Constructed wetlands as a component of the agricultural landscape: Mitigation of herbicides in simulated runoff from upland drainage areas

• Published in: Chemosphere (Oxford) Vol. 83; no. 11; pp. 1532 - 1538
• Main Authors: Locke, M.A., Weaver, M.A., Zablotowicz, R.M., Steinriede, R.W., Bryson, C.T., Cullum, R.F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.06.2011; Elsevier
• Subjects: agricultural land; agricultural runoff; Agriculture; Applied sciences; Atrazine; Atrazine - analysis; chemical concentration; constructed wetlands; Construction; drainage; environmental fate; Environmental Monitoring; Environmental Restoration and Remediation - methods; Exact sciences and technology; Fluometuron; Fresh Water - chemistry; Herbicides; Herbicides - analysis; highlands; Methylurea Compounds - analysis; Models, Chemical; Pollutants; Pollution; pollution control; Runoff; sediments; Simulation; sorption; Water Pollutants, Chemical - analysis; Water Pollution, Chemical - prevention & control; Water Pollution, Chemical - statistics & numerical data; Water quality; watersheds; Wetland; wetland plants; wetland soils; Wetlands; Mississippi Delta region; Mississippi; United States; North America; America; ASW, USA, Louisiana, Mississippi Delta; Fluometuron; Wetland; Water quality; Atrazine; Agricultural chemical product; Upland area; Pollution control; Biological purification; Transport process; Chemical pollution; Watershed; Agriculture; Pollution abatement; Organic compounds; Pesticides; Endocrine disruptor; Runoff water; Sediments; Tailings; Herbicide; Sorption; Industrial waste; Delta; Artificial medium; Surface water; Lakes; Waste water purification; Mining waste
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2011.01.034

► We evaluate herbicide moving through a constructed wetland during a simulated runoff event. ► Atrazine and fluometuron in water decrease as water flows from cell to cell. ► Constructed wetlands improve water quality by pollutant sequestration or processing. Constructed wetlands are a recommended practice for buffering pollutant source areas and receiving waters. A wetland consisting of a sediment trap and two treatment cells was constructed in a Mississippi Delta lake watershed. A 3-h simulated runoff event was initiated (2003) to evaluate fate and transport of atrazine and fluometuron through the wetland. Water samples were collected during a runoff simulation and then afterward at selected intervals for 21 d, and analyzed for the herbicides. Breakthrough patterns for herbicide concentrations in water samples during the first 20 h after simulated runoff showed peak concentrations in the first 6 h, with gradual tailing as the herbicide pulse was diluted in the second, excavated (deeper) cell. Atrazine and fluometuron concentrations in the first (shallower, non-excavated) cell averaged 12- and 20-fold greater, respectively, than those in the second cell following simulated runoff, indicating entrapment in the first cell. Atrazine and fluometuron concentrations in the shallower cell decreased 32% and 22%, respectively, 9 d following simulated runoff, indicating either degradation or sorption to soil or wetland flora. In the excavated cell, concentrations were even lower, and atrazine declined more rapidly than fluometuron. Results indicate constructed wetlands can improve downstream water quality though sequestration or processing of pollutants.