Search

Terrestrial gamma radiation is mostly due to radionuclides in soil and rocks, primarily the 238U, 235U and 232Th radioactive families and 40K. This radiation contributes 15% to public exposure from all ionizing radiation sources, considering global population. Moreover, it can be used to estimate radon flux and included as one of the quantities relevant to the geogenic radon hazard model. Therefore, effort has been put into developing maps of terrestrial gamma dose rate at the regional, national or European scale, using different input data and methods. In the present work, two distinct approaches to map terrestrial gamma dose rate have been tested in the Euganean Hills district of NE Italy. The first one is based on 41 in situ measurements of ambient dose equivalent rates using a rate meter equipped with a NaI scintillator probe. The second one estimates terrestrial gamma dose rate from the U, Th and K activity concentrations in rock samples collected at the same locations of the dose rates measurements. The results obtained indicate good agreement between the two approaches, and as such suggest that the UNSCEAR 2008 prescription to derive ambient dose equivalent rate from laboratory gamma measurements produces reliable data, provided that cosmic and fall-out contributions are included. Moreover, the study proved that mapping the ambient dose equivalent rate (or terrestrial gamma dose rate) using only one database – i.e. either measured data or estimates derived from radionuclide activity concentration – yields valid results. [ABSTRACT FROM AUTHOR]

Abstract: We report on the first summer of high‐sensitivity radon measurements from a two‐filter detector at Jang Bogo Station (Terra Nova Bay) and contrast them with simultaneous observations at King Sejong Station (King George Island). King Sejong radon concentrations were characteristic of a marine baseline station (0.02–0.3 Bq m−3), whereas Jang Bogo values were highly variable (0.06–5.2 Bq m−3), mainly due to emissions from exposed coastal ground (estimated mean flux 0.09–0.11 atoms cm−2 s−1) and shallow atmospheric mixing depths. For wind speeds of ≤3.5 m s−1 the influence of local radon emissions became increasingly more prominent at both sites. A cluster analysis of back trajectories from King Sejong (62°S) revealed a fairly even distribution between air masses that had passed recently over South America, the Southern Ocean, and Antarctica, whereas at Jang Bogo (75°S) 80% of events had recently passed over the Ross Ice Shelf and West Antarctica, 12% were synoptically forced over Cape Adare, and 8% were associated with subsidence over the Antarctic interior and katabatic flow to the station. When cross‐checked against radon concentrations, only half of the back trajectories ending at Jang Bogo that had indicated distant contact with nonpolar southern hemisphere continents within the past 10 days showed actual signs of terrestrial influence. A simple‐to‐implement technique based on high‐pass filtered absolute humidity is developed to distinguish between predominantly katabatic, oceanic, and near‐coastal air masses for characterization of trace gas and aerosol measurements at coastal East Antarctic sites. [ABSTRACT FROM AUTHOR]

In road and railway tunnel excavation, personnel are exposed to natural radiation. Exposure can have varying degrees of significance, as naturally occurring radioactive material (NORM) content may vary by more than one order of magnitude depending on local lithology and, as far as radon is concerned, depending also on features of more distant bedrocks involved in radon convection. Radon exhalation and build up in the confined environment of the tunnel is affected by permeability of rocks, which is highly variable with lithology. Excavation methods as well have an impact on workers’ exposure, due both to exposure time and to protection afforded by the equipment. Therefore, it is of interest to develop a method to predict radon levels to characterize the work area. Since drill cores are invariably taken before excavation begins, for a preliminary assessment of the geology involved, a method is proposed here for predicting radon levels, based on NORM and exhalation measurements in drill core samples, and on the geometry of the tunnel to be excavated. An experimental campaign is under way on a railway tunnel under construction in northwestern Italy: preliminary results will be presented and predicted values compared to experimental measurements. [ABSTRACT FROM PUBLISHER]

