In cooperation with the Southern Division Naval Facilities Engineering Command
Chemical Quality of Water, Sediment, and Fish in Mountain Creek Lake, Dallas, Texas, 1994–97
By P.C. Van Metre, S.A. Jones, J. Bruce Moring, B.J. Mahler, and Jennifer T. Wilson
U.S. Geological Survey
Water-Resources Investigations Report 03–4082
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Contents
Abstract
Introduction
Purpose and Scope
Acknowledgments
Methods
Site Selection
Fish Taxa and Tissue Selection
Sampling Methods
Analytical Methods
Quality Control
Potential Sources of Contamination From Navy Facilities to Mountain Creek Lake
NWIRP Sources
NAS Sources
Chemical Quality of Water, Sediment, and Fish in Mountain Creek Lake
Reference Concentrations
Dating Sediment Cores
Occurrence, Trends, and Sources of Metals
Metals in Stormwater
Metals in Lake Water
Metals in Sediment
Metals in Fish
Sources of Metals
Occurrence, Trends, and Sources of Volatile Organic Compounds
VOCs in Stormwater
VOCs in Lake Water
VOCs in Sediment
VOCs in Fish
Sources of VOCs
Occurrence, Trends, and Sources of Polycyclic Aromatic Hydrocarbons
PAHs in Stormwater and Lake Water
PAHs in Sediment
PAHs in Fish
Sources of PAHs
Pyrogenic Versus Uncombusted Fuel Sources
Spatial Sources of PAHs
Occurrence, Trends, and Sources of Organochlorine Pesticides
Organochlorine Pesticides in Stormwater and Lake Water
Organochlorine Pesticides in Sediment
Organochlorine Pesticides in Fish
Sources of Organochlorine Pesticides
Occurrence, Trends, and Sources of Polychlorinated Biphenyls
PCBs in Stormwater
PCBs in Sediment
PCBs in Fish
Sources of PCBs
Sediment and Contaminant Accumulation in Cottonwood Bay
Summary
References
Figures
1–2. |
Maps showing: | |
1. |
Locations of Phase I sampling sites and media collected at Mountain Creek Lake, Dallas, Texas | |
2. |
Locations of Phase II sampling sites and media collected at Mountain Creek Lake, Dallas, Texas | |
3–5. |
Boxplots showing: | |
3. |
Percent recovery of laboratory spiked quality-control samples for polycyclic aromatic hydrocarbons in bottom sediment collected at Mountain Creek Lake, Dallas, Texas | |
4. |
Percent differences between environmental and replicate samples in lake bottom sediment collected at Mountain Creek Lake, Dallas, Texas | |
5. |
Percent recovery of laboratory spiked quality-control samples for organochlorine pesticides in fish tissue collected at Mountain Creek Lake, Dallas, Texas | |
6–8. |
Maps showing: | |
6. |
Locations of selected buildings, groups, and solid-waste management units (SWMUs) on the Naval Air Station and Naval Weapons Industrial Reserve Plant, Dallas, Texas | |
7. |
Place names of parts of Mountain Creek Lake used in this report | |
8. |
Locations of sites and range in selected constituents in bottom sediments for clusters | |
9. |
Graphs showing cesium-137 and organochlorine pesticide concentrations in M2.40 and MCL–4 cores | |
10. |
Graphs showing age-depth indicators in Bay–13 core | |
11–15. |
Graphs showing: | |
11. |
Ratios of Phase I metal concentrations in lake bottom sediment at selected sites to mean concentrations of main-lake reference sites | |
12. |
Ratios of Phase II metal concentrations in lake bottom sediment at selected sites to mean concentrations of main-lake reference sites | |
13. |
Trends in chromium, lead, and zinc concentrations in MCL–4, M2.40, and Bay–13 cores | |
14. |
Trends in heavy metals concentrations in Cottonwood Bay as indicated by the Bay–13 core | |
15. |
Trends in mercury concentrations in the NAS inlet as indicated by the M2.40 core | |
16. |
Boxplots showing distribution of metal concentrations in fish tissues, Mountain Creek Lake | |
17. |
Graphs showing ratios of lake-bottom sediment and suspended sediment metal concentrations in the west lagoon and Cottonwood Bay to mean concentrations of mean-lake reference sites | |
18. |
Graph showing percent detections of volatile organic compounds in composite samples collected at the fixed stormwater sites, Naval Air Station and Naval Weapons Industrial Reserve Plant | |
19. |
Boxplots showing distribution of BTEX compound concentrations detected at NAS–2 stormwater site | |
20. |
Graphs showing volatile organic compound concentrations in lake water samples | |
21. |
Maps showing fluoranthene concentrations in top 3 centimeters of lake bottom sediments from (a) Phase I sampling; (b) Phase II sampling; (c) Phase II Cottonwood Bay sampling; and (d) Phase II NAS inlet sampling | |
22. |
Map showing total PAH concentrations in top 3 centimeters of surficial sediment from Phase II sampling | |
23. |
Boxplots showing distribution of benzo(a)pyrene and benzo(b)fluoranthene concentrations in top 3 centimeters of surficial sediment | |
24. |
Graphs showing trends in PAH concentrations in Bay–13, MCL–7, and MCL–4 cores | |
25. |
Graphs showing trends in PAH concentrations in M2.40 core in the NAS inlet | |
26. |
Boxplots showing longitudinal variation in total PAH and source indicator ratios for surficial sediment samples | |
27. |
Boxplots showing comparison of lake-bottom sediment and suspended sediment PAH concentrations in the east and west lagoons and Cottonwood Bay | |
28. |
Graphs showing mean concentrations of organochlorine pesticides detected in composite fish tissues sampled in Phase I | |
29. |
Boxplots showing distribution of organochlorine pesticide concentrations detected in fish sampled in Phase II | |
30. |
Maps showing PCB concentrations in top 3 centimeters of lake bottom sediment from (a) Phase I sampling; (b) Phase II sampling; (c) Phase II Cottonwood Bay sampling; and (d) Phase II NAS inlet sampling | |
31. |
Graphs showing trends in PCB concentrations in Mountain Creek Lake (cores MCL–4, M2.40, Bay–13) and in White Rock Lake, Dallas Texas | |
32. |
Boxplots showing distribution of PCB concentrations in fish tissues | |
