U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2010–5076

In cooperation with the Lockheed Martin Corporation

Polychlorinated Biphenyls in Suspended-Sediment Samples 

from Outfalls to Meandering Road Creek at Air Force Plant 4, 

Fort Worth, Texas, 2003–08
Front cover:

Top left, Pumping two suspended-sediment samples during filtration for organic analyses, 2006. 

Top right, Churning and pumping a suspended-sediment sample during filtration for organic 

analyses, 2003. 

Bottom, Filtering a suspended-sediment sample to isolate sediments for organics analyses, 2006. 
Polychlorinated Biphenyls in SuspendedSediment Samples from Outfalls to 

Meandering Road Creek at Air Force 

Plant 4, Fort Worth, Texas, 2003–08

By Christopher L. Braun and Jennifer T. Wilson

In cooperation with the Lockheed Martin Corporation

Scientific Investigations Report 2010–5076

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Braun, C.L., and Wilson, J.T., 2010, Polychlorinated biphenyls in suspended-sediment samples from outfalls to 

Meandering Road Creek at Air Force Plant 4, Fort Worth, Texas, 2003–08: U.S. Geological Survey Scientific 

Investigations Report 2010–5076, 20 p. 
iii

Acknowledgments

The authors thank Lockheed Martin Corporation personnel at U.S. Air Force Plant 4 in 

Fort Worth, Texas, for providing access to the sampling sites.
Blank Page
v

Contents

Abstract ..........................................................................................................................................................1

Introduction ....................................................................................................................................................1

Purpose and Scope .............................................................................................................................3

Site Background and Description of Study Area ...........................................................................3

Polychlorinated Biphenyls .................................................................................................................5

Description of Previous Studies ........................................................................................................5

Engineering Controls Used to Alleviate Polychlorinated Biphenyl Contamination at 

Air Force Plant 4 .....................................................................................................................7

Approach ........................................................................................................................................................7

Collection and Processing of Suspended-Sediment Samples .....................................................7

Analytical Methods ..............................................................................................................................7

Quality Control ......................................................................................................................................8

Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering 

Road Creek .......................................................................................................................................8

Summary .......................................................................................................................................................11

References Cited .........................................................................................................................................12

Appendixes 

1. Concentrations of selected polychlorinated biphenyl congeners in suspendedsediment samples collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, 

Texas, 2003–07 ............................................................................................................................17

2. Concentrations of antibacterial, antifungal, pesticide, and flame retardant 

compounds in suspended-sediment samples collected from outfalls 4 and 5, Air 

Force Plant 4, Fort Worth, Texas, 2008 ...................................................................................18

Figures

1–2. Maps showing: 

1. Location of Meandering Road Creek, Woods Inlet of Lake Worth, and Air 

Force Plant 4, Fort Worth, Texas ......................................................................................2

2. Suspended-sediment sampling sites, storm drainage areas for outfalls 4 and 

5, areas of known or suspected polychlorinated biphenyl (PCB) releases, 

former landfills, and areas where engineering controls (asphalt cap areas 

and sweeping) were implemented to potentially alleviate PCB contamination 

at Air Force Plant 4, Fort Worth, Texas, 2003–08 ...........................................................4

3–4. Graphs showing: 

3. Ratios of total polychlorinated biphenyl (PCB) concentrations (sum of 18 

reported congeners [∑PCBc]) to threshold effect concentration, a consensusbased sediment-quality guideline for PCBs, for suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2003–08 ........9

4. Ratio of individual polychlorinated biphenyl (PCB) congener concentrations 

to sum of 10 selected PCB congeners for suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2003–08 ......10
vi

Table

1. Concentrations of polychlorinated biphenyls in suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2008 .......................6

Conversion Factors, Datum, and Sediment-Quality Units

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

kilometer (km) 0.6214 mile (mi)

meter (m) 3.281 foot (ft) 

Area

square meter (m2

) 10.76 square foot (ft2)

Volume

liter (L) 33.82 ounce, fluid (fl. oz)

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

Pressure

kilopascal (kPa) 0.1450 pound per square inch (lb/in2

) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

 °F=(1.8×°C)+32

Datum

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Sediment-Quality Units 

Chemical compound concentrations are reported in micrograms per kilogram (μg /kg), a unit 

expressing the concentration of a chemical compound as weight (micrograms) per unit volume 

(kilogram) of sediment. 
Abstract 

Meandering Road Creek is an intermittent stream and 

tributary to Lake Worth, a reservoir on the West Fork Trinity River on the western edge of Fort Worth, Texas. U.S. Air 

Force Plant 4 (AFP4) is on the eastern shore of Woods Inlet, 

an arm of Lake Worth. Meandering Road Creek gains inflow 

from several stormwater outfalls as it flows across AFP4. 

Several studies have characterized polychlorinated biphenyls 

(PCBs) in the water and sediments of Lake Worth and Meandering Road Creek; sources of PCBs are believed to originate 

primarily from AFP4. Two previous U.S. Geological Survey 

(USGS) reports documented elevated PCB concentrations 

in surficial sediment samples from Woods Inlet relative to 

concentrations in surficial sediment samples from other parts 

of Lake Worth. The second of these two previous reports also 

identified some of the sources of PCBs to Lake Worth. These 

reports were followed by a third USGS report that documented 

the extent of PCB contamination in Meandering Road Creek 

and Woods Inlet and identified runoff from outfalls 4 and 5 at 

AFP4 as prominent sources of these PCBs. 

This report describes the results of a fourth study by the 

USGS, in cooperation with the Lockheed Martin Corporation, to investigate PCBs in suspended-sediment samples in 

storm runoff from outfalls 4 and 5 at AFP4 following the 

implementation of engineering controls designed to potentially 

alleviate PCB contamination in the drainage areas of these 

outfalls. Suspended-sediment samples collected from outfalls 

4 and 5 during storms on March 2 and November 10, 2008, 

were analyzed for selected PCBs. Sums of concentrations of 

18 reported PCB congeners (∑PCBc

) in suspended-sediment 

samples collected before and after implementation of engineering controls are compared. At both outfalls, the ∑PCBc

before engineering controls was higher than the ∑PCBc after 

engineering controls. The ∑PCBc in suspended-sediment 

samples collected at AFP4 before and after implementation 

of engineering controls also is compared to the threshold 

effect concentration (TEC), the concentration below which 

adverse effects to benthic biota rarely occur. ∑PCBc exceeded 

the TEC for 75 percent of the samples collected at outfall 4 

and 67 percent of the samples collected at outfall 5 before 

the implementation of engineering controls. ∑PCBc

 did not 

exceed the TEC in samples collected at either outfall 4 or outfall 5 after the implementation of engineering controls.

The relative prominence of 10 selected PCB congeners 

was evaluated by graphical analysis of ratios of individual 

concentrations of the 10 PCB congeners to the sum of these 

PCB congeners. An overall decrease in concentrations of PCB 

congeners at outfalls 4 and 5 after implementation of engineering controls, as well as a shift in prominence from lighter, less 

chlorinated congeners to a heavier, more chlorinated congener 

might have resulted from the implementation of engineering 

controls. Because of the small number of samples collected 

and lack of runoff and precipitation data to evaluate comparability of sampling conditions before and after implementation 

of engineering controls, all conclusions are preliminary.

Introduction

Meandering Road Creek is an intermittent stream and 

tributary to Lake Worth, a reservoir on the West Fork Trinity 

River on the western edge of Fort Worth, Tex. U.S. Air Force 

Plant 4 (AFP4) is on the eastern shore of Woods Inlet, an arm 

of Lake Worth that extends south from the main body of the 

lake, east of Interstate Highway 820 (fig. 1). Meandering 

Road Creek gains inflow from several stormwater outfalls 

on AFP4 as the creek flows to its terminus at Woods Inlet. 

