Occurrence of Organic Wastewater Compounds

in Wastewater Effluent and the Big Sioux River

in the Upper Big Sioux River Basin, South Dakota,

2003–2004

Scientific Investigations Report 2005–5249

Prepared in cooperation with the East Dakota Water Development District

U.S. Department of the Interior

U.S. Geological Survey
Occurrence of Organic Wastewater

Compounds in Wastewater Effluent and

the Big Sioux River in the Upper Big Sioux 

River Basin, South Dakota, 2003–2004

By Steven K. Sando, Edward T. Furlong, James L. Gray, Michael T. Meyer, and 

Roy C. Bartholomay

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the East Dakota Water Development District

Scientific Investigations Report 2005-5249
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2005

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

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

reproduce any copyrighted materials contained within this report.

Suggested citation:

Sando, S.K., Furlong, E.T., Gray, J.L., Meyer, M.T., and Bartholomay, R.C., 2005, Occurrence of organic wastewater 

compounds in wastewater effluent and the Big Sioux River in the Upper Big Sioux River Basin, South Dakota, 2003–

2004: U.S. Geological Survey Scientific Investigations Report 2005-5249, 108 p.
 iii

Contents

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

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

Description of Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Methods of Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Sampling Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Collection, Processing, and Analysis of Water Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Calculation of Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Quality Assurance/Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Occurrence of Organic Wastewater Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Watertown Area Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Field-Measured Properties and Constituents and Auxiliary Constituents . . . . . . . . . . .14

Organic Wastewater Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Volga Area Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Field-Measured Properties and Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Organic Wastewater Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Brookings Area Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Field-Measured Properties and Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Organic Wastewater Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

Synopsis of Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Supplemental Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59

Figures

1. Map showing location of study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Map showing location of sampling sites and gaging stations in study area . . . . . . . . . . . 6

3-14. Graphs showing:

3. Flow conditions during sampling periods for sites in the Watertown area . . . . . . . 14

4. Results for selected field-measured properties and constituents and

auxiliary constituents in wastewater effluent and the Big Sioux River

in the Watertown area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5. Summary of results for organic wastewater compounds in wastewater

effluent and the Big Sioux River in the Watertown area. . . . . . . . . . . . . . . . . . . . . . . 19

6. Summary of results for endocrine-disrupting compounds (EDCs) from

all compound classes in wastewater effluent and the Big Sioux River

in the Watertown area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7. Flow conditions during sampling periods for sites in the Volga area . . . . . . . . . . . . 28

8. Results for selected field-measured properties and constituents and

auxiliary constituents in wastewater effluent and the Big Sioux River

in the Volga area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

9. Summary of results for organic wastewater compounds in wastewater

effluent and the Big Sioux River in the Volga area. . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
iv 

10. Summary of results for endocrine disrupting compounds (EDCs) from

all compound classes in wastewater effluent and the Big Sioux River

in the Volga area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

11. Flow conditions during sampling periods for sites in the Brookings area . . . . . . . . 39

12. Results for selected field-measured properties and constituents and

auxiliary constituents in wastewater effluent and the Big Sioux River

in the Brookings area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

13. Summary of results for organic wastewater compounds in wastewater

effluent and the Big Sioux River in the Brookings area. . . . . . . . . . . . . . . . . . . . . . . . 45

14. Summary of results for endocrine disrupting compounds (EDCs) from

all compound classes in wastewater effluent and the Big Sioux River

in the Brookings area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Tables

1. Selected characteristics of the Watertown, Volga, and Brookings wastewater 

treatment plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2. Sampling sites and streamflow-gaging stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. Intervening reach lengths between selected locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4. Statistical summaries of analytical results and load results for organic 

wastewater compounds in wastewater effluent and the Big Sioux River in 

the Watertown area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5. Detected organic wastewater compounds in wastewater effluent and the 

Big Sioux River in the Watertown area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6. Statistical summaries of analytical results and load results for organic 

wastewater compounds in wastewater effluent and the Big Sioux River

in the Volga area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7. Detected organic wastewater compounds in wastewater effluent and the 

Big Sioux River in the Volga area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8. Statistical summaries of analytical results and load results for organic 

wastewater compounds in wastewater effluent and the Big Sioux River 

in the Brookings area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

9. Detected organic wastewater compounds in wastewater effluent and the 

Big Sioux River in the Brookings area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

10. Field-measured properties and constituents and analytical constituents . . . . . . . . . . . . 61

11. Statistical summaries of analytical results for detected compounds in 

laboratory method-blank samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

12. Statistical summaries of analytical results for laboratory reagent-spike samples . . . . . 71

13. Statistical summaries of analytical results for laboratory surrogate samples. . . . . . . . . 74

14. Statistical summaries of analytical results for detected compounds in field 

equipment-blank samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

15. Statistical summaries for field replicate samples for organic wastewater 

compounds (OWCs) detected in any sample for any primary/replicate sample pair . . . 76

16. Statistical summaries for environmental matrix spikes for wastewater effluent 

and Big Sioux River samples collected in the Sioux Falls area during 2002–2004. . . . . . 79

17. Results for field-measured properties and constituents and auxiliary 

constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

18. Analytical results for human pharmaceutical compounds (HPCs). . . . . . . . . . . . . . . . . . . 85

19. Analytical results for human and veterinary antibiotic compounds (HVACs) . . . . . . . . . 89
 v

20. Analytical results for major agricultural herbicides (MAHs). . . . . . . . . . . . . . . . . . . . . . . . 94

21. Analytical results for household, industrial, and minor agricultural-use 

compounds (HIACs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

22. Analytical results for polyaromatic hydrocarbons (PAHs) . . . . . . . . . . . . . . . . . . . . . . . . 103

23. Analytical results for sterol compounds (SCs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Conversion Factors

Multiply By To obtain

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

foot (ft) 0.3048 meter (m)

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

mile (mi) 1.609 kilometer (km)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

pounds per day (lb/d) 0.4536 kilograms per day (Kg/d)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2)

yard (yd) 0.9144 meter (m)

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

°C = (°F - 32) / 1.8

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm).

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or 

micrograms per liter (μg/L).

Loads of organic wastewater compounds were estimated by multiplying discharges at the times 

of sampling by constituent concentrations and by a conversion factor (0.0053919) to convert 

cubic feet per second and micrograms per liter to pounds per day.
vi 

Definition of Acronyms

AHTN 7-Acetyl-1,1,3,4,4,6-hexamethyl tetrahydronaphthalene

AP Alkylphenols

DEET N,N-diethyl-meta-toluamide

EDCs Endocrine-disrupting compounds

HHCB 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl cyclopenta-g-2-benzopyran

HIACs Household, industrial, and minor agricultural use compounds

HLB Hydrophilic-lipophilic-balance

HPCs Human pharmaceutical compounds

HPLC/ESI-MS High-performance liquid chromatography/electrospray ionization mass 

spectrometry 

HVACs Human and veterinary antibiotic compounds

LRL Laboratory reporting level

MAHs Major agricultural herbicides

MCX Cation exchange cartridge

NP para-Nonylphenol

NP1EO Nonylphenol monoethoxylate

NP2EO Nonylphenol diethoxylate

NWQL U.S. Geological Survey National Water Quality Laboratory

OGRL U.S. Geological Survey Organic Geochemistry Research Laboratory

OP1EO Octylphenol monoethoxylate

OP2EO Octylphenol diethoxylate

OWCs Organic wastewater compounds

PAHs Polyaromatic hydrocarbons

QA/QC Quality assurance/quality control

RPD Relative percent difference

RSD Relative standard deviation

SCs Sterol compounds

SIM Selected ion monitoring

SPE Solid-phase extraction 

SRL Study reporting level

TMDL Total Maximum Daily Load

USGS U.S. Geological Survey

WWTP Wastewater treatment plant
Occurrence of Organic Wastewater Compounds in

Wastewater Effluent and the Big Sioux River in the

Upper Big Sioux River Basin, South Dakota, 2003–2004

By Steven K. Sando, Edward T. Furlong, James L. Gray, and Michael T. Meyer, and Roy C. Bartholomay

Abstract

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

the East Dakota Water Development District conducted a 

reconnaissance study to determine the occurrence of organic 

wastewater compounds (OWCs) in wastewater effluent and the 

Big Sioux River at or near the cities of Watertown, Volga, and 

Brookings in the upper Big Sioux River Basin during August 

2003 through June 2004. For each city, samples were collected 

from the wastewater treatment plant (WWTP) effluent and from 

Big Sioux River sites upstream and downstream from where the 

wastewater effluent discharges to the Big Sioux River. For 

Watertown and Brookings, samples were collected during a 

low-flow period (August 2003) and a runoff period (June 2004). 

For Volga, samples were collected during two low-flow periods 

(August 2003 and October 2003) and a runoff period (June 

2004).

A total of 125 different OWCs were analyzed for and were 

classified into six compound classes—human pharmaceutical 

compounds (HPCs), human and veterinary antibiotic compounds (HVACs), major agricultural herbicides (MAHs), 

household, industrial, and minor agricultural compounds 

(HIACs), polyaromatic hydrocarbons (PAHs), and sterol compounds (SCs). Of the 125 different OWCs, 45 had acceptable 

analytical method performance, were detected at concentrations 

greater than the study reporting levels, and were included in 

analyses and discussion related to occurrence of OWCs in 

wastewater effluents and the Big Sioux River.

OWCs in all six compound classes were detected in water 

samples from sampling sites in the Watertown area. The Watertown WWTP discharged continuously to the Big Sioux River 

during both the low-flow August 2003 and runoff June 2004 

sampling periods. Total OWC concentrations for Big Sioux 

River sites upstream from the Watertown WWTP discharge 

generally were small, less than 6 micrograms per liter (μg/L) for 

both sampling periods. SCs accounted for nearly all of the total 

OWC concentrations for upstream Big Sioux River sites for the 

low-flow August 2003 sampling period, and MAHs accounted 

for nearly all of the total OWC concentrations for the runoff 

June 2004 sampling period. Total OWC concentrations for 

samples collected from the Watertown wastewater effluent 

were relatively large for both sampling periods (estimated concentrations ranged from 20 to 41 μg/L), and primarily consisted 

of HIACs, SCs, and HVACs. Total OWC concentrations for 

Big Sioux River sites downstream from the Watertown WWTP 

discharge were relatively large for the low-flow August 2003 

sampling period (estimated concentrations ranged from 6.9 to 

19 μg/L) and smaller for the runoff June 2004 sampling period 

(estimated concentrations ranged from 3.3 to 6.5 μg/L), a pattern that probably reflects a greater fraction of the total flow of 

the Big Sioux River being derived from WWTP discharge 

during the low-flow sampling period. Major OWC classes contributing to total OWC concentrations for Big Sioux River sites 

downstream from the Watertown WWTP were HIACs, SCs, 

and HVACs. Total OWC concentrations decreased substantially between the two downstream Big Sioux River sites. 

Although confident conclusions could not be made primarily 

due to possible effects of non-Lagrangian sampling, OWC 

results for the Watertown area might indicate that (1) OWCs for 

upstream Big Sioux River sites probably were primarily contributed by nonpoint agricultural sources, with livestock agriculture accounting for most of the total OWC concentration for 

the low-flow August 2003 sampling period, and crop agriculture accounting for most of the total OWC concentration for the 

runoff June 2004 sampling period; (2) OWCs for downstream 

Big Sioux River sites were substantially influenced by contributions from the Watertown WWTP during both the low-flow 

and runoff sampling periods; and (3) contributions of OWCs 

that might be derived from nonpoint livestock agricultural 

sources increased in proportion for the most downstream site 

for both the low-flow and runoff sampling periods. Suspected 

endocrine-disrupting compounds (EDCs) were detected in all 

Big Sioux River samples in the Watertown area. For both the 

low-flow and runoff sampling periods, the numbers of EDCs 

detected, and EDC concentrations and loads generally were 

larger for downstream Big Sioux River sites than for upstream 

Big Sioux River sites. Combined EDC concentrations for 

downstream Big Sioux River sites consisted mostly of HIACs 

for the low-flow sampling period and both HIACs and MAHs 

for the runoff sampling period.
2 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

OWCs in all compound classes except PAHs were 

detected in samples from sites in the Volga area. The Volga 

WWTP was not discharging to the Big Sioux River during the 

low-flow August 2003 and runoff June 2004 sampling periods, 

but was discharging continuously to the Big Sioux River during 

the low-flow October 2003 sampling period. For the low-flow 

August 2003 sampling period, the upstream Big Sioux River 

site had larger total OWC concentrations and loads than downstream Big Sioux River sites, and SCs accounted for most of the 

total OWC concentration for all Big Sioux River sites. For the 

low-flow October 2003 sampling period, when the Volga 

WWTP was discharging to the Big Sioux River, total OWC 

concentrations and loads were larger for the downstream Big 

Sioux River site than for the upstream site, and the increase in 

load corresponded well with the load contributed by the Volga 

wastewater effluent discharge, especially for HIACs. HIACs 

and SCs accounted for most of the total OWC concentrations 

for Big Sioux River sites for the October 2003 sampling period. 

For the June 2004 runoff sampling period, the upstream Big 

Sioux River site had smaller total OWC concentrations and 

loads than downstream Big Sioux River sites, and MAHs 

accounted for most of the total OWC concentrations for all Big 

Sioux River sites. Although confident conclusions could not 

be made due to possible effects of non-Lagrangian sampling, 

the data might indicate that (1) for the low-flow August 2003 

sampling period, nonpoint livestock agricultural and/or human 

wastewater sources might have been the primary contributors to 

occurrence of OWCs at Big Sioux River sampling sites; (2) for 

the low-flow October 2003 sampling period, nonpoint livestock 

sources and upstream human wastewater sources primarily contributed to occurrence of OWCs at Big Sioux River sampling 

sites; (3) for the runoff June 2004 sampling period, nonpoint 

crop agricultural sources primarily contributed to occurrence of 

OWCs at Big Sioux River sampling sites; (4) for the low-flow 

August 2003 and runoff June 2004 sampling periods, seepage of 

water from the Volga WWTP had little effect on downstream 

OWC concentrations; and (5) for the low-flow October 2003 

sampling period, the Volga wastewater effluent discharge contributed to downstream OWC concentrations. EDCs were 

detected in all samples collected from sampling sites in the 

Volga area. For all sampling periods, total EDC concentrations 

generally were similar between upstream and downstream Big 

Sioux River sites and consisted of HIACs and MAHs. HIACs 

accounted for most of the total EDC concentrations for the lowflow August 2003 and October 2003 sampling periods, and 

MAHs accounted for most of the total EDC concentrations for 

the runoff June 2004 sampling period for all Big Sioux River 

sites.

OWCs in all compound classes except PAHs were 

detected in water samples from sampling sites in the Brookings 

area. The Brookings WWTP discharged continuously to the Big 

Sioux River during all sampling periods. For the low-flow 

August 2003 sampling period, the upstream site had slightly 

smaller total OWC concentrations and loads compared to the 

downstream Big Sioux River sites. SCs and HIACs accounted 

for most of the total OWC concentration in all Big Sioux River 

sampling sites, but the proportion of SCs increased at the most 

downstream site. For the runoff June 2004 sampling period, the 

upstream site generally had smaller total OWC concentrations 

and loads than downstream Big Sioux River sites. MAHs 

accounted for most of the total OWC concentration for all Big 

Sioux River sites, but the proportion of SCs increased at the 

most downstream site. Although confident conclusions could 

not be made due to possible effects of non-Lagrangian sampling, the data might indicate that (1) for the low-flow August 

2003 sampling period, nonpoint livestock agricultural sources 

probably primarily contributed to occurrence of OWCs at all 

Big Sioux River sampling sites, and the Brookings WWTP 

wastewater effluent discharge contributed but did not have a 

substantial effect on concentrations at downstream sites; and 

(2) for the runoff June 2004 sampling period, nonpoint crop 

agricultural sources primarily contributed to occurrence of 

OWCs at all Big Sioux River sites, contributions of OWCs that 

might be derived from nonpoint livestock agricultural sources 

increased in proportion to other sources for the most downstream site, and the Brookings WWTP wastewater effluent 

discharge probably did not substantially contribute to total 

OWC concentrations at downstream sampling sites. EDCs were 

detected in all samples collected from sampling sites in the 

Brookings area. Total EDC concentrations for the upstream site 

consisted entirely of MAHs. Total EDC concentrations for 

downstream sites consisted of MAHs and HIACs. HIACs 

accounted for most of the total EDC concentrations for the lowflow August 2003 sampling period, and MAHs accounted for 

most of the total EDC concentrations for the runoff June 2004 

sampling period for downstream Big Sioux River sites.

The city of Watertown is located near the upstream part of 

the Big Sioux River Basin, where the mean annual flow of the 

Big Sioux River is less than 100 cubic feet per second (ft3

/s). 

Watertown WWTP discharges can account for a substantial part 

of the flow in the Big Sioux River, especially during low-flow 

periods. Effects of the Watertown WWTP wastewater effluent 

discharges on the occurrence of OWCs in the Big Sioux River 

downstream were apparent during both the low-flow and runoff 

sampling periods. For Volga and Brookings, which are farther 

downstream and where the mean annual flow of the Big Sioux 

River exceeds 400 ft3/s, wastewater effluent discharges from 

the Volga and Brookings WWTPs probably influenced the 

occurrence of OWCs in the Big Sioux River, but probably did 

not substantially contribute to total OWC concentrations, 

especially during the runoff sampling period.

Introduction

Many organic compounds used in or produced by household, industrial, and agricultural activities are soluble and resistant to wastewater treatment processes, and have been shown to 

occur in wastewater discharges to natural streams (Richardson 

and Bowron, 1985; Halling-Sorensen and others, 1998). Additionally, some of these organic wastewater compounds (OWCs) 
Description of Study Area 3

can persist in natural water systems and potentially have longterm effects on stream biota; human exposure also might occur 

when those systems are used as water supplies (Barnes and 

others, 2002; Kolpin and others, 2002; Stackelberg and others, 

2004). Some OWCs are hormonally active and have been 

shown to disrupt the endocrine systems of animals in laboratory 

studies (Jobling and others, 1996; Thorpe and others, 2001). 

Evidence also indicates that endocrine systems of some fish and 

other vertebrate animals in natural systems have been affected 

by OWCs (Sumpter and Johnson, 2005), although after a 

decade of intensive research in the laboratory and field, the 

mechanisms of endocrine modulation and the long-term, sublethal effects of low-level exposure to OWCs remain poorly 

understood. Thus, data documenting the concentrations and 

composition of OWC mixtures in the environment contribute to 

the understanding of the potential effect these chemicals might 

have in the environment.

Within the Big Sioux River drainage basin in eastern South 

Dakota (fig. 1), considerable agricultural activities occur; both 

crops and livestock are raised, and numerous concentrated 

animal feeding operations exist. Potential exists for OWCs 

associated with agricultural activities, including pesticides, 

antibiotics, and feed supplements from feeding operations, to be 

introduced into both surface and ground water in the basin. 

Additionally, wastewater discharges from some of the larger 

cities in South Dakota (including Watertown, Brookings, and 

Sioux Falls) along with discharges from several smaller cities 

are released directly into the Big Sioux River. These wastewater 

discharges also might contain OWCs.

The upper Big Sioux River Basin has been a focus for 

Total Maximum Daily Load (TMDL) activities, and a largescale assessment currently is underway. Reaches of the upper 

Big Sioux River are listed in the South Dakota 303(d) Water 

List (South Dakota Department of Environment and Natural 

Resources, 2004) as being impaired for dissolved oxygen, fecal 

coliform, nitrate, and total suspended solids. Most of these 

impairments are directly influenced by contributions of either 

human and/or animal wastes. Although OWCs are not directly 

related to TMDL impairments in the upper Big Sioux River 

Basin, it is possible that information on the occurrence of 

emerging contaminants will provide useful information in 

tracking sources of TMDL contaminants. Also, information on 

the occurrence of OWCs in the upper Big Sioux River Basin can 

provide valuable information of the ecosystem health of the 

upper Big Sioux River.

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

the East Dakota Water Development District, conducted a 

reconnaissance study to determine the occurrence of OWCs in 

wastewater effluent and the Big Sioux River in the upper Big 

Sioux River Basin during August 2003 through June 2004. 

Samples were collected during summer/fall low-flow conditions in 2003 and after a rainfall event in the early summer of 

2004 to evaluate flow conditions on the occurrence of OWCs.

The purpose of this report is to describe the occurrence of 

OWCs in wastewater effluent and the Big Sioux River near the 

cities of Watertown, Volga, and Brookings during 2003–2004. 

Specifically, this report describes the data-collection and analytical methods used in the study, and the analytical results 

documenting the presence, concentrations, and distributions of 

these environmentally significant OWCs in the upper Big Sioux 

River Basin.

The OWCs analyzed for in this study (table 10 in the 

Supplemental Information section at the end of the report) are 

classified into the following six compound classes: (1) human 

pharmaceutical compounds (HPCs), which are commonly used 

prescription and non-prescription pharmaceutical drugs; 

(2) human and veterinary antibiotic compounds (HVACs), 

which are prescription drugs used in the treatment of infectious 

diseases; (3) major agricultural herbicides (MAHs), which 

include atrazine, metolachlor, and prometon; (4) household, 

industrial, and minor agricultural compounds (HIACs), which 

are various generally synthetic organic compounds used for a 

variety of purposes, including detergents, fire retardants, plasticizers, fragrances, solvents, preservatives, and disinfectants; 

(5) polyaromatic hydrocarbons (PAHs), which are compounds 

often occurring in fossil fuels or produced by the combustion of 

fossil fuels; and (6) sterol compounds (SCs), which are predominantly unsaturated solid alcohols of the steroid group naturally 

occurring in fatty tissues of plants and animals and present in 

animal fecal material. Some of the compounds in the HPC, 

MAH, HIAC, and PAH classes are suspected of being 

endocrine-disrupting compounds (EDCs).

Description of Study Area

The Big Sioux River Basin originates in northeastern 

South Dakota and extends southerly along the eastern edge of 

the State (fig. 1). The Big Sioux River drains an extended highland or plateau, the Coteau des Prairie, which is the largest 

single topographic feature in eastern South Dakota (Lawrence 

and Sando, 1989). The coteau is a 200-mi-long constructional 

remnant from glacial ice sheets that moved south along the 

eastern edge of South Dakota (Flint, 1971; Leap, 1988). The 

study area comprises about 3,900 mi2 in the upper part of the 

basin, from the headwaters of the Big Sioux River downstream 

to an area south of Brookings (fig. 1).

The climate in the study area is continental and is characterized by large seasonal and daily variations in temperature. 

The normal (1971–2000) mean daily July temperature is about 

70.5°F, and the normal mean daily January temperature is about 

-10.6°F (South Dakota State University, 2005a). Normal annual 

precipitation (1971–2000) is about 22.5 in. (South Dakota State 

University, 2005b). On average, about 80 percent of annual precipitation occurs as rainfall during the months of April through 

October.

Land use in the study area is primarily agricultural with 

corn, wheat, soybeans, miscellaneous small grains, and alfalfa 

as the major crops (Lawrence and Sando, 1989). Livestock 

raised in the basin primarily include dairy cattle, beef cattle, and 

hogs. The cities of Watertown and Brookings are the major 
SOUTH DAKOTA

SOUTH DAKOTA

MINNESOTA

NEBRASKA

SOUTH DAKOTA

MISSOURI

RIVER

Area

shown

Big

Sioux

River ") ") ") ") ") ") ")

Volga

Bruce

Watertown Watertown

Estelline Estelline

Brookings Brookings

Castlewood Castlewood

Volga

Bruce

Watertown

Estelline

Brookings

Flandreau )

Castlewood

Sioux

Falls

#

06485500 06485500 6485500

98° 97°

43°

44°

45°

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS Base from U.S. Geological Survey digital data, 1:100,000, 1985

Universal Traverse Mercator projction, zone 14

EXPLANATION

# Gaging station—Number is station

 identification number

Study area

Big Sioux River drainage basin boundary

4 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 1. Location of study area.
Methods of Study 5

urban areas in the study area. Smaller cities in the study area 

that are close to the Big Sioux River channel include Castlewood, Estelline, Bruce, and Volga (fig. 1). Occurrence of 

OWCs in wastewater effluent and the Big Sioux River near the 

cities of Watertown, Volga, and Brookings were investigated in 

this study.

The Big Sioux River is a major tributary to the Missouri 

River in eastern South Dakota and is a major water source for 

many cities in eastern South Dakota, including Sioux Falls, the 

largest city in South Dakota. The mean annual flow of the Big 

Sioux River for water years 1977–2004 is about 99 ft3

/s for 

USGS gaging station 06479525 (located about 15 river miles 

downstream from the city of Watertown (fig. 2); contributing 

drainage area is about 780 mi2), about 434 ft3

/s for USGS 

gaging station 06480000 (located about 20 river miles downstream from the city of Brookings (fig. 2); contributing drainage area is about 2,815 mi2

), and about 1,940 ft3/s for USGS 

gaging station 06485500 (located about 55 river miles upstream 

from the confluence with the Missouri River near Sioux City, 

Iowa (fig. 1); contributing drainage area is about 7,345 mi2) 

(data from U.S. Geological Survey, 2005; drainage areas 

revised from previously reported values; Ryan F. Thompson, 

U.S. Geological Survey, written commun., 2005).

Outwash deposits along the Big Sioux River and its tributaries underlie much of the upper Big Sioux River Basin 

(Lawrence and Sando, 1989). These outwash deposits include 

the various units of the Big Sioux aquifer, which is one of the 

more extensively developed aquifers in South Dakota. The outwash deposits range in thickness from a few feet to 200 ft and 

consist of cross-bedded gravel, sand, and silt, and range in depth 

below land surface from about 1 to 100 ft (Lawrence and Sando, 

1989). Many of the outwash deposits have areas where they are 

hydraulically connected with the Big Sioux River.

Watertown and Brookings are the two largest cities in the 

upper Big Sioux River Basin, with populations in 2000 of 

20,237 and 18,504, respectively (U.S. Census Bureau, 2005). 

Volga is a smaller farming community with a population of 

1,435. Characteristics of the wastewater treatment plants 

(WWTPs) for Watertown, Volga, and Brookings are presented 

in table 1. The WWTPs at Watertown and Brookings discharge 

continuously to the Big Sioux River. During low-flow periods, 

the wastewater discharges for Watertown can account for more 

than 75 percent of the Big Sioux River streamflow for several 

miles downstream, and the wastewater discharges for Brookings can account for more than 25 percent of the Big Sioux 

River streamflow for several miles downstream. Wastewater 

effluent leaves the Watertown WWTP in a concrete pipe about 

0.5 mi in length that discharges to a natural channel about 50 yd 

upstream from the confluence of the channel with the Big Sioux 

River. Wastewater effluent leaves the Brookings WWTP in a 

concrete pipe about 1.4 mi in length that discharges to a natural 

channel about 100 yd upstream from the confluence of the 

channel with the Big Sioux River. The Volga WWTP discharges intermittently to the Big Sioux River. Part of the treatment process of the Volga WWTP involves holding the wastewater in lagoons and a large wetland area for substantial periods 

of time during which the wastewater undergoes natural biological processing. When discharges from the Volga WWTP 

occur, the wastewater effluent is discharged directly into an 

intermittent surface-water channel and then travels about 

0.25 mi to the confluence with the Big Sioux River. Prior to the 

first sampling period for this study (August 2003), the Volga 

WWTP had last discharged to the Big Sioux River during 

April 1–30, 2003. The Volga WWTP also discharged continuously during October 1–31, 2003. The lagoons and the wetland 

area are located immediately adjacent to the Big Sioux River 

channel. The smallest distance between the lagoons and the Big 

Sioux River channel is about 300 ft, and the smallest distance 

between the wetland area and the Big Sioux River channel is 

about 620 ft. Monitoring wells located between the 

lagoons/wetland area and the Big Sioux River channel have 

indicated substantial seepage of water from the lagoons and 

wetland area into shallow ground water (Steven Meyer, Volga 

WWTP operator, oral commun., 2005). Any contaminated 

shallow ground water might discharge to the Big Sioux River at 

times.

Methods of Study

Water samples were collected at 12 sites to investigate the 

occurrence of OWCs in wastewater effluent and the Big Sioux 

River (fig. 2; table 2) at or near the cities of Watertown, Volga, 

and Brookings. For each city, samples were collected from the 

WWTP effluent, and from the Big Sioux River at sites upstream 

and downstream from where the wastewater effluent enters the 

Big Sioux River. 

Sampling Sites

A labeling scheme is used for the sampling sites consisting 

of a 2-character identifier of the city, and a 3-character identifier 

of the relation between the sampling site and the wastewater 

effluent. Values of the 2-character identifier of the city are 

defined as follows:

WT = Watertown;

VL = Volga; and

BK = Brookings.

Values of the 3-character identifier of the relation between 

the sampling site and the wastewater effluent are defined as 

follows:

US1 = Big Sioux River site farthest upstream from the 

wastewater discharge point (that is, where the wastewater 

effluent enters the Big Sioux River) of the given city;

US2 = Big Sioux River site closest upstream from the 

wastewater discharge point;

WWE = wastewater effluent site of the given city;

DS1 = Big Sioux River site closest downstream from the 

wastewater discharge point of the given city; and

DS2 = Big Sioux River site farthest downstream from the 

wastewater discharge point of the given city.
DAY

CLARK

GRANT

DEUEL

MINER

KINGSBURY

HAMLIN

MOODY

BROOKINGS

CODINGTON

ROBERTS

BEADLE

MARSHALL

SANBORN SPINK BROWN

LAKE

CODINGTON

HAMLIN

BROOKINGS

LAKE MOODY

Big

Sioux

River

Big

Pelican Lake

Willow

Creek

Sioux

River

Big

Sioux

River

Lake

Kampeska

Clear

Lake

Sixmile

Medary

Deer

North

Deer

Creek

Creek

Creek

Creek

Lake

Campbell

Lake

Goldsmith

29

29

29

14

14

81

81

212

212

29

29

81

81

212 212

14

14

29

29

") ") ") ")") ")

Volga

Bruce

Watertown Watertown

Estelline Estelline

Brookings Brookings

Castlewood Castlewood

Volga

Bruce

Watertown

Estelline

Brookings

Castlewood

") ")

Watertown

Castlewood

") ") ")

Volga

Bruce

Brookings

E

E

E

E

WT-DS2 E

WT-DS1

WT-WWE

WT-US2

WT-US1

E

E

E

E

E

E

E BK-DS2

WT-DS1

BK-DS1

BK-WWE

VL-DS1

VL-WWE

VL-US1

VL-DS2/BK-US1

E

#

#

#

#

#

#

06479525

06479500

06479500

06479512

06479520

06480000

06479770

Base from U.S. Geological Survey digital data, 1:100,000, 1985

Universal Traverse Mercator projction, zone 14

EXPLANATION

# Gaging station—Number is station

 identification number

Sampling site and site label

Study area

Big Sioux River study area boundary

98°00' 97°30' 97°00' 96°30'

44°00’

44°30'

45°00’

45°30'

97°10' 97°5' 97°00'

44°45'

44°50'

44°55'

96°55' 96°50' 96°45

44°10'

44°15'

44°20'

44°25'

0 5 1 2 3 4 Miles

0 23 1 45 Kilometers

0 5 1 2 3 4 MILES

0 2 1 3 4 5 KILOMETERS

0 25 MILES

0 25 KILOMETERS

6 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 2. Location of sampling sites and gaging stations in study area.
Table 1. Selected characteristics of the Watertown, Volga, and Brookings wastewater treatment plants.

[--, no data]

Watertown wastewater

treatment plant

Volga wastewater

treatment plant

Brookings wastewater

treatment plant

Population 20,237 1,435 18,504

Population density (people per 

square mile)

1,331.4 1,863.6 1,549.7

Design capacity (million gallons 

per day)

4 -- 3

Number of permitted industries 12 2 5

General description of permitted 

industries

Primarily metal finishers, one 

rubber manufacturer

Dairy-products manufacturer, 

soybean processor

Primarily metal finishers, one nonpharmaceutical medicinal 

products manufacturer, one 

electronics manufacturer

Preliminary treatment Screening and grit removal Screening and grit removal Screening and grit removal

Primary treatment Settling basin clarification Cell aeration Settling basin clarification

Secondary treatment Trickling filtration; aerated 

activated-sludge processing; 

secondary clarification

Lagoon holding and natural 

processing

Rotating-biological-contacter 

processing; aerated activatedsludge processing; secondary 

clarification; sand gravity 

filtration

Tertiary treatment Ultraviolet light disinfection; 

post-treatment aeration

Wetland holding and natural 

processing

Chlorine disinfection; posttreatment aeration; addition of 

sulfur dioxide to neutralize 

chlorine

Primary sludge treatment Anaerobic digestion Anaerobic digestion Anaerobic digestion

Methods of Study 7

For the Watertown area, there were two sampling sites on 

the Big Sioux River upstream from the wastewater discharge 

point—the Big Sioux River site farthest upstream from the 

wastewater discharge point is designated WT-US1, and the Big 

Sioux River site closest upstream from the wastewater discharge point is designated WT-US2. The Big Sioux River site 

farthest downstream from the Volga wastewater discharge point 

was co-located with the site upstream from the Brookings 

wastewater discharge point. This site is designated VL-DS2/

BK-US1. Information on intervening reach lengths for the 

sampling sites is presented in table 3.