33. |
Map showing thickness of lacustrine sediment in central and east Cottonwood Bay | |
34. |
Graphs showing mass accumulation rates of silver in Bay–13 core |
Tables
1. |
Type and number of samples analyzed for selected constituents at Mountain Creek Lake, Dallas, Texas |
2. |
Results of fishing-habits survey on Mountain Creek Lake |
3. |
Waste disposed of in the West Lagoon Naval Weapons Industrial Reserve Plant |
4. |
Sites included in cluster analysis |
5. |
Summary of selected metal concentrations in sediment |
6. |
Comparison of volatile organic compound concentrations at the Navy sites, Dallas, Texas, and at industrial sites in the Dallas-Fort Worth area |
7. |
Polycyclic aromatic hydrocarbon concentrations in stormwater suspended sediment samples |
8. |
Diagnostic polycyclic aromatic hydrocarbon ratios for selected surficial sediment samples |
9. |
Reported and estimated total polycyclic aromatic hydrocarbon concentrations for east and west lagoon sediment |
10. |
Organochlorine pesticide and polychlorinated biphenyl concentrations in stormwater suspended sediment samples |
11. |
Summary of total polychlorinated biphenyl concentrations in sediment |
12. |
Estimated total and annual contaminant mass accumulations in east and central Cottonwood Bay |
Abstract
The occurrence, trends, and sources of numerous inorganic and organic contaminants were evaluated in Mountain Creek Lake, a reservoir in Dallas, Texas. The study, done in cooperation with the Southern Division Naval Facilities Engineering Command, was prompted by the Navy’s concern for potential off-site migration of contaminants from two facilities on the shore of Mountain Creek Lake, the Naval Air Station Dallas and the Naval Weapons Industrial Reserve Plant. Sampling of stormwater (including suspended sediment), lake water, bottom sediment (including streambed sediment), and fish was primarily in Mountain Creek Lake but also was in stormwater outfalls from the Navy facilities, nearby urban streams, and small streams draining the Air Station.
Volatile organic compounds, predominantly solvents from the Reserve Plant and fuel-related compounds from the Air Station, were detected in stormwater from both Navy facilities. Fuel-related compounds also were detected in Mountain Creek Lake at two locations, one near the Air Station inlet where stormwater from a part of the Air Station enters the lake and one at the center of the lake. Concentrations of volatile organic compounds at the two lake sites were small, all less than 5 micrograms per liter.
Elevated concentrations of cadmium, chromium, copper, lead, mercury, nickel, silver, and zinc, from 2 to 4 times concentrations at background sites and urban reference sites, were detected in surficial bottom sediments in Cottonwood Bay, near stormwater outfalls from the Reserve Plant.
Elevated concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls, compared to background and urban reference sites, were detected in surficial sediments in Cottonwood Bay. Elevated concentrations of polycyclic aromatic hydrocarbons, indicative of urban sources, also were detected in Cottonwood Creek, which drains an urbanized area apart from the Navy facilities. Elevated concentrations of polychlorinated biphenyls were detected in two inlets near the Air Station shoreline. Polycyclic aromatic hydrocarbon and heavy metal concentrations near the Air Station shoreline were not elevated compared to urban reference sites.
Much larger concentrations of selected heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls were detected in deeper, older sediments than in surficial sediments in Cottonwood Bay. The decreases in concentrations coincide with changes in wastewater discharge practices at the Reserve Plant. Elevated concentrations of polycyclic aromatic hydrocarbons and polychlorinated biphenyls also were detected in older sediments in the Air Station inlet.
On the basis of dated sediment cores and contaminant discharge histories, contaminant accumulation rates in Cottonwood Bay were much greater historically than recently. Most heavy metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls that accumulated in the central and eastern parts of Cottonwood Bay appear to have come from the west lagoon on the Reserve Plant. Treated sewage and industrial-process wastewater were discharged to the west lagoon from about 1941 to 1974. Estimated annual contaminant accumulation rates in Cottonwood Bay decreased by from 1 to 2 orders of magnitude after 1974, when most point-source discharges to the west lagoon ceased.
Polychlorinated biphenyls were detected in 61 of 62 individual fish-tissue
samples. The largest average concentrations were in eviscerated channel catfish
and the smallest were in largemouth bass fillets. Polychlorinated biphenyl and
selenium concentrations from analyses of this study were large enough to prompt
the Texas State Department of Health to issue a fish-possession ban for Mountain
Creek Lake in 1996.
Suspended sediments in stormwater at the lagoon outfalls and at sites on Cottonwood
Creek were sampled and analyzed for major and trace elements, polycyclic aromatic
hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls. The
suspended sediments from the outfalls contained about the same mixture of heavy
metals and organic compounds, in elevated concentrations compared to reference
sites, as bottom sediments from the lagoons and surficial bottom sediments in
Cottonwood Bay.
Diagnostic ratios of polycyclic aromatic hydrocarbons indicate that uncombusted fuel sources contribute to older sediments and that pyrogenic sources of polycyclic aromatic hydrocarbons dominate recently deposited sediments in Cottonwood Bay and along the Air Station shoreline.
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