11 research outputs found

    Radon in air and water

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    Radon is a natural radioactive gas that you cannot see, smell, or taste and that can only be detected with special equipment. It is produced by the radioactive decay of radium, which in turn is derived from the radioactive decay of uranium. Uranium is found in small quantities in all soils and rocks, although the amount varies from place to place. Radon decays to form radioactive particles that can enter the body by inhalation. Inhalation of the short-lived decay products of radon has been linked to an increase in the risk of developing cancers of the respiratory tract, especially of the lungs. Breathing radon in the indoor air of homes contributes to about 15,000 lung cancer deaths each year in the United States and 1,100 in the UK (HPA 2009). Only smoking causes more lung cancer deaths

    From human niche construction to imperial power: long-term trends in ancient Iranian water systems

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    This article summarizes the outcome of a workshop sponsored by the Durham University Centre for Iranian Cultural Studies, where papers were presented on the entire chronological range of water management systems in Iran from around 8000 years bc until around 1000 ad. The primary aim was to recognize major research questions that could be used to create an agenda for future studies of ancient water use in the country. In the Durham meeting, it appeared that although the small-scale prehistoric systems probably constituted an example of ‘human niche construction’, the later imperial systems did not. Despite the recognition of occasional irrigation systems of third millennium bc date in the Deh Luran plain by Neely and Wright, as well as perhaps in Khuzestan, there appears to be a general dearth of evidence of Chalcolithic and Bronze Age systems in Iran. However, by the first millennium bc there was a considerable increase in the construction of major water management systems, some of which were, at least as far as the associated evidence suggests, constructed by imperial authorities. All agreed, however, that just because a system appeared large in scale, it was not necessarily a result of imperial management. For the subject of qanats it was argued that not only were they usually built by small-scale societies, but also that there may have been multiple centres of origin; one primary centre being a broad zone of south-east Iran, Pakistan and south-east Arabia

    Radon Levels in Romanian Caves: An Occupational Exposure Survey

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    A comprehensive radon survey has been carried out in seven caves located in the western half of Romania’s most significant karst regions. Touristic and non-touristic caves were investigated with the aim to provide a reliable distribution of their radon levels and evaluate the occupational exposure and associated effective doses. Radon gas concentrations were measured with long-term diffusion-type detectors during two consecutive seasons (warm and cold). All investigated caves exceed the European Union reference level of radon gas at workplaces (300 Bq/m3). The radon concentration in these caves ranges between 53 and 2866 Bq/m3, reflecting particular cave topography, season-related cave ventilation, and complex tectonic and geological settings surrounding each location. Relatively homogeneous high radon levels occur in all investigated touristic caves and in Tăuşoare and Vântului along their main galleries. Except for Muierii, in all the other caves radon levels are higher during the warm season, compared to the cold one. This suggests that natural cave ventilation largely controls the underground accumulation of radon. The results reported here reveal that the occupational exposure in Urşilor, Vadu Crişului, Tăuşoare, Vântului, and Muierii caves needs to be carefully monitored. The effective doses to workers vary between an average of 0.25 and 4.39 mSv/year depending on the measuring season. The highest values were recorded in show caves, ranging from 1.15 to 6.15 mSv/year, well above the European recommended limit, thus posing a potential health hazard upon cave guides, cavers, and scientists
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