Should we worry about NO[sub 3]-N contamination in groundwater systems that exhibit low redox potentials

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:7206941

Simpkins, W W; Johnson, B L; Ariffin, A R ^[1]

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1. Iowa State Univ., Ames, IA (United States). Dept. of Geological and Atmospheric Sciences

Since 1988, research on the processes of agricultural chemical transport in Late Wisconsin till in central Iowa has been undertaken at the Ames Till Hydrology site (ATHS), and recently has been expanded to the Walnut Creek Drainage Basin (WCDB) as part of the Iowa Management System Evaluation Area Project. Because of the expertise of the majority of individuals on these projects, the focus has primarily been on shallow, subsurface transport of chemicals in the root zone or at the water table. Presence or absence of agricultural chemicals such as NO[sub 3]-N at or near the water table was used to assess the potential for contamination of underlying aquifers. Since 1990, the authors have investigated the groundwater geochemistry of the Pleistocene glacial sediment and Paleozoic bedrock in central Iowa. Nearly 50 m of Late Wisconsin till and loess, Pre-Illinoian till, and Pennsylvanian shale comprise the major aquitard in the region. Pre-Illinoian gravel, Pennsylvanian sandstone, and Mississippian limestone comprise the major aquifers in the basin. Twelve piezometers at the ATHS provided groundwater samples in the Late Wisconsin till and loess units to depths of 30 m. For the deeper Pleistocene and bedrock aquifer units (> 80 m), well depths, water levels, and aquifer units were identified by well construction logs followed by a house-to-house survey of residents in the WCDB. These data suggest that NO[sub 3]-N in these systems should have been reduced to N[sub 2]O or N[sub 2] gas. Detectable NO[sub 3]-N concentrations are probably due to casing leaks or sampling problems at the wellhead.

• OSTI ID: 7206941
• Report Number(s): CONF-9303210--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220 -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
540250 -- Environment
Terrestrial-- Site Resource & Use Studies-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
AGRICULTURAL WASTES
AQUIFERS
CHEMICAL REACTIONS
CHEMISTRY
DEVELOPED COUNTRIES
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL TRANSPORT
GEOCHEMISTRY
GROUND WATER
HYDROGEN COMPOUNDS
IOWA
MASS TRANSFER
NITRATES
NITROGEN COMPOUNDS
NORTH AMERICA
ORGANIC WASTES
OXYGEN COMPOUNDS
POLLUTION
REDOX REACTIONS
ROCK-FLUID INTERACTIONS
USA
WASTES
WATER
WATER POLLUTION