National Water-Quality Assessment Program
Collection, Analysis, and Age-Dating of Sediment Cores From 56 U.S. Lakes and Reservoirs Sampled by the U.S. Geological Survey, 1992–2001
By Peter C. Van Metre, Jennifer T.
Wilson, Christopher C. Fuller, Edward Callender, and
Barbara J. Mahler
U.S. Geological Survey
Scientific Investigations Report 2004–5184
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Contents
Abstract
Introduction
Study Design
Collection of Cores
Selection of Coring Sites
Selection of Boat and Coring Tools
Coring
Subsampling and Description of Cores
Analysis of Cores
Major and Trace Elements
Organic Compounds
Radionuclides
Quality Assurance
Age-Dating of Cores
Mass Accumulation Rates
Using Cesium-137 to Assign Dates
Using Lead-210 to Assign Dates
Exponentially Decreasing Mass Accumulation Rates
Rating the Reliability of Age Dates
Age Assignments for Cores
Factors Affecting the Reliability of Age-Dating
Interpreting Sediment Cores From Lakes and Reservoirs
Differences Between Lakes and Reservoirs and Implications for Paleolimnology
Understanding Fluvial and Atmospheric Contaminant Inputs
Summary
References
Appendix
Hillstrand Pond, Alaska
Westchester Lagoon, Alaska
Lake Ballinger, Wash.
Tolt Reservoir, Wash.
Lake Washington, Wash.
West Street Basin, Calif.
R.R. Canyon Lake, Calif.
Lake Hemet, Calif.
Sweetwater Reservoir, Calif.
Lake Mead, Nev./Ariz.
Great Salt Lake, Utah
Decker Lake, Utah
Red Butte Reservoir, Utah
Dillon Reservoir, Colo.
Sloans Lake, Colo.
Cherry Creek Reservoir, Colo.
Lake Como, Tex.
Fosdic Lake, Tex.
White Rock Lake, Tex.
Echo Lake, Tex.
Town Lake, Tex.
Lorence Creek Lake, Tex.
Lake Houston, Tex.
Lake Livingston, Tex.
Palmer Lake, Minn.
Lake Harriet, Minn.
Lake in the Hills, Ill.
Shoe Factory Road Pond, Ill.
Busse Lake, Ill.
Beck Lake, Ill.
Lake Sidney Lanier, Ga.
Berkeley Lake, Ga.
Lakewood Park Lake, Ga.
Panola Lake, Ga.
West Point Lake, Ga.
Lake Harding, Ga./Ala.
Lake Blackshear, Ga.
Lake Walter F. George, Ga./Ala.
Lake Seminole, Ga./Fla.
Sand Lake, Fla.
Lake Orlando, Fla.
Lake Killarney, Fla.
Lake Anne, Va.
Fairfax Lake, Va.
Clyde Potts Reservoir, N.J.
Orange Reservoir, N.J.
Packanack Lake, N.J.
Newbridge Pond, N.Y.
Big Round Top Pond, R.I.
Maple Street Pond, Mass.
Harris Pond, Mass.
Upper Mystic Lake, Mass.
Charles River, Mass.
South Reservoir, Mass.
Basin Brook Pond, N.H.
Crocker Pond, Maine
Figures
| 1. | Map showing locations of National Water-Quality Assessment Program Reconstructed Trends National Synthesis study lake sediment coring sites, 1992–2001 | |
| 2–4. | Photographs showing: | |
| 2. | (a) Pontoon boat with A-frame used to collect sediment cores in large lakes, and (b) Zodiac raft with crane and hand-operated winch used to collect sediment cores in smaller lakes | |
| 3. | U.S. Geological Survey personnel (a) describing a gravity core, (b) placing gravity core in core extrusion stand, and (c) slicing a subsample from a gravity core | |
| 4. | U.S. Geological Survey personnel subsampling a box core | |
| 5. | Example of a plot used for lead-210 age-dating using the constant flux, constant sedimentation rate (CF:CS) model | |
| 6. | Graph showing comparison of average mass accumulation rate (MAR) computed using three date-depth markers to an exponentially decreasing MAR modeled using the approach of Callender and Robbins (1993) | |
| 7. | Example of cesium-137 profile in a sediment core (Maple Street Pond, Mass.) with postdepositional mixing or desorption and diffusion, or both | |
| 8. | Graphs showing the percentage of lakes receiving “good,” “fair,” and “poor/none” age-dating ratings when grouped by core mass accumulation rate (MAR), water-body type, watershed land use, and watershed area | |
Tables
| 1. | List of publications with interpretations of chemical trends in selected lakes presented in this report |
| 2. | Basic characteristics of lakes described in this report |
| 3. | Summary of the relative percent difference (RPD) of duplicate analyses for selected constituents |
| 4. | Comparison of DryMass computations using measured bulk density versus an assumed bulk density of 2.5 grams per cubic centimeter for box core BRT.B1 collected from Big Round Top Pond, R.I. |
| 5. | Summary of age date ratings presented in this report |
Abstract
The U.S. Geological Survey Reconstructed Trends National Synthesis study collected sediment cores from 56 lakes and reservoirs between 1992 and 2001 across the United States. Most of the sampling was conducted as part of the National Water-Quality Assessment (NAWQA) Program. The primary objective of the study was to determine trends in particle-associated contaminants in response to urbanization; 47 of the 56 lakes are in or near one of 20 U.S. cities. Sampling was done with gravity, piston, and box corers from boats and push cores from boats or by wading, depending on the depth of water and thickness of sediment being sampled. Chemical analyses included major and trace elements, organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, cesium-137, and lead-210. Age-dating of the cores was done on the basis of radionuclide analyses and the position of the pre-reservoir land surface in the reservoir and, in a few cases, other chemical or lithologic depth-date markers. Dates were assigned in many cores on the basis of assumed constant mass accumulation between known depth-date markers. Dates assigned were supported using a variety of other date markers including first occurrence and peak concentrations of DDT and polychlorinated biphenyls and peak concentration of lead. A qualitative rating was assigned to each core on the basis of professional judgment to indicate the reliability of age assignments. A total of 122 cores were collected from the 56 lakes and age dates were assigned to 113 of them, representing 54 of the 56 lakes. Seventy-four of the 122 cores (61 percent) received a good rating for the assigned age dates, 28 cores (23 percent) a fair rating, and 11 cores (9 percent) a poor rating; nine cores (7 percent) had no dates assigned. An analysis of the influence of environmental factors on the apparent quality of age-dating of the cores concluded that the most important factor was the mass accumulation rate (MAR) of sediment: the greater the MAR, the better the temporal discretization in the samples and the less important the effects of postdepositional sediment disturbance. These age-dated sediment cores provide the basis for local-, regional-, and national-scale interpretations of water-quality trends.
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