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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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