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1.
P. F. Hudak 《Environmental Geology》1996,28(1):29-33
The purpose of this study was to compare regional patterns of indoor radon concentration with uranium-bearing rock zones
and county populations in Texas. Zones yielding radon concentrations that are relatively high for Texas include shale and
sandstone in northwest Texas; red beds in north-central Texas; felsic volcanic rocks in west Texas; and sandstone, limestone,
and igneous rocks in central Texas. Located in northwest Texas, only five of the 202 counties evaluated have mean indoor radon
concentrations above 4.0 pCi l–1. Two of those counties have populations above the state median of 20 115. The highest county mean concentration is 8.8 pCi l–1. Results of this study suggest that (1) regional geology influences indoor radon concentrations in Texas, (2) statewide,
the radon concentrations are relatively low, (3) highly populated counties do not coincide with regions of high indoor radon
concentration, and (4) regions that may warrant further monitoring include northwest Texas and, to a lesser degree, west and
central Texas.
Received: 8 August 1995 · Accepted: 6 September 1995 相似文献
2.
A 3-year study of indoor radon in more than 1000 homes in northern Virginia and southern Maryland was conducted using 3-month
exposure alpha-track monitors. In a study set of 200 homes, first-floor indoor radon concentrations, which most closely approximates
home exposure levels, averaged slightly more than 3 pCi/l. In a study set of 100 homes, sub-slab ventilation was used to reduce
indoor radon concentrations. Interest in remediation was related to public perception of the hazardous nature of radon; people
living in homes with indoor radon measurements of more than 4 pCi/l were more likely to participate in the remediation phase
of the project. Sub-slab ventilation was successful in more than 90% of the homes in reducing indoor radon from concentrations
as high as 30 pCi/ to less than 4 pCi/l, at least for the entire year of post-remediation radon measurements.
Received: 29 February 1996 · Accepted: 29 May 1996 相似文献
3.
The radon-222 (222Rn) activity in groundwater of the Apulian karstic aquifer in southern Italy is as great as 500 Becquerel per liter (Bq/L)
locally. Normal radium-226 (226Ra) activity in the limestone and calcareous dolomites of the aquifer is not enough to explain such a high level. Laboratory
investigations identified high 226Ra activity in the "terra rossa," the residuum occupying fissures and cavities in the bedrock, and also the relation between
(1) 226Ra-bearing bedrock and "terra rossa" and (2) 222Rn in water. The "terra rossa" is the primary source of the radon in the groundwater. The experimental results show the need
to characterize the "terra rossa" of Apulia on the basis of 226Ra activity and also to study the distribution and variations in 222Rn activity over time in the aquifer.
Received, January 1996 · Revised, March 1997, September 1997, June 1998 · Accepted, July 1998 相似文献
4.
A comparison of geochemical information obtained from two fluvial bed sediment fractions 总被引:3,自引:1,他引:3
Ross. A. Sutherland 《Environmental Geology》2000,39(3-4):330-341
A total of 121 bed sediment samples were collected from a 5.8-km stretch of Manoa Stream, Hawaii. Samples were physically
partitioned into two grain-size fractions, <63 μm and 63–125 μm, acid digested and analyzed by ICP-AES and FAAS. Non-parametric
matched-pair statistical testing and correlation analysis were used to assess differences and strengths of association between
the two fractions for Al, Ba, Cu, Fe, Mn, Ni, Pb, Ti and Zn. Results indicated statistically significant differences between
fractions for all elements except Mn. Concentrations were significantly greater in the <63 μm fraction for Al, Cu, Pb, Ti
and Zn, while Ba, Fe and Ni were higher in the 63–125 μm fraction. Though some elements had statistically significant differences
between fractions (Al, Ba, Fe and Zn) percentage differences were in the range of analytical precision of the instrument and
thus differences were not practically significant. Correlation analysis indicated strong positive associations for all elements
between the two fractions (p<0.0001). Three contamination indices indicated similar degrees of pollution for each size fraction
for four elements having an anthropogenic signal (Ba, Cu, Pb and Zn). The environmental information obtained from the 63–125 μm
fraction was essentially equivalent to that from the <63 μm fraction. In this system it is clear that both bed sediment fractions
indicate anthropogenic enrichment of trace metals, especially Pb, and further supports previous research that has found that
aquatic sediments are critical median for tracing sources of pollution.
Received: 17 August 1998 · Accepted: 30 October 1998 相似文献
5.
