U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2016–5039

Prepared in cooperation with the San Antonio River Authority

Occurrence and Concentrations of Selected Trace Elements 

and Halogenated Organic Compounds in Stream Sediments 

and Potential Sources of Polychlorinated Biphenyls, Leon 

Creek, San Antonio, Texas, 2012–14
Front cover, Looking upstream at U.S. Geological Survey station 08181435 Leon Creek at Loop 410 at San 

Antonio, Texas, October 2013.

Back cover, U.S. Geological Survey hydrologic technician Michael Scheider collecting a streambedsediment sample from U.S. Geological Survey station 292240098353600 Leon Creek at Lackland Air Force 

Base Golf Course, San Antonio, Texas, February 2013.
Occurrence and Concentrations of 

Selected Trace Elements and Halogenated 

Organic Compounds in Stream Sediments 

and Potential Sources of Polychlorinated 

Biphenyls, Leon Creek, San Antonio, Texas, 

2012–14

By Jennifer T. Wilson 

Prepared in cooperation with the San Antonio River Authority

Scientific Investigations Report 2016–5039

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia: 2016

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

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Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Wilson, J.T., 2016, Occurrence and concentrations of selected trace elements and halogenated organic compounds 

in stream sediments and potential sources of polychlorinated biphenyls, Leon Creek, San Antonio, Texas, 2012–14: 

U.S. Geological Survey Scientific Investigations Report 2016–5039, 99 p., http://dx.doi.org/10.3133/sir20165039.

ISSN 2328-031X (print)

ISSN 2328-0328 (online)
iii

Acknowledgments

The author wishes to acknowledge personnel at Joint Base San Antonio-Lackland for their 

assistance with base access to sample Leon Creek within the base boundaries. She also wishes 

to acknowledge the Texas Department of Transportation for their assistance with the installation 

of a passive sampler at the bridge over Leon Creek and Interstate Highway 410. 

v

Contents

Acknowledgments .......................................................................................................................................iii

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

Introduction ....................................................................................................................................................2

Purpose and Scope .............................................................................................................................2

Description of the Study Area and Sampling Sites ........................................................................6

Previous Studies ..................................................................................................................................7

Methods ..........................................................................................................................................................7

Sample Collection ................................................................................................................................8

Streambed-Sediment Samples .................................................................................................8

Suspended-Sediment Samples ................................................................................................9

Analytical Methods ..............................................................................................................................9

Quality Control ....................................................................................................................................11

Concentrations and Occurrence of Selected Trace Elements and Halogenated Organic 

Compounds .....................................................................................................................................17

Trace Elements ...................................................................................................................................17

Halogenated Organic Compounds ..................................................................................................19

Pesticides ...................................................................................................................................19

Flame Retardants ......................................................................................................................21

Polychlorinated Biphenyls ......................................................................................................22

Potential Sources of Polychlorinated Biphenyls ...................................................................................24

Summary .......................................................................................................................................................33

References Cited ........................................................................................................................................34

Figures

1. Maps showing locations of the A, Leon Creek drainage area and fish 

consumption advisory stream segment and B, stream-sediment sampling sites, 

in Bexar County, Texas ................................................................................................................3

2. Map showing locations of stream-sediment sampling sites on Leon Creek in San 

Antonio, Texas, 2007–9 and 2012–14 .........................................................................................5

3. Photographs showing streambed-sediment sample collection methods used 

at Leon Creek in San Antonio, Texas, 2012–14. A, Hydrologic technician collecting 

surficial streambed sediment from a depositional zone; and B, Hydrologic 

technician processing a surficial streambed-sediment sample .........................................8

4. Diagram and photographs showing suspended-sediment sample collection 

methods used at Leon Creek in San Antonio, Texas, 2012–14. A, Passive sampler 

used to collect suspended-sediment samples; B, Hydrologic technician removing 

bottles from passive samplers after a storm; and C, Suspended sediment 

isolated on a Teflon membrane after filtration of a stormwater-runoff sample ..............10

5. Graphs showing the comparison of consensus-based sediment-quality 

guidelines with concentrations of trace elements in streambed- and suspendedsediment samples collected from Leon Creek, San Antonio, Texas, 2012–14 .................18
vi

6. Graph showing the percentage of organic carbon in streambed- and suspendedsediment samples collected from Leon Creek, San Antonio, Texas, 2007–9 and 

2012–14 ........................................................................................................................................19

7. Graph showing detection frequencies of pesticides in streambed- and 

suspended-sediment samples, by site (table 1), collected from Leon Creek, San 

Antonio, Texas, 2012–14 ............................................................................................................20

8. Graphs showing the comparison of consensus-based sediment-quality

 guidelines with concentrations of pesticides in streambed- and suspendedsediment samples collected from Leon Creek, San Antonio, Texas, 2012–14 .................21

9. Graph showing detection frequencies of brominated flame retardants in 

streambed- and suspended-sediment samples, by site (table 1), collected from 

Leon Creek, San Antonio, Texas, 2012–14 .............................................................................22

10. Graphs showing the comparison of Environment Canada (2013) Federal 

Environmental Quality Guidelines with concentrations of brominated flame 

retardants in streambed- and suspended-sediment samples collected from Leon 

Creek, San Antonio, Texas, 2012–14 .......................................................................................23

11. Graph showing detection frequencies of polychlorinated biphenyl congeners in 

streambed- and suspended-sediment samples, by site (table 1), from Leon Creek, 

San Antonio, Texas, 2012–14 ....................................................................................................24

12. Graph showing concentrations of total polychlorinated biphenyls in streambedand suspended-sediment samples collected from Leon Creek, San Antonio, 

Texas, 2007–9 and 2012–14 .......................................................................................................25

13. Graphs showing examples of polychlorinated biphenyl congener concentrations 

normalized to the sum of the detected congener concentrations in selected 

stream-sediment samples collected from Leon Creek, San Antonio, Texas, 

2007–9 and 2012–14 ...................................................................................................................26

14. Graphs showing comparison of polychlorinated biphenyl congeners in 

commercial Aroclor mixtures and selected streambed- and suspended-sediment 

samples collected from Leon Creek, San Antonio, Texas, 2007–8 and 2014 ....................32

Tables

1. Characteristics of the catchment area of each site where streambed- and 

suspended-sediment samples were collected from Leon Creek, San Antonio, 

Texas, 2012–14 ..............................................................................................................................6

2. Streambed- and suspended-sediment samples collected from sites on Leon 

Creek, San Antonio, Texas, 2012–14 .........................................................................................8

3. Relative percent difference (RPD) of concentrations of inorganic and organic 

constituents in duplicate streambed- and suspended-sediment samples collected 

from sites on Leon Creek, San Antonio, Texas, 2012–14 .....................................................40

4. The mean and median relative percent difference (RPD) between duplicate 

stream-sediment samples collected from Leon Creek in San Antonio, Texas, 

2012–14 ........................................................................................................................................11

5. Comparison of U.S. Geological Survey (USGS) analytical laboratory results to 

the National Institute of Standards and Technology (NIST) reference materials ..........13
vii

6. Concentration of organic constituents in U.S. Geological Survey National Water 

Quality Laboratory quality-control samples included with sample sets for streamsediment samples collected from Leon Creek, San Antonio, Texas, 2012–14 .................53

7. Surrogate recoveries in streambed- and suspended-sediment samples 

collected from sites on Leon Creek, San Antonio, Texas, 2012–14 ...................................15

8. Concentrations of inorganic and organic constituents in streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, 

Texas, 2012–14 ............................................................................................................................65

9. The consensus-based sediment-quality guidelines of MacDonald and others 

(2000) that were used to evaluate the contaminant concentrations in streambedand suspended-sediment samples collected from Leon Creek in San Antonio, 

Texas, 2012–14 ............................................................................................................................17

10. Chi-square (C2) test statistics between proportional polychlorinated biphenyl 

(PCB) congener profiles of stream-sediment samples collected from sites on 

Leon Creek, San Antonio, Texas, 2007–9 and 2012–14 ........................................................28

11. Summary of mean and standard deviation (mean ± standard deviation) of Chisquare (C2

) test statistics between proportional polychlorinated biphenyl (PCB) 

congener profiles of stream-sediment samples collected from sites on Leon 

Creek, San Antonio, Texas, 2007–9 and 2012–14 ..................................................................31

Conversion Factors

International System of Units to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square kilometer (km2) 247.1 acre

square kilometer (km2) 0.3861 square mile (mi2)

Volume

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

liter (L) 2.113 pint (pt)

liter (L) 1.057 quart (qt)

liter (L) 0.2642 gallon (gal)

liter (L) 61.02 cubic inch (in3) 

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as °F = (1.8 × 

°C) + 32.
viii

Datum

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

Selected Abbreviations

AFB Air Force Base

AFCEC Air Force Civil Engineer Center 

DDD Dichlorodiphenyldichloroethane

DDE Dichlorodiphenyldichloroethylene

DDT Dichlorodiphenyltrichloroethane

FEQG Federal Environmental Quality Guidelines

IRL Interim reporting level

NAWQA National Water-Quality Assessment

NIST National Institute of Standards and Technology

NWQL National Water Quality Laboratory

PBDE Polybrominated diphenyl ether

PCB Polychlorinated biphenyl

PEC Probable effect concentration

RPD Relative percent difference

SQG Sediment-quality guideline

TCEQ Texas Commission on Environmental Quality

TEC Threshold effect concentration

USGS U.S. Geological Survey
Occurrence and Concentrations of Selected Trace 

Elements and Halogenated Organic Compounds in Stream 

Sediments and Potential Sources of Polychlorinated 

Biphenyls, Leon Creek, San Antonio, Texas, 2012–14

By Jennifer T. Wilson 

Abstract

The Texas Department of State Health Services issued 

fish consumption advisories in 2003 and 2010 for Leon Creek 

in San Antonio, Texas, based on elevated concentrations 

of polychlorinated biphenyls (PCBs) in fish tissues. The 

U.S. Geological Survey (USGS) measured elevated PCB 

concentrations in stream-sediment samples collected during 

2007–9 from Leon Creek at Lackland Air Force Base (now 

known as Joint Base San Antonio-Lackland; the sampling 

site at this base is hereinafter referred to as the “Joint Base 

site”) and sites on Leon Creek downstream from the base. 

This report describes the occurrence and concentrations of 

selected trace elements and halogenated organic compounds 

(pesticides, flame retardants, and PCBs) and potential 

sources of PCBs in stream-sediment samples collected from 

four sites on Leon Creek during 2012–14. In downstream 

order, sediment samples were collected from Leon Creek at 

northwest Interstate Highway 410 (Loop 410), Rodriguez 

Park, Morey Road, and Joint Base. The USGS periodically 

collected streambed-sediment samples during low flow and 

suspended-sediment samples during high flow. 

Trace element concentrations were low compared to 

the consensus-based sediment-quality guidelines (SQGs) 

for the threshold effect concentration (TEC) and probable 

effect concentration (PEC). Adverse effects to benthic biota 

are not expected at concentrations less than the TEC and are 

expected at concentrations greater than the PEC. No trace 

element concentrations were greater than the PEC in any of 

the samples. Trace element concentrations were greatest at the 

Morey Road and Joint Base sites and exceeded the TECs by 

41 and 27 percent, respectively. Trace element concentrations 

were lowest at the Rodriguez Park and Loop 410 sites and 

exceeded the TECs by 18 and 14 percent, respectively. 

Pesticides that have been banned for several decades 

are commonly detected in Leon Creek stream sediments, 

particularly the chlordane compounds. Chlordane 

compounds were detected in 84 percent of the samples 

and at every sample collection site. The samples collected 

from the Rodriguez Park site had the most pesticide 

compounds detected. Only samples collected from the 

Joint Base site had dichlorodiphenyldichloroethane 

(DDD), dichlorodiphenyldichloroethylene (DDE), or 

dichlorodiphenyltrichloroethane (DDT) concentrations greater 

than the TEC, and a few were also greater than the PEC. 

Flame retardants were found at every site on Leon Creek 

where stream sediments were collected; however, a few 

compounds were frequently detected in the laboratory reagent 

blanks so their detections in the environmental samples may 

not be from local sources. Consensus-based SQGs were not 

available for flame retardants so samples were compared 

to Environment Canada Federal Environmental Quality 

Guidelines (FEQGs). The concentrations of flame retardants 

generally were greater in the suspended-sediment samples 

than the streambed-sediment samples and greater than the 

FEQGs in many cases.

Eighteen PCB congeners were quantified in the sediment 

samples collected from Leon Creek. The samples collected 

from the Joint Base site had the most frequent PCB congener 

detections. Total PCB concentrations, computed as the sum of 

the 18 congeners by using the Kaplan-Meier method for leftcensored environmental data, were much smaller than the TEC 

of 59.8 micrograms per kilogram (μg/kg). When detected, the 

concentrations of total PCBs in the stream-sediment samples 

collected from Leon Creek during 2012–14 ranged from an 

estimated 0.2 to 8.7 μg/kg. 

Sediment samples collected from Leon Creek by the 

USGS during 2007–9 and 2012–14 at a total of eight sites 

following identical field and laboratory methods were 

evaluated to determine if potential PCB sources could be 

identified. Total PCB concentrations in the sediment samples 

collected upstream from the Joint Base site were low or 

nondetections; while concentrations in the samples collected 

on and downstream from the Joint Base site were greater. 

Congeners 180 and 138 constituted the greatest proportion 

of the PCB mixture in samples collected upstream from, on, 

and downstream from the Joint Base site. Upstream from the 

Joint Base site, congeners 180 and 138 constituted 50 percent 

and 35 percent respectively of the PCBs congeners found in 

the samples. On and downstream from the Joint Base site, 
2 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

congeners 180 and 138 constituted 80 percent and 13 percent 

respectively of the PCBs congeners found in the samples. 

Chi-square (C2) tests also indicate that samples collected from 

the Loop 410 site were statistically different from samples 

collected from the Joint Base site and sites downstream. The 

PCB congener pattern in the Leon Creek samples is most like 

the congener mixture in Aroclor 1260, which is chemically 

similar to the PCBs detected in the fish samples that resulted 

in the 2003 fish consumption advisory.

Introduction

Elevated concentrations of several trace elements and 

selected halogenated organic compounds (pesticides, flame 

retardants, and polychlorinated biphenyls [PCBs]) have been 

documented in streambed- and suspended-sediment samples 

collected from sites on Leon Creek in Bexar County, Texas, 

and in the San Antonio River, which receives inflows from 

Leon Creek (Wilson, 2011). Trace elements and halogenated 

organic compounds strongly associate with streambed and 

suspended sediments; the concentrations in the top few 

centimeters of bottom sediment and in suspended sediment are 

typically orders of magnitude greater than the concentration 

in the water column (Horowitz, 1991; Rostad and others, 

1995). Halogenated organic compounds include one or more 

halogen elements (chlorine, bromine, fluorine, and iodine) 

in their chemical structure, which makes them resistant to 

environmental degradation. Because these compounds break 

down slowly, they commonly persist in the environment for 

many years or decades; they are also resistant to metabolism 

and accumulate in food chains (Jones and de Voogt, 1999). 

Several of the flame retardants and PCBs were reported as 

congeners, which are compounds with similar base structures 

but unique numbers and positions of halogen substituents. 

Many of the elevated concentrations of trace elements and 

halogenated organic compounds were measured in sediment 

samples collected from Leon Creek at or downstream from 

the Lackland Air Force Base (now known as Joint Base 

San Antonio-Lackland). The Texas Department of State 

Health Services issued fish consumption advisories in 2003 

and 2010 for Leon Creek from the Old U.S. Highway 90 

bridge downstream to Southwest Military Drive (2003) 

and southwest Loop 410 (2010) for PCBs (figs. 1A and 1B) 

(Texas Department of Health, 2003; Texas Department of 

State Health Services, 2010). The U.S. Geological Survey 

(USGS), in cooperation with the San Antonio River Authority, 

collected additional streambed- and suspended-sediment 

samples (collectively referred to as stream-sediment samples) 

during 2012–14 to characterize trace elements and selected 

halogenated organic compounds in the upper reaches of Leon 

Creek, from northwest Interstate Highway 410 downstream 

to Joint Base San Antonio-Lackland. The analysis of streamsediment samples collected from sites upstream from Joint 

Base San Antonio-Lackland (fig. 2) also provides information 

about possible contaminant sources within the drainage area 

upstream from the base. 

Purpose and Scope

This report describes the concentrations of selected 

trace elements, pesticides, flame retardants, and PCBs 

in stream-sediment samples that were collected during 

2012–14 from four sites on Leon Creek, in Bexar County, 

Tex., compares these results with the results of samples 

collected during 2007–9 from a previous study of the same 

contaminants in stream-sediment samples (Wilson, 2011), 

and describes possible sources of PCBs. Streambed-sediment 

and suspended-sediment samples were collected during 

2012–14 from Leon Creek in Bexar County, Tex., on and 

upstream from Joint Base San Antonio-Lackland. The degree 

of contamination of each sample was assessed by comparing 

concentrations to consensus-based sediment-quality guidelines 

(SQGs). The frequencies at which the organic contaminants 

were detected in the samples were assessed. Comparisons 

of concentrations among sites were made to describe the 

occurrence and distribution of the contaminants. Eighteen 

PCB congeners were quantified in the sediment samples and 

used to evaluate potential sources of the PCBs. The KaplanMeier nonparametric statistic and Chi-square (C2

) test statistic 

were used for data analysis and interpretation. Because of 

the small size of the dataset, temporal trends in contaminant 

concentrations were not assessed. Major-element analyses are 

included in the report for completeness but are not discussed.
Introduction 3

Figure 1. Locations of the A, Leon Creek drainage area and fish consumption advisory stream segment and B, stream-sediment 

sampling sites, in Bexar County, Texas.

BEXAR COUNTY

EXPLANATION

Leon Creek drainage area

Current (2016) fish consumption advisory stream segment

 (Texas Department of State Health Services, 2010)

Municipal boundary 

Base modified from U.S. Geological Survey

1:24,000 scale digital data

Albers Equal Area Conic

Texas Centric Mapping System

North American Datum of 1983 

0

0 5 10 MILES

5 10 KILOMETERS

San Antonio

90

410

35

10

37

35

SOUTHWEST MILITARY DRIVE

LOOP 410

Medina River

Leon Creek

San Antonio River

A

29°40'

29°20'

98°40'

98°20'

BEXAR

COUNTY

TEXAS

Area

enlarged

on fig. 1B
4 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Figure 1. Maps showing locations of the A, Leon Creek drainage area and fish consumption advisory stream segment and B, streamsediment sampling sites, in Bexar County, Texas.—Continued

Base modified from U.S. Geological Survey

1:24,000 scale digital data

Albers Equal Area Conic

Texas Centric Mapping System

North American Datum of 1983 

San Antonio

JOINT BASE

SAN ANTONIOLACKLAND

JOINT BASE

SAN ANTONIOLACKLAND

JOINT BASE

SAN ANTONIOLACKLAND

JOINT BASE

SAN ANTONIOLACKLAND

SOUTHWEST MILITARY DRIVE

LOOP 410

MOREY ROAD

GROWDON ROAD

151

35

410

90

0 1 KILOMETER

0 1 MILE

Morey Road

LC068

IH 35

Leon Creek watershed

Military base

Air Force Civil Engineer Center streambed-sediment

 sampling site (Wilson, 2011, appendix 4)

U.S. Geological Survey (USGS) stream-sediment sampling 

 site, 2007–9 and 2012–14, and site identifier

USGS stream-sediment sampling site, 2007–9, and site

 identifier

EXPLANATION

IH, Interstate Highway

Area enlarged

BEXAR COUNTY

RODRIGUEZ

PARK

B

Leon Creek

Morey Road

Joint Base

LC040

LC063

LC024

Highway 90

LC066 Rodriguez Park

Loop 410

IH 35 

Quintana Road

Military Drive

LC065

LC015

LC067

LC068

98°38' 98°36' 98°34'

29°26'

29°24'

29°22'

29°20'
Introduction 5

Figure 2. Locations of stream-sediment sampling sites on Leon Creek in San Antonio, Texas, 2007–9 and 2012–14. 

Base modified from U.S. Geological Survey

1:24,000 scale digital data

Albers Equal Area Conic

Texas Centric Mapping System

North American Datum of 1983 

JOINT BASE

SAN ANTONIOLACKLAND

CAMP BULLIS

151

1604

16

90

410

10

35

0

0 2 4 MILES

2 4 KILOMETERS

IH 35

Quintana Road

Military Drive

Highway 90

Loop 410

Catchment area for sampling site—U.S. Geological Survey (USGS)

 station number and name (site identifier)

 USGS station number 08181435 Leon Creek

 at Loop 410 at San Antonio, Tex. (Loop 410 site)

 USGS station number 292443098364600, Leon Creek

 at Rodriguez Park, San Antonio, Tex. (Rodriguez Park site)

 USGS station number 292338098360501, Leon Creek at Morey

 Road, San Antonio, Tex. (Morey Road site)

 USGS station number 292240098353600, Leon Creek at Lackland

 Air Force Base Golf Course, San Antonio, Tex. (Joint Base site)

 Not part of 2012–14 study area

Military base

Municipal boundary

Stream-sediment sampling site, 2012–14, and site identifier—Rodriguez Park,

 Morey Road, and Joint Base sites were also sampled 2007–9

Stream-sediment sampling site, 2007–9, and site identifier—USGS station

 number and name (site identifier)

 USGS station number 08181445, Leon Creek at State Highway 90,

 San Antonio, Tex. (Highway 90 site)

 USGS station number 292156098350900, Leon Creek at Southwest

 Military Drive, San Antonio, Tex. (Military Drive site)

 USGS station number 292029098351400, Leon Creek at Quintana

 Road, San Antonio, Tex. (Quintana Road site)

 USGS station number 08181480, Leon Creek at Interstate Highway (IH) 35,

 San Antonio, Tex. (IH 35 site)

 

EXPLANATION

RODRIGUEZ PARK

Leon Creek

HuestaCreek

Lee Creek

French Creek

Huebner Creek

Culebra Creek

Pecan Cree

Leo

k

n Creek

Los Reyes Creek

Chimenea Creek

Helotes Creek

Leon Creek

French Creek

Huebner Creek

Culebra Creek

Pecan Cree

Leo

k

n Creek

Los Reyes Creek

HuestaCreek

Lee Creek

Chimenea Creek

Helotes Creek

Leon

Valley

Helotes

Fair Oaks

Ranch

San Antonio

Leon

Valley

Helotes

Grey

Forest

Fair Oaks

Ranch

Loop 410

Morey Road

Joint Base

Highway 90

Quintana Road

Military Drive

IH 35

Rodriguez Park

Loop 410

Morey Road

Joint Base

Highway 90

Quintana Road

Military Drive

IH 35

Rodriguez Park

98°35'

98°45'

29°35'

29°25'

BEXAR COUNTY

Study area
6 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Description of the Study Area and Sampling 

Sites

The study area consists of the drainage area of Leon 

Creek upstream from Interstate Highway 35 (figs. 1 and 2) 

in Bexar County, Tex. Most of Bexar County is coincident 

with the greater San Antonio, Tex., urban area; in 2014, San 

Antonio was the second largest city in Texas and the seventh 

largest city in the United States (U.S. Census Bureau, 2015). 

The sites where stream-sediment samples were collected 

during 2012–14 are located along Leon Creek at northwest 

Loop 410, in Rodriguez Park, at Morey Road, and on the 

southern part of Joint Base San Antonio-Lackland. The USGS 

station names and the short names used as the site identifiers 

for these four sampling sites are USGS station 08181435 Leon 

Creek at Loop 410 at San Antonio, Tex. (hereinafter referred 

to as the “Loop 410 site”); USGS station 292443098364600 

Leon Creek at Rodriguez Park, San Antonio, Tex. (hereinafter 

referred to as the “Rodriguez Park site”); USGS station 

292338098360501 Leon Creek at Morey Road, San Antonio, 

Tex. (hereinafter referred to as “Morey Road site”); and USGS 

station 292240098353600 Leon Creek at Lackland Air Force 

Base Golf Course, San Antonio, Tex. (hereinafter referred to 

as “the Joint Base site”). The sites where stream-sediment 

samples were collected during 2007–9 include Rodriguez 

Park, Morey Road, and Joint Base in addition to USGS station 

08181445 Leon Creek at State Highway 90, San Antonio, 

Tex. (hereinafter referred to as the “Highway 90 site”); 

USGS station 292156098350900 Leon Creek at Southwest 

Military Drive, San Antonio, Tex. (hereinafter referred to as 

the “Military Drive site”); USGS station 292029098351400 

Leon Creek at Quintana Road, San Antonio, Tex.(hereinafter 

referred to as the “Quintana Road site”); and USGS station 

08181480 Leon Creek at Interstate Highway 35, San Antonio, 

Tex.(hereinafter referred to as the “IH 35 site”). The 2007–9 

sediment results were included in the assessment of potential 

sources of PCBs. 

The catchment areas (fig. 2), which for the purposes of 

this report are defined (with one exception) as the drainage 

area between two sites, and land cover in the catchment area 

of each site sampled during 2012–14 are summarized (table 1). 

Unlike the catchment areas for the other sites, the catchment 

area for the Loop 410 site is not bounded by two sites; rather, 

it is the entire Leon Creek watershed upstream from where 

the Loop 410 site is located. Of all the sites, the Loop 410 

site has the largest catchment area with the lowest percentage 

of developed land cover. The Joint Base site has the smallest 

catchment area with the highest percentage of developed 

land cover. Kelly Air Force Base (AFB) operated during 

1971–2001 and was located mostly in the catchment area 

of the Joint Base site (figs. 1B and 2). After Kelly AFB was 

closed, parts of the installation were shifted to Lackland AFB, 

and an industrial complex currently (2016) known as Port 

San Antonio. Lackland AFB joined Fort Sam Houston, Camp 

Bullis, and Randolph AFB to form Joint Base San AntonioLackland in 2010 (Joint Base San Antonio, 2015). 

Table 1. Characteristics of the catchment area of each site where streambed- and suspended-sediment samples were collected from 

Leon Creek, San Antonio, Texas, 2012–14. Land cover data are from the National Land Cover Database 2011 (Homer and others, 2015).

[km2, square kilometers]

U.S. Geological 

Survey station 

number and name

(fig. 2)

Site 

identifier

Catchment

area

(km2)

Land cover 

(percent)

Developed Forest Shrubland Planted/

cultivated Herbaceous Wetlands Barren Water

08181435 Leon 

Creek at Loop 

410 at San 

Antonio, Tex. 

Loop 410 445.3 41.9 39.9 10.2 0.7 6.5 0.3 0.4 0.1

292443098364600 

Leon Creek at 

Rodriguez Park, 

San Antonio, Tex. 

Rodriguez 

Park

40.6 76.7 9.2 5.5 2.9 1.9 3.2 0.4 0.2

292338098360501 

Leon Creek at 

Morey Road, San 

Antonio, Tex.

Morey 

Road

14.4 63.7 2.4 7.9 13.3 2.7 10.0 0.0 0.0

292240098353600 

Leon Creek at 

Lackland Air 

Force Base Golf 

Course, San 

Antonio, Tex. 

Joint Base 12.4 87.4 1.5 4.6 1.5 2.8 1.8 0.4 0.0
Methods 7

As expected in most urban areas, there are numerous 

potential sources of contamination in the Leon Creek 

drainage area. The Texas Commission on Environmental 

Quality (TCEQ) Source Water Assessment Program identified 

abandoned municipal landfills and industrial wastewater 

outfalls as the two most common potential sources of 

contamination in the Leon Creek drainage area (Texas 

Commission on Environmental Quality, 2009; Wilson, 2011, 

fig. 3). The TCEQ listed PCBs as possible contaminants 

associated with both types of potential sources; furthermore, 

the Alamo Area Council of Governments (2005) compiled 

information such as approximate location, size, and years of 

operation of several closed landfills near the stream-sediment 

sampling sites. Although several potential sources of PCBs to 

Leon Creek were identified, none of the potential sources were 

sampled as part of this study.

Previous Studies

Federal and State agencies have measured concentrations 

of trace elements, pesticides, and PCBs along with other 

contaminants in biological and stream-sediment samples 

collected from Leon Creek. This section provides a brief 

overview of those sampling efforts. 

Previous USGS studies of Leon Creek in San Antonio 

included the collection of biological and streambed-sediment 

samples from the IH 35 site for trace elements, pesticides, 

and PCBs between 1995 and 2001 as part of the National 

Water-Quality Assessment (NAWQA) program (Wilson, 

2011, apps. 3.1 and 3.2). The USGS measured streambedand suspended-sediment contaminants at seven sites in Leon 

Creek during 2007–9 in a study of stream-sediment quality 

in Bexar County (Wilson, 2011). That study determined the 

greatest overall degree of sediment contamination relative to 

other streams in Bexar County was found in Leon Creek; the 

primary contaminants of concern were cadmium, chromium, 

chlordane, dichlorodiphenyldichloroethylene (DDE), and 

PCBs.

An Installation Restoration Program (U.S. Environmental 

Protection Agency, 2000, p. 4) was initiated at the former 

Kelly AFB in 1982 to assess and remediate contaminated sites 

on the base. The Air Force Civil Engineer Center (AFCEC), 

previously known as the Air Force Center for Environmental 

Excellence, oversees semiannual compliance sampling of 

Leon Creek sediment near the former Kelly AFB. Numerous 

sites on Leon Creek are sampled twice a year and analyzed 

for trace elements, pesticides, and PCBs. The results for 

samples collected during 1994–2008 are summarized in a 

previous USGS report (Wilson, 2011, table 6 and app. 4). 

Most of the USGS results for samples collected during 

2007–9 and 2012–14 are within the ranges of concentrations 

measured by AFCEC with a few exceptions where USGS 

concentrations are greater (zinc and one of the pesticides, 

dichlorodiphenyldichloroethane [DDD]); however, differences 

between the analytical methods used by the AFCEC and 

USGS laboratories hindered an indepth statistical analysis of 

the two datasets.

The Texas Department of State Health Services Seafood 

and Aquatic Life Group tests tissue samples to inform 

recreational fishermen of possible disease or contaminants 

in fish or other aquatic species. The agency tested fish 

collected in 2002 from several sites in Leon Creek for trace 

elements, pesticides, and PCBs. Their findings resulted in a 

fish consumption advisory for PCBs in 2003 for Leon Creek 

from Highway 90 downstream to Southwest Military Drive 

(fig. 1B) (Texas Department of Health, 2003). A second fish 

consumption advisory for PCBs was issued in 2010 for Leon 

Creek from Highway 90 downstream to southwest Loop 410 

(figs. 1 and 2; Texas Department of State Health Services, 

2010).

Methods

Three of the four sampling sites on Leon Creek where 

stream-sediment samples were collected during 2012–14 

were at the same locations where the USGS collected 

sediment samples during 2007–9. The fourth sampling site, 

Loop 410, is coincident with an existing USGS streamflowgaging station approximately 6 kilometers (km) upstream 

from Rodriguez Park (fig. 2). The streambed-sediment 

sampling sites were along stream reaches in depositional 

zones that could be sampled by wading the stream. Leon 

Creek is an ephemeral stream that only flows after storm 

events at and upstream from the Loop 410 site; it transitions to 

a perennial stream immediately upstream from the Rodriguez 

Park site. Where the stream is ephemeral, disconnected 

pools of water are present except during extreme droughts. 

The sampling sites were located where the streambed was 

continually submerged because comparability of wet to 

dry sediment chemistry is unreliable, especially for organic 

compounds (Shelton and Capel, 1994). In addition to 

collecting streambed-sediment samples, suspended-sediment 

samples were collected from the Loop 410, Rodriguez Park, 

and Morey Road sites (fig. 2). The suspended-sediment 

samples were collected to assess concentrations of sediment 

contaminants during storm events. The sediments in these 

samples included those introduced to the stream from recent 

runoff and streambed sediments that were resuspended during 

storm events and transported further downstream (Colby, 

1963; Mahler and others, 2006). As explained by Colby (1963, 

p. A2) “sediment particles continually change their positions 

in the flow; some fall to the streambed, and others are removed 

from the bed. Sediment deposits form locally or over large 

areas if the volume rate at which particles settle to the bed 

exceeds the volume rate at which particles are removed from 

the bed.”
8 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Sample Collection

Sampling began in November 2012 and was completed 

in July 2014. Streambed-sediment samples were collected 

from the beginning of the study and after each subsequent 

suspended-sediment sample (table 2). 