Because of groundwater contamination, AFP4 was placed on 

the National Priorities List of hazardous waste sites in 1990 

(U.S. Environmental Protection Agency, 1990). In spring 

2000, the Texas Department of Health issued a fish consumption advisory for Lake Worth because of elevated concentrations of polychlorinated biphenyls (PCBs) in the edible tissues 

of selected species of fish (Texas Department of State Health 

Services, 2010). PCBs are hydrophobic organic contaminants 

that sorb strongly to organic matter and particulates; detection 

of PCBs is common in urban lake and reservoir sediments 

(Van Metre, Callender, and Fuller, 1997; Van Metre and others, 1998; Long and others, 2003). The occurrence of PCBs 

in fish led to several investigations by the U.S. Geological 

Survey (USGS) in cooperation with the U.S. Air Force to 

Polychlorinated Biphenyls in Suspended-Sediment 

Samples from Outfalls to Meandering Road Creek at 

Air Force Plant 4, Fort Worth, Texas, 2003–08

By Christopher L. Braun and Jennifer T. Wilson
2 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

Figure 1. Location of Meandering Road Creek, Woods Inlet of Lake Worth, and Air Force Plant 4, Fort Worth, Texas. 

Air Force Plant 4

(AFP4)

Woods Inlet

Lake Worth

West

Fork

River

Trinity

Creek

Road

Meandering

IH-820

Base from U.S. Air Force, Aeronautical Systems Center

32o46'

32o47'

97o27' 97o26' 97o25'

0 0.25 0.5 MILE

0 0.25 0.5 KILOMETER

AFP4 boundary

EXPLANATION

Boundary of area shown in figure 2

§ ̈¦ § ̈¦45 35E

§ ̈¦20

§ ̈¦635 § ̈¦820

§ ̈¦30

§ ̈¦35

§ ̈¦35

§ ̈¦35W

§ ̈¦20 Fort Worth

Dallas

Lake

 Worth

TEXAS

Area enlarged
Introduction 3

characterize sediment-associated contaminants, including 

PCBs, in the lake-bottom, streambed, and suspended sediments of Lake Worth, Woods Inlet, Meandering Road Creek, 

and the stormwater outfalls at AFP4 that drain to Meandering Road Creek (Harwell and others, 2003; Besse and others, 

2005; Braun and others, 2008). Lighter, more volatile PCBs 

have fewer chlorine atoms attached and are less chlorinated, 

whereas heavier, less volatile PCBs have more chlorine atoms 

attached and are more chlorinated (Ockenden and others, 

1998). Selected PCBs were analyzed in lake-bottom sediment 

samples collected from Lake Worth and in streambed and 

suspended-sediment samples collected from Meandering Road 

Creek (a tributary to Lake Worth) at AFP4 and from outfalls 

that drain to Meandering Road Creek. On the basis of PCB 

concentrations measured in suspended-sediment samples, outfalls 4 and 5 at AFP4 were identified as two prominent sources 

of PCBs in Meandering Road Creek (Braun and others, 2008). 

Engineering controls were implemented in late 2007 and early 

2008, from about November 2007 through February 2008, 

to potentially alleviate PCB contamination in the drainage 

areas of outfalls 4 and 5. This report, the fourth USGS study, 

was done in cooperation with the Lockheed Martin Corporation. The study investigated the concentration of PCBs in 

suspended-sediment samples in storm runoff from outfalls 4 

and 5 at AFP4 following the implementation of engineering 

controls in the drainage areas of these outfalls and compared 

the measured concentrations to results from previous USGS 

studies at the site and to applicable threshold effect concentration (TEC) guidelines. 

Purpose and Scope

This report describes concentrations of PCB congeners 

measured in suspended-sediment samples collected from 

outfalls 4 and 5 at AFP4 during 2003–08. PCB concentrations measured in suspended-sediment samples collected from 

outfalls 4 and 5 during 2003–07 for previous USGS studies at AFP4, before implementation of engineering controls 

designed to potentially alleviate PCB contamination in the 

drainage areas of outfalls 4 and 5, are compared to PCB concentrations measured in suspended-sediment samples collected 

from outfalls 4 and 5 during periods of runoff on March 2 

and November 10, 2008, after implementation of engineering 

controls.

Concentrations of PCB congeners are compared to TECs 

described in consensus-based sediment-quality guidelines. 

Concentrations of PCB congeners were normalized to compare relative distributions of PCB congeners from the different 

samples. In this report, a subset of 18 of the 27 PCB congeners 

that were analyzed in samples collected from outfalls 4 and 5 

in previous USGS studies at AFP4 were quantified and compared to the same 18 PCB congeners quantified in samples 

collected in 2008. The relative prominence of lighter and 

heavier (more and less volatile, respectively) PCB congeners 

before and after implementation of engineering controls are 

also described. No discharge measurements were made at the 

outfalls in Meandering Road Creek during the periods of 

runoff when samples were collected, and no precipitation 

data were collected to quantify the concentrations of PCB 

congeners in the suspended-sediment samples on the basis of 

discharge amounts or storm intensity. Because of the small 

number of samples collected and lack of runoff and precipitation data to evaluate comparability of sampling conditions 

before and after implementation of engineering controls, all 

conclusions are preliminary.

Site Background and Description of Study Area

AFP4 has manufactured military aircraft since 1942 

on land adjacent to Woods Inlet of Lake Worth in Fort 

Worth and is currently (2009) in the remedial action phase 

of the Superfund process (U.S. Environmental Protection 

Agency, 2009). Waste materials containing PCBs were 

generated at the plant and likely placed in on-site landfills 

or burned in fire-training exercises prior to 1973 (Texas 

Department of Health, 1998). Areas of known and suspected 

PCB releases are described in detail in Braun and others 

(2008), including a transformer failure in March 1984 in an 

electrical substation, which resulted in the leakage of PCBs 

adjacent to building 14 (fig. 2; area 014PCBLK3). Surfacewater runoff from the area near the PCB leak at building 14 

either discharges to Meandering Road Creek at outfall 4 or 

collects in a storm-sewer line that ultimately discharges to 

Meandering Road Creek at outfall 4 (fig. 2). In March 1989, 

PCBs were discovered to have leaked beneath a concrete 

slab inside building 5 (fig. 2; area 005PCBLK1). Storm-sewer 

lines intersecting the PCB leak at building 5 discharge to 

outfalls 4 and 5 (fig. 2). PCBs also might have been released 

from Fire Department Training Area 2 (FDTA2), a 15-meterdiameter earthen ring (RUST Geotech, 1995) west of building 

15 used for semiannual fire training exercises between 1955 

and 1965; FDTA2 might have been used for disposal of waste 

oils and fuels containing PCBs (CH2M Hill, 1984). FDTA2 

is next to a storm-sewer line that discharges to Meandering 

Road Creek at outfall 4. Some of the surface-water runoff 

from FDTA2 collects in a storm-sewer line that eventually 

discharges to Meandering Road Creek at outfall 4. Because 

FDTA2 is in the drainage area of outfall 5, the rest of the 

runoff from FDTA2 discharges to Meandering Road Creek at 

outfall 5.

Historical landfills 1 and 3 on opposite sides of Bomber 

Road (fig. 2) are another suspected source of PCB releases. 

These landfills were used to dispose of potentially hazardous wastes including used oils, solvents, thinners, paint, and 

unspecified liquid waste (International Technology Corporation, 2001). In 1966, landfill 1 was closed, and the area 

was graded and paved to make the west parking lot (fig. 2). 

Landfill 3 is on the east bank of Meandering Road Creek on 

the west side of Bomber Road (fig. 2). Landfills 1 and 3 provide surface-water runoff and groundwater seepage to Meandering Road Creek; remediation work to curtail runoff and 

groundwater seepage from these landfills began in the 1980s 
4 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

Figure 2. Suspended-sediment sampling sites, storm drainage areas for outfalls 4 and 5, areas of known or suspected polychlorinated 

biphenyl (PCB) releases, former landfills, and areas where engineering controls (asphalt cap areas and sweeping) were implemented to 

potentially alleviate PCB contamination at Air Force Plant 4, Fort Worth, Texas, 2003–08. 

X

X

X

X X X X X X X

X X

X

X X X X X X X X X X

X X X X X X

X

X X

X

X X X X X X X X X X X

X X X X X X X X X X X X X X X X X X X

X

X X X X

Concrete

block

fence

Base from Burns & McDonnell

Engineering Company, Inc.