Collection, Processing, and Analysis of Water

Samples

Samples were collected at sites in or near Watertown, 

Volga, and Brookings during August 18–22, 2003, and 

June 15–18, 2004. During these periods, the Watertown and 

Brookings WWTPs were continuously discharging to the Big 

Sioux River, but the Volga WWTP was not discharging. The 

Volga WWTP continuously discharged to the Big Sioux River 

during October 1–31, 2003. During this period, the maximum 

wastewater effluent discharge was about 0.7 ft3

/s, and the 

average discharge was about 0.6 ft3

/s (Steven Meyer, Volga 

WWTP operator, oral commun., 2005). To assess effects of the 

Volga WWTP discharges on the Big Sioux River, samples were 

collected at sites VL-US1, VL-WWE, and VL-DS1 during 

October 21–22, 2003. The wastewater effluent discharge at the 

time of sampling was estimated to be 0.6 ft3/s.

Samples generally were collected in upstream-to-downstream order, especially for the Big Sioux River sampling sites. 

Available resources did not allow conducting a Lagrangian 

scheme that samples a given pulse of water as it moves downstream. However, the timing of sample collection probably provided a reasonable representation of consistent flow conditions 

at sites upstream and downstream from the WWTP effluent discharges during the sampling periods to assess the effects of the 

discharges on water quality.
Table 2. Sampling sites and streamflow-gaging stations.

[mi2, square miles; e, estimated; --, not applicable]

Sampling site 

number

Station

identification

number

Station name

Site label

(figs. 1 and 2)

Drainage 

area1

(mi2)

Contributing 

drainage 

area1

(mi2)

Latitude Longitude

Sampling sites at or near Watertown, South Dakota

1 06479500 Big Sioux River at Watertown, 

SD

WT-US1 e1,010 e230 445633 0970845

2 06479512 Big Sioux River at Broadway, at 

Watertown, SD

WT-US2 e1,280 e595 445322 0970707

3 445301097055900 Watertown wastewater effluent at 

Watertown, SD

WT-WWE -- -- 445301 0970559

4 445234097054800 Big Sioux River below 

wastewater effluent at 

Watertown, SD

WT-DS1 e1,285 e600 445234 0970548

5 06479520 Big Sioux River below 

Watertown, SD

WT-DS2 e1,400 e760 445032 0970257

-- 06479525 Big Sioux River near 

Castlewood, SD

-- e1,500 e780 444354 0970239

Sampling sites at or near Volga, South Dakota

-- 06479770 Big Sioux River near Bruce, SD -- e2,800 e1,740 442804 0965314

6 442023096533600 Big Sioux River near Volga, SD VL-US1 e2,915 e1,860 442023 0965336

7 441913096533400 Volga wastewater wetland near 

Volga, SD

VL-WWE -- -- 441913 0965334

8 441841096521400 Big Sioux River below 

wastewater wetland, near 

Volga, SD

VL-DS1 e3,020 e1,940 441841 0965214

9 441422096491200 Big Sioux River above 

wastewater effluent, near 

Brookings, SD

VL-DS2/

BK-US1

e3,235 e2,155 441421 0964912

Sampling sites at or near Brookings, South Dakota

9 441422096491200 Big Sioux River above 

wastewater effluent, near 

Brookings, SD

VL-DS2/

BK-US1

e3,235 e2,155 441421 0964912

10 441434096482500 Brookings wastewater effluent 

near Brookings, SD

BK-WWE -- -- 441434 0964825

11 441316096483300 Big Sioux River below 

wastewater effluent, near 

Brookings, SD

BK-DS1 e3,495 e2,415 441316 0964833

12 441151096472200 Big Sioux River above Medary 

Creek, at Medary, SD

BK-DS2 e3,525 e2,445 441151 0964722

-- 06480000 Big Sioux River near Brookings, 

SD

-- e3,900 e2,815 441048 0964455

-- 06481000 Big Sioux River near Dell 

Rapids, SD

-- e4,480 e3,400 434725 0964442

-- 06485500 Big Sioux River at Akron, IA -- e8,425 e7,345 425014 0963341

1

Drainage areas revised from previously reported values (Ryan F. Thompson, U.S. Geological Survey, written commun., 2005).

8 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 3. Intervening reach lengths between selected locations.

[e, estimated; --, not applicable]

Starting location Ending location

Intervening 

reach length, in

river miles

For Big Sioux River sampling sites, 

distance from starting location to 

confluence of wastewater

effluent channel with

Big Sioux River for specified city

Study site WT-US1 (USGS gaging 

station 06479500)

Study site WT-US2 (USGS gaging 

station 06479512)

5.2 6.8 river miles upstream from 

WT-WWE confluence

Study site WT-US2 (USGS gaging 

station 06479512)

Confluence of Watertown wastewater 

effluent channel and Big Sioux 

River

1.5 1.5 river miles upstream from 

WT-WWE confluence

Study site WT-WWE Confluence of Watertown wastewater 

effluent channel and Big Sioux 

River

e.5 --

Confluence of Watertown wastewater 

effluent channel and Big Sioux River

Study site WT-DS1 .10 --

Study site WT-DS1 Study site WT-DS2 (USGS gaging 

station 06479520)

4.7 0.10 river miles downstream from 

WT-WWE confluence

Study site WT-DS2 (USGS gaging 

station 06479520)

USGS gaging station 06479525 14 4.8 river miles downstream from 

WT-WWE confluence

USGS gaging station 06479525 USGS gaging station 06479770 e36 --

USGS gaging station 06479770 Study site VL-US1 e15 --

Study site VL-US1 Study site VL-DS1 5.2 3.4 river miles upstream from 

VL-WWE confluence

Study site VL-WWE Confluence of Volga wastewater 

effluent channel and Big Sioux 

River

.24 --

Confluence of Volga wastewater 

effluent channel and Big Sioux 

River

Study site VL-DS1 1.9 --

Study site VL-DS1 Study site VL-DS2/BK-US1 7.4 1.8 river miles downstream from 

VL-WWE confluence

Study site VL-DS2/BK-US1 Study site BK-DS1 5.1 9.3 river miles downstream from 

VL-WWE confluence; 4.85 river 

miles upstream from BK-WWE 

confluence

Study site BK-WWE Confluence of Brookings wastewater 

effluent channel and Big Sioux 

River

e1.4 --

Confluence of Brookings wastewater 

effluent channel and Big Sioux 

River

Study site BK-DS1 .22 --

Study site BK-DS1 Study site BK-DS2 4.2 0.22 river miles downstream from 

BK-WWE confluence

Study site BK-DS2 USGS gaging station 06480000 4.7 4.4 river miles downstream from 

BK-WWE confluence

USGS gaging station 06480000 USGS gaging station 06485500 e200 --

Methods of Study 9
10 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

At each Big Sioux River sampling site, streamflow was 

determined using standard USGS procedures (Rantz and others, 

1982a, 1982b). WWTP wastewater effluent discharges at the 

time of sampling were determined from monitoring records 

provided by the WWTPs (Craig Mitchell, Watertown WWTP 

operator, written commun., 2005; Gary Englund, Brookings 

WWTP operator, written commun., 2005; Steven Meyer, Volga 

WWTP operator, oral commun., 2005). Other field-measured 

properties and constituents (table 10) were determined using 

standard USGS procedures (U.S. Geological Survey, 1997–

2004). Depth-integrated grab samples were collected near the 

centroid of flow for analysis of auxiliary constituents, including 

nitrite plus nitrate nitrogen, total coliform bacteria, and fecal 

coliform bacteria (table 10) using standard USGS procedures 

(U.S. Geological Survey, 1997–2004).

Water-quality samples for analysis of OWCs were collected and processed using standard USGS techniques (U.S. 

Geological Survey, 1997–2004) (table 10). Containers and 

sampling equipment contacting the sample water were constructed of fluorocarbon polymer, glass, aluminum, or stainless 

steel and were rigorously cleaned using standard USGS procedures. Ultra-clean two-person sampling procedures were used 

(“Clean hands/Dirty hands”), and sampling teams wore powderless nitrile gloves. Special requirements, including avoiding 

use of insect repellents, sunscreen, tobacco, caffeine, and pharmaceutical drugs by the sampling team, also were adhered to for 

collection of wastewater, pharmaceutical, and antibiotic compounds (U.S. Geological Survey, 1997–2004). 

Wastewater effluent samples were collected using a depthintegrated grab from the centroid of the effluent channel downstream from all treatment activities. Water samples from the Big 

Sioux River were collected using standard USGS width- and 

depth-integrating procedures, generally at 5 to 10 verticals 

across the sampling transect. Following collection, samples 

were composited into a glass or fluorocarbon polymer compositing container that was immediately chilled and transported to 

a laboratory processing area. Samples were processed at the laboratory processing area within a few hours of sample collection. 

The composite samples were split, filtered (if required), 

decanted into final sample bottles, packaged with ice, and sent 

by one-day shipping to the analytical laboratories. Where 

appropriate, filtration was performed by passing sample water 

through a pre-conditioned 0.7-millimeter (mm) nominal-pore 

size baked glass-fiber filter. In this report, constituents in filtered water samples are referred to as “dissolved,” which is 

operationally defined as that part of a water sample that passes 

through a 0.7-mm nominal-pore size baked glass-fiber filter. 

Constituents in unfiltered water samples are referred to as 

“whole-water.”

Analyses for nitrite-plus-nitrate nitrogen were performed 

at the USGS National Water Quality Laboratory (NWQL) in 

Denver, Colorado, by colorimetry (Fishman, 1993). Analyses 

for total and fecal coliform bacteria were performed at the South 

Dakota State Public Health Laboratory by most-probablenumber method and membrane filter method, respectively 

(American Public Health Association, 1998).

Concentrations of a total of 125 different OWCs were 

determined by laboratories using three different analytical 

methods, and the analytical results were analyzed to describe 

the occurrence of OWCs in wastewater effluent and the Big 

Sioux River (table 10). Analyses for OWCs were performed at 

USGS laboratories that are developing and/or refining smallconcentration (less than 1 microgram per liter (μg/L)) analytical 

methods. The following three analytical methods were used:

Analytical method 1 (performed at NWQL) determined 

concentrations of 20 prescription and nonprescription HPCs 

and selected metabolites and 4 HVACs in filtered water 

samples (table 10; Cahill and others, 2004) by using hydrophilic-lipophilic-balance (HLB) solid-phase extraction (SPE) 

cartridges. Pharmaceuticals concentrated in sample extracts 

were separated, identified, and quantified by reversed-phase, 

high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) using selected ion 

monitoring (SIM) and operated in the positive ionization mode.

Analytical method 2 (performed at the USGS Organic 

Geochemistry Research Laboratory (OGRL) in Lawrence, 

Kansas, analyzed for 38 HVACs in filtered water samples 

(table 10). Target compounds were extracted from water samples using tandem SPE that included an Oasis HLB cartridge 

followed by a mixed mode HLB cation exchange cartridge 

(MCX) (Meyer and others, 2000; Lee and others, 2004). 

Extracts were separated and measured by HPLC/ESI-MS using 

SIM. Prior to December 2003, samples were analyzed at OGRL 

using a single quadrapole HPLC mass spectrometer. After 

December 2003, samples were analyzed at OGRL using a triple 

quadrapole HPLC mass spectrometer that reduced the laboratory reporting levels (LRLs) by a factor of about 10. 

Analytical method 3 (performed at NWQL) determined 2 

nonprescription HPCs, 3 MAHs, 48 HIACs, 11 PAHs, and 4 

SCs in whole-water samples (table 10). Target compounds were 

extracted from water samples using continuous liquid-liquid 

extraction with methylene chloride at pH 2.0 (Lee and others, 

2004). Extracts were separated and measured by gas chromatography/mass spectrometry using electron impact ionization 

and operated in the full-scan mode.

The determination of compounds of interest was a twostep process. First the compound was qualitatively identified 

followed by a quantitative determination of concentration. 

Strict criteria were used to assess both steps prior to reporting a 

compound and its concentration (Barnes and others, 2002; 

Kolpin and others, 2002; Lee and others, 2004). The first step 

of qualitative identification was the presence of the compound 

of interest within an expected chromatographic retention time. 

If present within the chromatographic window, compound mass 

spectrum and diagnostic ion abundance ratios were required to 

match that of the reference compound standard. After qualitative identification criteria were attained, analyte concentrations 

were calculated using a 5- to 8-point calibration curve (concentrations generally from 0.01 to 10.0 μg/L) using internal standard quantitation. The most abundant ion typically was used 

for quantitation, and, if possible, as many as two diagnostic 
Methods of Study 11

fragment qualifier ions were used for ion abundance ratio confirmation. For analytical method 2, calibration standards were 

processed throughout the extraction procedure, which generally 

corrects concentrations for methodological losses during 

extraction, but not for matrix effects. Analytical methods 1 and 

3 do not extract calibration standards; thus, the reported compound concentrations determined using these methods were not 

corrected for method losses.

LRLs were determined for each analyte by a previously 

published procedure (U.S. Environmental Protection Agency, 

1992, for analytical methods 1 and 3). Selected analyte concentrations were flagged with an “e” to indicate estimated values. 

Several of the reasons that the concentration of a qualitatively 

identified compound was qualified as an estimate include concentrations that fell outside the calibration range, concentrations for analytes with average recoveries less than 60 percent, 

analytes routinely detected in laboratory blanks, and constituents with reference standards prepared from technical mixtures 

(Barnes and others, 2002; Kolpin and others, 2002; Lee and 

others, 2004). Quality assurance/quality control (QA/QC) data 

were analyzed in detail, and for compounds that were determined to have acceptable QA/QC results, estimated values 

flagged with an “e” were considered to be reasonable estimates 

of actual concentrations and were included in analyses and 

discussions related to occurrence of OWCs.

In addition to the OWCs discussed above, samples also 

were analyzed for bromoform and four human hormone compounds (17-beta-estradiol, equilenin, estrone, and ethynyl estradiol). Bromoform is a volatile organic compound that typically 

occurs as a disinfection by-product and requires special sampling procedures (that were not used in this study) for accurate 

quantitation. Thus, analytical results for bromoform are not 

included in this report. NWQL has determined that the performance of the analytical methods for the four human hormone 

compounds have not yet been adequately verified to report the 

analytical results, given the particularly sensitive nature of the 

occurrence of these compounds in aquatic systems. Thus, 

analytical results for the four human hormone compounds are 

not included in this report.

Five OWCs, including two HPCs (caffeine and cotinine) 

and three HVACs (erythromycin, sulfamethoxazole, and trimethoprim), were determined by more than one analytical method. 

For each of these compounds, QA/QC results and LRLs were 

investigated, and the analytical method judged to provide the 

best performance was selected. Only the results for the selected 

method were included in analyses and discussion related to 

occurrence of OWCs in wastewater effluents and the Big Sioux 

River.

Calculation of Loads

Loads of OWCs were estimated to provide coarse information on sources and fate of OWCs in the Big Sioux River. 

Because non-Lagrangian sampling was conducted, temporal 

correspondence between water samples collected at different 

sampling sites would not be expected. Thus, comparison of 

loads between sites could be affected primarily by diurnal 

variability in wastewater effluent discharges and concentrations 

of OWCs in the wastewater effluent. Loads of OWCs were 

estimated by multiplying discharges at the times of sampling 

by constituent concentrations and by a conversion factor 

(0.0053919) to convert cubic feet per second and micrograms 

per liter to pounds per day. For constituents reported as less than 

the study reporting level (SRL; discussed in the Quality Assurance/Quality Control section), the concentrations were assumed 

to be zero in the load calculations. Load values are reported to 

two significant figures.

The load estimates presented in this report should be used 

with caution. Most of the concentrations of OWCs were very 

small (often near the lower limits of analytical quantitation) and 

reported by the laboratories as estimated values. The multiplication of the concentrations by discharge, which can vary substantially from site to site and for some samples was very large, 

might result in substantially increasing the effect of analytical 

error in the reported load estimates. However, while there might 

be substantial error in the absolute values of the load estimates, 

the load estimates probably provide reasonably accurate estimates for relative comparison between sites and between 

sampling periods. 

Quality Assurance/Quality Control

QA/QC samples were collected to assess precision and 

accuracy of collected data. QA/QC data were used to determine 

which compounds had acceptable method performance and to 

establish SRLs for individual OWCs, as described later in this 

section. QA/QC included both laboratory and field activities.

Laboratory QA/QC included method-blank, reagent-spike, 

and surrogate samples. Method-blank samples consist of 

analyte-free water that is processed and analyzed in the laboratory identically to environmental samples. Reagent-spike 

samples consist of a reagent water sample that is fortified with 

known concentrations of the method analytes. Reagent-spike 

samples are used to monitor the performance of a given analytical method at the time the environmental samples were analyzed. Surrogate compounds are compounds that are similar in 

physical and chemical properties to the method analytes, and 

which are added to all QC and environmental water samples 

prior to analysis. Surrogate compounds are used to monitor the 

accuracy of a given analytical method for a specific environmental matrix. At least one method-blank sample and one 

reagent-spike sample typically are analyzed with each set of 10 

to 15 environmental samples. Surrogates are added to and analyzed for every environmental sample and every QC sample.

Field QA/QC samples included field equipment blanks 

and replicates. For this study, three field equipment-blank samples and three replicate samples were collected and analyzed for 

the laboratory analytical constituents listed in table 10. This 
12 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

level of field QA/QC sampling represents about 22 percent of 

the environmental samples collected and probably is not adequate to fully evaluate the OWC data quality. As a result, field 

equipment blanks, replicates, and environmental matrix spikes 

that were collected during other data-collection activities in the 

Big Sioux River Basin also were analyzed to evaluate OWC 

data quality. These other field QA/QC samples were collected 

during 2002–2004 as part of an investigation of the occurrence 

of OWCs in wastewater effluent and the Big Sioux River in the 

vicinity of Sioux Falls, South Dakota (fig. 1). The samples were 

collected using identical equipment and methods as were used 

in the upper Big Sioux River Basin study, and the matrices 

sampled probably were very similar. Thus, the QA/QC data 

collected in the vicinity of Sioux Falls probably provide OWC 

data-quality information that is representative of the datacollection efforts of the upper Big Sioux River Basin study. 

QA/QC activities for the Sioux Falls study included 5 to 6 field 

equipment blanks (depending on analytical method), 6 to 10 

field replicates (depending on analytical method), and 3 to 10 

environmental matrix spikes (depending on analytical method).

Field equipment-blank samples were collected at field 

sampling sites by passing ultra-pure water through the collection and processing equipment used for environmental samples 

using procedures identical to those used to collect and process 

the environmental samples. A field equipment-blank sample 

with constituent concentrations equal to or less than the SRL for 

a given constituent indicates that the overall process of sample 

collection, processing, and laboratory analysis is free of significant contamination. Sporadic, infrequent detections at concentrations near the SRL probably represent random contamination 

or instrument calibration error that is not persistent in the process and which is not likely to cause significant positive bias in 

study results. Also, consistent detections in the field equipmentblank samples at concentrations that are substantially less than 

concentrations in environmental samples probably indicate 

routine contamination but do not substantially affect study 

results.

Field replicate samples were used to identify the level of 

precision (reproducibility) of analytical results. Field replicate 

samples were collected and processed immediately after each 

associated primary environmental sample was collected and 

processed, and procedures used for replicate samples were identical to those used for primary environmental samples. Field 

replicate samples are considered essentially identical in composition to the primary environmental samples they are associated 

with. Precision of analytical results for field replicate samples 

potentially is affected by numerous sources of variability introduced by both field and laboratory processes, including sample 

collection, sample processing and handling, and laboratory 

preparation and analysis. Analyses of field replicate samples, 

therefore, can indicate the reproducibility of environmental data 

and provide information on the adequacy of procedures to produce consistent results. 

Precision of analytical results for field replicate samples 

was determined by calculating the relative percent difference 

(RPD) for each primary/replicate sample pair as indicated in the 

following equation:

RPD d = ( ) /x *100 (1)

where

d = difference in concentration between the primary 

environmental sample and the field replicate sample 

for a given primary/replicate sample pair, and

x = mean concentration of the primary environmental 

sample and the field replicate sample for a given primary/replicate sample pair.

RPDs were only calculated for primary/replicate sample 

pairs in which a given compound was detected in both samples. 

The number of primary/replicate sample pairs in which a given 

compound was detected in only one of the samples (but not 

both) was noted and also used to assess data quality and establish SRLs. 

Generally, an RPD of 20 percent or less represents an 

acceptable level of precision, although for very small concentrations near the limit of analytical detectability, the percent 

differences can be substantially larger and still be considered 

reasonable due to the limits of resolution (Taylor, 1987). Most 

of the detected concentrations reported in this study are very 

small and near the limit of analytical detectability. Thus, an 

RPD of about 40 percent generally was used in this study to 

determine acceptability of results for field replicate samples. 

Environmental matrix spikes consist of replicate samples 

collected and processed identically to the primary environmental sample that were shipped to the laboratories where they were 

fortified with known concentrations of the method analytes. 

Concentrations of the method analytes in primary environmental samples and the environmental matrix spikes are analyzed to 

determine percent recoveries of analytes. Environmental 

matrix-spike samples are used to monitor the performance of a 

given analytical method for a specific environmental matrix. 

Performance of the analytical methods for individual 

compounds was evaluated by calculating the relative standard 

deviation (RSD, expressed in percent) of the percent recoveries 

of laboratory reagent spikes, laboratory surrogates, and environmental matrix spikes. RSDs were calculated separately for 

laboratory reagent spikes, laboratory surrogates, and environmental matrix spikes. RSDs were computed from the standard 

deviations and the mean concentrations of percent recoveries 

for the spiked samples for a given compound. Expressing precision relative to a mean concentration standardizes comparison 

of precision among individual constituents. The RSD, in 

percent, is calculated according to the following equation:

RSD S = ( ) /X *100 (2)

where

S = standard deviation of percent recoveries of spiked 

samples, and

X = mean of percent recoveries of spiked samples.
Occurrence of Organic Wastewater Compounds 13

In the percent recovery calculations for the various spiked 

samples, any censored values reported as less than the SRL (for 

either the unspiked primary samples or the spiked samples) 

were arbitrarily assigned a value of zero. 

QA/QC results were analyzed in a two-phase process that 

determined acceptability of analytical method performance for 

a given compound and then determined an SRL that generally 

represents the lower level of quantitation at which the compound could be consistently identified and reasonably accurately quantified. Acceptability of method performance for a 

given compound was determined by analysis of percent recoveries for laboratory reagent spikes, laboratory surrogates, and 

environmental matrix spikes. Method performance was determined to be acceptable when the median percent recoveries for 

laboratory reagent spikes, laboratory surrogates, and environmental matrix spikes were between 30 to 120 percent, and the 

percent recovery RSDs for laboratory reagent spikes, laboratory 

surrogates, and environmental matrix spikes were less than 

40 percent. Individual compounds that did not meet these 

method-performance acceptability criteria generally were 

excluded from analyses and discussion related to occurrence of 

OWCs in wastewater effluent and the Big Sioux River. The 

compounds 5-methyl-1H-benzotriazole and beta-sitosterol had 

median percent recoveries for environmental matrix spikes of 

140 and 160 percent, respectively, which exceeded the methodperformance acceptability criterion of 120 percent. However, 

because these compounds had relatively small percent recovery 

RSDs for environmental matrix spikes (about 20 percent) and 

all other QA/QC results were acceptable, method performance 

for these compounds was determined to be acceptable.

For compounds that had acceptable method performance 

for laboratory reagent spikes and environmental matrix spikes, 

analytical results for laboratory method blanks, field equipment 

blanks, and field replicate samples were analyzed to determine 

SRLs. SRLs were established to identify the lower levels of 

quantitation at which the compounds could be consistently 

identified by the analysts and reasonably accurately quantified 

without being substantially influenced by routine contamination resulting from either laboratory or field activities. For each 

compound, the SRL was established such that the compound 

was consistently detected in both samples of primary/replicate 

sample pairs with acceptable variability (median RPD generally 

less than 40 percent); the SRL generally was substantially 

larger than levels of contamination detected in laboratory 

method blanks and field equipment blanks. Generally, compounds that were determined to have acceptable QA/QC had 

median RPDs for field replicate samples less than 40 percent. 

The compounds acetophenone and nonylphenol monoethoxylate (NP1EO) had median RPDs of 50 and 44 percent, respectively. However, because all other QA/QC results for these 

compounds were acceptable, they were included in analyses 

and discussion related to occurrence of OWCs in wastewater 

effluent and the Big Sioux River.

Analytical results for laboratory method blanks, laboratory 

reagent spikes, laboratory surrogate samples, field equipment 

blanks, field replicate samples, and environmental matrix 

spikes are summarized in tables 11–16, respectively, in the 

Supplemental Information section. Information concerning 

compounds excluded from data analysis due to unacceptable 

method performance, and the established SRLs for compounds 

with acceptable method performance are summarized in 

table 10. Of the 125 different OWCs analyzed for in this study, 

73 OWCs had one or more detections in environmental samples 

reported by the laboratories, and of those 73 OWCs, 45 had 

acceptable analytical method performance, were detected at 

concentrations greater than the SRLs, and were included in 

analyses and discussion related to occurrence of OWCs in 

wastewater effluents and the Big Sioux River.

Occurrence of Organic Wastewater

Compounds

This section of the report summarizes the occurrence of 

OWCs in wastewater effluent and the Big Sioux River in the 

vicinity of three cities—Watertown, Volga, and Brookings. In 

addition to presenting analytical results of OWCs, results for 

field measured properties and constituents and auxiliary constituents are included. Wastewater discharges and flow conditions 

in the Big Sioux River at the time of sampling also are 

described.

Results for field measured properties and constituents 

and auxiliary constituents are given in table 17 in the Supplemental Information section. Laboratory analytical results for 

HPCs, HVACs, MAHs, HIACs, PAHs, and SCs are given in 

tables 18–23, respectively, in the Supplemental Information 

section and are reported exactly as received from the laboratory. 

It should be noted that for some compounds the established 

SRLs were larger than some of the detected concentrations 

reported by the laboratories. Thus, some of the reported 

detected concentrations in tables 18–23 were censored at the 

SRLs for the purposes of data analysis and summary.

Summary calculations for OWCs, including total and 

median concentrations for compound classes, are rounded to 

two significant figures. However, illustrations were created 

using unrounded raw values. Thus, there might be very small 

differences between values reported in text/tables and those 

shown in illustrations.
14 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Watertown Area Results

Sites in the Watertown area were sampled during August 

18–20, 2003, when low-flow conditions prevailed and during 

June 15–16, 2004, when runoff conditions prevailed. Flow conditions during sampling periods are shown in figure 3. During 

August 18–20, 2003, streamflow at long-term USGS gaging 

station 06479525, located about 14 river miles downstream 

from sampling site WT-DS2, was about 18 percent of the 

long-term (1976–2004) median mid-August flow. During 

June 15–16, 2004, streamflow at station 06479525 was about 

110 percent of the long-term median mid-June flow. The 

Watertown WWTP discharged continuously to the Big Sioux 

River during both sampling periods. During the August 2003 

sampling period, the Watertown WWTP discharge accounted 

for about 50 to 95 percent of the flow of the Big Sioux River 

from the confluence of the WWTP discharge to about 5 mi 

downstream. During the June 2004 sampling period, the Watertown WWTP discharge accounted for about 10 to 50 percent of 

the flow of the Big Sioux River from the confluence of the 

WWTP discharge to about 5 mi downstream.

Field-Measured Properties and Constituents and 

Auxiliary Constituents

Results for field-measured properties and constituents and 

auxiliary constituents in samples from sites in the Watertown 

area are presented in table 17 and figure 4. Generally, results for 

field-measured properties and constituents and auxiliary constituents for the Watertown area are within typical ranges for the 

upper Big Sioux River Basin (East Dakota Water Development 

District, 2004).

0.1

1

10

100

1,000

17 18 19 20 21

AUGUST 2003

DISCHARGE, IN CUBIC FEET PER SECOND

Streamflow at WT-US1 (station 06479500)

Streamflow at WT-US2 (station 06479512)

Streamflow at WT-DS2 (station 06479520)

WT-US1 sample collected

WT-US2 sample collected

WT-DS2 sample collected

WT-WWE sample collected

WT-DS1 sample collected

Streamflow at station 06479525

WT-WWE discharge

0.1

1

10

100

1,000

14 15 16 17

JUNE 2004

August 18-20, 2003 June 15-16, 2004

EXPLANATION

Figure 3. Flow conditions during sampling periods for sites in the Watertown area.
0

5

10

15

20

25

30

35

40

DISCHARGE, IN CUBIC FEET PER SECOND

0

5

10

15

20

25

30

35

40

0

5

10

15

20

25

30

35

40

TURBIDITY, IN NEPHELOMETRIC TURBIDITY UNITS

0

5

10

15

20

25

30

35

40

0

2

4

6

8

10

12

16

14

18

20

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

DISSOLVED OXYGEN, IN MILLIGRAMS PER LITER

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

August 18-20, 2003 June 15-16, 2004

SITE LABEL SITE LABEL

Turbidity

data not

collected

0

2

4

6

8

10

12

16

14

18

20

Occurrence of Organic Wastewater Compounds 15

Figure 4. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and 

the Big Sioux River in the Watertown area.
0

2

4

6

8

10

12

14

pH, IN STANDARD UNITS

SPCIFIFC CONDUCTANCE,

IN MICROSIEMENS PER CENTIMETER

AT 25 DEGREES CELSIUS

0

5

10

15

20

25

30

WATER TEMPERATURE, IN DEGREES CELSIUS

August 18-20, 2003 June 15-16, 2004

SITE LABEL SITE LABEL

0

2

4

6

8

10

12

14

0

200

400

600

800

1,000

1,200

1,400

0

200

400

600

800

1,000

1,200

1,400

0

5

10

15

20

25

30

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2 WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

16 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 4. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the Big 

Sioux River in the Watertown area.—Continued
0

5

10

15

20

NITRITE PLUS NITRATE NITROGEN,

IN MILLIGRAMS PER LITER

TOTAL COLIFORM BACTERIA,

IN COLONIES PER 100 MILLILITERS

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2 WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

FECAL COLIFORM BACTERIA,

IN COLONIES PER 100 MILLILITERS

August 18-20, 2003 June 15-16, 2004

SITE LABEL SITE LABEL

0

2,000

4,000

6,000

8,000

10,000

12,000

20,000

14,000

16,000

18,000

0

2,000

4,000

6,000

8,000

10,000

12,000

20,000

14,000

16,000

18,000

Note: WT-DS1 extends to 50,000

0

200

400

600

800

1,000

1,200

2,000

1,400

1,600

1,800

0

200

400

600

800

1,000

1,200

2,000

1,400

1,600

1,800

0

5

10

15

20

Concentration less than laboratory reportinglevel (0.06 mg/L)Concentration less than laboratory reportinglevel (0.06 mg/L)Concentration less than laboratory reportinglevel (0.06 mg/L)

Occurrence of Organic Wastewater Compounds 17

Figure 4. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the 

Big Sioux River in the Watertown area.—Continued
18 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Organic Wastewater Constituents

OWCs in all compound classes were detected in water 

samples from sampling sites in the Watertown area (fig. 5, 

tables 4 and 5). Total OWC concentrations for upstream Big 

Sioux River sites generally were small, about 6 μg/L for August 

2003 and about 0.2 μg/L for June 2004. 

