『Abstract
A regional-scale groundwater study was conducted over a 2-year
period to assess the extent of nitrate contamination and source
identification for southern Baldwin County, AL. Groundwater wells
were samples and analyzed for nitrate and a host of other geochemical
parameters which revealed that extensive areas within aquifer
zone A2 exhibited nitrate concentrations exceeding regulatory
limits. Spatial iso-concentration maps of nitrate were constructed
using ArcGIS software to determine the extent and severity of
contamination for the aquifers underlying southern Baldwin County
with the primary interest focused on the heavily utilized aquifer
zone A2. Nitrate levels in the central and northeastern portion
of the study area were most extensive with maximum concentrations
of 63 mg/L likely resulting from agricultural inputs. several
other small regions throughout the study area exhibited elevated
levels of nitrate and chloride as high as 112 and 51.1 mg/L, respectively,
and sources likely vary (i.e., residential septic systems, animal
waste to agriculture). With the exception of a few groundwater
samples, there was no obvious correlative relationship between
chloride and nitrate concentration for data collected during the
2-year period. Collectively, a general inverse relationship between
nitrate concentrations and well depth was observed for the aquifer
system under investigation. The study provides an initial current
data set of areas impacted or most vulnerable to nitrate contamination
and initial assessment of likely sources of nitrate in the region.
Keywords: Nitrate; Groundwater contamination; GIS; Southern Baldwin
County』
Introduction
Background
Previous studies
Site description
Location and extent of the study area
Population and land-use/land-cover
Stratigraphy and hydrogeology
Methodology
Data collection
Sample analysis
Geographic information system (GIS)
Results
Regional and local groundwater flow
2006 Groundwater nitrate data
2007 Groundwater nitrate data
Discussion
Temporal changes
Potential sources
Conclusions
Acknowledgements
References