioactivity assessment of Mururoa and Fangataufa atolls.

The International Atomic Energy Agency (IAEA) carried out an international project. 'The Study of the Radiological Situation at the Atolls of Mururoa and Fangataufa' with the aim of assessing the present and future radiological situation at the atolls and making recommendations for either monitoring or remedial actions if they are deemed necessary. The paper concentrates on marine radioactivity aspects and gives an estimation of present radionuclide concentrations in water, sediment and biota of the Mururoa and Fangataufa lagoons and the surrounding ocean. The dominant radionuclide in both lagoons is Pu in sediments (the total inventory is approximately 30 TBq). A decline in radionuclide concentrations has been observed in recent years in lagoon water, with the exception of 3H and 90Sr, for which a contribution from underground sources is to be expected. Radionuclide concentrations in biota from the lagoons and the surrounding ocean are low and consistent with previous measurements. The observed radionuclide concentrations in both lagoons imply that no radiological risk exists for hypothetical inhabitants of Mururoa and Fangataufa Atolls.

Radionuclide concentrations in underground waters of Mururoa and Fangataufa Atolls.

In 1997 an expedition to Mururoa and Fangataufa Atolls was carried out to sample underground waters from cavity-chimneys and carbonate monitoring wells. The aim of this study was to determine the prevailing concentration and distribution status of radionuclides. Elemental analysis of interstitial waters was carried out in the water fraction as well as in particles collected at 11 underground monitoring wells. 238Pu, 239,240Pu, 241Am, 137Cs, 90Sr, 3H, 125Sb, 155Eu and 60Co were analyzed in both fractions by alpha-, beta- and gamma-spectrometry. Measurements showed that at 60% of the sites, pH and Eh seemed to be related to tidal cycles; in contrast HTO was constant during the sampling time. Interstitial waters from carbonates and transition zones shared similar chemical composition that were not different from that of the surrounding seawater. Waters collected from basalt cavities left after nuclear tests, (Aristee and Ceto) have a different chemical signature characterized by a deficiency in Mg, K and SO4 as well as enrichment in Sr, Si, Al and Cl compared to the rest of the stations. Radionuclide concentrations present in both, water and particulate fractions, were significantly higher at Ceto and Aristee than at any other monitoring wells, except for Fuseau and Mitre monitoring wells (Fangataufa) where values similar to Ceto were found (e.g. 239,240Pu: > 20 mBq g-1). Considering that Pu isotopes showed high Kd values compared to non-sorbing radionuclides such as 3H, 90Sr and 137Cs it is very unlikely that migration from cavities to monitoring wells accounts for the concentration of Pu isotopes and Am at Fuseau 30 and Mitre 27. Perhaps the contact of lagoon waters with the well before sealing could be a possible source of the transuranics found at these sites. The 238Pu/239,240Pu ratios measured in the particles were similar to that of the lagoon (0.38), thus supporting this hypothesis. The fact that transuranics were found only in the particle fraction, in the water (colloids included) these radionuclides were below detection limits, may be accounted for the conspicuous quantity of iron oxy-hydroxides present in the particulate fraction that under the appropriate redox conditions may be interacting selectively with elements in solution (scavenging) resulting in the enhanced transuranic signal. While transuranics have been found in places of their origin, radionuclides with low Kd values (3H, 90Sr, 137Cs) have already been transported to monitoring wells, as well as to the atolls' lagoons and the open ocean.

Studies on the familial character of endemic Balkan nephropathy. Possible role of the toxic hydric factor in the determination of "familial agglomerations" in endemic Balkan nephropathy.

The study was carried out in an attempt to explain the familial character of endemic Balkan nephropathy and of agglomeration of cases in certain households and in the ascendency of certain families. The hypotheses of a genetic disease or that of an infectious etiology have been taken into consideration in previous studies - by chromosomal analyses and statistical-mathematic tests of contagiousness - without being able to find arguments in support of one or the other hypotheses. This study brings important elements in favour of the possible role of ecologic factors and mainly of the hydrictoxic one, in the determination of the familial agglomerations in endemic nephropathy. Thus using radionuclear determination methods, we could demonstrate in a locality of the endemic area that around the water sources with high content of nephrotoxic oligoelements (cadmium, chromium, manganese, cobalt) there are more diseased families than around water sources poorer in these oligoelements.