Streambed-Sediment Samples

The collection of streambed-sediment samples was based 

on the methods of the USGS NAWQA program (Shelton and 

Capel, 1994). The NAWQA streambed-sediment collection 

guidelines recommend collecting fine-grained particulates 

from 5 to 10 depositional zones during low-flow conditions, 

where each zone is approximately 100 meters (m) long, and 

the distance between depositional zones is reasonable for the 

scale of the river system. Depositional zones are locations 

in streams where the energy regime is low, and fine-grained 

particles accumulate in the streambed (Shelton and Capel, 

1994). Because many depositional zones potentially 

suitable for sampling were too deeply inundated to wade 

or inaccessible because of thick vegetation or steep banks, 

only 3 to 5 depositional zones totaling 230 to 500 m were 

sampled at each site during 2012–14 (table 2). All streambedsediment samples were collected by wading the stream; 

each depositional zone was approached by one or two field 

personnel from the downstream direction so as not to disturb 

the streambed sediment (fig. 3A). After rinsing precleaned 

sampling equipment with native water, surficial streambed 

sediment (about 1 centimeter) was collected from multiple 

depositional zones with a Teflon spoon and composited in a 

glass container. The total volume (wet) of streambed sediment 

collected from each stream reach was about 1 liter (L). 

Streambed-sediment samples were stored on ice immediately 

after collection and processed in the USGS office in San 

Antonio. 

Table 2. Streambed- and suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.

Site 

identifier

(table 1)

Total 

length 

of reach 

(meters)

Number of 

depositional 

zones

Type and number of samples collected per year

2012 2013 2014

Streambed 

sediment

Suspended 

sediment

Streambed 

sediment

Suspended 

sediment

Streambed 

sediment

Suspended 

sediment

Loop 410 360 4 1 0 3 3 1 1

Rodriguez Park 230 5 1 0 3 2 1 1

Morey Road 230 5 1 0 3 3 1 1

Joint Base 500 3 1 0 3 0 1 0

Figure 3. Streambed-sediment sample collection methods used at Leon Creek in San Antonio, Texas, 2012–14. A, Hydrologic technician 

collecting surficial streambed sediment from a depositional zone; and B, Hydrologic technician processing a surficial streambedsediment sample. 

A B
Methods 9

Streambed-sediment sample processing involved mixing 

and sieving the wet sediment (fig. 3B). Sieving the samples 

eliminated the grain-size variability that has been shown to 

affect trace-element and organic-compound concentrations 

in sediment samples (Horowitz and Elrick, 1987; Smith and 

others, 1988), allowing for more informative comparisons 

among samples. About half of the sample was sieved by using 

a 63-micrometer (μm) nylon-cloth sieve for analysis of major 

and trace elements. Sediment greater than 63 μm (the diameter 

differentiating larger, sand-size particles from smaller, 

clay- and silt-size particles) was discarded. The fine material 

(less than 63 μm) was transferred into 125-milliliter (mL) 

polypropylene jars and transported on ice to the USGS office 

in Austin, Tex., where they were freeze-dried, pulverized, and 

shipped to the USGS Mineral Resources Program Analytical 

Laboratories in Lakewood, Colorado, for analysis. The other 

half of the sample was sieved by using a 2.0-millimeter 

(mm) stainless-steel-mesh sieve on the opening of a 500-mL 

precleaned glass jar and analyzed for organic compounds. 

Coarse sediment (greater than 2.0 mm) was discarded. The 

samples for organic compound analyses were stored at 4 

degrees Celsius (°C) and shipped on ice to the USGS National 

Water Quality Laboratory (NWQL) in Lakewood, Colo., for 

analysis. 

Suspended-Sediment Samples

Suspended-sediment samples were collected during 

high-flow conditions resulting from storm events following the 

methods described in Mahler and Van Metre (2003) and Van 

Metre and others (2003). Stormwater runoff was collected in 

large-volume passive samplers and then filtered to isolate the 

suspended sediments in the stormwater. Two passive samplers 

were installed to collect suspended-sediment samples at 

each sampling site. The passive samplers consisted of a 25-L 

polyethylene bottle inside a cylindrical steel housing installed 

in or near the stream channel (figs. 4A and 4B). Each sampler 

had two water intake nozzles pointed upstream and an air 

vent line designed to collect “first flush” grab samples at the 

sampling sites when the stream level rose above the level of 

the intake nozzles. The intake nozzles were 0.6 m above the 

bottom of the cylinders. The air vent line allowed air in the 

bottle to leave as water flowed in and blocked outflow when 

the bottle was full so that water did not continue to cycle 

through the bottle. The bottle was removed from the passive 

sampler after the storm passed and the streamflow receded 

and transported on ice to the laboratory at the USGS office in 

Austin for processing. 

The processing of the stormwater runoff samples 

involved filtering the water to isolate the suspended 

sediments (fig. 4C). The sample was transferred from 

the 25-L sample bottle into a custom 50-L churn so the 

sample could be stirred constantly during subsampling and 

filtration. The samples were filtered through a 0.45-μm 

Teflon membrane to separate the sediment from the water. 

To enable water to readily pass through the filters, the Teflon 

membranes were sprayed with methanol before placing them 

on the filter holders. About two-thirds of the sample were 

filtered for organic compound analyses by using a stainlesssteel filter holder. The remaining third of the sample was 

filtered for analysis of major and trace elements by using 

an acrylic filter holder. After filtration, the sediment was 

gently scraped from the Teflon membranes and transferred 

into sample jars. Samples for organic analyses were placed 

into precleaned glass jars and shipped on ice to the NWQL 

for analysis. Samples for inorganic analyses were placed 

into polypropylene jars, freeze-dried, and pulverized before 

they were shipped to the USGS Mineral Resources Program 

Analytical Laboratories in Lakewood, Colo. 

Analytical Methods

Stream-sediment samples were analyzed for major and 

trace elements and halogenated organic compounds including 

pesticides, flame retardants, and PCBs. The USGS Mineral 

Resources Program Analytical Laboratories in Lakewood, 

Colo., analyzed the samples for major and trace elements. 

The NWQL analyzed the samples for halogenated organic 

compounds. 

Freeze-dried stream-sediment samples were analyzed 

for major and trace elements by using several analytical 

methods. Total carbon was analyzed by combustion with an 

automated carbon analyzer following methods described by 

Brown and Curry (2002); carbonate carbon was determined 

as carbon dioxide by coulometric titration following methods 

described by Brown and others (2002). Organic carbon was 

computed by the laboratory as the difference between total 

carbon and carbonate carbon. Samples for major and trace 

element analyses were digested completely by a mixture of 

hydrochloric, nitric, perchloric, and hydrofluoric acids and 

analyzed by inductively coupled plasma-mass spectrometry 

(Briggs and Meier, 2002). Concentrations of mercury 

were determined by continuous flow-cold vapor-atomic 

fluorescence spectrometry (Hageman, 2007). 
10 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Figure 4. Suspended-sediment sample collection methods used at Leon Creek in San Antonio, Texas, 2012–14. A, Passive sampler 

used to collect suspended-sediment samples; B, Hydrologic technician removing bottles from passive samplers after a storm; and 

C, Suspended sediment isolated on a Teflon membrane after filtration of a stormwater-runoff sample. 

B C

A

25-Liter

sample

bottle

Intake nozzles (2)

Debris deflector

Water-intake

lines (2)

Air

vent

line

Vent holes

Flow direction

Siphon brake

(trapped air space)

Intake/vent

pressure

difference
Methods 11

Wet stream-sediment samples were analyzed for 

halogenated organic compounds following a custom 

analytical method. Custom methods are methods that do 

not have a published method report at the time of sample 

analysis. The custom analytical method was chosen to 

replicate the analytical methods used in the previous USGS 

study of Bexar County sediments (Wilson, 2011) so that data 

from the past and present studies could be combined for data 

exploration and interpretation. The samples were extracted 

twice: (1) by using the ASE 200 accelerated-solvent extraction 

system (Dionex, Sunnyvale, Calif.) at a pressure of 13,800 

kilopascals with a water/isopropyl alcohol mixture (50:50, 

volume-to-volume ratio) at 120 °C, and (2) by using a water/

isopropyl alcohol mixture (20:80, volume-to-volume ratio) 

at 200 °C for 40 minutes each. Surrogate compounds were 

added to the sample prior to extraction to monitor laboratory 

preparation, matrix effects (Rowe and others, 2005; Geboy 

and Engle, 2011), and method performance. The extracts 

were analyzed by capillary-column gas chromatography/

mass spectrometry on an Agilent Technologies, Model 5975, 

with the mass spectrometer operated in the electron-capture, 

negative-ion mode by using ammonia as the reactant gas. The 

halogenated organic compounds were identified by selectedion monitoring of the ions of interest (Mark Burkhardt and 

Steven Zaugg, U.S. Geological Survey, National Water 

Quality Laboratory, written commun., July 2007). The NWQL 

was initially unable to identify DDD, DDE, and DDT in 

several of the samples because of matrix interference, and no 

results were reported. At the request of the author, the analyst 

reviewed the gas chromatography/mass spectrometry output 

for the samples with unreported values for these compounds. 

The individual sample-extracted ion chromatogram was 

overlaid with the method spikes-extracted ion chromatogram, 

allowing the analyst to identify shifts in the retention time 

and signal-to-noise ratios for the responses. This allowed the 

analyst to identify the presence of DDD, DDE, and DDT in 

the samples where they were initially unable to identify these 

compounds and change the unreported values to less than 

values. The updated less than values were then verified by 

using gas chromatography/electron-capture detection analysis 

of the archived extracts (Mary Olson, U.S. Geological Survey, 

National Water Quality Laboratory, written commun., April 

2014). The methods used for gas chromatography/electroncapture detection analysis are described in Noriega and others, 

2003. The results were assigned an “h” value-qualifier code 

indicating the compounds were identified and then verified by 

this second method. 

Quality Control

An assessment of data quality can be made based 

on the results of quality-control samples. Quality-control 

samples submitted to the analytical laboratories by project 

personnel included 7 streambed-sediment sample duplicates, 

2 suspended-sediment sample duplicates, National Institute 

of Standards and Technology (NIST) reference material 8704 

(Buffalo River Sediment; National Institute of Standards 

and Technology, 2000) for major and trace elements, and 

NIST standard reference material 1941b (Organics in Marine 

Sediment; National Institute of Standards and Technology, 

2015) for pesticides and PCBs. 

Duplicate samples are two samples that are considered to 

be essentially identical in composition and are used to provide 

information about variability in the sample collection and 

analytical processes (Mueller and others, 2015). Concurrent 

duplicate samples were collected from Leon Creek, 

meaning that two samples were collected by using identical 

methodology, and as closely together in time and space as 

possible (Horowitz and others, 1994). Duplicate sample results 

can be affected by sample heterogeneity, particularly when 

sediments are the sample media (Pirkey and Glodt, 1998). The 

relative percent difference (RPD) was calculated between each 

pair of sample results to provide a measure of variability by 

using the following equation: 

1 2

1 2

| | 100

( ) / 2

C C RPD

C C

− = × + (1)

where

C1 is the constituent concentration in the first 

sample, and 

C2 is the constituent concentration in the 

duplicate sample.

The RPDs of concentrations for inorganic and organic 

constituents are listed in table 3 (at end of report). The mean 

and median RPD between duplicate stream-sediment samples 

collected from Leon Creek in San Antonio during 2012–14 are 

summarized (table 4). The mean and median RPDs are similar 

for streambed- and suspended-sediment samples, indicating 

similar variability in the two sample collection processes. 

The comparison of duplicate sample results indicates 

greater variability in the halogenated organic compound 

Table 4. The mean and median relative percent difference (RPD) 

between duplicate stream-sediment samples collected from Leon 

Creek in San Antonio, Texas, 2012–14.

Category

Number 

of 

samples

Mean

RPD

Median

RPD

All duplicate samples 9 13 2.8

Streambed-sediment samples 7 13 2.2

Suspended-sediment samples 2 12 6.5

Major and trace elements 9 5.1 2.0

Halogenated organic compounds 9 42 29

Pesticides 9 60 49

Brominated flame retardants 9 40 29

Polychlorinated biphenyls (PCBs) 9 18 1.6
12 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

concentrations compared to the major and trace element 

concentrations. Within the halogenated organic compound 

duplicate sample results, the RPDs were greatest for the 

pesticides and lowest for the PCBs. The variability between 

sample types and analytical methods are similar to that of the 

previous USGS study of Bexar County sediments (Wilson, 

2011, p. 19).

Comparisons of analyses of reference materials by 

the USGS laboratories to the NIST concentration values 

generally indicate negative bias (that is, the measured 

concentrations were likely less than the actual concentrations) 

and the possibility of false negatives (concentrations 

reported as less than the applicable reporting level when 

they were likely larger than the applicable reporting level) 

during environmental sample analyses (table 5). Results 

for the analysis of the reference material 8704 (Buffalo 

River Sediment) by the USGS Mineral Resources Program 

Analytical Laboratories were within the range of uncertainty 

for 28 percent of the analyses, greater than the range of 

uncertainty for 2 percent of the analyses, and less than the 

range of uncertainty for 70 percent of the analyses. The 

NWQL results for the analysis of the standard reference 

material 1941b (Organics in Marine Sediment) were 

adjusted for NWQL laboratory reagent spike recoveries 

before comparison to the NIST concentration values. After 

adjustment, the laboratory results were within the range of 

uncertainty for 18 percent of the analysis, greater than the 

range of uncertainty for 10 percent of the analyses, and less 

than the range of uncertainty (many of which were less than 

the applicable interim reporting level) for 72 percent of the 

analyses. The interim reporting level, hereinafter referred to 

as the “IRL,” is a temporary reporting level used for new or 

custom schedules when long-term method detection limit data 

are unavailable, and a laboratory reporting level has not yet 

been established (U.S. Geological Survey, 2002, table 5). 

Quality control for the NWQL for the halogenated 

organic compound analyses consisted of analyzing a 

laboratory reagent blank and a laboratory reagent spike, 

along with monitoring recovery of surrogate compounds with 

each set of environmental samples. The samples collected 

from Leon Creek during 2012–14 were analyzed in eight 

different sets (table 6, at end of report). Halogenated organic 

compound concentrations less than their respective IRLs are 

hereinafter referred to as “nondetections” or “nondetected 

concentrations,” and concentrations equal to or greater 

than their respective IRLs are referred to as “detections” or 

“detected concentrations.” 

Laboratory reagent blank samples are used to monitor 

for impurities and contamination from reagents and glassware 

(Noriega and others, 2003). Two to five halogenated organic 

compounds were detected in each of the blank samples 

(table 6). Polybrominated diphenyl ether (PBDE) congeners 

47 and 99 were detected in all blank samples. PBDE congener 

100 and hexachlorobenzene were also detected frequently in 

the blanks. PBDE congeners 47, 99, and 100 were frequently 

detected in the laboratory reagent blanks included with the 

sediment samples in a previous USGS study of Bexar County 

sediments (Wilson, 2011). Whenever a halogenated organic 

compound was detected in a blank sample, the quantification 

of that same compound in the environmental samples from 

the same sample set was qualified as estimated with an “E” 

remark code and qualified as detected in the laboratory blank 

with a “v” value-qualifier code (Childress and others, 1999). 

Some of the detections of PBDE congeners 47, 99, and 100 

in the blank samples were at concentrations greater than their 

IRL of 0.1 microgram per kilogram (μg/kg). Detections of 

halogenated organic compounds in blank samples, particularly 

at concentrations equal to or greater than their IRLs, indicate 

positive bias and the possibility of false positives during 

environmental sample analyses; however, the detections in the 

environmental samples were at concentrations 3 to 280 times 

higher than the detected concentrations in their respective set 

blanks. Because concentrations measured in the environmental 

samples were much larger compared to those measured in the 

blank samples, no environmental data were rejected or adjusted 

on the basis of the results obtained from blank samples. 

On the basis of laboratory reagent spike recoveries, 

the analytical method performance and potential bias of 

environmental sample results were low compared to true 

environmental sample concentrations. The overall average 

spike recovery for the halogenated organic compounds was 

73.5 percent. The NWQL establishes annually acceptable 

spike recovery ranges on the basis of historical spike analyses. 

Spike recoveries were within acceptable recovery ranges for 

78.8 percent of the spike samples analyzed. Approximately 

three-fourths of the spike recoveries that were outside of their 

acceptable ranges were low. The compounds with the most 

frequent low spike recoveries were triclosan; PCB congeners 

146, 174, 177, 194, 206; and pentabromotoluene. Low spike 

recoveries for the PCB congeners were not common (only one 

congener low in one spike sample) in the laboratory reagent 

spikes included with the sediment samples in the previous 

Bexar County sediment study (Wilson, 2011). The PBDE 

congener 47 was the compound with the most frequent high 

spike recovery (also detected in all of the blank samples). 

The environmental sample results were adjusted for the 

laboratory reagent spike recoveries to assess the possible effect 

of the analytical method performance on the data interpretation. 

The environmental sample concentrations were raised or 

lowered as needed to represent a 100-percent spike recovery. 

Comparisons of the environmental sample concentrations 

among sites, sampling events, and to sediment-quality 

guidelines before and after spike adjustments indicated that the 

spike recovery rates had no apparent effect on the interpretation 

of the study results. The environmental sample results are 

therefore used in this report as received from the laboratory. 

Because laboratory reagent spikes are prepared using reagent 

water (deionized water that is continuously purged at the 

NWQL with ultrapure nitrogen and assumed to be void of the 

analytes of interest), any possible matrix effects associated with 

any organic matter, and (or) constituents other than the target 

constituent that might be present in the environmental samples, 
Methods 13

Table 5. Comparison of U.S. Geological Survey (USGS) analytical laboratory results to the National Institute of Standards and 

Technology (NIST) reference materials. 

[Reference material 8704 (Buffalo River Sediment) was used for the inorganic and carbon constituents; standard reference material 1941b (Organics in Marine 

Sediment) was used for the organic constituents; --, no data; <, less than; E, estimated; ±, plus or minus]

Constituent, units

Provider of reference material results and date of submittal to analytical laboratory

NIST USGS USGS 

-- 11/28/2012 4/9/2013

Calcium, milligrams per kilogram 26,410 ± 830 23,000 25,000

Magnesium, milligrams per kilogram 12,000 ± 180 11,000 11,000

Potassium, milligrams per kilogram 20,010 ± 410 18,000 19,000

Sodium, milligrams per kilogram 5,530 ± 150 5,400 5,600

Carbon (inorganic plus organic), percent 3.351 ± 0.017 3.4 3.1

Aluminum, milligrams per kilogram 61,000 ± 1,800 59,000 60,000

Barium, milligrams per kilogram 413 ± 13 400 380

Cadmium, milligrams per kilogram 2.94 ± 0.29 2.9 3.0

Cesium, milligrams per kilogram 5.83 ± 0.12 5.60 5.70

Chromium, milligrams per kilogram 121.9 ± 3.8 110 110

Cobalt, milligrams per kilogram 13.57 ± 0.43 13 13

Iron, milligrams per kilogram 39,700 ± 1,000 36,000 38,000

Lead, milligrams per kilogram 150 ± 17 140 140

Manganese, milligrams per kilogram 544 ± 21 530 550

Nickel, milligrams per kilogram 42.9 ± 3.7 42 39

Scandium, milligrams per kilogram 11.26 ± 0.19 11 10

Titanium, milligrams per kilogram 4,570 ± 200 3,900 3,400

Vanadium, milligrams per kilogram 94.6 ± 4 90 86

Zinc, milligrams per kilogram 408 ± 15 380 380

Antimony, milligrams per kilogram 3.07 ± 0.32 2.8 2.6

Arsenic, milligrams per kilogram 171 16 15

cis-Chlordane, micrograms per kilogram 0.85 ± 0.11 <0.292 0.092

cis-Nonachlor, micrograms per kilogram 0.378 ± 0.053 <0.132 E0.062

p,p'-DDD, micrograms per kilogram 4.66 ± 0.46 <2.652 <3.862

p,p'-DDE, micrograms per kilogram 3.22 ± 0.28 <1.322 0.312

p,p'-DDT, micrograms per kilogram 1.12 ± 0.42 <4.422, 3 <5.042, 3

trans-Chlordane, micrograms per kilogram 0.566 ± 0.093 <0.272 E0.092

trans-Nonachlor, micrograms per kilogram 0.438 ± 0.073 <0.132 <0.202

PCB congener 101, micrograms per kilogram 5.11 ± 0.34 <2.122 1.592

PCB congener 110, micrograms per kilogram 4.62 ± 0.36 <2.12 6.552

PCB congener 118, micrograms per kilogram 4.23 ± 0.19 2.962 E2.082

PCB congener 138, micrograms per kilogram 3.6 ± 0.28 3.432 4.882

PCB congener 146, micrograms per kilogram 1.22 ± 0.12 1.242 0.642

PCB congener 149, micrograms per kilogram 4.35 ± 0.26 1.112 2.072

PCB congener 170, micrograms per kilogram 1.35 ± 0.09 1.842 1.312

PCB congener 174, micrograms per kilogram 1.51 ± 0.39 1.242 E0.912

PCB congener 180, micrograms per kilogram 3.24 ± 0.51 3.142 E2.642

PCB congener 183, micrograms per kilogram 0.979 ± 0.087 1.272 E0.642

PCB congener 187, micrograms per kilogram 2.17 ± 0.22 1.852 E1.682

PCB congener 194, micrograms per kilogram 1.04 ± 0.06 1.092 E0.812

PCB congener 206, micrograms per kilogram 2.42 ± 0.19 2.562 E1.82

PCB congener 49, micrograms per kilogram 4.34 ± 0.28 <4.32, 3 <7.12, 3

PCB congener 52, micrograms per kilogram 5.24 ± 0.28 <1.972 <2.552

PCB congener 70, micrograms per kilogram 4.99 ± 0.29 <3.592 <5.82, 3

Thorium, milligrams per kilogram 9.07 ± 0.16 9 8

Uranium, milligrams per kilogram 3.09 ± 0.13 3.0 2.7 1

Not enough data to assign uncertainty.

2

Adjusted for spike recovery.

3

Nondetection with reporting limit above the NIST concentration and range of uncertainty, not included in calculations of percentage of USGS results outside 

of the NIST range of uncertainty.
14 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

are not accounted for by laboratory reagent spike recovery 

rates (Rowe and others, 2005). 

Surrogate compounds are added to the environmental 

samples at the time of extraction and are used to monitor 

the recovery and matrix effects of the analytical method. 

Surrogate recoveries are not used to correct concentrations 

because the surrogates do not chemically mimic all of the 

compounds in the laboratory method (Noriega and others, 

2003). The average surrogate recoveries were 54.5, 64.2, 

and 143.9 percent for 4,4 ́-dibromooctafluorobiphenyl, PCB 

congener 202-13C12, and p,p'-DDT-d8, respectively (table 7). 

Surrogate recovery control limits are established similarly to 

spike recoveries. Control limits define the range of acceptable 

surrogate recovery values for each compound (Noriega and 

others, 2003). Surrogate recoveries were within control limits 

of 20 to 104 percent for 4,4 ́-dibromooctafluorobiphenyl, 38 to 

110 percent for PCB congener 202-13C12, and 39 to 129 percent 

for p,p'-DDT-d8 for 76 percent of the sample analyses. Most 

of the surrogate recoveries that were outside of the acceptable 

range exceeded the control limits for the p,p'-DDT-d8 

surrogate. The NWQL checks and adjusts the method when 

surrogate recoveries are outside of the control limits.

Several factors can affect the analytical results reported 

by the NWQL for organic compounds. The IRLs for organic 

compounds were raised as the sediment mass available 

for analysis decreased, resulting in higher IRLs for some 

suspended-sediment samples, in particular. The NWQL used 

an “E” remark code to signify that the concentration was an 

estimated value for one or more possible reasons, and for 

most samples, at least one constituent was estimated. When 

an organic compound was detected in the blank sample, an “E” 

remark code and a “v” value-qualifier code were assigned to 

the results of that same compound in the environmental sample. 

Some organic compounds were assigned an “E” remark code 

and an “m” value-qualifier code because there was questionable 

precision or accuracy with the analytical method as a result 

of matrix interference or because they were highly variable 

compounds. Concentrations that were extrapolated because they 

were less than the lowest calibration standard, method range, or 

instrument range were assigned an “E” remark code and a “b” 

or “n” value-qualifier code (Childress and others, 1999). 

Information obtained from all of the quality-control 

samples indicates the variability was high for the halogenated 

organic compound method, particularly for the pesticides; 

however, the amount of variability was considered typical 

for sediment samples based on a comparable previous study 

(Wilson 2011). The concentrations of the reference materials 

were lower than expected for the trace elements and organic 

compounds. There were frequent detections of flame retardants 

in the laboratory reagent blanks, which is typical for the 

analytical method. The laboratory reagent spike recoveries were 

unusually low for some of the PCB congeners. The qualitycontrol data for trace elements indicate the concentrations 

measured for these constituents tend to be biased somewhat 

low but are considered acceptable. The quality-control data 

for organic compounds indicate there are bias and variability 

concerns associated with these data that must be considered 

when interpreting the results obtained from environmental 

samples. 
Methods 15

Table 7. Surrogate recoveries in streambed- and suspended-sediment samples collected from sites on Leon Creek, San Antonio, 

Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; PCB, polychlorinated biphenyl; p,p′-DDT, para,para’-dichlorodipheny

ltrichloroethane; SB, Bottom material; --, no data; SBQ, QC sample - Bottom material; SS, Suspended sediment; SSQ, QC sample - Suspended sediment]

Station 

number

Station 

name

Site 

identifier 

(table 1)

Date

Medium 

code 

(QC sample 

type)

NWQL 

set 

number

4,4′-dibromooctafluorobiphenyl, 

internal 

standard/

surrogate

(percent 

recovery)

PCB 

congener 

202-13C12, 

surrogate

(percent 

recovery)

p,p'-

DDT-d8, 

surrogate

(percent 

recovery)

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SB 201234302 -- 56.6 61.4

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SBQ 

(replicate)

201234302 -- 66.2 69.0

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 01/09/2013 SS 201312803 -- 59.9 83.5

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 02/07/2013 SB 201312803 -- 63.8 90.6

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 02/07/2013 SBQ 

(replicate)

201316313 -- 48.8 113

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 04/29/2013 SS 201316313 -- 58.0 171

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/14/2013 SB 201316313 -- 45.9 172

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/14/2013 SBQ 

(replicate)

201320406 -- 71.5 210

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/24/2013 SS 201320406 -- 78.7 261

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 06/25/2013 SB 201326608 -- 66.6 132

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 06/25/2014 SS 201425501 81.7 78.0 97.7

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 07/22/2014 SB 201432811 37.0 43.0 46.5

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 07/22/2014 SBQ 

(replicate)

201432811 47.6 49.1 51.4

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

11/15/2012 SB 201234302 -- 71.4 72.6

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

02/07/2013 SB 201312803 -- 54.9 65.4

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

04/29/2013 SS 201316313 -- 57.9 174

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

201316313 -- 59.9 187

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

05/14/2013 SB 201320406 -- 85.1 289

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

05/24/2013 SS 201320406 0.0 74.9 257

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

06/24/2013 SB 201326608 -- 74.7 144

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

06/25/2014 SS 201425501 80.8 94.9 112

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

07/21/2014 SB 201433804 49.4 51.3 58.4

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

11/15/2012 SB 201234302 -- 70.8 77.0

Table 7. Surrogate recoveries in streambed- and suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 

2012–14.

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; PCB, polychlorinated biphenyl; p,p'-DDT, para,para’-dichlorodiphenyl

trichloroethane; SB, Bottom material; --, no data; SBQ, QC sample - Bottom material; SS, Suspended sediment; SSQ, QC sample - Suspended sediment]
16 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 7. Surrogate recoveries in streambed- and suspended-sediment samples collected from sites on Leon Creek, San Antonio, 

Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; PCB, polychlorinated biphenyl; p,p′-DDT, para,para’-dichlorodipheny

ltrichloroethane; SB, Bottom material; --, no data; SBQ, QC sample - Bottom material; SS, Suspended sediment; SSQ, QC sample - Suspended sediment]

Station 

number

Station 

name

Site 

identifier 

(table 1)

Date

Medium 

code 

(QC sample 

type)

NWQL 

set 

number

4,4′-dibromooctafluorobiphenyl, 

internal 

standard/

surrogate

(percent 

recovery)

PCB 

congener 

202-13C12, 

surrogate

(percent 

recovery)

p,p'-

DDT-d8, 

surrogate

(percent 

recovery)

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

01/09/2013 SS -- Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

02/06/2013 SB 201312803 -- 57.2 82.8

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

02/06/2013 SBQ 

(replicate)

201316313 -- 60.0 202

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

04/29/2013 SS 201316313 -- 57.8 155

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/13/2013 SB 201320406 -- 81.1 290

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/24/2013 SS 201320406 -- 72.1 260

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/24/2013 SSQ 

(replicate)

201320406 -- 52.0 209

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2013 SB 201320406 -- 78.0 285

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2013 SBQ 

(replicate)

201320406 -- 74.4 275

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2014 SS 201425501 82.0 98.9 119

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

07/21/2014 SB 201433804 53.2 56.0 68.7

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 11/16/2012 SB 201234302 -- 77.9 82.7

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 11/16/2012 SBQ 

(replicate)

201234302 -- 35.0 37.7

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 02/06/2013 SB 201312803 -- 52.7 84.1

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 05/13/2013 SB 201316313 -- 58.7 209

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 06/24/2013 SB 201320406 -- 76.5 287

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 07/21/2014 SB 201433804 59.1 60.2 69.0

88480206 USGS Central Tex. PO at 

Ferguson Ln, Austin, Tex.

-- 11/28/2012 SBQ 

(standard 

reference 

material)

201235310 -- 73.2 104

88480206 USGS Central Tex. PO at 

Ferguson Ln, Austin, Tex.

-- 04/09/2013 SBQ 

(standard 

reference 

material)

201316313 -- 30.1 83.2
Concentrations and Occurrence of Selected Trace Elements and Halogenated Organic Compounds 17

Concentrations and Occurrence 

of Selected Trace Elements and 

Halogenated Organic Compounds 

Concentrations of selected trace elements and 

halogenated organic compounds in the stream-sediment 

samples (table 8, at end of report) were compared to the 

consensus-based sediment-quality guidelines (SQGs) 

published by MacDonald and others (2000) (table 9). The 

SQGs evaluate the potential toxicity of bed sediments to 

benthic biota (sediment-dwelling organisms). The guidelines 

were developed for streambed sediment but not for suspended 

sediment; however, the suspended-sediment sample 

concentrations were evaluated relative to SQGs to enable 

comparisons between sites. Two SQG concentration levels 

are used: (1) a lower level, the threshold effect concentration 

(TEC), below which harmful effects to benthic biota are 

not expected, and (2) a higher level, the probable effect 

concentration (PEC), above which harmful effects are expected 

to occur frequently. Samples with concentrations between the 

TEC and PEC are neither predicted to be toxic nor predicted 

to be nontoxic to benthic biota. The sediment screening levels 

used by the TCEQ’s Ecological Assessment Program are 

identical to the PECs of MacDonald and others (2000) (Texas 

Commission on Environmental Quality, 2015). The occurrence 

of selected halogenated organic compounds was evaluated by 

assessing the frequency at which they were detected. 

The passive suspended-sediment samplers did not always 

work correctly. For unknown reasons, the passive sampler at 

the Rodriguez Park site did not fill during the storm on January 

9, 2013. There also was not enough sediment recovered after 

filtration for both inorganic and organic analyses of the samples 

collected from the Morey Road and Loop 410 sites during 

the storm on January 9, 2013. As a result, both samples were 

filtered by using only the stainless-steel filter holder because 

the organic contaminants were of primary interest in this study; 

neither of the samples was filtered with the acrylic filter holder 

for the major and trace elements. The NWQL requests 10 grams 

(g; dry mass) of sediment for the organic analyses to achieve 

the lowest reporting levels. The reporting levels of both samples 

were raised by the laboratory because of the low sample masses 

(0.15 g at Morey Road and 1.13 g at Loop 410). The small 

mass of sediment recovered from the Morey Road suspendedsediment sample, which was one order of magnitude lower than 

the mass of sediment recovered in all other suspended-sediment 

samples, resulted in very high reporting levels (raised three 

orders of magnitude). For this reason, the organic compound 

laboratory results for the Morey Road suspended-sediment 

sample collected during the storm on January 9, 2013, were 

rejected and are not included in this report. 

Trace Elements

Trace elements in stream sediments are derived from 

naturally weathered rock and soil particles; they also may 

be derived from pesticides, paint, sewage, fertilizers, mining 

activities, and the burning of fossil fuels (Senesil and 

others, 1999). Consensus-based sediment-quality guidelines 

(MacDonald and others, 2000) (TECs and PECs) are 

depicted along with the concentrations of arsenic, cadmium, 

chromium, copper, lead, mercury, nickel, and zinc measured in 

environmental samples (fig. 5). No trace element concentrations 

were greater than the applicable PEC in any of the samples, and 

concentrations of copper, lead, and mercury were less than the 

applicable TEC in all samples. Chromium was most frequently 

detected at concentrations greater than the TEC (30 percent 

of all analyses). Arsenic, cadmium, and zinc were detected 

at concentrations greater than the TEC, albeit in a relatively 

low percentage of samples (between 4 and 18 percent). The 

percentage of samples with concentrations greater than the TEC 

for all eight trace elements was greatest at the Morey Road site 

(41 percent) followed by the Joint Base (27 percent), Rodriguez 

Park (18 percent), and Loop 410 (14 percent) sites. 

