The Urban Environmental Gradient: Anthropogenic Influences on the Spatial and Temporal Distributions of Lead and Zinc in Sediments
Edward Callender, U.S. Geological Survey,
National Center MS 432, 12201 Sunrise
Valley Drive, Reston, Virginia 20192; Karen C.
Rice, U.S. Geological Survey, P.O. Box B, Charlottesville, Virginia 22903
Urban settings are a focal point for
environmental contamination due to emissions from industrial and municipal
activities and the widespread use of motor vehicles. As part of the National
Water-Quality Assessment Program of the U.S. Geological Survey,
streambed-sediment and dated reservoir-sediment samples were collected from the
Chattahoochee River Basin and analyzed for total lead (Pb) and zinc (Zn)
concentrations. The sampling transect extends from northern Georgia, through
Atlanta, to the Gulf of Mexico and reflects a steep gradient in population
density from nearly 1000 people/km2 in the Atlanta Metropolitan Area to fewer
than 50 people/km2 in rural areas of southern Georgia and northern Florida.
Correlations among population density, traffic density, and total and
anthropogenic Pb and Zn concentrations indicate that population density is
strongly related to traffic density and is a predictor of Pb and Zn
concentrations in the environment derived from anthropogenic activities.
Differences in the distributions of total Pb and Zn concentrations along the
urban-suburban-rural gradient from Atlanta to the Florida Panhandle are related
to temporal and spatial processes. That is, with the removal of leaded gasoline
starting in the late 1970s, peak Pb concentrations have decreased to
the present. Conversely, increased vehicular usage has kept Zn concentrations
elevated in runoff from population centers, which is reflected in the continued
enrichment of Zn in aquatic sediments. Sediments from rural areas also contain
elevated concentrations of Zn, possibly in response to substantial power plant
emissions for the region, as well as vehicular traffic.
Callender, E., and Rice, K.C., 2000, The urban environmental gradient--Anthropogenic influences on the spatial and temporal distributions of lead and zinc in sediments: Environmental Science and Technology, v. 34, no. 2, p. 232-238. [Abstract]
Contact: GS-W-VArmd_webmaster@usgs.gov
U.S. Department of Interior,
U.S. Geological Survey
Privacy Statement
Disclaimer