Existing

chain-link fence

Electrical

substation

Building 5

0 0.1 0.2 MILE

0 0.1 0.2 KILOMETER

Base modified from U.S. Geological Survey

Digital orthophoto quarter-quadrangle,

Universal Transverse Mercator projection, Zone 14,

North American Datum of 1983, 0.3-meter resolution

Electrical substation

(inset shown at right)

Building

15

Building

14

Air Force

Plant 4

(AFP4)

West parking lot

Bomber Rd.

Meandering

Road

 Creek

Woods

Inlet

OF5A OF5B

OF4

Landfill 3

Landfill 1

014PCBLK3

005PCBLK1

FDTA2 32°46'30''

32°46'37.5''

32°46'22.5''

32°46'7.5''

32°46'15''

32°46'

97°27'22.5'' 97°27'15'' 97°27'07.5'' 97°27'

Storm drainage area for outfall 4

Storm drainage area for outfall 5

Storm drainage area for outfall 4 (Freese and 

Nichols, Inc., written commun., 2008)

Storm drainage area for outfall 5 (Freese and 

Nichols, Inc., written commun., 2008)

Unpaved area within outfall drainage

(includes electrical substation)

Grassy area within outfall drainage

Area where no sweeping occurred

Area where sweeping occurred

Area of known polychlorinated biphenyl

release (Earth Tech, Inc., 2005) 

EXPLANATION

FDTA2

Asphaltic concrete cap area

Building

Suspended-sediment sampling site and

outfall site identifier 

Storm-sewer line

Storm-sewer location (manhole or drain)

OF4

Concrete barricades

Railroad tracks

AFP4 boundary
Introduction 5

and is described in detail in Braun and others (2008). Further 

details about the known or suspected areas of PCB releases are 

included in Braun and others (2008). Meandering Road Creek 

borders AFP4 to the west and flows north to the Woods Inlet 

of Lake Worth. Historically, Meandering Road Creek received 

contaminated runoff from stormwater outfalls 4 and 5 (Besse 

and others, 2005; Braun and others, 2008). Outfall 4 receives 

runoff from several buildings and parking areas, including 

some of the area over landfill 1, and drains into Meandering Road Creek about 200 meters upstream from the point 

where Meandering Road Creek enters Woods Inlet. Outfall 5 

receives runoff from building 15 and parking areas and drains 

into Meandering Road Creek about 25 meters upstream from 

the point where Meandering Road Creek enters Woods Inlet 

(fig. 2). Additional site background information, including a 

more detailed history of PCB contamination studies at AFP4, 

is provided in Braun and others (2008).

Polychlorinated Biphenyls

PCBs are comprised of as many as 209 theoretically 

possible chlorinated compounds, called congeners, with 

various numbers and positions of chlorine atoms attached to 

the biphenyl structure. Each congener has been assigned a 

congener number; congener number increases generally with 

increasing chlorination of the biphenyl structure. Of the 209 

theoretically possible congeners, about 130 were widely used 

in commercial PCB mixtures (Erickson, 2001). Braun and others (2008) summarizes the development and use of PCBs and 

their adverse human health effects and association with cancer 

in humans and animals. 

In the samples collected for this study, the USGS 

National Water Quality Laboratory (NWQL), Denver, Colo., 

quantified 18 common PCB congeners of the 27 common PCB 

congeners quantified in Braun and others (2008). Total PCBs 

were calculated as the sum of the 18 quantified congeners 

(∑PCBc). Consistent with the treatment of nondetections of 

PCB congeners in previous USGS studies at AFP4 (Harwell 

and others, 2003; Besse and others, 2005; Braun and others, 

2008), nondetections of PCB congeners were treated as zeros; 

estimated concentrations were used at their reported values. 

Detection frequencies for the 18 PCB congeners analyzed in 

this report varied by the degree of chlorination; in general, 

detection frequency increased with increasing degree of chlorination (table 1).

Concentrations of total PCBs in suspended-sediment 

samples are compared to a consensus-based sedimentquality guideline developed for freshwater ecosystems by 

MacDonald and others (2000) to provide a general indication 

of the degree of contamination. The TEC (table 1) is the 

concentration below which adverse effects to benthic biota 

rarely occur (MacDonald and others, 2000). This sedimentquality guideline was derived through various laboratory, 

field, and theoretical methods and is neither definitive for 

determining sediment toxicity to benthic biota nor to be 

extrapolated to assess adverse effects to fish, aquatic plants, 

or humans (Long and others, 1995; MacDonald and others, 

2000). Although this sediment-quality guideline provides 

a general indication of the degree of contamination, it does 

not provide a benchmark for concern for accumulation in fish 

or for human health risk associated with eating fish.

Description of Previous Studies

A Preliminary Assessment/Site Inspection (PA/SI) and a 

Remedial Investigation/Feasibility Study (RI/FS) of the AFP4 

site began in October 1990 to characterize contamination of 

Lake Worth and its tributaries by PCBs and other organic 

contaminants (Braun and others, 2008), as well as to accomplish other objectives. Elevated concentrations of contaminants, such as PCBs, were detected in a small, inedible fish 

species (mosquito fish) during the PA/SI in July 1998. One 

conclusion of the PA/SI in July 1998 was that an indeterminate 

public health hazard existed in Lake Worth from exposure 

to contaminants through the food chain (Texas Department 

of Health, 1998). The Texas Department of Health (TDH) 

issued a fish-consumption advisory following fish sampling 

by the USGS (Moring, 2002) because the levels of PCBs 

detected in edible fish samples posed a “significant health 

risk” (Texas Department of State Health Services, 2010). A 

detailed description of the July 1998 TDH site evaluation and 

the Agency for Toxic Substances and Disease Registry (2001) 

site evaluation is provided in Moring (2002).The detection of 

PCBs and other organic contaminants in fish collected from 

Lake Worth and its tributaries led to three subsequent studies by the USGS in cooperation with the U.S. Air Force. In 

the first study, Lake Worth lake-bottom sediment samples 

were collected during 2000–2001 and analyzed for sedimentassociated contaminants, including PCBs (Harwell and others, 

2003). That study documented elevated PCB concentrations in 

surficial sediment in Woods Inlet relative to concentrations in 

surficial sediment in other parts of Lake Worth. This finding 

indicated that the Woods Inlet watershed likely contained a 

source, or sources, of PCBs. In 2003, a second USGS study to 

further characterize elevated PCB concentrations in sediment 

in Woods Inlet mapped the distribution of elevated PCB concentrations in Woods Inlet and identified possible source areas 

of PCBs in the watershed of Woods Inlet (Besse and others, 

2005). The findings of that report indicated that the highest PCB concentrations were near the mouth of Meandering 

Road Creek and that PCBs originate in the Meandering Road 

Creek watershed. Furthermore, total PCB concentrations in 

suspended and streambed sediment indicated storm drain outfall 4, which receives runoff from AFP4, was a likely source 

of PCBs to Meandering Road Creek and ultimately Woods 

Inlet. However, the study did not determine whether outfall 4 

was the only source of PCBs to Meandering Road Creek and 

Woods Inlet. Results from these studies (Harwell and others, 

2003; Besse and others, 2005) prompted a third study by the 

USGS. During 2004–07, the USGS investigated the degree of 

PCB contamination of Meandering Road Creek and Woods 

Inlet and attempted to identify possible sources of PCBs to 
6 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

Table 1. Concentrations of polychlorinated biphenyls in suspended-sediment samples collected from outfalls 4 and 5, Air Force Plant 4, 

Fort Worth, Texas, 2008.

