TY - JOUR
T1 - Distribution of bromide and microspheres along macropores in and between drain trenches
AU - Nielsen, Marie Habekost
AU - Styczen, Merete Elisabeth
AU - Ernstsen, Vibeke
AU - Petersen, Jens Carsten Tilbæk
AU - Hansen, Søren
PY - 2011/2
Y1 - 2011/2
N2 - Transport and retention of colloids are important issues when addressing the risk of contamination of the aquatic environment. A field study tracer experiment was performed allowing a quantification of solutes and colloids along macropores in a sandy loam soil with a tile drain located at 1.2 m depth. Using a field sprayer, a 6-m 2 plot was irrigated with 50 mm of water containing a mixture of 1-μm imfluorescent microspheres (1.34 x 10 10 melamine-resin microspheres [MS] L -1), bromide (0.14 g Br L -1), and the dye Brilliant Blue (2.2 g BB L -1) during a 4-h period. Before irrigation, the groundwater table was more than 0.7 m below drain depth. The tracer concentrations were measured in drain water and in soil collected along 15 stained preferential flow paths located in the drain trench and the adjacent till. It was found that the tracer concentration along biopores do not necessarily reflect the concentration of tracers transported through the biopore. Furthermore, it was recognized that at drain depth the proportion of soil samples from the drain trench with concentrations of Br and MS greater than two times the detection limit was significantly higher than in samples from the till. This implies that substances can accumulate along the drain pipe during heavy precipitation events. Finally, water transported through a few biopores well connected to the drain pipe resulted in drainage. Compared with the concentrations in the added tracer solution, the sampled drain water showed undiluted concentrations of BB and Br, whereas MS was reduced 150 times.
AB - Transport and retention of colloids are important issues when addressing the risk of contamination of the aquatic environment. A field study tracer experiment was performed allowing a quantification of solutes and colloids along macropores in a sandy loam soil with a tile drain located at 1.2 m depth. Using a field sprayer, a 6-m 2 plot was irrigated with 50 mm of water containing a mixture of 1-μm imfluorescent microspheres (1.34 x 10 10 melamine-resin microspheres [MS] L -1), bromide (0.14 g Br L -1), and the dye Brilliant Blue (2.2 g BB L -1) during a 4-h period. Before irrigation, the groundwater table was more than 0.7 m below drain depth. The tracer concentrations were measured in drain water and in soil collected along 15 stained preferential flow paths located in the drain trench and the adjacent till. It was found that the tracer concentration along biopores do not necessarily reflect the concentration of tracers transported through the biopore. Furthermore, it was recognized that at drain depth the proportion of soil samples from the drain trench with concentrations of Br and MS greater than two times the detection limit was significantly higher than in samples from the till. This implies that substances can accumulate along the drain pipe during heavy precipitation events. Finally, water transported through a few biopores well connected to the drain pipe resulted in drainage. Compared with the concentrations in the added tracer solution, the sampled drain water showed undiluted concentrations of BB and Br, whereas MS was reduced 150 times.
U2 - 10.2136/vzj2010.0078
DO - 10.2136/vzj2010.0078
M3 - Journal article
SN - 1539-1663
VL - 10
SP - 345
EP - 353
JO - Vadose Zone Journal
JF - Vadose Zone Journal
IS - 1
ER -