scholarly journals Complementary measurements of radon concentration in water sources and natural exposure in dwellings in the vicinity of the Ramsar HLNRA, Iran

2012 ◽  
Vol 27 (4) ◽  
pp. 399-403 ◽  
Author(s):  
Mehrdad Amirzadi ◽  
Pooya Hosseini ◽  
Mehran Taheri ◽  
Asad Babakhani
Keyword(s):  
Radon Concentration ◽  
Diffusion Chamber ◽  
Water Sources ◽  
Frequency Distributions ◽  
Thermoluminescent Dosimeter ◽  
Natural Exposure ◽  
Radon Diffusion ◽  
Big City ◽  
High Level ◽  
Radon In Water

Tonekabon is a big city in the vicinity of the high level natural radiation area of Ramsar, Iran. Natural exposure due to gamma and radon concentration in 100 dwellings in the city has been measured using a thermoluminescent dosimeter and a radon diffusion chamber, respectively, over four seasons. Using active and passive methods (i. e. ZnS scintillation detectors and homemade radon diffusion chambers), the concentration of dissolved radon in water sources has been measured in both cities and frequency distributions of doses studied for radon measurements. Results show a daily average gamma dose of 4.2 ? 0.8 ?Sv and an average radon concentration in air of 232.5 ? 187 Bq/m3 in dwellings. Frequency distributions show that 85% of the dwellings have an average radon concentration of 100 to 300 Bq/m3 per year and that 80% have a maximum seasonal radon concentration of up to 400 Bq/m3. The maximum concentrations of dissolved radon in water in Ramsar and Tonekabon have been measured as 198 ? 30 and 109 ? 16 BqL-1, respectively.

EVALUATION OF RADON CONCENTRATION IN IRRIGATION AND DRINKING WATERS FROM THE EASTERN PART OF OMAN AND ESTIMATION OF EFFECTIVE DOSES TO OMANIS

2019 ◽  
Vol 184 (3-4) ◽  
pp. 422-425 ◽  
Author(s):  
S M Nasser ◽  
M U Khandaker ◽  
D A Bradley ◽  
M O Isinkaye
Keyword(s):  
Radon Concentration ◽  
Water Quality Assessment ◽  
Optical Microscope ◽  
Water Sources ◽  
Drinking Waters ◽  
The Us ◽  
Us Epa ◽  
Effective Doses ◽  
Radon In Water ◽  
Irrigation Waters

Abstract The present study concerns measurement of the radon concentration in drinking and irrigation waters obtained from the eastern part of Oman, in particular in regard to water quality assessment of the region. The samples were collected from different places covering most types of water sources in the region. A passive and time-integrated track etch detector (LR-115 type II) combined with a high-resolution optical microscope has been used to obtain the radon concentration in the studied samples. Values of dissolved radon in water varied among the water sources; the highest concentration of radon was found to be 363 Bq m−3 in a drinking water sample while well water used for irrigation showed the lowest value, at 140 Bq m−3. Measured data for all water sources are below the permissible limit of 11.1 kBq m−3 recommended by the US-EPA. Annual effective doses for the studied samples were in the range 0.38–0.99 μSv y−1 which is significantly less than the action level recommended by the WHO (0.1 mSv y−1), indicating that the water sources in the Jalan BBH region of Oman are safe to use. The obtained data may serve as a reference for any future radiological study of the waterbody of this region.

Heritability of the Effect of Corticosteroids on Intraocular Pressure

1970 ◽  
Vol 19 (1-2) ◽  
pp. 264-267 ◽  
Author(s):  
F.H. Reuling ◽  
J.T. Schwartz
Keyword(s):  
Intraocular Pressure ◽  
Clinical Signs ◽  
Topical Steroids ◽  
Frequency Distributions ◽  
Steroid Response ◽  
Large Numbers ◽  
Wide Range ◽  
Allele Pair ◽  
High Level ◽  
Genetically Determined

In the late 1950's and early 1960's, it became evident that some glaucoma patients developed elevations of intraocular pressure, which were difficult to control, following prolonged use of systemic or ocular medications containing corticosteroids (Chandler, 1955, Alfano, 1963; Armaly, 1963). In addition, some patients without glaucoma, when treated with steroids for long periods of time, developed clinical signs of chronic simple glaucoma (McLean, 1950; François, 1954; Covell, 1958; Linner, 1959; Goldman, 1962). Fortunately, the elevation of intraocular pressure was reversible if the drug was discontinued.Over the past decade, extensive investigation of the “steroid response” has been undertaken. For this presentation, the steroid response may be considered as a gradual elevation of intraocular pressure, occurring over several weeks, in an eye being medicated with corticosteroid drops several times a day. The elevation in pressure is usually accompanied by a reduction in the facility of aqueous outflow. When relatively large numbers of subjects were tested with topical steroids, so that a wide range of responsiveness could be observed, a variation in individual sensitivity was demonstrated. Frequency distributions of intraocular pressure or change in pressure following steroids showed a skew toward the high side. On the basis of trimodal characteristics which they observed in such frequency distributions, Becker and Hahn (1964), Becker (1965) and Armaly (1965, 1966) considered the possible existence of several genetically determined subpopulations. These investigators distinguished three subpopulations on the basis of low, intermediate, and high levels of pressure response. It was hypothesized that these levels of response characterized three phenotypes, corresponding to the three possible genotypes of an allele pair, wherein one member of the pair determined a low level of response, and the other member determined a high level of response (Armaly, 1967).

