Statistical characterization of ground-water quality in the Piedmont of North Carolina, and some ground-water quality differences related to land use
Geological Society of America 1992 Abstracts with Programs
By Douglas A. Harned
Abstract
Analyses of published and unpublished water-quality data collected during the period
1938 to 1986 by the U.S. Geological Survey and the North Carolina Department of
Environment, Health, and Natural Resources were used to characterize ground-water
quality in the Piedmont of North Carolina. Chemical analyses of 2,477 ground-water
samples from 1,238 sites were evaluated. The median depth of sampled wells was 75 feet
(N=1,668), and the median water level was 18 feet below land surface (N=983).
Water-quality analyses for major constituents, nutrients, and some metals were
included in the data set. The median for pH was 6.6; for specific conductance, 120
microsiemens per centimeter (uS/cm); for total hardness, 40 milligrams per liter (mg/L)
as calcium carbonate; for total alkalinity, 43 mg/L; and for bicarbonate, 51 mg/L. The
median concentration for calcium was 13 mg/L; for magnesium, 3.2 mg/L; for sodium,
8.4 mg/L; for sulfate, 5.0 mg/L; and for chloride, 3.5 mg/L. The median concentration
for nitrite plus nitrate was 0.37 mg/L; for total ammonia, 0.05 mg/L; for total phosphorus,
0.05 mg/L; and for total potassium, 1.6 mg/L. The median concentration for aluminum
was 100 micrograms per liter (ug/L); for iron, 100 ug/L; and for manganese, 50 ug/L.
The number of samples for this data set ranged from 527 (calcium) to 2,189 (iron).
In general, ground-water beneath the landfills had the highest median specific
conductance (263 uS/cm) but relatively low nutrient concentrations (nitrite plus nitrate,
0.08 mg/L , and total phosphorus, 0.08 mg/L) compared to other land uses. Ground water
associated with agricultural land uses had the highest median concentrations of nitrite
plus nitrate (1.5 mg/L), followed by commercial (0.92 mg/L), and residential land uses
(0.90 mg/L), all of which were considerably higher than ambient levels (0.16 mg/L).
Citation:
Harned, D.A., 1992, Statistical characterization of ground-water quality in the Piedmont of North Carolina, and some ground-water quality differences related to land use [abs.]: Geological Society of America 1992 Abstracts with Programs, v. 24, no. 2, p. 20.
For more information, contact |
To order printed copies, contact |
North Carolina Water Science Center
U.S. Geological Survey
3916 Sunset Ridge Road
Raleigh, North Carolina 27607
(919) 571-4000
E-mail
|
North Carolina Water Science Center
U.S. Geological Survey
3916 Sunset Ridge Road
Raleigh, North Carolina 27607
(919) 571-4037
E-mail
|
U.S. Geological Survey
Information Services
Box 25286, Federal Center
Denver, CO 80225
1-888-ASK USGS
|
|