title: High resolution modeling of agricultural nitrogen to identify private wells susceptible to nitrate contamination.
abstract: Given the lack of data on private wells, public health and water quality specialists must explore alternative datasets for understanding associated exposures and health risks. Characterizing agricultural nitrogen inputs would be valuable for identifying areas where well water safety may be compromised. This study incorporated existing methods for estimating nutrient loading at the county level with datasets derived from a state permitting program for confined animal feeding operations and agricultural enterprise budget worksheets to produce a high resolution agricultural nitrogen raster map. This map was combined with data on soil leachability and new well locations. An algorithm was developed to calculate nitrogen loading and leachability within 1,000 meters of each well. Wells with a nonzero nitrogen total linked to soils with high leachability were categorized and displayed on maps communicating well susceptibility across the state of Oregon. Results suggest that 4% of recently drilled wells may be susceptible to nitrate contamination, while areas identified for mitigation are too restrictive to include all susceptible wells. Predicted increases in population density and the steady addition of approximately 3,800 new wells annually may lead to a large number of residents, especially those in rural areas, experiencing long-term exposures to nitrate in drinking water.
authors.affiliation: 2423 Hayes Street NE, Minneapolis, MN 55418, USA E-mail: brendahoppe@gmail.com.
authors.forename: Brendalynn
authors.initials: B
authors.lastname: Hoppe
authors.affiliation: 752 SE Summerfield Pl, Corvallis, OR 97333-2176, USA.
authors.forename: Denis
authors.initials: D
authors.lastname: White
authors.affiliation: Oregon State University, 100 Milam Hall, Corvallis, OR 97331, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Harding
authors.affiliation: USDA-ARS, 109 Crop Science Building, Corvallis, OR 97331-3002, USA.
authors.forename: George
authors.initials: G
authors.lastname: Mueller-Warrant
authors.affiliation: 2020 SW 4th Ave, Suite 300, Portland, OR 97201-4973, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Hope
authors.affiliation: 800 NE Oregon Street, Suite 640, Portland, OR 97232, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Main
mesh_terms: D000383:Agriculture; D004784:Environmental Monitoring / Q000379:methods*; D005308:Fertilizers / Q000032:analysis*; D008372:Manure / Q000032:analysis*; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis*; D009922:Oregon; D062206:Spatial Analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060986:Water Wells / Q000032:analysis
chemical_list: D005308:Fertilizers; D008372:Manure; D014874:Water Pollutants, Chemical; D009584:Nitrogen