Gamma radiation is a most efficient tool for sterilization, and especially effective on infesting pest, as it also kills the eggs. However, the large radiation doses entailed (tens of kilogray and up) might have adverse effects on desirable properties of wood. Of particular interest are the acoustic properties, as radiation would otherwise appear to be the perfect tool for the sterilization of musical instruments. The present investigation was aimed at determining the effects on acoustic and mechanical properties. Samples of four different wood species – poplar, oak, fir and maple – were prepared selecting wood completely free of visually detectable defects and subjected to incremental dose levels, reaching 25, 50, 100 and 200 kGy. A further set of samples were subjected to 200 kGy in one go, to investigate possible differences with incremental doses. Irradiation was conducted at an industrial irradiation facility, operating with a cobalt-60 source of the order of the megacurie. The mechanical tests were designed to measure the elastic modulus and the bending strength as well as force and displacement at rupture. Acoustic tests were developed specifically for this experiment, with the purpose of measuring the vibrational modes of the samples. All the samples exhibited discoloration and noticeable changes in properties: rigidity increased, load to rupture decreased, the material became more brittle and effects increased with increasing dose. The acoustic tests revealed a shift toward higher frequencies of all the vibrational modes, and this was exhibited for all wood species investigated. No meaningful difference was observed between the samples treated with incremental doses up to a total of 200 kGy and with a single 200 kGy dose. [ABSTRACT FROM PUBLISHER]

Abstract: Simultaneous measurements of airborne radionuclides 7Be and 210Pb, together with aerosol mass load PM10, have been routinely carried out at the Global WMO-GAW station of Mt. Cimone (Italy, 2165 m a.s.l., 44° 12′ N, 10° 42′ E) from 1998 to 2011. The experimental activity was started with the purpose of gaining a better understanding of the vertical and horizontal transports taking place at this site affecting the atmospheric chemical composition. The time series of the collected data is presented and discussed in this paper. The 7Be concentrations in this period are in the range 0.05–15.8 mBq m−3 with the presence of two distinct relative maxima during winter/spring and summer, suggesting an origin from different physical processes. The 210Pb concentrations collected during the period are in the range 0.05–2.30 mBq m−3 and are characterized by a single maximum during the warm period. The 7Be/210Pb ratio was in the range 0.5–127.8 and is characterized by a maximum during the cold period. The frequency distributions of the three parameters and the seasonal/interannual variabilities are investigated and presented. [Copyright &y& Elsevier]

Abstract: The paper analyzes PM10 data from Mt. Cimone observatory (44°11′ N, 10°42′ E) in the period 1998–2011. Mt. Cimone is the highest peak of the Italian northern Apennines (2165 m asl) which hosts a high altitude background station in Southern Europe. The dataset is discussed in the framework of the main atmospheric meteorological and territorial features, representative of the central Mediterranean free troposphere. The overall geometric mean of PM10 mass concentration in the period investigated is 6.0 μg m−3 (arithmetic mean 8.8 ± 8.0 μg m−3), with large variability at the synoptic time-scale. At Mt. Cimone station the PM10 mass load features a strong seasonal fluctuation with a winter minimum (0.1 μg m−3, average winter value: 4.1 ± 4.8 μg m−3) and a summer maximum (45.7 μg m−3, average summer value: 13.7 ± 7.2 μg m−3). Influence of surface source areas upon PM10 is discussed by comparison of simultaneous PM10 data collected at ground stations to the north and south of the Northern Apennine range in order to investigate transport connections at the regional scale. PM10 data collected from the Environmental Protection Agencies networks of Emilia Romagna and Tuscany mostly cover urban stations and a few rural and semirural stations usually at ground level. In general PM10 mass load exhibits a vertical negative gradient with altitude, with Mt. Cimone displaying the least average value. Nevertheless exceptions can be observed on an event basis, while direct comparison of concentration data is not advisable due to the remoteness of Mt. Cimone as compared even to rural or semirural stations. Analysis of PM10 time series in conjunction with fine and coarse particle number densities reveals the influence of transports from source regions such as the Northern African desert, the Po valley and the European continent including the Balkan area. Source apportionment of PM10 is achieved applying a methodology based on Hysplit back-trajectories calculation. [Copyright &y& Elsevier]

