Effectiveness of emergent and submergent aquatic plants in mitigating a nitrogen-permethrin mixture

Authors: Lizotte, Richard; Moore, Matthew

Submitted to: Chemistry and Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2017
Publication Date: 5/15/2017
Citation: Lizotte Jr, R.E., Moore, M.T. 2017. Effectiveness of emergent and submergent aquatic plants in mitigating a nitrogen-permethrin mixture. Chemistry and Ecology. 33(5):420-433. https://doi.org/10.1080/02757540.2017.1310849.
DOI: https://doi.org/10.1080/02757540.2017.1310849

Interpretive Summary: Wetland vegetation can be used to clean agricultural runoff containing fertilizer and pesticides and maintain ecological and economic value of water bodies. A series of artificial wetlands planted with two aquatic plant species, common cattail and parrot feather, were dosed with fertilizer and permethrin insecticide to measure how well the two plant species alone or in combination could remove the nitrogen and insecticide mixture when water was either flowing or stagnant. During both scenarios, water was collected from each wetland and analyzed. During the flow period, the combination of two parrot feather wetlands in tandem removed fertilizer more efficiently than the combination of cattail-parrot feather wetlands. When water was stagnant, the cattail only wetland most efficiently removed fertilizer. All wetlands were equally efficient at removing insecticide. The study showed that different wetland plants alone and in combinations have different removal efficiencies for fertilizer while having the same for insecticide in water. Our results are of interest to regulatory and other agencies and the pesticide industry by providing additional information to improve and sustain river, stream and lake water quality and overall environmental quality using a variety of wetland plants as an effective conservation practice.

Technical Abstract: The current study assessed the effectiveness of varying combinations of two common aquatic vascular macrophytes, parrot feather (Myriophyllum aquaticum) and cattail (Typha latifolia) for mitigating contamination from a mixture of nitrogen (ammonium nitrate) and permethrin. Hydraulically connected wetland microcosms (~50 L) in series were used to test both species singly (upstream Myriophyllum only, M; Typha only, T) and in combination (upstream to downstream Myriophyllum into Myriophyllum, MM; Typha into Myriophyllum, TM). During flow, M into MM more efficiently mitigated nitrogen than T into TM. Post-flow, nitrogen removal efficiency was greater for T versus M and MM versus TM. Mean aqueous dissipation half-lives (t1/2) of NH4-N and NO3-N were more rapid in T than M treatments. Ammonium and nitrate t1/2 was highly correlated with plant biomass. Permethrin mitigation efficiencies and t1/2 were not significantly affected by plant type. Trans-permethrin t1/2 was moderately correlated with plant biomass, but not cis-permethrin t1/2. Results of this study indicate differences in aquatic macrophyte species and flow path influence nitrogen removal but not permethrin. However, plant type appears less important than overall plant biomass in ascertaining aquatic macrophyte effectiveness in mitigating a nitrogen-permethrin mixture.