SCs accounted for nearly all of the total OWC concentration for upstream Big Sioux River sites (WT-US1 and 

WT-US2) for August 2003, and MAHs accounted for nearly all 

of the total OWC concentrations for June 2004. Total OWC 

concentrations for WT-WWE were relatively large for both 

August 2003 and June 2004 (about 41 and 20 μg/L, respectively). Major OWC classes contributing to total OWC concentrations for WT-WWE included HIACs, SCs, and HVACs. 

HIACs accounted for about 78 and 32 percent, SCs accounted 

for about 13 and 20 percent, and HVACs accounted for about 

10 and 45 percent of the total OWC concentrations for the 

August 2003 and June 2004 WT-WWE samples, respectively. 

Total OWC concentrations for WT-DS1 were relatively large 

for August 2003 (about 19 μg/L) and smaller for June 2004 

(about 6.5 μg/L). Major OWC classes contributing to total 

OWC concentrations for WT-DS1 were HIACs, SCs, and 

HVACs. HIACS accounted for about 74 and 46 percent, SCs 

accounted for about 19 and 28 percent, and HVACs accounted 

for 6 and 23 percent of total OWC concentrations for August 

2003 and June 2004, respectively. Total OWC concentrations 

were smaller for WT-DS2 (about 6.9 and 3.3 μg/L for August 

2003 and June 2004, respectively) than for WT-WWE and 

WT-DS1. In a larger scale but similarly designed study, Glassmeyer and others (2005) reported similar decreases in total 

OWC concentrations moving in a downstream direction from 

WWTP effluent discharges. Major OWC classes contributing to 

total OWC concentrations for WT-DS2 were SCs, HIACs, and 

HVACs. SCs accounted for about 70 and 45 percent, HIACS 

accounted for 17 and 29, and HVACs accounted for 12 and 

18 percent of total OWC concentrations for August 2003 and 

June 2004, respectively. For both August 2003 and June 2004, 

concentrations and loads of HIACs were smaller for WT-DS2 

than for WT-DS1, and SCs accounted for a larger proportion of 

the total OWC concentration and load for WT-DS2 than for 

WT-DS1. This might be due to (1) contribution of SCs from 

nonpoint livestock agricultural and/or human wastewater 

sources between WT-DS1 and WT-DS2; (2) degradation of 

HIACs in the Big Sioux River; (3) adsorption of HIACs to 

particulate material and sedimentation from the water column; 

(4) diurnal variability in wastewater effluent discharges and 

concentrations of OWCs in the wastewater effluent combined 

with effects of non-Lagrangian sampling; and (5) dilution 

effects decreasing concentrations of individual HIACs below 

detectable concentrations. Although confident conclusions cannot be made primarily due to possible effects of non-Lagrangian 

sampling, OWC results for the Watertown area might indicate 

that (1) OWCs for upstream Big Sioux River sites probably 

were contributed by nonpoint agricultural sources, with nonpoint livestock agricultural accounting for most of the total 

OWC concentration for the August 2003 (low-flow) sampling 

period, and crop agriculture accounting for most of the total 

OWC concentration for the June 2004 (runoff) sampling period; 

(2) OWCs for downstream Big Sioux River sites were strongly 

influenced by contributions from the Watertown WWTP during 

both the August 2003 (low-flow) and June 2004 (runoff) sampling periods; and (3) contributions of OWCs from nonpoint 

livestock agricultural and/or human wastewater sources (other 

than the Watertown WWTP wastewater effluent discharge) 

accounted for a larger proportion of OWCs for WT-DS2 than 

for WT-DS1 for both the August 2003 (low-flow) and June 

2004 (runoff) sampling periods.

HPCs were detected in samples collected from all sites in 

the Watertown area (fig. 5, tables 4 and 5). One HPC (cotinine) 

was detected in samples collected from the upstream sites 

WT-US1 and WT-US2 at estimated concentrations less than 

0.01 μg/L and accounted for about 0.1 percent of the total OWC 

concentrations. Three HPCs (cotinine, dehydronifedipine, 

and salbumatol) were detected in samples collected from 

WT-WWE with combined estimated concentrations less than 

0.1 μg/L and accounted for no more than about 0.3 percent of 

the total OWC concentration for any sample. Four HPCs were 

detected in samples collected from the downstream sites 

WT-DS1 and WT-DS2 with total estimated concentrations less 

than 0.15 μg/L, which accounted for no more than about 

1 percent of the total OWC concentration for any sample.

HVACs were not detected in any samples collected from 

upstream sites WT-US1 and WT-US2, but HVACs were 

detected in samples collected from WT-WWE and downstream 

sites WT-DS1 and WT-DS2 (fig. 5, tables 4 and 5). Ten 

HVACs were detected in samples from WT-WWE. Erythromycin, erythromycin-H2O, and sulfamethoxazole had the largest 

concentrations (maxima of 1.3, 5.7, and 1.2 μg/L, respectively). 

Total HVAC concentrations were about 4 and 9 μg/L, which 

accounted for about 10 and 45 percent of the total OWC for the 

August 2003 and June 2004 samples, respectively. Eight 

HVACs were detected in samples from WT-DS1 and WT-DS2 

with total estimated HVAC concentrations ranging from 0.59 to 

1.5 μg/L. Erythromycin-H2O and sulfamethoxazole had the 

largest concentrations (maxima of 0.56 and 0.85 μg/L, respectively, at WT-DS1). For the WT-DS1 samples, total estimated 

HVAC concentrations were 1.1 and 1.5 μg/L, which accounted 

for about 6 and 23 percent of the total OWC concentration for 

the August 2003 and June 2004 samples, respectively. For the 

WT-DS2 samples, total HVAC concentrations were 0.83 and 

0.59 μg/L, and accounted for about 12 and 18 percent of the 

total OWC concentration for the August 2003 and June 2004 

samples, respectively. The increase in numbers of HVACs 

detected and total HVAC concentrations for the June 2004 

sample relative to the August 2003 sample might be related to 

changes in the analytical method that substantially reduced the 

LRLs for HVACs. 
NUMBER OF COMPOUNDS DETECTED

0

5

10

15

20

25

30

35

45

40

CONCENTRATION, IN MICROGRAMS PER LITER

0

0.5

1.0

1.5

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

LOAD, IN POUNDS PER DAY

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

August 18-20, 2003 June 15-16, 2004

SITE LABEL SITE LABEL

0

5

10

15

20

25

30

35

0

5

10

15

20

25

30

35

0

5

10

15

20

25

30

35

45

40

0

0.5

1.0

1.5

EXPLANATION

Sterol compounds (SCs)

Polyaromatic hydrocarbons (PAHs)

Household, industrial, and minor agricultural

 use compounds (HIACs)

Major agricultural herbicides (MAHs)

Human and veterinary antibiotic compounds (HVACs)

Human pharmaceutical compounds (HPCs)

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound

 class represents the amount that compound class contributes to the total

Occurrence of Organic Wastewater Compounds 19

Figure 5. Summary of results for organic wastewater compounds in wastewater effluent and the Big Sioux River in the 

Watertown area.
Table 4. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux RivWatertown area.[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated]

Station identification number and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River at 

Broadway, at

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent, 

near Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004 Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730 

Human pharmaceutical compounds (HPCs)

Number of compounds detected 1 0 1 0 3 2 3 1 Minimum detected concentration (μg/L) e0.0047 0 e0.0027 0 e0.0035 0.017 e0.0054 e0.0066 Median detected concentration (μg/L) e0.0047 0 e0.0027 0 0.034 0.026 0.039 e0.0066 Maximum detected concentration (μg/L) e0.0047 0 e0.0027 0 0.049 0.036 0.087 e0.0066 Total detected concentration (μg/L) e0.0047 0 e0.0027 0 e0.086 0.053 e0.13 e0.0066 Total load (lb/d) e0.0000 0 e0.0000 0 e0.0023 e0.0017 e0.0042 e0.0006 

Human and veterinary antibiotic compounds (HVACs)

Number of compounds detected 0 0 0 0 4 10 3 6 Minimum detected concentration (μg/L) 0 0 0 0 0.17 0.016 0.27 0.036 Median detected concentration (μg/L) 0 0 0 0 1.1 0.26 0.31 0.16 Maximum detected concentration (μg/L) 0 0 0 0 1.7 5.7 0.56 0.85 Total detected concentration (μg/L) 0 0 0 0 4.0 9.0 1.1 1.5 Total load (lb/d) 0 0 0 0 e0.11 e0.30 e0.036 e0.14 

Major agricultural herbicides (MAHs)

Number of compounds detected 1 1 0 1 1 1 1 1 Minimum detected concentration (μg/L) e0.10 e0.21 0 0.19 0.068 0.18 0.10 0.16 Median detected concentration (μg/L) e0.10 e0.21 0 0.19 0.068 0.18 0.10 0.16 Maximum detected concentration (μg/L) e0.10 e0.21 0 0.19 0.068 0.18 0.10 0.16 Total detected concentration (μg/L) e0.10 e0.21 0 0.19 0.068 0.18 0.10 0.16 Total load (lb/d) e0.0002 e0.025 0 e0.0090 e0.0018 e0.0059 e0.0032 e0.014 
Household, industrial, and minor agricultural use compounds (HIACs)

Number of compounds detected 4 0 3 0 15 13 13 9 Minimum detected concentration (μg/L) e0.036 0 e0.046 0 e0.034 e0.063 e0.024 e0.054 Median detected concentration (μg/L) e0.080 0 e0.35 0 e0.15 e0.35 e0.11 e0.35 Maximum detected concentration (μg/L) e0.19 0 0.55 0 28 1.6 12 e0.84 Total detected concentration (μg/L) e0.39 0 e0.95 0 e32 e6.3 e14 e3.0 Total load (lb/d) e0.0009 0 e0.0023 0 e0.83 e0.21 e0.46 e0.27 

Polyaromatic hydrocarbons (PAHs)

Number of compounds detected 0 0 0 1 0 0 0 0 Minimum detected concentration (μg/L) 0 0 0 e0.014 0 0 0 0 Median detected concentration (μg/L) 0 0 0 e0.014 0 0 0 0 Maximum detected concentration (μg/L) 0 0 0 e0.014 0 0 0 0 Total detected concentration (μg/L) 0 0 0 e0.014 0 0 0 0 Total load (lb/d) 0 0 0 e0.0007 0 0 0 0 

Sterol compounds (SCs)

Number of compounds detected 2 0 2 0 3 2 3 1 Minimum detected concentration (μg/L) 2.2 0 e1.6 0 e0.94 e1.2 e0.94 e1.8 Median detected concentration (μg/L) 2.7 0 e1.7 0 e1.3 e2.0 e1.0 e1.8 Maximum detected concentration (μg/L) 3.2 0 e1.8 0 3.0 2.9 e1.7 e1.8 Total detected concentration (μg/L) 5.4 0 e3.4 0 e5.2 e4.1 e3.6 e1.8 Total load (lb/d) e0.013 0 e0.0084 0 e0.14 e0.13 e0.12 e0.16 

Table 4. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux RivWatertown area.—Continued[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated]

Station identification number and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River at 

Broadway, at

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent, 

near Watertown, SD

(WT-DS1)
All organic wastewater compounds (OWCs)

Number of compounds detected 8 1 6 2 26 28 23 18 Minimum detected concentration (μg/L) e0.0047 e0.21 e0.0027 e0.014 e0.0035 0.016 e0.0054 e0.0066 Median detected concentration (μg/L) e0.10 e0.21 e0.45 e0.10 e0.18 e0.32 e0.18 e0.19 Maximum detected concentration (μg/L) 3.2 e0.21 e1.8 e0.19 28 5.7 12 e1.8 Total detected concentration (μg/L) e5.9 e0.21 e4.3 e0.20 e41 e20 e19 e6.5 Total load (lb/d) e0.014 e0.025 e0.011 e0.0097 e1.1 e0.65 e0.62 e0.58 

Endocrine-disrupting compounds (EDCs) from all compound classes

Number of compounds detected 2 1 1 1 4 7 4 6 Minimum detected concentration (μg/L) e0.10 e0.21 0.55 e0.19 e0.078 e0.091 e0.068 e0.060 Median detected concentration (μg/L) e0.14 e0.21 0.55 e0.19 e0.17 e0.54 e0.10 e0.45 Maximum detected concentration (μg/L) e0.19 e0.21 0.55 e0.19 1.1 1.6 0.59 e0.84 Total detected concentration (μg/L) e0.29 e0.21 0.55 e0.19 e1.4 e4.3 e0.86 e2.5 Total load (lb/d) e0.0007 e0.025 e0.0014 e0.0090 e0.040 e0.14 e0.027 e0.22 

Table 4. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux RivWatertown area.—Continued[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated]

Station identification number and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River at 

Broadway, at

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent, 

near Watertown, SD

(WT-DS1)
Table 5. Detected organic wastewater compounds in wastewater effluent and the Big Sioux River in the Watertown area.[Bold text for compound names indicates suspected endocrine-disrupting compounds (EDCs). AHTN, 7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydronaphthalene; DEET, N,N-diethHHCB, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl cyclopenta-g-2-benzopyran; NP2EO, nonylphenol diethoxylate; NP1EO, nonylphenol monoethoxylate; NP, para-nonylph

Station identification number and name (site label)

06479500

Big Sioux River

at Watertown, SD

(WT-US1)

06479512

Big Sioux River at Broadway,

at Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below

wastewater effluent,

near Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004 Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730 Number of compounds 

detected

8 1 6 2 26 28 23 18 

Human pharmaceutical 

compounds (HPCs)

Cotinine -- Cotinine -- Cotinine

DehydronifedipineSalbutamol

CotinineSalbutamol

CaffeineCotinineSalbutamol

Cotinine Co

De

e

Sa

Human and veterinary 

antibiotic compounds (HVACs)

-- -- -- -- Ciprofloxacin

ErythromycinH2OOfloxacinSulfamethoxazole

CiprofloxacinErythromycinErythromycinH2ONorfloxacinOfloxacinRoxithromycinSulfadiazineSulfamethoxazoleTetracyclineTrimethoprim

ErythromycinH2OOfloxacinSulfamethoxazole

CiprofloxacinErythromycinErythromycinH2OOfloxacinSulfamethoxazoleTrimethoprim

Er

H

Su

a

Major agricultural 

herbicides (MAHs)

Atrazine Atrazine -- Atrazine Prometon Atrazine Prometon Atrazine Pr
Household, industrial, and 

minor agricultural-use compounds (HIACs)

Bisphenol-AN,N-diethylmetatoluamide 

(DEET)

IndoleIsophorone

-- Diethyl 

phthalate

Tributyl 

phosphate

Tri(2-

butoxyethyl)

phosphate

-- 5-methyl-1Hbenzotriazole

AHTNAcetophenoneBenzophenoneDEETHHCBIndolepara-cresolTributyl 

phosphate

TriclosanTriethyl citrate 

(ethyl citrate)

Triphenyl 

phosphate

Tri(2-

butoxyethyl)

phosphate

Tri(2-chloroethyl)phosphateTri(dichloroisopropyl)phosphate

5-methyl-1HbenzotriazoleAHTNBenzophenoneDEETHHCBNP2EONP1EONPTributyl 

phosphate

Triethyl citrate 

(ethyl citrate)

Triphenyl 

phosphate

Tri(2-

chloroethyl)

phosphate

Tri(dichloroisopropyl)phosphate

AHTNAcetophenoneBenzophenoneDEETHHCBIndoleTributyl 

phosphate

TriclosanTriethyl citrate 

(ethyl citrate)

Triphenyl 

phosphate

Tri(2-

butoxyethyl)

phosphate

Tri(2-

chloroethyl)

phosphate

Tri(dichloroisopropyl)phosphate

AHTNHHCBNP2EONP1EONPTributyl 

phosphate

Triethyl citrate 

(ethyl citrate)

Tri(2-

butoxyethyl)

phosphate

Tri(2-

chloroethyl)

phosphate

AHAcBeBiDEHInTr

p

TrTr

b

p

Tr

c

p

Tr

pp

PAH compounds (PAHs) -- -- -- Naphthalene -- -- -- -- Sterol compounds (SCs) beta-sitosterol

Cholesterol

-- beta-sitosterol

Cholesterol

-- 3-betacoprostanol

beta-sitosterolCholesterol

3-betacoprostanolCholesterol

3-betacoprostanolbeta-sitosterolCholesterol

Cholesterol 3-

c

beCh

Table 5. Detected organic wastewater compounds in wastewater effluent and the Big Sioux River in the Watertown area.—Continued[Bold text for compound names indicates suspected endocrine-disrupting compounds (EDCs). AHTN, 7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydronaphthalene; DEET, N,N-dieth

HHCB, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl cyclopenta-g-2-benzopyran; NP2EO, nonylphenol diethoxylate; NP1EO, nonylphenol monoethoxylate; NP, para-nonylph

Station identification number and name (site label)

06479500

Big Sioux River

at Watertown, SD

(WT-US1)

06479512

Big Sioux River at Broadway,

at Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below

wastewater effluent,

near Watertown, SD

(WT-DS1)
Occurrence of Organic Wastewater Compounds 25

MAHs were detected in samples collected from all sampling sites in the Watertown area (fig. 5, tables 4 and 5). Atrazine was detected in samples collected from the upstream sites 

WT-US1 and WT-US2 at estimated concentrations less than 

0.2 μg/L and accounted for less than about 2 percent of the total 

OWC concentrations for August 2003 samples collected from 

these sites, but between about 95 and 100 percent for June 2004 

samples. Two MAHs (atrazine and prometon) were detected in 

samples collected from WT-WWE with total estimated concentrations less than 0.2 μg/L, which accounted for less than about 

1 percent of the total OWC concentration for any WT-WWE 

sample. The same two MAHs (atrazine and prometon) were 

detected in samples collected from the downstream sites WTDS1 and WT-DS2 with total concentrations less than 0.3 μg/L, 

which accounted for less than about 8 percent of any sample. 

MAH concentrations at all sampling sites in the Watertown area 

were larger in June 2004 samples than in August 2003 samples.

HIACs were detected in samples from all sites in the 

Watertown area (fig. 5, tables 4 and 5). Seven HIACs were 

detected in samples from the upstream sites WT-US1 and 

WT-US2 with combined estimated concentrations as large as 

0.95 μg/L. Bisphenol-A, diethyl phthalate, and tri(2-butoxyethyl)phosphate had the largest concentrations for the upstream 

sites, with maximum estimated concentrations of 0.19, 0.55, 

and 0.35 μg/L, respectively. All other individual HIACs had 

detected concentrations less than 0.2 μg/L. Total HIAC concentrations accounted for about 0 to 22 percent of the total OWC 

concentrations for the upstream sites. Eighteen HIACs were 

detected in samples from WT-WWE. For the August 2003 

WT-WWE sample, 7-acetyl-1,1,2,4,4,6-hexamethyl tetrahydronaphthalene (AHTN) and tri(2-chloroethyl)phosphate had 

the largest concentrations (1.1 and 28 μg/L, respectively), and 

detected concentrations of all other individual HIACs were less 

than 0.5 μg/L. The total estimated HIAC concentration for the 

August 2003 WT-WWE sample was 32 μg/L and accounted for 

about 78 percent of the total OWC concentration. For the June 

2004 WT-WWE sample, 5-methyl-1H-benzotriazole, AHTN, 

nonylphenol diethoxylate (NP2EO), NP1EO, and para-nonylphenol (NP) had the largest concentrations (about 0.89, 1.6, 

0.91, 0.54, and 0.84 μg/L, respectively), and detected concentrations of all other individual HIACs were less than about 

0.4 μg/L. The total HIAC concentration for the August 2003 

WT-WWE sample was about 6.3 μg/L and accounted for about 

32 percent of the total OWC concentration. Seventeen HIACs 

were detected in samples collected from the downstream sites 

WT-DS1 and WT-DS2 with total estimated HIAC concentrations ranging from 0.95 to 14 μg/L. For August 2003, HIACs 

with largest estimated concentrations included AHTN, tri(2-

butoxyethyl)phosphate, and tri(2-chloroethyl)phosphate (0.59, 

0.63, and 12 μg/L, respectively) for WT-DS1 and tri(2-butoxyethyl)phosphate, tri(2-chloroethyl)phosphate, and tri(dichloroisopropyl)phosphate (0.23, 0.20, and 0.18 μg/L, respectively) 

for WT-DS2. For August 2003, total HIAC concentrations 

accounted for about 74 and 17 percent of the total OWC concentrations for WT-DS1 and WT-DS2, respectively. For June 

2004, HIACs with largest estimated concentrations included 

AHTN, NP2EO, NP1EO, and NP (0.51, 0.55, 0.39, and 

0.84 μg/L, respectively) for WT-DS1 and AHTN (0.16 μg/L) 

for WT-DS2. Concentrations of HIACs in samples collected 

from downstream sites were larger during August 2003 than 

during June 2004 and probably reflect a greater fraction of the 

total flow of the Big Sioux River being derived from WWTP 

discharge during the August 2003 sampling period. For both 

August 2003 and June 2004, concentrations and loads of HIAC 

compounds were substantially smaller for WT-DS2 than for 

WT-DS1. This might be due to (1) degradation of OWCs in the 

Big Sioux River; (2) adsorption of OWCs to particulate material 

and sedimentation from the water column; (3) diurnal variability in wastewater effluent discharges and concentrations of 

OWCs in the wastewater effluent combined with effects of nonLagrangian sampling; and (4) dilution that can directly reduce 

concentrations and can possibly reduce load estimates by 

decreasing concentrations to less than detectable levels.

One PAH (naphthalene) was detected in a single sample 

(June 2004) collected from a single site (WT-US2) in the 

Watertown area at an estimated concentration of 0.014 μg/L. 

The detection accounted for about 7 percent of the total OWC 

concentration for that sample.

SCs were detected in samples from all sites in the Watertown area (fig. 5, tables 4 and 5). Two SCs (beta-sitosterol and 

cholesterol) were detected in August 2003 samples collected 

from the upstream sites WT-US1 and WT-US2. No SCs were 

detected in June 2004 samples from the upstream sites. Total 

estimated SC concentrations were 5.4 and 3.4 μg/L, and 

accounted for about 92 and 79 percent of the total OWC concentration for the August 2003 WT-US1 and WT-US2 samples, 

respectively. Three SCs (3-beta-coprostanol, beta-sitosterol, 

and cholesterol) were detected in samples collected from 

WT-WWE (table 5). Total estimated SC concentrations were 

5.2 and 4.1 μg/L, which accounted for about 13 and 20 percent 

of the total OWC concentration for the August 2003 and June 

2004 WT-WWE samples, respectively. The same three SCs 

(3-beta-coprostanol, beta-sitosterol, and cholesterol) were 

detected in samples collected from downstream sites WT-DS1 

and WT-DS2. Total estimated SC concentrations were 3.6 and 

1.8 μg/L, and accounted for about 19 and 28 percent of the total 

OWC concentrations for the August 2003 and June 2004 WTDS1 samples, respectively. Total estimated SC concentrations 

were 4.8 and 1.5 μg/L, and accounted for about 70 and 

45 percent of the total OWC concentrations for the August 2003 

and June 2004 WT-DS2 samples, respectively. SC loads for 

both WT-DS1 and WT-DS2 were larger for the June 2004 

samples than for the August 2003 samples, primarily due to 

larger streamflow during the June sampling.

EDCs were detected in all samples from sampling sites in 

the Watertown area (fig. 6, tables 4 and 5). For both August 

2003 and June 2004, the numbers of EDCs detected, and EDC 

concentrations and loads generally were larger for WT-WWE 

and downstream sites in the Watertown area (WT-DS1 and 

WT-DS2) than for upstream sites (WT-US1 and WT-US2). 

Three EDCs were detected in samples collected from upstream 

sites (atrazine, an MAH; and bisphenol-A and diethyl phthalate, 

HIACs). Total estimated EDC concentrations ranged from 0.19 
NUMBER OF COMPOUNDS DETECTED CONCENTRATION, IN MICROGRAMS PER LITER

0

0.10

0.05

0.20

0.25

0.15

0.30

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

LOAD, IN POUNDS PER DAY

WT-US1 WT-US2 WT-WWE WT-DS1 WT-DS2

August 18-20, 2003 June 15-16, 2004

SITE LABEL SITE LABEL

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

0

0.5

1.0

1.5

2.0

2.5

5.0

4.5

3.0

3.5

4.0

0

0.10

0.05

0.20

0.25

0.15

0.30

0

0.5

1.0

1.5

2.0

2.5

5.0

4.5

3.0

3.5

4.0

EXPLANATION

Major agricultural herbicides (MAHs)—Suspected

 of being endocrine disrupting compounds

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound

 class represents the amount that compound class contributes to the total

Suspected endocrine disrupting compounds—From all

 compound classes (excluding major agricultural

 herbicides)

26 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 6. Summary of results for endocrine-disrupting compounds (EDCs) from all compound classes in wastewater effluent and 

the Big Sioux River in the Watertown area.
Occurrence of Organic Wastewater Compounds 27

to 0.55 μg/L for upstream sites and were larger for August 2003 

samples than for June 2004 samples. HIACs accounted for most 

of the total EDC concentration for August 2003, and an MAH 

(atrazine) accounted for all of the total EDC concentration for 

June 2004. Eight EDCs were detected in samples collected from 

WT-WWE (atrazine, an MAH; and AHTN, benzophenone, 

1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl cyclopenta-g-2-

benzopyran (HHCB), NP2EO, NP1EO, NP, and triclosan, 

which are HIACs). Total estimated EDC concentrations for 

WT-WWE were 1.4 and 4.3 μg/L for August 2003 and June 

2004, respectively. HIACs accounted for more than about 

96 percent of the total EDC concentration for WT-WWE 

samples. Nine EDCs were detected in samples collected from 

downstream sites (atrazine, an MAH; and AHTN, benzophenone, bisphenol-A, HHCB, triclosan, NP2EO, NP1EO, and NP, 

which are HIACs). Total estimated EDC concentrations were 

0.86 and 2.5 μg/L for WT-DS1, and 0.32 and 0.46 μg/L for 

WT-DS2, for August 2003 and June 2004, respectively. Of the 

total EDC concentration, MAHs accounted for about 0 and 

6 percent for WT-DS1, and for about 0 and 57 percent for 

WT-DS2 for August 2003 and June 2004, respectively. Of the 

total EDC concentration, HIACs accounted for about 100 and 

94 percent for WT-DS1, and for about 100 and 43 percent for 

WT-DS2 for August 2003 and June 2004, respectively.

Volga Area Results

Sites in the Volga area were sampled during August 20–

21, 2003, and October 21–22, 2003, when generally low-flow 

conditions prevailed, and during June 16–17, 2004, when runoff conditions prevailed. The Volga WWTP was not discharging to the Big Sioux River during the August 2003 or June 2004 

sampling periods. Flow conditions during sampling periods are 

shown in figure 7. During August 20–22, 2003, streamflow at 

long-term USGS gaging station 06480000, located about 16 

river miles downstream from sampling site VL-DS2/BK-US1, 

was about 32 percent of the long-term (1953–2004) median 

mid-August flow. During October 21–22, 2003, streamflow at 

station 06480000 was about 31 percent of the long-term median 

mid-October flow. During the October 2003 sampling period, 

the Volga WWTP was discharging continuously to the Big 

Sioux River, and the Volga WWTP discharge accounted for 

about 5 percent of the flow of the Big Sioux River from the confluence of the WWTP discharge to several miles downstream. 

During June 16–18, 2004, streamflow at station 06480000 was 

about 150 percent of the long-term median mid-June flow.

Field-Measured Properties and Constituents

Results for field-measured properties and constituents and 

auxiliary constituents in samples from sites in the Volga area 

are presented in figure 8 and table 17. Generally, results for 

field-measured properties and constituents and auxiliary constituents for the Volga area were within typical ranges for the 

upper Big Sioux River Basin (East Dakota Water Development 

District, 2004).

Organic Wastewater Constituents

OWCs in all compound classes except PAHs were 

detected in samples from sampling sites in the Volga area 

(fig. 9, tables 6 and 7). Differences in total OWC concentrations and loads between the upstream Big Sioux River site 

(VL-US1) and downstream sites (VL-DS1 and VL-DS2/

BK-US1) were variable. For August 2003, the upstream site had 

larger total OWC concentrations and loads than downstream 

sites. SCs and HIACs accounted for about 90 percent and 

8 percent, respectively, of the August 2003 VL-US1 total OWC 

concentration. SCs accounted for about 94 percent of the 

August 2003 VL-DS1 total OWC concentration, and SCs and 

HIACS accounted for about 83 and 10 percent, respectively, of 

the August 2003 VL-DS2/BK-US1 total OWC concentration. 

For October 2003, when the Volga WWTP was discharging to 

the Big Sioux River channel, total OWC concentrations and 

loads were larger for VL-DS1 than for VL-US1, and the estimated increase in load between VL-US1 and VL-DS1 corresponds well with the estimated load contributed by VL-WWE, 

especially for HIACs. HIACs and SCs accounted for about 64 

and 33 percent, respectively, of the October 2003 VL-US1 total 

OWC concentration, and about 52 and 45 percent of the October 2003 VL-DS1 concentration. For June 2004, VL-US1 had a 

smaller total OWC concentration and load than downstream 

Big Sioux River sites. MAHs accounted for 90, 84, and 

86 percent of the June 2004 total OWC concentrations for 

VL-US1, VL-DS1, and VL-DS2/BK-US1, respectively. 

Although confident conclusions cannot be made due to possible 

effects of non-Lagrangian sampling, OWC results for the Volga 

area might indicate that (1) for the August 2003 sampling 

period, nonpoint livestock agricultural and/or human wastewater sources (other than the Volga WWTP) primarily contributed 

to occurrence of OWCs at Big Sioux River sampling sites; 

(2) for the October 2003 sampling period, nonpoint livestock 

sources and/or human wastewater sources (including the Volga 

WWTP) primarily contributed to occurrence of OWCs at Big 

Sioux River sampling sites; (3) for the June 2004 sampling 

period, nonpoint crop agricultural sources primarily contributed 

to occurrence of OWCs at Big Sioux River sampling sites; 

(4) for the August 2003 and June 2004 sampling periods, seepage of water from the Volga WWTP had little effect on downstream OWC concentrations; and (5) for the October 2003 

sampling period, the Volga wastewater effluent discharge 

contributed to downstream OWC concentrations.