This work introduces an index to identify deep stratospheric intrusions (SI) from measurement data alone, without requiring additional model-based information. This stratospheric intrusion index (SI2) provides a qualitative description of SI event behaviour by summarizing the information from different tracer variations. Moreover, being independent from any model constraint, the SI2 can also represent a valid tool to help in evaluating the capacity of chemistry-transport and chemistry-climate models in simulating deep stratosphere to troposphere transport. The in situ variations of ozone, beryllium-7 and relative humidity were used to calculate the index. The SI2 was applied on 8-year data recorded at the regional GAW station of Mt. Cimone (2165 m asl; 44.10N, 10.70E: Italy). The comparison of the SI2 behaviour with a pre-existing database obtained by also using model products, permitted us to tune a SI2-threshold value capable of identifying SI events efficiently. In good agreement with previous climatological studies across Europe, at Mt. Cimone, the averaged monthly SI frequency obtained by the SI2 analysis showed a clear seasonal cycle with a winter maximum and a spring-summer minimum. These results suggest that the presented methodology is efficient for both identifying SI events and evaluating their annual frequency at the considered baseline measurement site. [ABSTRACT FROM AUTHOR]

The Ross Sea is an area of dense water formation within the Southern Ocean, hence it potentially plays an important role for anthropogenic CO2 sequestration. In order to estimate the penetration of anthropogenic carbon in the Ross Sea from total inorganic carbon (TC02) measurements carried out in 2002-03 Antarctic Italian Expedition, we applied two independent models. Anthropogenic carbon was present throughout the water column. The highest concentrations were associated with the recently ventilated shelf waters, namely High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), due to their recent contact with the atmosphere. The lowest concentrations were observed for Circumpolar Deep Water (CDW), due to its relatively older ventilation age. This water mass intrudes onto the shelf in some parts of the Ross Sea and hence is observed in the sampled section, where it is recognizable for its low O2 and high TCO2 concentrations. The overflow of the dense High Salinity Shelf Water out of the continental slope was observed in the area off Cape Adare. Since this recently formed shelf water contributes to the formation of the Antarctic Bottom Water (AABW), this process represents a pathway for anthropogenic carbon export down to the deep ocean. [ABSTRACT FROM AUTHOR]

A comparison between continuous lidar fluorosensor chlorophyll-a measurements and partial pressure of CO 2 ( p CO 2 ) in surface water is presented. The data were gathered during the XVI Italian Antarctic expedition in the Western Ross Sea and crossing the Southern Ocean. Anticorrelation between CO 2 levels and chlorophyll-a determinations was observed throughout the cruise in the late austral summer 2000/01. The survey revealed the presence of high productivity in polynya regions and close to the ice edges. The lidar data, reported here, are consistent with the results of previous campaigns conducted in the same investigated area. The relationship between p CO 2 and chlorophyll-a concentration are discussed in terms of biologically driven phenomena responsible for the p CO 2 undersaturation with respect to the atmospheric value during the austral summer. [ABSTRACT FROM AUTHOR]

Here we present the case of a 52-year-old woman with erythematous, scaly, non itching papules disposed unilaterally along the Blaschko's lines on the left side of the trunk, on the left arm and leg. This case, which shares histological and clinical characteristics with both lichen striatus and adult blaschkitis, should be included in the group of other diseases presenting with linear pattern and deined BLAISE (Blaschko-Linear Acquired Inlammatory Skin Eruption) by Taïeb et Al. (19) and more recently ABLD (Acquired Blaschko-Linear Dermatoses) by Keegan et Al. (10). [ABSTRACT FROM AUTHOR]

The contribution of 220 Rn is usually negligible compared to that of 222 Rn: its very short half-life makes escape from its source site within the rock very unlikely and it never has time enough to filtrate through the ground and through cracks in the floors or cellar walls to reach living quarters. This however becomes untrue if walls built with 232 Th-rich materials are present: then sizeable amounts of thoron may be detected in the closed areas bounded by those walls. This is the case for many dwellings in central Italy, and the town of Bolsena (northern Latium) is presented as a case study. A typical building of the area, entirely constructed with tuff blocks, is investigated and the annual dose rates calculated for varying distances from the wall. Thoron concentration was found to decrease with a relaxation length of 13 cm. Thoron was found to pose a significant risk. The rate of air exchange was found to produce little effect. Wall plastering acts as a filter: thoron diffuses through it but a HVL of less than 1 cm was found to prevail. [ABSTRACT FROM AUTHOR]