Submitted to: Society of Environmental Toxicology and Chemistry (SETAC)
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2011
Publication Date: N/A
Interpretive Summary: Abstract Only - interpretative summary not required.
Technical Abstract: Agricultural runoff containing nitrogen and phosphorus is a major contributor to eutrophication in aquatic systems. Vegetated drainage ditches lining agricultural fields have been investigated for their potential to mitigate runoff, acting similarly to a wetland as they filter contaminants. The efficiency of three aquatic macrophytes, cutgrass (Leersia oryzoides), cattails (Typha latifolia), and bur-reed (Sparganium americanum), to mitigate ammonia, nitrate, and phosphate from water was investigated. Replicate mesocosms of each plant species were exposed to water enriched with ammonia and nitrate for 6 h and flushed with clean water for an additional 6 h to simulate storm events. After termination of the simulated runoff, all vegetated treatments lowered total Kjeldahl nitrogen loads exiting mesocosms by greater than 50%, significantly more than unvegetated controls. Leersia and Typha were more efficient at lowering dissolved nitrogen, lowering ammonia 42 and 59% and nitrate by 67 and 64%, respectively. Leersia and Typha decreased the loads of dissolved phosphate exiting mesocosms by 50% while Sparganium only decreased dissolved phosphate by 15%. All treatments decreased ammonia and nitrate concentrations within mesocosms by more than 86% after one week, though Typha and Leersia acted more rapidly. In determining the agrochemical mitigation efficiency of different plant species, vegetation in drainage ditches can be better maintained for optimal remediation of agricultural runoff.