HPCs were detected in samples from all sites in the Volga 

area (fig. 9, tables 6 and 7). Two HPCs (caffeine and cotinine) 

were detected in samples collected from all sites in the Volga 

area. In samples from VL-US1, total estimated HPC concentrations were less than 0.04 μg/L and accounted for less than 

3 percent of the total OWC concentration in any sample collected from VL-US1. In samples from VL-WWE, total estimated HPC concentrations were less than 0.1 μg/L, and 

accounted for about 3 percent of the total OWC concentration 

in any sample collected from VL-WWE. In samples collected 

from VL-DS1 and VL-DS2/BK-US1, total estimated HPC concentrations were less than 0.1 μg/L and accounted for less than 

about 3 percent of the total OWC concentration in any sample 

collected from VL-DS1 or VL-DS2/BK-US1. 
0.1

1

10

100

1,000

19 20 22 23 21 24 25

AUGUST 2003

DISCHARGE, IN CUBIC FEET PER SECOND

Station 06479770 streamflowStation 06480000 streamflowVL-US1 sample collectedVL-DS2/BK-US1 sample collectedVL-WWE sample collectedVL-DS1 sample collected

0.1

1

10

100

1,000

20 21 22 23

OCTOBER 2003

0.1

1

10

100

1,000

15 16 

JU

August 20-21, 2003 October 21-22, 2003 June 1

EXPLANATION

Volga wastewater treatment facility effluent dischargeto the Big Sioux River was 0 at the time of sampling

Volga wastewater treto the Big Sioux Rive

Volga wastewater treatment facility effluent dischargeestimated based on average discharge duringOctober 1-31, 2003

VL-WWE discharge

Figure 7. Flow conditions during sampling periods for sites in the Volga area.
0

20

406080

100120140

DISCHARGE,

IN CUBIC FEET PER SECOND

TURBIDITY,

IN NEPHELOMETRIC TURBIDITY UNITS

02

468

101216141820

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE V

DISSOLVED OXYGEN,

IN MILLIGRAMS PER LITER

August 20-21, 2003 October 21-22, 2003

SITE LABEL SITE LABEL

Turbiditydata notcollected

02

468

101216141820

June 16-17, 

SITE LAB

02

468

101216141820

05

101520253040354550

05

101520253040354550

05

101520253040354550

0

20

406080

100120140

0

20

406080

100120140

No data collected No data collected No data collected

Figure 8. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the Big Sioux Riv
0

5

101520253035

02

468

101214

02

468

101214

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE 

August 20-21, 2003 October 21-22, 2003

SITE LABEL SITE LABEL

June 16-1

SITE L

0

1,0002,0003,0004,0005,0006,0007,0008,000

0

1,0002,0003,0004,0005,0006,0007,0008,000

05

101520253035

05

101520253035

02

468

101214

No data collected No data collected

pH, IN STANDARD UNITS

SPECIFIC CONDUCTANCE,

IN MICROSIEMENS PER CENTIMETER

AT 25 DEGREES CELSIUS

WATER TEMPERATURE,

IN DEGREES CELSIUS

0

1,0002,0003,0004,0005,0006,0007,0008,000

No data collected

Figure 8. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the Big Sioux Rive

area.—Continued
0

5

1015202530

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE 

August 20-21, 2003 October 21-22, 2003

SITE LABEL SITE LABEL

June 16-17

SITE LA

0

0.1

0.20.30.40.50.60.70.90.81.0

NITRITE PLUS NITRATE NITROGEN,

IN MILLIGRAMS PER LITER

TOTAL COLIFORM BACTERIA,

IN COLONIES PER 100 MILLILITERS FECAL COLIFORM BACTERIA,

IN COLONIES PER 100 MILLILITERS

0

10,000

20,00030,00040,00050,00060,00070,00090,00080,000

100,000

0

1,000

2,0003,0004,0005,0006,0007,0009,0008,000

10,000

0

1,000

2,0003,0004,0005,0006,0007,0009,0008,000

10,000

0

0.1

0.20.30.40.50.60.70.90.81.0

0

0.1

0.20.30.40.50.60.70.90.81.0

Concentration less than laboratory

reporting level (0.06 mg/L)

Concentration less than laboratory

reporting level (0.06 mg/L)

Concentration less than laboratory

reporting level (0.06 mg/L)

Concentration less than laboratory

reporting level (0.06 mg/L)

Concentration less than laboratory

reporting level (0.06 mg/L)

Concentration less than laboratory

reporting level (0.06 mg/L)

No data collected No data collected

05

1015202530

05

1015202530

No data collected

Concentration less than laboratory

reporting level (10 colonies per

100 milliliters)

Figure 8. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the Big Sioux Rive

area.—Continued
0

0.51.01.5

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL

August 20-21, 2003 October 21-22, 2003

SITE LABEL SITE LABEL

June 16-17, 

SITE LABE

0

5

10152025

NUMBER OF COMPOUNDS DETECTED CONCENTRATION,

IN MICROGRAMS PER LITER LOAD, IN POUNDS PER DAY

05

101520253035

05

101520253035

05

101520253035

No data collected

0

5

10152025

0

5

10152025

No data collected

0

0.51.01.5

0

0.51.01.5

No data collected

Zero load due to zero discharge

Zero load due to zero discharge

EXPLANATION

Household, industrial, and minor agricultural use compounds (HIACs)

Major agricultural herbicides (MAHs)

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound class represents the amou compound class contributes to the total

Sterol compounds (SCs)

Human and veterinary antibiotic compounds (HVACs)

Human pharmaceutical c

Figure 9. Summary of results for organic wastewater compounds in wastewater effluent and the Big Sioux River in the Volga area.
Table 6. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux Rivin the Volga area.[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewa

wetland, near Volga, SD

(VL-DS1)

Date of sample collection 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004 08-21-2003 10-22-2003 06-16-2Time of sample collection 1400 1105 1145 0900 1240 1435 1100 0935 1615 

Human pharmaceutical compounds (HPCs)

Number of compounds detected 1 1 2 1 1 2 1 2 1 Minimum detected concentration (μg/L) e0.035 e0.022 e0.0070 e0.049 e0.019 e0.0089 e0.038 0.024 e0.003Median detected concentration (μg/L) e0.035 e0.022 e0.018 e0.049 e0.019 e0.042 e0.038 0.048 e0.003Maximum detected concentration (μg/L) e0.035 e0.022 0.030 e0.049 e0.019 0.075 e0.038 0.073 e0.003Total detected concentration (μg/L) e0.035 e0.022 e0.037 e0.049 e0.019 e0.084 e0.038 0.097 e0.003Total load (lb/d) e0.0027 e0.0011 e0.025 -- e0.0001 -- e0.0023 e0.0051 e0.002

Human and veterinary antibiotic compounds (HVACs)

Number of compounds detected 0 0 1 0 0 2 0 0 1 Minimum detected concentration (μg/L) 0 0 0.060 0 0 0.043 0 0 0.063 Median detected concentration (μg/L) 0 0 0.060 0 0 0.057 0 0 0.063 Maximum detected concentration (μg/L) 0 0 0.060 0 0 0.071 0 0 0.063 Total detected concentration (μg/L) 0 0 0.060 0 0 0.11 0 0 0.063 Total load (lb/dd) 0 0 e0.041 -- 0 -- 0 0 e0.044 

Major agricultural herbicides (MAHs)

Number of compounds detected 1 2 2 1 1 1 1 2 3 Minimum detected concentration (μg/L) e0.093 e0.050 e0.035 e0.055 e0.059 e0.18 e0.076 e0.050 e0.055 Median detected concentration (μg/L) e0.093 e0.053 e0.49 e0.055 e0.059 e0.18 e0.076 e0.056 e0.069 Maximum detected concentration (μg/L) e0.093 e0.055 0.95 e0.055 e0.059 e0.18 e0.076 e0.061 1.5 Total detected concentration (μg/L) e0.093 e0.10 e0.99 e0.055 e0.059 e0.18 e0.076 e0.11 e1.6 
Total load (lb/d) e0.0072 e0.0051 e0.67 -- e0.0002 -- e0.0047 e0.0058 e1.1 

Household, industrial, and minor agricultural use compounds (HIACs)

Number of compounds detected 4 7 0 4 11 2 1 7 1 Minimum detected concentration (μg/L) e0.043 e0.024 0 e0.029 e0.016 e0.085 e0.060 e0.083 e0.19 Median detected concentration (μg/L) e0.068 e0.15 0 e0.058 e0.13 e0.098 e0.060 e0.16 e0.19 Maximum detected concentration (μg/L) e0.29 e3.3 0 e0.23 e5.1 e0.11 e0.060 e3.4 e0.19 Total detected concentration (μg/L) e0.47 e5.6 0 e0.38 e9.2 e0.20 e0.060 e6.3 e0.19 Total load (lb/d) e0.036 e0.27 0 -- e0.030 -- e0.0037 e0.33 e0.13 

Polyaromatic hydrocarbons (PAHs)

Number of compounds detected 0 0 0 0 0 0 0 0 0 Minimum detected concentration (μg/L) 0 0 0 0 0 0 0 0 0 Median detected concentration (μg/L) 0 0 0 0 0 0 0 0 0 Maximum detected concentration (μg/L) 0 0 0 0 0 0 0 0 0 Total detected concentration (μg/L) 0 0 0 0 0 0 0 0 0 Total load (lb/d) 0 0 0 0 0 -- 0 0 0 

Sterol compounds (SCs)

Number of compounds detected 2 3 0 1 3 1 2 3 0 Minimum detected concentration (μg/L) e1.6 e0.54 0 e1.4 e0.78 2.1 e1.4 e0.73 0 Median detected concentration (μg/L) e2.6 e1.1 0 e1.4 2.0 2.1 e1.6 2.3 0 Maximum detected concentration (μg/L) 3.6 e1.3 0 e1.4 2.8 2.1 e1.9 2.4 0 Total detected concentration (μg/L) e5.2 e2.9 0 e1.4 e5.6 2.1 e3.3 e5.4 0 Total load (lb/d) e0.40 e0.14 0 -- e0.018 -- e0.20 e0.28 0 

Table 6. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux Riv

in the Volga area.—Continued

[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewa

wetland, near Volga, SD

(VL-DS1)
All organic wastewater compounds (OWCs)

Number of compounds detected 8 13 5 7 16 8 5 14 6 Minimum detected concentration (μg/L) e0.035 e0.022 e0.0070 e0.029 e0.016 e0.0089 e0.038 0.024 e0.003Median detected concentration (μg/L) e0.081 e0.15 e0.035 e0.055 e0.16 e0.080 e0.076 e0.14 e0.066 Maximum detected concentration (μg/L) 3.6 e3.3 0.95 e1.4 e5.1 2.1 e1.9 e3.4 1.5 Total detected concentration (μg/L) e5.8 e8.7 e1.1 e1.9 e15 e2.7 e3.5 e12 e1.9 Total load (lb/d) e0.45 e0.42 e0.74 -- e0.048 -- e0.21 e0.62 e1.3 

Endocrine-disrupting compounds (EDCs) from all compound classes

Number of compounds detected 1 4 1 2 5 1 0 4 1 Minimum detected concentration (μg/L) e0.069 e0.050 0.95 e0.029 e0.059 e0.18 0 e0.050 1.5 Median detected concentration (μg/L) e0.069 e0.93 0.95 e0.042 e0.26 e0.18 0 e1.18 1.5 Maximum detected concentration (μg/L) e0.069 e3.3 0.95 e0.055 e5.1 e0.18 0 e3.4 1.5 Total detected concentration (μg/L) e0.069 e5.2 0.95 e0.084 e8.4 e0.18 0 e5.8 1.5 Total load (lb/d) e0.0054 e0.25 e0.65 -- e0.027 -- 0 e0.30 e1.1 

Table 6. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux Riv

in the Volga area.—Continued

[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewa

wetland, near Volga, SD

(VL-DS1)
Table 7. Detected organic wastewater compounds in wastewater effluent and the Big Sioux River in the Volga area.

[Bold text for compound names indicates suspected endocrine-disrupting compounds (EDCs). NP2EO, nonylphenol diethoxylate; NP1EO, nonylphenol monoethoxylate; OP2EODEET, N,N-diethyl-meta-toluamide; --, not detected]

Station identification number and name (site label)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

Date of sample collection 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004 08-21-2003 10-22-2003 06-16-2004 Time of sample collection 1400 1105 1145 0900 1240 1435 1100 0935 1615 Number of compounds detected 8 13 5 7 16 8 5 14 6 Human pharmaceutical compounds 

(HPCs)

Cotinine Cotinine Caffeine

Cotinine

Cotinine Cotinine Caffeine

Cotinine

Cotinine Caffeine

Cotinine

Cotinine 

Human and veterinary antibiotic 

compounds (HVACs)

-- -- Erythromycin-H2O -- -- Erythromycin Erythromycin

-H2O

-- -- Erythromyci

-H2O

Major agricultural herbicides 

(MAHs)

Prometon Atrazine

Prometon

AtrazineMetolachlor

Atrazine Atrazine Atrazine Prometon Atrazine

Prometon

AtrazineMetolachlorPrometon

Household, industrial, and minor 

agricultural use compounds (HIACs)

Bisphenol-AIndoleTri(2-

butoxyethyl)phosphate

Tri(2-

chloroethyl)phosphate

AcetophenoneIndoleNP2EONP1EOOP2EOTributyl 

phosphate

Tri(2-

chloroethyl)phosphate

-- Benzophenone

DEETIsophoroneTri(2-

chloroethyl)phosphate

5-methyl-1HbenzotriazoleAcetophenoneBisphenol-ACamphorIndoleIsophoroneNP2EONP1EOOP2EOpara-cresolTri(2-

chloroethyl)phosphate

DEETTri(2-

chloroethyl)phosphate

Tri(2-

chloroethyl)phosphate

AcetophenoneIndoleNP2EONP1EOOP2EOTributyl 

phosphate

Tri(2-

chloroethyl)phosphate

Tri(2-

butoxyethyphosphate

PAH compounds (PAHs) -- -- -- -- -- -- -- -- -- Sterol compounds (SCs) beta-sitosterol

Cholesterol

3-betacoprostanolbeta-sitosterolCholesterol

-- Cholesterol 3-betacoprostanol

beta-sitosterolCholesterol

Cholesterol beta-sitosterol

Cholesterol

3-betacoprostanolbeta-sitosterolCholesterol

-- 
Occurrence of Organic Wastewater Compounds 37

HVACs were detected in June 2004 samples collected 

from all sampling sites in the Volga area (fig. 9, tables 6 and 7). 

No HVACs were detected in any August 2003 sample from 

sites in the Volga area. One HVAC (erythromycin-H2O) was 

detected in the June 2004 VL-US1 sample at an estimated concentration of 0.06 μg/L and accounted for about 6 percent of the 

total OWC concentration. Two HVACs (erythromycin and 

erythromycin-H2O) were detected in the June 2004 VL-WWE 

sample with a total estimated concentration of 0.11 μg/L, which 

accounted for about 4 percent of the total OWC concentration. 

One HVAC (erythromycin-H2O) was detected in the June 2004 

samples from the downstream sites VL-DS1 and VL-DS2/BKDS1 at estimated concentrations less than 0.063 μg/L, which 

accounted for about 3 percent of the total OWC concentrations 

at both sites. The detections of HVACs in the June 2004 

samples and the non-detections in the August 2003 and October 

2003 samples might be related to changes in the analytical 

method that substantially reduced the LRLs for HVACs. 

MAHs were detected in samples collected from all sampling sites in the Volga area (fig. 9, tables 6 and 7). Three 

MAHs (atrazine, metolachlor, and prometon) were detected in 

samples collected from the upstream site VL-US1 with total 

estimated concentrations of 0.093, 0.10, and 0.99 μg/L, which 

accounted for about 2, 1, and 91 percent of the total OWC concentrations for the August 2003, October 2003 samples, and 

June 2004 samples, respectively. Atrazine was the only MAH 

detected in samples collected from VL-WWE with concentrations less than 0.2 μg/L, which accounted for less than about 

7 percent of the total OWC concentration for any VL-WWE 

sample. Three MAHs (atrazine, metolachlor, and prometon) 

were detected in samples collected from the downstream sites 

VL-DS1 and VL-DS2/BK-US1. Total estimated MAH concentrations ranged from 0.08 to 1.6 μg/L, which accounted for less 

than about 4 percent of the total OWC concentrations for the 

August 2003 and October 2003 samples, and about 84 and 

86 percent for the June 2004 VL-DS1 and VL-DS2/BK-US1 

samples, respectively. MAH concentrations at all sampling sites 

in the Volga area were larger in June 2004 samples than in 

August 2003 or October 2003 samples.

HIACs were detected in samples collected from all sites in 

the Volga area (fig. 9, tables 6 and 7). Eight HIACs were 

detected in August 2003 and October 2003 samples collected 

from upstream site VL-US1 with total estimated concentrations 

ranging from 0.47 to 5.6 μg/L. No HIACs were detected in the 

June 2004 VL-US1 sample. For VL-US1 samples, HIACs with 

the largest estimated concentrations were NP2EO and NP1EO 

(3.3 and 1.7 μg/L, respectively, for the October 2003 sample), 

and all other individual HIACs had detected concentrations less 

than 0.3 μg/L. Total HIAC concentrations accounted for about 

8 and 64 percent of the total OWC concentrations for the 

August 2003 and October 2003 VL-US1 samples, respectively. 

Thirteen HIACs were detected in samples from VL-WWE with 

total estimated HIAC concentrations ranging from 0.20 to 

9.2 μg/L. For VL-WWE samples, HIACs with the largest 

estimated concentrations were NP2EO and NP1EO (5.1 and 

2.9 μg/L, respectively, for the October 2003 sample), and 

detected concentrations of all other individual HIACs were less 

than 0.4 μg/L. Total HIAC concentrations accounted for about 

20, 61, and 7 percent of the total OWC concentration for the 

August 2003, October 2003, and June 2004 VL-WWE samples, 

respectively. Eight HIACs were detected in samples from 

VL-DS1, with total estimated concentrations ranging from 

0.060 to 6.3 μg/L. HIACs with the largest estimated concentrations in samples from VL-DS1 were NP2EO and NP1EO (3.4 

and 2.2 μg/L, respectively, for the October 2003 sample), and 

all other individual HIACs had detected concentrations less 

than 0.2 μg/L. Total estimated HIAC concentrations accounted 

for 2, 52, and 10 percent of the total OWC concentrations for 

the August 2003, October 2003, and June 2004 VL-DS1 samples, respectively. Three HIACs—N,N-diethyl-meta-toluamide 

(DEET), tri(2-butoxyethyl)phosphate, and tri(2-chloroethyl)

phosphate)—were detected in samples from VL-DS2/BK-US1 

with total HIAC concentrations of 0.25 μg/L or less, which 

accounted for about 10 and 6 percent of the total OWC concentrations for the August 2003 and June 2004 samples, respectively. 

SCs were detected in samples collected from all sites in the 

Volga area (fig. 9, tables 6 and 7). Three SCs (3-beta coprostanol, beta-sitosterol, and cholesterol) were detected in August 

2003 and October 2003 samples collected from VL-US1 with 

total estimated SC concentrations ranging from 2.9 to 5.2 μg/L. 

No SCs were detected in the June 2004 sample from VL-US1. 

Total SC concentrations accounted for about 90 and 33 percent 

of the total OWC concentration for the August 2003 and 

October 2003 VL-US1 samples, respectively. The same three 

SCs (3-beta coprostanol, beta-sitosterol, and cholesterol) were 

detected in samples collected from VL-WWE with total estimated SC concentrations ranging from 1.4 to 5.6 μg/L. Total SC 

concentrations accounted for about 74, 37, and 78 percent of the 

total OWC concentration for the August 2003, October 2003, 

and June 2004 VL-WWE samples, respectively. The same three 

SCs were detected in the August 2003 and October 2003 VLDS1 samples with total estimated concentrations ranging from 

3.3 to 5.4 μg/L. No SCs were detected in the June 2004 VL-DS1 

sample. Total SC concentrations accounted for about 94 and 

45 percent of the total OWC concentration for the August 2003 

and October 2003 VL-DS1 samples, respectively. Two SCs 

(beta-sitosterol and cholesterol) were detected in the August 

2003 VL-DS2/BK-US1 sample with a combined estimated concentration of 2.0 μg/L, which accounted for about 83 percent of 

the total OWC concentration. No SCs were detected in the June 

2004 VL-DS1/BK-US1 sample.

EDCs were detected at all sampling sites in the Volga area 

(fig. 10, tables 6 and 7). Five different EDCs were detected in 

samples collected from VL-US1 (atrazine, an MAH; and 

bisphenol-A, NP2EO, NP1EO, and octylphenol diethoxylate 

(OP2EO), which are HIACs) with total estimated EDC concentrations ranging from 0.069 to 5.2 μg/L. Of the total EDC concentrations, HIACs accounted for 100, 99, and 0 percent, and 

MAHs accounted for 0, 1, and 100 percent for the August 2003, 

October 2003, and June 2004 VL-US1 samples, respectively. 

Six EDCs were detected in samples collected from VL-WWE 
0

0.51.01.5

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL-DS1 VL-DS2/

BK-US1

VL-US1 VL-WWE VL

August 20-21, 2003 October 21-22, 2003

SITE LABEL SITE LABEL

June 16-17, 

SITE LABE

01

2345678

0

0.51.01.5

0

0.51.01.5

No data collected

No data collected

No data collected

NUMBER OF COMPOUNDS

DETECTED

CONCENTRATION,

IN MICROGRAMS PER LITER LOAD, IN POUNDS PER DAY

01

2345678

01

2345678

No data collected

0

12345678

10

9

0

12345678

10

9

0

12345678

10

9

No data collected

EXPLANATION

Major agricultural herbicides (MAHs)—Suspected for being endocrine disrupting compounds

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound class represe amount that compound class contributes to the total

Suspected endocrine disrupting compounds—From all compound classes (excluding major agricultural herbi

Figure 10. Summary of results for endocrine-disrupting compounds (EDCs) from all compound classes in wastewater effluent and the Big Sioux R
Occurrence of Organic Wastewater Compounds 39

(atrazine, which is an MAH; and benzophenone, bisphenol-A, 

NP2EO, NP1EO, and OP2EO, which are HIACs) with total 

estimated EDC concentrations ranging from 0.084 to 8.4 μg/L. 

Of the total EDC concentrations, HIACs accounted for about 

35, 99, and 0 percent, and MAHs accounted for about 65, 1, and 

100 percent for the August 2003, October 2003, and June 2004 

VL-WWE samples, respectively. Four EDCs were detected in 

samples collected from VL-DS1 (atrazine, an MAH; and 

NP2EO, NP1EO, and OP2EO, which are HIACs) with total 

estimated EDC concentrations ranging from undetected to 

5.8 μg/L. HIACs accounted for nearly all of the total EDC concentration at VL-DS1 for the October 2003 sample, and MAHs 

accounted for all of the total EDC concentration for the June 

2004 sample. One EDC was detected in the June 2004 sample 

collected from VL-DS2/BK-US1 (atrazine, an MAH) at an 

estimated concentration of 1.2 μg/L.

Brookings Area Results

Sites in the Brookings area were sampled during 

August 21–22, 2003, when generally low-flow conditions prevailed and during June 17–18, 2004, when runoff conditions 

prevailed. Flow conditions during sampling periods are shown 

in figure 11. During August 20–22, 2003, streamflow at longterm USGS gaging station 06480000, located about 4.7 river 

miles downstream from sampling site BK-DS2, was about 

32 percent of the long-term (1953–2004) median mid-August 

flow. During June 16–18, 2004, streamflow at station 06480000 

was about 148 percent of the long-term median mid-June flow. 

The Brookings WWTP discharged continuously to the Big 

Sioux River during both sampling periods. During the August 

2003 sampling period, the Brookings WWTP discharge 

accounted for about 10 to 40 percent of the flow of the Big 

Sioux River from the confluence of the WWTP discharge to 

several miles downstream. During the June 2004 sampling 

period, the Brookings WWTP discharge accounted for about 

1 to 2 percent of the flow of the Big Sioux River from the confluence of the WWTP discharge to several miles downstream. 

Field-Measured Properties and Constituents

Results for field-measured properties and constituents and 

auxiliary constituents in samples from sites in the Brookings 

area are presented in figure 12 and table 17. Generally, results 

for field-measured properties and constituents and auxiliary 

constituents for the Brookings area were within typical ranges 

for the upper Big Sioux River Basin (East Dakota Water 

Development District, 2004).

0.1

1

10

100

1,000

15 16 17 18 19

AUGUST 2003

DISCHARGE, IN CUBIC FEET PER SECOND

JUNE 2004

August 21-22, 2003 June 17-18, 2004

0.1

1

10

100

1,000

20 21 22 23

Station 06480000 discharge

Station 06479770 discharge

BK-DS2 sample collected

VL-DS2/BK-US1 sample collected

BK-WWE sample collected

BK-DS1 sample collected

EXPLANATION

BK-WWE discharge

Figure 11. Flow conditions during sampling periods for sites in the Brookings area.
0

50

100

150

200

250

300

0

50

100

150

200

250

300

DISCHARGE, IN CUBIC FEET PER SECOND

0

5

10

15

20

25

30

35

40

TURBIDITY, IN NEPHELOMETRIC TURBIDITY UNITS

0

5

10

15

20

25

30

35

40

0

2

4

6

8

10

12

16

14

18

20

VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1 VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1

DISSOLVED OXYGEN, IN MILLIGRAMS PER LITER

August 21-22, 2003 June 17-18, 2004

SITE LABEL SITE LABEL

Turbidity

data not

collected

0

2

4

6

8

10

12

16

14

18

20

40 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 12. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the 

Big Sioux River in the Brookings area.
0

2

4

6

8

10

12

14

pH, IN STANDARD UNITS SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER

AT 25 DEGREES CELSIUS

0

5

10

15

20

25

30

WATER TEMPERATURE, IN DEGREES CELSIUS

August 21-22, 2003 June 17-18, 2004

SITE LABEL SITE LABEL

0

2

4

6

8

10

12

14

0

200

400

600

800

1,000

1,200

1,800

1,400

1,600

0

5

10

15

20

25

30

VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1 VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1

0

200

400

600

800

1,000

1,200

1,800

1,400

1,600

Occurrence of Organic Wastewater Compounds 41

Figure 12. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the 

Big Sioux River in the Brookings area.—Continued
0

5

10

15

25

20

NITRITE PLUS NITRATE NITROGEN,

IN MILLIGRAMS PER LITER

TOTAL COLIFORM BACTERIA,

IN COLONIES PER 100 MILLILITERS

FECAL COLIFORM BACTERIA,

IN COLONIES OF 100 MILLILITERS

SITE LABEL SITE LABEL

0

500

1,000

1,500

2,000

2,500

0

100

200

300

400

500

600

August 21-22, 2003 June 17-18, 2004

VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1 VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1

0

5

10

15

25

20

Concentration less than laboratory reportinglevel (0.06 milligrams per liter)

Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)

0

500

1,000

1,500

2,000

2,500

Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)

0

100

200

300

400

500

600

Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)Concentration less than laboratory reportinglevel (10 colonies per 100 milliliters)

42 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Figure 12. Results for selected field-measured properties and constituents and auxiliary constituents in wastewater effluent and the 

Big Sioux River in the Brookings area.—Continued
Occurrence of Organic Wastewater Compounds 43

Organic Wastewater Constituents

OWCs in all compound classes except PAHs were 

detected in water samples from sampling sites in the Brookings 

area (fig. 13, tables 8 and 9). Differences in total OWC concentrations and loads between the upstream Big Sioux River site 

(VL-DS2/BK-US1) and downstream sites (BK-DS1 and 

BK-DS2) were variable. For August 2003, the upstream site had 

a slightly smaller total OWC concentration and load compared 

to the downstream sites. SCs and HIACs accounted for about 

85 and 10 percent, respectively, for both VL-DS2/BK-US1 

and BK-DS1 total OWC concentrations, and about 76 and 

20 percent of the BK-DS2 total OWC concentration. Loads of 

total OWCs generally were similar for the August 2003 BKWWE, BK-DS1, and BK-DS2 samples, but HIACs accounted 

for more of the total OWC load for BK-WWE than for BK-DS1 

and BK-DS2. This might be due to (1) contribution of SCs in 

water entering the Big Sioux River channel downstream from 

the Brookings WWTP effluent discharge; (2) degradation of 

HIACs in the Big Sioux River; (3) adsorption of HIACs to 

particulate material and sedimentation from the water column; 

(4) diurnal variability in wastewater effluent discharges and relative concentrations of SCs and HIACs in the wastewater effluent combined with effects of non-Lagrangian sampling; and 

(5) dilution of HIAC concentrations that can directly reduce 

concentrations and can possibly reduce load estimates by 

decreasing concentrations to less than detectable levels. For 

June 2004, VL-DS2/BK-US1 generally had a smaller total 

OWC concentration and load than the downstream sites. MAHs 

accounted for about 86, 91, and 54 percent of the June 2004 

total OWC concentrations for VL-DS2/BK-US1, BK-DS1, and 

BK-DS2, respectively. SCs accounted for about 40 percent of 

the June 2004 total OWC concentration for BK-DS2. Although 

confident conclusions cannot be made due to possible effects of 

non-Lagrangian sampling, OWC results for the Brookings area 

might indicate that (1) for the August 2003 sampling period, 

nonpoint livestock agricultural and/or human wastewater 

sources probably primarily contributed to occurrence of OWCs 

at all Big Sioux River sampling sites, and the Brookings WWTP 

wastewater effluent discharge contributed but did not have a 

substantial effect on concentrations at downstream sites; (2) for 

the June 2004 sampling period, nonpoint crop agricultural 

sources primarily contributed to occurrence of OWCs at all of 

the Big Sioux River sites, a substantial amount of SCs were contributed to the Big Sioux River downstream between BK-DS1 

and BK-DS2, and the Brookings WWTP wastewater effluent 

discharge probably did not substantially contribute to total 

OWC concentrations at downstream sampling sites.

HPCs were detected in samples from all sites in the Brookings area (fig. 13, tables 8 and 9). Two HPCs (caffeine and 

cotinine) were detected in the August 2003 VL-DS2/BK-US1 

sample with a total estimated concentration less than 0.1 μg/L, 

which accounted for less than about 3 percent of the total OWC 

concentration. No HPCs were detected in the June 2004 

VL-DS2/BK-US1 sample. Two HPCs (cotinine and dehydronifedipine) were detected in samples collected from BK-WWE 

with total estimated concentrations less than 0.03 μg/L, which 

accounted for less than about 0.3 percent of the total OWC concentration. Two HPCs (caffeine and cotinine) were detected in 

samples collected from downstream sites BK-DS1 and BK-DS2 

with total estimated concentrations less than 0.1 μg/L, which 

accounted for no more than about 5 percent of the total OWC 

concentrations. 

HVACs were detected in all June 2004 samples collected 

from sampling sites in the Brookings area (fig. 13, tables 8 

and 9). No HVACs were detected in any August 2003 samples. 

The increase in HVAC detections and total HVAC concentrations for the June 2004 samples relative to the August 2003 

samples for all of the sampling sites in the Brookings area might 

be related to changes in the analytical method that substantially 

reduced the LRLs for HVACs. One HVAC (erythromycinH2O) was detected in the June 2004 VL-DS2/BK-US1 sample 

at an estimated concentration of 0.048 μg/L, and accounted for 

about 3 percent of the total OWC concentration. Eight HVACs 

were detected in the June 2004 BK-WWE sample with a total 

estimated concentration of 3.6 μg/L, which accounted for about 

28 percent of the total OWC concentration. Erythromycin, 

erythromycin-H2O, and sulfamethoxazole had the largest estimated concentrations (0.71, 2.0, and 0.50 μg/L, respectively) in 

the BK-WWE sample. Two HVACs (erythromycin-H2O and 

sulfamethoxazole) were detected in the June 2004 samples collected from downstream sites BK-DS1 and BK-DS2 with total 

estimated concentrations less than 0.1 μg/L, which accounted 

for about 6 and 3 percent of the total OWC concentrations for 

the June 2004 BK-DS1 and BK-DS2 samples, respectively. 

MAHs were detected in samples collected from all sampling sites in the Brookings area (fig. 13, tables 8 and 9). Three 

MAHs (atrazine, metolachlor, and prometon) were detected in 

samples collected from VL-DS2/BK-US1 with total estimated 

concentrations ranging from 0.10 to 1.2 μg/L, which accounted 

for about 4 and 86 percent of the total OWC concentrations for 

the August 2003 and June 2004 samples, respectively. Two 

MAHs (atrazine and prometon) were detected in samples collected from BK-WWE with total estimated concentrations less 

than 0.1 μg/L, which accounted for less than 1 percent of the 

total OWC concentrations. Three MAHs (atrazine, metolachlor, 

and prometon) were detected in samples collected from BKDS1 and BK-DS2 with total estimated concentrations ranging 

from 0.081 to 1.3 μg/L. These total MAH concentrations 

accounted for about 3 percent of the total OWC concentrations 

for the August 2003 samples and about 91 and 54 percent of the 

total OWC concentration for the June 2004 BK-DS1 and 

BK-DS2 samples, respectively.

HIACs were detected in samples from all sites in the 

Brookings area (fig. 13, tables 8 and 9). Three HIACs—DEET, 

tri(2-butoxyethyl)phosphate, and tri(2-chloroethyl)phosphate—were detected in samples from VL-DS2/BK-US1 with 

total estimated concentrations of less than 0.25 μg/L, which 

accounted for about 10 and 6 percent of the total OWC 

concentrations for the August 2003 and June 2004 samples, 
44 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

respectively. Sixteen HIACs were detected in samples from 

BK-WWE with total estimated concentrations ranging from 5.4 

to 7.2 μg/L, which accounted for about 60 percent of the total 

OWC concentrations for both the August 2003 and June 2004 

samples. AHTN had concentrations of 2.0 and 2.3 μg/L for the 

August 2003 and June 2004 BK-WWE samples, respectively, 

and NP2EO had a concentration of 1.2 μg/L for the June 2004 

sample. All other individual HIACs had estimated concentrations less than 0.8 μg/L for all BK-WWE samples. Seven 

HIACs were detected in the August 2003 BK-DS1 and BK-DS2 

samples with total estimated concentrations ranging from 0.33 

to 0.67 μg/L, which accounted for about 11 and 20 percent of 

the total OWC concentrations for the August 2003 samples, 

respectively. Concentrations of individual HIACs for the 

August 2003 BK-DS1 and BK-DS2 samples were all less than 

about 0.25 μg/L. No HIACs were detected in the June 2004 

BK-DS1 or BK-DS2 samples. 