From radon hazard to risk prediction-based on geological maps,soil gas and indoor measurements in Germany 总被引:3,自引:0,他引:3
Mapped geological units can be regarded as proxies standing for a complex series of subsoil geochemical and physical properties
including the assigned radon activity concentration in soil gas, which is taken as best estimator of the regional geogenic
radon potential. Areal distribution of measuring sites for soil gas in Germany is adapted to spatial variation of geology.
A grid-based and distance-weighted interpolation procedure is applied, following geologically defined neighbourhood relations
of measuring sites and accounting for isolated outcrops of known geology but without measurements. To investigate the statistical
relationship between indoor radon, house type and building ground specifications, measurements of the indoor radon concentration
have been carried out in more than 10,000 dwellings in different regions of Germany. Multiple regression analyses of variance
reveal that besides region-specific geological properties and building characteristics, various house type and living style
variables significantly contribute to the explained variance for ground floor radon concentrations. These parameters are also
dominant in controlling the radon transfer relation from soil gas to indoor air. Risk prediction maps for radon in houses
indicating the probability to exceed certain indoor threshold values can be useful especially for regions with no or only
a few measurements of indoor radon. 相似文献
6.
L. G. Kodosky 《Environmental Geology》1994,23(1):65-72
Analysis of 153 residential air radon (Rn-222) screening measurements from southeast Michigan indicates that basements host Rn levels two to three times higher than upper-level rooms. Compared to unfinished basements, finished (e.g., paneled walls, tiled floors) basements apparently reduce indoor air Rn levels while partially finished basements may not. Factor analysis of residence questionnaire data explains 59 percent of the Rn data variance. The volume of pathways (e.g., foundation cracks/holes, uncapped sumps) allowing Rn seepage into the dwelling controls the largest portion, 23 percent, of the explained data variance. The residence water source explains 11 percent of the Rn data variance. Groundwater Rn levels contribute to the air Rn data variability, but the study data cannot quantitatively assess this contribution. Seven percent of the Rn data variance is likely controlled by house depressurization facilitated by residence structural properties. Residences with foundation cracks or poorly sealed joints and low-volume indoor-outdoor air exchange are more prone to this effect. Eighteen percent of the explained Rn data variance correlates with the residence's primary heat source. Evidently, operating combustion sources also induce house depressurization and allow Rn to be drawn into the house through entry paths. Twenty-four percent of the analyses equal or exceed 4 pCi/1 Rn. In residences occupied 5 years by the same individuals, 17 percent of the Rn data are 4 pCi/l; here the arithmetic mean air Rn level is 8.3 pCi/l and the average occupancy period 17.4 years. 相似文献
7.
E. Tóth F. Deak C. S. Gyurkócza Z. S. Kasztovszky R. Kuczi G. Marx B. Nagy S. Oberstedt L. Sajó-Bohus C. S. Sükösd G. Toth N. Vajda 《Environmental Geology》1997,31(1-2):123-127
A steady radon exhalation is assumed in most publications. In a village of North-East Hungary, however, high radon concentrations
have been measured, differing strongly in neighbouring houses and varying in time, due to the interplay of geochemical phenomena.
Received: 20 November 1995 · Accepted: 18 June 1996 相似文献
8.
Radon in Himalayan springs: a geohydrological control 总被引:3,自引:0,他引:3
This paper presents the results of radon measurements in springs of the Himalayan region by using radon emanometry technique.
The radon was measured in different springs, draining from different geohydrological setups, and from stream water in order
to find the geohydrological control over radon concentration in groundwater emanating in the form of spring. The radon values
were found to vary from 0.4 Bq/l to 887 Bq/l, being observed lowest for a turbulent stream and highest for the spring. The
radon values were recorded highest in the springs draining through gneiss, granite, mylonite, etc. Radon concentrations have
been related with four spring types viz. fracture-joint related spring, fault-lineament related spring, fluvial related spring
and colluvial related spring, showing geohydrological characteristics of the rocks through which they are emanating. The high
radon concentration in fracture-joint and fault-lineament spring is related to increased ratio of rock surface area to water
volume and uranium mineralisation in the shear zones present in the close vicinity of fault and thrust. The low concentration
of radon in fluvial and colluvial springs is possibly because of high transmissivity and turbulent flow within such deposits
leading to natural de-emanation of gases.
Received: 6 January 1998 · Accepted 11 May 1999 相似文献
9.
