U.S. Geological Survey |
New Jersey District |
U.S. Geological Survey |
New Jersey District | The NAWQA Program is organized into 59 study units distributed throughout the United States on the basis of regional aquifers and major river basins. Work in the Long Island-New Jersey (LINJ) study unit (6,000 square miles), one of the most heavily urbanized and populated of the study units, began in 1994.
Along with organic contaminants, trace elements have been identified by water-quality experts as a high-priority issue in New Jersey. Streambed sediments can be a source or sink of trace elements depending on the physicochemical conditions in the water column. Concentrations of trace elements in bed sediments are of particular interest because they may reflect the concentrations in aquatic organisms.
In this study, results of analyses of streambed sediments collected at 295 sites throughout New Jersey during 1976-93 were analyzed. Samples were collected as part of the USGS/ New Jersey Department of Environmental Protection (NJDEP) cooperative water-quality monitoring network. Primary objectives were to (1) document the distribution of trace elements in streambed sediments throughout the State and (2) determine whether the presence of elevated concentrations of trace elements is related to basin characteristics, particularly land use. This fact sheet presents the results of these analyses.
Trace elements in streambed sediments are derived from a variety of sources, including weathering of rocks and soils and both indirect and direct anthropogenic sources. Major indirect sources include atmospheric deposition; industrial emissions from activities such as plating, smelting, and refining; wastewater discharges; landfills; stormwater runoff; and automobile exhaust. Examples of direct sources are fertilizers, inorganic pesticides, and industrial solvents (Fields and others, 1993). Distinguishing among these sources is extremely difficult because of the widespread, undocumented use and industrial release of metals.
--------------------------------------------------------------------------------
Table 1. Land use and population density in major physiographic provinces of
New Jersey [Anderson level I and level II land-use data from Fegeas and others
(1983); population data from U.S. Bureau of the Census (1991). Land-use values
are in percent. CP, Coastal Plain; PD, Piedmont; PDG, Piedmont (glaciated); NE,
New England; NEG, New England (glaciated); VR, Valley and Ridge, <, less than].
--------------------------------------------------------------------------------
CP PD PDG NE NEG VR
--------------------------------------------------------------------------------
Land use (in percent of physiographic province)
Urban 6 8 27 3 3 1
Residential 13 17 51 11 13 3
Agricultural 24 48 1 33 8 45
Forest 35 23 11 51 69 46
Water 4 2 4 <1 5 2
Wetland 16 2 4 <1 <1 2
Barren 2 <1 2 <1 1 1
Average population density (people per acre) 1.0 1.4 7.1 0.8 0.8 0.2
--------------------------------------------------------------------------------
Because land use and population-density vary within the provinces, particularly the Coastal Plain, analyses by major drainage area also were conducted to examine differences in trace-element concentrations with land use. Twelve major drainage basins were selected to represent various stages of development. In order to ensure an adequate number of samples per basin for comparison, the 12 basins were combined into 7 drainage areas (figure 2). The combined basins are adjacent to one another and had similar land use and population density in the 1970's. Land-use and population-density information for the 7 drainage areas is summarized in table 2.
-------------------------------------------------------------------------------
Table 2. Land use and population density in selected drainage areas of New Jersey
[Anderson level I and level II land-use data from Fegeas and others (1983);
population data from U.S. Bureau of the Census (1991). Land-use values are in
percent. RAWA, Rahway River; BTCR, Big Timber Creek and Cooper River; PSSC,
Passaic River; RRTN, Raritan River; GEMU, Great Egg Harbor and Mullica rivers;
SRRC, Salem River and Raccoon Creek; PPP, Pequest River, Paulins Kill, and
Pohatcong Creek; <, less than].
-------------------------------------------------------------------------------
RAWA BTCR PSSC RRTN GEMU SRRC PPP
-------------------------------------------------------------------------------
Land use (in percent of drainage area)
Urban 28 17 13 9 2 3 2
Residential 57 45 35 17 6 6 4
Agricultural 1 16 3 40 12 64 43
Forest 10 17 41 30 54 11 47
Water <1 2 3 1 2 5 2
Wetland 3 1 4 2 23 11 2
Barren <1 2 1 1 1 <1 <1
Average population (people per acre) 7.2 5.7 3.5 1.7 0.4 0.6 0.4
-------------------------------------------------------------------------------
The Pequest River/Paulins Kill/Pohatcong Creek drainage area lies entirely within the Valley and Ridge Physiographic Province and the Salem River/Raccoon Creek, Big Timber Creek/Cooper River, and Great Egg Harbor/Mullica River drainage areas are entirely within the Coastal Plain. The Rahway River drainage area lies entirely within the Piedmont (glaciated) Province. The Passaic and Raritan River drainage areas encompass parts of several physiographic provinces.
Median concentrations of copper, chromium, lead, and zinc were highest in streambed-sediment samples from the New England (glaciated) Physiographic Province (figure 3). Results of Tukey's test showed that the concentrations of these trace elements were significantly higher in samples from the New England (glaciated) province that in those from the Valley and Ridge, New England, and Coastal Plain provinces (fig. 3) Median concentrations in samples from the Piedmont and Piedmont (glaciated) provinces typically were between the two extremes and could be the same statistically as those in either Tukey group, depending on the trace element (fig. 3).
Median concentrations of copper, chromium, lead, and zinc were highest in streambed-sediment samples from the Rahway and Passaic River drainage areas (fig. 4). Concentrations in samples from these drainage areas were significantly higher than those in samples from the Great Egg Harbor/Mullica River, Salem River/Raccoon Creek, and Pequest River/Paulins Kill/Pohatcong Creek drainage areas (figure 4).