Table 9. The consensus-based sediment-quality guidelines 

of MacDonald and others (2000) that were used to evaluate the 

contaminant concentrations in streambed- and suspendedsediment samples collected from Leon Creek in San Antonio, 

Texas, 2012–14.

[mg/kg, milligram per gram; μg/kg, microgram per kilogram; DDD, 

dichlorodiphenyldichloroethane; DDE, dichlorodiphenyldichloroethylene; 

DDT, dichlorodiphenyltrichloroethane; PCB, polychlorinated biphenyl]

Constituent Threshold effect 

concentration

Probable effect 

concentration

Trace elements (mg/kg)

Arsenic 9.79 33.0

Cadmium 0.99 4.98

Chromium 43.4 111

Copper 31.6 149

Lead 35.8 128

Mercury 0.18 1.06

Nickel 22.7 48.6

Zinc 121 459

Halogenated organic compounds (μg/kg)

Chlordane1 3.24 17.6

Dieldrin 1.90 61.8

DDD 4.88 28.0

DDE 3.16 31.3

DDT 4.16 62.9

Total PCB2 59.8 676

1

Chlordane concentrations are computed as the sum of cis-chlordane, transchlordane, cis-nonachlor, and trans-nonachlor.

2

Total PCB concentrations are computed as the sum of the concentrations 

of the following 18 PCB congeners: 49, 52, 70, 101, 110, 118, 138, 146, 149, 

151, 170, 174, 177, 180, 183, 187, 194, and 206.
18 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Figure 5. The comparison of consensus-based sediment-quality guidelines (MacDonald and others, 2000) with concentrations of trace 

elements in streambed- and suspended-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14. Trace-element concentration, in milligrams per kilogram (mg/kg)

0

40

80

120

160

0

5

10

15

20

25

30

35

5

10

15

20

25

0

0

10

20

30

40

50

60

0

0.02

0.04

0.06

0.08

0.10

0

0.5

1.0

1.5

2.0

0

10

20

30

40

0

2

4

6

8

10

12

14

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Site identifier (fig. 2)

[PEC 4.98 mg/kg]

[PEC 111 mg/kg]

[PEC 128 mg/kg]

[PEC 33 mg/kg]

[PEC 48.6 mg/kg]

[PEC 149 mg/kg]

[TEC 0.18 mg/kg,

PEC 1.06 mg/kg]

[PEC 459 mg/kg]n/a n/a n/a n/a

n/a n/a n/a n/a

Cadmium

Chromium

Lead

Arsenic

Nickel

Copper

Mercury

Zinc

Low-flow

streambed

sediment

High-flow

suspended

sediment

Low-flow

streambed

sediment

High-flow

suspended

sediment

[TEC, threshold effect concentration; PEC, probable effect concentration

n/a, not applicable because suspended-sediment samples were not collected] 

TEC

TEC

TEC

TEC

TEC

TEC

TEC
Concentrations and Occurrence of Selected Trace Elements and Halogenated Organic Compounds 19

Halogenated Organic Compounds

The halogenated organic compounds discussed in this 

report are associated with human activities, unlike the trace 

elements that can occur naturally. In the United States, the 

production, sale, or use of many of these compounds (certain 

pesticides, flame retardants, and PCBs) were banned or 

restricted because of their persistence in the environment, 

detrimental effects on plant and animal life, or both (Agency 

for Toxic Substances and Disease Registry, 1994, 2000, and 

2015); other pesticides and flame retardants have not been 

banned or restricted at the time of this report (2016). 

Concentrations of halogenated organic compounds can 

be related to the percentage of organic carbon in sediment 

samples because organic compounds sorb to the organic matter 

in sediments (Chiou and others, 1979; Karickhoff and others, 

1979; Jones and de Voogt, 1999). The percentage of organic 

carbon is different in some of the streambed-sediment samples 

compared to the percentage of organic carbon in suspendedsediment samples collected from Leon Creek (fig. 6). Also, 

the percentages of organic carbon are generally lower in the 

streambed-sediment samples collected from the Loop 410 site 

compared to the percentages of organic carbon in streambedsediment samples collected from downstream sites. A 

Kruskall-Wallis analysis of variance test (Iman and Conover, 

1983) was used to determine that the percentages of organic 

carbon in the samples collected from each site have equivalent 

distributions; the attained significance level (p-value) was 

0.27. Because the percentage of organic carbon did not vary 

significantly (p-value less than 0.05 is statistically significant) 

among the samples from the eight sites in the watershed, the 

concentrations of halogenated organic compounds were not 

normalized for organic carbon.

Pesticides

The pesticides assessed in this study are synthetic, 

halogenated organic compounds. The chlordane compounds 

(cis-chlordane, trans-chlordane, cis-nonachlor, and transnonachlor), which were banned in 1988 (Agency for Toxic 

Substances and Disease Registry, 1994), were the most 

frequently detected pesticides; they were detected in 84 

percent of the samples and at every sample collection site 

(fig. 7). The samples with the largest number of pesticide 

compounds detected were collected from the Rodriguez Park 

site; however, it should be considered that three fewer samples 

were collected from the Joint Base site compared to all other 

sites. Neither dichlorodiphenyltrichloroethane (DDT) nor 

its breakdown products, DDD and DDE, were detected in 

the samples collected from the Loop 410 site; however they 

were found in samples collected from the sites downstream. 

Cyfluthrin, a synthetic pyrethroid insecticide, was the most 

frequently detected pesticide and was not banned for use at 

the time of sample collection; it was found in 53 percent of 

the samples and at every sample collection site. Overall, there 

were fewer detections of the pesticides that are not banned 

compared to the banned or restricted-use pesticides in the 

samples collected from every site except Loop 410.

Figure 6. The percentage of organic carbon in streambed- and 

suspended-sediment samples collected from Leon Creek, San 

Antonio, Texas, 2007–9 and 2012–14.

0

1

2

3

4

5

Organic carbon, in percent

Site identifier (fig. 2)

Loop 410

Rodriguez Park

Morey Road

Joint Base

Highway 90

Military Drive

Quintana Road

IH 35

EXPLANATION

Streambed-sediment sample—Samples collected

 2007–9 are gray symbols. Samples collected 

 2012–14 are nongray symbols

Suspended-sediment sample—Samples collected

 2007–9 are gray symbols. Samples collected 

 2012–14 are nongray symbols

IH, Interstate Highway
20 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Concentrations of chlordane, dieldrin, DDD, DDE, and 

DDT measured in sediment samples were compared to the 

consensus-based SQGs in MacDonald and others (2000) 

(table 9). Chlordane concentrations, which were computed as 

the sum of cis-chlordane, cis-nonachlor, trans-chlordane, and 

trans-nonachlor, were greater than the TEC for 23 percent 

of the stream-sediment samples (fig. 8). The concentration 

of chlordane exceeded the TEC most frequently in the 

streambed-sediment samples collected from the Joint Base 

site. All of the dieldrin concentrations in the stream-sediment 

samples collected from Leon Creek were less than the TEC 

value of 1.9 μg/kg (table 8). The concentration of DDD 

exceeded the TEC in three samples with one sample collected 

from the Joint Base site greater than the PEC. All of the 

samples collected from the Joint Base site had concentrations 

of DDE greater than the TEC but less than the PEC. Three 

samples collected from the Joint Base site had concentrations 

of DDT greater than the TEC with two of those concentrations 

also greater than the PEC. None of the samples collected from 

the Loop 410, Rodriguez Park, or Morey Road sites had DDD, 

DDE, or DDT concentrations greater than the TEC. 

In short, pesticides that have been banned for several 

decades are commonly detected in Leon Creek stream 

sediments, particularly the chlordane compounds. Most 

of the pesticide concentrations were low except for some 

samples collected from the Joint Base site, where DDD and 

DDT were found at levels greater than the higher SQG (PEC). 

Whereas the frequent detections of pesticides in the Leon 

Creek stream sediments are notable, the few concentrations 

that exceed higher SQGs at the Joint Base site are of most 

concern. 

Figure 7. Detection frequencies of pesticides in streambed- and suspended-sediment samples, by site (table 1), collected from Leon 

Creek, San Antonio, Texas, 2012–14.

0 20 40 60 80 100 0 20 40 60 80 100

0 20 40 60 80 100 0 20 40 60 80 100

Detections, in percent

Pesticides

Detections, in percent

Dieldrin

Hexachlorobenzene*

cis-Chlordane

trans-Chlordane

cis-Nonachlor

trans-Nonachlor

DDT

DDD

DDE

alpha-Endosulfan

Chlorpyrifos

Cyfluthrin

DCPA

lambda-Cyhalothrin

Tefluthrin

Triclosan*

Methyl triclosan

Desulfinylfipronil

Fipronil sulfide

Pentachloroanisole

(n=9) (n=8) (n=8) (n=5)

Loop 410 Rodriguez Park Morey Road Joint Base

[n, number of samples; DDT, dichlorodiphenyltrichloroethane; DDD, dichlorodiphenyldichloroethane;

DDE, dichlorodiphenyldichloroethylene; DCPA, dimethyltetrachloro terephthalate; *, compounds detected

in laboratory reagent blanks]

Banned or

restricted

use 

Not banned

at time of

sample

collection 
Concentrations and Occurrence of Selected Trace Elements and Halogenated Organic Compounds 21

Flame Retardants

Brominated flame retardants are halogenated 

organic compounds that are added to plastics, foams, and 

fabrics to increase the fire resistance of products such 

as electronics, automobiles, clothing, and furniture. The 

compounds are not chemically bound to the products to 

which they are added, making them likely to leach out 

of these products. Many brominated flame retardants are 

persistent toxic chemicals that bioaccumulate (Segev and 

others, 2009). In 2006, the U.S. Environmental Protection 

Agency restricted the manufacturing, importing, or 

processing of pentabromodiphenyl ether (pentaBDE) and 

octabromodiphenyl ether (octaBDE), which are commercial 

mixtures of PBDE congeners (U.S. Environmental 

Protection Agency, 2014). The stream-sediment samples 

collected from Leon Creek during 2012–14 were analyzed 

for 10 PBDE congeners plus 3 other brominated flame 

retardants: dechlorane plus, pentabromotoluene, and 

1,2-bis(2,4,6-tribromophenoxy) ethane (TBE). Brominated 

flame retardants were found at every site on Leon Creek 

where stream sediments were collected (fig. 9); however, 

some compounds (PBDEs 47, 99, and 100) were frequently 

detected in the laboratory reagent blanks so their detections 

Figure 8. The comparison of consensus-based sediment-quality guidelines (MacDonald and others, 2000) with concentrations of 

pesticides in streambed- and suspended-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14. Pesticide concentration, in micrograms per kilogram (μg/kg)

0

1

2

3

4

5

6

7

8

9

10

0

5

10

15

20

25

0

10

20

30

40

50

60

0

20

40

60

80

100

120

140

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Site identifier (fig. 2) n/a n/a

n/a n/a

DDD

DDE

Chlordane

DDT

Low-flow

streambed

sediment

High-flow

suspended

sediment

Low-flow

streambed

sediment

High-flow

suspended

sediment

EXPLANATION

Sediment sample collected from Leon Creek for 

 pesticide concentration

 Detection

 Nondetection at interim reporting level

TEC, Threshold effect concentration

PEC, Probable effect concentration

DDD, Dichlorodiphenyldichloroethane

DDE, Dichlorodiphenyldichloroethylene

DDT, Dichlorodiphenyltrichloroethane

n/a, not applicable because suspended-sediment

 samples were not collected

TEC

TEC

TEC

TEC

PEC

PEC

[PEC 17.6 μg/kg]

[PEC 31.3 μg/kg]
22 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

in the environmental samples may not be from local sources. 

Dechlorane plus and PBDE 153 were the most frequently 

detected compounds.

Consensus-based SQGs were not available for 

brominated flame retardants so samples were compared 

to Environment Canada Federal Environmental Quality 

Guidelines (FEQGs), which were developed for the protection 

of benthic and pelagic aquatic life (Environment Canada, 

2013). Environment Canada recommended an FEQG of 

0.4 μg/kg for PBDE congeners 99 and 100. The concentrations 

of PBDE 99 exceed the FEQG in two streambed-sediment 

samples collected from the Loop 410 site and three streambedsediment samples collected from the Joint Base site (fig. 10). 

The concentrations of PBDE 99 exceed the FEQG in all 

of the suspended-sediment samples. The concentrations of 

PBDE 100 are less than the FEQG in all of the streambedsediment samples. All of the suspended-sediment samples 

except one collected from the Morey Road site have 

concentrations of PBDE 100 greater than the FEQG. The 

concentrations of PBDE 99 and PBDE 100 generally were 

greater in the suspended-sediment samples collected during 

high flow compared to the concentrations of these constituents 

measured in streambed-sediment samples collected during 

low flow. 

Although flame retardants were frequently detected in the 

Leon Creek stream-sediment samples at all sites, there may 

be some laboratory contamination for PBDEs 47, 99, and 100 

based on the detections of these constituents in the laboratory 

reagent blanks. The concentrations of flame retardants 

generally were greater in the suspended-sediment samples than 

the streambed-sediment samples and were greater than the 

FEQG in many cases. Flame retardants in Leon Creek stream 

sediments are of moderate concern based on their frequent 

occurrence and concentrations in suspended sediments.

Polychlorinated Biphenyls

Polychlorinated biphenyls were first synthesized in the 

early 1930s and have had widespread industrial uses, primarily 

as plasticizers, hydraulic lubricants, and dielectric fluids in 

electrical capacitors (Smith and others, 1988). Adverse humanhealth effects and cancer in animals have been associated 

with exposure to PCBs. PCBs have not been manufactured 

in the United States since 1977, and their use was banned in 

1979 (Agency for Toxic Substances and Disease Registry, 

2000). PCBs consist of as many as 209 theoretically possible 

congeners, with various numbers and positions of chlorine 

Figure 9. Detection frequencies of brominated flame retardants in streambed- and suspended-sediment samples, by site (table 1), 

collected from Leon Creek, San Antonio, Texas, 2012–14. 

0 20 40 60 80 100 0 20 40 60 80 100

0 20 40 60 80 100 0 20 40 60 80 100

Detections, in percent

Detections, in percent

Dechlorane plus

PBDE 47*

PBDE 66

PBDE 85

PBDE 99*

PBDE 100*

PBDE 138

PBDE 153

PBDE 154

PBDE 183

Pentabromotoluene

TBE

Brominated flame retardants

(n=9) (n=8) (n=8) (n=5)

Loop 410 Rodriguez Park Morey Road Joint Base

[n, number of samples; PBDE, polybrominated diphenyl ether; TBE, 1,2-bis(2,4,6-tribromophenoxy) ethane;

*, compounds detected in laboratory reagent blanks]
Concentrations and Occurrence of Selected Trace Elements and Halogenated Organic Compounds 23

atoms attached to the biphenyl structure. Each congener has 

been assigned a congener number that generally increases 

with increasing chlorination of the biphenyl structure 

(Ballschmiter and Zell, 1980). Larger congeners tend to 

sorb strongly to solids such as sediments, whereas smaller 

congeners are more likely to volatilize (Eisenreich and others, 

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

The NWQL quantified 18 common PCB congeners in the 

stream-sediment samples collected from Leon Creek during 

2012–14. The smaller PCB congeners (49, 52, 70, and 101) 

were not detected in any of the stream-sediment samples 

collected from Leon Creek (table 8). PCB congener 110 was 

detected only in samples collected from the Joint Base site, 

and PCB 118 was detected only in samples collected from the 

Rodriguez Park and Joint Base sites (fig. 11). PCB congeners 

149 and 151 were not detected in any samples collected from 

the Loop 410 site but were detected at the three other sites. 

PCB congeners 170 through 206 were detected at all four 

sites, with the most detections in the Joint Base samples and 

the fewest detections in the Loop 410 samples. Overall, the 

samples collected from the Joint Base site had the most PCB 

congener detections.

MacDonald and others (2000) published consensusbased SQGs for total PCBs (table 9). Total PCBs in the Leon 

Creek stream-sediment samples were computed as the sum 

of the 18 reported congeners (table 8) by using the KaplanMeier method for computing summations that include 

nondetections (Helsel, 2009). The Kaplan-Meier method is 

a nonparametric statistical method that was developed for 

evaluating right-censored survival data of people older than 

a certain age in medical and industrial statistics that has 

been modified for left-censored environmental data where 

nondetections are common. Right and left censored refers 

to a statistical treatment of extreme values. In right censoring, 

a data point larger than a certain value of “X” is replaced 

with a value of “greater than X,” whereas in left censoring, 

Figure 10. The comparison of Environment Canada (2013) Federal Environmental Quality Guidelines with concentrations of brominated 

flame retardants in streambed- and suspended-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14. Brominated flame retardant concentration, in micrograms per kilogram (μg/kg) 

0

0.5

1.0

1.5

2.0

0

2

4

6

8

10

Site identifier (fig. 2)

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Loop 410

Rodriguez Park

Morey Road

Joint Base

Low-flow

streambed

sediment

High-flow

suspended

sediment

Low-flow

streambed

sediment

High-flow

suspended

sediment

FEQG

FEQG

(23.8) (6.25) n/a

n/a

PBDE 99 PBDE 100

EXPLANATION

Sediment sample collected from Leon Creek for brominated

 flame retardant concentration

 Detection

 Nondetection at interim reporting level

Concentration value off scale 

PBDE, Polybrominated diphenyl ether

FEQG, Federal Environmental Quality Guideline (Environment Canada, 2013)

n/a, not applicable because suspended-sediment samples were not collected

(6.25)
24 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

a data point smaller than a certain value of “Y” is replaced 

with a value of “less than Y.” The Kaplan-Meier method 

computes the cumulative distribution function for estimating 

sums, means, and variances of a dataset with nondetections. 

All concentrations of total PCBs in the stream-sediment 

samples collected from Leon Creek during 2012–14 are 

much smaller than the TEC of 59.8 μg/kg (table 9). When 

detected, the concentrations of total PCBs in the streamsediment samples collected from Leon Creek during 2012–

14 ranged from an estimated 0.2 to 8.7 μg/kg (table 8).

Briefly, PCBs (particularly the large congeners) were 

detected occasionally in samples collected from the Loop 

410 site, commonly at the Rodriguez Park and Morey 

Road sites, and frequently at the Joint Base site. All of the 

PCB detections were at very low concentrations, about 

an order of magnitude lower than the lower SQG (TEC). 

However, results from the quality-control samples indicated 

negative or low bias (tables 5 and 6) for the PCB congener 

concentrations, which may have resulted in slightly 

lower reported concentrations than actual environmental 

concentrations.

Potential Sources of Polychlorinated 

Biphenyls

This report focuses primarily on PCBs because 

concentrations in Leon Creek are greater than other streams in 

Bexar County (Wilson, 2011), and fish consumption advisories 

in Leon Creek have been linked to PCBs (Texas Department 

of State Health Services, 2010). Sediment samples collected 

from Leon Creek by the USGS during 2007–9 and 2012–14 

at a total of eight sites (fig. 2) following identical field and 

laboratory methods were evaluated to determine if potential 

PCB sources could be identified. 

Modern releases of PCB to the environment have 

essentially stopped since manufacturing ceased in 1977 

(Agency for Toxic Substances and Disease Registry, 2000), 

and present-day detections of PCBs are often derived from 

areas of historical PCB contamination. The compositions of 

PCB mixtures in the environment can be affected by processes 

such as volatilization, chemical or biological transformation, 

and bioaccumulation. The lower chlorinated congeners 

Figure 11. Detection frequencies of polychlorinated biphenyl congeners in streambed- and suspended-sediment samples, by site 

(table 1), from Leon Creek, San Antonio, Texas, 2012–14.

0 20 40 60 80 100 0 20 40 60 80 100

0 20 40 60 80 100 0 20 40 60 80 100

Detections, in percent

Detections, in percent

Polychlorinated biphenyl (PCB) congeners

PCB 110

PCB 118

PCB 138

PCB 146

PCB 149

PCB 151

PCB 170

PCB 174

PCB 177

PCB 180*

PCB 183

PCB 187

PCB 194

PCB 206

(n=9) (n=8) (n=8) (n=5)

Loop 410 Rodriguez Park Morey Road Joint Base

[n, number of samples; *, compound detected in a laboratory reagent blank]
Potential Sources of Polychlorinated Biphenyls 25

are more susceptible to alteration than higher chlorinated 

congeners because of differences in chemical properties 

such as solubility, partition coefficients, and vapor pressures 

(Agency for Toxic Substances and Disease Registry, 2000). 

Previous studies of PCB degradation in stream sediments 

indicate concentrations can be appreciably lower after one 

to two decades (Van Metre and others 1998; Sinkkonen and 

Paasivirta, 2000). The alteration of PCB mixtures in the 

environment is a concern when comparing recent to historical 

levels; however, this same issue does not persist when 

comparing samples collected within the same decade.

Total PCB concentrations in the streambed-sediment 

samples collected from Loop 410 downstream to Morey 

Road were less than the PCB reporting levels or low 

relative to total PCB concentrations measured in samples 

collected from sites farther downstream (fig. 12). Lower 

total PCB concentrations were measured in the suspendedsediment samples collected from the Loop 410, Rodriguez 

Park, and Morey Road sites upstream from the Joint Base 

compared to the total PCB concentrations measured in 

suspended-sediment samples collected from the IH 35 site. 

There appears to be an additional source of PCBs to the 

stream sediments between the Morey Road and the Joint 

Base sample collection sites based on the higher total PCB 

concentrations in the stream-sediment samples collected from 

the Joint Base, Military Drive, Quintana Road, and IH 35 

sites. Only low concentrations were measured in the samples 

collected from the catchment areas upstream from the Morey 

Road site. 

Patterns of PCB congener concentrations can indicate 

sources, and potential sources to the Leon Creek stream 

sediments were explored by comparing the relative 

distributions of congeners in the sediment samples (Colman, 

2000; Johnson and others, 2000; Cacela and others, 

2002). Samples with no detections of any PCB congeners 

were excluded; only 40 of the 49 samples remained for 

comparison. Congener proportions were computed by 

dividing the individual PCB congener concentrations by 

the sum of the detected PCB congeners. Examples of PCB 

congener patterns in the sample with the greatest number 

of congener detections collected at each site are provided 

in figure 13. PCB congeners 138 and 180 dominated the 

PCB mixtures. PCB congener 138 represented the greatest 

proportion of the PCB mixture in 35 percent, and PCB 

congener 180 represented the greatest proportion of the 

mixture in 50 percent of the samples collected from the 

Loop 410, Rodriguez Park, Highway 90, and Morey Road 

sites. PCB congener 138 constituted the greatest proportion 

of the PCB mixture in 13 percent, and PCB congener180 

Figure 12. Concentrations of total polychlorinated biphenyls 

in streambed- and suspended-sediment samples collected from 

Leon Creek, San Antonio, Texas, 2007–9 and 2012–14.

0

5

10

15

20

25

30

Total polychlorinated biphenyl (PCB) concentration,

in micrograms per kilogram (μg/kg) 

Loop 410

Rodriguez Park

Morey Road

Joint Base

Highway 90

Military Drive

Quintana Road

IH 35

Loop 410

Rodriguez Park

Morey Road

Joint Base

Highway 90

Military Drive

Quintana Road

IH 35

Site identifier (fig. 2)

Total PCB

[TEC 59.8 μg/kg, 

PEC 676 μg/kg] 

n/an/an/an/a

(77.0)

Low-flow

streambed

sediment

High-flow

suspended

sediment

EXPLANATION

Sediment sample collected from Leon Creek for total 

 PCB concentration—Samples collected 2007–9 

 are gray symbols. Samples collected 2012–14 are

 nongray symbols

 Detection

 Nondetection at interim reporting level

Concentration value off scale 

TEC, threshold effect concentration 

PEC, probable effect concentration 

n/a, not applicable because suspended-sediment

 samples were not collected 

(77.0)

constituted the greatest proportion of the PCB mixture in 80 

percent of the samples collected from the Joint Base, Military 

Drive, Quintana Road, and IH 35 sites. Five samples without 

a single dominant congener, such as the sample collected at 

Joint Base on December 3, 2007 (fig. 13), were not included in 

the previous summary statistics.
26 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Figure 13. Examples of polychlorinated biphenyl congener concentrations normalized to the sum of the detected congener 

concentrations in selected stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2007–9 and 2012–14.

49

52

70

101

110

118

138

146

149

151

170

174

177

180

183

187

194

206

49

52

70

101

110

118

138

146

149

151

170

174

177

180

183

187

194

206

PCB congener

Ratio of individual PCB congener to sum of PCB congeners

0

0.1

0.2

0.3

0

0.1

0.2

0.3

0

0.1

0.2

0.3

0

0.1

0.2

0.3

Rodriguez Park

Aug. 5, 2008

Loop 410

May 24, 2013

Highway 90

Nov. 29, 2007

Morey Road

May 24, 2013

Joint Base

Dec. 3, 2007

Military Drive

Dec. 3, 2007

Quintana Road

Nov. 29, 2007

IH 35

July 24, 2008

Highlight of dominant polychlorinated biphenyl (PCB)

 congener(s) in the mixture

PCB congener in sediment sample—Samples collected

 in 2007–8 are gray symbols. Samples collected in

 2013 are nongray symbols

 Streambed-sediment sample

 Suspended-sediment sample

EXPLANATION

IH, Interstate Highway
Potential Sources of Polychlorinated Biphenyls 27

Based on PCB congener patterns, there is a slight 

difference in the PCB mixtures in the samples collected 

upstream from the Joint Base compared to samples collected 

on and downstream from the base, which may be indicative 

of different PCB sources to the sites. The differences 

correspond to the increase in total PCBs at the Joint Base site 

compared to the sites upstream. Differences between PCB 

mixtures at the Leon Creek stream-sediment-sampling sites 

were evaluated statistically by computing the C2 test statistic 

(Haan, 1977) between the proportional PCB congener profiles 

of selected samples following the approach of Van Metre 

and Mahler (2014). The C2 is computed as the summation 

of the squared difference divided by the mean for each of 

the PCB congeners in a sample pair; the higher the C2, the 

more different the PCB mixtures (table 10).Nineteen of 49 

samples were eliminated from compared sample data because 

the PCB congener concentrations frequently were less than 

the IRLs. Congeners were eliminated from compared sample 

data if the concentration of a congener was less than the IRL 

in any sample, which resulted in the use of PCB congeners 

170, 180, 187, and 206. It is unfortunate that PCB congener 

138 was eliminated from the compared sample data because 

it was important when identifying differences in the congener 

patterns; however, the congener was not detected in 30 of the 

49 samples in the compared sample data, making it useless 

during computations of the C2 test statistic. The mean C2

test statistic was greatest (PCB mixtures different) between 

the samples collected from the Loop 410 and Military Drive 

sites (0.228 plus or minus [±] 0.13), Loop 410 and Quintana 

Road sites (0.210 ± 0.08), and Loop 410 and Joint Base sites 

(0.205 ± 0.08) (table 11). The mean C2 test statistic was 

lowest (PCB mixtures similar) between the samples collected 

from the Quintana Road and Military Drive sites (0.030 ± 

0.03), Joint Base and Quintana Road sites (0.034 ±0.04), and 

Highway 90 and Quintana Road sites (0.037± 0.02).
28 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 10. Chi-square (C2) test statistics between proportional polychlorinated biphenyl (PCB) congener profiles of stream-sediment 

samples collected from sites on Leon Creek, San Antonio, Texas, 2007–9 and 2012–14.

[SB, bottom material; SS, suspended sediment]

Site 

identifier 

(fig. 2)

Date

Site 

identifier

(fig. 2)

Loop 

410

Loop 

410

Rodriguez 

Park

Rodriguez 

Park

Rodriguez 

Park

Rodriguez 

Park

Rodriguez 

Park

Rodriguez 

Park

Rodriguez 

Park

Highway 

90

Date 5/24/2013 6/25/2013 11/29/2007 2/7/2013 5/14/2013 5/24/2013 6/24/2013 6/25/2014 8/5/2008 11/29/2007

Medium 

code SS SB SB SB SB SS SB SS SB SB

Loop 410 5/24/2013 SS 0.149 0.164 0.181 0.084 0.043 0.117 0.099 0.203 0.173

Loop 410 6/25/2013 SB 0.077 0.522 0.071 0.082 0.027 0.082 0.093 0.063

Rodriguez 

Park

11/29/2007 SB 0.374 0.020 0.063 0.021 0.011 0.017 0.008

Rodriguez 

Park

2/7/2013 SB 0.264 0.212 0.374 0.276 0.371 0.382

Rodriguez 

Park

5/14/2013 SB 0.013 0.013 0.003 0.028 0.019

Rodriguez 

Park

5/24/2013 SS 0.031 0.025 0.067 0.055

Rodriguez 

Park

6/24/2013 SB 0.019 0.027 0.012

Rodriguez 

Park

6/25/2014 SS 0.028 0.019

Rodriguez 

Park

8/5/2008 SB 0.004

Highway 

90

11/29/2007 SB

Highway 

90

8/12/2009 SB 

Morey 

Road

4/30/2013 SS 

Morey 

Road

5/24/2013 SS 

Morey 

Road

6/25/2013 SB 

Morey 

Road

6/25/2014 SS 

Joint Base 8/12/2009 SB 

Joint Base 2/6/2013 SB 

Joint Base 5/13/2013 SB 

Joint Base 6/24/2013 SB 

Joint Base 7/21/2014 SB 

Joint Base 12/3/2007 SB

Joint Base 8/5/2008 SB

Military 

Drive

12/3/2007 SB

Quintana 

Road

11/29/2007 SB

Quintana 

Road

8/13/2009 SB 

IH 35 12/11/2007 SB

IH 35 7/24/2008 SS

IH 35 8/6/2008 SB

IH 35 5/16/2009 SS 

IH 35 5/23/2009 SS 
Potential Sources of Polychlorinated Biphenyls 29

Table 10. Chi-square (C2) test statistics between proportional polychlorinated biphenyl (PCB) congener profiles of stream-sediment 

samples collected from sites on Leon Creek, San Antonio, Texas, 2007–9 and 2012–14.—Continued

[SB, bottom material; SS, suspended sediment]

Site 

identifier 

(fig. 2)

Date

Site 

identifier

(fig. 2)

Highway 

90

Morey 

Road

Morey 

Road

Morey 

Road

Morey 

Road

Joint 

Base

Joint 

Base

Joint 

Base

Joint 

Base

Joint 

Base

Date 8/12/2009 4/30/2013 5/24/2013 6/25/2013 6/25/2014 8/12/2009 2/6/2013 5/13/2013 6/24/2013 7/21/2014

Medium 

code SB SS SS SB SS SB SB SB SB SB 

Loop 410 5/24/2013 SS 0.125 0.114 0.059 0.021 0.056 0.101 0.241 0.264 0.275 0.249

Loop 410 6/25/2013 SB 0.136 0.224 0.097 0.078 0.104 0.230 0.196 0.160 0.118 0.137

Rodriguez 

Park

11/29/2007 SB 0.019 0.081 0.064 0.081 0.037 0.088 0.036 0.022 0.018 0.014

Rodriguez 

Park

2/7/2013 SB 0.255 0.205 0.200 0.223 0.215 0.118 0.311 0.393 0.473 0.404

Rodriguez 

Park

5/14/2013 SB 0.019 0.069 0.013 0.025 0.010 0.050 0.054 0.058 0.066 0.051

Rodriguez 

Park

5/24/2013 SS 0.050 0.092 0.002 0.006 0.018 0.056 0.105 0.119 0.131 0.111

Rodriguez 

Park

6/24/2013 SB 0.050 0.127 0.035 0.042 0.039 0.113 0.084 0.069 0.056 0.057

Rodriguez 

Park

6/25/2014 SS 0.008 0.053 0.026 0.037 0.009 0.046 0.043 0.044 0.053 0.038

Rodriguez 

Park

8/5/2008 SB 0.043 0.136 0.057 0.100 0.065 0.102 0.026 0.018 0.021 0.016

Highway 

90

11/29/2007 SB 0.038 0.123 0.051 0.080 0.051 0.104 0.040 0.026 0.021 0.019

Highway 

90

8/12/2009 SB 0.027 0.050 0.066 0.014 0.030 0.029 0.037 0.057 0.034

Morey 

Road

4/30/2013 SS 0.099 0.093 0.033 0.030 0.092 0.114 0.145 0.110

Morey 

Road

5/24/2013 SS 0.015 0.023 0.049 0.089 0.108 0.125 0.103

Morey 

Road

6/25/2013 SB 0.020 0.072 0.145 0.157 0.162 0.144

Morey 

Road

6/25/2014 SS 0.030 0.073 0.085 0.100 0.077

Joint Base 8/12/2009 SB 0.064 0.102 0.148 0.105

Joint Base 2/6/2013 SB 0.009 0.037 0.015

Joint Base 5/13/2013 SB 0.010 0.001

Joint Base 6/24/2013 SB 0.006

Joint Base 7/21/2014 SB 

Joint Base 12/3/2007 SB

Joint Base 8/5/2008 SB

Military 

Drive

12/3/2007 SB

Quintana 

Road

11/29/2007 SB

Quintana 

Road

8/13/2009 SB 

IH 35 12/11/2007 SB

IH 35 7/24/2008 SS

IH 35 8/6/2008 SB

IH 35 5/16/2009 SS 

IH 35 5/23/2009 SS 
30 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 10. Chi-square (C2) test statistics between proportional polychlorinated biphenyl (PCB) congener profiles of stream-sediment 

samples collected from sites on Leon Creek, San Antonio, Texas, 2007–9 and 2012–14.—Continued

