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Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows.

Allaire SE, Sylvain C, Lange SF, Thériault G, Lafrance P - PLoS ONE (2015)

Bottom Line: However, such strips do not intercept all contaminants, particularly soluble ones.Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used.The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

View Article: PubMed Central - PubMed

Affiliation: Département des sols et de génie agroalimentaire, Université Laval, Québec City, Quebec, Canada.

ABSTRACT
Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

No MeSH data available.


Maximal Blue and rhodamine concentrations in the lysimeter plates during both years (no samples were taken from November to beginning of May).
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pone.0131840.g005: Maximal Blue and rhodamine concentrations in the lysimeter plates during both years (no samples were taken from November to beginning of May).

Mentions: The lysimeters rarely worked, except during intense or long precipitation events, resulting in scarce samples. These samples showed average Blue and rhodamine concentrations in the same order of magnitude as those in the creek during rain events (Table 4). However, the maximum concentrations of Blue (50.0 mg L-1) and rhodamine (4.05 x 10−3 mg L-1) were higher than those in the creek in 2011 (0.15 mg L-1 for the Blue and 0.37 x 10−3 mg L-1 for the rhodamine) and lower in 2012 (0.44 mg L-1 for the Blue and 2.60 x 10−3 mg L-1 for the rhodamine). There was always at least one of the tracers in the water in at least one lysimeter. Rhodamine was more frequently observed in lysimeters (in several lysimeters at the same time) than Blue, which was detected almost exclusively in the deepest lysimeters. When Blue was detected, its concentration was at most ten times higher than that of the rhodamine (Fig 5).


Potential Efficiency of Riparian Vegetated Buffer Strips in Intercepting Soluble Compounds in the Presence of Subsurface Preferential Flows.

Allaire SE, Sylvain C, Lange SF, Thériault G, Lafrance P - PLoS ONE (2015)

Maximal Blue and rhodamine concentrations in the lysimeter plates during both years (no samples were taken from November to beginning of May).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492607&req=5

pone.0131840.g005: Maximal Blue and rhodamine concentrations in the lysimeter plates during both years (no samples were taken from November to beginning of May).
Mentions: The lysimeters rarely worked, except during intense or long precipitation events, resulting in scarce samples. These samples showed average Blue and rhodamine concentrations in the same order of magnitude as those in the creek during rain events (Table 4). However, the maximum concentrations of Blue (50.0 mg L-1) and rhodamine (4.05 x 10−3 mg L-1) were higher than those in the creek in 2011 (0.15 mg L-1 for the Blue and 0.37 x 10−3 mg L-1 for the rhodamine) and lower in 2012 (0.44 mg L-1 for the Blue and 2.60 x 10−3 mg L-1 for the rhodamine). There was always at least one of the tracers in the water in at least one lysimeter. Rhodamine was more frequently observed in lysimeters (in several lysimeters at the same time) than Blue, which was detected almost exclusively in the deepest lysimeters. When Blue was detected, its concentration was at most ten times higher than that of the rhodamine (Fig 5).

Bottom Line: However, such strips do not intercept all contaminants, particularly soluble ones.Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used.The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

View Article: PubMed Central - PubMed

Affiliation: Département des sols et de génie agroalimentaire, Université Laval, Québec City, Quebec, Canada.

ABSTRACT
Buffer strips have been widely recognized as to promote infiltration, deposition and sorption of contaminants for protecting surface water against agricultural contamination. However, such strips do not intercept all contaminants, particularly soluble ones. Although preferential flow (PF) has been suggested as one factor among several decreasing the efficiency of buffer strips, the mechanisms involved are not well understood. This project examines buffer strip efficiency at intercepting solutes when subsurface PF occurs. Two soluble sorbed tracers, FD&C Blue #1 and rhodamine WT, were applied on an agricultural sandy loam soil to evaluate the ability of a naturally vegetated buffer strip to intercept soluble contaminants. Rhodamine was applied about 15 m from the creek, while the Blue was applied 15 m to 165 m from the creek. Tracer concentration was measured over a two-year period in both the creek and the buffer strip through soil and water samples. Although the tracers traveled via different pathways, they both quickly moved toward the creek, passing beneath the buffer strip through the soil matrix. Our results demonstrate that the risk of water contamination by soluble contaminants is high in such systems, even when a well-vegetated buffer strip is used. The design of buffer strips should be modified to account for underground bypass, either by using plants that have deep, fine roots that do not favour PF or by adding a filter extending deep underground that can be regularly changed.

No MeSH data available.