[In micrograms per kilogram except as noted; PCB, polychlorinated biphenyl (increasing congener number generally indicates increasing chlorination of 

biphenyl structure); OF4, outfall 4; <, nondetection less than minimum reporting level; E, estimated (quantitatively identified at less than minimum reporting 

level); OF5, outfall 5; - -, not available; SPCBc, sum of 18 PCB congeners]

U.S. Geological 

Survey station 

number

Site 

identifier 

(fig. 2)

Sample date

Set 

number

PCB 

49

PCB 

52

PCB 

70

PCB 

101

PCB 

110

PCB 

118

PCB 

138

PCB 

146

PCB 

149

08045359 OF4 3/2/2008 002 <1.0 <1.0 <1.0 <1.0 3.8 1.6 3.7 0.54 3.0

08045359 OF4 11/10/2008 116 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 1.1 .62 3.2

08045359 OF4 duplicate 11/10/2008 116 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 .90 .38 2.8

324638097270901 OF5A 3/2/2008 002 <1.0 <1.0 <1.0 <1.0 E.67 .48 1.4 .23 1.7

324638097270901 OF5A 11/10/2008 116 <1.0 <1.0 <1.0 <1.0 <1.0 .65 1.2 .25 4.1

Sediment-quality guidelines:

Threshold effect concentration (TEC)1 - - - - - - - - - - - - - - - - - - - -

Minimum reporting level (MRL) - - 1.0 1.0 1.0 1.0 1.0 .1 .1 .1 1.0

Quality assurance samples:

Set blank 002 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 <.1 <.1 <1.0

Set spike, in percent recovery 002 53.2 92.5 95.5 97.2 101 115 100 114 76.8

Set blank 116 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 <.1 <.1 <1.0

Set spike, in percent recovery 116 45.8 42.4 49.3 56.1 58.9 73.4 98.4 79.5 50.5

Site identifier 

(fig. 2)

Sample 

date

PCB 

151

PCB 

170

PCB 

174

PCB 

177

PCB 

180

PCB 

183

PCB 

187

PCB 

194

PCB 

206 ∑PCBc

OF4 0.50 2.3 1.7 0.85 4.4 0.88 1.5 1.9 1.2 E28

OF4 11/10/2008 .69 3.3 2.1 1.5 5.3 1.1 1.8 1.5 .94 E23

OF4 duplicate 11/10/2008 .37 2.5 1.4 1.1 3.9 .79 1.4 1.2 1.4 E18

OF5A 3/2/2008 .44 2.1 2.3 1.3 3.9 .90 2.0 2.5 1.2 E21

OF5A 11/10/2008 .31 2.2 1.5 .92 3.6 .69 1.5 1.3 .84 E19

Sediment-quality guidelines:

Threshold effect concentration (TEC)1 - - - - - - - - - - - - - - - - - - 59.8

Minimum reporting level (MRL) .1 .1 .1 .1 .1 .1 .1 .1 .1 - -

Quality assurance samples:

Set blank <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 - -

Set spike, in percent recovery 108 94.2 96.9 94.3 96.8 98.2 109 101 100 - -

Set blank <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 - -

Set spike, in percent recovery 72.1 184 80.0 81.7 82.2 82.2 82.5 86.9 90.1 - -

1

 MacDonald and others (2000). 
Approach 7

Meandering Road Creek and Woods Inlet on the basis of 

suspended, streambed, and lake-bottom sediment samples collected in 2004 and 2006–07. Braun and others (2008) documented the extent of PCB contamination in Meandering Road 

Creek and Woods Inlet and identified runoff from outfalls 4 

and 5 at AFP4 as prominent sources of PCBs in Meandering 

Road Creek and Woods Inlet. Concentrations of selected PCB 

congeners analyzed during 2003–07 for the previous USGS 

studies are listed in appendix 1.

Engineering Controls Used to Alleviate 

Polychlorinated Biphenyl Contamination at 

Air Force Plant 4

Lockheed Martin Corporation selected two companies 

to implement engineering controls to potentially alleviate 

PCB contamination in the drainage areas of outfalls 4 and 

5 at AFP4. During late 2007 and early 2008 (about November 2007–February 2008), the companies used two types of 

engineering controls to clean up and contain PCBs in outfalls 

4 and 5 storm-drainage areas (fig. 2).

The first engineering control was done by Freese and 

Nichols, Inc., and involved a one-time sweeping of pavement 

within the drainage areas of outfalls 4 and 5 (fig. 2) to reduce 

potential PCB migration. Pavement sweeping occurred before 

6 a.m. or after 6 p.m., when it was likely few cars or employees would be present. Large, open paved areas were swept 

using standard, large-capacity pavement-sweeping equipment, 

whereas smaller paved areas were swept with compact sweeping equipment. Railroad tracks located within the drainage to 

outfall 4 were swept thoroughly to remove all debris around 

the rails and in depressions adjacent to rails. The area east 

of the electrical substation (fig. 2) within the concrete barriers in the outfall 4 drainage area also was swept. All debris 

was collected and stored in an on-site storage facility. The 

large-capacity pavement sweepers consist of a high-velocity 

air blower and vacuum with rotating circular brush heads; 

this type of equipment ensures that virtually all debris is collected in the hopper and little or no dust is generated. Smaller 

sweeper/vacuum vehicles of a similar type were used in areas 

too confined for the large-capacity sweepers. No water spray 

or mist-producing equipment was used in the sweeping process (Scott Harrison, Lockheed-Martin Corporation, written 

commun., 2009). 

The second engineering control was done by Burns 

and McDonnell Engineering Company, Inc. About 560 

square meters of the main electrical substation of AFP4 were 

regraded and covered with an asphaltic concrete cap (asphalt) 

(fig. 2). The top 8 centimeters (approximately) of gravel 

were removed from selected areas of the electrical substation; the soil subgrade was not excavated. Once the overlying 

gravel was stripped and stockpiled, any remaining gravel was 

compacted; then the previously stripped gravel was used as 

fill and compacted to bring the areas to 8 centimeters below 

the final grade. Dust control measures were used to minimize 

dust production. Because the excavated gravel was potentially 

contaminated with PCBs, the remaining stockpile of gravel 

was safely disposed of at an off-site location. Areas within the 

electrical substation, where potentially contaminated gravel 

was removed and the remaining gravel was compacted, were 

sprayed with a primer coat of liquid asphalt prior to installing the asphalt cap (fig. 2). The minimum design thickness of 

the asphalt cap was 8 centimeters, but in some instances the 

thickness was increased to match the grade of the concrete 

curb bordering the cap. The cap was sloped to induce drainage toward the outside perimeter (Scott Harrison, LockheedMartin Corporation, written commun., 2009).

Approach

Collection and Processing of SuspendedSediment Samples

Two suspended-sediment samples each were collected 

at outfall 4 (OF4, fig. 2) and outfall 5 (OF5A, fig. 2) in 2008 

for a total of four environmental samples. Suspended-sediment 

samples were collected by filling one 25-liter Nalgene carboy 

with runoff from the “first flush” (initial increase in flow) 

at each of the sample collection sites during a storm. Additional carboys were filled during some storms when the 

suspended-sediment concentration was too small (on the 

basis of visual inspection and professional judgment) to 

provide a sufficient sediment mass for chemical analyses. 

The limited scope of this project did not include measuring 

the discharge of Meandering Road Creek or precipitation 

associated with each storm, which could limit the comparability of samples collected during different storms. The 25-liter 

carboys were transported to the USGS Texas Water Science 

Center, North Texas Program Office in Fort Worth and stored 

on ice until filtering. Filtering each sample took several hours, 

so processing all samples from a storm typically took 1 to 

2 days.

Suspended sediment was isolated from the stormwater 

samples by in-line filtration following the methods of Mahler 

and Van Metre (2003). Braun and others (2008) provides a 

detailed description of how the suspended-sediment samples 

were collected. One of the samples collected previously (October 10, 2006) at outfall 5 was collected at site OF5B (fig. 2). 

The small distance between sampling sites OF5A and OF5B 

should not affect the comparison because there is no additional 

source of runoff between the two sites.