A. Rimi 《International Journal of Earth Sciences》1999,88(3):458-466
Thermal and deep seismic soundings data are used to study the dependence between the compressional Pn velocity and the surface heat flow or the temperature at the Moho discontinuity in Morocco. This correlation indicates a
significant decrease in Pn velocity where high heat flow and Moho temperature are observed. This result is consistent with respect to other regions
of the world. Crustal heat generation models and geotherms are constructed for the major Moroccan geological domains extending
from the Precambrian units in the south to the Alpine units in the north. The crustal contribution in surface heat flow is
on average 35 mWm–2, with high values of 41–42 mWm–2 in the western and eastern Meseta where Hercynian granite intrusions could enrich the crust in radioactive heat sources.
High mantle heat flow values are obtained beneath the Alboran neogene basin (62 mWm–2), the Rif (47 mWm–2), the Middle Atlas (41 mWm–2), and the south Atlantic margin (40 mWm–2) where the crust is thinned by an extensional tectonic regime. Despite their similar formation context, the intra-continental
belts of the Middle and the High Atlas show different geothermal field components. A lithospheric heating process in the Middle
Atlas could be the result of a Plio-Quaternary basaltic volcanism. Finally, the Precambrian basement of the Anti-Atlas like
all the West African shield is a stable domain showing the lowest subsurface temperatures.
Received: 14 January 1998 / Accepted: 29 June 1999 相似文献
10.
Groundwater as a geologic agent: An overview of the causes, processes, and manifestations 总被引:29,自引:4,他引:25
József Tóth 《Hydrogeology Journal》1999,7(1):1-14
The objective of the present paper is to show that groundwater is a general geologic agent. This perception could not, and
did not, evolve until the system nature of basinal groundwater flow and its properties, geometries, and controlling factors
became recognized and understood through the 1960s and 1970s.
The two fundamental causes for groundwater's active role in nature are its ability to interact with the ambient environment
and the systematized spatial distribution of its flow. Interaction and flow occur simultaneously at all scales of space and
time, although at correspondingly varying rates and intensities. Thus, effects of groundwater flow are created from the land
surface to the greatest depths of the porous parts of the Earth's crust, and from a day's length through geologic times. Three
main types of interaction between groundwater and environment are identified in this paper, with several special processes
for each one, namely: (1) Chemical interaction, with processes of dissolution, hydration, hydrolysis, oxidation-reduction,
attack by acids, chemical precipitation, base exchange, sulfate reduction, concentration, and ultrafiltration or osmosis;
(2) Physical interaction, with processes of lubrication and pore-pressure modification; and (3) Kinetic interaction, with
the transport processes of water, aqueous and nonaqueous matter, and heat. Owing to the transporting ability and spatial patterns
of basinal flow, the effects of interaction are cumulative and distributed according to the geometries of the flow systems.
The number and diversity of natural phenomena that are generated by groundwater flow are almost unlimited, due to the fact
that the relatively few basic types are modified by some or all of the three components of the hydrogeologic environment:
topography, geology, and climate. The six basic groups into which manifestations of groundwater flow have been divided are:
(1) Hydrology and hydraulics; (2) Chemistry and mineralogy; (3) Vegetation; (4) Soil and rock mechanics; (5) Geomorphology;
and (6) Transport and accumulation. Based on such a diversity of effects and manifestations, it is concluded that groundwater
is a general geologic agent.
Received, December 1998 · Revised, January 1999 · Accepted, January 1999 相似文献
11.
Using a large database of residential short-term radon measurements in New Hampshire, this study evaluated the ability of expert-assigned bedrock radon potential for predicting residential radon concentration. First, each bedrock type was assigned a radon potential level by a geologist familiar with the local geology. Then, using residential radon measurements, a continuous surface of radon concentration was generated through a kriging process. The mean residential radon concentration within the spatial extent of each bedrock type was then calculated based on that surface. The Spearman Rank Correlation Coefficient was calculated between the two ranks of the bedrock types, one based on the expert-assigned potential level and the other based on the mean residential concentration. A strong correlation between the rank correlation and the area of the bedrock type was found. When only the 15 largest bedrock types were used, the Spearman Correlation Coefficient reached 0.6. Geological knowledge is concluded to be useful in predicting and mapping residential radon concentration, but the prediction should be interpreted with caution, especially for areas in which the underlying bedrocks are highly localized. 相似文献
12.
