title: Mitigation of two pyrethroid insecticides in a Mississippi Delta constructed wetland.
abstract: Constructed wetlands are a suggested best management practice to help mitigate agricultural runoff before entering receiving aquatic ecosystems. A constructed wetland system (180 m x 30 m), comprising a sediment retention basin and two treatment cells, was used to determine the fate and transport of simulated runoff containing the pyrethroid insecticides lambda-cyhalothrin and cyfluthrin, as well as suspended sediment. Wetland water, sediment, and plant samples were collected spatially and temporally over 55 d. Results showed 49 and 76% of the study's measured lambda-cyhalothrin and cyfluthrin masses were associated with vegetation, respectively. Based on conservative effects concentrations for invertebrates and regression analyses of maximum observed wetland aqueous concentrations, a wetland length of 215 m x 30 m width would be required to adequately mitigate 1% pesticide runoff from a 14 ha contributing area. Results of this experiment can be used to model future design specifications for constructed wetland mitigation of pyrethroid insecticides.
authors.affiliation: USDA Agricultural Research Service National Sedimentation Laboratory, Water Quality and Ecology Research Unit, PO Box 1157, 598 McElroy Drive, Oxford, MS 38655, USA. matt.moore@ars.usda.gov
authors.forename: M T
authors.initials: MT
authors.lastname: Moore
authors.forename: C M
authors.initials: CM
authors.lastname: Cooper
authors.forename: S
authors.initials: S
authors.lastname: Smith
authors.forename: R F
authors.initials: RF
authors.lastname: Cullum
authors.forename: S S
authors.initials: SS
authors.lastname: Knight
authors.forename: M A
authors.initials: MA
authors.lastname: Locke
authors.forename: E R
authors.initials: ER
authors.lastname: Bennett
mesh_terms: D000383:Agriculture; D007306:Insecticides / Q000032:analysis; D008922:Mississippi; D009570:Nitriles / Q000032:analysis; D011722:Pyrethrins / Q000032:analysis; D011891:Rain; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods*; D053833:Wetlands
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D014874:Water Pollutants, Chemical; C052570:cyfluthrin; C037304:cyhalothrin