Analytical Methods

The USGS NWQL analyzed the suspended-sediment 

samples for 60 halogenated compounds including PCBs, 

antibacterial and antifungal compounds, organochlorine 
8 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

pesticides, organofluorine pesticides, and polybrominated 

diphenyl ethers (PBDEs) and other flame retardants using a 

custom analytical method. Custom methods have not been 

completely evaluated with the USGS guidelines for developing official methods. Since the publication of Braun and 

others (2008), the NWQL revised the analytical method 

for measuring halogenated compounds, including PCBs, in 

sediments, which resulted in the following PCB congeners 

not being quantified for this report: 8, 18, 22, 26, 28, 31, 33, 

44, and 95. The 18 PCB congeners analyzed in the samples 

collected during 2008 are listed in table 1. Although only the 

PCB congeners that were analyzed are discussed in this report, 

concentrations of all other compounds that were analyzed in 

the suspended-sediment samples from outfalls 4 and 5 are 

listed in appendix 2. The samples were extracted using an 

accelerated solvent extraction system (ASE) (Dionex Corporation, 2009) at a pressure of 13,800 kilopascals with a 50:50 

(volume per volume) mixture of water and isopropyl alcohol at 

120 degrees Celsius (°C) for 40 minutes and a 20:80 mixture 

of water and isopropyl alcohol at 200 °C for an additional 40 

minutes. The compounds of interest were isolated from the 

ASE extract using disposable solid-phase extraction (SPE) 

cartridges containing chemically modified N-vinylpyrrolidone 

divinylbenzene resin in addition to amino-propyl-based 

resin. The SPE cartridge was dried with nitrogen gas and the 

extracted compounds eluted with a 4:1 mixture of dichloromethane and diethyl ether. The extract was concentrated under 

a stream of nitrogen gas, cleaned on 2 grams of Florosil eluted 

with a 94:6 mixture of pentane and acetone, concentrated 

again under a stream of nitrogen gas, and then exchanged into 

hexane. The extracts were analyzed on an Agilent Technologies Model 5975 capillary-column gas chromatograph/mass 

spectrometer (GC/MS) using a 35-percent phenyl methylpolysiloxane capillary-column (Agilent Technologies, 2009) with 

the MS operated in the electron capture negative ion (ECNI) 

mode using ammonia as the reactant gas. The halogenated 

compounds were identified by selected ion monitoring (SIM) 

using the ions of interest (Mark Burkhardt and Steven Zaugg, 

U.S. Geological Survey, National Water Quality Laboratory, 

written commun., 2008). The analytical results and minimum 

reporting levels (MRLs) are listed in table 1. Compound concentrations quantitatively identified at less than the MRL were 

reported as estimated (E).

Quality Control

For the four environmental samples collected during this 

study, the quality control for PCB analyses consisted of one 

duplicate sample, one laboratory blank sample, and spike and 

surrogate compound recovery rates for two sets of environmental samples. The recovery of surrogate compounds is monitored by the laboratory with every set of 12 environmental 

samples (Mark Burkhardt and Steven Zaugg, U.S. Geological 

Survey, National Water Quality Laboratory, written commun., 

2008). The samples collected for this study were analyzed as 

part of different sets of environmental samples, sets 002 and 

116. All PCB congener concentrations in the blank sample 

were quantified at values less than the applicable PCB congener MRL of either 0.1 or 1.0 microgram per kilogram (μg/kg) 

(table 1). The average spike recoveries were 97 and 78 percent 

for sets 002 and 116, respectively. One sample from this study 

(OF4, November 10, 2008) was selected for duplicate analysis in set 116; however the duplicate for set 002 was not a 

sample from this study and is not included in this report. In the 

OF4 duplicate sample, the average relative percent difference 

(RPD) for compounds with concentrations greater than the 

respective MRLs was 33 percent. RPD was computed using 

the equation

RPD = |C1 – C2|/((C1 + C2)/2) x 100, (1)

where 

C1 = concentration from environmental sample; and

C2 = concentration from duplicate sample.

Selected PCB congeners and chlorinated pesticides were 

added as surrogates prior to extraction to monitor the extraction process. The average surrogate recoveries for set 002 were 

71, 47, and 47 percent for 4,4-dibromooctafluorobiphenyl 

(C12Br2F8), 2,2',3,3',5,5',6,6'-octachlorobiphenyl (PCB 202- 13C12), and 1,1'-Bis(p-chlorophenyl)-2,2,2-trichloroethane 

(DDT-d8), respectively. The average surrogate recoveries for 

set 116 were 40, 59, and 76 percent for C12Br2F8, PCB 202- 13C12, and DDT-d8

, respectively. All surrogate recoveries are 

listed in appendix 2. Because a new, custom analytical method 

was used, acceptable ranges for spike and surrogate recoveries 

had not been established, and no past results using the same 

analytical method were available for comparison.

Polychlorinated Biphenyls in 

Suspended-Sediment Samples from 

Outfalls to Meandering Road Creek

Because of the small number of samples collected, it 

was not possible to statistically test if concentrations of PCB 

congeners obtained in this study were statistically different 

from concentrations of PCB congeners obtained during previous USGS studies. Eight suspended-sediment samples were 

collected at outfall 4 and three suspended-sediment samples 

(and one duplicate) at outfall 5 in previous studies, before the 

implementation of engineering controls (sweeping and capping) at AFP4. For comparison, results for the same 18 PCB 

congeners that were analyzed in suspended-sediment samples 

collected from outfalls 4 and 5 in the previous studies are 

listed in appendix 1. For this study, two suspended-sediment 

samples were collected at each of the outfalls in 2008, after the 

engineering controls had been implemented. 

At outfall 4, ∑PCBc

 before implementation of engineering controls ranged from E18 to E310 μg/kg (appendix 1) and 

after implementation ∑PCBc was E23 and E28 μg/kg (table 1). 
Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek 9

At outfall 5, ∑PCBc before implementation of engineering 

controls ranged from E29 to E330 μg/kg (appendix 1) and 

after implementation ∑PCBc was E19 and E21 μg/kg (table 1). 

The ∑PCBc at both outfalls before the engineering controls 

was higher than the ∑PCBc after the engineering controls.

Analyses of the results are limited to comparison to 

TEC benchmark values (sediment-quality guidelines) and 

graphical analysis of normalized concentrations of the selected 

congeners because of the small dataset. To compare PCB 

congener concentrations to the TEC, ratios of ∑PCBc to the 

TEC were determined (fig. 3). For each sample, ∑PCBc was 

compared to the TEC of 59.8 μg/kg for total PCBs established 

by MacDonald and others (2000); in samples with ratios 

greater than 1, ∑PCBc exceeds the TEC. ∑PCBc exceeded the 

TEC for 75 percent of the samples collected at outfall 4 and 

67 percent of the samples collected at outfall 5 before the 

implementation of engineering controls. ∑PCBc did not exceed 

the TEC in samples collected at either outfall 4 or outfall 5 

(two at each outfall) after the implementation of engineering 

controls.

Of the 18 PCB congeners that were quantified, 10 congeners were selected for graphical analysis on the basis of their 

detection frequency, range of chlorination, concentrations, and 

concentration variation between sampling sites. To normalize PCB concentrations, ratios of individual concentrations of 

PCB congeners to the sum of the 10 selected PCB congeners 

were determined, hereinafter referred to as congener ratios. 

The relative prominence of the 10 selected PCB congeners 

was evaluated by graphical analysis of congener ratios (fig. 4).

Before the implementation of engineering controls, 

congeners 110, 138, and 180 were most prominent on the 

basis of normalized concentrations of PCB congeners in the 

suspended-sediment samples at outfall 4 (fig. 4); this conclusion, as well as subsequent conclusions in this paragraph, 

are based solely on visual observations of figure 4. After the 

implementation of engineering controls, an overall decrease 

1

 Threshold effect concentration (MacDonald and others, 2000).

2

 Engineering controls (asphalt caps and sweeping) implemented late 2007 and early 2008, about November 2007–February 2008, 

 to potentially alleviate PCB contamination in drainage areas of outfalls 4 and 5.