[SB, bottom material; SS, suspended sediment]

Site 

identifier 

(fig. 2)

Date

Site 

identifier

(fig. 2)

Joint 

Base

Joint 

Base

Military 

Drive

Quintana 

Road

Quintana 

Road IH 35 IH 35 IH 35 IH 35 IH 35

Date 12/3/2007 8/5/2008 12/3/2007 11/29/2007 8/13/2009 12/11/2007 7/24/2008 8/6/2008 5/16/2009 5/23/2009

Medium 

code SB SB SB SB SB SB SS SB SS SS 

Loop 410 5/24/2013 SS 0.386 0.205 0.323 0.249 0.272 0.265 0.120 0.163 0.119 0.128

Loop 410 6/25/2013 SB 0.166 0.141 0.134 0.100 0.217 0.093 0.161 0.138 0.289 0.323

Rodriguez 

Park

11/29/2007 SB 0.067 0.012 0.035 0.014 0.038 0.021 0.032 0.015 0.123 0.151

Rodriguez 

Park

2/7/2013 SB 0.622 0.336 0.533 0.446 0.354 0.481 0.212 0.279 0.099 0.074

Rodriguez 

Park

5/14/2013 SB 0.146 0.034 0.095 0.050 0.075 0.061 0.022 0.020 0.083 0.101

Rodriguez 

Park

5/24/2013 SS 0.230 0.084 0.167 0.106 0.139 0.117 0.047 0.057 0.087 0.099

Rodriguez 

Park

6/24/2013 SB 0.120 0.052 0.077 0.040 0.105 0.042 0.063 0.046 0.159 0.185

Rodriguez 

Park

6/25/2014 SS 0.125 0.022 0.080 0.042 0.055 0.054 0.014 0.012 0.076 0.096

Rodriguez 

Park

8/5/2008 SB 0.078 0.017 0.036 0.009 0.045 0.013 0.049 0.019 0.145 0.165

Highway 

90

11/29/2007 SB 0.075 0.020 0.036 0.010 0.055 0.013 0.048 0.022 0.148 0.172

Highway 

90

8/12/2009 SB 0.129 0.015 0.085 0.052 0.031 0.069 0.003 0.007 0.049 0.068

Morey 

Road

4/30/2013 SS 0.226 0.076 0.183 0.146 0.083 0.171 0.027 0.059 0.028 0.045

Morey 

Road

5/24/2013 SS 0.227 0.076 0.161 0.099 0.127 0.111 0.043 0.050 0.081 0.091

Morey 

Road

6/25/2013 SB 0.260 0.114 0.201 0.138 0.175 0.150 0.065 0.084 0.102 0.116

Morey 

Road

6/25/2014 SS 0.185 0.050 0.135 0.087 0.086 0.103 0.016 0.031 0.051 0.068

Joint Base 8/12/2009 SB 0.251 0.067 0.189 0.135 0.080 0.160 0.015 0.042 0.005 0.010

Joint Base 2/6/2013 SB 0.101 0.007 0.057 0.033 0.007 0.047 0.028 0.009 0.089 0.105

Joint Base 5/13/2013 SB 0.053 0.005 0.022 0.011 0.009 0.019 0.045 0.016 0.134 0.157

Joint Base 6/24/2013 SB 0.023 0.019 0.004 0.003 0.034 0.004 0.074 0.037 0.188 0.218

Joint Base 7/21/2014 SB 0.045 0.005 0.016 0.006 0.014 0.013 0.045 0.016 0.139 0.164

Joint Base 12/3/2007 SB 0.075 0.009 0.036 0.084 0.030 0.156 0.106 0.294 0.331

Joint Base 8/5/2008 SB 0.037 0.017 0.009 0.028 0.021 0.004 0.095 0.117

Military 

Drive

12/3/2007 SB 0.009 0.050 0.007 0.106 0.061 0.232 0.264

Quintana 

Road

11/29/2007 SB 0.038 0.002 0.066 0.030 0.178 0.205

Quintana 

Road

8/13/2009 SB 0.053 0.036 0.018 0.100 0.121

IH 35 12/11/2007 SB 0.085 0.044 0.207 0.236

IH 35 7/24/2008 SS 0.009 0.031 0.046

IH 35 8/6/2008 SB 0.067 0.085

IH 35 5/16/2009 SS 0.004

IH 35 5/23/2009 SS 
Potential Sources of Polychlorinated Biphenyls 31

Table 11. Summary of mean and standard deviation (mean ± standard deviation) of Chi-square (C2) test statistics between proportional 

polychlorinated biphenyl (PCB) congener1 profiles of stream-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 

2007–9 and 2012–14.

[± , plus or minus; --, no data because single sample; greatest mean C2 test statistics highlighted in tan; lowest mean C2 test statistics highlighted in green]

Site identifier 

(fig. 2)

Loop 

410

Rodriguez 

Park

Highway 

90

Morey 

Road

Joint 

Base

Military 

Drive

Quintana 

Road IH 35

Site identifier 

(fig. 2)

Loop 

410

0.149

± 0.00

0.132

± 0.12

0.124

± 0.05

0.094

± 0.06

0.205

± 0.08

0.228

± 0.13

0.210

± 0.08

0.180

± 0.08

Rodriguez 

Park

0.107

± 0.14

0.067

± 0.11

0.074

± 0.07

0.110

± 0.13

0.146

± 0.18

0.108

± 0.13

0.095

± 0.09

Highway 

90

0.038

± 0.00

0.058

± 0.03

0.045

± 0.03

0.061

± 0.03

0.037

± 0.02

0.060

± 0.06

Morey 

Road

0.047

± 0.04

0.115

± 0.06

0.170

± 0.03

0.118

± 0.03

0.075

± 0.04

Joint 

Base

0.055

± 0.06

0.048

± 0.06

0.034

± 0.04

0.085

± 0.08

Military 

Drive

-- 0.030

± 0.03

0.134

± 0.11

Quintana 

Road

0.038

± 0.00

0.081

± 0.07

IH 35 0.081

± 0.08

1

PCB congeners 170, 180, 187, and 206.

Polychlorinated biphenyls were sold commercially as 

mixtures of congeners named Aroclors. Three of the most 

commonly produced and used Aroclors were 1242, 1254, and 

1260. The last two digits of the Aroclor number indicate the 

approximate chlorine content by weight percentage, which 

is relevant to their potential for environmental degradation 

(Agency for Toxic Substances and Disease Registry, 

2000). Aroclor 1242 was widely used, mostly in industrial 

applications such as transformers, hydraulic fluids, lubricants, 

and plasticizers. Aroclor 1254 was also widely used in the 

same industrial application as Aroclor 1242, plus several 

miscellaneous applications such as sealants, pesticides, 

cutting oils, and inks. Aroclor 1260 was commonly used 

in transformer fluids, hydraulic fluids, synthetic resins, and 

dedusting agents. On an overall basis, Aroclors 1242 and 

1254 were more widely used in manufacturing applications 

compared to Aroclor 1260 (International Agency for Research 

on Cancer, 1978). Despite its relatively limited use, Aroclor 

1260 was detected more frequently than Aroclors 1242 and 

1254 in fish samples collected in 2002 from three sites in 

the study area (Highway 90, Joint Base, and Military Drive; 

Texas Department of Health, 2003). Frame and others (1996) 

determined the PCB congener distributions of several Aroclor 

mixtures. The PCB congener mixtures in the stream-sediment 

samples collected from Leon Creek during 2007–9 and 

2012–14 were compared to Aroclors 1242, 1254, and 1260 

to identify similarities in the congener patterns (fig. 14). The 

PCB congener pattern in the Leon Creek samples is most like 

the congener mixture in Aroclor 1260, which is chemically 

similar to the PCBs detected in the fish samples that resulted 

in the 2003 fish consumption advisory. Nonetheless, the 

types of Aroclors used in different catchment areas are not 

known, and it remains unclear whether the similarity between 

Aroclors and sediment samples is related to historical use or 

environmental degradation of the lower chlorinated congeners.

The PCB congener mixtures were chemically distinct 

and significantly different based on the C2 test results for 

the samples collected from sites upstream from the Joint 

Base compared to the samples collected from sites on and 

downstream from the Joint Base. There were several data 

limitations that inhibited further exploration of the PCB 

sources to Leon Creek stream sediments in this study. First, 

there is little knowledge about the potential sources of PCBs 

in the Leon Creek catchment areas. Several potential PCB 

sources have been identified in the Leon Creek catchment 

areas (abandoned municipal landfills and industrial wastewater 

outfalls, for example); however, PCB mixtures from the 

potential sources have not been evaluated in a way that would 

facilitate linking PCBs at the sampling sites in this study to 

potential sources. Second, there are numerous nondetections in 

the Leon Creek stream-sediment laboratory results, and many 

of the IRLs are higher than the reported detections. Datasets 
32 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Figure 14. Comparison of polychlorinated biphenyl congeners in commercial Aroclor mixtures and selected streambed- and 

suspended-sediment samples collected from Leon Creek, San Antonio, Texas, 2007–8 and 2014.

0

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12

Concentration of PCB congener in Aroclor mixture, in micrograms per kilogram (μg/kg)

0

0.2

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Concentration of PCB congener in streambed- or suspended-sediment sample, in micrograms per kilogram (μg/kg)

49

52

70

101

110

118

138

146

149

151

170

174

177

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183

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194

206

49

52

70

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110

118

138

146

149

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170

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194

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49

52

70

101

110

118

138

146

149

151

170

174

177

180

183

187

194

206

PCB congener

Aroclor 1242 Aroclor 1254 Aroclor 1260

Polychlorinated biphenyl (PCB) congener in

 Aroclor mixture—Comparisons to samples

 collected 2007–8 are gray bars. Comparisons

 to samples collected 2013 are nongray bars

PCB congener in sediment

 sample

 Detection

 Nondetection

EXPLANATION

IH, Interstate Highway

Loop 410

 suspended

 sediment—

 Sample

 collected

 May 24, 2013

Rodriguez Park

 suspended

 sediment—

 Sample

 collected

 May 24, 2013

Highway 90

 streambed

 sediment—

 Sample

 collected

 Nov. 29, 2007

Military Drive

 streambed

 sediment—

 Sample

 collected

 Dec. 3, 2007

Quintana Road

 streambed

 sediment—

 Sample

 collected

 Nov. 29, 2007

IH 35

 streambed

 sediment—

 Sample

 collected

 Aug. 6, 2008

Morey Road

 suspended

 sediment—

 Sample

 collected

 May 24, 2013

Joint Base

 streambed

 sediment—

 Sample

 collected

 June 24, 2013
Summary 33

are typically censored at the highest IRL when performing 

statistical analyses with nondetections (Helsel, 2005), which 

essentially eliminated detections at concentrations less than 

the IRL leaving insufficient data for analysis. And finally, 

regardless of the nondetections in the stream-sediment 

sample results, the sample size is small (less than 100), 

which prohibits the use of multivariate statistics or principal 

component analyses. 

Summary

The U.S. Geological Survey (USGS), in cooperation 

with the San Antonio River Authority, collected streambedand suspended-sediment samples from Leon Creek during 

2012–14 to characterize selected contaminants in Leon 

Creek, San Antonio, Texas. Stream-sediment samples were 

collected from Leon Creek at northwest Interstate Highway 

410 (USGS station 08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.; hereinafter referred to as the “Loop 410 

site”), Rodriguez Park (USGS station 292443098364600 

Leon Creek at Rodriguez Park, San Antonio, Tex.; hereinafter 

referred to as the “Rodriguez Park site”), the northern 

boundary of the Joint Base San Antonio-Lackland (USGS 

station 292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.; hereinafter referred to as the “Morey 

Road site”), and on the southern part of the Joint Base San 

Antonio-Lackland (USGS 292240098353600 Leon Creek 

at Lackland Air Force Base Golf Course, San Antonio, Tex.; 

hereinafter referred to as the “Joint Base site”). The USGS 

periodically collected streambed-sediment samples during 

low flow and suspended-sediment samples during high flow. 

The samples were analyzed for major and trace elements and 

halogenated organic compounds (pesticides, flame retardants, 

and polychlorinated biphenyl [PCB] congeners). The degree 

of contamination of each sample was assessed by comparing 

concentrations to consensus-based sediment-quality guidelines 

(SQGs). The frequencies with which the halogenated organic 

compounds were detected in the stream-sediment samples 

were assessed, and comparisons of concentrations among site 

samples were made to describe the occurrence and distribution 

of the contaminants and potential sources of the PCBs.

Concentrations of the contaminants in the streamsediment samples were compared to consensus-based 

SQGs to determine the degree of contamination. Two SQG 

concentration levels were used: (1) a lower level, called 

the threshold effect concentration (TEC), and (2) a higher 

level, called the probable effect concentration (PEC). 

Adverse effects to benthic biota are not expected when the 

concentration is less than the TEC, whereas adverse effects 

to benthic biota are likely when the PEC is exceeded. No 

trace element concentrations were greater than the PEC in 

any of the samples. The concentrations of copper, lead, and 

mercury were less than the TEC in all of the samples. The 

percentage of samples with concentrations greater than the 

TEC for all eight trace elements was greatest at the Morey 

Road site (41 percent) followed by the Joint Base (27 percent), 

Rodriguez Park (18 percent), and Loop 410 (14 percent) sites.

Pesticides that have been banned for several 

decades are commonly detected in Leon Creek stream 

sediments, particularly the chlordane compounds. The 

chlordane compounds were detected in 84 percent of 

the samples and at every sample collection site. The 

samples collected from the Rodriguez Park site had 

the most pesticide compounds detected. None of the 

samples collected from the Loop 410, Rodriguez Park, 

or Morey Road sites had dichlorodiphenyldichloroethane 

(DDD), dichlorodiphenyldichloroethylene (DDE), or 

dichlorodiphenyltrichloroethane (DDT) concentrations 

greater than the TEC. Several of the samples collected from 

the Joint Base site had DDD, DDE, or DDT concentrations 

greater than the TEC, and a few were greater than the PEC. 

Whereas the frequent detections of pesticides in the Leon 

Creek stream sediments are notable, the few concentrations 

that exceed higher SQGs at the Joint Base site are of most 

concern. 

Flame retardants were found at every site on Leon 

Creek where stream sediments were collected; however, 

some compounds were frequently detected in the laboratory 

reagent blanks so their detections in the environmental 

samples may not be from local sources. Dechlorane plus 

and polybrominated diphenyl ether (PBDE) congener 153 

were the most frequently detected flame retardant compounds. 

The concentrations of flame retardants were greater in the 

suspended-sediment samples than the streambed-sediment 

samples and were greater than the Environment Canada 

SQG in many cases. Flame retardants in Leon Creek stream 

sediments are of moderate concern based on their frequent 

occurrence and concentrations in suspended sediments. 

Eighteen PCB congeners were quantified in the streamsediment samples. The samples collected from the Joint 

Base site had the most frequent PCB congener detections. 

Total PCB concentrations, computed as the sum of the 18 

congeners by using the Kaplan-Meier method for left-censored 

environmental data, were much smaller than the TEC of 

59.8 micrograms per kilograms (μg/kg). When detected, the 

concentrations of total PCBs in the stream-sediment samples 

collected from Leon Creek during 2012–14 ranged from 

an estimated 0.2 to 8.7 μg/kg. The results from the qualitycontrol samples indicated negative or low bias for the PCB 

congener concentrations, which may have resulted in slightly 

lower reported concentrations than actual environmental 

concentrations.

This report focused primarily on PCBs because the 

concentrations in Leon Creek were greater than other streams 

in Bexar County and fish consumption advisories in Leon 

Creek had been linked to PCBs. Sediment samples were 

collected from Leon Creek by the USGS during 2007–9 and 

2012–14 at eight sites following identical field and laboratory 

methods and were evaluated to determine if potential PCB 

sources could be identified. Total PCB concentrations in 

the sediment samples collected from the Loop 410 site 
34 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

downstream to the Morey Road site were less than the PCB 

reporting levels or low relative to total PCB concentrations 

measured in samples collected from sites farther downstream. 

PCB congeners 180 and 138 constituted the greatest proportion 

of the PCB mixture in samples collected upstream from, on, 

and downstream from the Joint Base site. Congeners 180 and 

138 constituted 50 percent and 35 percent, respectively, of the 

PCBs congeners found in the samples collected from the Loop 

410 site, Rodriguez Park site, USGS station 08181445 Leon 

Creek at State Highway 90, San Antonio, Tex. (hereinafter 

referred to as the “Highway 90 site”), and Morey Road 

site. Congeners 180 and 138 constituted 80 percent and 13 

percent, respectively, of the PCBs congeners found in the 

samples collected from the Joint Base site, USGS station 

292156098350900 Leon Creek at Southwest Military Drive, 

San Antonio, Tex. (hereinafter referred to as the “Military 

Drive site”), USGS station 292029098351400 Leon Creek at 

Quintana Road, San Antonio, Tex. (hereinafter referred to as 

the “Quintana Road site”), and USGS station 08181480 Leon 

Creek at Interstate Highway 35, San Antonio, Tex. (hereinafter 

referred to as the “IH 35 site”). Differences between PCB 

mixtures at the Leon Creek stream-sediment sampling sites 

were evaluated statistically by computing the Chi-square (C2) 

test statistic between the proportional PCB congener profiles of 

selected samples. The mean C2 test statistic was greatest (PCB 

mixtures different) between the samples collected from the 

Loop 410 and Military Drive (0.228 plus or minus [±] 0.13), 

Loop 410 and Quintana Road (0.210 ± 0.08), and Loop 410 

and Joint Base (0.205 ± 0.08). The mean C2 test statistic was 

lowest (PCB mixtures similar) between the samples collected 

from Quintana Road and Military Drive (0.030 ± 0.03), Joint 

Base and Quintana Road (0.034 ±0.04), and Highway 90 and 

Quintana Road (0.037± 0.02). The PCB congener mixtures in 

the stream-sediment samples collected from Leon Creek during 

2007–9 and 2012–14 were compared to Aroclors 1242, 1254, 

and 1260 to identify similarities in the congener patterns. The 

PCB congener pattern in the Leon Creek stream-sediment 

samples is most like the congener mixture in Aroclor 1260, 

which is chemically similar to the PCBs detected in the fish 

samples that resulted in the 2003 fish consumption advisory. 

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for ground- and surface-water samples, 1997–2001: U.S. 

Geological Survey Scientific Investigations Report 2005–

5225, 51 p.

Segev, Osnat, Kushmaro, Ariel, and Brenner, Asher, 2009, 

Environmental impact of flame retardants (persistence and 

biodegradability): International Journal of Environmental 

Research and Public Health, v. 6, no. 2, p. 478–491, 

accessed March 2, 2016, at http://www.ncbi.nlm.nih.gov/

pmc/articles/PMC2672362/.

Senesil, G.S., Baldassarre, G., Senesi, Nicola, Radina, B., 

1999, Trace element inputs into soils by anthropogenic 

activities and implications for human health: Chemosphere, 

v. 39, no. 2, p. 343–377.

Shelton, L.R., and Capel, P.D., 1994, Guidelines for collecting 

and processing samples of stream bed sediment for analysis 

of trace elements and organic contaminants for the National 

Water-Quality Assessment Program: U.S. Geological 

Survey Open File Report 94–458, 20 p.

Sinkkonen, Seija, and Paasivirta, Jaakko, 2000, Degradation 

half-life times of PCDDs, PCDFs and PCBs for 

environmental fate modeling: Chemosphere, v. 40, p. 943–

949.

Smith, J.A., Witkowski, P.J., and Fusillo, T.V., 1988, 

Manmade organic compounds in the surface water of the 

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Geological Survey Circular 1007, 92 p.

Texas Commission on Environmental Quality, 2009, Source 

water assessment: Accessed August 31, 2015, at: https://

www.tceq.texas.gov/drinkingwater/SWAP/index_swa.html.

Texas Commission on Environmental Quality, 2015, 2014 

Guidance for assessing and reporting surface water quality 

in Texas, in compliance with sections 305(b) and 303(d) 

of the Federal Clean Water Act: Surface Water Quality 

Monitoring Program, Monitoring and Assessment Section, 

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at https://www.tceq.texas.gov/assets/public/waterquality/

swqm/assess/14txir/2014_guidance.pdf.

Texas Department of Health, 2003, Quantitative risk 

characterization, lower Leon Creek, San Antonio, 

Bexar County, Texas: Austin, Seafood Safety Division, 

Environmental Epidemiology and Toxicology Division, 

21 p.
References Cited 37

Texas Department of State Health Services, 2010, 

Characterization of potential adverse health effects 

associated with consuming fish from lower Leon 

Creek, Bexar County, Texas: Austin, Texas, Division 

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Roundtable, EPA 542–B–00–005, 83 p.

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Tables 3, 6, and 8
40 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Station 

number

Station 

name

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Calcium

(milligrams 

per 

kilogram)

Magnesium

(milligrams 

per 

kilogram)

Potassium

(milligrams 

per 

kilogram)

Sodium

(milligrams 

per 

kilogram)

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SB 210,000 5,840 9,600 820

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SBQ 

(replicate)

200,000 5,730 9,300 780

RPD of replicate sample concentrations: 5 2 3 5

292240098353600 Leon Creek at Lackland 

Air Force Base Golf 

Course,San Antonio,Tex.

Joint Base 11/16/2012 SB 116,000 7,290 11,300 3,340

292240098353600 Leon Creek at Lackland 

Air Force Base Golf 

Course,San Antonio,Tex.

Joint Base 11/16/2012 SBQ 

(replicate)

116,000 7,150 11,200 3,350

RPD of replicate sample concentrations: 0 2 1 0

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 5/14/2013 SB 190,000 5,970 8,800 800

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 5/14/2013 SBQ 

(replicate)

200,000 5,900 8,600 770

RPD of replicate sample concentrations: 5 1 2 4

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 2/7/2013 SB 208,000 5,830 8,800 760

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 2/7/2013 SBQ 

(replicate)

202,000 5,790 8,600 740

RPD of replicate sample concentrations: 3 1 2 3

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

2/6/2013 SB 163,000 6,290 10,000 2,150

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

2/6/2013 SBQ 

(replicate)

159,000 6,140 9,800 2,140

RPD of replicate sample concentrations: 2 2 2 0

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

6/25/2013 SB 158,000 6,540 10,600 2,140

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

6/25/2013 SBQ 

(replicate)

141,000 6,050 10,000 2,080

RPD of replicate sample concentrations: 11 8 6 3

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 7/22/2014 SB 214,000 6,260 9,300 830

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 7/22/2014 SBQ 

(replicate)

212,000 6,290 8,900 770

RPD of replicate sample concentrations: 1 0 4 8

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

5/24/2013 SS 14,700 600 1,000 4,200

292338098360501 Leon Creek at Morey 

Road, San Antonio, Tex.

Morey 

Road

5/24/2013 SSQ 

(replicate)

13,100 600 1,100 4,700

RPD of replicate sample concentrations: 12 0 10 11

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

4/30/2013 SS 14,800 580 1,000 700

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

14,700 560 960 800

RPD of replicate sample concentrations: 1 4 4 13

Table 3
Table 3 41

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Carbon 

(inorganic 

plus 

organic)

(percent)

Inorganic 

carbon

(percent)

Phosphorus

(milligrams 

per 

kilogram)

Aluminum

(milligrams 

per 

kilogram)

Barium

(milligrams 

per 

kilogram)

Beryllium

(milligrams 

per 

kilogram)

Bismuth

(milligrams 

per 

kilogram)

Cadmium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB -- 5.9 590 37,000 150 0.92 0.15 0.3

Loop 410 11/15/2012 SBQ 

(replicate)

-- 5.8 560 37,000 150 0.95 0.15 0.3

RPD of replicate sample 

concentrations:

-- 2 5 0 0 3 0 0

Joint Base 11/16/2012 SB 5.0 3.1 790 50,000 260 1.3 0.27 0.6

Joint Base 11/16/2012 SBQ 

(replicate)

4.8 3.2 780 50,000 270 1.1 0.27 0.5

RPD of replicate sample 

concentrations:

4 3 1 0 4 17 0 18

Loop 410 5/14/2013 SB 6.8 5.9 600 36,000 140 0.83 0.16 0.3

Loop 410 5/14/2013 SBQ 

(replicate)

6.8 6.0 610 35,000 140 0.76 0.17 0.3

RPD of replicate sample 

concentrations:

0 2 2 3 0 9 6 0

Loop 410 2/7/2013 SB 6.9 6.0 590 36,000 150 0.84 0.15 0.3

Loop 410 2/7/2013 SBQ 

(replicate)

6.8 6.1 570 36,000 150 0.74 0.15 0.3

RPD of replicate sample 

concentrations:

1 2 3 0 0 13 0 0

Morey 

Road

2/6/2013 SB 6.3 4.7 940 43,000 190 1.1 0.21 0.3

Morey 

Road

2/6/2013 SBQ 

(replicate)

6.2 4.6 910 44,000 190 1.1 0.21 0.3

RPD of replicate sample 

concentrations:

2 2 3 2 0 0 0 0

Morey 

Road

6/25/2013 SB 6.0 4.6 1,000 38,000 230 1.3 0.18 0.3

Morey 

Road

6/25/2013 SBQ 

(replicate)

6.0 4.5 980 34,000 220 1.3 0.17 0.3

RPD of replicate sample 

concentrations:

0 2 2 11 4 0 6 0

Loop 410 7/22/2014 SB 7.2 6.5 620 33,000 140 0.94 0.13 0.3

Loop 410 7/22/2014 SBQ 

(replicate)

7.4 6.6 610 31,000 140 0.98 0.13 0.3

RPD of replicate sample 

concentrations:

3 2 2 6 0 4 0 0

Morey 

Road

5/24/2013 SS 5.8 4.4 810 38,000 220 1.2 0.2 0.2

Morey 

Road

5/24/2013 SSQ 

(replicate)

5.5 3.8 810 42,000 230 1.2 0.2 0.2

RPD of replicate sample 

concentrations:

5 15 0 10 4 0 0 0

Rodriguez 

Park

4/30/2013 SS 7.5 4.5 1,020 49,000 200 1.4 0.30 0.4

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

7.7 4.6 1,030 47,000 200 1.3 0.25 0.4

RPD of replicate sample 

concentrations:

3 2 1 4 0 7 18 0
42 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Cesium

(milligrams 

per 

kilogram)

Chromium

(milligrams 

per 

kilogram)

Cobalt

(milligrams 

per 

kilogram)

Copper

(milligrams 

per 

kilogram)

Gallium

(milligrams 

per 

kilogram)

Iron

(milligrams 

per 

kilogram)

Lead

(milligrams 

per 

kilogram)

Lithium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 5.40 42 4 11 8 14,000 9 28

Loop 410 11/15/2012 SBQ 

(replicate)

5.40 40 4 12 8 13,000 10 27

RPD of replicate sample 

concentrations:

0 5 0 9 0 7 11 4

Joint Base 11/16/2012 SB 4.80 55 6 20 11 24,000 28 27

Joint Base 11/16/2012 SBQ 

(replicate)

4.90 58 6 20 11 24,000 28 27

RPD of replicate sample 

concentrations:

2 5 0 0 0 0 0 0

Loop 410 5/14/2013 SB 5.20 38 4 11 8 14,000 10 22

Loop 410 5/14/2013 SBQ 

(replicate)

5.10 37 4 11 8 14,000 11 21

RPD of replicate sample 

concentrations:

2 3 0 0 0 0 10 5

Loop 410 2/7/2013 SB 4.80 35 4 12 8 14,000 11 19

Loop 410 2/7/2013 SBQ 

(replicate)

4.80 34 4 12 8 14,000 11 16

RPD of replicate sample 

concentrations:

0 3 0 0 0 0 0 17

Morey 

Road

2/6/2013 SB 4.50 43 7 15 10 22,000 17 18

Morey 

Road

2/6/2013 SBQ 

(replicate)

4.50 41 7 14 9 22,000 17 17

RPD of replicate sample 

concentrations:

0 5 0 7 11 0 0 6

Morey 

Road

6/25/2013 SB 4.90 42 9 15 10 22,000 17 26

Morey 

Road

6/25/2013 SBQ 

(replicate)

4.70 41 9 15 10 22,000 16 28

RPD of replicate sample 

concentrations:

4 2 0 0 0 0 6 7

Loop 410 7/22/2014 SB 5.00 42 3 12 8 12,000 15 26

Loop 410 7/22/2014 SBQ 

(replicate)

4.80 40 3 9 7 12,000 9 28

RPD of replicate sample 

concentrations:

4 5 0 29 13 0 50 7

Morey 

Road

5/24/2013 SS -- 38 6 15 9 17,000 19 25

Morey 

Road

5/24/2013 SSQ 

(replicate)

-- 39 6 16 10 18,000 19 26

RPD of replicate sample 

concentrations:

-- 3 0 6 11 6 0 4

Rodriguez 

Park

4/30/2013 SS -- 37 10 24 12 22,000 20 23

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

-- 34 10 16 10 21,000 21 22

RPD of replicate sample 

concentrations:

-- 8 0 40 18 5 5 4
Table 3 43

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Manganese

(milligrams 

per 

kilogram)

Mercury

(milligrams 

per 

kilogram)

Molybdenum

(milligrams 

per 

kilogram)

Nickel

(milligrams 

per 

kilogram)

Niobium

(milligrams 

per 

kilogram)

Rubidium

(milligrams 

per 

kilogram)

Scandium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 210 0.02 1.2 18 8 53.1 5

Loop 410 11/15/2012 SBQ 

(replicate)

210 0.02 1.1 17 8 51.2 5

RPD of replicate sample 

concentrations:

0 0 9 6 0 4 0

Joint Base 11/16/2012 SB 310 0.03 0.7 20 10 65.4 7

Joint Base 11/16/2012 SBQ 

(replicate)

310 0.05 0.7 19 10 65.3 7

RPD of replicate sample 

concentrations:

0 50 0 5 0 0 0

Loop 410 5/14/2013 SB 250 0.01 1.1 7 7 50.7 5

Loop 410 5/14/2013 SBQ 

(replicate)

260 0.01 1.0 5 7 49.6 5

RPD of replicate sample 

concentrations:

4 0 10 33 0 2 0

Loop 410 2/7/2013 SB 250 0.01 1.0 5 7 48.4 5

Loop 410 2/7/2013 SBQ 

(replicate)

250 0.01 1.0 5 7 47.1 5

RPD of replicate sample 

concentrations:

0 0 0 0 0 3 0

Morey 

Road

2/6/2013 SB 1,280 0.02 0.7 12 7 57.2 6

Morey 

Road

2/6/2013 SBQ 

(replicate)

1,250 0.02 0.7 12 7 56.5 6

RPD of replicate sample 

concentrations:

2 0 0 0 0 1 0

Morey 

Road

6/25/2013 SB 1,590 0.01 0.7 13 7 63.1 7

Morey 

Road

6/25/2013 SBQ 

(replicate)

1,740 0.01 0.7 13 6 59.4 6

RPD of replicate sample 

concentrations:

9 0 0 0 15 6 15

Loop 410 7/22/2014 SB 200 0.01 1.2 7 6 47.0 5

Loop 410 7/22/2014 SBQ 

(replicate)

190 0.01 1.2 5 6 46.0 4

RPD of replicate sample 

concentrations:

5 0 0 33 0 2 22

Morey 

Road

5/24/2013 SS 360 0.01 0.7 10 7 -- 6

Morey 

Road

5/24/2013 SSQ 

(replicate)

340 0.02 0.7 11 7 -- 6

RPD of replicate sample 

concentrations:

6 67 0 10 0 -- 0

Rodriguez 

Park

4/30/2013 SS 1,080 0.03 1.2 17 9 -- 7

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

1,350 0.04 0.8 17 8 -- 7

RPD of replicate sample 

concentrations:

