Temporal evolution of 137Cs, 237Np, and 239+240Pu and estimated vertical 239+240Pu export in the northwestern Mediterranean Sea.

The evolution of 137Cs, 237Np and 239+240Pu at the DYFAMED station (NW Mediterranean) is discussed in relation to physical processes, downward fluxes of particles, and changes in the main input sources. The data set presented in this study represents the first complete 237Np vertical profiles (0.12-0.27µBqL-1), and constitutes a baseline measurement to assess future changes. A similar behavior of Cs and Np has been evidenced, confirming that Np behaves conservatively. While the 137Cs decrease has been driven by its radioactive decay, the vertical distribution of 237Np has not substantially changed over the last decade. In the absence of recent major inputs, a homogenization of their vertical distribution occurred, partly due to deep convection events that became more intense during the last decade. In contrast, 239+240Pu surface levels in the NW Mediterranean waters have fallen in the past four decades by a factor of 5. This decrease in surface has been balanced by higher concentrations in the deep-water layers. A first estimate of the downward 239+240Pu fluxes in the NW Mediterranean Sea is proposed over more than two decades. This estimation, based on the DYFAMED sediment trap time-series data and published 239+240Pu flux measurements, suggests that sinking particles have accounted for 60-90% of the upper layer (0-200m) Pu inventory loss over the period 1989-2013. The upper layer residence time of Pu is estimated to be ~28years, twice as long as the residence time estimated for the whole western Mediterranean (~15years). This difference highlights the slow removal of Pu in the open waters of the NW Mediterranean and confirms that most of the Pu removal occurs along the coastal margin where sedimentation rates are high.

A new Certified Reference Material for radionuclides in Irish sea sediment (IAEA-385).

A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.

Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea).

A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.

Impact of drug maintenance treatment on injection practices among French HIV-infected IDUs. The MANIF 2000 Study Group.

Drug maintenance treatment (DMT) has only been recently introduced in France (methadone programmes in March 1995, buprenorphine prescriptions in ambulatory medicine in February 1996) in relation to risk reduction policies for HIV infection among intravenous drug users (IDUs). Impact of DMT was assessed in the period of inclusion (October 1995-December 1997) of a French cohort of patients HIV infected through intravenous drug use the MANIF 2000 study). Among the 429 patients, 48.2% were ex-IDUs, 20.3% were active users not in DMT and 31.5% were in DMT. A majority (73.3%) of patients in DMT had persisted in their injection behaviours and their social and psychological characteristics were similar to those of active users not in DMT. Among the 186 active IDUs, those in DMT were more likely to have injected cocaine (42.4%) and buprenorphine or methadone (21.3%) than those who were not (respectively 27.6% and 2.4%), and 23.6% declared direct needle-sharing behaviours during the prior six months. Among younger IDUs (< or = 33 years of age) (n = 100), needle-sharing was associated with polydrug use and cocaine injection but was not significantly reduced by participation in DMT. These results suggest the need for taking into account differences between type of HIV-infected drug users and developing appropriate multidrug maintenance treatment programmes, which may imply adaptations of current dosages of methadone and buprenorphine.

Anthropogenic radionuclides in seawater of the Far Eastern Seas.

Large quantities of radioactive wastes have been dumped in the Far Eastern Seas by the former Soviet Union and the Russian Federation, and small amounts of radioactive wastes have been dumped by Japan and the Republic of Korea. In order to investigate the concentrations of anthropogenic radionuclides in the nine dumping areas, a second expedition was conducted in 1995 by Japan, the Republic of Korea, the Russian Federation and IAEA, following the first expedition in 1994. The results show that 137Cs, 90Sr and 239 + 240Pu concentrations in surface and bottom waters at dumping areas do not significantly differ from the values observed in background areas, and from historical values. There is no clear effect of possible contamination due to radioactive waste dumping. The concentrations and water column inventories of 137Cs, 90Sr and 239 + 240Pu in the Far Eastern seas are controlled by physical oceanic processes such as horizontal transport and biogeochemical processes such as scavenging.

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.

Isotope studies in the Caspian Sea.