ΣPCBc ΣPCB = TEC c = TEC

0

1

2

3

4

5

6

RATIO OF 

ΣPCBC , SUSPENDED SEDIMENT, TO TEC1

0

1

2

3

4

5

6

RATIO OF 

ΣPCBC , SUSPENDED SEDIMENT, TO TEC1

Before

 engineering

 controls2

 After

 engineering

 controls2

Before

 engineering

 controls2

 After

 engineering

 controls2

OF4 10/22/2004

OF4 11/16/2004

OF4 12/6/2004

OF4 8/27/2006

OF4 10/10/2006

OF4 3/2/2008

OF4 11/10/2008

EXPLANATION

Site identifier and

sampling date (before

implementation of

engineering controls)

OF4 9/11/2003

OF4 10/5/2003

OF4 8/30/2003

Site identifier and

sampling date (after

implementation of

engineering controls)

OF5A 10/22/2004

OF5B 10/10/2006

OF5A 3/2/2008

OF5A 11/10/2008

OF5A 5/24/2007

Site identifier and

sampling date (before

implementation of

engineering controls)

Site identifier and

sampling date (after

implementation of

engineering controls)

EXPLANATION

OUTFALL 4 OUTFALL 5

Figure 3. Ratios of total polychlorinated biphenyl (PCB) concentrations (sum of 18 reported congeners [∑PCBc]) to threshold effect 

concentration, a consensus-based sediment-quality guideline for PCBs, for suspended-sediment samples collected from outfalls 4 and 

5, Air Force Plant 4, Fort Worth, Texas, 2003–08. 
10 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek EXPLANATION RATIO OF INDIVIDUAL PCB CONGENER CONCENTRATION TO SUM OF 10 SELECTED PCB CONGENERS, SUSPENDED SEDIMENT Symbol and corresponding sampling date PCB CONGENER CONCENTRATION, SUSPENDED SEDIMENT, IN MICROGRAMS PER KILOGRAM Bar graph symbol and corresponding sampling date 8/30/2003 9/11/2003 10/5/2003 10/22/2004 11/16/2004 12/6/2004 8/27/2006 10/10/2006 5/24/2007

03/02/200811/10/2008

8/30/20039/11/200310/5/200310/22/200411/16/200412/6/20048/27/200610/10/20065/24/200703/02/200811/10/2008

PCB CONGENER NUMBER

52 101 110 118 138 149 151 170 180 187

PCB CONGENER NUMBER

52 101 110 118 138 149 151 170 180 187

0.400.350.300.250.200.150.100.05

0

0.400.350.300.250.200.150.100.05

0

RATIO OF INDIVIDUAL PCB CONGENER CONCENTRATION TO

SUM OF 10 SELECTED PCB CONGENERS, SUSPENDED SEDIMENT

0.400.350.300.250.200.150.100.05

0

0.400.350.300.250.200.150.100.05

0

RATIO OF INDIVIDUAL PCB CONGENER CONCENTRATION TO

SUM OF 10 SELECTED PCB CONGENERS, SUSPENDED SEDIMENT

100

9080706050403020100

100

9080706050403020100

PCB CONGENER CONCENTRATION, SUSPENDED SEDIMENT, IN MICROGRAMS PER KILOGRAM100 908070605040302010

01009080706050403020100

PCB CONGENER CONCENTRATION, SUSPENDED SEDIMENT, IN MICROGRAMS PER KILOGRAM

1 Engineering controls (asphalt caps and sweeping) implemented late 2007 and early 2008, about November 2007–February 2008, to potentially alleviate PCB contamination in drainage areas of outfalls 4 and 5.

( 1.0)

Outfall 5 (OF5A all sampling dates except OF5B 10/10/2006),2004–07 (before engineering controls1

)

Outfall 4 (OF4), 2003–06 (beforeengineering controls1

)

Outfall 4 (OF4), 2008 (after engineering controls1

) Outfall 5 (OF5A), 2008 (after engineering controls1

)

Figure 4. Ratio of individual polychlorinated biphenyl (PCB) congener concentrations to sum of 10 selected PCB congeners for suspended-sediment samples collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2003–08. 
Summary 11

in concentrations of PCB congeners was observed in addition 

to a decrease in the prominence of the congener 110 and 138 

ratios. An increase in the prominence of the congener 149 

ratio was also observed after the implementation of engineering controls. This shift in prominence from lighter, less chlorinated congeners (110 and 138) to a heavier, more chlorinated 

congener (149) might have resulted from the engineering 

controls implemented at AFP4 near the sample collection 

sites. Additionally, the heavier, more chlorinated congeners are 

more likely to sorb to solids, while less chlorinated congeners 

are more likely to volatilize (Eisenreich, Capel, and Looney, 

1983; Eisenreich and others, 1992; Pearson and others, 1996). 

The agitation associated with sweeping activities and gravel 

stripping might have induced volatilization that would have 

favored removal of the lighter congeners. The shift in congener ratios might also have resulted from the transition in analytical methods, or it could be the result of the small number 

of samples available for comparison.

Before the implementation of engineering controls, the 

suspended-sediment PCB concentrations at outfall 5 (fig. 4) 

exhibited a congener ratio pattern dominated by congener 

138 and the more highly chlorinated PCB congeners (170, 

180, and 187). PCB congeners 110 and 118, which were more 

prevalent at outfall 4, were either not detected at outfall 5 or 

detected at much lower concentrations, resulting in smaller 

congener ratios for outfall 5. After the implementation of 

engineering controls, a decrease in concentrations of PCB congeners was observed in addition to a decrease in prominence 

of congeners 138 and 180. An increase in the prominence of 

congener 149 also occurred. The same possible explanations 

given for the shift in congener ratios at outfall 4 apply to the 

shift in congener ratios at outfall 5.

Summary

Meandering Road Creek is an intermittent stream and 

tributary to Lake Worth, a reservoir on the West Fork Trinity River on the western edge of Fort Worth, Texas. U.S. Air 

Force Plant 4 (AFP4) is on the eastern shore of Woods Inlet, 

an arm of Lake Worth that extends south from the main body 

of the lake. Meandering Road Creek gains inflow from several 

stormwater outfalls as it flows across AFP4 to its terminus at 

Woods Inlet. Lake Worth and Meandering Road Creek have 

been the subject of several studies to characterize concentrations of polychlorinated biphenyls (PCBs) (and other contaminants) in the water and sediments of these water bodies; the 

sources of the PCBs are believed to originate primarily from 

AFP4. Two previous U.S. Geological Survey (USGS) reports 

documented elevated PCB concentrations in surficial sediment 

samples collected in Woods Inlet relative to those in surficial 

sediment samples collected in other parts of Lake Worth; the 

first report using samples collected during 2000–2001, the 

second using samples collected in 2003. The second report 

also identified some of the sources of PCBs to Lake Worth. 

These reports were followed by a third USGS report that 

documented the extent of PCB contamination in Meandering 

Road Creek and Woods Inlet on the basis of samples collected 

during 2004 and 2006–07 and identified runoff from outfalls 

4 and 5 at AFP4 as prominent sources of PCBs to Meandering 

Road Creek and Woods Inlet. 

This report describes the results of a fourth study by 

the USGS, in cooperation with the Lockheed Martin Corporation, to investigate the concentration of PCBs in suspendedsediment samples in storm runoff from outfalls 4 and 5 at 

AFP4 following the implementation of engineering controls 

designed to potentially alleviate PCB contamination in the 

drainage areas of these outfalls. The first engineering control 

consisted of a one-time sweeping of pavement within the 

drainage areas of outfalls 4 and 5 to reduce potential PCB 

migration. The second engineering control involved regrading 

and installing an asphalt cap over about 560 square meters of 

the main electrical substation of AFP4. The USGS collected 

suspended-sediment samples from outfalls 4 and 5 during 

storms on March 2 and November 10, 2008, and analyzed the 

samples for selected PCBs. The sums of concentrations of 

18 reported PCB congeners (∑PCBc

) in suspended-sediment 

samples collected during 2003–07 (before implementation 

of engineering controls) for the previous USGS studies are 

compared to ∑PCBc in suspended-sediment samples collected 

during 2008 (after implementation of engineering controls). 

Because of the small number of samples collected and lack of 

runoff and precipitation data to evaluate comparability of sampling conditions before and after implementation of engineering controls, all conclusions are preliminary.

∑PCBc in suspended-sediment samples before implementation of engineering controls ranged from estimated (E)18 

to E310 micrograms per kilogram (μg/kg) and E29 to E330 

μg/kg for outfalls 4 and 5, respectively. ∑PCBc after implementation was E23 and E28 μg/kg and E19 and E21 μg/kg 

for outfalls 4 and 5, respectively. The ∑PCBc at both outfalls 

before the engineering controls was higher than the ∑PCBc

after the engineering controls.

The ∑PCBc in suspended-sediment samples collected at 

AFP4 before and after implementation of engineering controls 

also is compared to the threshold effect concentration (TEC), 

the concentration below which adverse effects to benthic biota 

rarely occur. ∑PCBc exceeded the TEC for 75 percent of the 

samples collected at outfall 4 and 67 percent of the samples 

collected at outfall 5 before the implementation of engineering 

controls. ∑PCBc

 did not exceed the TEC in samples collected 

at either outfall 4 or outfall 5 after the implementation of engineering controls.