22 29 40 0 12 -- 0
44 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Silver

(milligrams 

per 

kilogram)

Strontium

(milligrams 

per 

kilogram)

Thallium

(milligrams 

per 

kilogram)

Titanium

(milligrams 

per 

kilogram)

Vanadium

(milligrams 

per 

kilogram)

Zinc

(milligrams 

per 

kilogram)

Antimony

(milligrams 

per 

kilogram)

Arsenic

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 0.1 380 0.39 1,900 60 61 0.7 5.3

Loop 410 11/15/2012 SBQ 

(replicate)

0.1 370 0.35 1,780 57 57 0.7 5.2

RPD of replicate sample 

concentrations:

0 3 11 7 5 7 0 2

Joint Base 11/16/2012 SB 0.3 150 0.44 2,600 77 99 0.9 6.2

Joint Base 11/16/2012 SBQ 

(replicate)

0.3 150 0.45 2,600 76 98 0.9 6.1

RPD of replicate sample 

concentrations:

0 0 2 0 1 1 0 2

Loop 410 5/14/2013 SB 0.2 330 0.36 1,700 56 58 0.7 5.4

Loop 410 5/14/2013 SBQ 

(replicate)

0.2 340 0.36 1,700 56 58 0.6 5.8

RPD of replicate sample 

concentrations:

0 3 0 0 0 0 15 7

Loop 410 2/7/2013 SB 0.2 310 0.34 1,700 53 58 0.6 5.0

Loop 410 2/7/2013 SBQ 

(replicate)

0.2 320 0.36 1,600 52 55 0.6 4.8

RPD of replicate sample 

concentrations:

0 3 6 6 2 5 0 4

Morey 

Road

2/6/2013 SB 0.2 160 0.45 2,000 63 73 0.6 7.4

Morey 

Road

2/6/2013 SBQ 

(replicate)

0.2 160 0.43 2,000 61 71 0.6 7.3

RPD of replicate sample 

concentrations:

0 0 5 0 3 3 0 1

Morey 

Road

6/25/2013 SB 0.1 170 0.44 2,000 66 81 0.6 12.1

Morey 

Road

6/25/2013 SBQ 

(replicate)

0.1 160 0.45 1,700 61 79 0.5 12.9

RPD of replicate sample 

concentrations:

0 6 2 16 8 3 18 6

Loop 410 7/22/2014 SB <0.02 430 0.31 1,600 61 155 0.6 5.2

Loop 410 7/22/2014 SBQ 

(replicate)

<0.02 440 0.32 1,600 58 56 0.5 5.2

RPD of replicate sample 

concentrations:

-- 2 3 0 5 94 18 0

Morey 

Road

5/24/2013 SS <0.01 180 0.40 201 61 72 0.7 6.4

Morey 

Road

5/24/2013 SSQ 

(replicate)

<0.01 180 0.42 215 66 72 0.6 6.5

RPD of replicate sample 

concentrations:

-- 0 5 7 8 0 15 2

Rodriguez 

Park

4/30/2013 SS <1 180 0.5 190 54 92 1.0 11

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

<1 180 0.5 180 52 81 1.0 10

RPD of replicate sample 

concentrations:

-- 0 0 5 4 13 0 10
Table 3 45

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

alphaEndosulfan

(micrograms 

per 

kilogram)

Benfluralin

(micrograms 

per 

kilogram)

betaEndosulfan

(micrograms 

per 

kilogram)

Chlorpyrifos

(micrograms 

per 

kilogram)

cisChlordane

(micrograms 

per 

kilogram)

cisNonachlor

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.20 <0.20 <0.20 <0.20 <0.20 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 <0.20 <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.20 <0.20 <0.20 <0.20 1.18 0.37

Joint Base 11/16/2012 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 0.57 0.17

RPD of replicate sample 

concentrations:

-- -- -- -- 70 74

Loop 410 5/14/2013 SB <0.20 <0.20 <0.20 <0.20 0.06 <0.10

Loop 410 5/14/2013 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 E0.08 E0.04

RPD of replicate sample 

concentrations:

-- -- -- -- 29 --

Loop 410 2/7/2013 SB <0.20 <0.20 <0.20 <0.20 <0.20 <0.10

Loop 410 2/7/2013 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 0.01 <0.10

RPD of replicate sample 

concentrations:

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

Morey Road 2/6/2013 SB <0.20 <0.20 <0.20 <0.20 0.03 0.01

Morey Road 2/6/2013 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 0.05 E0.02

RPD of replicate sample 

concentrations:

-- -- -- -- 46 67

Morey Road 6/25/2013 SB <0.20 <0.20 <0.20 <0.20 0.27 E0.21

Morey Road 6/25/2013 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 0.08 E0.04

RPD of replicate sample 

concentrations:

-- -- -- -- 109 136

Loop 410 7/22/2014 SB <0.20 <0.20 <0.20 <0.20 <0.2 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 <0.2 <0.10

RPD of replicate sample 

concentrations:

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

Morey Road 5/24/2013 SS <0.20 <0.20 <0.20 E2.25 E0.69 E0.30

Morey Road 5/24/2013 SSQ 

(replicate)

<0.20 <0.20 <0.20 E1.30 0.75 E0.30

RPD of replicate sample 

concentrations:

-- -- -- 54 8 0

Rodriguez 

Park

4/30/2013 SS <0.20 <0.20 <0.20 <0.20 0.44 E0.09

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

<0.20 <0.20 <0.20 <0.20 0.60 E0.12

RPD of replicate sample 

concentrations:

-- -- -- -- 31 29
46 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Cyfluthrin

(micrograms 

per 

kilogram

DCPA 

(Dacthal)

(micrograms per 

kilogram

Desulfinylfipronil

(micrograms per 

kilogram)

Dieldrin

(micrograms 

per 

kilogram)

Endosulfan 

sulfate

(micrograms per 

kilogram)

Fipronil 

sulfide

(micrograms per 

kilogram)

Fipronil

(micrograms 

per 

kilogram)

Hexachlorobenzene

(micrograms per 

kilogram)

Loop 410 11/15/2012 SB <0.20 <0.2 0.1 <0.10 <0.4 <0.10 -- <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.20 <0.2 <0.10 <0.10 <0.4 <0.10 -- <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.60 <0.2 0.11 0.13 <0.4 <0.10 -- <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.20 <0.2 <0.10 <0.10 <0.4 <0.10 -- <0.10

RPD of replicate sample 

concentrations:

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

Loop 410 5/14/2013 SB E0.07 <0.2 E0.02 <0.10 <0.4 E0.02 -- <0.10

Loop 410 5/14/2013 SBQ 

(replicate)

E2.93 <0.2 E0.95 <0.10 <0.4 E0.05 -- <0.10

RPD of replicate sample 

concentrations:

191 -- 192 -- -- 86 -- --

Loop 410 2/7/2013 SB <0.20 <0.2 E0.01 <0.10 <0.4 <0.10 -- <0.10

Loop 410 2/7/2013 SBQ 

(replicate)

<0.20 <0.2 <0.10 <0.10 <0.4 <0.10 -- <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

2/6/2013 SB <0.20 <0.2 <0.10 <0.10 <0.4 <0.10 -- <0.10

Morey 

Road

2/6/2013 SBQ 

(replicate)

<0.20 <0.2 <0.10 <0.10 <0.4 <0.10 -- <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

6/25/2013 SB E2.00 <0.2 <0.10 E0.01 <0.4 E0.01 -- <0.10

Morey 

Road

6/25/2013 SBQ 

(replicate)

<2.00 <0.2 E0.07 E0.01 <0.4 E0.01 -- <0.10

RPD of replicate sample 

concentrations:

-- -- -- 0 -- 0 -- --

Loop 410 7/22/2014 SB <0.20 <0.2 <0.10 <0.10 <0.4 <0.10 <0.10 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.20 <0.2 <0.10 <0.10 <0.4 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

5/24/2013 SS E12.7 <0.2 <0.34 E0.28 <0.4 <0.10 -- <0.10

Morey 

Road

5/24/2013 SSQ 

(replicate)

E11.9 <0.2 E0.62 E0.46 <0.4 E0.14 E6.89 <0.10

RPD of replicate sample 

concentrations:

7 -- -- 49 -- -- -- --

Rodriguez 

Park

4/30/2013 SS E13.4 <0.2 E0.08 <0.10 <0.4 E0.05 -- <0.10

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

E11.9 <0.2 E0.07 <0.10 <0.4 E0.04 -- <0.10

RPD of replicate sample 

concentrations:

12 -- 13 -- -- 22 -- --
Table 3 47

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

lambdaCyhalothrin

(micrograms 

per kilogram)

Oxychlordane

(micrograms 

per 

kilogram)

Oxyfluorfen

(micrograms 

per 

kilogram)

p,p'-

DDD

(micrograms 

per 

kilogram)

p,p'-

DDE

(micrograms 

per 

kilogram)

p,p'-

DDT

(micrograms 

per kilogram)

Pendimethalin

(micrograms 

per 

kilogram)

Pentachloroanisole

(micrograms 

per 

kilogram)

Pentachloronitrobenzene

(micrograms per 

kilogram)

Loop 410 11/15/2012 SB <0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

1.7 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.20 <1.0 <4.0 9.6 13.7 <4.0 <1.0 <0.10 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.20 <1.0 <4.0 6.2 5.8 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- -- 43 81 -- -- -- --

Loop 410 5/14/2013 SB <0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

Loop 410 5/14/2013 SBQ 

(replicate)

<0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 0.01 <0.10

RPD of replicate sample 

concentrations:

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

Loop 410 2/7/2013 SB <0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

Loop 410 2/7/2013 SBQ 

(replicate)

<0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

2/6/2013 SB <0.20 <1.0 <4.0 <2.0 2.2 <4.0 <1.0 <0.10 <0.10

Morey 

Road

2/6/2013 SBQ 

(replicate)

<0.20 <1.0 <4.0 <2.0 1.2 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- -- -- 59 -- -- -- --

Morey 

Road

6/25/2013 SB <0.20 <1.0 <4.0 <2.0 E0.1 E1.5 <1.0 <0.10 <0.10

Morey 

Road

6/25/2013 SBQ 

(replicate)

<0.20 <1.0 <4.0 <2.0 E0.3 E4.7 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- -- -- 100 103 -- -- --

Loop 410 7/22/2014 SB <0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.20 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

5/24/2013 SS E3.23 <1.0 <4.0 <2.0 E0.3 <4.0 <1.0 0.03 <0.10

Morey 

Road

5/24/2013 SSQ 

(replicate)

E3.39 <1.0 <4.0 <2.0 E0.2 E3.6 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

5 -- -- -- 40 -- -- -- --

Rodriguez 

Park

4/30/2013 SS E2.09 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

E2.59 <1.0 <4.0 <2.0 <1.0 <4.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

21 -- -- -- -- -- -- -- --
48 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Tefluthrin

(micrograms 

per 

kilogram)

Tetradifon

(micrograms 

per 

kilogram)

transChlordane

(micrograms 

per kilogram)

transNonachlor

(micrograms 

per kilogram)

Trifluralin

(micrograms 

per kilogram)

PCB 

congener 

101

(micrograms 

per kilogram)

PCB 

congener 

110

(micrograms 

per kilogram)

PCB 

congener 

118

(micrograms 

per kilogram)

PCB 

congener 

138

(micrograms 

per kilogram)

Loop 410 11/15/2012 SB <0.50 <0.20 <0.20 <0.10 <0.20 <1.0 <1.0 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.50 <0.20 <0.20 <0.10 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.50 <0.20 0.76 0.86 <0.20 <1.0 <1.0 E0.18 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.50 <0.20 0.38 0.41 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- 67 71 -- -- -- -- --

Loop 410 5/14/2013 SB <0.50 <0.20 <0.20 E0.004 <0.20 <1.0 <1.0 <0.10 <0.10

Loop 410 5/14/2013 SBQ 

(replicate)

<0.50 <0.20 E0.03 E0.11 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- -- 186 -- -- -- -- --

Loop 410 2/7/2013 SB <0.50 <0.20 <0.20 <0.10 <0.20 <1.0 <1.0 <0.10 <0.10

Loop 410 2/7/2013 SBQ 

(replicate)

<0.50 <0.20 <0.20 <0.10 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

2/6/2013 SB <0.50 <0.20 0.02 0.02 <0.20 <1.0 <1.0 <0.10 <0.10

Morey 

Road

2/6/2013 SBQ 

(replicate)

<0.50 <0.20 E0.04 E0.05 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- 67 86 -- -- -- -- --

Morey 

Road

6/25/2013 SB <0.50 -- 0.18 E0.34 <0.20 <1.0 <1.0 <0.10 E0.0278

Morey 

Road

6/25/2013 SBQ 

(replicate)

<0.50 <0.20 0.05 E0.09 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- 113 116 -- -- -- -- --

Loop 410 7/22/2014 SB E0.04 <0.20 E0.10 E0.10 <0.20 <1.0 <1.0 <0.10 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.50 <0.20 <0.20 <0.10 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

5/24/2013 SS <0.50 -- E0.46 E0.71 <0.20 <1.0 <1.0 <0.10 0.15

Morey 

Road

5/24/2013 SSQ 

(replicate)

<0.50 <0.20 0.47 E0.70 <0.20 E0.12 E0.7 <0.10 E0.17

RPD of replicate sample 

concentrations:

-- -- 2 1 -- -- -- -- 13

Rodriguez 

Park

4/30/2013 SS <0.50 <0.20 E0.39 E0.36 <0.20 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

<0.50 <0.20 E0.53 E0.53 <0.20 <1.0 <1.0 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- 30 38 -- -- -- -- --
Table 3 49

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 

146

(micrograms 

per kilogram)

PCB 

congener 

149

(micrograms 

per kilogram)

PCB 

congener 

151

(micrograms 

per kilogram)

PCB 

congener 

170

(micrograms 

per kilogram)

PCB 

congener 

174

(micrograms 

per kilogram)

PCB 

congener 

177

(micrograms 

per kilogram)

PCB 

congener 

180

(micrograms 

per kilogram)

PCB 

congener 

183

(micrograms 

per kilogram)

PCB 

congener 

187

(micrograms 

per kilogram)

Loop 410 11/15/2012 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.10 <1.0 E0.14 E0.62 <0.10 <0.10 E0.96 E0.18 E0.41

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <1.0 <0.10 E0.30 <0.10 <0.10 E0.44 <0.10 E0.19

RPD of replicate sample 

concentrations:

-- -- -- 70 -- -- 74 -- 73

Loop 410 5/14/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

Loop 410 5/14/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 0.03 <0.10 <0.10 0.02 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Loop 410 2/7/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

Loop 410 2/7/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

2/6/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 0.01 <0.10 <0.10

Morey 

Road

2/6/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 0.02 <0.10 <0.10 0.02 <0.10 0.01

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- 67 -- --

Morey 

Road

6/25/2013 SB 0.01 <1.0 <0.10 0.01 <0.10 0.01 0.01 0.01 0.01

Morey 

Road

6/25/2013 SBQ 

(replicate)

0.01 <1.0 <0.10 0.01 0.02 0.01 0.02 0.01 0.01

RPD of replicate sample 

concentrations:

0 -- -- 0 -- 0 67 0 0

Loop 410 7/22/2014 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

5/24/2013 SS 0.04 0.1 0.05 0.06 0.08 0.06 0.09 0.04 0.07

Morey 

Road

5/24/2013 SSQ 

(replicate)

0.03 E0.1 0.05 0.07 0.08 0.06 0.08 0.05 0.06

RPD of replicate sample 

concentrations:

3 0 0 15 0 0 12 22 15

Rodriguez 

Park

4/30/2013 SS <0.10 <1.0 <0.10 <0.10 <0.10 <0.10 0.08 <0.10 <0.10

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10 0.08 <0.10 <0.10

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- 0 -- --
50 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 

194

(micrograms 

per kilogram)

PCB 

congener 

206

(micrograms 

per kilogram)

PCB 

congener 

49

(micrograms 

per kilogram)

PCB 

congener 

52

(micrograms 

per kilogram)

PCB 

congener 

70

(micrograms 

per kilogram)

1,2-Bis(2,4,6-

tribromophenoxy)

ethane

(micrograms per 

kilogram)

PBDE 

congener 

100

(micrograms per 

kilogram)

PBDE 

congener 

138

(micrograms per 

kilogram)

PBDE 

congener 

153

(micrograms per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.20 <0.10 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Loop 410 5/14/2013 SB <0.10 <0.10 <2.0 <1.0 <2.0 E0.22 E0.09 <0.10 E0.06

Loop 410 5/14/2013 SBQ 

(replicate)

<0.10 <0.10 <2.0 <1.0 <2.0 E0.094 <0.20 <0.10 E0.07

RPD of replicate sample 

concentrations:

-- -- -- -- -- 80 -- -- 15

Loop 410 2/7/2013 SB <0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 0.05

Loop 410 2/7/2013 SBQ 

(replicate)

<0.10 <0.10 <2.0 <1.0 <2.0 E0.15 E0.08 <0.10 E0.08

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- -- -- 46

Morey 

Road

2/6/2013 SB <0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 <0.10

Morey 

Road

2/6/2013 SBQ 

(replicate)

0.01 0.01 <2.0 <1.0 <2.0 E0.05 E0.08 <0.10 E0.05

RPD of replicate sample 

concentrations:

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

Morey 

Road

6/25/2013 SB 0.01 0.01 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 E0.03

Morey 

Road

6/25/2013 SBQ 

(replicate)

0.01 0.01 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 E0.03

RPD of replicate sample 

concentrations:

0 0 -- -- -- -- -- -- 0

Loop 410 7/22/2014 SB <0.10 <0.10 <2.0 <1.0 <2.0 <0.10 0.13 <0.10 <0.10

Loop 410 7/22/2014 SBQ 

(replicate)

<0.10 <0.10 <2.0 <1.0 <2.0 <0.10 <0.10 <0.10 <0.10

RPD of replicate sample 

concentrations:

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

Morey 

Road

5/24/2013 SS 0.04 0.04 <2.0 <1.0 <2.0 E2.10 E0.37 <0.10 E0.25

Morey 

Road

5/24/2013 SSQ 

(replicate)

0.03 0.04 <2.0 <1.0 <2.0 <0.20 E0.52 <0.10 E0.38

RPD of replicate sample 

concentrations:

29 0 -- -- -- -- 34 -- 41

Rodriguez 

Park

4/30/2013 SS 0.06 <0.10 <2.0 <1.0 <2.0 E0.74 E0.49 <0.10 E0.56

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

0.05 <0.10 <2.0 <1.0 <2.0 E0.43 E0.43 <0.10 E0.51

RPD of replicate sample 

concentrations:

18 -- -- -- -- 53 13 -- 9
Table 3 51

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PBDE 

congener 

154

(micrograms 

per kilogram)

PBDE 

congener 

183

(micrograms 

per kilogram)

PBDE 

congener 

47

(micrograms 

per kilogram)

PBDE 

congener 

66

(micrograms 

per kilogram)

PBDE 

congener 

71

(micrograms 

per kilogram)

PBDE 

congener 

85

(micrograms 

per kilogram)

PBDE 

congener 

99

(micrograms 

per kilogram)

Bis(hexachlorocyclopentadieno) 

cyclooctane

(micrograms 

per 

kilogram)

Methyl 

triclosan

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.10 <0.90 <0.10 <0.10 <0.10 <0.40 <1.0 <6.0

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.10 <0.90 <0.10 <0.10 <0.10 <0.30 <1.0 <6.0

RPD of replicate sample 

concentrations:

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

Joint Base 11/16/2012 SB <0.10 <0.10 <1.00 <0.10 <0.10 <0.10 <0.70 0.7 <6.0

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <0.10 <1.00 <0.10 <0.10 <0.10 <0.50 <1.0 <6.0

RPD of replicate sample 

concentrations:

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

Loop 410 5/14/2013 SB E0.03 <0.10 E0.64 <0.10 <0.10 E0.0065 E0.46 E0.4 <6.0

Loop 410 5/14/2013 SBQ 

(replicate)

E0.04 <0.50 <0.80 <0.10 <0.10 <0.10 <0.60 E0.1 <6.0

RPD of replicate sample 

concentrations:

29 -- -- -- -- -- -- 120 --

Loop 410 2/7/2013 SB 0.02 <0.10 <0.70 <0.10 <0.10 <0.10 <0.40 <1.0 <6.0

Loop 410 2/7/2013 SBQ 

(replicate)

E0.04 <0.10 E0.57 <0.10 <0.10 E0.013 E0.53 <1.0 <6.0

RPD of replicate sample 

concentrations:

67 -- -- -- -- -- -- -- --

Morey 

Road

2/6/2013 SB <0.10 <0.10 <0.20 <0.10 <0.10 <0.10 <0.20 0.1 <6.0

Morey 

Road

2/6/2013 SBQ 

(replicate)

E0.03 <0.10 <0.40 E0.01 <0.10 <0.10 E0.29 E0.6 <6.0

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- -- 143 --

Morey 

Road

6/25/2013 SB <0.10 <0.50 <0.20 <0.10 <0.10 <0.10 <0.20 E0.3 <6.0

Morey 

Road

6/25/2013 SBQ 

(replicate)

E0.25 <0.50 <0.20 <0.10 <0.10 <0.10 <0.20 E0.3 <6.0

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- -- 0 --

Loop 410 7/22/2014 SB <0.10 <0.10 <0.50 <0.10 <0.10 <0.10 E0.43 <1.0 <6.0

Loop 410 7/22/2014 SBQ 

(replicate)

<0.10 <0.10 <0.40 <0.10 <0.10 <0.10 0.38 <1.0 <6.0

RPD of replicate sample 

concentrations:

-- -- -- -- -- -- 12 -- --

Morey 

Road

5/24/2013 SS E0.18 <0.50 <1.00 E0.01 <0.10 <0.10 E1.5 E0.2 <6.0

Morey 

Road

5/24/2013 SSQ 

(replicate)

E0.27 <0.50 <2.00 0.02 <0.10 <0.20 1.83 <1.0 <6.0

RPD of replicate sample 

concentrations:

40 -- -- 67 -- -- 20 -- --

Rodriguez 

Park

4/30/2013 SS E0.35 <0.10 E2.35 E0.03 <0.10 E0.20 E2.59 E0.3 <6.0

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

E0.30 <0.10 E2.02v E0.02 <0.10 E0.15 E2.22v E0.4 <6.0

RPD of replicate sample 

concentrations:

15 -- 15 40 -- 29 15 29 --
52 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 3. Relative percent difference (RPD) of concentrations of inorganic and organic constituents in duplicate streambed- and 

suspended-sediment samples collected from sites on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; --, no data; SB, bottom material; SBQ, QC sample - bottom material; SS, suspended sediment; SSQ, QC sample - suspended sediment; 

<, less than; E, estimated; v, analyte detected in laboratory blank]

Site identifier

(table 1) Date

Medium 

code 

(QC sample 

type)

Octachlorostyrene

(micrograms 

per 

kilogram)

Pentabromotoluene

(micrograms 

per 

kilogram)

Triclosan

(micrograms 

per 

kilogram)

Organic 

carbon

(percent)

Thorium

(milligrams 

per 

kilogram)

Uranium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB <1.0 <1.0 -- 0.60 5.7 2.3

Loop 410 11/15/2012 SBQ 

(replicate)

<1.0 <1.0 -- 0.23 5.7 2.3

RPD of replicate sample 

concentrations:

-- -- -- 89 0 0

Joint Base 11/16/2012 SB <1.0 <1.0 -- 1.88 7.7 1.9

Joint Base 11/16/2012 SBQ 

(replicate)

<1.0 <1.0 -- 1.56 7.7 1.9

RPD of replicate sample 

concentrations:

-- -- -- 19 0 0

Loop 410 5/14/2013 SB <1.0 <1.0 -- 0.85 5.6 2.1

Loop 410 5/14/2013 SBQ 

(replicate)

<1.0 <1.0 <4.0 0.85 5.4 2.0

RPD of replicate sample 

concentrations:

-- -- -- 0 4 5

Loop 410 2/7/2013 SB <1.0 <1.0 -- 0.86 5.2 2.0

Loop 410 2/7/2013 SBQ 

(replicate)

<1.0 <1.0 -- 0.65 5.2 2.0

RPD of replicate sample 

concentrations:

-- -- -- 28 0 0

Morey Road 2/6/2013 SB <1.0 <1.0 -- 1.58 6.5 1.8

Morey Road 2/6/2013 SBQ 

(replicate)

<1.0 <1.0 -- 1.55 6.4 2.0

RPD of replicate sample 

concentrations:

-- -- -- 2 2 11

Morey Road 6/25/2013 SB <1.0 <1.0 <4.0 1.39 6.6 1.7

Morey Road 6/25/2013 SBQ 

(replicate)

<1.0 <1.0 <4.0 1.50 6.4 1.6

RPD of replicate sample 

concentrations:

-- -- -- 8 3 6

Loop 410 7/22/2014 SB <1.0 <1.0 <4.0 0.77 5.0 2.2

Loop 410 7/22/2014 SBQ 

(replicate)

<1.0 <1.0 <4.0 0.81 5.0 2.3

RPD of replicate sample 

concentrations:

-- -- -- 5 0 4

Morey Road 5/24/2013 SS <1.0 <1.0 <4.0 1.37 6.7 1.9

Morey Road 5/24/2013 SSQ 

(replicate)

<1.0 <1.0 <4.0 1.66 6.9 1.9

RPD of replicate sample 

concentrations:

-- -- -- 19 3 0

Rodriguez 

Park

4/30/2013 SS <1.0 <1.0 -- 3.04 7.4 1.7

Rodriguez 

Park

4/30/2013 SSQ 

(replicate)

<1.0 <1.0 -- 3.08 7.3 1.7

RPD of replicate sample 

concentrations:

-- -- -- 1 1 0
Table 6 53

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

alphaEndosulfan Benfluralin betaEndosulfan Chlorpyrifos cis-Chlordane cis-Nonachlor

201433804 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201433804 Spike, percent recovery 

(acceptable range)

115.2 (21–165) 65.9 (10–124) 132.2 (21–165) 106.2 (19–169) 123.2 (32–170) 122.5 (42–156)

201432811 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201432811 Spike, percent recovery 

(acceptable range)

61.0 (21–165) 24.9 (10–124) 111.8 (21–165) 55.8 (19–169) 46.2 (32–170) 49.1 (42–156)

201425501 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201425501 Spike, percent recovery 

(acceptable range)

112.6 (21–165) 39.4 (10–124) 139.1 (21–165) 112.4 (19–169) 107.9 (32–170) 111.8 (42–156)

201326608 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201326608 Spike, percent recovery 

(acceptable range)

42.0 (21–165) 25.7 (10–124) 43.1 (21–165) 51.7 (19–169) 34.6 (32–170) 27.0 (42–156)

201320406 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201320406 Spike, percent recovery 

(acceptable range)

186.9 (21–165) 46.3 (10–124) 258.5 (21–165) 234.0 (19–169) 86.8 (32–170) 130.2 (42–156)

201316313 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201316313 Spike, percent recovery 

(acceptable range)

59.9 (21–165) 46.8 (10–124) 79.0 (21–165) 73.9 (19–169) 47.3 (32–170) 51.6 (42–156)

201312803 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201312803 Spike, percent recovery 

(acceptable range)

53.5 (21–165) 15.8 (10–124) 63.7 (21–165) 60.9 (19–169) 53.7 (32–170) 56.2 (42–156)

201234302 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.2 <0.2 <0.2 <0.1

201234302 Spike, percent recovery 

(acceptable range)

29.4 (21–165) 28.2 (10–124) 70.3 (21–165) 62.0 (19–169) 49.8 (32–170) 57.9 (42–156)

Table 6
54 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units Cyfluthrin DCPA (Dacthal)

Desulfinylfipronil Dieldrin Endosulfan 

sulfate

201433804 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201433804 Spike, percent recovery 

(acceptable range)

128.4 (15–123) 129.9 (52–136) 103.0 (16–148) 123.5 (47–161) 123.9 (21–165)

201432811 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201432811 Spike, percent recovery 

(acceptable range)

49.1 (15–123) 100.4 (52–136) 94.4 (16–148) 64.4 (47–161) 107.6 (21–165)

201425501 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201425501 Spike, percent recovery 

(acceptable range)

119.6 (15–123) 93.2 (52–136) 93.7 (16–148) 125.2 (47–161) 127.7 (21–165)

201326608 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201326608 Spike, percent recovery 

(acceptable range)

43.6 (15–123) 34.1 (52–136) 33.1 (16–148) 39.5 (47–161) 55.2 (21–165)

201320406 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201320406 Spike, percent recovery 

(acceptable range)

504.5 (15–123) 92.3 (52–136) 283.6 (16–148) 89.8 (47–161) 435.3 (21–165)

201316313 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201316313 Spike, percent recovery 

(acceptable range)

66.9 (15–123) 61.9 (52–136) 56.4 (16–148) 51.4 (47–161) 82.6 (21–165)

201312803 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201312803 Spike, percent recovery 

(acceptable range)

77.2 (15–123) 58.2 (52–136) 44.7 (16–148) 45.7 (47–161) 63.0 (21–165)

201234302 Blank, micrograms per 

kilogram

<0.2 <0.2 <0.1 <0.1 <0.4

201234302 Spike, percent recovery 

(acceptable range)

64.6 (15–123) 77.8 (52–136) 75.7 (16–148) 46.4 (47–161) 73.8 (21–165)
Table 6 55

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units Fipronil sulfide Fipronil Hexachlorobenzene

lambdaCyhalothrin Oxychlordane

201433804 Blank, micrograms per 

kilogram

<0.1 E0.43 0.03 <0.2 <1

201433804 Spike, percent recovery 

(acceptable range)

100.0 (28–148) 109.6 (33–123) 97.0 (20–158) 104.9 (8–156) 106.7 (32–164)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 0.019 <0.2 <1

201432811 Spike, percent recovery 

(acceptable range)

94.5 (28–148) 98.5 (33–123) 34.9 (20–158) 36.6 (8–156) 35.8 (32–164)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.1 0.014 <0.2 <1

201425501 Spike, percent recovery 

(acceptable range)

97.9 (28–148) 126.0 (33–123) 80.1 (20–158) 74.9(8–156) 106.0 (32–164)

201326608 Blank, micrograms per 

kilogram

<0.1 -- <0.1 <0.2 <1

201326608 Spike, percent recovery 

(acceptable range)

26.2 (28–148) -- 14.9 (20–158) 41.6 (8–156) 25.4 (32–164)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.1 0.013 <0.2 <1

201320406 Spike, percent recovery 

(acceptable range)

85.7 (28–148) -- 53.1 (20–158) 376.3 (8–156) 72.5 (32–164)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.2 <1

201316313 Spike, percent recovery 

(acceptable range)

40.3 (28–148) 0.0 (33–123) 46.3 (20–158) 45.3(8–156) 40.6 (32–164)

201312803 Blank, micrograms per 

kilogram

<0.1 -- <0.1 <0.2 <1

201312803 Spike, percent recovery 

(acceptable range)

46.6 (28–148) -- 21.9 (20–158) 44.4 (8–156) 46.7 (32–164)

201234302 Blank, micrograms per 

kilogram

<0.1 -- 0.019 <0.2 <1

201234302 Spike, percent recovery 

(acceptable range)

22.6 (28–148) -- 45.4 (20–158) 37.1 (8–156) 33.6 (32–164)
56 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units Oxyfluorfen p,p'-DDD p,p'-DDE p,p'-DDT Pendimethalin

201433804 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201433804 Spike, percent recovery 

(acceptable range)

117.4 (33–153) 123.1 (13–147) 119.9 (25–151) 116.8 (22–156) 107.5 (50–146)

201432811 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201432811 Spike, percent recovery 

(acceptable range)

71.3 (33–153) 53.6 (13–147) 56.4 (25–151) 52.5 (22–156) 53.3 (50–146)

201425501 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201425501 Spike, percent recovery 

(acceptable range)

108.1 (33–153) 115.8 (13–147) 105.5 (25–151) 127.4 (22–156) 86.9 (50–146)

201326608 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201326608 Spike, percent recovery 

(acceptable range)

46.0 (33–153) 38.5 (13–147) 30.4 (25–151) 38.6 (22–156) 41.0 (50–146)

201320406 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201320406 Spike, percent recovery 

(acceptable range)

96.7 (33–153) 118.5 (13–147) 48.9 (25–151) 222.8 (22–156) 237.0 (50–146)

201316313 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201316313 Spike, percent recovery 

(acceptable range)

73.0 (33–153) 51.8 (13–147) 46.0 (25–151) 79.4 (22–156) 65.4 (50–146)

201312803 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201312803 Spike, percent recovery 

(acceptable range)

76.5 (33–153) 44.2 (13–147) 58.7 (25–151) 52.8 (22–156) 63.7 (50–146)

201234302 Blank, micrograms per 

kilogram

<4 <2 <1 <4 <1

201234302 Spike, percent recovery 

(acceptable range)

72.0 (33–153) 61.9 (13–147) 42.5 (25–151) 52.9 (22–156) 66.7 (50–146)
Table 6 57

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

Pentachloroanisole

Pentachloronitrobenzene

Tefluthrin Tetradifon transChlordane

201433804 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201433804 Spike, percent recovery 

(acceptable range)

100.2 (35–155) 99.0 (48–162) 103.1 (43–127) 100.0 (60–138) 115.2 (39–165)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201432811 Spike, percent recovery 

(acceptable range)

47.7 (35–155) 50.8 (48–162) 39.1 (43–127) 72.5 (60–138) 45.3 (39–165)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201425501 Spike, percent recovery 

(acceptable range)

74.1 (35–155) 70.6 (48–162) 101.8 (43–127) 98.5 (60–138) 112.5 (39–165)

201326608 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201326608 Spike, percent recovery 

(acceptable range)

17.3 (35–155) 25.8 (48–162) 36.9 (43–127) 32.3 (60–138) 33.8 (39–165)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201320406 Spike, percent recovery 

(acceptable range)

53.6 (35–155) 117.6 (48–162) 71.6 (43–127) 109.8 (60–138) 83.5 (39–165)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201316313 Spike, percent recovery 

(acceptable range)

46.8 (35–155) 60.2 (48–162) 52.4 (43–127) 53.2 (60–138) 52.2 (39–165)

201312803 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201312803 Spike, percent recovery 

(acceptable range)

20.9 (35–155) 21.3 (48–162) 49.1 (43–127) 55.4 (60–138) 53.4 (39–165)

201234302 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.5 <0.2 <0.2

201234302 Spike, percent recovery 

(acceptable range)

42.7 (35–155) 55.5 (48–162) 40.3 (43–127) 62.5 (60–138) 40.1 (39–165)
58 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

transNonachlor Trifluralin PCB 

congener 101

PCB 

congener 110

PCB 

congener 118

201433804 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201433804 Spike, percent recovery 

(acceptable range)

117.5 (28–160) 67.1 (12–138) 123.6 (10–130) 130.3 (16–130) 124.5 (35–155)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201432811 Spike, percent recovery 

(acceptable range)

44.1 (28–160) 25.4 (12–138) 51.6 (10–130) 47.7 (16–130) 48.2 (35–155)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201425501 Spike, percent recovery 

(acceptable range)

109.3 (28–160) 37.0 (12–138) 97.4 (10–130) 101.0 (16–130) 103.2 (35–155)

201326608 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201326608 Spike, percent recovery 

(acceptable range)

28.2 (28–160) 24.6 (12–138) 21.5 (10–130) 23.2 (16–130) 25.3 (35–155)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201320406 Spike, percent recovery 

(acceptable range)

108.6 (28–160) 41.2 (12–138) 40.7 (10–130) 41.6 (16–130) 41.4 (35–155)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201316313 Spike, percent recovery 

(acceptable range)

51.0 (28–160) 43.1 (12–138) 27.2 (10–130) 26.6 (16–130) 35.0 (35–155)

201312803 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201312803 Spike, percent recovery 

(acceptable range)

49.6 (28–160) 14.3 (12–138) 30.8 (10–130) 41.2 (16–130) 29.6 (35–155)

201234302 Blank, micrograms per 

kilogram

<0.1 <0.2 <1 <1 <0.1

201234302 Spike, percent recovery 

(acceptable range)

45.3 (28–160) 32.8 (12–138) 9.2 (10–130) 28.6 (16–130) 56.0 (35–155)
Table 6 59

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

PCB 

congener 138

PCB 

congener 146

PCB 

congener 149

PCB 

congener 151

PCB 

congener 170

201433804 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201433804 Spike, percent recovery 

(acceptable range)

122.8 (27–155) 121.3 (37–145) 115.9 (12–114) 117.3 (21–141) 119.8 (28–154)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201432811 Spike, percent recovery 

(acceptable range)

49.7 (27–155) 47.5 (37–145) 45.3 (12–114) 45.3 (21–141) 49.7 (28–154)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201425501 Spike, percent recovery 

(acceptable range)

101.4 (27–155) 102.7 (37–145) 100.1 (12–114) 95.6 (21–141) 98.4 (28–154)

201326608 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201326608 Spike, percent recovery 

(acceptable range)

21.1 (27–155) 21.2 (37–145) 21.6 (12–114) 20.5 (21–141) 21.4 (28–154)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201320406 Spike, percent recovery 

(acceptable range)

43.2 (27–155) 36.0 (37–145) 38.9 (12–114) 40.5 (21–141) 44.0 (28–154)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201316313 Spike, percent recovery 

(acceptable range)

26.0 (27–155) 27.4 (37–145) 44.9 (12–114) 25.7 (21–141) 27.9 (28–154)

201312803 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201312803 Spike, percent recovery 

(acceptable range)

33.4 (27–155) 29.9 (37–145) 31.7 (12–114) 34.7 (21–141) 29.3 (28–154)

201234302 Blank, micrograms per 

kilogram

<0.1 <0.1 <1 <0.1 <0.1

201234302 Spike, percent recovery 

(acceptable range)

21.3 (27–155) 46.6 (37–145) 10.9 (12–114) 56.9 (21–141) 69.6 (28–154)
60 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

PCB 

congener 174

PCB 

congener 177

PCB 

congener 180

PCB 

congener 183

PCB 

congener 187

201433804 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201433804 Spike, percent recovery 

(acceptable range)

118.5 (51–135) 119.4 (38–140) 121.4 (40–142) 119.1 (34–142) 116.9 (33–153)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201432811 Spike, percent recovery 

(acceptable range)

46.9 (51–135) 47.5 (38–140) 49.0 (40–142) 46.1 (34–142) 46.4 (33–153)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.1 0.009 <0.1 <0.1

201425501 Spike, percent recovery 

(acceptable range)

97.6 (51–135) 96.9 (38–140) 100.0 (40–142) 97.6 (34–142) 96.2 (33–153)

201326608 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201326608 Spike, percent recovery 

(acceptable range)

20.8 (51–135) 20.7 (38–140) 20.8 (40–142) 20.8 (34–142) 20.7 (33–153)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201320406 Spike, percent recovery 

(acceptable range)

42.6 (51–135) 42.4 (38–140) 42.7 (40–142) 40.5 (34–142) 40.5 (33–153)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201316313 Spike, percent recovery 

(acceptable range)

27.0 (51–135) 26.8 (38–140) 27.9 (40–142) 26.4 (34–142) 26.0 (33–153)

201312803 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201312803 Spike, percent recovery 

(acceptable range)

30.5 (51–135) 29.9 (38–140) 29.4 (40–142) 30.9 (34–142) 29.8 (33–153)

201234302 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201234302 Spike, percent recovery 

(acceptable range)

25.0 (51–135) 21.9 (38–140) 66.4 (40–142) 64.3 (34–142) 61.5 (33–153)
Table 6 61

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

PCB 

congener 194

PCB 

congener 206

PCB 

congener 49

PCB 

congener 52

PCB 

congener 70

201433804 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201433804 Spike, percent recovery 

(acceptable range)

118.0 (57–135) 118.7 (66–120) 135.1 (9–113) 123.2 (4–112) 131.2 (9–115)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201432811 Spike, percent recovery 

(acceptable range)

49.4 (57–135) 50.1 (66–120) 60.7 (9–113) 43.7 (4–112) 48.5 (9–115)

201425501 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201425501 Spike, percent recovery 

(acceptable range)

98.6 (57–135) 96.5 (66–120) 106.9 (9–113) 91.5 (4–112) 112.7 (9–115)

201326608 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201326608 Spike, percent recovery 

(acceptable range)

21.5 (57–135) 21.9 (66–120) 19.1 (9–113) 21.8 (4–112) 21.9 (9–115)

201320406 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201320406 Spike, percent recovery 

(acceptable range)

45.7 (57–135) 40.6 (66–120) 38.4 (9–113) 35.3 (4–112) 37.5 (9–115)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201316313 Spike, percent recovery 

(acceptable range)

28.7 (57–135) 30.3 (66–120) 28.2 (9–113) 39.2 (4–112) 34.5 (9–115)

201312803 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201312803 Spike, percent recovery 

(acceptable range)

29.8 (57–135) 30.6 (66–120) 44.8 (9–113) 31.5 (4–112) 30.5 (9–115)

201234302 Blank, micrograms per 

kilogram

<0.1 <0.1 <2 <1 <2

201234302 Spike, percent recovery 

(acceptable range)

20.3 (57–135) 30.3 (66–120) 18.0 (9–113) 24.0 (4–112) 49.5 (9–115)
62 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

1,2-Bis(2,4,6-

tribromophenoxy)-

ethane

PBDE 

congener 100

PBDE 

congener 138

PBDE 

congener 153

PBDE 

congener 154

201433804 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201433804 Spike, percent recovery 

(acceptable range)

126.3 (49–157) 124.1 (27–159) 104.1 (28–166) 125.4 (38–158) 117.9 (47–143)

201432811 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201432811 Spike, percent recovery 

(acceptable range)

55.1 (49–157) 67.7 (27–159) 48.9 (28–166) 52.1 (38–158) 52.8 (47–143)

201425501 Blank, micrograms per 

kilogram

<0.1 0.051 <0.1 <0.1 <0.1

201425501 Spike, percent recovery 

(acceptable range)

114.4 (49–157) 118.8 (27–159) 122.0 (28–166) 127.8 (38–158) 132.8 (47–143)

201326608 Blank, micrograms per 

kilogram

<0.1 0.12 <0.1 <0.1 <0.1

201326608 Spike, percent recovery 

(acceptable range)

42.6 (49–157) 60.0 (27–159) 48.1 (28–166) 45.7 (38–158) 46.2 (47–143)

201320406 Blank, micrograms per 

kilogram

<0.1 0.012 <0.1 <0.1 <0.1

201320406 Spike, percent recovery 

(acceptable range)

194.9 (49–157) 112.9 (27–159) 198.3 (28–166) 123.9 (38–158) 116.4 (47–143)

201316313 Blank, micrograms per 

kilogram

<0.1 <0.1 <0.1 <0.1 <0.1

201316313 Spike, percent recovery 

(acceptable range)

149.7 (49–157) 58.0 (27–159) 89.9 (28–166) 79.7 (38–158) 65.3 (47–143)

201312803 Blank, micrograms per 

kilogram

<0.1 0.19 <0.1 <0.1 <0.1

201312803 Spike, percent recovery 

(acceptable range)

72.7 (49–157) 58.2 (27–159) 70.2 (28–166) 56.6 (38–158) 53.5 (47–143)

201234302 Blank, micrograms per 

kilogram

<0.1 0.086 <0.1 <0.1 <0.1

201234302 Spike, percent recovery 

(acceptable range)

61.6 (49–157) 99.9 (27–159) 56.5 (28–166) 68.4 (38–158) 61.6 (47–143)
Table 6 63

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

PBDE 

congener 183

PBDE 

congener 47

PBDE 

congener 66

PBDE 

congener 71

PBDE 

congener 85

201433804 Blank, micrograms per 

kilogram

<0.1 0.16 <0.1 <0.1 <0.1

201433804 Spike, percent recovery 

(acceptable range)

108.4 (36–162) 194.0 (24–192) 122.7 (11–137) 125.9 (37–163) 115.6 (36–168)

201432811 Blank, micrograms per 

kilogram

<0.1 0.31 <0.1 0.28 <0.1

201432811 Spike, percent recovery 

(acceptable range)

53.5 (36–162) 226.1 (24–192) 57.5 (11–137) 48.7 (37–163) 51.9 (36–168)

201425501 Blank, micrograms per 

kilogram

<0.1 0.25 <0.1 <0.1 <0.1

201425501 Spike, percent recovery 

(acceptable range)

107.2 (36–162) 188.1 (24–192) 124.5 (11–137) 124.4 (37–163) 133.0 (36–168)

201326608 Blank, micrograms per 

kilogram

<0.1 1.3 <0.1 <0.1 <0.1

201326608 Spike, percent recovery 

(acceptable range)

41.4 (36–162) 318.2 (24–192) 45.1 (11–137) 39.3 (37–163) 49.8 (36–168)

201320406 Blank, micrograms per 

kilogram

<0.1 0.32 <0.1 <0.1 <0.1

201320406 Spike, percent recovery 

(acceptable range)

241.3 (36–162) 179.9 (24–192) 107.6 (11–137) 98.8 (37–163) 154.8 (36–168)

201316313 Blank, micrograms per 

kilogram

<0.1 0.17 <0.1 <0.1 <0.1

201316313 Spike, percent recovery 

(acceptable range)

85.4 (36–162) 112.7 (24–192) 65.6 (11–137) 54.8 (37–163) 79.4 (36–168)

201312803 Blank, micrograms per 

kilogram

<0.1 0.3 <0.1 <0.1 <0.1

201312803 Spike, percent recovery 

(acceptable range)

69.5 (36–162) 116.0 (24–192) 58.3 (11–137) 55.2 (37–163) 62.8 (36–168)

201234302 Blank, micrograms per 

kilogram

<0.1 1.2 <0.1 <0.1 <0.1

201234302 Spike, percent recovery 

(acceptable range)

64.0 (36–162) 280.7 (24–192) 58.6 (11–137) 58.4 (37–163) 69.0 (36–168)
64 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 6. Concentration of organic constituents in U.S. Geological Survey National Water Quality Laboratory quality-control samples 

included with sample sets for stream-sediment samples collected from Leon Creek, San Antonio, Texas, 2012–14.—Continued

[--, no data; <, less than; E, estimated]

Set 

number

Sample 

identifier, units

PBDE 

congener 99

Bis(hexachlorocyclopentadieno) 

cyclooctane

Methyl 

triclosan

OctachlorostyrenePentabromotoluene Triclosan

201433804 Blank, micrograms per 

kilogram

0.043 <1 <6 <1 <1 <4

201433804 Spike, percent recovery 

(acceptable range)

133.5 (27–183) 119.2 (44–170) 60.8 (30–156) 114.8 (42–126) 112.6 (69–141) 4.7 (14–170)

201432811 Blank, micrograms per 

kilogram

0.11 <1 <6 <1 <1 E1.4

201432811 Spike, percent recovery 

(acceptable range)

109.7 (27–183) 53.4 (44–170) 30.4 (30–156) 39.3 (42–126) 48.5 (69–141) 28.9 (14–170)

201425501 Blank, micrograms per 

kilogram

0.16 <1 <6 <1 <1 <4

201425501 Spike, percent recovery 

(acceptable range)

158.6 (27–183) 111.4 (44–170) 118.7 (30–156) 92.5 (42–126) 114.8 (69–141) 2.8 (14–170)

201326608 Blank, micrograms per 

kilogram

0.39 <1 <6 <1 <1 <4

201326608 Spike, percent recovery 

(acceptable range)

93.3 (27–183) 40.9 (44–170) 40.8 (30–156) 25.5 (42–126) 38.1 (69–141) 7.7 (14–170)

201320406 Blank, micrograms per 

kilogram

0.078 <1 <6 <1 <1 <4

201320406 Spike, percent recovery 

(acceptable range)

137.8 (27–183) 128.9 (44–170) 85.6 (30–156) 49.6 (42–126) 132.6 (69–141) 50.0 (14–170)

201316313 Blank, micrograms per 

kilogram

0.073 <1 <6 <1 <1 <4

201316313 Spike, percent recovery 

(acceptable range)

73.1 (27–183) 80.4 (44–170) 56.7 (30–156) 46.7 (42–126) 64.4 (69–141) 0.0 (14–170)

201312803 Blank, micrograms per 

kilogram

0.085 <1 <6 <1 <1 --

201312803 Spike, percent recovery 

(acceptable range)

71.1 (27–183) 58.8 (44–170) 51.4 (30–156) 42.1 (42–126) 64.0 (69–141) --

201234302 Blank, micrograms per 

kilogram

0.23 <1 <6 <1 <1 --

201234302 Spike, percent recovery 

(acceptable range)

218.6 (27–183) 60.0 (44–170) 58.9 (30–156) 47.4 (42–126) 58.8 (69–141) --
Table 8 65

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Station 

number

Station 

name

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

NWQL set 

number

Calcium

(milligrams 

per 

kilogram)

Magnesium

(milligrams 

per 

kilogram)

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SB 201234302 210,000 5,800

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 11/15/2012 SBQ 

(replicate)

201234302 200,000 5,700

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 01/09/2013 SS 201312803 Insufficient 

sediment

Insufficient 

sediment

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 02/07/2013 SB 201312803 210,000 5,800

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 02/07/2013 SBQ 

(replicate)

201316313 200,000 5,800

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 04/29/2013 SS 201316313 190,000 5,500

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/14/2013 SB 201316313 190,000 6,000

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/14/2013 SBQ 

(replicate)

201320406 200,000 5,900

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 05/24/2013 SS 201320406 200,000 5,700

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 06/25/2013 SB 201326608 180,000 7,200

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 06/25/2014 SS 201425501 170,000 6,200

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 07/22/2014 SB 201432811 210,000 6,300

08181435 Leon Creek at Loop 410 at 

San Antonio, Tex.

Loop 410 07/22/2014 SBQ 

(replicate)

201432811 210,000 6,300

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

11/15/2012 SB 201234302 160,000 6,000

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

02/07/2013 SB 201312803 170,000 5,900

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

04/29/2013 SS 201316313 150,000 5,800

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

201316313 150,000 5,600

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

05/14/2013 SB 201320406 160,000 6,200

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

05/24/2013 SS 201320406 160,000 5,800

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

06/24/2013 SB 201326608 160,000 6,200

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

06/25/2014 SS 201425501 120,000 7,300

292443098364600 Leon Creek at Rodriguez 

Park, San Antonio, Tex.

Rodriguez 

Park

07/21/2014 SB 201433804 160,000 6,000

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

11/15/2012 SB 201234302 150,000 6,900

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

01/09/2013 SS -- Insufficient 

sediment

Insufficient 

sediment

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites on 

Leon Creek, San Antonio, Texas, 2012–14.

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above the 

detection level; t, below the detection level; v, analyte detected in laboratory blank]

Table 8
66 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Station 

number

Station 

name

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

NWQL set 

number

Calcium

(milligrams 

per 

kilogram)

Magnesium

(milligrams 

per 

kilogram)

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

02/06/2013 SB 201312803 160,000 6,300

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

02/06/2013 SBQ 

(replicate)

201316313 160,000 6,100

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

04/29/2013 SS 201316313 Insufficient 

sediment

Insufficient 

sediment

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/13/2013 SB 201320406 160,000 6,200

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/24/2013 SS 201320406 150,000 6,000

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

05/24/2013 SSQ 

(replicate)

201320406 130,000 6,200

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2013 SB 201320406 160,000 6,500

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2013 SBQ 

(replicate)

201320406 140,000 6,000

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

06/25/2014 SS 201425501 110,000 8,000

292338098360501 Leon Creek at Morey Road, 

San Antonio, Tex.

Morey 

Road

07/21/2014 SB 201433804 160,000 6,800

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 11/16/2012 SB 201234302 120,000 7,300

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 11/16/2012 SBQ 

(replicate)

201234302 120,000 7,200

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 02/06/2013 SB 201312803 120,000 6,900

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 05/13/2013 SB 201316313 120,000 6,500

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 06/24/2013 SB 201320406 130,000 7,600

292240098353600 Leon Creek at Lackland Air 

Force Base Golf Course, 

San Antonio, Tex.

Joint Base 07/21/2014 SB 201433804 120,000 6,700

88480206 USGS Central Tex. PO at 

Ferguson Ln, Austin, Tex.

-- 11/28/2012 SBQ (standard 

reference 

material)

201235310 23,000 11,000

88480206 USGS Central Tex. PO at 

Ferguson Ln, Austin, Tex.

-- 04/09/2013 SBQ (standard 

reference 

material)

201316313 25,000 11,000
Table 8 67

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Potassium

(milligrams 

per 

kilogram)

Sodium

(milligrams 

per

kilogram)

Carbon 

[inorganic 

plus organic]

(percent)

Inorganic 

carbon

(percent)

Phosphorus

(milligrams 

per 

kilogram)

Aluminum

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 9,600 820 6.5 5.9 590 37,000

Loop 410 11/15/2012 SBQ 

(replicate)

9,300 780 6.0 5.8 560 37,000

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Loop 410 02/07/2013 SB 8,800 760 6.9 6.0 590 36,000

Loop 410 02/07/2013 SBQ 

(replicate)

8,600 740 6.8 6.1 570 36,000

Loop 410 04/29/2013 SS 7,100 700 10 5.9 1,100 34,000

Loop 410 05/14/2013 SB 8,800 800 6.8 5.9 600 36,000

Loop 410 05/14/2013 SBQ 

(replicate)

8,600 770 6.8 6.0 610 35,000

Loop 410 05/24/2013 SS 7,300 930 7.8 6.1 680 30,000

Loop 410 06/25/2013 SB 10,000 900 5.6 5.0 680 41,000

Loop 410 06/25/2014 SS 7,600 760 Insufficient 

sediment

Insufficient 

sediment

920 44,000

Loop 410 07/22/2014 SB 9,200 830 7.2 6.5 620 33,000

Loop 410 07/22/2014 SBQ 

(replicate)

8,900 770 7.4 6.6 610 31,000

Rodriguez 

Park

11/15/2012 SB 8,900 1,200 6.0 4.5 650 42,000

Rodriguez 

Park

02/07/2013 SB 8,600 1,200 6.5 4.9 650 40,000

Rodriguez 

Park

04/29/2013 SS 10,000 700 7.5 4.5 1,000 49,000

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

9,600 800 7.7 4.6 1,000 47,000

Rodriguez 

Park

05/14/2013 SB 7,900 1,200 5.6 4.8 630 39,000

Rodriguez 

Park

05/24/2013 SS 9,100 1,100 6.7 4.8 750 38,000

Rodriguez 

Park

06/24/2013 SB 8,800 1,100 6.6 4.9 730 35,000

Rodriguez 

Park

06/25/2014 SS 8,700 710 Insufficient 

sediment

Insufficient 

sediment

1,200 52,000
68 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Potassium

(milligrams 

per 

kilogram)

Sodium

(milligrams 

per

kilogram)

Carbon 

[inorganic 

plus organic]

(percent)

Inorganic 

carbon

(percent)

Phosphorus

(milligrams 

per 

kilogram)

Aluminum

(milligrams 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 9,000 1,000 6.8 4.7 740 41,000

Morey Road 11/15/2012 SB 10,000 1,800 5.6 4.0 1,000 49,000

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 10,000 2,200 6.3 4.7 940 43,000

Morey Road 02/06/2013 SBQ 

(replicate)

9,800 2,100 6.2 4.6 910 44,000

Morey Road 04/29/2013 SS Insufficient 

sediment

Insufficient 

sediment

8.5 3.9 Insufficient 

sediment

Insufficient 

sediment

Morey Road 05/13/2013 SB 9,200 1,800 6.0 4.8 1,000 42,000

Morey Road 05/24/2013 SS 10,000 4,170 5.8 4.4 810 38,000

Morey Road 05/24/2013 SSQ 

(replicate)

11,000 4,660 5.5 3.8 810 42,000

Morey Road 06/25/2013 SB 11,000 2,100 6.0 4.6 1,000 38,000

Morey Road 06/25/2013 SBQ 

(replicate)

10,000 2,100 6.0 4.5 980 34,000

Morey Road 06/25/2014 SS 10,000 1,370 Insufficient 

sediment

Insufficient 

sediment

1,300 59,000

Morey Road 07/21/2014 SB 9,900 1,900 6.4 4.7 980 43,000

Joint Base 11/16/2012 SB 11,000 3,300 5.0 3.1 790 50,000

Joint Base 11/16/2012 SBQ 

(replicate)

11,000 3,400 4.8 3.2 780 50,000

Joint Base 02/06/2013 SB 11,000 3,400 5.4 3.7 860 45,000

Joint Base 05/13/2013 SB 10,000 3,000 5.0 3.9 790 43,000

Joint Base 06/24/2013 SB 12,000 3,100 5.1 3.7 880 42,000

Joint Base 07/21/2014 SB 11,000 3,000 5.8 3.8 920 44,000

-- 11/28/2012 SBQ (standard 

reference 

material)

18,000 5,400 3.4 0.82 850 59,000

-- 04/09/2013 SBQ (standard 

reference 

material)

19,000 5,600 3.1 0.87 880 60,000
Table 8 69

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Barium

(milligrams 

per 

kilogram)

Beryllium

(milligrams 

per 

kilogram)

Bismuth

(milligrams 

per 

kilogram)

Cadmium

(milligrams 

per 

kilogram)

Cesium

(milligrams 

per 

kilogram)

Chromium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 150 0.9 0.15 0.3 5.40 42

Loop 410 11/15/2012 SBQ 

(replicate)

150 1.0 0.15 0.3 5.40 40

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Loop 410 02/07/2013 SB 150 0.8 0.15 0.3 4.80 35

Loop 410 02/07/2013 SBQ 

(replicate)

140 0.7 0.15 0.3 4.80 34

Loop 410 04/29/2013 SS 170 1.0 M 0.5 <5.00 31

Loop 410 05/14/2013 SB 140 0.8 0.16 0.3 5.20 38

Loop 410 05/14/2013 SBQ 

(replicate)

140 0.8 0.17 0.3 5.10 37

Loop 410 05/24/2013 SS 150 1.0 M 0.3 4.00 33

Loop 410 06/25/2013 SB 230 1.4 0.20 0.3 7.30 47

Loop 410 06/25/2014 SS 190 1.0 M 0.4 M 40

Loop 410 07/22/2014 SB 140 0.9 0.13 0.3 5.00 42

Loop 410 07/22/2014 SBQ 

(replicate)

140 1.0 0.13 0.3 4.80 40

Rodriguez 

Park

11/15/2012 SB 200 1.3 0.22 0.3 4.70 39

Rodriguez 

Park

02/07/2013 SB 180 1.0 0.19 0.3 4.40 34

Rodriguez 

Park

04/29/2013 SS 200 1.0 M 0.4 6 37

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

200 1.0 M 0.4 5 34

Rodriguez 

Park

05/14/2013 SB 190 1.0 0.20 0.3 4.40 34

Rodriguez 

Park

05/24/2013 SS 200 1.0 M 0.3 4.80 36

Rodriguez 

Park

06/24/2013 SB 200 1.3 0.18 0.3 4.70 35

Rodriguez 

Park

06/25/2014 SS 230 2.0 M 0.4 M 45
70 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Barium

(milligrams 

per 

kilogram)

Beryllium

(milligrams 

per 

kilogram)

Bismuth

(milligrams 

per 

kilogram)

Cadmium

(milligrams 

per 

kilogram)

Cesium

(milligrams 

per 

kilogram)

Chromium

(milligrams 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 200 1.3 0.20 0.3 4.90 38

Morey Road 11/15/2012 SB 220 1.5 0.24 0.3 5.30 50

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 190 1.1 0.21 0.3 4.50 43

Morey Road 02/06/2013 SBQ 

(replicate)

190 1.1 0.21 0.3 4.50 41

Morey Road 04/29/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 05/13/2013 SB 190 1.0 0.20 0.3 4.60 44

Morey Road 05/24/2013 SS 220 1.0 M 0.2 4.10 38

Morey Road 05/24/2013 SSQ 

(replicate)

230 1.0 M 0.2 4.40 39

Morey Road 06/25/2013 SB 230 1.3 0.18 0.3 4.90 42

Morey Road 06/25/2013 SBQ 

(replicate)

220 1.3 0.17 0.3 4.70 40

Morey Road 06/25/2014 SS 240 2.0 M 0.6 M 52

Morey Road 07/21/2014 SB 220 1.3 0.21 0.3 5.00 47

Joint Base 11/16/2012 SB 260 1.3 0.27 0.6 4.80 55

Joint Base 11/16/2012 SBQ 

(replicate)

260 1.1 0.27 0.5 4.90 58

Joint Base 02/06/2013 SB 230 1.1 0.24 0.5 4.30 50

Joint Base 05/13/2013 SB 230 1.0 0.24 1.5 4.40 48

Joint Base 06/24/2013 SB 270 1.5 0.25 0.9 5.00 53

Joint Base 07/21/2014 SB 240 1.3 0.23 0.9 4.80 51

-- 11/28/2012 SBQ (standard 

reference 

material)

400 1.8 0.63 2.9 5.60 110

-- 04/09/2013 SBQ (standard 

reference 

material)

380 1.6 0.54 3.0 5.70 110
Table 8 71

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Cobalt

(milligrams 

per 

kilogram)

Copper

(milligrams 

per 

kilogram)

Gallium

(milligrams 

per 

kilogram)

Iron

(milligrams 

per 

kilogram)

Lead

(milligrams 

per 

kilogram)

Lithium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 4 11 8 14,000 9 28

Loop 410 11/15/2012 SBQ 

(replicate)

4 12 8 13,000 10 27

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Loop 410 02/07/2013 SB 4 12 8 14,000 11 19

Loop 410 02/07/2013 SBQ 

(replicate)

4 12 8 14,000 11 16

Loop 410 04/29/2013 SS 6 29 8 15,000 22 19

Loop 410 05/14/2013 SB 4 11 8 14,000 10 22

Loop 410 05/14/2013 SBQ 

(replicate)

4 11 8 14,000 11 21

Loop 410 05/24/2013 SS 4 14 8 13,000 16 23

Loop 410 06/25/2013 SB 6 14 11 20,000 15 30

Loop 410 06/25/2014 SS 6 17 10 18,000 23 32

Loop 410 07/22/2014 SB 3 12 8 12,000 15 26

Loop 410 07/22/2014 SBQ 

(replicate)

3 9 7 12,000 9 28

Rodriguez 

Park

11/15/2012 SB 7 17 10 19,000 20 23

Rodriguez 

Park

02/07/2013 SB 7 15 9 19,000 21 17

Rodriguez 

Park

04/29/2013 SS 10 24 12 22,000 20 23

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

10 16 10 21,000 21 22

Rodriguez 

Park

05/14/2013 SB 6 14 9 17,000 21 18

Rodriguez 

Park

05/24/2013 SS 6 17 9 17,000 21 25

Rodriguez 

Park

06/24/2013 SB 7 16 10 19,000 21 25

Rodriguez 

Park

06/25/2014 SS 9 20 13 23,000 24 30
72 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Cobalt

(milligrams 

per 

kilogram)

Copper

(milligrams 

per 

kilogram)

Gallium

(milligrams 

per 

kilogram)

Iron

(milligrams 

per 

kilogram)

Lead

(milligrams 

per 

kilogram)

Lithium

(milligrams 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 7 16 10 18,000 22 24

Morey Road 11/15/2012 SB 9 21 11 25,000 20 26

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 7 14 10 22,000 17 18

Morey Road 02/06/2013 SBQ 

(replicate)

7 14 9 22,000 17 17

Morey Road 04/29/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 05/13/2013 SB 7 15 10 22,000 18 20

Morey Road 05/24/2013 SS 6 15 9 17,000 19 25

Morey Road 05/24/2013 SSQ 

(replicate)

6 16 10 18,000 19 26

Morey Road 06/25/2013 SB 9 15 10 22,000 16 26

Morey Road 06/25/2013 SBQ 

(replicate)

9 15 10 22,000 16 28

Morey Road 06/25/2014 SS 8 19 14 25,000 24 37

Morey Road 07/21/2014 SB 8 16 11 22,000 18 25

Joint Base 11/16/2012 SB 6 20 11 24,000 28 27

Joint Base 11/16/2012 SBQ 

(replicate)

6 20 11 24,000 28 27

Joint Base 02/06/2013 SB 6 18 10 23,000 26 20

Joint Base 05/13/2013 SB 5 17 10 21,000 31 22

Joint Base 06/24/2013 SB 6 19 12 24,000 33 34

Joint Base 07/21/2014 SB 6 18 11 21,000 28 26

-- 11/28/2012 SBQ (standard 

reference 

material)

13 91 15 36,000 140 45

-- 04/09/2013 SBQ (standard 

reference 

material)

13 87 14 38,000 140 38
Table 8 73

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Manganese

(milligrams 

per 

kilogram)

Mercury

(milligrams 

per 

kilogram)

Molybdenum

(milligrams 

per 

kilogram)

Nickel

(milligrams 

per 

kilogram)

Niobium

(milligrams 

per 

kilogram)

Rubidium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 210 0.02 1.2 18 8 53.1

Loop 410 11/15/2012 SBQ 

(replicate)

200 0.02 1.1 17 8 51.2

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Loop 410 02/07/2013 SB 250 0.01 1.0 5 7 48.4

Loop 410 02/07/2013 SBQ 

(replicate)