SCs were detected in samples from all sites in the Brookings area (fig. 13, tables 8 and 9). Two SCs (beta-sitosterol and 

cholesterol) were detected in the August 2003 VL-DS2/BKUS1 sample with a total estimated concentration of 2.0 μg/L, 

which accounted for about 83 percent of the total OWC concentration. No SCs were detected in the June 2004 VL-DS1/BKUS1 sample. Three SCs (3-beta-coprostanol, beta-sitosterol, 

and cholesterol) were detected in samples from BK-WWE 

samples with total estimated concentrations ranging from 1.8 to 

3.6 μg/L, which accounted for about 40 and 14 percent of the 

total OWC concentration for the August 2003 and June 2004 

samples, respectively. Two SCs (beta-sitosterol and cholesterol) were detected in August 2003 samples collected from the 

downstream sites BK-DS1 and BK-DS2 with total estimated 

concentrations ranging from 2.5 to 2.7 μg/L, which accounted 

for about 87 and 76 percent of the total OWC concentration for 

the August 2003 BK-DS1 and BK-DS2 samples, respectively. 

No SCs were detected in the June 2004 BK-DS1 sample and the 

June 2004 BK-DS2 sample had one SC detection (cholesterol) 

at an estimated concentration of 0.96 μg/L, which accounted for 

about 40 percent of the total OWC concentration. 

EDCs were detected in all samples collected from sampling sites in the Brookings area except the August 2003 sample 

from VL-DS2/BK-US1 (fig. 14, tables 8 and 9). For August 

2003, the numbers of EDCs detected, and EDC concentrations 

and loads generally were larger for BK-WWE than for downstream sampling sites BK-DS1 and BK-DS2. For June 2004, 

EDC concentrations were similar among Big Sioux River sites, 

and loads were larger for downstream Big Sioux River sites 

than for the upstream site, but the EDCs detected for June 2004 

Big Sioux River samples consist entirely of MAHs and probably were contributed primarily by nonpoint sources. One EDC 

was detected in samples collected from VL-DS2/BK-US1 

(atrazine, an MAH) with an estimated concentration of 

1.2 μg/L. Nine EDCs were detected in samples collected from 

BK-WWE (atrazine, an MAH; and AHTN, benzophenone, 

bisphenol-A, HHCB, NP2EO, NP1EO, NP, and triclosan, 

which are HIACs) with total estimated concentrations ranging 

from 3.0 to 5.4 μg/L. HIACs accounted for greater than about 

98 percent of the total EDC concentrations for both the August 

2003 and June 2004 BK-WWE samples. Four EDCs (atrazine, 

an MAH; and AHTN, benzophenone, and HHCB, which are 

HIACs) were detected in samples collected from BK-DS1 and 

BK-DS2 with total estimated concentrations ranging from 0.15 

to 1.3 μg/L. HIACs accounted for about 100 percent of the total 

EDC concentration for the August 2003 BK-DS1 sample, and 

MAHs accounted for about 100 percent of the total EDC concentration for the June 2004 BK-DS1 sample. HIACs accounted 

for about 100 percent of the total EDC concentration for the 

August 2003 BK-DS2 sample, and MAHs accounted for about 

100 percent of the total EDC concentration for the June 2004 

BK-DS2 sample.

Synopsis of Results

Several previous studies have reported concentrations of 

OWCs in natural waters and WWTP effluents in the United 

States. Kolpin and others (2002) reported OWCs in water samples collected from a network of 139 streams across 30 States 

during 1999–2000. Glassmeyer and others (2005) reported 

OWCs in water samples collected from WWTP effluents and 

natural receiving waters for 10 municipalities across the United 

States. Lee and others (2004) reported OWCs in water samples 

collected from 65 sites (wastewater, surface water, ground 

water, and drinking water) in Minnesota. Kolpin and others 

(2004) reported OWC concentrations in water samples collected from stream sites both upstream and downstream from 

WWTP effluent discharges of 10 cities in Iowa.

Detected concentrations of individual OWCs found in 

water samples collected from the upper Big Sioux River generally were within ranges of concentrations reported in these 

previous studies. Maximum concentrations of detected OWCs 

found in water samples collected from the upper Big Sioux 

River generally were substantially less than maxima reported 

by Kolpin and others (2002), Lee and others (2004), and Glassmeyer and others (2005), and generally were similar to maxima 

reported by Kolpin and others (2004). It should be noted that the 

maximum concentrations reported by Lee and others (2004) 

and Glassmeyer and others (2005) included results for WWTP 

effluents. A notable exception to these patterns is that some 

HVACs (including ciprofloxacin, erythromycin-H2O, sulfamethoxazole, and trimethoprim) were detected in water samples collected from the Big Sioux River downstream from 

Watertown at concentrations about 2 to 8 times larger than the 

median concentrations reported by Kolpin and others (2004) 

and approaching or exceeding maxima reported by Kolpin and 

others (2004), Lee and others (2004), and Glassmeyer and 

others (2005), even when concentrations in WWTP effluents 

were included.
NUMBER OF COMPOUNDS DETECTED

0

5

10

15

20

CONCENTRATION, IN MICROGRAMS PER LITER

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

LOAD, IN POUNDS PER DAY

August 21-22, 2003 June 17-18, 2004

0

5

10

15

20

25

30

35

0

5

10

15

20

25

30

35

SITE LABEL SITE LABEL

VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1 VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1

0

5

10

15

20

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

EXPLANATION

Sterol compounds (SHCs)

Household, industrial, and minor agricultural

 use compounds (HIACs)

Major agricultural herbicides (MAHs)

Human and veterinary antibiotic compounds (HVACs)

Human pharmaceutical compounds (HPCs)

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound

 class represents the amount that compound class contributes to the total

Synopsis of Results 45

Figure 13. Summary of results for organic wastewater compounds in wastewater effluent and the Big Sioux River in the Brookings 

area.
Table 8. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux RivBrookings area.[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent,

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent,

near Brookings, SD

(BK-DS1)

Big 

Date of sample collection 08-21-2003 06-17-2004 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08Time of sample collection 1230 1140 0915 0950 1015 1215 

Human pharmaceutical compounds (HPCs)

Number of compounds detected 2 0 2 1 1 2 Minimum detected concentration (μg/L) e0.029 0 e0.0052 0.022 0.030 e0.0023 Median detected concentration (μg/L) e0.031 0 e0.013 0.022 0.030 e0.025 Maximum detected concentration (μg/L) e0.033 0 e0.021 0.022 0.030 0.048 Total detected concentration (μg/L) e0.062 0 e0.026 0.022 0.030 e0.050 Total load (lb/d) e0.0011 0 e0.0002 e0.0007 e0.0016 e0.077 

Human and veterinary antibiotic compounds (HVACs)

Number of compounds detected 0 1 0 8 0 1 Minimum detected concentration (μg/L) 0 0.048 0 0.0090 0 0.065 Median detected concentration (μg/L) 0 0.048 0 0.12 0 0.065 Maximum detected concentration (μg/L) 0 0.048 0 2.0 0 0.065 Total detected concentration (μg/L) 0 0.048 0 3.6 0 0.065 Total load (lb/d) 0 e0.033 0 e0.11 0 e0.10 

Major agricultural herbicides (MAHs)

Number of compounds detected 1 2 1 1 1 3 Minimum detected concentration (μg/L) e0.10 e0.035 e0.050 e0.086 e0.081 e0.030 Median detected concentration (μg/L) e0.10 e0.62 e0.050 e0.086 e0.081 e0.044 Maximum detected concentration (μg/L) e0.10 1.2 e0.050 e0.086 e0.081 0.84 Total detected concentration (μg/L) e0.10 e1.2 e0.050 e0.086 e0.081 e0.91 Total load (lb/d) e0.0016 e0.86 e0.0005 e0.0026 e0.0043 e1.4 
Household, industrial, and minor agricultural use compounds (HIACs)

Number of compounds detected 2 1 13 10 6 0 Minimum detected concentration (μg/L) e0.056 e0.077 e0.017 e0.13 e0.032 0 Median detected concentration (μg/L) e0.12 e0.077 e0.27 e0.54 e0.054 0 Maximum detected concentration (μg/L) e0.19 e0.077 e2.0 2.3 e0.078 0 Total detected concentration (μg/L) e0.25 e0.077 e5.4 e7.2 e0.33 0 Total load (lb/d) e0.0042 e0.054 e0.049 e0.22 e0.018 0 

Polyaromatic hydrocarbons (PAHs)

Number of compounds detected 0 0 0 0 0 0 Minimum detected concentration (μg/L) 0 0 0 0 0 0 Median detected concentration (μg/L) 0 0 0 0 0 0 Maximum detected concentration (μg/L) 0 0 0 0 0 0 Total detected concentration (μg/L) 0 0 0 0 0 0 Total load (lb/d) 0 0 0 0 0 0 

Sterol compounds (SCs)

Number of compounds detected 2 0 3 1 2 0 Minimum detected concentration (μg/L) e1.0 0 e0.89 e1.8 e1.2 0 Median detected concentration (μg/L) e1.0 0 e1.1 e1.8 e1.4 0 Maximum detected concentration (μg/L) e1.0 0 e1.6 e1.8 e1.5 0 Total detected concentration (μg/L) e2.0 0 e3.6 e1.8 e2.7 0 Total load (lb/d) e0.034 0 e0.033 e0.054 e0.14 0 

Table 8. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux Riv

Brookings area.—Continued

[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent,

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent,

near Brookings, SD

(BK-DS1)

Big 
All organic wastewater compounds (OWCs)

Number of compounds detected 7 4 19 21 10 6 Minimum detected concentration (μg/L) 0.029 e0.035 e0.0052 e0.0090 e0.030 e0.0023 Median detected concentration (μg/L) e0.095 e0.062 e0.27 e0.36 e0.067 e0.046 Maximum detected concentration (μg/L) e1.0 1.2 e2.0 e2.3 e1.5 0.84 Total detected concentration (μg/L) e2.4 e1.4 e9.0 e13 e3.1 e1.0 Total load (lb/d) e0.041 e0.95 e0.083 e0.38 e0.17 e1.6 

Endocrine-disrupting compounds (EDCs) from all compound classes

Number of compounds detected 0 1 5 7 3 1 Minimum detected concentration (μg/L) 0 1.2 e0.13 e0.086 e0.032 0.84 Median detected concentration (μg/L) 0 1.2 e0.26 e0.69 e0.042 0.84 Maximum detected concentration (μg/L) 0 1.2 e2.0 2.3 e0.074 0.84 Total detected concentration (μg/L) 0 1.2 e3.0 e5.4 e0.15 0.84 Total load (lb/d) 0 e0.83 e0.027 e0.16 e0.0079 e1.3 

Table 8. Statistical summaries of analytical results and load results for organic wastewater compounds in wastewater effluent and the Big Sioux Riv

Brookings area.—Continued

[μg/L, micrograms per liter; lb/d, pounds per day; e, estimated; --, no data collected]

Station identification number and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent,

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent,

near Brookings, SD

(BK-DS1)

Big 
Table 9. Detected organic wastewater compounds in wastewater effluent and the Big Sioux River in the Brookings area.[Bold text for compound names indicates suspected endocrine-disrupting compounds (EDCs). AHTN, 7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydronaphthalene; HHCB, 1,3,4,6,7,

hexamethyl cyclopenta-g-2-benzopyran; NP2EO, nonylphenol diethoxylate; NP1EO, nonylphenol monoethoxylate; NP, para-nonylphenol; --, not detected]

Station identification number and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent,

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent,

near Brookings, SD

(BK-DS1)

Big 

Date of sample collection 08-21-2003 06-17-2004 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08Time of sample collection 1230 1140 0915 0950 1015 1215 Number of compounds detected 7 4 19 21 10 6 Human pharmaceutical compounds (HPCs) Caffeine

Cotinine

-- Cotinine

Dehydronifedipine

Cotinine Cotinine Caffeine

Cotinine

Cotin

Human and veterinary antibiotic compounds 

(HVACs)

-- ErythromycinH2O -- Ciprofloxacin Erythromycin

ErythromycinH2OOfloxacinSulfadiazineSulfamethazineSulfamethoxazoleTrimethoprim

-- ErythromycinH2O 

Major agricultural herbicides (MAHs) Prometon Atrazine

Metolachlor

Prometon Atrazine Prometon Atrazine

MetolachlorPrometon

Prom
Household, industrial, and minor agricultural 

use compounds (HIACs)

Tri(2-

butoxyethyl)

phosphate

Tri(2-

chloroethyl)

phosphate

N,N-diethylmetatoluamide 

(DEET)

5-methyl-1HbenzotriazoleAHTNAcetophenoneBenzophenoneBisphenol-AHHCBTributyl 

phosphate

TriclosanTriethyl citrate 

(ethyl citrate)

Triphenyl 

phosphate

Tri(2-

butoxyethyl)phosphate

Tri(2-

chloroethyl)phosphate

Tri(dichloroisopropyl)phosphate

5-methyl-1HbenzotriazoleAHTNBenzophenoneHHCBNP2EONP1EONPTributyl 

phosphate

Triethyl citrate 

(ethyl citrate)

Tri(2-

chloroethyl)phosphate

AHTNBenzophenoneHHCBTributyl 

phosphate

Tri(2-

chloroethyl)phosphate

Tri(dichloroisopropyl)phosphate

-- AHT

BenzHHCTribu

pho

Triet

(eth

Tri(2

chlo

pho

Tri(d

propha

PAH compounds (PAHs) -- -- -- -- -- -- Sterol compounds (SCs) beta-sitosterol

Cholesterol

-- 3-betacoprostanol

beta-sitosterolCholesterol

Cholesterol beta-sitosterol

Cholesterol

-- beta-

Chol

Table 9. Detected organic wastewater compounds in wastewater effluent and the Big Sioux River in the Brookings area.—Continued[Bold text for compound names indicates suspected endocrine-disrupting compounds (EDCs). AHTN, 7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydronaphthalene; HHCB, 1,3,4,6,7,

hexamethyl cyclopenta-g-2-benzopyran; NP2EO, nonylphenol diethoxylate; NP1EO, nonylphenol monoethoxylate; NP, para-nonylphenol; --, not detected]

Station identification number and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent,

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent,

near Brookings, SD

(BK-DS1)

Big 
NUMBER OF COMPOUNDS DETECTED

0

1.0

2.0

3.0

4.0

5.0

6.0

CONCENTRATION, IN MICROGRAMS PER LITER

0

1.0

0.5

2.0

1.5

LOAD, IN POUNDS PER DAY

SITE LABEL SITE LABEL

0

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

8

August 18-20, 2003 June 15-16, 2004

VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1 VL-DS2/

BK-US1

BK-WWE BK-DS2 BK-DS1

0

1.0

2.0

3.0

4.0

5.0

6.0

0

1.0

0.5

2.0

1.5

EXPLANATION

Major agricultural herbicides (MAHs)—Suspected

 of being endocrine disrupting compounds

Each bar represents the total sum of all compound classes. The part of a given bar indicated for each compound

 class represents the amount that compound class contributes to the total

Suspected endocrine disrupting compounds—From all

 compound classes (excluding major agricultural

 herbicides)

Synopsis of Results 51

Figure 14. Summary of results for endocrine-disrupting compounds (EDCs) from all compound classes in wastewater effluent and the 

Big Sioux River in the Brookings area.
52 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

In the upper Big Sioux River Basin, the location and size 

of the WWTPs relative to the flow of the Big Sioux River where 

the effluent is discharged clearly affects concentrations of 

OWCs in the Big Sioux River. Watertown is the largest city 

included in this study and has the largest capacity WWTP 

(table 1). Watertown is located near the upstream part of the Big 

Sioux River Basin, where the mean annual flow of the Big 

Sioux River is less than 100 ft3

/s. Watertown WWTP discharges commonly can account for greater than 50 percent of 

the flow of the Big Sioux River, especially during low-flow 

periods. Effects of the Watertown WWTP wastewater effluent 

discharges on the occurrence of OWCs in the Big Sioux River 

downstream were apparent during both the low-flow and runoff 

sampling periods. For Volga and Brookings, which are farther 

downstream in the Big Sioux River where the mean annual flow 

of the Big Sioux River exceeds 400 ft3

/s, wastewater effluent 

discharges from the Volga and Brookings WWTPs probably 

influenced the occurrence of OWCs in the Big Sioux River, but 

probably did not substantially contribute to total OWC concentrations or loads, especially during the runoff sampling period.

For the Watertown and Brookings areas, relative contributions from major probable sources of OWCs to the Big Sioux 

River at sites downstream from WWTP effluent discharges 

varied with different flow conditions. During low-flow conditions, OWCs that probably primarily were contributed by 

WWTP effluent discharges generally comprised a larger proportion of the total concentration of OWCs than during runoff 

conditions. During runoff conditions, OWCs that probably 

primarily were contributed by nonpoint source crop and animal 

agricultural sources generally comprised a larger proportion of 

the total concentration of OWCs than during low-flow conditions. Seasonal factors relating to timing of pesticide applications probably also contributed to this pattern. The combined 

effects of varied OWC sources and differences in the types of 

hydrologic conditions that govern the contributions from the 

OWC sources might result in moderate to substantial inputs of 

OWCs to the upper Big Sioux River under a wide range of flow 

conditions.

Occurrence of EDCs in aquatic systems is a very complex 

and sensitive issue. A complete assessment of potential effects 

of EDCs in the upper Big Sioux River based on the results of 

this study is not possible for several reasons. Sex hormones, 

which are the most potent EDCs, were not reported for this 

study. Also, a relatively small number of water-quality samples 

were collected in the Big Sioux River Basin during this study. 

WWTP effluent discharges vary with time, and concentrations 

of EDCs in wastewaters vary seasonally and interannually 

(Rodgers-Gray and others, 2000; Sheahan and others, 2002). 

Thus, it is very difficult to accurately quantify inputs of EDCs 

to the Big Sioux River Basin by determining EDC concentrations in a small number of samples collected during a single 

year. Also, mixtures of individual EDCs, like those that typically were found in samples collected in the upper Big Sioux 

River Basin, generally are believed to have the potential to act 

additively, but mixture effects are poorly understood (Sumpter 

and Johnson, 2005). Further, relatively few of the many organic 

compounds that might be present in WWTP effluents have been 

evaluated for potential endocrine-disrupting effects (Sumpter 

and Johnson, 2005). There might be EDCs that occur in the 

upper Big Sioux River for which there currently is no knowledge of endocrine-disrupting effects. For the EDCs that were 

determined in this study, total concentrations in water samples 

collected from the Big Sioux River downstream from WWTP 

effluents rarely exceeded 2 μg/L. It has been determined that 

some EDCs can have endocrine-disrupting effects at very low 

concentrations (near or less than 1 μg/L) and some mechanisms 

of endocrine disruption make it very difficult to define no-effect 

levels (Welshons and others, 2003). However, for most of the 

EDCs determined in this study, concentrations that result in 

substantial endocrine-disruption effects generally have been 

reported to be much larger than those observed in the Big Sioux 

River (Sumpter and Johnson, 2005).

Although this study cannot provide definitive assessment 

on EDC effects in the upper Big Sioux River Basin, a brief 

synopsis of research on the occurrence of EDCs in aquatic environments might be useful in providing a context for the EDC 

results for the upper Big Sioux River Basin and also to illustrate 

the complexity of the issue of EDCs in aquatic environments. 

Effects of endocrine disruptors in aquatic environments often 

are investigated by documenting atypical sexual characteristics 

in individual organisms (for example, occurrence of female 

biomarkers in male fish) but very few studies have conclusively 

documented that these effects actually result in either reduced 

reproductive potential of the individuals or negative effects on 

reproductive success at the population level (Sumpter and 

Jobling, 1995; Gies and others, 2001). Thus, few studies of 

EDCs conclusively indicate negative reproductive effects on 

aquatic ecosystems. However, in some studies, skewed sex 

ratios and gonadal histology indicate that individual and population level effects on reproductive success are possible 

(Desbrow and others, 1998).

Potential EDCs detected in the upper Big Sioux River 

Basin probably were derived from two general types of 

sources—WWTP discharges (the EDCs AHTN, benzophenone, 

bisphenol A, diethyl phthalate, HHCB, NP2EO, NP1EO, 

OP2EO, NP, and triclosan were detected in the upper Big Sioux 

River Basin and generally were attributable to WWTP discharges); and nonpoint crop agricultural sources (atrazine was 

detected in the upper Big Sioux River Basin and primarily is 

attributable to nonpoint agricultural crop sources). Research has 

been conducted on EDCs from both of these types of sources. 

Sex hormones, alkylphenols (APs), and AP ethoxylates generally have been implicated as the primary causative agents in 

WWTP effluents that result in estrogenic effects in aquatic 

organisms (Jobling and Sumpter, 1993; Desbrow and others, 

1998; Gies and others, 2001; Harris and others, 2001; and 

Jobling and Tyler, 2003). Sex hormones (primarily the natural 

and synthetic estrogens 17B estradiol and ethynyl estradiol) 

generally are regarded as the most potent EDCs, can produce 

substantial atypical sexual characteristics in fish at concentrations less than about 0.025 μg/L (Sumpter and Johnson, 2005), 

and in some studies have been implicated as the primary com-
Synopsis of Results 53

pounds contributing to feminization of male fish (Huggett and 

others, 2003) as a result of exposure to WWTP effluents. 

Analytical results for sex hormones for the upper Big Sioux 

River Basin are not reported for this study. However, sex hormones commonly are found in WWTP effluent discharges, so it 

is possible that they occur in the upper Big Sioux River.

AP ethoxylates and their shorter chain metabolites are 

complex nonionic surfactants. Of the various APs and AP 

ethoxylates, nonylphenol and octylphenol appear to have the 

largest endocrine-disrupting activities, and have shown substantial estrogenic activity at concentrations in the range of 

about 8 to 10 μg/L (Jobling and others, 1996; Harris and others, 

2001). APs and AP ethoxylates detected in the upper Big Sioux 

River Basin at concentrations greater than the SRL include 

NP2EO, NP1EO, NP, and OP2EO. The largest combined concentration for these compounds in any water sample collected 

from the Big Sioux River was 5.8 μg/L, which is less than the 

reported endocrine disruption substantial-effect level of even 

the most potent individual AP (Sumpter and Johnson, 2005).

Other WWTP-sourced EDCs in the Big Sioux River Basin 

have shown endocrine-disrupting effects in various laboratory 

studies, but generally are not implicated as major causative 

agents of endocrine disruption in aquatic organisms in field 

studies. The other WWTP-sourced EDCs detected in the Big 

Sioux River Basin that have shown endocrine-disrupting effects 

include: AHTN (Bitsch and others, 2002; Richard and others, 

2002; Richard and others, 2004); benzophenone (Schlumpf and 

others, 2001); bisphenol A (Jobling and others, 1995; Jobling 

and others, 1998; Andersen and others, 1999; Fisher and others, 

1999; Oehlmann and others, 2000; Sheehan, 2000; Rajapakse 

and others, 2001; and Sohoni and others, 2001); diethyl phthalate (Jobling and others, 1995; Harris and others, 1997; Jobling 

and others, 1998), HHCB (Richard and others, 2002; Richard 

and others, 2004); and triclosan (Foran and others, 2000; Latch 

and others, 2003). Generally, these compounds have much less 

potent endocrine disruptive effects than either sex hormones or 

APs and AP ethoxylates, with substantial effect levels based on 

laboratory studies generally exceeding 50 μg/L (Richard and 

others, 2004; Sumpter and Johnson, 2005). The maximum concentration found in any water sample collected from the Big 

Sioux River for any of these compounds was 0.59 μg/L (AHTN 

was detected at this concentration in a water sample collected 

from WT-DS1).

Although it is not possible to definitively assess the effects 

of WWTP EDCs from the data that were collected in the upper 

Big Sioux River Basin, studies performed in the United Kingdom might provide information that could help in evaluating the 

potential for WWTP-related endocrine disruption effects in the 

Big Sioux River Basin. From these studies, researchers have 

concluded that EDCs are present in most, if not all, treated sewage effluents (Jobling and Tyler, 2003). Dilution effects from 

introduction of the WWTP effluents into receiving streams 

substantially reduce the effects of the EDCs present in sewage 

effluents. British research on a variety of types of WWTPs has 

found that WWTP effluents start to show statistically significant estrogenic effects in fish populations in receiving waters 

when the WWTP effluent accounts for between about 25 and 

50 percent of the total flow of the receiving water (Harries and 

others, 1999; Rodgers-Gray and others, 2000) for relatively 

short periods (about 1 month). Further, when the time of exposure is increased to 4 months, significant estrogenic effects 

occurred when the WWTP effluent accounted for as little as 

10 percent of the total flow of the receiving water (RodgersGray and others, 2000). Based on these observations, it is possible that the WWTP effluents in the Big Sioux River might 

produce estrogenic effects in aquatic organisms. This is especially true for the Watertown area, because the Watertown 

WWTP effluent commonly accounts for greater than 25 percent 

of the downstream flow of the Big Sioux River for extended 

periods of time (that is, several months). For example, assuming 

an average discharge from the Watertown WWTP of 4 ft3

/s, 

during water years 1977 through 2004, this level of effluent 

discharge would have accounted for about 25 percent or more 

of the flow of the Big Sioux River about 45 percent of the time, 

and would have accounted for about 10 percent or more of the 

flow of the Big Sioux River about 65 percent of the time. Based 

on these observations, it is possible that the Watertown WWTP 

effluent discharges to the Big Sioux River might produce 

endocrine-disrupting effects in aquatic organisms. However, it 

should be noted that concentrations and loads of EDCs 

decreased substantially between sites WT-DS1 and WT-DS2, 

so any endocrine-disrupting effects on organisms in the Big 

Sioux River resulting from WWTP effluent discharges probably would be restricted to a relatively short reach. Also, results 

of studies conducted in Britain on potential estrogenic effects of 

WWTP effluents on fish populations in receiving waters do not 

necessarily have direct application in the Big Sioux River Basin 

primarily because: (1) wastewater treatment technologies and 

types of raw sewage inputs to different WWTPs vary substantially and result in large variability in EDC concentrations in 

WWTP effluents; and (2) EDC effects on fish are species 

dependent (Sumpter and Johnson, 2005), and fish species 

present in the Big Sioux River Basin are different than the fish 

species studied in the United Kingdom and might respond 

differently to EDC exposure.

Atrazine is a herbicide contributed to the Big Sioux River 

primarily from nonpoint crop agricultural sources and has been 

implicated in both field and laboratory studies as having 

endocrine-disrupting effects on aquatic organisms (Hayes and 

others, 2003; Spano and others, 2004). Atrazine exposure has 

been reported to result in reproductive abnormalities in frogs at 

concentrations as small as 0.1 μg/L (Hayes and others, 2003), 

but reported effect levels for fish generally are substantially 

larger. Spano and others (2004) reported gonadal abnormalities 

in fish exposed to atrazine at a concentration of 100 μg/L. 

Bringolf and others (2004) reported lower egg production in fathead minnows exposed to atrazine at a concentration of 

0.5 μg/L; however, the results were not found to be statistically 

significant. Based on the lack of definitive research establishing 

endocrine-disruptive effect levels for atrazine, it is not possible 

to assess whether atrazine concentrations detected in Big Sioux 

River samples might have the potential for endocrine disruption 

of aquatic organisms.
54 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Summary and Conclusions

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

the East Dakota Water Development District conducted a 

reconnaissance study to determine the occurrence of organic 

wastewater compounds (OWCs) in wastewater effluent and the 

Big Sioux River in the upper Big Sioux River Basin during 

August 2003 through June 2004. Water samples were collected 

at 12 sites to investigate the occurrence of OWCs in wastewater 

effluent and the Big Sioux River at or near the cities of Watertown, Volga, and Brookings. For each city, samples were collected from the wastewater treatment plant (WWTP) effluent, 

and from the Big Sioux River at sites upstream and downstream 

from where the wastewater effluent enters the Big Sioux River. 

For Watertown and Brookings, samples were collected during a 

low-flow period (August 2003) and a runoff period (June 2004). 

For Volga, samples were collected during two low-flow periods 

(August 2003 and October 2003) and a runoff period (June 

2004).

A total of 125 different OWCs were analyzed for in this 

study using three different analytical methods. Analyses for 

OWCs were performed at USGS laboratories that are developing and/or refining small-concentration (less than 1 microgram 

per liter (μg/L)) analytical methods. The OWCs analyzed for in 

this study are classified into the following six compound 

classes: (1) human pharmaceutical compounds (HPCs), which 

are commonly used prescription and non-prescription pharmaceutical drugs; (2) human and veterinary antibiotic compounds 

(HVACs), which are prescription drugs used in the treatment of 

infectious diseases; (3) major agricultural herbicides (MAHs), 

which include atrazine, metolachlor, and prometon; (4) household, industrial, and minor agricultural compounds (HIACs), 

which are various generally synthetic organic compounds used 

for a variety of purposes, including detergents, fire retardants, 

plasticizers, fragrances, solvents, preservatives, and disinfectants); (5) polyaromatic hydrocarbons (PAHs), which are compounds often occurring in fossil fuels or produced by the combustion of fossil fuels; and (6) sterol compounds (SCs), which 

are predominantly unsaturated solid alcohols of the steroid 

group naturally occurring in fatty tissues of plants and animals 

and present in animal fecal material. Some of the compounds in 

the HPC, MAH, HIAC, and PAH classes are suspected of being 

endocrine-disrupting compounds (EDCs). Of the 125 different 

OWCs analyzed for in this study, 73 OWCs had one or more 

detections in environmental samples reported by the laboratories, and of those 73 OWCs, 45 had acceptable analytical 

method performance, were detected at concentrations greater 

than the study reporting levels, and were included in analyses 

and discussion related to occurrence of OWCs in wastewater 

effluents and the Big Sioux River.

OWCs in all compound classes were detected in water 

samples collected in August 2003 and June 2004 from sampling 

sites in the Watertown area. The Watertown WWTP discharged 

continuously to the Big Sioux River during both sampling 

periods. Total OWC concentrations for upstream Big Sioux 

River sites generally were small, less than about 6 μg/L for both 

sampling periods. SCs accounted for nearly all of the total 

OWC concentration for upstream Big Sioux River sites for the 

August 2003 sample, and MAHs accounted for nearly all of the 

total OWC concentrations for the June 2004 sample. Total 

OWC concentrations for the Watertown wastewater effluent 

(WT-WWE) were relatively large for both sampling periods. 

Major OWC classes contributing to total OWC concentrations 

for WT-WWE included HIACs, SCs, and HVACs. Total OWC 

concentrations for downstream site WT-DS1 were relatively 

large for August 2003 and smaller for June 2004, and probably 

reflect a greater fraction of the total flow of the Big Sioux River 

being derived from WWTP discharge during the August 2003 

sampling period. Major OWC classes contributing to total 

OWC concentrations for WT-DS1 were HIACs, SCs, and 

HVACs. Total OWC concentrations were substantially smaller 

for the most downstream site WT-DS2 than for WT-WWE and 

WT-DS1. Major OWC classes contributing to total OWC concentrations for WT-DS2 were SCs, HIACs, and HVACs. 

Although confident conclusions could not be made because of 

possible effects of non-Lagrangian sampling, OWC results for 

the Watertown area might indicate that (1) OWCs for upstream 

Big Sioux River sites probably were primarily contributed by 

nonpoint source agricultural sources, with livestock agriculture 

accounting for most of the total OWC concentration for the 

August 2003 (low-flow) sampling period, and crop agriculture 

accounting for most of the total OWC concentration for the June 

2004 (runoff) sampling period; (2) OWCs for downstream Big 

Sioux River sites were strongly influenced by contributions 

from the Watertown WWTP during both the August 2003 (lowflow) and June 2004 (runoff) sampling periods; and (3) contributions of OWCs that might be derived from nonpoint livestock 

agricultural sources accounted for a larger proportion of OWCs 

for WT-DS2 than for WT-DS1 for both the August 2003 (lowflow) and June 2004 (runoff) sampling periods. EDCs were 

detected in all Big Sioux River samples in the Watertown area. 

For both August 2003 and June 2004, the numbers of EDCs 

detected, and EDC concentrations and loads generally were 

larger in samples from downstream Big Sioux River sites than 

from upstream Big Sioux River sites. Total estimated EDC concentrations ranged from 0.19 to 0.55 μg/L for upstream Big 

Sioux River sites and consisted mostly of HIACs for low-flow 

samples and MAHs for runoff samples. Total estimated EDC 

concentrations for downstream Big Sioux River sites ranged 

from about 0.32 to 2.5 μg/L, and consisted mostly of HIACs 

for low-flow samples and both HIACs and MAHs for runoff 

samples.