The relative prominence of 10 selected PCB congeners 

was evaluated by graphical analysis of ratios of individual 

concentrations of the 10 PCB congeners to the sum of these 

PCB congeners. Before the implementation of engineering 

controls, PCB congeners 110, 138, and 180 were most prominent on the basis of normalized concentrations of PCB congeners in the suspended-sediment samples at outfall 4 (on the 

basis of visual observations of the graphical data). After the 
12 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

implementation of engineering controls, an overall decrease 

in concentrations of PCB congeners was observed in addition 

to a decrease in the prominence of congeners 110 and 138 

and an increase in the prominence of congener 149. This shift 

in prominence from lighter, less chlorinated congeners (110 

and 138) to a heavier, more chlorinated congener (149) might 

have resulted from the engineering controls implemented at 

AF4. Before the implementation of engineering controls, the 

suspended-sediment PCB concentrations at outfall 5 exhibited 

a congener ratio pattern dominated by congener 138 and the 

more highly chlorinated PCB congeners (170, 180, and 187). 

After the implementation of engineering controls, a decrease 

in concentrations of PCB congeners was observed in addition 

to a decrease in the prominence of congeners 138 and 180 and 

an increase in the prominence of congener 149. The shift in 

congener ratios at outfall 5 also might have resulted from the 

engineering controls.

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Appendixes 1–2
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Appendix 1 17

Appendix 1. Concentrations of selected polychlorinated biphenyl congeners in suspended-sediment samples collected from outfalls 4 

and 5, Air Force Plant 4, Fort Worth, Texas, 2003–07. 

[In micrograms per kilogram except as noted; PCB, polychlorinated biphenyl; OF4, outfall 4; E, estimated (quantitatively identified at less than minimum reporting level); <, nondetection less than minimum reporting level; OF5, outfall 5; dup, duplicate; - -, not available; SPCBc

, sum of 18 PCB congeners]

U.S. Geological 

Survey station 

number

Site 

identifier 

(fig. 2)

Sample 

date

PCB 

49

PCB 

52

PCB 

70

PCB 

101

PCB 

110

PCB 

118

PCB 

138

PCB 

146

PCB 

149

PCB 

151

08045359 OF4 08/30/2003 E0.75 E1.6 E2.6 E5.1 9.7 E8.0 17 E2.4 E8.4 E3.5

08045359 OF4 09/11/2003 E.60 E1.8 E2.3 E4.5 E8.3 E6.4 E13 E2.1 E7.1 E1.5

08045359 OF4 10/05/2003 <11 E6.6 <11 14 18 E4.4 28 E3.4 14 E4.4

08045359 OF4 10/22/2004 <1.0 <1.0 <1.0 E.8 1.9 1.0 3.6 <1.0 1.0 <1.0

08045359 OF4 11/16/2004 <19 <19 <19 E12 E19 E19 E40 <19 E19 <19

08045359 OF4 12/06/2004 <14 E8.2 E10 E26 E37 E32 E53 <14 E26 <14

08045359 OF4 08/27/2006 <36 <36 <36 <36 E4.5 E3.4 E9.4 <36 E2.9 <36

08045359 OF4 10/10/2006 <10 E3.0 E6.8 E8.7 20 14 33 E3.9 15 E3.3

324638097270901 OF5A 10/22/2004 <45 <45 <45 <45 <45 <45 <45 <45 <45 <45

324638097270901 OF5B1 10/10/2006 <140 <140 <140 <140 <140 <140 E43 <140 <140 <140

324638097270901 OF5A 05/24/2007 <2.0 <2.0 <2.0 E1.2 2.2 2.1 8.2 <2.0 5.5 2.1

324638097270901 OF5A dup 05/24/2007 <2.0 <2.0 <2.0 E1.4 2.5 2.4 8.7 <2.0 5.7 2.2

Sediment-quality guidelines:

Threshold effect concentration (TEC)2 - - - - - - - - - - - - - - - - - - - -

Site 

identifier 

(fig. 2)

Sample 

date

PCB 

170

PCB 

174

PCB 

177

PCB 

180

PCB 

183

PCB 

187

PCB 

194

PCB 

206 SPCBc

Surrogates, in percent recovery 

(acceptable range)

Isodrin alphaHCH-d6

Nonachlorobiphenyl

OF4 08/30/2003 E5.4 E4.5 E2.4 9.9 E3.4 E5.3 E2.8 <0.16 E93 - - - - - -

OF4 09/11/2003 E4.2 E3.2 E2.0 E8.8 E2.2 E4.4 E2.1 <1.0 E75 - - - - - -

OF4 10/05/2003 12 E10 E5.4 24 E5.0 13 E3.4 <11 E170 - - - - - -

OF4 10/22/2004 2.0 1.0 E.6 2.9 <1.0 1.6 1.0 <1.0 E18 69 (42–94) 79 (21–140) 170 (19–125)

OF4 11/16/2004 E24 E13 <19 E41 <19 E20 E14 <19 E220 57 (42–94) 77 (21–140) 120 (19–125)

OF4 12/06/2004 E20 E11 E8.8 E33 <14 E16 E9.7 <14 E310 61 (42–94) 85 (21–140) 110 (19–125)

OF4 08/27/2006 <36 <36 <36 E4.8 <36 <36 <36 <36 E25 72 (41–121) 83 (58–124) 76 (14–142)

OF4 10/10/2006 E7.5 E5.3 E3.5 15 <10 E7.6 E3.7 E2.9 E160 76 (41–121) 75 (58–124) 81 (14–142)

OF5A 10/22/2004 <45 <45 <45 E29 <45 <45 <45 <45 E29 76 (42–94) 83 (21–140) 140 (19–125)

OF5B1 10/10/2006 E49 E31 <140 E94 <140 E33 E51 E27 E330 87 (41–121) 82 (58–124) 88 (14–142)

OF5A 05/24/2007 9.0 8.4 5.9 23 4.1 8.4 7.9 4.2 E93 50 (41–121) 66 (58–124) 92 (14–142)

OF5A 

dup

05/24/2007 9.3 8.7 6.1 21 4.3 8.7 7.9 4.2 E94 50 (41–121) 62 (58–124) 90 (14–142)

Sediment-quality 

guidelines:

Threshold effect concentration (TEC)2

- - - - - - - - - - - - - - - - 59.8 - - - - - -

1

 Sample required custom preparation (air dried) at laboratory because normal centrifugation could not separate solids from water.

2

 MacDonald and others (2000).

Appendix 1
18 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

Appendix 2. Concentrations of antibacterial, antifungal, pesticide, and flame retardant compounds in suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2008.

[In micrograms per kilogram except as noted; OF4, outfall 4; <, nondetection less than minimum reporting level; E, estimated (quantitatively identified at less 

than minimum reporting level; dup, duplicate; OF5, outfall 5; - -, not available; S, sum; SPCBc, sum of 18 PCB congeners (table 1); C12Br2F8, 4,4-dibromooctafluorobiphenyl; PCB 202-13C12, 2,2'3,3'5,5'6,6'-octachlorobiphenyl; DDT-d8

, 1,1'-Bis(p-chlorophenyl)-2,2,2-trichloroethane]

U.S. Geological 

Survey station 

number

Site 

identifier 

(fig. 2)

Sample date Set 

number

Octachlorostyrene

Antibacterial/

antifungal Pesticides

MethoxytriclosanTriclosan

Benfluralin 

(benefin)

Chloridazon 

(PCA)

Chlorpyrifos

cisChlordane

08045359 OF4 3/2/2008 002 <1.0 <1.0 17 E0.15 0.16 3.5 1.1

08045359 OF4 11/10/2008 116 <1.0 <1.0 9.2 E.015 <.1 <.1 1.3

08045359 OF4 dup 11/10/2008 116 <1.0 <1.0 9.0 E.015 <.1 <.1 .93

324638097270901 OF5A 3/2/2008 002 <1.0 <1.0 <5.0 <.1 <.1 1.2 .33

324638097270901 OF5A 11/10/2008 116 <1.0 <1.0 27 <.1 <.1 <.1 .46

Sediment quality guidelines:

