Analysis of benzene transport in a two‐dimensional aquifer model

In this study, the fate and transport of aqueous benzene was investigated in a laboratory‐scale homogeneous aquifer by conducting a two‐dimensional plume test. Benzene solution was introduced as a pulse type along the width of the aquifer model through a recharge zone situated at the upper‐left part of the model and followed by a steady state flow. Solution samples were collected at various locations on the front side of the model to capture two‐dimensional plumes at discrete time intervals. The benzene plumes showed a moderate retardation relative to chloride plumes observed from the previous study conducted for the same aquifer model. The retardation factor was obtained from the ratio of travel distances of benzene peaks to chloride peaks from the injection point, computed using a line integral method. Mass recovery of aqueous benzene revealed that there was a significant reduction of benzene mass, indicating the occurrence of volatilization and/or irreversible sorption during transport. Thus, retardation along with volatilization and/or irreversible sorption may be important processes affecting the fate and transport of aqueous benzene in the aquifer model. Copyright © 2005 John Wiley & Sons, Ltd.     

Multivariate statistical analysis to identify the major factors governing groundwater quality in the coastal area of Kimje,South Korea

The main purpose of this study is to identify the major factors affecting groundwater quality by means of multivariate statistical analysis of the physico‐chemical compositions. Cluster analysis results show that the groundwater in the study area is classified into four groups (A, B, C and D), and factor analysis indicates that groundwater composition, 81·9% of the total variance of 17 variables, is mainly affected by three factors: seawater intrusion, microbial activity and chemical fertilizers. These results might be related to the geographical characteristics of the study area. The main influence on groundwater in groups B, C and D, which are close to the Yellow Sea and contain reclaimed areas, is the seawater intrusion by the present seawater, the trapped seawater, and microbial activity. Group A, however, has been used for agriculture for a long time, and thus groundwater in this group has been largely affected by chemical fertilizers. As groundwater flows from group A to group D according to its path, the governing factor of the groundwater quality gradually changes from chemical fertilizers to microbial activity and seawater intrusion. Copyright © 2004 John Wiley & Sons, Ltd.     

Seasonal hydrochemistry of a high Arctic wetland complex

The seasonal evolution in the hydrochemistry of four types of wetland (pond, ice wedge trough, wet meadow and mesic site) was studied in a 0·5 km² wetland complex in the Canadian High Arctic on the Fosheim Peninsula, Ellesmere Island. In the spring, a large influx of overland runoff from snowmelt quickly flushed away the solutes of the ice stored on the wetland surface over the winter, and homogenized the hydrochemistry across the entire wetland complex. As the surface flow receded, various wetland patches became hydrologically disconnected and their hydrochemical characteristics evolved differently. Although underlain by marine sediments and saline permafrost, solute concentrations in much of the wetland complex remained dilute compared with many Arctic wetlands. Through continued evaporation, melting of ground ice and localized thermokarst activities, the hydrochemistry of different wetland types acquired their distinctive characteristics as the summer progressed. This study demonstrates that large diversity in wetland hydrochemistry occurs even within a limited area, indicating the need to caution against generalizations based on limited spatial and temporal samples. Copyright © 2009 John Wiley & Sons, Ltd.     

Soil moisture monitoring on a steep hillside

In this study, a soil monitoring system for a hillslope with steep relief and shallow soil depth was designed and installed to represent efficiently the spatial and temporal features of soil moisture. The study was conducted on a mountainous hillslope of the Sulmachun catchment (northeastern South Korea). The positions of soil moisture sensors were determined through a sequential procedure including intensive geomorphologic surveying of the study area, surface and subsurface terrain analysis, and inverse surveying. Using 26 sensors, soil moisture data from 11 locations were measured and recorded at hourly intervals over 380 h from 6 to 22 November 2003. Soil moisture response patterns were captured for a few consecutive rainfall events. The monitoring results are discussed in the context of soil moisture variations with terrain attributes. The immediate recharge and fast recession after a peak are the primary features of soil moisture in the upper zone. Stability and significant storage increase are distinct characteristics of soil moisture in the buffer zone and the flow path zone respectively. Spatial distribution of temporal soil moisture variations can be characterized in terms of recession, stability and recharge depending upon the topographic classification of a hillslope for this approach. Copyright © 2007 John Wiley & Sons, Ltd.     