OWCs in all compound classes except PAHs were 

detected in samples from sites in the Volga area. For the August 

2003 and June 2004 sampling periods, the Volga WWTP was 

not discharging to the Big Sioux River, but for the October 2003 

sampling period, the Volga WWTP was discharging continuously to the Big Sioux River. For August 2003, the upstream 

Big Sioux River site had larger total OWC concentrations and 

loads than downstream Big Sioux River sites, and SCs 

accounted for most of the total OWC concentration for all Big 
Summary and Conclusions 55

Sioux River sites. For October 2003, when the Volga WWTP 

was discharging to the Big Sioux River channel, total OWC 

concentrations and loads were larger for the downstream Big 

Sioux River site, than for the upstream site and the increase in 

load corresponds well with the load contributed by the Volga 

wastewater effluent discharge, especially for HIACs. HIACs 

and SCs accounted for most of the total OWC concentration for 

Big Sioux River sites. For June 2004, the upstream site had 

smaller total OWC concentrations and loads than downstream 

Big Sioux River sites. MAHs accounted for most of the total 

OWC concentrations for Big Sioux River sites. Although confident conclusions cannot be made due to possible effects of 

non-Lagrangian sampling, the data might indicate that (1) for 

the August 2003 sampling period, nonpoint livestock agricultural and/or human wastewater sources might have been the 

primary contributor to occurrence of OWCs at Big Sioux River 

sampling sites; (2) for the October 2003 sampling period, nonpoint livestock sources and upstream human wastewater 

sources primarily contributed to the occurrence of OWCs at Big 

Sioux River sampling sites; (3) for the June 2004 sampling 

period, nonpoint crop agricultural sources primarily contribute 

to occurrence of OWCs at Big Sioux River sampling sites; 

(4) for the August 2003 and June 2004 sampling periods, seepage of water from the Volga WWTP had little effect on downstream OWC concentrations; and (5) for the October 2003 

sampling period, the Volga wastewater effluent discharge contributed to downstream OWC concentrations. EDCs were 

detected in all samples collected from sampling sites in the 

Volga area. For all sampling periods, total EDC concentrations 

generally were similar between upstream and downstream Big 

Sioux River sites. Total estimated EDC concentrations for the 

upstream site ranged from 0.069 to 5.2 μg/L and consisted of 

HIACs and MAHs. Total estimated EDC concentrations for 

downstream sites ranged from undetected to 5.8 μg/L and consisted of HIACs and MAHs. HIACs accounted for most of the 

total EDC concentrations for the August 2003 and October 

2003 sampling periods, and MAHs accounted for most of the 

total EDC concentrations for the June 2004 sampling period for 

all Big Sioux River sites.

OWCs in all compound classes except PAHs were 

detected in water samples collected in August 2003 and June 

2004 from sampling sites in the Brookings area. The Brookings 

WWTP discharged continuously to the Big Sioux River during 

both sampling periods. For August 2003, the upstream site had 

slightly smaller total OWC concentrations and loads compared 

to the downstream Big Sioux River sites. SCs and HIACs 

accounted for most of the total OWC concentrations in all Big 

Sioux River sampling sites, but the proportion of SCs increased 

at the most downstream site. For June 2004, the upstream site 

generally had smaller total OWC concentrations and loads than 

downstream Big Sioux River sites. MAHs accounted for most 

of the total OWC concentrations for all Big Sioux River sites, 

but the proportion of SCs increased at the most downstream 

site. Although confident conclusions could not be made due to 

possible effects of non-Lagrangian sampling, the data might 

indicate that (1) for the August 2003 sampling period, nonpoint 

livestock agricultural and/or human wastewater sources probably primarily contributed to occurrence of OWCs at all Big 

Sioux River sampling sites, and the Brookings WWTP wastewater effluent discharge contributed but did not have a substantial effect on concentrations at downstream sites; (2) for the 

June 2004 sampling period, nonpoint crop agricultural and/or 

human wastewater sources primarily contributed to occurrence 

of OWCs at all of the Big Sioux River sites, a substantial 

amount of SCs were contributed to the Big Sioux River downstream between BK-DS1 and BK-DS2, and the Brookings 

WWTP wastewater effluent discharge probably did not substantially contribute to total OWC concentrations at downstream sampling sites. EDCs were detected in all samples 

collected from sampling sites in the Brookings area. Total estimated EDC concentrations for one sample from the upstream 

site was 1.2 μg/L and consisted of MAHs. Total estimated EDC 

concentrations for downstream sites ranged from 0.15 to 

1.3 μg/L and consisted of MAHs and HIACs. HIACs accounted 

for all of the total EDC concentrations for the August 2003 

sampling period, and MAHs accounted for all of the total EDC 

concentrations for the June 2004 sampling period for downstream Big Sioux River sites.

Detected concentrations of individual OWCs found in 

water samples collected from the Big Sioux River generally 

were within ranges of concentrations reported for other streams 

in the United States. However, concentrations of some HVACs 

(including ciprofloxacin, erythromycin-H2O, sulfamethoxazole, and trimethoprim) in water samples collected from the 

Big Sioux River downstream from Watertown generally were 

large relative to reported concentrations for other streams in the 

United States.

In the upper Big Sioux River Basin, the location and size 

of the WWTPs relative to the discharge of the Big Sioux River 

where the effluent is discharged clearly affects concentrations 

of OWCs in the Big Sioux River. The city of Watertown is 

located near the upstream part of the Big Sioux River Basin, 

where the mean annual flow of the Big Sioux River is less than 

100 ft3/s. Watertown WWTP discharges can account for a 

substantial part of the flow in the Big Sioux River, especially 

during low-flow periods. Effects of the Watertown WWTP 

wastewater effluent discharges on the occurrence of OWCs in 

the Big Sioux River downstream were apparent during both 

the low-flow and runoff sampling periods. For Volga and 

Brookings, which are farther downstream in the Big Sioux 

River where the mean annual flow of the Big Sioux River 

exceeds 400 ft3/s, wastewater effluent discharges from the 

Volga and Brookings WWTPs probably influenced the occurrence of OWCs in the Big Sioux River, but probably did not 

substantially contribute to total OWC concentrations, especially 

during the runoff sampling period.

For the Watertown and Brookings areas, relative contributions from major probable sources of OWCs to the Big Sioux 

River at sites downstream from WWTP effluent discharges 

varied with different flow conditions. During low-flow 

conditions, OWCs that probably primarily were contributed by 

WWTP effluent discharges generally comprised a larger pro-
56 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

portion of the total concentration of OWCs than during runoff 

conditions. During runoff conditions, OWCs that probably 

primarily were contributed by nonpoint source crop and animal 

agricultural sources generally comprised a larger proportion of 

the total concentration of OWCs than during low-flow conditions. Seasonal factors related to timing of pesticide applications probably also contributed to this pattern. The combination 

of the different major sources of OWCs in the upper Big Sioux 

River might result in maintenance of fairly substantial levels of 

OWCs under a wide range in flow conditions.

Occurrence of EDCs in aquatic systems is a very complex 

and sensitive issue. Accurate assessment of potential effects of 

EDCs in the upper Big Sioux River based on the results of this 

study is not possible.

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Supplemental Information

Supplemental Information 61

Table 10. Field-measured properties and constituents and analytical constituents.

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source

Field-measured properties and constituents

Gage height -- -- 0.01 ft 0.01 ft -- --

Discharge, instantaneous -- -- 0.1 ft3/s 0.1 ft3/s -- --

Turbidity -- -- 1 NTU 1 NTU -- --

Barometric pressure -- -- 1 mm Hg 1 mm Hg -- --

Dissolved oxygen -- -- 0.1 mg/L 0.1 mg/L -- --

pH -- -- 0.1 standard 

unit

0.1 standard 

unit

-- --

Specific conductance -- -- 5 μS/cm 5 μS/cm -- --

Air temperature -- -- 0.1°C 0.1°C -- --

Water temperature -- -- 0.1°C 0.1°C -- --

Auxiliary constituents

Nitrite plus nitrate nitrogen -- -- 0.06 mg/L 0.06 mg/L -- --

Total coliform concentration, most 

probable number

-- -- 10 col/100 mL 10 col/100 mL -- --

Fecal coliform concentration, 

membrane filter

-- -- 10 col/100 mL 10 col/100 mL -- --

Human pharmaceutical compounds (HPCs)

1,7-dimethylxanthine, dissolved 2 1 0.144 0.05 611-59-6 caffeine metabolite

Acetaminophen, dissolved 2, 3 1 0.036 ND 103-90-2 antipyretic (nonprescription)

Caffeine, dissolved 1, 4 1 0.016 0.022 58-08-2 stimulant (nonprescription)

Caffeine, whole water 1 3 0.5 0.12 58-08-2 stimulant (nonprescription)

Carbamazepine, dissolved 1, 3 1 0.011 ND 298-46-4 anticonvulsant, antineuralgic 

(prescription)

Cimetidine, dissolved 1, 3 1 0.012 ND 51481-61-9 antacid (nonprescription)

Codeine, dissolved 1, 3 1 0.015 ND 76-57-3 analgesic (prescription)

Cotinine, dissolved 1, 4 1 0.014 0.0008 486-56-6 nicotine metabolite

Cotinine, whole water 1 3 1 0.18 486-56-6 nicotine metabolite

Dehydronifedipine, dissolved 1, 4 1 0.015 0.0035 67035-22-7 antianginal (prescription)

Diltiazem, dissolved 1, 3 1 0.016 ND 42399-41-7 antihypertensive (prescription)

Diphenhydramine, dissolved 1, 3 1 0.015 ND 58-73-1 antihistamine (prescription)

Fluoxetine, dissolved 2, 3 1 0.014 ND 54910-89-3 antidepressant (prescription)

Furosemide, dissolved 2, 3 1 0.039 ND 54-31-9 diuretic (prescription)
62 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Human pharmaceutical compounds (HPCs)—Continued

Gemfibrozil, dissolved 2, 3 1 0.013 ND 25812-30-0 antihyperlipidemic (prescription)

Ibuprofen, dissolved 2, 3 1 0.042 ND 15687-27-1 anti-inflamatory (nonprescription)

Metformin, dissolved 2, 3 1 ND ND 1115-70-4 antidiabetic (prescription)

Miconazole, dissolved 2, 3 1 0.018 ND 22916-47-8 antifungal (nonprescription)

Ranitidine, dissolved 1, 3 1 0.013 ND 66357-35-5 antacid (nonprescription)

Salbutamol, dissolved 1, 4 1 0.023 0.0054 18559-94-9 antiasthmatic (prescription)

Thiabendazole, dissolved 2, 3 1 0.011 ND 148-79-8 human and veterinary 

antihelminthic (prescription)

Warfarin, dissolved 2, 3 1 0.012 ND 81-81-2 anticoagulant (prescription)

Human and veterinary antibiotic compounds (HVACs)

Amoxicilin, dissolved 2 2 0.01 0.05 26787-78-0 antibiotic (human and veterinary; 

penicillin class)

Ampicillin, dissolved 2 2 0.01 0.01 69-53-4 antibiotic (human and veterinary; 

penicillin class)

Anhd-Cl-tetracycline, dissolved 2 2 0.01 0.3 13803-65-1 tetracycline metabolite

Anhydrotetracycline, dissolved 2 2 0.01 0.15 -- tetracycline metabolite

Azithromycin, dissolved 2, 3 1 0.004 ND 83905-01-5 antibiotic (human and veterinary; 

macrolide class)

Cefotaxime, dissolved 2 2 0.01 0.01 63527-52-6 antibiotic (human and veterinary; 

cephalosporin class)

Chlorotetracycline, dissolved 2 2 0.01 0.05 57-62-5 antibiotic (veterinary; tetracycline 

class)

Ciprofloxacin, dissolved 1, 4 2 0.005 0.036 85721-33-1 antibiotic (human and veterinary; 

fluoroquinolone class)

Clinafloxacin, dissolved 2 2 0.005 0.01 105956-97-6 antibiotic (human and veterinary; 

fluoroquinolone class)

Cloxacillin, dissolved 2 2 0.01 0.01 61-72-3 antibiotic (human and veterinary; 

penicillin class)

Demeclocycline, dissolved 2 2 0.01 0.08 127-33-3 antibiotic (human and veterinary; 

tetracycline class)

Doxycycline, dissolved 2 2 0.01 0.05 564-25-0 antibiotic (human and veterinary; 

tetracycline class)

Erythromycin (method 1), dissolved 2, 3 1 0.009 ND 114-07-8 antibiotic (human and veterinary; 

macrolide class)

Erythromycin (method 2), dissolved 1, 4 2 0.02 0.025 114-07-8 antibiotic (human and veterinary; 

macrolide class)

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
Supplemental Information 63

Human and veterinary antibiotic compounds (HVACs)—Continued

Erythromycin-H2O, dissolved 1, 4 2 0.005 0.046 114-07-8 erythromycin metabolite

Flumequine, dissolved 2 2 0.005 0.005 42835-25-6 antibiotic (veterinary; 

fluoroquinolone class)

Lincomycin, dissolved 2 2 0.005 0.005 154-21-2 antibiotic (veterinary; lincosamide 

class)

Lomefloxacin, dissolved 2 2 0.005 0.005 98079-51-7 antibiotic (veterinary; 

fluoroquinolone class)

Minocycline, dissolved 2 2 0.01 0.25 10118-90-8 antibiotic (human and veterinary; 

tetracycline class)

Norfloxacin, dissolved 1, 4 2 0.005 0.02 70458-96-7 antibiotic (human and veterinary; 

fluoroquinolone class)

Ofloxacin, dissolved 1, 4 2 0.005 0.03 83380-47-6 antibiotic (human and veterinary; 

fluoroquinolone class)

Ormetoprim, dissolved 2 2 0.005 0.005 6981-18-6 antibiotic (veterinary; sulfonamide 

class)

Oxacillin, dissolved 2 2 0.01 0.01 66-79-5 antibiotic (human and veterinary; 

penicillin class)

Oxolinic acid, dissolved 2 2 0.005 0.005 14698-29-4 antibiotic (veterinary; 

fluoroquinolone class)

Oxytetracycline, dissolved 2 2 0.01 0.15 79-57-2 antibiotic (veterinary; tetracycline 

class)

Penicillin G, dissolved 2 2 0.01 0.01 69-57-8 antibiotic (human and veterinary; 

penicillin class)

Penicillin V, dissolved 2 2 0.01 0.01 87-08-1 antibiotic (human and veterinary; 

penicillin class)

Roxithromycin, dissolved 1, 4 2 0.005 0.005 80214-83-1 antibiotic (human and veterinary; 

macrolide class)

Sarafloxacin, dissolved 2 2 0.005 0.03 98105-99-8 antibiotic (veterinary; 

fluoroquinolone class)

Sulfachlorpyridazine, dissolved 2 2 0.005 0.005 80-32-0 antibiotic (veterinary; sulfonamide 

class)

Sulfadiazine, dissolved 1, 4 2 0.005 0.005 68-35-9 antibiotic (veterinary; sulfonamide 

class)

Sulfadimethoxine, dissolved 2 2 0.005 0.005 122-11-2 antibiotic (veterinary; sulfonamide 

class)

Sulfamerazine, dissolved 2 2 0.005 0.005 127-79-7 antibiotic (veterinary; sulfonamide 

class)

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
64 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Human and veterinary antibiotic compounds (HVACs)—Continued

Sulfamethazine, dissolved 1, 4 2 0.005 0.005 57-68-1 antibiotic (veterinary; sulfonamide 

class)

Sulfamethoxazole (method 1), 

dissolved

1, 3 1 0.064 ND 723-46-6 antibiotic (human and veterinary; 

sulfonamide class)

Sulfamethoxazole (method 2), 

dissolved

1, 4 2 0.005 0.02 723-46-6 antibiotic (human and veterinary; 

sulfonamide class)

Sulfathiazole, dissolved 2 2 0.005 0.005 72-14-0 antibiotic (veterinary; sulfonamide 

class)

Tetracycline, dissolved 1, 4 2 0.01 0.064 60-54-8 antibiotic (human and veterinary; 

tetracycline class)

Trimethoprim (method 1), dissolved 1, 3 1 0.013 ND 738-70-5 antibiotic (human and veterinary; 

folic acid inhibitor class)

Trimethoprim (method 2), dissolved 1, 4 2 0.01 0.02 738-70-5 antibiotic (human and veterinary; 

folic acid inhibitor class)

Tylosin, dissolved 2 2 0.005 0.07 1401-69-0 antibiotic (veterinary; macrolide 

class)

Virginiamycin, dissolved 2 2 0.005 0.005 21411-53-0 antibiotic (veterinary; 

streptogramin class)

Major agricultural herbicides (MAHs)

Atrazine, whole water 1, 4 3 0.5 0.0002 1912-24-9 herbicide

Metolachlor, whole water 1, 4 3 0.5 0.028 98-82-8 herbicide

Prometon, whole water 1, 4 3 0.5 0.02 1610-18-0 herbicide

Household, industrial, and minor agricultural-use compounds (HIACs)

1,4-dichlorobenzene, whole water 2, 3 3 0.5 ND 106-46-7 deodorizer, moth repellent

2,2’,4,4’-tetrabromodiphenyl ether, 

whole water

2 3 0.5 0.5 5436-43-1 fire retardant

3,4-dichlorophenyl isocyanate, whole 

water

2, 3 3 0.5 ND 102-36-3 manufacturing intermediate

3-methyl-1H-indole (skatol), whole 

water

2 3 1 0.02 83-34-1 fragrance

3-tert-butyl-4-hydroxy anisole 

(BHA), whole water

2, 3 3 5 ND 121-00-6 antioxidant

4-cumylphenol, whole water 2 3 1 1 599-64-4 detergent metabolite

4-normal-octylphenol, whole water 2 3 1 1 1806-26-4 detergent metabolite

4-tert-octylphenol, whole water 2 3 1 0.26 140-66-9 detergent metabolite

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
Supplemental Information 65

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

5-methyl-1H-benzotriazole, whole 

water

1, 4 3 2 0.33 136-85-6 anticorrosive

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene (AHTN), 

whole water

1, 4 3 0.5 0.048 21145-77-7 fragrance

Acetophenone, whole water 1, 4 3 0.5 0.08 98-86-2 fragrance

Anthraquinone, whole water 2 3 0.5 0.96 84-65-1 manufacturing, pesticide

Benzophenone, whole water 1, 4 3 0.5 0.025 119-61-9 fixative

Bis(2-ethylhexyl) phthalate, whole 

water

2, 3 3 2 ND 117-81-7 plasticizer

Bisphenol-A, whole water 1, 4 3 1 0.069 80-05-7 plasticizer

Bromacil, whole water 2 3 0.5 0.068 314-40-9 herbicide

Camphor, whole water 1, 4 3 0.5 0.07 76-22-2 fumigant and flavorant

Carbaryl, whole water 2, 3 3 1 ND 63-25-2 insecticide

Chlorpyrifos, whole water 2 3 0.5 0.5 2921-88-2 insecticide

N,N-diethyl-meta-toluamide (DEET), 

whole water

1, 4 3 0.5 0.08 134-62-3 insect repellent

Diazinon, whole water 2 3 0.5 0.027 333-41-5 insecticide

Dichlorvos, whole water 2 3 1 1 62-73-7 insecticide

Diethyl phthalate, whole water 1, 4 3 0.5 0.55 84-66-2 plasticizer

D-Limonene, whole water 2, 3 3 0.5 ND 5989-27-5 solvent

1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-

hexamethyl cyclopenta-g-2-

benzopyran (HHCB), whole water

1, 4 3 0.5 0.032 1222-05-5 fragrance

Indole, whole water 1, 4 3 0.5 0.015 120-72-9 amino-acid metabolite

Isoborneol, whole water 2 3 0.5 0.5 124-76-5 fragrance, flavorant

Isophorone, whole water 1, 4 3 0.5 0.047 78-59-1 solvent

Isoquinoline, whole water 2 3 0.5 0.5 119-65-3 manufacturing

Menthol, whole water 2 3 0.5 0.5 89-78-1 pharmaceutical additive, fragrance

Metalaxyl, whole water 2 3 0.5 0.5 57837-19-1 agricultural fungicide

Methyl salicylate, whole water 2 3 0.5 0.5 119-36-8 flavoring agent, liniment

Nonylphenol diethoxylate (NP2EO), 

whole water

1, 4 3 5 0.55 26027-38-2 detergent/surfactant or metabolite

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
66 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

Nonylphenol monoethoxylate 

(NP1EO), whole water

1, 4 3 2 0.39 27986-36-3 detergent/surfactant or metabolite

Octylphenol diethoxylate (OP2EO), 

whole water

1, 4 3 1 0.14 26636-32-8 detergent/surfactant or metabolite

Octylphenol monoethoxylate 

(OP1EO), whole water

2 3 1 1 26636-32-8 detergent/surfactant or metabolite

para-cresol, whole water 1, 4 3 1 0.03 106-44-5 wood preservative

para-nonylphenol (NP), whole water 1, 4 3 5 0.64 84852-15-3 detergent/surfactant or metabolite

Pentachlorophenol, whole water 2 3 2 2 87-86-5 wood preservative

Phenol, whole water 2 3 0.5 0.94 108-95-2 resin and pharmaceutical 

manufacturing, disinfectant,

Tetrachloroethylene, whole water 2, 3 3 0.5 ND 127-18-4 solvent, degreaser

Tributyl phosphate, whole water 1, 4 3 0.5 0.02 126-73-8 fire retardant

Triclosan, whole water 1, 4 3 1 0.084 3380-34-5 antimicrobial disinfectant

Triethyl citrate (ethyl citrate), whole 

water

1, 4 3 0.5 0.048 77-93-0 cosmetics

Triphenyl phosphate, whole water 1, 4 3 0.5 0.015 115-86-6 plasticizer

Tri(2-butoxyethyl)phosphate, whole 

water

1, 4 3 0.5 0.13 78-51-3 plasticizer

Tri(2-chloroethyl)phosphate, whole 

water

1, 4 3 0.5 0.056 115-96-8 fire retardant

Tri(dichloroisopropyl)phosphate, 

whole water

1, 4 3 0.5 0.047 13674-87-8 fire retardant

Polyaromatic hydrocarbons (PAHs)

1-methylnaphthalene, whole water 2 3 0.5 0.5 90-12-0 fossil fuel combustion

2,6-dimethylnaphthalene, whole 

water

2 3 0.5 0.5 58-14-2 fossil fuel combustion

2-methylnaphthalene, whole water 2 3 0.5 0.5 91-57-6 fossil fuel combustion

Anthracene, whole water 2 3 0.5 0.5 120-12-7 preservative, component of tar

Benzo[a]pyrene, whole water 2 3 0.5 0.5 50-32-8 fossil fuel combustion

Carbazole, whole water 2 3 0.5 0.22 86-74-8 chemical manufacturing

Fluoranthene, whole water 2 3 0.5 0.15 206-44-0 component of coal tar and asphalt

Isopropylbenzene (cumene), whole 

water

2, 3 3 0.5 ND 98-82-8 fuels and paint thinners

Naphthalene, whole water 1, 4 3 0.5 0.01 91-20-3 moth repellent, major component 

in gasoline

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
Supplemental Information 67

Polyaromatic hydrocarbons (PAHs)—Continued

Phenanthrene, whole water 2 3 0.5 0.1 85-01-8 fossil fuel combustion

Pyrene, whole water 2 3 0.5 0.04 129-00-0 fossil fuel combustion

Sterol compounds (SCs)

3-beta-coprostanol, whole water 1, 4 3 2 0.26 360-68-9 fecal sterol

beta-sitosterol, whole water 1, 4 3 2 0.57 83-46-5 plant sterol

beta-stigmastanol, whole water 2, 3 3 2 ND 19466-47-8 plant sterol

Cholesterol, whole water 1, 4 3 2 0.64 57-88-5 plant/animal sterol

Laboratory quality-assurance/quality-control surrogate compounds

Bisphenol-A-d3 (surrogate), whole 

water

-- 3 0.1 percent 

recovery

0.1 percent 

recovery

-- laboratory analytical surrogate

Bisphenol-A-d3 (surrogate), whole 

water

-- 3 0.1 percent 

recovery

0.1 percent 

recovery

-- laboratory analytical surrogate

Caffeine-c13 (surrogate), whole water -- 3 0.1 percent 

recovery

0.1 percent 

recovery

-- laboratory analytical surrogate

Decafluorobiphenyl (surrogate), 

whole water

-- 3 0.1 percent 

recovery

0.1 percent 

recovery

434-90-2 laboratory analytical surrogate

Ethyl-nicontinate-d4 (surrogate), 

dissolved

-- 1 0.1 percent 

recovery

0.1 percent 

recovery

-- laboratory analytical surrogate

Fluoranthene-d10 (surrogate), whole 

water

-- 3 0.1 percent 

recovery

0.1 percent 

recovery

93951-69-0 laboratory analytical surrogate

1Constituent detected in one or more environmental samples at concentration(s) greater than study reporting level.

2Constituent not detected in any environmental samples at concentration(s) greater than study reporting level.

3

Results for laboratory reagent-spike samples and/or matrix-spike samples unacceptable; constituent excluded from analyses.

4Constituent included in summary analyses and discussion related to occurrence of organic wastewater compounds in wastewater effluent.

Table 10. Field-measured properties and constituents and analytical constituents.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Units are micrograms per liter unless otherwise noted. CAS RN, Chemical Abstracts 

Service Registry Number; ft, feet; ft3

/s, cubic feet per second; mm Hg, millimeter of mercury; mg/L, milligrams per liter; μg/L, micrograms per liter; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degree Celsius; col/100 mL, colonies per 100 milliliters; NTU, Nephelometric Turbidity Unit; ND, not 

determined; --, no data]

Constituent or property Footnote

Analytical 

method 

number

Field or

laboratory 

reporting 

level

Study 

reporting 

level for data 

summary and 

analysis

CAS RN Typical use or source
68 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Table 11. Statistical summaries of analytical results for detected compounds in laboratory method-blank samples.

[Bold text indicates suspected endocrine-disrupting compound (EDC). μg/L, micrograms per liter; ND, not determined; --, not available]

Compound Footnote

Analytical 

method 

number

Number of 

methodblank 

samples

Number of 

methodblank 

samples

with 

detections

Minimum 

detected 

concentration

(μg/L)

Median

detected 

concentration

(μg/L)

Maximum 

detected 

concentration

(μg/L)

Study 

reporting 

level for data 

summary and 

analysis

(μg/L)

Human pharmaceutical compounds (HPCs)

Acetaminophen, dissolved 3 1 7 1 0.0040 0.0040 0.0040 ND

Caffeine, whole water 1 3 5 1 .0020 .0020 .0020 .12

Human and veterinary antibiotic compounds (HVACs)

Amoxicilin, dissolved 3, 4 2 20 1 -- 0.03 -- 0.05

Anhd-Cl-tetracycline, 

dissolved

3, 4 2 20 2 -- .21 -- .3

Anhydrotetracycline, 

dissolved

3, 4 2 20 6 -- .09 -- .15

Chlorotetracycline, dissolved 3, 4 2 20 5 -- .03 -- .05

Ciprofloxacin, dissolved 1, 4 2 20 3 -- .02 -- .036

Demeclocycline, dissolved 3, 4 2 20 8 -- .04 -- .08

Doxycycline, dissolved 3, 4 2 20 10 -- .03 -- .05

Erythromycin-H2O, 

dissolved

1, 4 2 20 9 -- .02 -- .046

Minocycline, dissolved 3, 4 2 20 4 -- .14 -- .25

Norfloxacin, dissolved 1, 4 2 20 1 -- .01 -- .02

Ofloxacin, dissolved 1, 4 2 20 4 -- .02 -- .03

Oxytetracycline, dissolved 3, 4 2 20 2 -- .08 -- .15

Sarafloxacin, dissolved 3, 4 2 20 1 -- .02 -- .03

Tetracycline, dissolved 1, 4 2 20 9 -- .03 -- .064

Trimethoprim, dissolved 1, 4 2 20 1 -- -- -- .02

Household, industrial, and minor agricultural-use compounds (HIACs)

4-tert-octylphenol, whole

water

3 3 5 5 0.024 0.048 0.079 0.26

7-acetyl-1,1,3,4,4,6-

hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

1 3 5 1 .0021 .0021 .0021 .048

Acetophenone, whole water 2 3 5 5 .022 .054 .11 .08

Benzophenone, whole water 1 3 5 1 .0074 .0074 .0074 .015

Bis(2-ethylhexyl) phthalate, 

whole water

1 3 3 3 .16 .59 .63 ND

Camphor, whole water 1 3 5 1 .020 .020 .020 .07
Supplemental Information 69

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

N,N-diethyl-meta-toluamide 

(DEET), whole water

1 3 5 1 0.0040 0.0040 0.0040 0.08

Diethyl phthalate, whole 

water

1 3 3 3 .045 .066 .33 .55

Nonylphenol diethoxylate 

(NP2EO), whole water

2 3 5 1 1.4 1.4 1.4 .55

Nonylphenol 

monoethoxylate 

(NP1EO), whole water

2 3 3 1 .72 .72 .72 .39

Octylphenol diethoxylate 

(OP2EO), whole water

1 3 5 1 .072 .072 .072 .14

Octylphenol 

monoethoxylate 

(OP1EO), whole water

3 3 5 2 .31 .32 .32 1

Methyl salicylate, whole 

water

3 3 5 1 .0051 .0051 .0051 .5

Phenol, whole water 3 3 5 3 .018 .033 .13 .94

Triphenyl phosphate, whole 

water

1 3 5 2 .0024 .0062 .0099 .015

Tri(2-

butoxyethyl)phosphate, 

whole water

1 3 5 1 .10 .10 .10 .13

Tri(dichloroisopropyl)

phosphate, whole water

1 3 5 1 .0080 .0080 .0080 .047

Polyaromatic hydrocarbons (PAHs)

1-methylnaphthalene, whole 

water

3 3 5 3 0.0029 0.0041 0.0082 0.5

2,6-dimethylnaphthalene, 

whole water

3 3 5 1 .0021 .0021 .0021 .5

2-methylnaphthalene, whole 

water

3 3 5 3 .0044 .0045 .0079 .5

Fluoranthene, whole water 3 3 5 1 .0017 .0017 .0017 .15

Isopropylbenzene (cumene), 

whole water

3 3 5 1 .0012 .0012 .0012 ND

Naphthalene, whole water 1 3 5 2 .0050 .0050 .0050 .01

Phenanthrene, whole water 3 3 5 1 .0032 .0032 .0032 .1

Pyrene, whole water 3 3 5 1 .0006 .0006 .0006 .04

Table 11. Statistical summaries of analytical results for detected compounds in laboratory method-blank samples.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). μg/L, micrograms per liter; ND, not determined; --, not available]

Compound Footnote

Analytical 

method 

number

Number of 

methodblank 

samples

Number of 

methodblank 

samples

with 

detections

Minimum 

detected 

concentration

(μg/L)

Median

detected 

concentration

(μg/L)

Maximum 

detected 

concentration

(μg/L)

Study 

reporting 

level for data 

summary and 

analysis

(μg/L)
70 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Sterol compounds (SCs)

3-beta-coprostanol, whole 

water

1 3 5 1 0.19 0.19 0.19 0.26

Cholesterol, whole water 1 3 5 1 .21 .21 .21 .64

1

Compound detected in one or more method-blank samples but at concentrations generally substantially less than study reporting level.

2

Compound detected infrequently in method-blank samples; compound was not detected in environmental samples associated with method-blank samples 

with detections, or compound was detected in method-blank samples at concentrations substantially less than detected concentrations in environmental samples 

associated with the method-blank samples with detections.

3

Compound detected in method-blank samples but not detected in any environmental samples at concentrations greater than study reporting level or compound excluded from analyses based on unacceptable results for laboratory-reagent spike or matrix-spike samples.

4

Raw data for laboratory method blank samples for analytical method 2 were not available; the laboratory only reported median concentrations for laboratory 

method blank samples.

Table 11. Statistical summaries of analytical results for detected compounds in laboratory method-blank samples.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). μg/L, micrograms per liter; ND, not determined; --, not available]

Compound Footnote

Analytical 

method 

number

Number of 

methodblank 

samples

Number of 

methodblank 

samples

with 

detections

Minimum 

detected 

concentration

(μg/L)

Median

detected 

concentration

(μg/L)

Maximum 

detected 

concentration

(μg/L)

Study 

reporting 

level for data 

summary and 

analysis

(μg/L)
Supplemental Information 71

Table 12. Statistical summaries of analytical results for laboratory reagent-spike samples.

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Analytical 

method 

number

Number of 

reagentspike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery 

RSD

Human pharmaceutical compounds (HPCs)

1,7-dimethylxanthine, dissolved 1 1 7 78 98 150 24

Acetaminophen, dissolved 1 1 7 76 85 120 18

Caffeine, dissolved 1 1 7 73 87 120 19

Caffeine, whole water 1 3 5 80 90 95 9

Carbamazepine, dissolved 1 1 7 58 93 110 21

Cimetidine, dissolved 2 1 7 6 41 53 45

Codeine, dissolved 1 1 7 59 91 110 20

Cotinine, dissolved 1 1 7 60 89 110 27

Cotinine, whole water 1 3 5 39 64 83 26

Dehydronifedipine, dissolved 1 1 7 67 95 120 19

Diltiazem, dissolved 1 1 7 34 61 69 25

Diphenhydramine, dissolved 1 1 7 40 65 80 24

Fluoxetine, dissolved 1 1 7 26 40 52 19

Furosemide, dissolved 2 1 7 0 0 0 0

Gemfibrozil, dissolved 1 1 7 30 57 63 20

Ibuprofen, dissolved 2 1 7 14 32 110 77

Metformin, dissolved 2 1 7 0 0 0 0

Miconazole, dissolved 2 1 7 5 12 21 42

Ranitidine, dissolved 1 1 7 34 57 66 22

Salbutamol, dissolved 1 1 7 36 69 99 30

Thiabendazole, dissolved 2 1 7 16 20 86 73

Warfarin, dissolved 1 1 7 61 77 120 22

Human and veterinary antibiotic compounds (HVACs)

Azithromycin, dissolved 2 1 7 0 4 13 99

Erythromycin, dissolved 2 1 7 1 6 15 86

Sulfamethoxazole, dissolved 1 1 7 42 94 100 30

Trimethoprim, dissolved 1 1 7 46 65 79 17

Major agricultural herbicides (MAHs)

Atrazine, whole water 1 3 3 120 130 140 10

Metolachlor, whole water 1 3 5 75 85 100 14

Prometon, whole water 1 3 5 85 100 120 14
72 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Household, industrial, and minor agricultural-use compounds (HIACs)

1,4-dichlorobenzene, whole water 1 3 5 34 35 44 14

2,2’,4,4’-tetrabromodiphenyl ether, whole 

water

1 3 3 75 110 130 27

3,4-dichlorophenyl isocyanate, whole water 2 3 3 40 150 150 56

3-methyl-1H-indole (skatol), whole water 1 3 5 75 85 90 7

3-tert-butyl-4-hydroxy anisole (BHA),

whole water

2 3 5 4 14 31 74

4-cumylphenol, whole water 1 3 5 85 85 95 6

4-normal-octylphenol, whole water 1 3 5 80 95 110 12

4-tert-octylphenol, whole water 1 3 5 80 90 95 6

5-methyl-1H-benzotriazole, whole water 1 3 5 100 120 200 32

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene (AHTN), whole 

water

1 3 5 80 80 90 5

Acetophenone, whole water 1 3 5 65 90 110 18

Anthraquinone, whole water 1 3 5 75 85 130 24

Benzophenone, whole water 1 3 5 75 85 90 7

Bis(2-ethylhexyl) phthalate, whole water 1 3 3 95 110 110 8

Bisphenol-A, whole water 1 3 5 70 85 95 11

Bromacil, whole water 1 3 5 76 88 96 9

Camphor, whole water 1 3 5 70 90 95 12

Carbaryl, whole water 2 3 5 25 35 80 49

Chlorpyrifos, whole water 1 3 5 75 75 80 4

N,N-diethyl-meta-toluamide (DEET), whole 

water

1 3 5 80 95 95 7

Diazinon, whole water 1 3 5 80 85 90 6

Dichlorvos, whole water 1 3 5 60 80 100 18

Diethyl phthalate, whole water 1 3 3 85 90 90 3

D-Limonene, whole water 2 3 5 9 14 21 31

1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-

hexamethyl cyclopenta-g-2-benzopyran 

(HHCB), whole water

1 3 5 85 95 100 8

Indole, whole water 1 3 5 70 80 85 8

Isoborneol, whole water 1 3 5 65 85 90 12

Isophorone, whole water 1 3 5 70 85 100 15

Isoquinoline, whole water 1 3 5 60 65 80 13

Table 12. Statistical summaries of analytical results for laboratory reagent-spike samples.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Analytical 

method 

number

Number of 

reagentspike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery 

RSD
Supplemental Information 73

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

Menthol, whole water 1 3 5 60 80 85 13

Metalaxyl, whole water 1 3 5 85 90 95 5

Methyl salicylate, whole water 1 3 5 65 80 90 11

Nonylphenol diethoxylate (NP2EO), 

whole water

1 3 5 88 88 110 12

Nonylphenol monoethoxylate (NP1EO),

whole water

1 3 3 94 100 120 12

Octylphenol diethoxylate (OP2EO), 

whole water

1 3 5 71 79 93 12

Octylphenol monoethoxylate (OP1EO), 

whole water

1 3 5 68 79 79 7

para-cresol, whole water 1 3 5 70 85 100 15

para-nonylphenol (NP), whole water 1 3 5 75 94 110 14

Pentachlorophenol, whole water 1 3 5 43 53 55 12

Phenol, whole water 1 3 5 70 75 95 13

Tetrachloroethylene, whole water 2 3 5 5 13 16 38

Tributyl phosphate, whole water 1 3 5 80 90 100 8

Triclosan, whole water 1 3 5 70 75 100 16

Triethyl citrate (ethyl citrate), whole water 1 3 5 80 90 110 14

Triphenyl phosphate, whole water 1 3 5 80 95 100 10

Tri(2-butoxyethyl)phosphate, whole water 1 3 5 85 100 100 8

Tri(2-chloroethyl)phosphate, whole water 1 3 5 80 90 100 10

Tri(dichloroisopropyl)phosphate, whole 

water

1 3 5 90 105 140 21

Polyaromatic hydrocarbons (PAHs)

1-methylnaphthalene, whole water 1 3 5 50 60 65 10

2,6-dimethylnaphthalene, whole water 1 3 5 44 55 60 13

2-methylnaphthalene, whole water 1 3 5 50 60 60 8

Anthracene, whole water 1 3 5 75 90 95 10

Benzo[a]pyrene, whole water 1 3 5 75 80 85 5

Carbazole, whole water 1 3 5 75 95 100 12

Fluoranthene, whole water 1 3 5 80 90 100 8

Isopropylbenzene (cumene), whole water 2 3 5 14 20 22 19

Naphthalene, whole water 1 3 5 50 55 60 7

Phenanthrene, whole water 1 3 5 65 85 85 11

Pyrene, whole water 1 3 5 65 75 85 10

Table 12. Statistical summaries of analytical results for laboratory reagent-spike samples.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Analytical 

method 

number

Number of 

reagentspike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery 

RSD
74 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Sterol compounds (SCs)

3-beta-coprostanol, whole water 1 3 5 78 85 95 8

beta-sitosterol, whole water 1 3 5 60 78 95 16

beta-stigmastanol, whole water 1 3 5 59 80 99 18

Cholesterol, whole water 1 3 5 71 85 88 9

1Median percent recovery for reagent-spike samples within acceptable range (30-120 percent), and percent recovery RSD acceptable (less than 40 percent).

2

Median percent recovery for reagent-spike samples outside of acceptable range (30-120 percent) or percent recovery RSD unacceptable (greater than 

40 percent); compound excluded from analyses and discussion related to occurrence of emerging contaminants in wastewater effluents and the Big Sioux River.

Table 13. Statistical summaries of analytical results for laboratory surrogate samples.

[RSD, relative standard deviation]

Compound Footnote

Analytical 

method 

number

Number of 

spiked 

environmental 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery 

RSD

Bisphenol-A-d3 (surrogate) 1 3 30 48 100 160 30

Caffeine-c13 (surrogate) 1 3 30 46 87 110 18

Decafluorobiphenyl (surrogate) 1 3 30 30 59 82 22

Ethyl-nicontinate-d4 (surrogate) 1 1 30 72 94 160 21

Fluoranthene-d10 (surrogate) 1 3 30 46 87 130 24

1

Median percent recovery for reagent-spike samples within acceptable range (30 to 120 percent), and percent recovery RSD acceptable (less than 40 percent).

Table 12. Statistical summaries of analytical results for laboratory reagent-spike samples.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Analytical 

method 

number

Number of 

reagentspike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery 

RSD
Table 14. Statistical summaries of analytical results for detected compounds in field equipment-blank samples.

[Bold text indicates suspected endocrine-disrupting compound (EDC). μg/L, micrograms per liter; e, estimated; ND, not determined]

Compound

Analytical 

method 

number

Number of 

field 

equipmentblank samples

Number of 

field 

equipmentblank samples 

with 

detections

Minimum 

detected 

concentration

(μg/L)

Median

detected 

concentration

(μg/L)

Maximum 

concentration

(μg/L)

Study

reporting

level

(μg/L)

Human pharmaceutical compounds (HPCs)

Acetaminophen, dissolved 1 9 3 e0.0058 e0.0091 e0.022 ND

Caffeine, dissolved 1 9 2 e.011 e.013 e.015 .022

Diphenhydramine, dissolved 1 9 1 e.0004 e.0004 e.0004 ND

Fluoxetine, dissolved 1 9 1 .018 .018 .018 ND

Human and veterinary antibiotic compounds (HVACs)

Ciprofloxacin, dissolved 2 9 1 0.011 0.011 0.011 0.036

Clinafloxacin, dissolved 2 9 1 .0060 .0060 .0060 .01

Erythromycin-H2O, dissolved 2 9 1 .019 .019 .019 .025

Sulfamethoxazole, dissolved 2 9 1 .017 .017 .017 .02

Household, industrial, and minor agricultural-use compounds (HIACs)

1,4-dichlorobenzene, whole water 3 8 1 e0.38 e0.38 e0.38 ND

4-tert-octylphenol, whole water 3 8 1 e.13 e.13 e.13 .26

Acetophenone, whole water 3 8 1 e.057 e.057 e.057 .08

Anthraquinone, whole water 3 8 2 e.060 e.27 e.48 .96

Benzophenone, whole water 3 8 1 e.017 e.017 e.017 .025

Bis(2-ethylhexyl) phthalate, whole 

water

3 8 1 e1.3 e1.3 e1.3 ND

N,N-diethyl-meta-toluamide 

(DEET), whole water

3 8 1 e.043 e.043 e.043 .08

Isophorone, whole water 3 8 1 e.024 e.024 e.024 .047

Isoquinoline, whole water 3 8 1 e.090 e.090 e.090 .5

Phenol, whole water 3 8 2 e.45 e.46 e.47 .94

Polyaromatic hydrocarbons (PAHs)

Anthracene, whole water 3 8 1 e0.030 e0.030 e0.030 0.5

Benzo[a]pyrene, whole water 3 8 1 e.056 e.056 e.056 .5

Carbazole, whole water 3 8 1 e.21 e.21 e.21 .22

Fluoranthene, whole water 3 8 1 e.030 e.030 e.030 .15

Phenanthrene, whole water 3 8 2 e.017 e.048 e.079 .1

Pyrene, whole water 3 8 2 e.011 e.024 e.037 .04

Sterol compounds (SCs)

Cholesterol, whole water 3 8 1 e0.56 e0.56 e0.56 0.64

Supplemental Information 75
76 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Table 15. Statistical summaries for field replicate samples for organic wastewater compounds (OWCs) detected in any sample for any 

primary/replicate sample pair.

[Bold text indicates suspected endocrine-disrupting compound (EDC)]

Compound Footnote

Number of 

field primary/

replicate 

sample pairs

Number of field primary/

replicate sample pairs in

which compound was detected

at concentration greater than

study reporting level

Summary statistics for relative percent 

differences for primary/replicate 

sample pairs in which the compound

was detected in both samples

In either sample In both samples Minimum Median Maximum

Human pharmaceutical compounds (HPCs)

Caffeine, dissolved 2 9 5 4 4.1 8.3 53

Caffeine, whole water 1 9 2 2 8.2 23 37

Carbamazepine, dissolved 1 9 2 2 5.9 7.3 8.8

Codeine, dissolved 1 9 1 1 16 16 16

Cotinine, dissolved 1 9 7 7 0 7.8 63

Diltiazem, dissolved 1 9 1 1 12 12 12

Diphenhydramine, dissolved 1 9 2 2 5.7 7.1 8.5

Metformin, dissolved 1 9 1 1 5.3 5.3 5.3

Salbutamol, dissolved 1 9 1 1 40 40 40

Human and veterinary antibiotic compounds (HVACs)

Ciprofloxacin, dissolved 1 13 1 1 12 12 12

Erythromycin, dissolved 1 13 3 3 1.1 7.5 13

Erythromycin-H2O, dissolved 1 13 6 6 2.4 9.5 19

Ofloxacin, dissolved 1 13 2 2 22 26 30

Sulfamethoxazole, dissolved 1 9 1 1 6.5 6.5 6.5

Sulfamethoxazole, dissolved 1 13 6 6 13 26 121

Trimethoprim, dissolved 1 10 3 3 3.7 8.0 21

Trimethoprim, dissolved 1 13 3 3 3.6 13 22

Tylosin, dissolved 1 13 1 1 39 39 39

Major agricultural herbicides (MAHs)

Atrazine, whole water 1 10 7 7 2.0 9.5 17

Metolachlor, whole water 1 10 5 5 1.6 7.2 14

Prometon, whole water 2 10 3 2 1.7 5.6 9.5

Household, industrial, and minor agricultural-use compounds (HIACs)

1,4-dichlorobenzene, whole water 1 10 3 3 3.2 17 79

3,4-dichlorophenyl isocyanate, 

whole water

4 9 3 3 23 46 86

4-tert-octylphenol, whole water 1 10 2 2 5.4 12 19

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

2 10 4 3 5.4 11 39
Supplemental Information 77

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

Acetophenone, whole water 3 10 2 2 20 50 81

Anthraquinone, whole water 1 10 1 1 18 18 18

Benzophenone, whole water 1 10 1 1 37 37 37

N,N-diethyl-meta-toluamide 

(DEET), whole water

1 10 4 4 0 19 40

1,3,4,6,7,8-hexahydro4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran 

(HHCB), whole water

1 10 3 3 15 21 50

Indole, whole water 1 10 2 2 26 29 32

Nonylphenol diethoxylate 

(NP2EO), whole water

1 10 2 2 11 14 16

Nonylphenol monoethoxylate 

(NP1EO), whole water

3 10 1 1 44 44 44

Octylphenol diethoxylate 

(OP2EO), whole water

1 10 1 1 13 13 13

para-nonylphenol (NP), whole 

water

1 10 1 1 12 12 12

Tributyl phosphate, whole water 1 10 5 5 0 5.2 17

Triclosan, whole water 1 10 1 1 14 14 14

Triethyl citrate (ethyl citrate), 

whole water

1 10 3 3 1.2 11 26

Triphenyl phosphate, whole water 1 10 2 2 5.9 16 25

Tri(2-butoxyethyl)phosphate, 

whole water

2 10 3 2 4.5 12 19

Tri(2-chloroethyl)phosphate, 

whole water

1 10 4 4 0 .85 30

Tri(dichloroisopropyl)phosphate, 

whole water

1 10 3 3 7.4 22 38

Polyaromatic hydrocarbons (PAHs)

1-methylnaphthalene, whole water 1 10 1 1 9.5 9.5 9.5

2-methylnaphthalene, whole water 1 10 1 1 23 23 23

Phenanthrene, whole water 1 10 2 2 4.3 31 58

Pyrene, whole water 3 10 1 1 68 68 68

Table 15. Statistical summaries for field replicate samples for organic wastewater compounds (OWCs) detected in any sample for any 

primary/replicate sample pair.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC)]

Compound Footnote

Number of 

field primary/

replicate 

sample pairs

Number of field primary/

replicate sample pairs in

which compound was detected

at concentration greater than

study reporting level

Summary statistics for relative percent 

differences for primary/replicate 

sample pairs in which the compound

was detected in both samples

In either sample In both samples Minimum Median Maximum
78 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Sterol compounds (SCs)

3-beta-coprostanol, whole water 1 10 4 4 1.0 20 33

beta-sitosterol, whole water 2 10 2 1 4.1 4.1 4.1

Cholesterol, whole water 2 10 9 7 1.9 29 49

1

When compound was detected at concentrations above the study reporting level in either sample of a primary/replicate sample pair, compound was always 

detected in both samples; median relative percent difference acceptable (less than 40 percent); field replicate results judged to be acceptable.

2Infrequently, compound was detected at a concentration greater than the study reporting level in either the primary or replicate sample, but not both; median 

relative percent difference acceptable (less than 40 percent); all other quality-assurance/quality control results for compound were acceptable; field replicate 

results judged to be acceptable.

3Compound was detected at a concentration above the study reporting level in both samples of a single primary/replicate sample pair; relative percent 

difference exceeded 40 percent; all other quality-assurance/quality-control results for compound were acceptable; field replicate results judged to be acceptable.

4

Compound was detected at a concentration above the study reporting level in multiple primary/replicate sample pairs; median relative percent difference 

exceeded 40 percent; replicate results unacceptable; however, compound was excluded from analyses and discussion related to occurrence of emerging 

contaminants in Big Sioux River and wastewater effluents based on unacceptable laboratory reagent-spike and/or matrix-spike sample results.

Table 15. Statistical summaries for field replicate samples for organic wastewater compounds (OWCs) detected in any sample for any 

primary/replicate sample pair.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC)]

Compound Footnote

Number of 

field primary/

replicate 

sample pairs

Number of field primary/

replicate sample pairs in

which compound was detected

at concentration greater than

study reporting level

Summary statistics for relative percent 

differences for primary/replicate 

sample pairs in which the compound

was detected in both samples

In either sample In both samples Minimum Median Maximum
Supplemental Information 79

Table 16. Statistical summaries for environmental matrix spikes for wastewater effluent and Big Sioux River samples collected in the 

Sioux Falls area during 2002–2004.

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Number of 

matrix spike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery

RSD

Human pharmaceutical compounds (HPCs)

1,7-dimethylxanthine, dissolved 1 10 42 60 71 16

Acetaminophen, dissolved 3 10 -9.3 40 52 46

Caffeine (method 1), dissolved 1 10 29 33 45 15

Caffeine (method 3), whole water 1 3 89 94 100 7.7

Carbamazepine, dissolved 3 10 4.9 19 33 48

Cimetidine, dissolved 3 10 8.3 23 32 44

Codeine, dissolved 3 10 38 70 140 49

Cotinine (method 1), dissolved 1 10 31 41 56 23

Cotinine (method 3), whole water 1 3 48 63 73 21

Dehydronifedipine, dissolved 1 10 39 46 81 27

Diltiazem, dissolved 3 10 5.9 12 30 60

Diphenhydramine, dissolved 3 10 8.2 11 29 55

Fluoxetine, dissolved 3 10 0 .22 20 250

Furosemide, dissolved 3 10 0 8.0 49 120

Gemfibrozil, dissolved 3 10 0 0 17 210

Ibuprofen, dissolved 3 10 0 0 35 320

Metformin, dissolved 3 10 0 1.5 9.3 120

Miconazole, dissolved 3 10 0 0 30 320

Ranitidine, dissolved 3 10 0 11 42 78

Salbutamol, dissolved 1 10 33 51 64 24

Thiabendazole, dissolved 3 10 0 7.7 22 83

Warfarin, dissolved 3 10 0 29 46 54

Human and veterinary antibiotic compounds (HVACs)

Azithromycin, dissolved 3 10 0 3.3 16 110

Erythromycin (method 1), dissolved 3 10 0 9.6 46 120

Sulfamethoxazole (method 1), dissolved 3 10 0 11 42 92

Trimethoprim (method 1), dissolved 3 9 10 18 32 40

Major agricultural herbicides (MAHs)

Atrazine, whole water 1 3 110 120 160 19

Metolachlor, whole water 1 3 53 69 82 21

Prometon, whole water 1 3 80 100 110 15
80 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Household, industrial, and minor agricultural-use compounds (HIACs)

1,4-dichlorobenzene, whole water 3 3 23 23 45 42

2,2’,4,4’-tetrabromodiphenyl ether, 

whole water

1 3 58 72 72 12

3,4-dichlorophenyl isocyanate, whole water 3 3 39 110 230 78

3-methyl-1H-indole (skatol), whole water 1 3 62 81 85 16

3-tert-butyl-4-hydroxy anisole (BHA), whole 

water

3 3 3.0 7.2 63 140

4-cumylphenol, whole water 1 3 71 98 100 19

4-normal-octylphenol, whole water 1 3 84 85 98 8.9

4-tert-octylphenol, whole water 1 3 71 94 94 15

5-methyl-1H-benzotriazole, whole water 2 3 130 140 200 23

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene (AHTN), whole 

water

1 3 58 71 72 12

Acetophenone, whole water 1 3 67 81 98 20

Anthraquinone, whole water 1 3 80 81 90 6.4

Benzophenone, whole water 1 3 67 85 90 15

Bis(2-ethylhexyl) phthalate, whole water 3 3 89 94 220 51

Bisphenol-A, whole water 1 3 93 120 130 17

Bromacil, whole water 1 3 78 110 110 17

Bromoform, whole water 1 3 36 45 67 32

Camphor, whole water 1 3 62 81 94 20

Carbaryl, whole water 3 3 140 150 170 10

Chlorpyrifos, whole water 1 3 44 63 72 23

N,N-diethyl-meta-toluamide (DEET), whole 

water

1 3 67 92 99 20

Diazinon, whole water 1 3 62 81 90 18

Dichlorvos, whole water 1 3 75 94 94 12

Diethyl phthalate, whole water 1 3 71 90 94 15

D-Limonene, whole water 3 3 7.1 7.6 24 75

1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran (HHCB), whole 

water

1 3 53 79 81 22

Indole, whole water 1 3 58 63 72 11

Table 16. Statistical summaries for environmental matrix spikes for wastewater effluent and Big Sioux River samples collected in the 

Sioux Falls area during 2002–2004.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Number of 

matrix spike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery

RSD
Supplemental Information 81

Household, industrial, and minor agricultural-use compounds (HIACs)—Continued

Isoborneol, whole water 1 3 62 81 90 18

Isophorone, whole water 1 3 67 90 94 18

Isopropylbenzene (cumene), whole water 3 3 10 10 26 57

Isoquinoline, whole water 1 3 62 76 81 13

Menthol, whole water 1 3 67 81 85 13

Metalaxyl, whole water 1 3 62 94 100 25

Methyl salicylate, whole water 1 3 58 76 85 19

Nonylphenol diethoxylate (NP2EO), whole 

water

1 3 80 98 100 13

Nonylphenol monoethoxylate (NP1EO), 

whole water

1 3 89 100 110 10

Octylphenol diethoxylate (OP2EO), whole 

water

1 3 72 84 91 12

Octylphenol monoethoxylate (OP1EO), 

whole water

1 3 54 69 77 18

para-cresol, whole water 1 3 75 85 85 6.9

para-nonylphenol (NP), whole water 1 3 76 85 92 9.3

Pentachlorophenol, whole water 1 3 83 85 85 1.7

Phenol, whole water 1 3 58 72 90 22

Tetrachloroethylene, whole water 3 3 5.8 6.3 17.5 67

Tributyl phosphate, whole water 1 3 62 81 94 20

Triclosan, whole water 1 3 110 110 120 4.9

Triethyl citrate (ethyl citrate), whole water 1 3 80 93 99 11

Triphenyl phosphate, whole water 1 3 71 90 110 20

Tri(2-butoxyethyl)phosphate, whole water 1 3 80 88 90 6.1

Tri(2-chloroethyl)phosphate, whole water 1 3 80 100 100 14

Tri(dichloroisopropyl)phosphate, whole water 1 3 98 110 110 7.0

Polyaromatic hydrocarbons (PAHs)

1-methylnaphthalene, whole water 1 3 44 49 72 26

2,6-dimethylnaphthalene, whole water 1 3 43 44 72 31

2-methylnaphthalene, whole water 1 3 44 45 76 33

Anthracene, whole water 1 3 75 76 98 16

Benzo[a]pyrene, whole water 1 3 53 63 67 12

Table 16. Statistical summaries for environmental matrix spikes for wastewater effluent and Big Sioux River samples collected in the 

Sioux Falls area during 2002–2004.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Number of 

matrix spike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery

RSD
82 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

Polyaromatic hydrocarbons (PAHs)—Continued

Carbazole, whole water 1 3 84 99 110 14

Fluoranthene, whole water 1 3 71 75 95 16

Naphthalene, whole water 1 3 40 44 67 29

Phenanthrene, whole water 1 3 70 71 87 13

Pyrene, whole water 1 3 58 62 82 19

Sterol compounds (SCs)

3-beta-coprostanol, whole water 1 3 73 100 100 20

beta-sitosterol, whole water 2 3 140 160 210 21

beta-stigmastanol, whole water 3 3 100 200 240 38

Cholesterol, whole water 1 3 82 90 120 21

1Median spike recovery within acceptable range (30-120 percent) and median spike recovery RSD acceptable (less than 40 percent); matrix-spike results 

judged to be acceptable.

2

Median spike recovery greater than 120 percent, but median spike recovery RSD acceptable (less than 40 percent) and all other quality-assurance/qualitycontrol results acceptable; matrix-spike results judged to be acceptable.

3Median spike recovery outside of acceptable range (30 to 120 percent) and/or median spike recovery RSD unacceptable (greater than 40 percent).

Table 16. Statistical summaries for environmental matrix spikes for wastewater effluent and Big Sioux River samples collected in the 

Sioux Falls area during 2002–2004.—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). RSD, relative standard deviation]

Compound Footnote

Number of 

matrix spike 

samples

Minimum 

percent 

recovery

Median

percent 

recovery

Maximum 

percent 

recovery

Percent 

recovery

RSD
Table 17. Results for field-measured properties and constituents and auxiliary constituents.

[LE, analytical results unavailable due to laboratory error. ft, feet; ft3/s, cubic feet per second; NTU, Nephelometric Turbidity Units; mm Hg, millimeter of mercury; mg/L, millig

10 logarithm of hydrogen ion activity, in moles per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; col/100 mL, colonies per 100 milliliters

--, no data collected]

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

Bi

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004 08-20-2003 06-15-2004 08-20Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730 0915 1825 14Property or constituentDischarge, instantaneous (ft3/s) .45 21.8 .46 8.8 e4.9 e6.1 5.89 16.5 6.88 35.5 14Turbidity (NTU) -- 20.4 -- 11.8 -- 5.0 -- 13.6 -- 33.2 -Barometric pressure (mm Hg) 717 721 718 719 719 724 719 719 716 717 718 Dissolved oxygen (mg/L) 7.5 4.5 12.1 4.9 9.4 10.1 6.3 8.4 6.3 7.5 14pH (standard units) 8.3 7.8 7.9 7.8 7.7 7.4 7.7 7.7 8.6 8.0 8Specific conductance (μS/cm) 616 780 822 786 1,223 1,280 1,055 996 1,134 908 852 Air temperature (°C) 26.5 18.5 30.5 22.0 30.5 15.6 21.0 26.0 23.5 26.5 34Water temperature (°C) 25.0 19.8 24.1 20.9 20.1 15.6 20.1 19.5 22.2 21.8 30Nitrite plus nitrate nitrogen 

(mg/L)

<.060 <.060 <.060 .224 13.4 18.9 7.72 5.62 6.00 2.13 <

Total coliform concentration, 

most probable number

(col/100 mL)

1,100 300 3,000 1,700 8,000 1,300 50,000 8,000 8,000 1,300 3,000 

Fecal coliform concentration, 

membrane filter (col/100 mL)

60 280 450 340 30 40 1300 250 1,600 200 1,300 
Table 17. Results for field-measured properties and constituents and auxiliary constituents.—Continued

[LE, analytical results unavailable due to laboratory error. ft, feet; ft3/s, cubic feet per second; NTU, Nephelometric Turbidity Units; mm Hg, millimeter of mercury; mg/L, millig

10 logarithm of hydrogen ion activity, in moles per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; col/100 mL, colonies per 100 milliliters

--, no data collected]

Station identification and name (site label)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

441421096491200

Big Sioux River above 

wastewater effluent, 

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater

effluent near

Brookings, SD

(BK-WWE)

44131609648

Big Sioux River 

wastewater ef

near Brooking

(BK-DS1

Date of sample collection 08-21-2003 10-21-2003 06-16-2004 08-21-2003 10-22-2003 06-16-2004 08-21-2003 06-17-2004 08-22-2003 06-17-2004 08-22-2003 06-Time of sample collection 0900 1240 1435 1100 0935 1615 1230 1140 0915 0950 1015 Property or constituentDischarge, instantaneous (ft3/s) -- e.6 <.2 11.4 9.7 130 3.18 129 e1.7 e5.6 9.89 2Turbidity (NTU) -- 15.0 16.6 -- 36.0 -- -- 34.4 -- 3.8 -- Barometric pressure (mm Hg) 724 723 725 726 726 728 726 729 729 729 729 7Dissolved oxygen (mg/L) .3 2.8 .8 7.3 9.6 8.4 10.1 8.4 8.9 10.1 7.1 pH (standard units) 9.1 8.0 7.9 8.4 7.8 8.1 8.6 7.9 7.3 7.5 8.2 Specific conductance (μS/cm) 6,890 6,600 3,650 885 1,240 843 878 861 1,630 1,420 1,066 9Air temperature (°C) 22.0 19.0 19.0 20.0 6.5 19.0 28.0 20.5 23.0 20.0 23.0 Water temperature (°C) 23.0 12.2 18.9 23.6 10.3 20.2 25.5 18.9 19.7 15.4 20.0 Nitrite plus nitrate nitrogen 

(mg/L)

<.060 .077 <.060 <.060 <.060 .181 <.060 .233 22.9 17.2 3.07 

Total coliform concentration, 

most probable number

(col/100 mL)

90,000 5,000 300 3,000 500 1,300 2,300 1,300 LE 80 LE 

Fecal coliform concentration, 

membrane filter (col/100 mL)

2,600 360 <10 180 40 610 550 340 LE 10 LE 
Table 18. Analytical results for human pharmaceutical compounds (HPCs).

