caa a22 4500 445814667 CHVBK 20180317145222.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s10040-011-0748-8 doi (NATIONALLICENCE)springer-10.1007/s10040-011-0748-8 The fate and transport of nitrate in shallow groundwater in northwestern Mississippi, USA [Elektronische Daten] [Heather Welch, Christopher Green, Richard Coupe] Devenir et transport des nitrates en aquifère superficiel au Nord-Ouest du Mississippi, Etats-Unis Agricultural contamination of groundwater in northwestern Mississippi, USA, has not been studied extensively, and subsurface fluxes of agricultural chemicals have been presumed minimal. To determine the factors controlling transport of nitrate-N into the Mississippi River Valley alluvial aquifer, a study was conducted from 2006 to 2008 to estimate fluxes of water and solutes for a site in the Bogue Phalia basin (1,250 km2). Water-quality data were collected from a shallow water-table well, a vertical profile of temporary sampling points, and a nearby irrigation well. Nitrate was detected within 4.4 m of the water table but was absent in deeper waters with evidence of reducing conditions and denitrification. Recharge estimates from 6.2 to 10.9 cm/year were quantified using water-table fluctuations, a Cl- tracer method, and atmospheric age-tracers. A mathematical advection-reaction model predicted similar recharge to the aquifer, and also predicted that 15% of applied nitrogen is leached into the saturated zone. With current denitrification and application rates, the nitrate-N front is expected to remain in shallow groundwater, less than 6-9 m deep. Increasing application rates resulting from intensifying agricultural demands may advance the nitrate-N front to 16-23 m, within the zone of groundwater pumping. Springer-Verlag (outside the USA), 2011 Groundwater age nationallicence Nitrate nationallicence Recharge nationallicence Geochemical modeling nationallicence USA nationallicence Welch Heather US Geological Survey, 308 Airport Road, 39208, Jackson, MS, USA aut Green Christopher US Geological Survey, 345 Middlefield Road, 94025, Menlo Park, CA, USA aut Coupe Richard US Geological Survey, 308 Airport Road, 39208, Jackson, MS, USA aut Hydrogeology Journal Springer-Verlag 19/6(2011-09-01), 1239-1252 1431-2174 19:6<1239 2011 19 10040 https://doi.org/10.1007/s10040-011-0748-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10040-011-0748-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Welch Heather US Geological Survey, 308 Airport Road, 39208, Jackson, MS, USA aut NATIONALLICENCE 700 1- Green Christopher US Geological Survey, 345 Middlefield Road, 94025, Menlo Park, CA, USA aut NATIONALLICENCE 700 1- Coupe Richard US Geological Survey, 308 Airport Road, 39208, Jackson, MS, USA aut NATIONALLICENCE 773 0- Hydrogeology Journal Springer-Verlag 19/6(2011-09-01), 1239-1252 1431-2174 19:6<1239 2011 19 10040 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer