How do nutrient concentrations at NAWQA agricultural and urban sites compare to U.S. Environmental Protection Agency (USEPA) recommended nutrient criteria?
Total nitrogen and phosphorus concentrations at NAWQA sites are greater than USEPA recommended ecoregional nutrient criteria at both agricultural and urban sites in some regions of the Nation. For example, the median concentration for sites within a specific nutrient ecoregion ranges from about 2 to over 10 times the respective ecoregional criterion for both total nitrogen and total phosphorus. In addition, a model developed using NAWQA data for total nitrogen in streams predicts widespread occurrence of concentrations above the proposed nutrient criteria for total nitrogen concentrations. The large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, may be needed to meet recommended criteria for streams draining areas with significant agricultural and urban development.
Related Questions
- Are estimated background nutrient concentrations using the USGS SPARROW model and U.S. Environmental Protection Agency (USEPA) recommended criteria for ecoregions similar?
- How does predicted total nitrogen concentrations in streams compare to U.S. Environmental Protection Agency (USEPA) recommended nutrient criteria?
- How did NAWQA determine regional background nutrient concentrations to compare with regional nutrient criteria?