240 0.01 1.0 5 6 47.1

Loop 410 04/29/2013 SS 370 0.04 1.0 12 7 44.6

Loop 410 05/14/2013 SB 250 0.01 1.1 6 7 50.7

Loop 410 05/14/2013 SBQ 

(replicate)

260 0.01 1.0 5 7 49.6

Loop 410 05/24/2013 SS 310 0.02 M 6 7 45.1

Loop 410 06/25/2013 SB 420 0.01 1.0 14 7 64.7

Loop 410 06/25/2014 SS 370 Insufficient 

sediment

M 10 8 75.0

Loop 410 07/22/2014 SB 200 0.01 1.2 6 6 47.0

Loop 410 07/22/2014 SBQ 

(replicate)

190 0.01 1.2 5 6 46.0

Rodriguez 

Park

11/15/2012 SB 840 0.02 0.6 20 10 57.9

Rodriguez 

Park

02/07/2013 SB 1,200 0.02 0.6 9 8 54.4

Rodriguez 

Park

04/29/2013 SS 1,100 0.03 1.0 17 9 66.5

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

1,400 0.04 M 17 8 61.3

Rodriguez 

Park

05/14/2013 SB 760 0.03 0.7 9 8 53.6

Rodriguez 

Park

05/24/2013 SS 380 0.02 M 9 8 57.7

Rodriguez 

Park

06/24/2013 SB 920 0.02 0.7 11 8 58.3

Rodriguez 

Park

06/25/2014 SS 1,700 Insufficient 

sediment

M 15 8 72.3
74 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Manganese

(milligrams 

per 

kilogram)

Mercury

(milligrams 

per 

kilogram)

Molybdenum

(milligrams 

per 

kilogram)

Nickel

(milligrams 

per 

kilogram)

Niobium

(milligrams 

per 

kilogram)

Rubidium

(milligrams 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 690 0.02 0.6 13 9 59.4

Morey Road 11/15/2012 SB 1,400 0.03 0.8 23 9 65.7

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 1,300 0.02 0.7 12 7 57.2

Morey Road 02/06/2013 SBQ 

(replicate)

1,200 0.02 0.7 12 7 56.5

Morey Road 04/29/2013 SS Insufficient 

sediment

0.09 Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 05/13/2013 SB 880 0.03 0.8 12 7 58.2

Morey Road 05/24/2013 SS 360 0.01 M 10 7 56.1

Morey Road 05/24/2013 SSQ 

(replicate)

340 0.02 M 11 7 59.9

Morey Road 06/25/2013 SB 1,600 0.01 0.7 13 7 63.1

Morey Road 06/25/2013 SBQ 

(replicate)

1,700 0.01 0.7 13 6 59.4

Morey Road 06/25/2014 SS 1,100 Insufficient 

sediment

M 17 9 78.6

Morey Road 07/21/2014 SB 800 0.02 0.8 14 8 64.7

Joint Base 11/16/2012 SB 310 0.03 0.7 20 10 65.4

Joint Base 11/16/2012 SBQ 

(replicate)

310 0.05 0.7 19 10 65.3

Joint Base 02/06/2013 SB 340 0.03 0.6 12 7 58.9

Joint Base 05/13/2013 SB 320 0.03 0.6 11 7 59.5

Joint Base 06/24/2013 SB 340 0.03 0.6 14 7 69.7

Joint Base 07/21/2014 SB 350 0.06 0.6 12 8 64.3

-- 11/28/2012 SBQ (standard 

reference 

material)

530 0.71 3.7 42 13 95.2

-- 04/09/2013 SBQ (standard 

reference 

material)

550 0.71 3.4 39 8 94.5
Table 8 75

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Scandium

(milligrams 

per 

kilogram)

Silver

(milligrams 

per 

kilogram)

Strontium

(milligrams 

per 

kilogram)

Thallium

(milligrams 

per 

kilogram)

Titanium

(milligrams 

per 

kilogram)

Vanadium

(milligrams 

per 

kilogram)

Loop 410 11/15/2012 SB 5 0.1 380 0.39 1,900 60

Loop 410 11/15/2012 SBQ 

(replicate)

5 0.1 370 0.35 1,800 57

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Loop 410 02/07/2013 SB 5 0.2 310 0.34 1,700 53

Loop 410 02/07/2013 SBQ 

(replicate)

4 0.2 320 0.36 1,600 52

Loop 410 04/29/2013 SS 5 <1 310 0.40 1,400 43

Loop 410 05/14/2013 SB 5 0.2 320 0.36 1,700 56

Loop 410 05/14/2013 SBQ 

(replicate)

5 0.2 340 0.36 1,600 56

Loop 410 05/24/2013 SS 5 <0.01 280 0.40 1,600 48

Loop 410 06/25/2013 SB 6 0.2 310 0.58 2,200 72

Loop 410 06/25/2014 SS 5 <0.02 240 0.60 1,800 59

Loop 410 07/22/2014 SB 5 <0.02 430 0.31 1,600 61

Loop 410 07/22/2014 SBQ 

(replicate)

4 <0.02 440 0.32 1,600 58

Rodriguez 

Park

11/15/2012 SB 6 0.1 180 0.44 2,300 55

Rodriguez 

Park

02/07/2013 SB 6 0.2 170 0.42 2,200 51

Rodriguez 

Park

04/29/2013 SS 7 <1 180 0.50 1,900 54

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

7 <1 180 0.50 1,800 52

Rodriguez 

Park

05/14/2013 SB 6 0.2 170 0.42 1,900 50

Rodriguez 

Park

05/24/2013 SS 6 <0.01 190 0.40 2,000 54

Rodriguez 

Park

06/24/2013 SB 6 0.2 180 0.44 2,000 52

Rodriguez 

Park

06/25/2014 SS 6 <0.02 190 0.60 2,100 69
76 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Scandium

(milligrams 

per 

kilogram)

Silver

(milligrams 

per 

kilogram)

Strontium

(milligrams 

per 

kilogram)

Thallium

(milligrams 

per 

kilogram)

Titanium

(milligrams 

per 

kilogram)

Vanadium

(milligrams 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 6 <0.02 170 0.47 2,200 57

Morey Road 11/15/2012 SB 7 0.1 160 0.49 2,400 74

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 6 0.2 160 0.45 2,000 63

Morey Road 02/06/2013 SBQ 

(replicate)

6 0.2 160 0.43 2,000 61

Morey Road 04/29/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 05/13/2013 SB 6 0.2 160 0.44 1,900 63

Morey Road 05/24/2013 SS 6 <0.01 180 0.40 2,000 60

Morey Road 05/24/2013 SSQ 

(replicate)

6 <0.01 180 0.40 2,200 66

Morey Road 06/25/2013 SB 7 0.1 160 0.44 2,000 66

Morey Road 06/25/2013 SBQ 

(replicate)

6 0.1 160 0.45 1,700 61

Morey Road 06/25/2014 SS 7 <0.02 190 0.60 2,400 82

Morey Road 07/21/2014 SB 7 <0.02 180 0.47 2,200 69

Joint Base 11/16/2012 SB 7 0.3 150 0.44 2,600 77

Joint Base 11/16/2012 SBQ 

(replicate)

7 0.3 150 0.45 2,600 76

Joint Base 02/06/2013 SB 6 0.3 150 0.41 2,000 68

Joint Base 05/13/2013 SB 6 0.4 150 0.42 2,000 67

Joint Base 06/24/2013 SB 7 0.3 160 0.46 2,200 76

Joint Base 07/21/2014 SB 7 0.1 160 0.43 2,200 72

-- 11/28/2012 SBQ (standard 

reference 

material)

11 0.4 130 1.1 3,900 90

-- 04/09/2013 SBQ (standard 

reference 

material)

10 0.6 120 1.0 3,400 86
Table 8 77

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Zinc

(milligrams 

per 

kilogram)

Antimony

(milligrams 

per 

kilogram)

Arsenic

(milligrams 

per 

kilogram)

alphaEndosulfan

(micrograms 

per 

kilogram)

Benfluralin

(micrograms 

per 

kilogram)

betaEndosulfan

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB 61 0.7 5.3 <0.20 <0.20 <0.20

Loop 410 11/15/2012 SBQ 

(replicate)

57 0.7 5.2 <0.20 <0.20 <0.20

Loop 410 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

<0.20 <0.20 <0.20

Loop 410 02/07/2013 SB 58 0.6 5.0 <0.20 <0.20 <0.20

Loop 410 02/07/2013 SBQ 

(replicate)

55 0.6 4.8 <0.20 <0.20 <0.20

Loop 410 04/29/2013 SS 140 1.4 8.0 <0.20 <0.20 <0.20

Loop 410 05/14/2013 SB 58 0.7 5.4 <0.20 <0.20 <0.20

Loop 410 05/14/2013 SBQ 

(replicate)

58 0.6 5.8 <0.20 <0.20 <0.20

Loop 410 05/24/2013 SS 62 0.8 6.9 <0.20 <0.20 <0.20

Loop 410 06/25/2013 SB 75 0.8 9.0 <0.20 <0.20 <0.20

Loop 410 06/25/2014 SS 110 1.1 8.6 <0.20 <0.20 <0.20

Loop 410 07/22/2014 SB 160 0.6 5.2 <0.20 <0.20 <0.20

Loop 410 07/22/2014 SBQ 

(replicate)

56 0.5 5.2 <0.20 <0.20 <0.20

Rodriguez 

Park

11/15/2012 SB 68 0.7 7.5 <0.20 <0.20 <0.20

Rodriguez 

Park

02/07/2013 SB 68 0.7 7.3 <0.20 <0.20 <0.20

Rodriguez 

Park

04/29/2013 SS 92 1.0 11 <0.20 <0.20 <0.20

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

81 1.0 10 <0.20 <0.20 <0.20

Rodriguez 

Park

05/14/2013 SB 66 0.7 6.8 <0.20 <0.20 <0.20

Rodriguez 

Park

05/24/2013 SS 76 0.8 7.4 <0.20 <0.20 <0.20

Rodriguez 

Park

06/24/2013 SB 76 0.8 9.0 <0.20 <0.20 <0.20

Rodriguez 

Park

06/25/2014 SS 140 1.1 13 0.07 t <0.20 <0.20
78 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Zinc

(milligrams 

per 

kilogram)

Antimony

(milligrams 

per 

kilogram)

Arsenic

(milligrams 

per 

kilogram)

alphaEndosulfan

(micrograms 

per 

kilogram)

Benfluralin

(micrograms 

per 

kilogram)

betaEndosulfan

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 100 0.7 7.0 <0.20 <0.20 <0.20

Morey Road 11/15/2012 SB 92 0.7 11 <0.20 <0.20 <0.20

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 73 0.6 7.4 <0.20 <0.20 <0.20

Morey Road 02/06/2013 SBQ 

(replicate)

71 0.6 7.3 <0.20 <0.20 <0.20

Morey Road 04/29/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

<0.20 <0.20 <0.20

Morey Road 05/13/2013 SB 82 0.7 8.1 <0.20 <0.20 <0.20

Morey Road 05/24/2013 SS 72 0.7 6.4 <0.20 <0.20 <0.20

Morey Road 05/24/2013 SSQ 

(replicate)

72 0.6 6.5 <0.20 <0.20 <0.20

Morey Road 06/25/2013 SB 81 0.6 12 <0.20 <0.20 <0.20

Morey Road 06/25/2013 SBQ 

(replicate)

79 0.5 13 <0.20 <0.20 <0.20

Morey Road 06/25/2014 SS 140 1.1 11 <0.20 <0.20 <0.20

Morey Road 07/21/2014 SB 85 0.7 8.3 <0.20 <0.20 <0.20

Joint Base 11/16/2012 SB 99 0.9 6.2 <0.20 <0.20 <0.20

Joint Base 11/16/2012 SBQ 

(replicate)

98 0.9 6.1 <0.20 <0.20 <0.20

Joint Base 02/06/2013 SB 88 0.7 5.8 <0.20 <0.20 <0.20

Joint Base 05/13/2013 SB 91 0.9 5.6 <0.20 <0.20 <0.20

Joint Base 06/24/2013 SB 110 0.8 6.5 <0.20 <0.20 <0.20

Joint Base 07/21/2014 SB 100 0.8 6.1 <0.20 <0.20 <0.20

-- 11/28/2012 SBQ (standard 

reference 

material)

380 2.8 16 <0.20 <0.20 <0.20

-- 04/09/2013 SBQ (standard 

reference 

material)

380 2.6 15 <0.20 <0.20 <0.20
Table 8 79

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Chlorpyrifos

(micrograms 

per 

kilogram)

cisChlordane

(micrograms 

per 

kilogram)

cisNonachlor

(micrograms 

per 

kilogram)

Cyfluthrin

(micrograms 

per 

kilogram)

DCPA 

(Dacthal)

(micrograms 

per 

kilogram)

Desulfinylfipronil

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.20 <0.20 <0.10 <0.20 m <0.20 0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.20 <0.20 <0.10 <0.20 m <0.20 <0.10

Loop 410 01/09/2013 SS <0.20 0.37 0.13 E16.0 m 0.07 t E0.08 n

Loop 410 02/07/2013 SB <0.20 <0.20 <0.10 <0.20 m <0.20 E0.01 bt

Loop 410 02/07/2013 SBQ 

(replicate)

<0.20 0.01 bt <0.10 <0.20 m <0.20 <0.10

Loop 410 04/29/2013 SS E5.5 0.43 E0.14 E7.6 m <0.20 E0.15

Loop 410 05/14/2013 SB <0.20 0.06 t <0.10 E0.07 bmt <0.20 E0.02 bt

Loop 410 05/14/2013 SBQ 

(replicate)

<0.20 E0.08 tm E0.04 bt E2.9 m <0.20 E0.95

Loop 410 05/24/2013 SS E2.3 E0.47 E0.24 E15.7 m <0.20 E1.0

Loop 410 06/25/2013 SB <0.20 E0.02 btm <0.10 E0.08 bmt <0.20 <0.10

Loop 410 06/25/2014 SS E0.07 tm 0.31 0.14 E1.6 m <0.20 0.10

Loop 410 07/22/2014 SB <0.20 <0.20 <0.10 <0.20 m <0.20 <0.10

Loop 410 07/22/2014 SBQ 

(replicate)

<0.20 <0.20 <0.10 <0.20 m <0.20 <0.10

Rodriguez 

Park

11/15/2012 SB <0.20 0.26 <0.10 <0.20 m <0.20 <0.10

Rodriguez 

Park

02/07/2013 SB <0.20 0.18 n 0.06 t <0.20 m <0.20 <0.10

Rodriguez 

Park

04/29/2013 SS <0.20 0.44 E0.09 n E13.4 m <0.20 E0.08 n

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<0.20 0.60 E0.12 E11.9 m <0.20 E0.07 n

Rodriguez 

Park

05/14/2013 SB <0.20 E0.33 E0.13 E1.3 m <0.20 <0.17

Rodriguez 

Park

05/24/2013 SS E1.5 E1.0 E0.56 E25.4 m <0.20 E1.1

Rodriguez 

Park

06/24/2013 SB <0.20 0.38 E0.07 n E0.04 bmt <0.20 <0.10

Rodriguez 

Park

06/25/2014 SS <0.20 0.58 0.28 E1.6 m <0.20 <0.15
80 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Chlorpyrifos

(micrograms 

per 

kilogram)

cisChlordane

(micrograms 

per 

kilogram)

cisNonachlor

(micrograms 

per 

kilogram)

Cyfluthrin

(micrograms 

per 

kilogram)

DCPA 

(Dacthal)

(micrograms 

per 

kilogram)

Desulfinylfipronil

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <0.20 0.38 0.12 <0.20 m <0.20 0.03 bt

Morey Road 11/15/2012 SB <0.20 <0.20 <0.10 <0.20 m <0.20 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.20 0.03 bt 0.01 bt <0.20 m <0.20 <0.10

Morey Road 02/06/2013 SBQ 

(replicate)

<0.20 0.05 t E0.02 bt <0.20 m <0.20 <0.10

Morey Road 04/29/2013 SS <0.20 1.6 E0.55 E1.4 m <0.20 <0.10

Morey Road 05/13/2013 SB <0.20 E0.05 tm E0.04 bt <2.0 m <0.20 E0.06 t

Morey Road 05/24/2013 SS E2.2 E0.69 E0.30 E12.7 m <0.20 <0.34

Morey Road 05/24/2013 SSQ 

(replicate)

E1.3 0.75 E0.30 E11.9 m <0.20 E0.62

Morey Road 06/25/2013 SB <0.20 0.27 E0.21 E2.0 m <0.20 <0.10

Morey Road 06/25/2013 SBQ 

(replicate)

<0.20 0.08 n E0.04 bt <2.0 m <0.20 E0.07 n

Morey Road 06/25/2014 SS <0.20 0.32 0.10 n E1.5 m <0.20 <0.28

Morey Road 07/21/2014 SB <0.20 3.1 0.48 <0.20 m <0.20 <0.10

Joint Base 11/16/2012 SB <0.20 1.2 0.36 <0.55 m <0.20 0.11

Joint Base 11/16/2012 SBQ 

(replicate)

<0.20 0.57 0.17 <0.20 m <0.20 <0.10

Joint Base 02/06/2013 SB <0.20 0.53 0.15 <0.20 m <0.20 <0.10

Joint Base 05/13/2013 SB <0.20 1.3 E0.49 E0.22 m <0.20 <0.10

Joint Base 06/24/2013 SB <0.20 2.6 E1.1 <2.0 m <0.20 E0.30

Joint Base 07/21/2014 SB <0.20 2.0 0.34 <0.20 m <0.20 0.02 bt

-- 11/28/2012 SBQ (standard 

reference 

material)

<0.20 <0.20 <0.10 <0.20 m <0.20 <0.10

-- 04/09/2013 SBQ (standard 

reference 

material)

<0.20 0.04 t E0.03 bt <0.20 m <0.20 <0.10
Table 8 81

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Dieldrin

(micrograms 

per 

kilogram)

Endosulfan 

sulfate

(micrograms 

per 

kilogram)

Fipronil 

sulfide

(micrograms 

per 

kilogram)

Fipronil

(micrograms 

per 

kilogram)

Hexachlorobenzene

(micrograms 

per 

kilogram)

lambdaCyhalothrin

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.40 <0.10 -- <0.10 1.7

Loop 410 01/09/2013 SS <0.10 <0.40 <0.10 -- 0.22 E2.9

Loop 410 02/07/2013 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Loop 410 02/07/2013 SBQ 

(replicate)

<0.10 <0.40 <0.10 -- <0.10 <0.20

Loop 410 04/29/2013 SS <0.10 <0.40 E0.04 bt -- <0.10 E1.9

Loop 410 05/14/2013 SB <0.10 <0.40 E0.02 bt -- <0.10 <0.20

Loop 410 05/14/2013 SBQ 

(replicate)

<0.10 <0.40 E0.05 t -- <0.10 <0.20

Loop 410 05/24/2013 SS E0.11 <0.40 E0.08 n -- <0.10 E4.5

Loop 410 06/25/2013 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Loop 410 06/25/2014 SS E0.21 <0.40 <0.10 <0.10 m <38 1.1

Loop 410 07/22/2014 SB <0.10 <0.40 <0.10 <0.10 m <0.10 <0.20

Loop 410 07/22/2014 SBQ 

(replicate)

<0.10 <0.40 <0.10 <0.10 m <0.10 <0.20

Rodriguez 

Park

11/15/2012 SB E0.15 <0.40 <0.10 -- <0.10 <0.20

Rodriguez 

Park

02/07/2013 SB E0.06 t <0.40 E0.01 b -- <0.10 <0.20

Rodriguez 

Park

04/29/2013 SS <0.10 <0.40 E0.05 t -- <0.10 E2.1

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<0.10 <0.40 E0.04 t -- <0.10 E2.6

Rodriguez 

Park

05/14/2013 SB E0.26 <0.40 E0.02 bt -- <0.10 <0.20

Rodriguez 

Park

05/24/2013 SS E0.44 <0.40 0.09 n <0.10 m <0.10 E8.2

Rodriguez 

Park

06/24/2013 SB E0.21 <0.40 <0.10 -- <0.10 <0.20

Rodriguez 

Park

06/25/2014 SS E0.47 <0.40 <0.10 <0.10 m <110 0.43
82 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Dieldrin

(micrograms 

per 

kilogram)

Endosulfan 

sulfate

(micrograms 

per 

kilogram)

Fipronil 

sulfide

(micrograms 

per 

kilogram)

Fipronil

(micrograms 

per 

kilogram)

Hexachlorobenzene

(micrograms 

per 

kilogram)

lambdaCyhalothrin

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 0.11 <0.40 0.01 bt <0.42 vm <0.10 <0.20

Morey Road 11/15/2012 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Morey Road 02/06/2013 SBQ 

(replicate)

<0.10 <0.40 <0.10 -- <0.10 <0.20

Morey Road 04/29/2013 SS <0.10 <0.40 <0.10 -- <0.10 E0.10 t

Morey Road 05/13/2013 SB <0.10 <0.40 E0.01 b -- <0.10 <0.20

Morey Road 05/24/2013 SS E0.28 <0.40 <0.10 -- <0.10 E3.2

Morey Road 05/24/2013 SSQ 

(replicate)

E0.46 <0.40 E0.14 E6.9 m <0.10 E3.4

Morey Road 06/25/2013 SB E0.01 bt <0.40 E0.01 bt -- <0.10 <0.20

Morey Road 06/25/2013 SBQ 

(replicate)

E0.01 bt <0.40 E0.01 bt -- <0.10 <0.20

Morey Road 06/25/2014 SS <0.10 <0.40 <0.16 <0.10 m <160 0.43

Morey Road 07/21/2014 SB <0.10 <0.40 <0.10 <0.41 vm <0.10 <0.20

Joint Base 11/16/2012 SB 0.13 <0.40 <0.10 -- <0.10 <0.20

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <0.40 <0.10 -- <0.10 <0.20

Joint Base 02/06/2013 SB <0.10 <0.40 <0.10 -- <0.10 <0.20

Joint Base 05/13/2013 SB <0.10 <0.40 E0.03 bt -- <0.10 E0.21

Joint Base 06/24/2013 SB E0.10 n <0.40 E0.05 t -- <0.10 <0.20

Joint Base 07/21/2014 SB <0.10 <0.40 0.02 bt <0.42 vm <0.98 <0.20

-- 11/28/2012 SBQ (standard 

reference 

material)

<0.10 <0.40 <0.10 -- 6.5 <0.20

-- 04/09/2013 SBQ (standard 

reference 

material)

<0.10 <0.40 <0.10 -- 2.9 <0.20
Table 8 83

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Oxychlordane

(micrograms 

per 

kilogram)

Oxyfluorfen

(micrograms 

per 

kilogram)

p,p'-DDD

(micrograms 

per 

kilogram)

p,p’-DDE

(micrograms 

per 

kilogram)

p,p’-DDT

(micrograms 

per 

kilogram)

Pendimethalin

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 11/15/2012 SBQ 

(replicate)

<1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 01/09/2013 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 02/07/2013 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 02/07/2013 SBQ 

(replicate)

<1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 04/29/2013 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 05/14/2013 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 05/14/2013 SBQ 

(replicate)

<1.0 <4.0 <2.0 h <1.0 h <4.0 h <1.0

Loop 410 05/24/2013 SS <1.0 <4.0 <2.0 h <1.0 h <4.0 h <1.0

Loop 410 06/25/2013 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 06/25/2014 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 07/22/2014 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Loop 410 07/22/2014 SBQ 

(replicate)

<1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Rodriguez 

Park

11/15/2012 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Rodriguez 

Park

02/07/2013 SB <1.0 <4.0 <2.0 0.65 n <4.0 <1.0

Rodriguez 

Park

04/29/2013 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Rodriguez 

Park

05/14/2013 SB <1.0 <4.0 <2.0 h E0.02 b E1.5 t <1.0

Rodriguez 

Park

05/24/2013 SS <1.0 <4.0 <2.0 h 0.13 bt <4.0 h --

Rodriguez 

Park

06/24/2013 SB <1.0 <4.0 <2.0 E0.51 n E0.38 bt <1.0

Rodriguez 

Park

06/25/2014 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0
84 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Oxychlordane

(micrograms 

per 

kilogram)

Oxyfluorfen

(micrograms 

per 

kilogram)

p,p'-DDD

(micrograms 

per 

kilogram)

p,p’-DDE

(micrograms 

per 

kilogram)

p,p’-DDT

(micrograms 

per 

kilogram)

Pendimethalin

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Morey Road 11/15/2012 SB <1.0 <4.0 <2.0 0.63 n <4.0 <1.0

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <1.0 <4.0 <2.0 2.2 <4.0 <1.0

Morey Road 02/06/2013 SBQ 

(replicate)

<1.0 <4.0 <2.0 1.2 <4.0 <1.0

Morey Road 04/29/2013 SS <1.0 <4.0 <2.0 2.6 <4.0 <1.0

Morey Road 05/13/2013 SB <1.0 <4.0 <2.0 h E0.60 n E2.6 n <1.0

Morey Road 05/24/2013 SS <1.0 <4.0 <2.0 h E0.28 bt <4.0 <1.0

Morey Road 05/24/2013 SSQ 

(replicate)

<1.0 <4.0 <2.0 h E0.22 bt E35.8 <1.0

Morey Road 06/25/2013 SB <1.0 <4.0 <2.0 h E0.12 bt E1.5 t <1.0

Morey Road 06/25/2013 SBQ 

(replicate)

<1.0 <4.0 <2.0 h E0.31 bn E4.7 <1.0

Morey Road 06/25/2014 SS <1.0 <4.0 <2.0 <1.0 <4.0 <1.0

Morey Road 07/21/2014 SB <1.0 <4.0 0.39 bt <1.0 <4.0 <1.0

Joint Base 11/16/2012 SB <1.0 <4.0 9.6 13.7 <4.0 <1.0

Joint Base 11/16/2012 SBQ 

(replicate)

<1.0 <4.0 6.2 5.8 <4.0 <1.0

Joint Base 02/06/2013 SB <1.0 <4.0 <2.0 9.6 <4.0 <1.0

Joint Base 05/13/2013 SB <1.0 <4.0 <2.0 20.8 E118 <1.0

Joint Base 06/24/2013 SB <1.0 <4.0 E58.3 E10.4 E130 <1.0

Joint Base 07/21/2014 SB <1.0 <4.0 4.4 19.0 2.9 n <1.0

-- 11/28/2012 SBQ (standard 

reference 

material)

<1.0 <4.0 <2.0 <1.0 <4.0 <1.0

-- 04/09/2013 SBQ (standard 

reference 

material)

<1.0 <4.0 <2.0 0.14 bt <4.0 <1.0
Table 8 85

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Pentachloroanisole

(micrograms 

per 

kilogram)

Pentachloronitrobenzene

(micrograms 

per 

kilogram)

Tefluthrin

(micrograms 

per 

kilogram)

Tetradifon

(micrograms 

per 

kilogram)

transChlordane

(micrograms 

per 

kilogram)

transNonachlor

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Loop 410 01/09/2013 SS 0.12 <0.10 <0.50 <0.20 0.18 n 0.32

Loop 410 02/07/2013 SB <0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Loop 410 02/07/2013 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Loop 410 04/29/2013 SS <0.10 <0.10 <0.50 <0.20 E0.36 E0.52

Loop 410 05/14/2013 SB <0.10 <0.10 <0.50 <0.20 <0.20 M

Loop 410 05/14/2013 SBQ 

(replicate)

0.01 bt <0.10 <0.50 <0.20 E0.03 bt E0.11

Loop 410 05/24/2013 SS 0.03 bt <0.10 <0.50 <0.20 E0.25 E0.58

Loop 410 06/25/2013 SB <0.10 <0.10 <0.50 <0.20 <0.20 E0.03 bt

Loop 410 06/25/2014 SS <38 <38 <0.50 <0.20 0.20 0.33

Loop 410 07/22/2014 SB <0.10 <0.10 E0.04 t <0.20 E0.10 n E0.10 n

Loop 410 07/22/2014 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Rodriguez 

Park

11/15/2012 SB <0.10 <0.10 <0.50 <0.20 0.25 0.18

Rodriguez 

Park

02/07/2013 SB <0.10 <0.10 <0.50 <0.20 0.23 0.16

Rodriguez 

Park

04/29/2013 SS <0.10 <0.10 <0.50 <0.20 E0.39 E0.36

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 E0.53 E0.53

Rodriguez 

Park

05/14/2013 SB 0.01 bt <0.10 <0.50 <0.20 E0.48 E0.36

Rodriguez 

Park

05/24/2013 SS 0.02 bt <0.10 <0.50 <0.20 E0.59 E1.4

Rodriguez 

Park

06/24/2013 SB <0.10 <0.10 <0.50 <0.20 E0.42 E0.25

Rodriguez 

Park

06/25/2014 SS <110 <110 E0.18 t <0.20 0.43 0.71
86 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Pentachloroanisole

(micrograms 

per 

kilogram)

Pentachloronitrobenzene

(micrograms 

per 

kilogram)

Tefluthrin

(micrograms 

per 

kilogram)

Tetradifon

(micrograms 

per 

kilogram)

transChlordane

(micrograms 

per 

kilogram)

transNonachlor

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <0.10 <0.10 <0.50 <0.20 0.31 0.31

Morey Road 11/15/2012 SB <0.10 <0.10 <0.50 <0.20 <0.20 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.10 <0.10 <0.50 <0.20 0.02 bt 0.02 bt

Morey Road 02/06/2013 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 E0.04 bt E0.05 n

Morey Road 04/29/2013 SS <0.10 <0.10 <0.50 <0.20 E1.2 E2.4

Morey Road 05/13/2013 SB <0.10 <0.10 <0.50 <0.20 E0.03 bt E0.06 n

Morey Road 05/24/2013 SS 0.03 bt <0.10 <0.50 -- E0.46 E0.71

Morey Road 05/24/2013 SSQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 0.47 E0.69

Morey Road 06/25/2013 SB <0.10 <0.10 <0.50 -- 0.18 n E0.34

Morey Road 06/25/2013 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 0.05 t E0.09 n

Morey Road 06/25/2014 SS <160 <160 <0.50 <0.20 0.22 0.33

Morey Road 07/21/2014 SB <0.10 <0.10 <0.50 <0.20 2.9 1.9

Joint Base 11/16/2012 SB <0.10 <0.10 <0.50 <0.20 0.76 0.86

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <0.10 <0.50 <0.20 0.38 0.41

Joint Base 02/06/2013 SB <0.10 <0.10 <0.50 <0.20 0.32 0.34

Joint Base 05/13/2013 SB <0.10 <0.10 <0.50 <0.20 E0.77 E1.3

Joint Base 06/24/2013 SB <0.10 <0.10 <0.50 <0.20 1.9 E2.5

Joint Base 07/21/2014 SB <0.10 <0.10 <0.50 <0.20 1.4 1.1

-- 11/28/2012 SBQ (standard 

reference 

material)

0.12 <0.10 <0.50 2.9 <0.20 <0.10

-- 04/09/2013 SBQ (standard 

reference 

material)

0.06 n <0.10 <0.50 1.6 E0.05 t <0.10
Table 8 87

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Trifluralin

(micrograms 

per 

kilogram)

Total 

PCB

(micrograms 

per 

kilogram)1

PCB 

congener 101

(micrograms 

per 

kilogram)

PCB 

congener 110

(micrograms 

per 

kilogram)

PCB 

congener 118

(micrograms 

per 

kilogram)

PCB 

congener 138

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 01/09/2013 SS <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 02/07/2013 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 02/07/2013 SBQ 

(replicate)

<0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 04/29/2013 SS <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 05/14/2013 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 05/14/2013 SBQ 

(replicate)

<0.20 E0.4 <1.0 <1.0 <0.10 <0.10

Loop 410 05/24/2013 SS <0.20 E0.9 <1.0 <1.0 <0.10 0.12

Loop 410 06/25/2013 SB <0.20 E0.4 <1.0 <1.0 <0.10 <0.10

Loop 410 06/25/2014 SS <0.20 E1.0 <1.0 <1.0 <0.11 0.09 n

Loop 410 07/22/2014 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Loop 410 07/22/2014 SBQ 

(replicate)

<0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

11/15/2012 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

02/07/2013 SB <0.20 E0.4 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

04/29/2013 SS <0.20 E1.0 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<0.20 E0.9 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

05/14/2013 SB <0.20 E0.4 <1.0 <1.0 <0.10 0.05 t

Rodriguez 

Park

05/24/2013 SS <0.20 E1.2 <1.0 <1.0 <0.10 0.14

Rodriguez 

Park

06/24/2013 SB <0.20 E0.8 <1.0 <1.0 <0.10 <0.10

Rodriguez 

Park

06/25/2014 SS <0.20 E2.2 <1.0 <1.0 0.38 <0.10
88 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