Threshold effect concentration (TEC)1 - - - - - - - - - - - - - - - -

Minimum reporting level (MRL) - - 1.0 1.0 5.0 .1 .1 .1 .1

Quality assurance samples:

Set blank 002 <1.0 <1.0 E.43 <.1 E.085 <.1 <.1

Set spike, in percent recovery 002 86.6 152 94 36.9 158 86.3 87.5

Set blank 116 <1.0 <1.0 1.31 <.1 <.1 <.1 <.1

Set spike, in percent recovery 116 77.4 92.7 102 52.6 98.9 73.2 89.7

Site 

identifier 

(fig. 2)

Sample 

date

Pesticides

cisNonachlor

CyfluthrinCyhalothrin

DCPA 

(Dacthal)

Desulfinyl 

fipronil

Dieldrin Endosulfan I

FipronilFipronil 

sulfide

Hexachlorobenzene 

(HCB)

Oxychlordane

OF4 3/2/2008 0.33 E11 E2.2 1.2 E0.08 0.85 0.56 1.3 E0.02 0.29 <1.0

OF4 11/10/2008 .38 3.6 8.2 .41 .28 1.5 .24 <.1 E.034 <.1 <1.0

OF4 dup 11/10/2008 .27 2.8 6.7 .31 .18 1.1 .15 <.1 E.034 <.1 <1.0

OF5A 3/2/2008 E.07 E2.9 E.25 .32 E.03 .12 .15 .28 E.01 <.1 <1.0

OF5A 11/10/2008 E.10 2.6 4.9 .38 .11 .41 E.09 1.5 E.025 <.1 <1.0

Sediment quality guidelines:

Threshold effect concentration (TEC)1 - - - - - - - - - - 1.90 - - - - - - - - - -

Minimum reporting level (MRL) .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 1.0

Quality assurance samples:

Set blank <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 E.079 <1.0

Set spike, in percent recovery 87.3 56.5 43.4 114 70.5 105 80.4 66.0 19.8 150 78.4

Set blank <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 <.1 E.091 <1.0

Set spike, in percent recovery 80.1 112 86.4 82.4 62.4 77.6 69.0 73.0 74.4 75.0 93.8

Appendix 2
Appendix 2 19

Appendix 2. Concentrations of antibacterial, antifungal, pesticide, and flame retardant compounds in suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2008—Continued.

Site 

identifier

(fig. 2)

Sample 

date

Pesticides

Oxyfluorfen

Pendimethlin

Pentachloronitrobenzene

p,p’-

DDD

p,p’-

DDE

p,p’-

DDT

TefluthrinTetradifon

transChlordanetransNonachlor

Trifluralin

OF4 3/2/2008 <5.0 E1.0 <1.0 <1.0 E0.88 <1.0 <0.1 <0.1 0.88 0.68 E0.25

OF4 11/10/2008 <5.0 <1.0 <1.0 <1.0 E.81 <1.0 <.1 <.1 .95 .61 E.024

OF4 dup 11/10/2008 <5.0 <1.0 <1.0 <1.0 E.62 <1.0 <.1 <.1 .71 .42 E.016

OF5A 3/2/2008 <5.0 <1.0 <1.0 <1.0 E.41 <1.0 <.1 <.1 .23 .16 <.10

OF5A 11/10/2008 <5.0 <1.0 <1.0 <1.0 3.7 <1.0 <.1 <.1 .38 .21 <.10

Sediment quality guidelines:

Threshold effect concentration 

(TEC)1

- - - - - - 4.88 3.16 4.16 - - - - - - - - - -

Minimum reporting level (MRL) 5.0 1.0 1.0 1.0 1.0 1.0 .1 .1 .1 .1 .1

Quality assurance samples:

Set blank <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 <.1 <.1 <.1 <.1

Set spike, in percent recovery 116 67.0 114 97.6 134 110 51.8 54.5 82.7 76.7 38.3

Set blank <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <.1 <.1 <.1 <.1 <.1

Set spike, in percent recovery 79.5 74.3 93.3 74.6 103 100 77.2 80.6 82.9 83.6 49.9

Site

identifier 

(fig. 2)

Sample 

date

Polybrominated diphenyl ethers (PBDEs) and other flame retardants

PBDE 

47

PBDE 

66

PBDE 

71

PBDE 

85

PBDE 

99

PBDE 

100

PBDE 

138

OF4 3/2/2008 13 0.59 <0.1 0.92 14 4.5 0.49

OF4 11/10/2008 6.4 .31 <.1 .62 9.5 2.4 .66

OF4 dup 11/10/2008 3.8 .23 <.1 .41 4.7 1.3 .87

OF5A 3/2/2008 3.5 .20 <.1 .28 4.3 1.3 .37

OF5A 11/10/2008 2.5 <.1 <.1 .34 3.6 .95 .35

Sediment quality guidelines:

Threshold effect concentration 

(TEC)1

- - - - - - - - - - - - - -

Minimum reporting level (MRL) .1 .1 .1 .1 .1 .1 .1

Quality assurance samples:

Set blank .344 <.1 <.1 <.1 E.098 <.1 <.1

Set spike, in percent recovery 256 60 106 117 130 109 112

Set blank .342 <.1 <.1 <.1 E.078 E.031 <.1

Set spike, in percent recovery 136 46.7 83.0 84.4 84.0 83.5 79.8
20 Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek

Appendix 2. Concentrations of antibacterial, antifungal, pesticide, and flame retardant compounds in suspended-sediment samples 

collected from outfalls 4 and 5, Air Force Plant 4, Fort Worth, Texas, 2008—Continued.

Site

identifier 

(fig. 2)

Sample 

date

Polybrominated diphenyl ethers (PBDEs) and other flame retardants

PBDE 

153

PBDE 

154

PBDE 

183

Declorane 

plus

Firemaster 680 

[1,2-bis(2,4,6-Tribromophenoxy) ethane]

Pentabromotoluene

OF4 3/2/2008 3.0 2.0 1.2 4.5 1.7 <1.0

OF4 11/10/2008 2.3 1.2 1.4 6.9 5.8 <1.0

OF4 dup, 11/10/2008 2.1 .93 1.5 4.3 4.5 <1.0

OF5A 3/2/2008 1.8 .79 .88 4.0 .49 <1.0

OF5A 11/10/2008 .94 .66 1.4 19 3.3 <1.0

Sediment quality guidelines:

Threshold effect concentration (TEC)1 - - - - - - - - - - - -

Minimum reporting level (MRL) .1 .1 .1 .1 .1 1.0

Quality assurance samples:

Set blank <.1 <.1 <.1 <.1 <.1 <1.0

Set spike, in percent recovery 106 101 85.3 102 91.7 112

Set blank <.1 <.1 <.1 <.1 <.1 <1.0

Set spike, in percent recovery 78.9 79.2 70.5 94.4 79.8 93.5

Site 

identifier 

(fig. 2)

Sample 

date

Calculated Surrogates, in percent recovery

SPesticides SDDTs SPCBc

SFlame 

retardants C12Br2

F8

PCB 202- 13C12

DDT-d8

OF4 3/2/2008 26 0.88 28 46 64.1 47.2 51.8

OF4 11/10/2008 17 .81 23 37 42.7 56.7 71.6

OF4 dup 11/10/2008 14 .63 18 25 40.6 63.1 80.2

OF5A 3/2/2008 6.0 .41 21 18 78.0 47.0 42.1

OF5A 11/10/2008 11 3.7 19 33 37.1 57.2 75.7

Sediment quality guidelines:

Threshold effect concentration (TEC)1 - - 5.28 59.8 - - - - - - - -

Minimum reporting level (MRL) - - - - - - - - - - - - - -

Quality assurance samples:

Set blank - - - - - - - - 34.8 46.1 48.4

Set spike, in percent recovery - - - - - - - - 72.0 92.4 91.4

Set blank - - - - - - - - 57.3 74.9 105

Set spike, in percent recovery - - - - - - - - 54.6 75.1 84.0

1

 MacDonald and others (2000). 

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Braun and Wilson—Polychlorinated Biphenyls in Suspended-Sediment Samples from Outfalls to Meandering Road Creek—SIR 2010–5076

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I SBN 978- 1- 4113- 2840- 2

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