Sampling and measurement of radon-222 in water

Freyer, K.; Treutler, Hanns-Christian; Dehnert, Jörg; Nestler, W.

doi:10.1016/s0265-931x(96)00102-6

Cited by 51 publications

(21 citation statements)

References 2 publications

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“…The water is pumped from an interval ranging from 167 to 187 m below ground surface. Sampling and measurement of radon in groundwater must be carried out with minimal loss of radon (Freyer et al 1997). Every sampling starts with flushing the stagnant water in the monitoring well and in the screen zone.…”

Section: Site Description and Sample Collectionmentioning

confidence: 99%

Correlating recurrent radon precursors with local earthquake magnitude and crust strain near the Chihshang fault of eastern Taiwan

Kuo

Liu

et al. 2011

Nat Hazards

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The active Chihshang fault in the southern segment of longitudinal valley of eastern Taiwan is part of the suture boundary between the Eurasia plate and the Philippine Sea plate. Radon anomalies in groundwater were recorded prior to three major earthquakes-(1) 2003 M w = 6.8 Chengkung, (2) 2006 M w = 6.1 Taitung, and (3) 2008 M w = 5.4 Antung. The epicenters were located 24, 52, and 13 km, respectively, from the radon-monitoring well (D1) in the Antung hot spring about 3 km southeast of the Chihshang fault. Prior to the three major earthquakes, radon decreased from background levels of 787 ± 42, 762 ± 57, and 700 ± 57 pCi/L to minima of 326 ± 9, 371 ± 9, and 480 ± 43 pCi/L, respectively. Based on the radon volatilization model and the rock dilatancy model, this paper correlates the observed radon minima with local earthquake magnitude and crust strain. The correlation is a useful means of forecasting local disastrous earthquakes in the southern segment of longitudinal valley of eastern Taiwan.

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Section: Site Description and Sample Collectionmentioning

confidence: 99%

Correlating recurrent radon precursors with local earthquake magnitude and crust strain near the Chihshang fault of eastern Taiwan

Kuo

Liu

et al. 2011

Nat Hazards

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“…The first application of this method of determining horizontal groundwater flow velocities was undertaken by Hoehn and van Gunten (1989), with further developments by Freyer et al (1997) and Dehnert et al (1998). The method assumes homogeneity of 222 Rn emanation in the soil, and determines the background equilibrium concentration A e needed for the calculation at a remote observation borehole.…”

Section: Direct Measurement Of Infiltration Rates Using 222 Rnmentioning

confidence: 99%

New Approaches for Estimating Streambed Infiltration Rates

Macheleidt

Grischek

Nestler

2006

Nato Science Series: IV: Earth and Environmental Sciences

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Abstract:Direct quantification of infiltration rates and darcy velocities at bank filtration sites by field measurements has been done only at sites that are well equipped with monitoring wells and is mostly based on the observation of changes in chloride or oxygen-18 concentrations in surface water and infiltrate. The main determinants of the interaction between surface water and groundwater are the distribution of areas with different infiltration rates, the thickness of sediment layers and the hydraulic head gradient. These conditions determine the volume and velocity of infiltrating water which, together with the direction of water flow, are required to model the interaction processes. Usually, due to difficulties with measurement, only the direction of water flow is determined and boundary conditions are estimated from simplified assumptions.Field techniques have now been developed to help characterise surface water/groundwater interaction. Results from field experiments using a percussion probe and a large-scale laboratory column experiment set up to simulate infiltration processes are presented.Owing to its differing concentrations in groundwater and river water, the naturally occurring isotope Radon-222 ( 222 Rn) can be used as a natural tracer to determine the residence time of infiltrated water. The principle is based on the determination of 222 Rn activity at defined points along the flow path. Investigations performed in a large-scale laboratory column experiment showed that different effects considerably influence infiltration measurements. Local sedimentary stratification has a substantial influence on the equilibrium concentration of 222 Rn. Furthermore, investigations in zones with gas formation (e.g. in biologically active zones such as river beds) must consider diffusion of 222 Rn into the gas phase and the reduction of permeability because of gas within the pore space. The volume of gas in the saturated, upper zone of the aquifer has an important influence on the results of 222 Rn measurements. 73Stephen A. Hubbs (ed.), Riverbank Filtration Hydrology, 73-91.

