Ability of Four Emergent Macrophytes to Remediate Permethrin in Mesocosm Experiments

Abstract

Increased focus is being placed on the ability of native vegetation to mitigate potential harmful effects of agricultural runoff, especially pyrethroid insecticides. Replicate 379 L Rubbermaid tubs (1.25 m [l] 9 0.6 m [w] 9 0.8 m [h]) were planted with individual species of cutgrass (Leersia oryzoides), cattails (Typha latifolia), burreed (Sparganium americanum), and powdery alligator-flag (Thalia dealbata), all common wetland macrophytes found in the Mississippi Delta, USA, agricultural region. Permethrin-enriched water (target concentration, 5 lg L -1 ) was pumped in at a 4-h hydraulic retention time at one end of the tub and discharged at the far end. Water samples were collected from discharge at 1-h intervals for 12 h and analyzed for permethrin concentrations. Permethrin removal rates were compared for the four different plant treatments and nonvegetated sediment-water controls. Results indicated that no particular single plant species was more effective at removing permethrin in water relative to unplanted controls. Overall mass reductions (from inflow to outflow) for cis-permethrin ranged from 67% ± 6% in T. latifolia to 71% ± 2% in L. oryzoides. The trans-permethrin overall mass reductions ranged from 76% ± 4% in S. americanum to 82% ± 2% in the unplanted control. Sediment and plant samples collected at the study conclusion indicated that 77%-95% of measured permethrin mass was associated with sediment for mesocosms planted with L. oryzoides, T. latifolia, and T. dealbata. Conversely, mesocosms planted with S. americanum had 83% of measured mass associated with the plant material. Specific plant-pesticide retention studies can lead to improved planning for best management practices and remediation techniques such as constructed wetlands and vegetated agricultural drainage ditches.

Use of vegetated agricultural drainage ditches to decrease pesticide transport from tomato and alfalfa fields in California, USA

“…Plant-specific mitigation of cis-permethrin in aquatic mesocosms ranged from 67% reduction with Typha latifolia L. to 71% reduction with Leersia oryzoides (L.) Sw. [33]. Within this same study, however, there was no significant difference in permethrin mass mitigation between different plant species and the unvegetated control [33]. The short hydraulic retention time (4 h) was likely the main factor for this lack of discrepancy.…”

“…Schmitt et al [32] reported that filter strips comprising trees, shrubs, and grasses at widths of 7.5 m and 15 m reduced permethrin-associated contaminants by 27 to 83%. Plant-specific mitigation of cis-permethrin in aquatic mesocosms ranged from 67% reduction with Typha latifolia L. to 71% reduction with Leersia oryzoides (L.) Sw. [33]. Within this same study, however, there was no significant difference in permethrin mass mitigation between different plant species and the unvegetated control [33].…”

Evaluation of permethrin-impregnated military uniforms for contact toxicity against mosquitoes and persistence in repeated washings

“…As in the case of other insecticides, the presence of permethrin has been reported in the water bodies receiving run-off, in the United States and the United Kingdom. Permethrin when received in an aquatic system is potentially harmful to the fauna and flora (Moore et al 2009). Hence, the washing of the impregnated uniforms in river water should be discouraged, and the wash water needs to be properly disposed so as to prevent contamination of the environment.…”

Experiments in water-macrophyte systems to uncover the dynamics of pesticide mitigation processes in vegetated surface waters/streams

“…processes in VTS. Beyond that, the ability of aquatic macrophytes to eliminate pesticides from the aqueous phase has been investigated at the laboratory (Crum et al 1999;Olette et al 2008), microcosm (Bouldin et al 2005), and mesocosm scale (Moore et al 2009). Furthermore, Passeport et al (2011) determined high coefficients for pesticide adsorption to wetland plants and forest litter followed by compound-related desorption.…”