Using aquatic vegetation to remediate nitrate, ammonium, and soluble reactive phosphorus in simulated runoff

Authors: Moore, Matthew; Locke, Martin; KROGER, R - Covington Civil And Environmental

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2016
Publication Date: 7/1/2016
Citation: Moore, M.T., Locke, M.A., Kroger, R. 2016. Using aquatic vegetation to remediate nitrate, ammonium, and soluble reactive phosphorus in simulated runoff. Chemosphere. 2016; 160:149-154. https://doi.org/10.1016/j.chemosphere.2016.06.071.
DOI: https://doi.org/10.1016/j.chemosphere.2016.06.071

Interpretive Summary: Agriculture has come under increased scrutiny over the last two decades for nutrient contributions to water quality. Conservation efforts are underway to utilize vegetation in natural drainage ways to help reduce the nutrient loads leaving agricultural fields. Summer experiments were conducted for two years, and six different plant species were examined for their ability to decrease nitrogen and phosphorus in runoff water. Cattails, a common plant found in drainage ways significantly reduced phosphorus in runoff water. Great variability in nutrient removals were noted among the different plants, which highlights the importance of having a mixture of aquatic plants available to clean runoff water.

Technical Abstract: Within the agriculturally-intensive Mississippi River Basin of the United States, significant conservation efforts have focused on management practices that reduce nutrient runoff into receiving aquatic ecosystems. Only a small fraction of those efforts have focused on phytoremediation techniques. Three replicate mesocosms (1.2 m x 0.15 m x 0.65 m) were planted with monocultures of six different aquatic macrophytes. Three additional unvegetated mesocosms served as controls for a total number of 21 mesocosms. Over two years, mesocosms were amended once each summer with sodium nitrate, ammonium sulfate, and potassium phosphate dibasic to represent nitrogen and phosphorus in agricultural runoff. System retention was calculated using a simple aqueous mass balance approach. Ammonium retention in both years differed greatly, as Panicum hemitomon and Echinodorus cordifolius were significantly greater than controls in the first year, while only Myriophyllum aquaticum and Typha latifolia were significantly greater than controls in the second year. Greater soluble reactive phosphorus retention was observed in T. latifolia compared to controls in both years. Several other significant differences were observed in either the first or second year, but not both years. In the first year’s exposure, P. hemitomon was significantly more efficient than the control, Saururus cernuus, and T. latifolia for overall percent nitrate decrease. Results of this novel study highlight inherent variability within and among species for nutrient specific uptake and the temporal variations of species for nutrient retention. By examining this natural variability, scientists may design phytoremediation systems with greater impact on improving agricultural runoff water quality.