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“…In the past 25 years, radon levels were measured in groundwater and spas in various countries such as Taiwan (Lin and Chen 1983;Sabol et al 1995), Finland (Asikainen and Kahlos 1980), Norway (Banks et al 1998a;Banks et al 1998b), Germany (Freyer et al 1997), Spain (Soto et al 1995a;Soto et al 1995b), Kenyan (Otwoma and Mustapha 1998), Saudi Arabia (Alabdula'aly 1996; Alabdula'aly 1999), and the United States (Brutsaert et al 1981;King et al 1982;Sasser and Watson 1978;Loomis 1987;Cech et al 1988;Longtin 1988;Dixon and Lee 1988;Hess et al 1985). Figure 8 summarizes worldwide radon levels in groundwater and spas reported in the literature.…”

Section: Worldwide Comparison Of Radon Levels In Groundwatermentioning

confidence: 99%

Radon distribution in groundwater of Taiwan

et al. 2004

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Radon levels were surveyed in 517 monitoring wells constructed in five major groundwater areas of Taiwan. The radon concentration in groundwater samples varied in a wide range from below the detection limit of 18 pCi/L up to 1,100 pCi/L. A worldwide comparison of reported groundwater radon levels was conducted. Overall radon levels in Taiwan groundwater are relatively low compared to other countries because the geology of Taiwan is mainly comprised of sedimentary rocks. Among the 517 wells monitored, only five wells were found with radon concentrations higher than 500 pCi/L. These five wells are all located near the Chaochou Fault in the Pingtung Plain. This study suggests that well sites near the Chaochou Fault could be good locations to monitor radon anomalies for earthquake prediction and should be avoided for developing domestic water supply. In the recharge area near the Chaochou Fault, the radon concentration in groundwater from shallow wells was approximately 1/2 to 1/4 of that from deep wells in the same cluster.Resumen Se investigaron los niveles de radón en 517 pozos de monitoreo, construidos en las cinco mayores µreas de agua subterrµnea de Taiwan. La concentración de radón en las muestras de agua subterrµnea varía en un rango amplio, desde inferior al límite de detección que es 18 pCi/L hasta 1,100 pCi/L. Se realizó una comparación a escala mundial de los niveles de radón reportados en agua subterrµnea. En general los niveles de radón presente en el agua subterrµnea de Taiwan, son relativamente bajos comparados con otros países, puesto que la geología de Taiwan estµ compuesta de rocas sedimentarias. Entre los 517 pozos monitoreados, solamente en cinco se encontraron concentraciones de radón mayores a 500 pCi/L. Estos cinco pozos estµn todos localizados cerca de la falla ChaoChou en la Planicie de PingTung. El presente estudio sugiere que los pozos cercanos a la falla Chaochou, podrían ser buenos sitios para monitorear anomalías de radón para la predicción de terremotos y deberían evitarse para los desarrollos de abastecimiento de agua potable. En la zona de recarga cerca de la falla Chaochou, la concentración de radón en agua subterrµnea obtenida en pozos someros, fue aproximadamente de a de aquella en pozos profundos ubicados en el mismo sector.

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Sampling and measurement of radon-222 in water

Cited by 51 publications

References 2 publications

Correlating recurrent radon precursors with local earthquake magnitude and crust strain near the Chihshang fault of eastern Taiwan

Correlating recurrent radon precursors with local earthquake magnitude and crust strain near the Chihshang fault of eastern Taiwan

New Approaches for Estimating Streambed Infiltration Rates

Radon distribution in groundwater of Taiwan

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