Trifluralin

(micrograms 

per 

kilogram)

Total 

PCB

(micrograms 

per 

kilogram)1

PCB 

congener 101

(micrograms 

per 

kilogram)

PCB 

congener 110

(micrograms 

per 

kilogram)

PCB 

congener 118

(micrograms 

per 

kilogram)

PCB 

congener 138

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <0.20 E1.4 <1.0 <1.0 <0.10 <0.10

Morey Road 11/15/2012 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.20 <9.2 <1.0 <1.0 <0.10 <0.10

Morey Road 02/06/2013 SBQ 

(replicate)

<0.20 E0.2 <1.0 <1.0 <0.10 <0.10

Morey Road 04/29/2013 SS <0.20 E1.7 <1.0 <1.0 <0.10 <0.10

Morey Road 05/13/2013 SB <0.20 E0.2 <1.0 <1.0 <0.10 0.03 bt

Morey Road 05/24/2013 SS <0.20 E1.2 <1.0 <1.0 <0.10 0.15

Morey Road 05/24/2013 SSQ 

(replicate)

<0.20 E1.9 E0.12 bt E0.65 n <0.10 E0.17

Morey Road 06/25/2013 SB <0.20 E0.2 <1.0 <1.0 <0.10 E0.03 bt

Morey Road 06/25/2013 SBQ 

(replicate)

<0.20 E0.2 <1.0 <1.0 <0.10 <0.10

Morey Road 06/25/2014 SS <0.20 E2.1 <1.0 <1.0 <0.10 <0.10

Morey Road 07/21/2014 SB <0.20 <9.1 <1.0 <1.0 <0.10 <0.10

Joint Base 11/16/2012 SB <0.20 E4.6 <1.0 <1.0 E0.18 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.20 E3.8 <1.0 <1.0 <0.10 <0.10

Joint Base 02/06/2013 SB <0.20 E2.2 <1.0 <1.0 <0.10 <0.10

Joint Base 05/13/2013 SB <0.20 E7.5 <1.0 1.2 <0.10 1.2

Joint Base 06/24/2013 SB <0.20 E8.7 <1.0 E2.7 E0.25 E0.58

Joint Base 07/21/2014 SB <0.20 E7.0 <1.0 <5.3 0.31 <0.67

-- 11/28/2012 SBQ (standard 

reference 

material)

<0.20 E14.5 <1.0 <1.0 1.5 1.7

-- 04/09/2013 SBQ (standard 

reference 

material)

<0.20 E9.8 0.43 t 1.7 E0.73 1.3
Table 8 89

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 146

(micrograms 

per 

kilogram)

PCB 

congener 149

(micrograms 

per 

kilogram)

PCB 

congener 151

(micrograms 

per 

kilogram)

PCB 

congener 170

(micrograms 

per 

kilogram)

PCB 

congener 174

(micrograms 

per 

kilogram)

PCB 

congener 177

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 01/09/2013 SS <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 02/07/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 02/07/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 04/29/2013 SS <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 05/14/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 05/14/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 0.03 bt <0.10 <0.10

Loop 410 05/24/2013 SS 0.03 bt <1.0 <0.10 0.06 t 0.07 n 0.06 t

Loop 410 06/25/2013 SB <0.10 <1.0 <0.10 E0.03 bt <0.10 <0.10

Loop 410 06/25/2014 SS 0.02 bt <1.0 <0.10 0.10 <0.10 <0.10

Loop 410 07/22/2014 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Loop 410 07/22/2014 SBQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Rodriguez 

Park

11/15/2012 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Rodriguez 

Park

02/07/2013 SB <0.10 <1.0 <0.10 0.02 bt <0.10 <0.10

Rodriguez 

Park

04/29/2013 SS <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Rodriguez 

Park

05/14/2013 SB 0.01 bt <1.0 0.01 bt 0.03 bt 0.02 bt 0.02 bt

Rodriguez 

Park

05/24/2013 SS 0.03 bt 0.12 bt 0.05 t 0.07 n 0.08 n 0.06 n

Rodriguez 

Park

06/24/2013 SB <0.10 <1.0 E0.04 bt E0.06 t E0.05 t E0.05 t

Rodriguez 

Park

06/25/2014 SS 0.02 bt <1.0 <0.10 0.21 0.14 <0.10
90 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 146

(micrograms 

per 

kilogram)

PCB 

congener 149

(micrograms 

per 

kilogram)

PCB 

congener 151

(micrograms 

per 

kilogram)

PCB 

congener 170

(micrograms 

per 

kilogram)

PCB 

congener 174

(micrograms 

per 

kilogram)

PCB 

congener 177

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <0.10 <1.0 <0.10 0.09 n 0.06 n <0.10

Morey Road 11/15/2012 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Morey Road 02/06/2013 SBQ 

(replicate)

<0.10 <1.0 <0.10 0.02 bt <0.10 <0.10

Morey Road 04/29/2013 SS <0.10 <1.0 <0.10 0.16 <0.10 <0.10

Morey Road 05/13/2013 SB 0.01 bt <1.0 <0.10 0.01 bt 0.02 bt 0.01 bt

Morey Road 05/24/2013 SS 0.04 bt 0.13 bt 0.05 t 0.06 t 0.08 n 0.06 n

Morey Road 05/24/2013 SSQ 

(replicate)

0.03 bt E0.14 bt 0.05 t 0.07 t 0.08 n 0.06 n

Morey Road 06/25/2013 SB 0.01 bt <1.0 <0.10 0.01 bt <0.10 0.01 bt

Morey Road 06/25/2013 SBQ 

(replicate)

0.01 bt <1.0 <0.10 0.01 bt 0.02 bt 0.01 bt

Morey Road 06/25/2014 SS <0.10 <1.0 <0.10 0.20 <0.10 <0.10

Morey Road 07/21/2014 SB <0.10 <1.0 <0.10 <0.10 <0.10 <0.10

Joint Base 11/16/2012 SB <0.12 <1.0 E0.14 E0.62 <0.10 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <1.0 <0.10 E0.30 <0.10 <0.10

Joint Base 02/06/2013 SB 0.12 <1.0 <0.10 0.23 0.13 0.05 t

Joint Base 05/13/2013 SB E0.15 E0.55 n 0.11 0.49 E0.31 0.21

Joint Base 06/24/2013 SB 0.14 E0.54 n E0.19 0.55 0.35 0.26

Joint Base 07/21/2014 SB 0.21 0.65 n 0.22 0.69 0.37 0.29

-- 11/28/2012 SBQ (standard 

reference 

material)

0.58 0.52 n 0.36 0.87 0.57 0.49

-- 04/09/2013 SBQ (standard 

reference 

material)

0.18 0.93 n 0.22 0.36 E0.25 0.20
Table 8 91

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 180

(micrograms 

per 

kilogram)

PCB 

congener 183

(micrograms 

per 

kilogram)

PCB 

congener 187

(micrograms 

per 

kilogram)

PCB 

congener 194

(micrograms 

per 

kilogram)

PCB 

congener 206

(micrograms 

per 

kilogram)

PCB 

congener 49

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 01/09/2013 SS <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 02/07/2013 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 02/07/2013 SBQ 

(replicate)

<0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 04/29/2013 SS <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 05/14/2013 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 05/14/2013 SBQ 

(replicate)

0.02 bt <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 05/24/2013 SS 0.05 n 0.04 bt 0.05 t 0.03 bt 0.04 n <2.0 m

Loop 410 06/25/2013 SB E0.03 bt <0.10 E0.03 bt E0.03 bt E0.01 bt <2.0 m

Loop 410 06/25/2014 SS <0.10 <0.10 0.06 n <0.10 0.04 n <2.0 m

Loop 410 07/22/2014 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Loop 410 07/22/2014 SBQ 

(replicate)

<0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Rodriguez 

Park

11/15/2012 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Rodriguez 

Park

02/07/2013 SB 0.04 t 0.01 bt 0.02 bt <0.10 0.04 bt <2.0 m

Rodriguez 

Park

04/29/2013 SS 0.08 n <0.10 <0.10 0.06 n <0.10 <2.0 m

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

0.08 n <0.10 <0.10 0.05 t <0.10 <2.0 m

Rodriguez 

Park

05/14/2013 SB 0.04 bt 0.01 bt 0.03 bt 0.01 bt 0.01 bt <2.0 m

Rodriguez 

Park

05/24/2013 SS 0.09 n 0.04 t 0.07 n 0.03 bt 0.04 n <2.0 m

Rodriguez 

Park

06/24/2013 SB E0.07 n E0.04 t E0.05 n E0.04 t E0.02 bt <2.0 m

Rodriguez 

Park

06/25/2014 SS E0.28 v <0.10 0.16 <0.10 0.09 n <2.0 m
92 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 180

(micrograms 

per 

kilogram)

PCB 

congener 183

(micrograms 

per 

kilogram)

PCB 

congener 187

(micrograms 

per 

kilogram)

PCB 

congener 194

(micrograms 

per 

kilogram)

PCB 

congener 206

(micrograms 

per 

kilogram)

PCB 

congener 49

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB 0.12 <0.10 0.07 n <0.10 <0.10 <2.0 m

Morey Road 11/15/2012 SB <0.10 <0.10 <0.10 <0.10 <0.10 <2.0 m

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB 0.01 bt <0.10 <0.10 <0.10 <0.10 <2.0 m

Morey Road 02/06/2013 SBQ 

(replicate)

0.02 bt <0.10 0.01 bt 0.01 bt 0.01 bt <2.0 m

Morey Road 04/29/2013 SS 0.19 <0.10 0.07 n 0.11 0.08 n <2.0 m

Morey Road 05/13/2013 SB 0.02 bt 0.01 bt 0.01 bt 0.01 bt <0.10 <2.0 m

Morey Road 05/24/2013 SS 0.09 n 0.04 t 0.07 n 0.04 bt 0.04 n <2.0 m

Morey Road 05/24/2013 SSQ 

(replicate)

0.08 n 0.05 t 0.06 n 0.03 bt 0.04 bt <2.0 m

Morey Road 06/25/2013 SB 0.01 bt 0.01 bt 0.01 bt 0.01 bt 0.01 bt <2.0 m

Morey Road 06/25/2013 SBQ 

(replicate)

0.02 bt 0.01 bt 0.01 bt 0.01 bt 0.01 bt <2.0 m

Morey Road 06/25/2014 SS E0.24 v <0.10 0.14 <0.10 0.10 n <2.0 m

Morey Road 07/21/2014 SB 0.04 t <0.10 <0.10 <0.10 <0.10 <2.0 m

Joint Base 11/16/2012 SB E0.96 E0.18 E0.41 <0.10 <0.10 <2.0 m

Joint Base 11/16/2012 SBQ 

(replicate)

E0.44 <0.10 E0.18 <0.10 <0.10 <2.0 m

Joint Base 02/06/2013 SB 0.45 0.09 n 0.18 0.05 t 0.09 n <2.0 m

Joint Base 05/13/2013 SB E0.85 E0.19 E0.37 E0.21 E0.14 <2.0 m

Joint Base 06/24/2013 SB 0.83 0.20 0.42 0.17 0.11 <2.0 m

Joint Base 07/21/2014 SB 1.1 0.21 0.51 0.22 0.18 <2.0 m

-- 11/28/2012 SBQ (standard 

reference 

material)

1.5 0.56 0.81 0.52 1.2 <2.0 m

-- 04/09/2013 SBQ (standard 

reference 

material)

E0.73 E0.17 E0.44 E0.23 E0.54 <2.0 m
Table 8 93

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 52

(micrograms 

per 

kilogram)

PCB 

congener 70

(micrograms 

per 

kilogram)

1,2-Bis(2,4,6-

tribromophenoxy)

ethane

(micrograms 

per 

kilogram)

PBDE 

congener 100

(micrograms 

per 

kilogram)

PBDE 

congener 138

(micrograms 

per 

kilogram)

PBDE 

congener 153

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <1.0 m <2.0 <0.10 <0.11 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<1.0 m <2.0 <0.10 <0.10 <0.10 <0.10

Loop 410 01/09/2013 SS <1.0 m <2.0 E0.92 E6.2 v 0.63 2.9

Loop 410 02/07/2013 SB <1.0 m <2.0 <0.10 <0.11 <0.10 0.05 n

Loop 410 02/07/2013 SBQ 

(replicate)

<1.0 m <2.0 E0.15 E0.08 n <0.10 E0.08 n

Loop 410 04/29/2013 SS <1.0 m <2.0 E1.8 E1.8 E0.23 E1.3

Loop 410 05/14/2013 SB <1.0 m <2.0 E0.22 E0.09 n <0.10 E0.06 n

Loop 410 05/14/2013 SBQ 

(replicate)

<1.0 m <2.0 E0.09 n <0.16 <0.10 E0.07 n

Loop 410 05/24/2013 SS <1.0 m <2.0 E0.42 E1.1v <0.27 E0.97

Loop 410 06/25/2013 SB <1.0 m <2.0 <0.10 <0.14 <0.10 E0.04 bt

Loop 410 06/25/2014 SS <1.0 m <2.0 E0.13 E0.60 v E0.10 n 0.57

Loop 410 07/22/2014 SB <1.0 m <2.0 <0.10 0.13 <0.10 <0.10

Loop 410 07/22/2014 SBQ 

(replicate)

<1.0 m <2.0 <0.10 <0.12 <0.10 <0.10

Rodriguez 

Park

11/15/2012 SB <1.0 m <2.0 <0.10 <0.14 <0.10 <0.10

Rodriguez 

Park

02/07/2013 SB <1.0 m <2.0 E0.06 n <0.10 <0.10 0.02 bt

Rodriguez 

Park

04/29/2013 SS <1.0 m <2.0 E0.74 E0.49 <0.10 E0.56

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

<1.0 m <2.0 E0.43 E0.43 <0.10 E0.51

Rodriguez 

Park

05/14/2013 SB <1.0 m <2.0 E0.04 bt <0.11 <0.10 E0.07 n

Rodriguez 

Park

05/24/2013 SS <1.0 m <2.0 E0.54 E0.58 v E0.15 E0.48

Rodriguez 

Park

06/24/2013 SB <1.0 m <2.0 E0.05 n <0.19 E0.02 bt E0.07 n

Rodriguez 

Park

06/25/2014 SS <1.0 m <2.0 <0.34 E1.4 v <0.10 0.85
94 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PCB 

congener 52

(micrograms 

per 

kilogram)

PCB 

congener 70

(micrograms 

per 

kilogram)

1,2-Bis(2,4,6-

tribromophenoxy)

ethane

(micrograms 

per 

kilogram)

PBDE 

congener 100

(micrograms 

per 

kilogram)

PBDE 

congener 138

(micrograms 

per 

kilogram)

PBDE 

congener 153

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <1.0 m <2.0 <0.10 <0.10 <0.10 <0.10

Morey Road 11/15/2012 SB <1.0 m <2.0 <0.10 <0.10 <0.10 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <1.0 m <2.0 <0.10 <0.10 <0.10 <0.10

Morey Road 02/06/2013 SBQ 

(replicate)

<1.0 m <2.0 E0.05 n E0.08 n <0.10 E0.05 n

Morey Road 04/29/2013 SS <1.0 m <2.0 E0.61 E0.51 <0.10 E0.48

Morey Road 05/13/2013 SB <1.0 m <2.0 <0.10 <0.10 <0.10 E0.02 bt

Morey Road 05/24/2013 SS <1.0 m <2.0 E2.1 E0.37 v <0.10 E0.25

Morey Road 05/24/2013 SSQ 

(replicate)

<1.0 m <2.0 <0.20 E0.52 v <0.10 E0.38

Morey Road 06/25/2013 SB <1.0 m <2.0 <0.10 <0.10 <0.10 E0.03 bt

Morey Road 06/25/2013 SBQ 

(replicate)

<1.0 m <2.0 <0.10 <0.10 <0.10 E0.03 bt

Morey Road 06/25/2014 SS <1.0 m <2.0 E0.24 E0.56 v <0.10 0.41

Morey Road 07/21/2014 SB <1.0 m <2.0 <0.10 0.06 n <0.10 <0.10

Joint Base 11/16/2012 SB <1.0 m <2.0 <0.10 <0.20 <0.10 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<1.0 m <2.0 <0.10 <0.13 <0.10 <0.10

Joint Base 02/06/2013 SB <1.0 m <2.0 <0.10 <0.18 <0.10 0.08 n

Joint Base 05/13/2013 SB <1.0 m <2.0 E0.31 E0.28 <0.10 E0.17

Joint Base 06/24/2013 SB <1.0 m <2.0 E0.26 E0.33 v <0.10 E0.19

Joint Base 07/21/2014 SB <1.0 m <2.0 <0.14 0.16 <0.10 <0.10

-- 11/28/2012 SBQ 

(standard 

reference 

material)

<1.0 m <2.0 <0.10 <0.41 <0.10 <0.10

-- 04/09/2013 SBQ 

(standard 

reference 

material)

<1.0 m <2.0 E0.17 E0.18 <0.10 E0.08 n
Table 8 95

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PBDE 

congener 154

(micrograms 

per 

kilogram)

PBDE 

congener 183

(micrograms 

per 

kilogram)

PBDE 

congener 47

(micrograms 

per kilogram)

PBDE 

congener 66

(micrograms 

per 

kilogram)

PBDE 

congener 71

(micrograms 

per 

kilogram)

PBDE 

congener 85

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.10 <0.10 <0.90 <0.10 <0.10 <0.10

Loop 410 11/15/2012 SBQ 

(replicate)

<0.10 <0.10 <0.88 <0.10 <0.10 <0.10

Loop 410 01/09/2013 SS 3.1 5.2 E19.8 v 0.82 <0.10 1.5

Loop 410 02/07/2013 SB 0.02 bt <0.10 <0.72 <0.10 <0.10 <0.10

Loop 410 02/07/2013 SBQ 

(replicate)

E0.04 t <0.10 E0.57 v <0.10 <0.10 E0.01 btm

Loop 410 04/29/2013 SS E0.89 <0.10 E6.8 v E0.34 <0.10 E0.62

Loop 410 05/14/2013 SB E0.03 bt <0.10 E0.64 v <0.10 <0.10 E0.01 btm

Loop 410 05/14/2013 SBQ 

(replicate)

E0.04 t <0.50 <0.76 <0.10 <0.10 <0.10

Loop 410 05/24/2013 SS E0.70 E0.47 <3.3 E0.07 n <0.10 E0.46

Loop 410 06/25/2013 SB E0.03 bt <0.10 <1.1 <0.10 <0.10 <0.10

Loop 410 06/25/2014 SS 0.41 E0.20 E1.9 v 0.10 <0.10 E0.19

Loop 410 07/22/2014 SB <0.10 <0.10 <0.50 <0.10 <0.10 <0.10

Loop 410 07/22/2014 SBQ 

(replicate)

<0.10 <0.10 <0.44 <0.10 <0.10 <0.10

Rodriguez 

Park

11/15/2012 SB <0.10 <0.10 <1.5 <0.10 <0.10 <0.10

Rodriguez 

Park

02/07/2013 SB 0.02 bt <0.10 <0.28 <0.10 <0.10 <0.10

Rodriguez 

Park

04/29/2013 SS E0.35 <0.10 E2.4 v E0.03 bt <0.10 E0.20

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

E0.30 <0.10 E2.0 E0.02 bt <0.10 E0.15

Rodriguez 

Park

05/14/2013 SB E0.06 n <0.50 <0.47 <0.10 <0.10 E0.04 btm

Rodriguez 

Park

05/24/2013 SS E0.32 <0.10 <2.2 0.04 t <0.10 E0.24

Rodriguez 

Park

06/24/2013 SB E0.06 n <0.10 <1.5 E0.02 bt <0.10 <0.10

Rodriguez 

Park

06/25/2014 SS 0.73 <0.10 E5.8 v <0.10 <0.10 E0.43
96 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PBDE 

congener 154

(micrograms 

per 

kilogram)

PBDE 

congener 183

(micrograms 

per 

kilogram)

PBDE 

congener 47

(micrograms 

per kilogram)

PBDE 

congener 66

(micrograms 

per 

kilogram)

PBDE 

congener 71

(micrograms 

per 

kilogram)

PBDE 

congener 85

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB <0.10 <0.10 E0.48 v <0.10 <0.10 <0.10

Morey Road 11/15/2012 SB <0.10 <0.10 <1.5 <0.10 <0.10 <0.10

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.10 <0.10 <0.21 <0.10 <0.10 <0.10

Morey Road 02/06/2013 SBQ 

(replicate)

E0.03 bt <0.10 <0.37 E0.01 bt <0.10 <0.10

Morey Road 04/29/2013 SS E0.33 <0.10 E2.9 v E0.03 bt <0.10 E0.19

Morey Road 05/13/2013 SB <0.10 <0.50 <0.27 <0.10 <0.10 E0.02 btm

Morey Road 05/24/2013 SS E0.18 <0.50 <1.4 E0.01 bt <0.10 <0.12

Morey Road 05/24/2013 SSQ 

(replicate)

E0.27 <0.50 <1.6 0.02 bt <0.10 <0.22

Morey Road 06/25/2013 SB <0.10 <0.50 <0.23 <0.10 <0.10 <0.10

Morey Road 06/25/2013 SBQ 

(replicate)

E0.25 <0.50 <0.20 <0.10 <0.10 <0.10

Morey Road 06/25/2014 SS <16.4 E0.26 E2.1 v <0.10 <0.10 E0.22

Morey Road 07/21/2014 SB <0.27 <0.10 <0.40 <0.10 <0.10 <0.10

Joint Base 11/16/2012 SB <0.10 <0.10 <1.5 <0.10 <0.10 <0.10

Joint Base 11/16/2012 SBQ 

(replicate)

<0.10 <0.10 <1.0 <0.10 <0.10 <0.10

Joint Base 02/06/2013 SB 0.03 bt <0.10 <1.3 <0.10 <0.10 0.04 t

Joint Base 05/13/2013 SB E0.11 <0.10 E1.6 v E0.01 bt <0.10 E0.07 nm

Joint Base 06/24/2013 SB E0.17 <0.50 <1.1 E0.01 bt <0.10 <0.10

Joint Base 07/21/2014 SB 0.37 <0.10 E0.77 v 0.03 bt <0.10 <0.10

-- 11/28/2012 SBQ 

(standard 

reference 

material)

<0.10 <0.10 4.0 <0.10 <0.10 <0.10

-- 04/09/2013 SBQ 

(standard 

reference 

material)

E0.04 t <0.10 E1.7 v E0.03 bt <0.10 E0.15
Table 8 97

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PBDE 

congener 99

(micrograms 

per 

kilogram)

Dechlorane 

plus

(micrograms 

per 

kilogram)

Methyl 

triclosan

(micrograms 

per 

kilogram)

Octachlorostyrene

(micrograms 

per 

kilogram)

Pentabromotoluene

(micrograms 

per 

kilogram)

Triclosan

(micrograms 

per 

kilogram)

Loop 410 11/15/2012 SB <0.35 <1.0 <6.0 <1.0 <1.0 --

Loop 410 11/15/2012 SBQ 

(replicate)

<0.27 <1.0 <6.0 <1.0 <1.0 --

Loop 410 01/09/2013 SS E23.8 v 1.3 <6.0 <1.0 <1.0 --

Loop 410 02/07/2013 SB <0.43 <1.0 <6.0 <1.0 <1.0 --

Loop 410 02/07/2013 SBQ 

(replicate)

E0.53 v <1.0 <6.0 <1.0 <1.0 --

Loop 410 04/29/2013 SS E9.6 v E1.0 n <6.0 <1.0 <1.0 --

Loop 410 05/14/2013 SB E0.46 v E0.43 n <6.0 <1.0 <1.0 --

Loop 410 05/14/2013 SBQ 

(replicate)

<0.63 E0.14 t <6.0 <1.0 <1.0 <4.0 m

Loop 410 05/24/2013 SS E4.0 v E0.16 t <6.0 <1.0 <1.0 <4.0 m

Loop 410 06/25/2013 SB <0.51 E0.07 t <6.0 <1.0 <1.0 E0.38 bmt

Loop 410 06/25/2014 SS E2.9 v 0.32 n <6.0 <1.0 0.04 bt E1.7 mt

Loop 410 07/22/2014 SB E0.43 v <1.0 <6.0 <1.0 <1.0 <4.0 m

Loop 410 07/22/2014 SBQ 

(replicate)

0.38 v <1.0 <6.0 <1.0 <1.0 <4.0 m

Rodriguez 

Park

11/15/2012 SB <0.48 <1.0 <6.0 <1.0 <1.0 --

Rodriguez 

Park

02/07/2013 SB <0.20 0.05 t <6.0 <1.0 <1.0 --

Rodriguez 

Park

04/29/2013 SS E2.6 v E0.34 n <6.0 <1.0 <1.0 --

Rodriguez 

Park

04/29/2013 SSQ 

(replicate)

E2.2 E0.42 n <6.0 <1.0 <1.0 --

Rodriguez 

Park

05/14/2013 SB <0.41 E0.14 t <6.0 <1.0 <1.0 <4.0 m

Rodriguez 

Park

05/24/2013 SS E2.6 v 0.27 t <6.0 <1.0 <1.0 <4.0 m

Rodriguez 

Park

06/24/2013 SB <0.90 <1.0 E0.36 bt <1.0 <1.0 E1.7 mt

Rodriguez 

Park

06/25/2014 SS E7.1 v 1.4 <6.0 <1.0 <1.0 E15.6 m
98 Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date

Medium 

code 

(QC sample 

type)

PBDE 

congener 99

(micrograms 

per 

kilogram)

Dechlorane 

plus

(micrograms 

per 

kilogram)

Methyl 

triclosan

(micrograms 

per 

kilogram)

Octachlorostyrene

(micrograms 

per 

kilogram)

Pentabromotoluene

(micrograms 

per 

kilogram)

Triclosan

(micrograms 

per 

kilogram)

Rodriguez 

Park

07/21/2014 SB E0.29 v <1.0 <6.0 <1.0 <1.0 <4.0 m

Morey Road 11/15/2012 SB <0.30 <1.0 <6.0 <1.0 <1.0 --

Morey Road 01/09/2013 SS Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Insufficient 

sediment

Morey Road 02/06/2013 SB <0.20 0.10 t <6.0 <1.0 <1.0 --

Morey Road 02/06/2013 SBQ 

(replicate)

E0.29 v E0.59 n <6.0 <1.0 <1.0 --

Morey Road 04/29/2013 SS E2.9 v E2.6 <6.0 <1.0 <1.0 E5.0 m

Morey Road 05/13/2013 SB <0.20 E0.14 t <6.0 <1.0 <1.0 <4.0 m

Morey Road 05/24/2013 SS E1.5 v E0.20 t <6.0 <1.0 <1.0 <4.0 m

Morey Road 05/24/2013 SSQ 

(replicate)

1.8 v <1.0 <6.0 <1.0 <1.0 <4.0 m

Morey Road 06/25/2013 SB <0.20 E0.31 n <6.0 <1.0 <1.0 <4.0 m

Morey Road 06/25/2013 SBQ 

(replicate)

<0.20 E0.29 t <6.0 <1.0 <1.0 <4.0 m

Morey Road 06/25/2014 SS E2.7 v 0.46 n <6.0 <1.0 <1.0 E14.3 m

Morey Road 07/21/2014 SB E0.16 v <1.0 <6.0 <1.0 <1.0 <4.0 m

Joint Base 11/16/2012 SB <0.66 0.71 n <6.0 <1.0 <1.0 --

Joint Base 11/16/2012 SBQ 

(replicate)

<0.47 <1.0 <6.0 <1.0 <1.0 --

Joint Base 02/06/2013 SB <0.76 0.42 n <6.0 <1.0 <1.0 --

Joint Base 05/13/2013 SB E1.2 v E0.75 n <6.0 <1.0 <1.0 --

Joint Base 06/24/2013 SB E1.2 v E0.96 n <6.0 <1.0 <1.0 <4.0 m

Joint Base 07/21/2014 SB E0.55 v 0.54 n <6.0 <1.0 <1.0 <4.0 m

-- 11/28/2012 SBQ (standard 

reference 

material)

E1.0 <1.0 <6.0 <1.0 <1.0 --

-- 04/09/2013 SBQ (standard 

reference 

material)

E0.73 E0.83 n <6.0 <1.0 <1.0 --
Table 8 99

Table 8. Concentrations of inorganic and organic constituents in streambed- and suspended-sediment samples collected from sites 

on Leon Creek, San Antonio, Texas, 2012–14.—Continued

[QC, quality control; NWQL, U.S. Geological Survey National Water Quality Laboratory; SB, bottom material; SBQ, QC sample - bottom material; SS, 

suspended sediment; SSQ, QC sample - suspended sediment; --, no data; <, less than; E, estimated; M, presence verified but not quantified; b, value extrapolated 

at low end; h, compound identified and verified after additional review; m, value is highly variable by this method; n, below the reporting level but at or above 

the detection level; t, below the detection level; v, analyte detected in laboratory blank]

Site 

identifier

(table 1)

Date Medium code 

(QC sample type)

Organic carbon, bed 

sediment, dry weight

(percent)

Thorium

(milligrams 

per kilogram)

Uranium

(milligrams 

per kilogram)

Loop 410 11/15/2012 SB 0.60 6.0 2.2

Loop 410 11/15/2012 SBQ (replicate) 0.23 6.0 2.3

Loop 410 01/09/2013 SS Insufficient sediment Insufficient sediment Insufficient sediment

Loop 410 02/07/2013 SB 0.86 5.0 2.0

Loop 410 02/07/2013 SBQ (replicate) 0.65 5.0 2.0

Loop 410 04/29/2013 SS 4.1 5.6 1.7

Loop 410 05/14/2013 SB 0.85 6.0 2.1

Loop 410 05/14/2013 SBQ (replicate) 0.85 5.0 2.0

Loop 410 05/24/2013 SS 1.7 5.9 2.0

Loop 410 06/25/2013 SB 0.59 7.0 2.1

Loop 410 06/25/2014 SS Insufficient sediment 7.2 1.9

Loop 410 07/22/2014 SB 0.77 5.0 2.2

Loop 410 07/22/2014 SBQ (replicate) 0.81 5.0 2.3

Rodriguez Park 11/15/2012 SB 1.5 8.0 2.1

Rodriguez Park 02/07/2013 SB 1.5 7.0 1.8

Rodriguez Park 04/29/2013 SS 3.0 7.4 1.7

Rodriguez Park 04/29/2013 SSQ (replicate) 3.1 7.3 1.7

Rodriguez Park 05/14/2013 SB 0.83 7.0 2.0

Rodriguez Park 05/24/2013 SS 1.9 7.2 1.9

Rodriguez Park 06/24/2013 SB 1.7 7.0 1.9

Rodriguez Park 06/25/2014 SS Insufficient sediment 7.9 2.0

Rodriguez Park 07/21/2014 SB 2.0 7.0 1.9

Morey Road 11/15/2012 SB 1.6 7.0 2.0

Morey Road 01/09/2013 SS Insufficient sediment Insufficient sediment Insufficient sediment

Morey Road 02/06/2013 SB 1.6 7.0 1.8

Morey Road 02/06/2013 SBQ (replicate) 1.6 6.0 1.9

Morey Road 04/29/2013 SS 4.6 Insufficient sediment Insufficient sediment

Morey Road 05/13/2013 SB 1.1 7.0 1.9

Morey Road 05/24/2013 SS 1.4 6.7 1.9

Morey Road 05/24/2013 SSQ (replicate) 1.7 6.9 1.9

Morey Road 06/25/2013 SB 1.4 7.0 1.7

Morey Road 06/25/2013 SBQ (replicate) 1.5 6.0 1.6

Morey Road 06/25/2014 SS Insufficient sediment 8.4 2.0

Morey Road 07/21/2014 SB 1.7 7.0 1.8

Joint Base 11/16/2012 SB 1.9 8.0 1.9

Joint Base 11/16/2012 SBQ (replicate) 1.6 8.0 1.9

Joint Base 02/06/2013 SB 1.8 6.0 1.6

Joint Base 05/13/2013 SB 1.1 7.0 1.7

Joint Base 06/24/2013 SB 1.4 8.0 1.9

Joint Base 07/21/2014 SB 2.0 7.0 1.6

-- 11/28/2012 SBQ (standard reference material) 2.6 9.0 3.0

-- 04/09/2013 SBQ (standard reference material) 2.3 8.0 2.7

1

Total PCB was computed as the sum of the 18 reported congeners using the Kaplan-Meier method for summing nondetects (Helsel, 2009).
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Information regarding water resources in Texas is available at 

http://tx.usgs.gov/
Wilson—Occurrence and Concentrations of Selected Trace Elements and Halogenated Organic Compounds in Stream Sediments—SIR 2016–5039

Printed on recycled paper

ISSN 2328-031X (print)

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20165039

I SBN 978- 1- 4113-4042- 8

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