Search results for " Radioactive"
showing 10 items of 47 documents
Radionuclides in wastewater treatment plants: monitoring of Sicilian plants.
2015
Three Sicilian wastewater treatment plants were monitored to assess the occurrence and the behaviour of radionuclides. Two sampling campaigns (screening and long-term) were carried out during which liquid and solid samples have been analysed. It was found that 131I mostly occurred in the samples analysed during the screening campaign (43% of the analysed samples contained 131I). High 131I specific activity was found in the mixed liquor, recycled sludge and dehydrated sludge samples. This finding was mainly due to the tendency of 131I to be associated with solid particles. During the long-term sampling campaign an influence of the sludge retention time (SRT) on the 131I behaviour was found. …
Experimental data collection and modelling of dry deposition velocities for urban surfaces
2018
Dry deposition process is recognized as an important pathway among the removal processes of radioactive pollutants in atmosphere. There is not a unique and accepted theoretical description of involved dry deposition phenomena due to the complexity of the fluid-dynamic processes that influence the deposition flux, but also because there is a lack of experimental data covering all scenarios of interest. In this paper, that is the result of a National Research Program a research activity conducted by DEIM Department of the University of Palermo and ENEA and funded by the Italian Minister of Economic Development, a new schema for parameterization of particle dry deposition velocity on urban are…
Analysis of Air Discharges from a PET Radiopharmaceuticals Production Center Based on a Cyclotron
2012
The control of air contamination in a Nuclear Medicine Center (NMC) provided with a cyclotron for the production of radiopharmaceuticals is based on an automatic systems for air sampling and measurements. An important control for the assessment of dose to the population is aimed at the measurement of air concentration of stack release and inside the cyclotron vault during irradiation. The frequency of sampling can be setup as continuous with respect to the stack effluent release and cyclic for other work environments. The gamma-ray spectrometric measurement are made on-line and for a short time by using a shielded Marinelli beaker filled with sampled air and a gamma detector. The use of thi…
Determination of 210Pb concentration in the air at ground-level by gamma-ray spectrometry
1999
Abstract 210 Pb activity concentrations in the air of Palermo were determined by γ-ray spectrometric analysis of 323 particulate samples collected in the period September 1995–December 1996. For each sample, the air filtered through a cellulose filter paper was 8600 m 3 on average. The values of the daily activity concentration of 210 Pb were ranging from 136 to 3390 μBq/m 3 .
Attività di interconfronto tra codici di trasporto atmosferico per la preparazione e la risposta alle emergenze nucleari
2019
In questo lavoro vengono presentati e confrontati i risultati ottenuti con tre differenti codici (FLEXPART, CALPUFF e ldX) per il trasporto atmosferico di inquinanti radioattivi. I codici vengono confrontati su una singola simulazione di un possibile rilascio incidentale alla stazione frontaliera di Gösgen (CH), in condizioni meteorologiche sfavorevoli per il territorio italiano. In this work we present and compare the results obtained iwth three different codes (FLEXPART, CALPUFF and ldX) for the atmospheric dispersion of radioactive pollutants. The codes are compared on a single simulation of a possible incident release in the Gösgen (CH) nuclear power plant with weather conditions that a…
Determination of extremely low (236)U/(238)U isotope ratios in environmental samples by sector-field inductively coupled plasma mass spectrometry usi…
2005
A method by inductively coupled plasma mass spectrometry (ICP-MS) was developed which allows the measurement of (236)U at concentration ranges down to 3 x 10(-14)g g(-1) and extremely low (236)U/(238)U isotope ratios in soil samples of 10(-7). By using the high-efficiency solution introduction system APEX in connection with a sector-field ICP-MS a sensitivity of more than 5,000 counts fg(-1) uranium was achieved. The use of an aerosol desolvating unit reduced the formation rate of uranium hydride ions UH(+)/U(+) down to a level of 10(-6). An abundance sensitivity of 3 x 10(-7) was observed for (236)U/(238)U isotope ratio measurements at mass resolution 4000. The detection limit for (236)U a…
Natural and artificial radioactivity levels in Livingston Island (Antarctic regions).
1994
Radioactive contamination of the sea and land is due, on the one hand, to fallout from atmospheric atomic explosions since 1945, and, on the other, to emissions produced by nuclear and radioactive facilities. Given its geographic position far distant from the aforementioned main sources of radioactive contamination, Antarctica should have the lowest levels that can be measured on the Earth of artificial radionuclides in the various receptor media which are characteristic of the trophic chain. In the case of Antarctica, these are melt-water, sea-water, mosses, algae, and lichens. With the aim of contributing basic information on the radiation levels present in the Antarctic ecosystem, we hav…
Groundwater radon measurements in the Mt. Etna area.
2003
Radon levels were measured in 119 groundwater samples collected throughout the active volcanic area of Mt. Etna by means of a portable Lucas-type scintillation chamber. The measured activity values range from 1.8 to 52.7 Bq l(-1). About 40% of the samples exceed the maximum contaminant level of 11 Bq l(-1) proposed by the USEPA in 1991. The highest radon levels are measured in the eastern sector of the volcano, which is the seismically most active zone of the volcano. On the contrary the south-western sector, which is both seismically active and a site of intense magmatic degassing, display lower radon levels. This is probably due to the formation of a free gas phase (oversaturation of CO(2…
Assessing the transfer of pentachlorophenol through soil columns using 13[C]isotope
2002
Abstract The transfer of organic pollutants was studied through soil columns using 13 [C]-labelled pentachlorophenol (PCP) as a model compound. The organic carbon content and the 13 [C]/ 12 [C] ratio were measured in two soil sections, 0–3 cm and 3–6 cm, and in percolated water using an Elemental Analyser coupled with a Magnetic Mass Sector. The mass balance of carbon was evaluated and the amount of PCP was calculated in each compartment of the soil–water systems. The results show that more than 80% of the PCP-derived 13 [C] remained in the upper layer of the soil column. Approximately 20% was transferred to the lower soil layer, and less than 1% was found in the water leachates. The 13 [C]…
Extensive Evaluation of a Diffusion Denuder Technique for the Quantification of Atmospheric Stable and Radioactive Molecular Iodine
2010
In this paper we present the evaluation and optimization of a new approach for the quantification of gaseous molecular iodine (I(2)) for laboratory- and field-based studies and its novel application for the measurement of radioactive molecular iodine. alpha-Cyclodextrin (alpha-CD) in combination with (129)I(-) is shown to be an effective denuder coating for the sampling of gaseous I(2) by the formation of an inclusion complex. The entrapped (127)I(2) together with the (129)I(-) spike in the coating is then released and derivatized to 4-iodo-N,N-dimethylaniline (4-I-DMA) for gas chromatography-mass spectrometry (GC-MS) analysis. The (127)I(2) collected can be differentiated from the (129)I(-…