Background concentrations of heavy metals in aquatic bryophytes used for biomonitoring in basaltic areas (a case study from central France) 总被引:1,自引:0,他引:1
Studies were made of the aquatic bryophytes Fontinalis antipyretica Hedw., Platyhypnidium rusciforme (Neck.)Fleisch and Chiloscyphus sp. (Hoffm.)Dum. from streams embedded in basaltic rocks (Le Puy, central France). Water from these streams possessed elevated
levels of Cu, Zn, Sr, V, Ba, Ni and Co, reflecting the geochemistry of the basalts, a basic type of igneous rocks containing
elevated levels of these elements. The concentration of elements in bryophytes is correlated to the chemical composition of
water of their sampling sites. Contents of trace elements in plants were higher than background values. The elevated levels
of these elements possibly caused disturbances in the ionic equilibrium within the bryophytes. The molar ratio between contents
of Ca and Mg in water (from 0.44 to 1) was different from that typical for natural water.
Received: 16 September 1998 · Accepted: 17 December 1998 相似文献
13.
In the spring of 1995, 24 samples were collected from a widely distributed system of municipal water wells in Albuquerque, N.M., and analyzed for hydrogen (δD) and oxygen (δ18O) isotopic compositions. δD values for 15 of these samples are largely similar to those reported by Yapp in 1985, but have locally become more negative by as much as 5 per mil (ö). δD–δ18O data define two endmembers that are well aligned along the familiar meteoric water line (MWL): (1) the eastern domain (mountain precipitation runoff), having δD>–86ö (similar to the criteria of Yapp) and δ18O>–12.1ö (this work); and (2) a central basin domain, which may be in part derived from water seepage from the Rio Grande, having δD<–95ö and δ18O<–13.2ö. Only a few wells across the basin have δD values near the "baseline" value of the Rio Grande, defined by Yapp as –92ö. The proximity of these wells to the Rio Grande is consistent with recharge by seepage from the river bed under baseline conditions. Extensive pumping in the eastern domain and West Mesa areas may be partly responsible for an apparent expansion of the central-basin regime of water more depleted in δD, much as a plume migrating in response to transient perturbations in original hydraulic gradients. Vertically stacked groundwater occurrences having limited interconnection are inferred from the significant differences in isotopic compositions of samples from two wells screened at multiple depths. The central and western parts of the basin are little influenced by contributions from the eastern domain. Some groundwaters from the western part of the basin plot below the MWL and clearly cannot be mixtures solely of the eastern domain and central basin endmembers. The origins of these western groundwaters and the most depleted central basin groundwaters are as yet unknown, but we speculate they may have received recharge under climatic conditions different from the present. 相似文献
14.
Tadeusz Andrzej Przylibski Krystian Mroczkowski Adam Zebrowski Paweł Filbier 《Environmental Geology》2001,40(4-5):429-439
Radon is a significant component of the groundwaters that discharge in the springs of Szczawno Zdrój and are recognized as
medicinal. However, among the five exploited springs adjoining each other, it is only in Marta Spring that radon occurs in
large concentrations (up to 325.6 Bq/dm3). Therefore, the authors have made an attempt to describe and clarify this fact. They found out from their own research and
archival data that 222Rn dissolves in the waters of Marta Spring after acidulous waters of deep circulation have mixed with poorly mineralized shallow
waters in their outflow zone. The genesis of the gas is determined by the content of its parent nuclide, 226Ra, in the sandstones in the vicinity of the intake. The volume of the rocks providing radon to the waters of this intake
has been estimated at several hundred cubic metres. No seasonal fluctuations in radon concentration have been observed and
222Rn concentration changes do not seem to be influenced by changes in the concentration of other chemical components of the
waters or by the discharge of the intake. The process of dissolving 222Rn in the medicinal groundwaters of Marta Spring is the last, the shortest, and the most local of the processes that form
the chemical composition and the physical properties of these waters.
Received: 7 January 2000 · Accepted: 12 August 2000 相似文献
15.
Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India 总被引:2,自引:1,他引:2
Radon concentrations were measured in soil, air and groundwater in Bhilangana Valley, Garhwal Himalaya, India by using an
LR-115 plastic track detector and radon emanometer. Radon concentrations were found to vary from 1 KBq/m3 to 57 KBq/m3 in soil , 5 Bq/l to 887 Bq/l in water and 95 Bq/m3 to 208 Bq/m3 in air. The recorded values are quite high due to associated uranium mineralization in the area. Radon concentration was
also found to depend on the tectonic structure and geology of the area.
Received: 22 July 1996 · Accepted: 8 January 1997 相似文献
16.