Alpha track distribution on lateral wall of cylindrical radon diffusion chamber

2021 ◽  
pp. 109873
Author(s):  
V.M. Markovic ◽  
J.M. Stajic ◽  
B. Milenkovic ◽  
N. Stevanovic
Keyword(s):  
Lateral Wall ◽  
Diffusion Chamber ◽  
Radon Diffusion

CONTINUOUS RADON-IN-WATER MONITORING—COMPARISON OF METHODS UNDER LABORATORY CONDITIONS AND RESULTS OF IN SITU MEASUREMENTS

2019 ◽  
Vol 186 (2-3) ◽  
pp. 406-412
Author(s):  
Petra Vyletělová ◽  
Aleš Froňka
Keyword(s):  
Response Time ◽  
Detection System ◽  
Response Delay ◽  
Detection Systems ◽  
Water Detection ◽  
Radon Diffusion ◽  
Flow Through ◽  
Continuous Monitor ◽  
Radon In Water

Abstract The extraction of dissolved radon from water to gas is the most common way to measure radon concentration in water continuously. The response delay of continuous radon-in-water detection system (continuous monitor + equilibrator) is influenced by the response time of the continuous monitor and a rate of an establishment of equilibrium in the equilibrator (exchanger unit). Two types of equilibrators were used in performed experiments to compare the response time of various detection systems—RAD AQUA that uses water spraying and equilibrator with ACCUREL® PP membrane that enables radon diffusion. Each of these was connected to the continuous monitor RAD7 or RM-3. The response delay after turning on the water flow through the equilibrator was determined. The fastest detection system was RAD7 + RAD AQUA that was subsequently tested during the insitu measurement of thermal water in the healing spa and water sources near Cheb and České Budějovice.

STUDY ON RADON CONCENTRATION VARIATION DURING SUBWAY CONSTRUCTION

2020 ◽  
Vol 191 (4) ◽  
pp. 409-422
Author(s):  
Bo Tan ◽  
Guangyuan Yang ◽  
Shuhui Fu ◽  
Cheng Xu
Keyword(s):  
Ambient Temperature ◽  
Radon Concentration ◽  
Comprehensive Analysis ◽  
Subway Station ◽  
Underground Space ◽  
Measuring Point ◽  
Low Level ◽  
Subway Construction ◽  
Under Construction ◽  
High Level

Abstract The high radon concentration in the underground space of the subway station during construction often endangers the health of workers. Subway station project No. 16 in Beijing, while under construction, was selected as the main measuring point, a year’s monitoring data was obtained to analyse the change of radon concentration. It was found that the concentration of radon was basically within the range of 5 ~ 500 Bq/m3 and showing a low level in the morning and a high level at noon, and presents the seasonal rule, compared with other seasons, the summer radiation is stronger. Furthermore, among the different measuring points, the radon concentration of the heading roadway is the highest, and the construction level of the station hall is the lowest. According to the comprehensive analysis, the concentration of radon during the construction of the subway station is mainly affected by the ambient temperature and air mobility.

Fungi with heteroxenous life histories

1995 ◽  
Vol 73 (S1) ◽  
pp. 1334-1342 ◽  
Author(s):  
David Malloch
Keyword(s):  
Reproductive Success ◽  
Life Histories ◽  
Transmission Efficiency ◽  
Lifetime Reproductive Success ◽  
Population Densities ◽  
Frequency Distributions ◽  
Parasitic Fungi ◽  
Host Life ◽  
High Level ◽  
Dispersal Events

Heteroxenous (multiple host) life histories are characteristic of many groups of parasitic protista and animals, including Zoomastigina, Apicomplexa, Mesozoa, Platyhelminthes, Nematoda, Acanthocephala, Pentastomida, and Arthropoda. Parasitic fungi, including the Chytridiomycota and the Dikaryomycota (ascomycetes and basidiomycetes), may also have heteroxenous life histories and have many features in common with parasites from other groups. In spite of many conceptual similarities, the study of parasitic fungi has occurred in isolation, resulting in the creation of a separate vocabulary and literature. Many of the concepts developed by zoologists are useful to mycologists and allow examination of parasitic fungi from new perspectives. These new perspectives reveal that heteroxenous fungi are not only similar to heteroxenous protistans and animals but that they also have unique characteristics of their own. Chief among these is a high level of endocyclic asexual reproduction, a phenomenon promoting exponential increases of infections in definitive host populations. Heteroxeny appears to have a number of benefits including (i) increased lifetime reproductive success, (ii) increased transmission efficiency (iii) enhanced effectiveness in colonizing ephemeral or periodically appearing hosts and hosts occurring in low population densities, (iv) maintenance or enhancement of overdispersed frequency distributions in host populations, and (v) enhancement of genetic exchange through multiple dispersal events. Key words: fungi, heteroxenous, parasite, life histories.

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