Document Detail

Fluorescence imaging applied to tracer distributions in variably saturated fractured clayey till.
MedLine Citation:
PMID:  18268308     Owner:  NLM     Status:  MEDLINE    
The study of mechanisms controlling preferential flow and transport in variably saturated fractured clayey till is often hindered by insufficient spatial resolution or unknown measuring volume. With the objective to study these mechanisms while circumventing the obstacles, tracer experiments with two fluorescent tracers Acid Yellow 7 (AY7) and Sulforhodamine B (SB) were performed at three different rain events for a fall and a summer season. Irrigated areas were excavated down to depths of 2.8 m and the movement of both tracers in the exposed profiles was delineated simultaneously by high spatial resolution apparent concentration maps (pixel approximately 1 mm(2)) obtained with an imaging device. The device consists of a light source and a CCD camera, both equipped with tracer-specific-filters for fluorescent light. The fluorescence images were corrected for nonuniform lighting, changing surface roughness, and varying optical properties of the soil profile. The resulting two-dimensional apparent concentration distribution profiles of the tracers showed that: (i) relative low water content in the upper 10 cm of the irrigated till in summer had a pronounced retardation effect on the AY7-migration and no effect on the SB-migration; (ii) the dead-end biopores were not activated in the fall season; (iii) only 3D fracture-plans connected to hydraulically active 1D-biopores contributed to the leaching; (iv) the tracer migration primary followed macropores during both seasons, though AY7 also followed a topsoil piston transport in summer; (v) the highest tracer pixel apparent concentrations were often found in macropores and most pronounced in the summer season; and (vi) 3D-dilution in fractures seems to play a dominating role in AY7-migration in the fall season.
Annette E Rosenbom; Vibeke Ernstsen; Hannes Flühler; Karsten H Jensen; Jens Christian Refsgaard; Hannes Wydler
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-02-11
Journal Detail:
Title:  Journal of environmental quality     Volume:  37     ISSN:  0047-2425     ISO Abbreviation:  J. Environ. Qual.     Publication Date:    2008 Mar-Apr
Date Detail:
Created Date:  2008-02-12     Completed Date:  2008-06-24     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0330666     Medline TA:  J Environ Qual     Country:  United States    
Other Details:
Languages:  eng     Pagination:  448-58     Citation Subset:  IM    
Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, Copenhagen K, Denmark.
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MeSH Terms
Aluminum Silicates
Fluorescent Dyes / analysis*
Rhodamines / analysis*
Water Movements*
Reg. No./Substance:
0/Aluminum Silicates; 0/Fluorescent Dyes; 0/Rhodamines; 1302-87-0/clay; 2609-88-3/lissamine rhodamine B

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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