Oceanographic and isotopic investigations in the Caspian Sea and the analyses of the available data on the discharge to the sea and the observed sea level changes suggest that climatically caused changes of river inflow are the major cause of the sea level fluctuations over the last century. Hydrogen-3 and 3H-3He data indicate that the deep basins of the sea are rapidly ventilated, although the hydraulic turnover time of the sea is approximately 200 years. The concentration levels of the anthropogenic radionuclides 90Sr, 137Cs and 239,240Pu in the water column can be explained by global fallout and therefore, at the sampling sites visited, there were no signs of dumping of radioactive wastes. The anthropogenic radionuclide data support the idea of fast exchange of water masses in the Caspian Sea. The isotopic and oceanographic data collected during the cruises have shown potential to allow for a better understanding of the water circulation in the Caspian Sea.

[Effect of halogenated quaternary ammonium on cultured tumor cells]. / Effet d'ammonium quaternaire halogéné sur des cultures de cellules tumorales.

This work reports the action of one halogenic quaternary ammonium compound on the in-vitro proliferation of different lines of human cancer cells. IC 50 inhibition growth was observed at a concentration of 2.10(-6) mol and T1 growth at 3.10(-6)-5.10(-5) mol. These results seem to indicate that halogenic quaternary ammoniums present a potent growth inhibitory activity on different cancer cells lines. The presence of a quaternary ammonium group, responsible for some alkylating effect, could explain such a result.

[Effect of chlorine-methylated quaternary ammonium on human gastric cancer cell proliferation]. / Effet sur la prolifération de cellules tumorales gastriques de sels d'ammonium quaternaires chlorurométhylés.

This work reports the action of some choline derivatives on the proliferation of the human gastric cancer cell line HGT-1 which does not secrete mucus or carcino-embryonic antigen, but express histamine H2 and somatostatin receptors. The structural family of the tested molecules (GMS-003F, GMS-005F et GMS-010F) belongs to the chloruro-methylated quaternary ammonium. A dose-dependent growth inhibitory effect, significant but weak (20%), was observed at 1-10 mM concentrations of GMS-003F, GMS-005F and choline. GMS-010F was more potent than the other derivatives to inhibit the growth of the cell line (IC50: 1 microM and total inhibition at 10 microM). Moreover, these compounds exert an effect on the membrane potential of this cell line, as measured by the capacity of membrane to concentrate fluorescent dyes (carbocyanines) in response to a membrane potential variation following the addition of a K+ ionophore, valinomycine: 10 mM GMS-005F or choline significantly reduced the fluorescence signal as compared to untreated cells. With GMS-010F, this effect was significant at concentrations as low as 0.1 microM and maximal at 1 microM. These results seem to indicate that the chemical series of the GMS-010F presents a potent growth inhibitory activity of a highly tumorigenic gastric cancer cell line. The presence of a quaternary ammonium group, responsible for some alkylating effect, could explain such a result.

Treatment of thymomas. A report of 67 cases.

From 1979 to 1989, 126 patients were treated for thymic tumors. Of these, 67 (53%) had thymomas occurring in 27 men and 40 women; the mean age was 46 years: 24 patients had no symptoms and myasthenia gravis was present in 21 cases. A complete resection was performed in 45 patients, associated in 22 with postoperative adjuvant treatment (radiotherapy, 2; radio- and chemotherapy, 20). Two patients had a partial resection followed by radiotherapy and chemotherapy. Twenty patients had initially only a biopsy and were treated by irradiation in 3 cases, radio- plus chemotherapy in 16, radio- plus chemotherapy and subsequent resection in 1 case. The staging was carried out according to the GETT Classification (stage I A:26; I B:6; II:12; III A:1; III B:18; IVA:4). Thymomas were found to be of predominant epithelial type in 12 cases, predominantly lymphocytic type in 9, and mixed in 46. No recurrence occurred after complete resection. The overall 10-year survival was 71.1%. A good correlation was found according to staging: 96% in stage I; 80% in stage II; 35% in stage III. Presence of myasthenia gravis did not affect the results. The best prognostic factor remains complete resection with postoperative radiotherapy to prevent recurrences. The role of adjuvant chemotherapy needs further evaluation.