STREAMFLOW CHARACTERISTICS OF THE EASTERN QINGHAI-XIZANG PLATEAU

The eastern Qinghai-Xizang (Tibet) Plateau is the headwater area for many large Asian rivers. Permafrost occurs above 4,200 m a.s.l. and glaciers occupy the summits and high valleys of the east-west trending mountain chains. Annual runoff generally increases with precipitation which is augmented southward by the rise in topography. Rainfall, snow melt, glacier melt and groundwater are the primary sources of stream flow, and the presence of permafrost enhances the flashiness of runoff response to rainfall and snowmelt events. Peak flows are concentrated between June and September. And winter is low flow season. Three types of runoff patterns may be distinguished according to their primary sources of water supply: snowmelt and rainfall, glacier melt and snowmelt, and groundwater. Large rivers generally drain more than one environments and their runoff regime reflects an integration of the various flow patterns on the plateau.     

Application of a newly developed column test device to analyze seawater transport in sandy soils

To verify the applicability of the time-continuous electrical conductivity (EC) measurement in analyzing the contaminant movement in the subsurface, a new column test device employing non-destructive four-electrode sensors was developed. Using the seawater to create a simple one-dimensional steady-flow condition, laboratory transport experiments were conducted and the EC breakthrough curves at different distances were obtained. Comparison between the EC breakthrough curves obtained from the EC sensors and those from the effluent solute chemical analysis showed that the estimated resident concentration from the EC breakthrough curves are useful in understanding solute transport in soils. The pore water velocity and longitudinal dispersion coefficient estimated using the computer code, CXTFIT, were found to be slightly underestimated, especially at sensors located at smaller distances from the outlet boundary. Results showed that the developed column test device employing the four-electrode sensors proposed in this study provides a non-destructive, convenient, and inexpensive means of evaluating the seawater transporting in soils.     

Historical development of the British and Scandinavian earthquake archives

The study of historical earthquakes itself has an interesting history, and Nick Ambraseys figures highly in it. This historiographic tribute relates the pivotal role that he played in the development of the British and Scandinavian Earthquake Archives. Maintaining his academic distance from direct hazard consulting, he nevertheless exerted a significant influence on the scientific conduct of hazard analyses. From the collection of instrumental and macroseismic data to the assignment of magnitudes, the modus operandi which he recommended was followed in pioneering seismic hazard studies in Britain, the North Sea and Norway, during the 1980s. Because of the confidentiality of seismic hazard reports produced for the UK nuclear industry, there is little record in the open seismological literature of the contribution of Nick Ambraseys. As a civil engineer, he had an exceptional interest in the earthquake evidence that could be gleaned from historical documents. An illustrative reference is given to the discovery of fresh evidence from an Aegean earthquake that shows how even the most knowledgeable of earthquake historians can be surprised.     

Radiolarian-bearing conglomerate from the Hayang Group, the Kyongsang Supergroup, southeastern Korea

The non-marine Cretaceous Kyongsang Supergroup, which is divided into the Sindong, the Hayang and the Yuchon groups, is widely distributed in southeastern Korea. Radiolarian-bearing pebbles are collected from the conglomerates of the Kumidong and the Kisadong formations of the Hayang Group. The age of radiolarian fossils range from Late Permian to Middle Jurassic. In Korea, Permian to Middle Jurassic marine chert beds are not exposed. The directions of paleocurrents of the Kumidong and the Kisadong formations are mainly from the northeast to southwest. During Cretaceous time, the Mino-Tamba Belt, within which Permian to Middle Jurassic chert beds are exposed, is suggested to have been located northeast of the Kyongsang Basin. The radiolarian faunas of the Hayang Group are similar to those of the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan (e.g. the Ashio Belt). The provenance of the radiolarian-bearing pebbles collected from the Kumidong and the Kisadong formations is interpreted to be the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan.     

浅谈韩国的溶洞保护与开发—— 以三陟市新基面大耳里地区幻仙洞为例

韩国的溶洞开发虽然起步较晚，但其对溶洞的保护却有许多值得学习和借鉴之处，本文以幻仙洞为例介绍了韩国的溶洞开发现状、管理问题、相关法律法规及保护措施，并提出了作者的建议。