The median iron concentration was lowest (3,650 µg/g (micrograms per gram)) in streambed-sediment samples from the Coastal Plain Physiographic Province, but results of Tukey's test show that only the median iron concentrations in samples from the New England (glaciated) and Coastal Plain provinces differ significantly from each other (fig. 3). Median iron concentrations in samples from the other provinces were not significantly different from those in samples from either the Coastal Plain or New England (glaciated) province (figure 3).
Results of Tukey's test show that the median iron concentration in streambed-sediment samples from the Great Egg Harbor/Mullica River drainage area (1,000 µg/g) was significantly lower than those in samples from the other drainage areas. Median iron concentrations in samples from the other drainage areas ranged from 4,600 µg/g for the Pequest River/Paulins Kill/Pohatcong Creek drainage area to 8,700 µg/g for the Salem River/Raccoon Creek drainage area, but these concentrations are not significantly different from one another (figure 4).
The median manganese concentration was lowest (23.5 µg/g) in streambed-sediment samples from the Coastal Plain Physiographic Province. Results of Tukey's test indicate that the median manganese concentration in sediments from the Coastal Plain is significantly lower than those in sediments from all the other physiographic provinces (fig. 3). Median manganese concentration was lowest (4.0 µg/g) in streambed sediments from the Great Egg Harbor/Mullica River drainage areas and highest (280 µg/g) in those from the Raritan and Pequest River/Paulins Kill/Pohatcong Creek drainage areas. Results of Tukey's test show that median manganese concentrations for the Great Egg Harbor/Mullica River and Big Timber/Cooper River drainage areas are significantly lower than those for all of the other drainage areas (figure 4).
Concentrations of arsenic in streambed sediments are generally lower and show a smaller range than those of other trace elements. Results of Tukey's test show that the median concentrations in streambed- sediment samples from the New England (glaciated), Coastal Plain, and Piedmont Physiographic Provinces were significantly higher than those in samples from the Piedmont (glaciated) and New England Provinces. Median concentrations of arsenic ranged from 0.8 µg/g for the Rahway River drainage area to 2.0 µg/g for the Raritan River and Salem River/Raccoon Creek drainage areas. Although median concentration of arsenic was lowest in samples from the Rahway River drainage area, median concentrations of most of the other trace elements were higher in samples from the Rahway River drainage area than in those from all the other drainage areas. Results of Tukey's test, however, did not distinguish among the drainage areas with respect to median concentrations of arsenic.
Median nickel concentrations were lowest in streambed-sediment samples from the New England and Coastal Plain Physiographic Provinces (3.1 and 3.4 µg/g, respectively) and highest in those from the New England (glaciated) and Piedmont (glaciated) provinces (10.0 µg/g). Tukey's test results show that only median nickel concentrations in samples from the Coastal Plain and New England provinces differ significantly from those in samples from the New England (glaciated), Piedmont, and Piedmont (glaciated) provinces (figure 3). Median nickel concentrations were lowest in samples from the Great Egg Harbor/Mullica River (2.5 µg/g) and Big Timber Creek/Cooper River (3.1 µg/g) drainage areas and highest in those from the Rahway and Passaic River drainage areas (10.0 µg/g). Tukey's test identified four groups, but none was significantly different from all the others (figure 4).
Overall, where significant differences in median trace element concentrations were present among the physiographic provinces, streambed sediments from the New England (glaciated) and Piedmont provinces generally contained higher concentrations of trace elements than those from the other provinces. High concentrations in sediments from the New England (glaciated) province reflect the presence of extensive magnetite deposits previously mined for iron ore. High concentrations in sediments from the Piedmont (glaciated) province reflect the high population density and percentage of urban land use in the province (table 1). The Piedmont (glaciated) province placed in the Tukey group with the highest median concentrations of chromium, copper, lead, and zinc, but was not in the Tukey group with highest median concentrations of arsenic, suggesting that the urban environment is a less important source of arsenic than of chromium, copper, lead, and zinc.
Where significant differences in median trace element concentrations were present among the basins, streambed sediments from the Rahway and Passaic River drainage areas, the most highly urbanized drainage areas, generally contained higher concentrations of trace elements than those from the other basins. The Great Egg Harbor/Mullica River drainage area, the least developed of the drainage areas, had significantly lower trace-element concentrations in streambed sediments than the other drainage areas (figure 4).
Fields, T.W., McNevin, T.F., Harkov, R.A, and Hunter, R.A.,1993, A summary of selected soil constituents and contaminants at background locations in New Jersey: New Jersey Department of Environmental Protection, 43 p.
Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in water resources: New York, Elsevier, 522 p.
Leahy, P.P., Rosenshein, J.S., and Knopman, D.S., 1990, Implementation plan of the National Water-Quality Assessment program: U.S. Geological Survey Open-File Report 90-174, 10 p.
Stackelburg, P.E., 1996, Presence and distribution of chlorinated organic compounds in streambed sediments, New Jersey: U.S. Geological Survey Fact Sheet-118-96.
U.S. Bureau of the Census, 1991, Census of population and housing, 1990: Public Law 94-171 data for New Jersey: Washington, D.C., U.S. Bureau of the Census, machine-readable data files (CD-ROM).
Information related to NAWQA can be obtained from:
NAWQA Project Chief, USGS
810 Bear Tavern Road, Suite 206
West Trenton, New Jersey 08628
phone 609-771-3943