Evaluation of Jordanian faujasite tuff by comparison with other natural and synthetic zeolites 总被引:1,自引:0,他引:1
Khalil M. Ibrahim 《Environmental Geology》2001,40(4-5):440-445
The evaluation of the Jordanian faujasite tuff in wastewater treatment is investigated by comparison with synthetic faujasite
(13X) and clinoptilolite-rich tuff. The material used (JORD-FAUJ) is concentrated by mineral processing techniques. It has
a faujasite content of 57% and phillipsite content of 35%. Thorough characterization of the JORD-FAUJ revealed the high suitability
of the product for use in column operation. It either compares closely or gives better thermal stability, attrition resistance,
acid resistance, cation exchange capacity (CEC) and water absorption capacity, when compared with products already recommended
in column operation. The study has also revealed that the JORD-FAUJ competes efficiently in ammonium removal with the synthetic
faujasite 13X and clinoptilolite-rich tuff and gives similar performance. JORD-FAUJ gave a very high performance in removing
Pb, Cr, Cu, Zn, and Ni from wastewater, equivalent to 83–100% of that of faujasite 13X and much higher than the clinoptilolite-rich
tuff.
Received: 13 April 2000 · Accepted: 1 August 2000 相似文献
17.
As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Se and Zn concentrations were determined and compared in lake and overbank sediments
from 33 catchments without local pollution sources in southern Norway. There were no significant differences in concentrations
of Be, Co, Cr, Cu, Ni, and V in overbank and pre-industrial lake sediments. In areas with shallow overburden, and significant
influence from long-range atmospheric pollution, concentrations of As, Cd, Hg, Pb, Se, and Zn in overbank sediments were probably
modified by vertical percolating water. In such areas, we suggest using lake sediments as a better sampling medium for mapping
pre-industrial concentrations. Pre-industrial lake sediments yield natural concentrations of Hg and Se, which consist of both
geogenic and natural atmospheric deposition. Important covariables like organic carbon content, Fe oxides, and fine mineral
fraction were generally higher in pre-industrial lake sediments as compared to overbank sediments. By adjusting for such differences
overbank sediments could be used as an alternative in mapping background concentrations of trace metals in regions with few
lakes.
Received: 19 February 1999 · Accepted: 17 April 1999 相似文献
18.
The most commonly recognized sources of sand and gravel aggregate are the deposits of coastal, fluvial and glacial sedimentary
processes. It is not commonly recognized that weathered bedrock is also an important source of sand and gravel aggregate.
In the case of weathered sedimentary bedrock the product may be indistinguishable from modern sedimentary materials and deposits
may be misidentified. Batson's quarry is a major sand and gravel aggregate resource for the rapidly developing region of north-eastern
New South Wales. The deposit has previously been assumed to be a young sedimentary deposit, but detailed field examination
and comparison with surrounding rock types indicates that it has formed from weathered Mesozoic sandstone bedrock. The extraction
of weathered bedrock aggregate deposits has distinctive environmental implications because, unlike sedimentary aggregates,
they are not restricted by the geometry of sedimentary environments and do not necessarily interfere with surface drainage
systems. This study shows that the recognition of the geological origin of a resource is essential in order to determine its
potential geographical extent, and thereby maximize its utilization and minimize land use conflict.
Received: 3 January 1996 / Accepted: 1 November 1996 相似文献
19.
20.
Study of the radon concentrations in drinking water from three main cities of Shaanxi Province,China
This paper presents the results of radon concentration measurements in the drinking water from the municipal water supply system and private wells of Xian, Xianyang and Baoji city of Shaanxi province of China. The measurements were carried out on 38 samples. Radon levels in drinking water in Xian, Xianyang and Baoji were found to be 5.78, 13.04 and 15.01 k Bq m–3, respectively. The AM radon concentration of private well water from Xianyang and Baoji is 28.84 k Bq m–3 and 38.85 k Bq m–3, respectively, which is 2.56 times and 3.14 times as high as that of tap water radon, respectively. The radiation risk of radon in water would be due to degassing and not due to drinking water. The domestic use of showers, humidifiers, and cooking, washing up, laundering, etc. may lead to an additional increase of the radon concentration in the indoor air. The observed radon concentration in drinking water from three main cities of Shaanxi Province can contribute to a 4.86 to 32.63% increase in indoor radon concentration and can cause 0.068±0.016 mSv y–1 to 0.177±0.045 mSv y–1 extra annual effective dose to males, 0.060±0.014 mSv y–1 to 0.155±0.039 mSv y–1 to females. The mean annual effective dose equivalents to males and females of Xianyang and Baoji from well water account for 25.94 to 39.75% of environmental radon and radon daughters annual effective dose equivalents. The radon concentrations in the well water from Xianyang and Baoji will bring a definite additional risk to the population. 相似文献