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. ND, not determined; UD, undetected, laboratory reporting level not determined; <, less than; e, estimated]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004

Time of sample collection 1045 1030 1200 1200 1305 0925

Compound

1,7-dimethylxanthine, 

dissolved

1 0.05 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144

Acetaminophen, dissolved 1 ND .129 e.0094 <.036 e.0031 <.036 <.036

Caffeine, dissolved 1 .022 <.016 <.016 <.016 <.016 e.0069 <.016

Caffeine, whole water 3 .12 <.5 <.5 <.5 <.5 <.5 <.5

Carbamazepine, dissolved 1 ND <.011 <.011 <.011 <.011 .091 .073

Cimetidine, dissolved 1 ND <.012 <.012 <.012 <.012 .033 .14

Codeine, dissolved 1 ND <.015 <.015 <.015 <.015 .036 .022

Cotinine, dissolved 1 .0008 e.0047 <.014 e.0027 <.014 .049 .017

Cotinine, whole water 3 .18 <1 <1 <1 <1 <1 <1

Dehydronifedipine, 

dissolved

1 .0035 <.015 <.015 <.015 <.015 e.0035 <.015

Diltiazem, dissolved 1 ND <.016 <.016 <.016 <.016 .030 .057

Diphenhydramine, dissolved 1 ND <.015 <.015 <.015 e.0085 .062 .084

Fluoxetine, dissolved 1 ND <.014 <.014 <.014 <.014 <.014 <.014

Furosemide, dissolved 1 ND <.039 <.039 <.039 <.039 <.039 <.039

Gemfibrozil, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013

Ibuprofen, dissolved 1 ND <.042 <.042 <.042 <.042 <.042 <.042

Metformin, dissolved 1 ND UD UD UD UD UD UD

Miconazole, dissolved 1 ND <.018 <.018 <.018 <.018 <.018 <.018

Ranitidine, dissolved 1 ND <.013 <.013 <.013 <.013 .038 .16

Salbutamol, dissolved 1 .0054 <.023 <.023 <.023 <.023 .034 .036

Thiabendazole, dissolved 1 ND <.011 <.011 <.011 <.011 <.011 <.011

Warfarin, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012

Supplemental Information 85
Table 18. Analytical results for human pharmaceutical compounds (HPCs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. ND, not detected, laboratory reporting level not determined; <, less than; e, estimated]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

Date of sample 

collection

08-19-2003 06-15-2004 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004

Time of sample 

collection

0930 1730 0915 1825 1400 1105 1145

Compound

1,7-dimethylxanthine, 

dissolved

1 0.05 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144

Acetaminophen, 

dissolved

1 ND e.002 e.014 e.011 e.0060 <.036 <.036 e.021

Caffeine, dissolved 1 .022 .087 <.016 e.0092 e.0095 <.016 <.016 .030

Caffeine, whole water 3 .12 e.24 <.5 <.5 <.5 <.5 e.011 <.5

Carbamazepine, 

dissolved

1 ND .023 e.0069 .078 <.011 <.011 .023 <.011

Cimetidine, dissolved 1 ND <.012 e.0054 .017 <.012 <.012 <.012 <.012

Codeine, dissolved 1 ND .015 <.015 .020 <.015 <.015 <.015 <.015

Cotinine, dissolved 1 .0008 .039 e.0066 .042 e.0051 .035 e.022 e.007

Cotinine, whole water 3 .18 <1 <1 <1 <1 <1 e.18 <1

Dehydronifedipine, 

dissolved

1 .0035 <.015 <.015 e.0039 <.015 <.015 <.015 <.015

Diltiazem, dissolved 1 ND <.016 e.010 <.016 e.0030 <.016 <.016 <.016

Diphenhydramine, 

dissolved

1 ND <.015 e.0027 <.015 e.0035 <.015 <.015 e.0013

Fluoxetine, dissolved 1 ND <.014 <.014 <.014 <.014 <.014 <.014 <.014

Furosemide, dissolved 1 ND <.039 <.039 <.039 <.039 <.039 <.039 <.039

Gemfibrozil, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013 <.013

Ibuprofen, dissolved 1 ND <.042 <.042 <.042 <.042 <.042 <.042 <.042

Metformin, dissolved 1 ND UD UD UD UD UD UD UD

Miconazole, dissolved 1 ND <.018 <.018 <.018 <.018 <.018 <.018 <.018

Ranitidine, dissolved 1 ND <.013 .020 <.013 <.013 <.013 <.013 <.013

Salbutamol, dissolved 1 .0054 e.0054 <.023 e.0090 <.023 <.023 <.023 <.023

Thiabendazole, 

dissolved

1 ND .011 <.011 <.011 <.011 <.011 <.011 <.011

Warfarin, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012 <.012

86 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 18. Analytical results for human pharmaceutical compounds (HPCs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. ND, not detected, laboratory reporting level not determined; <, less than; e, estimated]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewater wetland, 

near Volga, SD

(VL-DS1)

Date of sample 

collection

08-21-2003 10-21-2003 06-16-2004 08-21-2003 10-22-2003 06-16-2004

Time of sample 

collection

0900 1240 1435 1100 0935 1615

Compound

1,7-dimethylxanthine, 

dissolved

1 0.05 <0.144 <0.144 <0.144 <0.144 e0.049 <0.144

Acetaminophen, 

dissolved

1 ND <.036 <.036 .20 <.036 .058 <.036

Caffeine, dissolved 1 .022 <.016 <.016 .075 <.016 .073 <.016

Caffeine, whole water 3 .12 <.5 e.034 <.5 <.5 <.5 <.5

Carbamazepine, 

dissolved

1 ND .019 .019 <.011 .015 .021 <.011

Cimetidine, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012

Codeine, dissolved 1 ND <.015 <.015 <.015 <.015 <.015 <.015

Cotinine, dissolved 1 .0008 .049 e.0188 e.0089 .038 .024 e.003

Cotinine, whole water 3 .18 <1 <1 <1 <1 <1 <1

Dehydronifedipine, 

dissolved

1 .0035 <.015 <.015 <.015 <.015 <.015 <.015

Diltiazem, dissolved 1 ND <.016 <.016 <.016 <.016 <.016 <.016

Diphenhydramine, 

dissolved

1 ND <.015 <.015 <.015 <.015 <.015 e.0006

Fluoxetine, dissolved 1 ND <.014 <.014 <.014 <.014 <.014 <.014

Furosemide, dissolved 1 ND <.039 <.039 <.039 <.039 <.039 <.039

Gemfibrozil, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013

Ibuprofen, dissolved 1 ND <.042 <.042 <.042 <.042 <.042 <.042

Metformin, dissolved 1 ND UD UD UD UD UD UD

Miconazole, dissolved 1 ND <.018 <.018 <.018 <.018 <.018 <.018

Ranitidine, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013

Salbutamol, dissolved 1 .0054 <.023 <.023 <.023 <.023 <.023 <.023

Thiabendazole, dissolved 1 ND <.011 <.011 <.011 <.011 <.011 <.011

Warfarin, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012

Supplemental Information 87
Table 18. Analytical results for human pharmaceutical compounds (HPCs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. ND, not detected, laboratory reporting level not determined; <, less than; e, estimated]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

441421096491200

Big Sioux River above 

wastewater effluent, 

near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastewater

effluent near

Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent, 

near Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above 

Medary Creek, at 

Medary, SD

(BK-DS2)

Date of sample 

collection

08-21-2003 06-17-2004 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample 

collection

1230 1140 0915 0950 1015 1215 1140 1645

Compound

1,7-dimethylxanthine, 

dissolved

1 0.05 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144 <0.144

Acetaminophen, 

dissolved

1 ND e.014 <.036 <.036 <.036 <.036 .48 <.036 <.036

Caffeine, dissolved 1 .022 .029 <.016 <.016 <.016 <.016 .048 <.016 <.016

Caffeine, whole water 3 .12 <.5 e.13 <.5 <.5 <.5 <.5 <.5 <.5

Carbamazepine, 

dissolved

1 ND .013 <.011 .24 .18 .053 <.011 .075 <.011

Cimetidine, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012 <.012 <.012

Codeine, dissolved 1 ND <.015 <.015 e.0047 <.015 <.015 <.015 <.015 <.015

Cotinine, dissolved 1 .0008 .033 <.014 e.021 .022 .030 e.0023 .030 e.0011

Cotinine, whole water 3 .18 <1 <1 <1 <1 <1 <1 <1 <1

Dehydronifedipine, 

dissolved

1 .0035 <.015 <.015 e.0052 <.015 <.015 <.015 <.015 <.015

Diltiazem, dissolved 1 ND <.016 <.016 <.016 e.0004 <.016 <.016 <.016 <.016

Diphenhydramine, 

dissolved

1 ND <.015 <.015 .059 .068 <.015 <.015 <.015 <.015

Fluoxetine, dissolved 1 ND <.014 <.014 <.014 <.014 <.014 <.014 <.014 <.014

Furosemide, dissolved 1 ND <.039 <.039 <.039 <.039 <.039 <.039 <.039 <.039

Gemfibrozil, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013 <.013 <.013

Ibuprofen, dissolved 1 ND <.042 <.042 <.042 <.042 <.042 <.042 <.042 <.042

Metformin, dissolved 1 ND UD UD UD UD UD UD UD UD

Miconazole, dissolved 1 ND <.018 <.018 <.018 <.018 <.018 <.018 <.018 <.018

Ranitidine, dissolved 1 ND <.013 <.013 <.013 <.013 <.013 <.013 <.013 <.013

Salbutamol, dissolved 1 .0054 <.023 <.023 <.023 <.023 <.023 <.023 <.023 <.023

Thiabendazole, 

dissolved

1 ND <.011 <.011 <.011 <.011 <.011 <.011 <.011 <.011

Warfarin, dissolved 1 ND <.012 <.012 <.012 <.012 <.012 <.012 <.012 <.012

88 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 19. Analytical results for human and veterinary antibiotic compounds (HVACs).

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in analyses 

related to occurrence of organic wastewater compounds. Units are micrograms per liter. All compounds are dissolved. <, less than; e, estimated; ND, not determined]

Analytical

method

number

Study 

reporting

level

Station identification and name (site label)

06479500

Big Sioux River

at Watertown, SD

(WT-US1)

06479512

Big Sioux River at

Broadway, at Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004

Time of sample collection 1045 1030 1200 1200 1305 0925

Compound

Amoxicilin 2 0.05 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Ampicillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Anhd-Cl-tetracycline 2 .3 <.01 <.01 <.01 <.01 <.01 <.01

Anhydrotetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01

Azithromycin 1 ND <.004 <.004 <.004 <.004 <.004 <.004

Cefotaxime 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Chlorotetracycline 2 .05 <.01 <.01 <.01 <.01 <.01 <.01

Ciprofloxacin 2 .036 <.005 <.005 <.005 <.005 .17 .17

Clinafloxacin 2 .01 <.005 <.005 <.005 <.005 <.005 <.005

Cloxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Demeclocycline 2 .08 <.01 <.01 <.01 <.01 <.01 <.01

Doxycycline 2 .05 <.01 <.01 <.01 <.01 <.01 .012

Erythromycin (method 1) 1 ND <.009 <.009 <.009 <.009 <.009 <.009

Erythromycin (method 2) 2 .025 <.005 <.005 <.005 <.005 <.005 1.3

Erythromycin-H2O 2 .046 <.005 <.005 <.005 <.005 1.7 5.7

Flumequine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Lincomycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Lomefloxacin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Minocycline 2 .25 <.01 <.01 <.01 <.01 <.01 <.01

Norfloxacin 2 .02 <.005 <.005 <.005 <.005 <.005 .064

Ofloxacin 2 .03 <.005 <.005 <.005 <.005 .97 .34

Ormetoprim 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Oxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Oxolinic acid 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Oxytetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin G 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin V 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Roxithromycin 2 .005 <.005 <.005 <.005 <.005 <.005 .016

Sarafloxacin 2 .03 <.005 <.005 <.005 <.005 <.005 <.005

Sulfachlorpyridazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfadiazine 2 .005 <.005 <.005 <.005 <.005 <.005 .16

Sulfadimethoxine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamerazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamethazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamethoxazole (method 1) 1 ND <.064 <.064 <.064 <.064 <.064 .16

Sulfamethoxazole (method 2) 2 .02 <.005 <.005 <.005 <.005 1.2 .79

Sulfathiazole 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Tetracycline 2 .064 <.01 <.01 <.01 <.01 <.01 .087

Trimethoprim (method 1) 1 ND <.013 <.013 <.013 <.013 .047 .30

Trimethoprim (method 2) 2 .02 <.005 <.005 <.005 <.005 <.005 .37

Tylosin 2 .07 <.005 <.005 <.005 <.005 <.005 <.005

Virginiamycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Supplemental Information 89
Table 19. Analytical results for human and veterinary antibiotic compounds (HVACs).—Continued

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in analyses 

related to occurrence of organic wastewater compounds. Units are micrograms per liter. All compounds are dissolved. <, less than; e, estimated; ND, not determined]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

Date of sample collection 08-19-2003 06-15-2004 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004

Time of sample collection 0930 1730 0915 1825 1400 1105 1145

Compound

Amoxicilin 2 0.05 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Ampicillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Anhd-Cl-tetracycline 2 .3 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Anhydrotetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Azithromycin 1 ND <.004 <.004 <.004 <.004 <.004 <.004 <.004

Cefotaxime 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Chlorotetracycline 2 .05 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Ciprofloxacin 2 .036 <.005 .036 <.005 <.005 <.005 <.005 <.005

Clinafloxacin 2 .01 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Cloxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Demeclocycline 2 .08 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Doxycycline 2 .05 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Erythromycin (method 1) 1 ND <.009 <.009 <.009 <.009 <.009 <.009 <.009

Erythromycin (method 2) 2 .025 <.005 .25 <.005 .081 <.005 <.005 <.005

Erythromycin-H2O 2 .046 .31 .85 .16 .30 <.005 <.005 .060

Flumequine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Lincomycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Lomefloxacin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Minocycline 2 .25 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Norfloxacin 2 .02 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Ofloxacin 2 .03 .27 .067 <.005 <.005 <.005 <.005 <.005

Ormetoprim 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Oxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Oxolinic acid 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Oxytetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin G 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin V 2 .01 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Roxithromycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Sarafloxacin 2 .03 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfachlorpyridazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfadiazine 2 .005 <.005 <.005 <.005 .044 <.005 <.005 <.005

Sulfadimethoxine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamerazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamethazine 2 .005 <.005 <.005 <.005 .0060 <.005 <.005 <.005

Sulfamethoxazole (method 1) 1 ND <.064 <.064 e.042 <.064 <.064 <.064 <.064

Sulfamethoxazole (method 2) 2 .02 .56 .22 .67 .12 <.005 <.005 .014

Sulfathiazole 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Tetracycline 2 .064 <.01 <.01 <.01 <.01 <.01 <.01 <.01

Trimethoprim (method 1) 1 ND .013 .049 .016 e.010 <.013 <.013 <.013

Trimethoprim (method 2) 2 .02 <.005 .11 <.005 .042 <.005 <.005 <.005

Tylosin 2 .07 <.005 <.005 <.005 <.005 <.005 <.005 <.005

Virginiamycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005 <.005

90 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 19. Analytical results for human and veterinary antibiotic compounds (HVACs).—Continued

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in analyses 

related to occurrence of organic wastewater compounds. Units are micrograms per liter. All compounds are dissolved. <, less than; e, estimated; ND, not determined]

Analytical

method

number

Study

reporting

level

Station identification and name (site label)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

Date of sample collection 08-21-2003 10-21-2003 06-16-2004 08-21-2003 10-22-2003 06-16-2004

Time of sample collection 0900 1240 1435 1100 0935 1615

Compound

Amoxicilin 2 0.05 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Ampicillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Anhd-Cl-tetracycline 2 .3 <.01 <.01 <.01 <.01 <.01 <.01

Anhydrotetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01

Azithromycin 1 ND <.004 <.004 <.004 <.004 <.004 <.004

Cefotaxime 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Chlorotetracycline 2 .05 <.01 <.01 <.01 <.01 <.01 <.01

Ciprofloxacin 2 .036 <.005 <.005 <.005 <.005 <.005 <.005

Clinafloxacin 2 .01 <.005 <.005 <.005 <.005 <.005 <.005

Cloxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Demeclocycline 2 .08 <.01 <.01 <.01 <.01 <.01 <.01

Doxycycline 2 .05 <.01 <.01 <.01 <.01 <.01 <.01

Erythromycin (method 1) 1 ND <.009 <.009 <.009 <.009 <.009 <.009

Erythromycin (method 2) 2 .025 <.005 <.005 .043 <.005 <.005 .014

Erythromycin-H2O 2 .046 <.005 <.005 .071 <.005 <.005 .063

Flumequine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Lincomycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Lomefloxacin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Minocycline 2 .25 <.01 <.01 <.01 <.01 <.01 <.01

Norfloxacin 2 .02 <.005 <.005 <.005 <.005 <.005 <.005

Ofloxacin 2 .03 <.005 <.005 <.005 <.005 <.005 <.005

Ormetoprim 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Oxacillin 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Oxolinic acid 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Oxytetracycline 2 .15 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin G 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Penicillin V 2 .01 <.01 <.01 <.01 <.01 <.01 <.01

Roxithromycin 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sarafloxacin 2 .03 <.005 <.005 <.005 <.005 <.005 <.005

Sulfachlorpyridazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfadiazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfadimethoxine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamerazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamethazine 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Sulfamethoxazole (method 1) 1 ND <.064 <.064 <.064 <.064 <.064 <.064

Sulfamethoxazole (method 2) 2 .02 <.005 <.005 <.005 <.005 <.005 .012

Sulfathiazole 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Tetracycline 2 .064 <.01 <.01 <.01 <.01 <.01 <.01

Trimethoprim (method 1) 1 ND <.013 <.013 <.013 <.013 <.013 <.013

Trimethoprim (method 2) 2 .02 <.005 <.005 <.005 <.005 <.005 .0060

Tylosin 2 .07 <.005 <.005 <.005 <.005 <.005 <.005

Virginiamycin, dissolved 2 .005 <.005 <.005 <.005 <.005 <.005 <.005

Supplemental Information 91
Table 19. Analytical results for human and veterinary antibiotic compounds (HVACs).—Continued

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in analyses 

related to occurrence of organic wastewater compounds. Units are micrograms per liter. All compounds are dissolved. <, less than; e, estimated; ND, not determined]

Analytical

method

number

Study 

reporting level

Station identification and name (site label)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)

441434096482500

Brookings wastwater effluent near

Brookings, SD

(BK-WWE)

Date of sample collection 08-21-2003 06-17-2004 08-22-2003 06-17-2004

Time of sample collection 1230 1140 0915 0950

Compound

Amoxicilin 2 0.05 <0.01 <0.01 <0.01 <0.01

Ampicillin 2 .01 <.01 <.01 <.01 <.01

Anhd-Cl-tetracycline 2 .3 <.01 <.01 <.01 <.01

Anhydrotetracycline 2 .15 <.01 <.01 <.01 <.01

Azithromycin 1 ND <.004 <.004 <.004 <.004

Cefotaxime 2 .01 <.01 <.01 <.01 <.01

Chlorotetracycline 2 .05 <.01 <.01 <.01 <.01

Ciprofloxacin 2 .036 <.005 <.005 <.005 .051

Clinafloxacin 2 .01 <.005 <.005 <.005 <.005

Cloxacillin 2 .01 <.01 <.01 <.01 <.01

Demeclocycline 2 .08 <.01 <.01 <.01 <.01

Doxycycline 2 .05 <.01 <.01 <.01 <.01

Erythromycin (method 1) 1 ND <.009 <.009 <.009 <.009

Erythromycin (method 2) 2 .025 <.005 <.005 <.005 .71

Erythromycin-H2O 2 .046 <.005 .048 <.005 2.0

Flumequine 2 .005 <.005 <.005 <.005 <.005

Lincomycin 2 .005 <.005 <.005 <.005 <.005

Lomefloxacin 2 .005 <.005 <.005 <.005 <.005

Minocycline 2 .25 <.01 <.01 <.01 <.01

Norfloxacin 2 .02 <.005 <.005 <.005 <.005

Ofloxacin 2 .03 <.005 <.005 <.005 .051

Ormetoprim 2 .005 <.005 <.005 <.005 <.005

Oxacillin 2 .01 <.01 <.01 <.01 <.01

Oxolinic acid 2 .005 <.005 <.005 <.005 <.005

Oxytetracycline 2 .15 <.01 <.01 <.01 <.01

Penicillin G 2 .01 <.01 <.01 <.01 <.01

Penicillin V 2 .01 <.01 <.01 <.01 <.01

Roxithromycin 2 .005 <.005 <.005 <.005 <.005

Sarafloxacin 2 .03 <.005 <.005 <.005 <.005

Sulfachlorpyridazine 2 .005 <.005 <.005 <.005 <.005

Sulfadiazine 2 .005 <.005 <.005 <.005 .084

Sulfadimethoxine 2 .005 <.005 <.005 <.005 <.005

Sulfamerazine 2 .005 <.005 <.005 <.005 <.005

Sulfamethazine 2 .005 <.005 <.005 <.005 .01

Sulfamethoxazole (method 1) 1 ND <.064 <.064 <.064 .14

Sulfamethoxazole (method 2) 2 .02 <.005 .013 <.005 .50

Sulfathiazole 2 .005 <.005 <.005 <.005 <.005

Tetracycline 2 .064 <.01 <.01 <.01 <.01

Trimethoprim (method 1) 1 ND <.013 <.013 .013 .11

Trimethoprim (method 2) 2 .02 <.005 <.005 <.005 .16

Tylosin 2 .07 <.005 <.005 <.005 <.005

Virginiamycin 2 .005 <.005 <.005 <.005 <.005

92 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 19. Analytical results for human and veterinary antibiotic compounds (HVACs).—Continued

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in analyses 

related to occurrence of organic wastewater compounds. Units are micrograms per liter. All compounds are dissolved. <, less than; e, estimated; ND, not determined]

Analytical

method

number

Study 

reporting

level

Station identification and name (site label)

441316096483300

Big Sioux River below wastewater

effluent, near Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek, at Medary, SD

(BK-DS2)

Date of sample collection 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample collection 1015 1215 1140 1645

Compound

Amoxicilin 2 0.05 <0.01 <0.01 <0.01 <0.01

Ampicillin 2 .01 <.01 <.01 <.01 <.01

Anhd-Cl-tetracycline 2 .3 <.01 <.01 <.01 <.01

Anhydrotetracycline 2 .15 <.01 <.01 <.01 <.01

Azithromycin 1 ND <.004 <.004 <.004 <.004

Cefotaxime 2 .01 <.01 <.01 <.01 <.01

Chlorotetracycline 2 .05 <.01 <.01 <.01 <.01

Ciprofloxacin 2 .036 <.005 <.005 <.005 <.005

Clinafloxacin 2 .01 <.005 <.005 <.005 <.005

Cloxacillin 2 .01 <.01 <.01 <.01 <.01

Demeclocycline 2 .08 <.01 <.01 <.01 <.01

Doxycycline 2 .05 <.01 <.01 <.01 <.01

Erythromycin (method 1) 1 ND <.009 <.009 <.009 <.009

Erythromycin (method 2) 2 .025 <.005 .017 <.005 .017

Erythromycin-H2O 2 .046 <.005 .065 <.005 .060

Flumequine 2 .005 <.005 <.005 <.005 <.005

Lincomycin 2 .005 <.005 <.005 <.005 <.005

Lomefloxacin 2 .005 <.005 <.005 <.005 <.005

Minocycline 2 .25 <.01 <.01 <.01 <.01

Norfloxacin 2 .02 <.005 <.005 <.005 <.005

Ofloxacin 2 .03 <.005 <.005 <.005 <.005

Ormetoprim 2 .005 <.005 <.005 <.005 <.005

Oxacillin 2 .01 <.01 <.01 <.01 <.01

Oxolinic acid 2 .005 <.005 <.005 <.005 <.005

Oxytetracycline 2 .15 <.01 <.01 <.01 <.01

Penicillin G 2 .01 <.01 <.01 <.01 <.01

Penicillin V 2 .01 <.01 <.01 <.01 <.01

Roxithromycin 2 .005 <.005 <.005 <.005 <.005

Sarafloxacin 2 .03 <.005 <.005 <.005 <.005

Sulfachlorpyridazine 2 .005 <.005 <.005 <.005 <.005

Sulfadiazine 2 .005 <.005 <.005 <.005 <.005

Sulfadimethoxine 2 .005 <.005 <.005 <.005 <.005

Sulfamerazine 2 .005 <.005 <.005 <.005 <.005

Sulfamethazine 2 .005 <.005 <.005 <.005 <.005

Sulfamethoxazole (method 1) 1 ND <.064 <.064 <.064 <.064

Sulfamethoxazole (method 2) 2 .02 <.005 .014 <.005 .020

Sulfathiazole 2 .005 <.005 <.005 <.005 <.005

Tetracycline 2 .064 <.01 <.01 <.01 <.01

Trimethoprim (method 1) 1 ND <.013 <.013 <.013 <.013

Trimethoprim (method 2) 2 .02 <.005 <.005 <.005 <.005

Tylosin 2 .07 <.005 <.005 <.005 <.005

Virginiamycin 2 .005 <.005 <.005 <.005 <.005

Supplemental Information 93
Table 20. Analytical results for major agricultural herbicides (MAHs).

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; <, less than]

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004

Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730

Compound

Atrazine 3 0.0002 e0.10 e0.21 <0.5 e0.19 <0.5 e0.18 <0.5 e0.16

Metolachlor 3 .028 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Prometon 3 .02 <.5 <.5 <.5 <.5 e.068 <.5 e.10 <.5

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

Date of sample collection 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004

Time of sample collection 0915 1825 1400 1105 1145 0900 1240 1435

Compound

Atrazine 3 0.0002 <0.5 e0.26 <0.5 e0.050 0.95 e0.055 e0.059 e0.18

Metolachlor 3 .028 <.5 <.5 <.5 <.5 e.035 <.5 <.5 <.5

Prometon 3 .02 e.068 <.5 e.093 e.055 <.5 <.5 <.5 <.5

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)

Date of sample collection 08-21-2003 10-22-2003 06-16-2004 08-21-2003 06-17-2004

Time of sample collection 1100 0935 1615 1230 1140

Compound

Atrazine 3 0.0002 <0.5 e0.050 1.5 <0.5 1.2

Metolachlor 3 .028 <.5 <.5 e.055 <.5 e.035

Prometon 3 .02 e.076 e.061 e.069 e.095 <.5

Analytical

method

number

Study 

reporting 

level

Station identification and name (site label)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

Wastewater effluent, near

Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek, at Medary, SD

(BK-DS2)

Date of sample collection 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample collection 0915 0950 1015 1215 1140 1645

Compound

Atrazine 3 0.0002 <0.5 e0.086 <0.5 0.84 <0.5 1.3

Metolachlor 3 .028 <.5 <.5 <.5 e.030 <.5 e.028

Prometon 3 .02 e.05 <.5 e.081 e.044 e.099 <.5

94 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Supplemental Information 95

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004

Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730

Compound

1,4-dichlorobenzene, whole 

water

3 ND <0.5 <0.5 <0.5 <0.5 e0.068 e0.28 <0.5 <0.5

2,2’,4,4’-tetrabromodiphenyl 

ether, whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

3,4-dichlorophenyl isocyanate, 

whole water

3 ND <.5 <.5 <.5 <.5 <.5 e0.16 <.5 <.5

3-methyl-1H-indole (skatol), 

whole water

3 .02 <1 <1 <1 <1 <1 <1 <1 <1

3-tert-butyl-4-hydroxy anisole 

(BHA), whole water

3 ND <5 <5 <5 <5 <5 <5 <5 <5

4-cumylphenol, whole water 3 1 <1 <1 <1 <1 <1 <1 <1 <1

4-normal-octylphenol, whole 

water

3 1 <1 <1 <1 <1 <1 <1 <1 <1

4-tert-octylphenol, whole water 3 .26 <1 <1 <1 <1 <1 <1 e.14 <1

5-methyl-1H-benzotriazole, 

whole water

3 .33 <2 <2 <2 <2 e.45 e.89 <2 <2

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

3 .048 <.5 <.5 <.5 <.5 1.1 1.6 .59 .51

Acetophenone, whole water 3 .08 <.5 <.5 <.5 <.5 e.12 <.5 e.18 <.5

Anthraquinone, whole water 3 .96 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Benzophenone, whole water 3 .025 <.5 <.5 <.5 <.5 e.078 e.091 e.068 <.5

Bis(2-ethylhexyl) phthalate, 

whole water

3 ND <2 7.2 <2 <2 e1.9 <2 <2 <2

Bisphenol-A, whole water 3 .069 e.19 <1 <1 <1 <1 <1 <1 <1

Bromacil, whole water 3 .068 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Camphor, whole water 3 .07 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Carbaryl, whole water 3 ND <1 <1 <1 <1 <1 <1 <1 <1

Chlorpyrifos, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

N,N-diethyl-meta-toluamide 

(DEET), whole water

3 .08 e.11 <.5 e.058 <.5 e.083 e.090 e.11 e.052

Diazinon, whole water 3 .027 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Dichlorvos, whole water 3 1 <1 <1 <1 <1 <1 <1 <1 <1

Diethyl phthalate, whole water 3 .55 <.5 <.5 .55 <.5 <.5 <.5 <.5 <.5

D-Limonene, whole water 3 ND <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5
96 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

1,3,4,6,7,8-hexahydro4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran 

(HHCB), whole water

3 0.032 <0.5 <0.5 <0.5 <0.5 e0.19 e0.16 e0.11 e0.060

Indole, whole water 3 .015 e.036 <.5 <.5 <.5 e.034 <.5 e.043 <.5

Isoborneol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Isophorone, whole water 3 .047 e.050 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Isoquinoline, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Menthol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Metalaxyl, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Methyl salicylate, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Nonylphenol diethoxylate 

(NP2EO), whole water

3 .55 <5 <5 <5 <5 <5 e.91 <5 e.55

Nonylphenol monoethoxylate 

(NP1EO), whole water

3 .39 <2 <2 <2 <2 <2 e.54 <2 e.39

Octylphenol diethoxylate 

(OP2EO), whole water

3 .14 <1 <1 <1 <1 <1 <1 <1 <1

Octylphenol monoethoxylate 

(OP1EO), whole water

3 1 <1 <1 <1 <1 <1 <1 <1 <1

para-cresol, whole water 3 .03 <1 <1 <1 <1 e.084 <1 <1 <1

para-nonylphenol (NP), whole 

water

3 .64 <5 <5 <5 <5 <5 e.84 <5 e.84

Pentachlorophenol, whole water 3 2 <2 <2 <2 <2 <2 <2 <2 <2

Phenol, whole water 3 .94 <.5 <.5 <.5 <.5 <.5 <.5 e0.22 <.5

Tetrachloroethylene, whole water 3 ND <.5 <.5 <.5 <.5 <.5 e.41 <.5 e.22

Tributyl phosphate, whole water 3 .02 <.5 <.5 e.046 <.5 e.15 e.11 e.11 e.054

Triclosan, whole water 3 .084 <1 <1 <1 <1 e.15 <1 e.096 <1

Triethyl citrate (ethyl citrate), 

whole water

3 .048 <.5 <.5 <.5 <.5 e.34 e.35 e.20 e.097

Triphenyl phosphate, whole 

water

3 .015 <.5 <.5 <.5 <.5 e.047 e.063 e.024 <.5

Tri(2-butoxyethyl)phosphate, 

whole water

3 .13 <.5 <.5 e.35 <.5 e.23 <.5 .63 e.35

Tri(2-chloroethyl)phosphate, 

whole water

3 .056 <.5 <.5 <.5 <.5 28 e.35 12 e.13

Tri(dichloroisopropyl)phosphate, 

whole water

3 .047 <.5 <.5 <.5 <.5 e.49 e.30 e.28 <.5

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent,

near Watertown, SD

(WT-DS1)
Supplemental Information 97

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479520

Big Sioux River below

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

Date of sample collection 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004

Time of sample collection 0915 1825 1400 1105 1145 0900 1240 1435

Compound

1,4-dichlorobenzene, whole 

water

3 ND <0.5 <0.5 e0.47 e0.083 <0.5 <0.5 <0.5 <0.5

2,2’,4,4’-tetrabromodiphenyl 

ether, whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

3,4-dichlorophenyl isocyanate, 

whole water

3 ND <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

3-methyl-1H-indole (skatol), 

whole water

3 .02 <1 <1 <1 <1 <1 <1 <1 <1

3-tert-butyl-4-hydroxy anisole 

(BHA), whole water

3 ND <5 <5 e.16 <5 <5 <5 <5 <5

4-cumylphenol, whole water 3 1 <1 <1 <1 <1 <1 <1 <1 <1

4-normal-octylphenol, whole 

water

3 1 <1 <1 <1 <1 <1 <1 <1 <1

4-tert-octylphenol, whole water 3 .26 <1 <1 e.14 <1 <1 <1 e.091 <1

5-methyl-1H-benzotriazole, 

whole water

3 .33 <2 <2 <2 <2 <2 <2 e.36 <2

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

3 .048 e.053 e.16 <.5 <.5 <.5 <.5 <.5 <.5

Acetophenone, whole water 3 .08 e.082 <.5 <.5 e.23 <.5 <.5 e.18 <.5

Anthraquinone, whole water 3 .96 <.5 <.5 <.5 <.5 <.5 e.092 <.5 <.5

Benzophenone, whole water 3 .025 e.064 <.5 <.5 <.5 <.5 e.029 <.5 <.5

Bis(2-ethylhexyl) phthalate, 

whole water

3 ND <2 <2 <2 <2 <2 <2 <2 <2

Bisphenol-A, whole water 3 .069 e.087 <1 e.069 <1 <1 <1 e.072 <1

Bromacil, whole water 3 .068 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Camphor, whole water 3 .07 <.5 <.5 <.5 <.5 <.5 <.5 e.070 <.5

Carbaryl, whole water 3 ND <1 <1 <1 <1 <1 <1 <1 <1

Chlorpyrifos, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

N,N-diethyl-meta-toluamide 

(DEET), whole water

3 .08 e.075 e.18 e.063 e.029 <.5 e.23 e.20 e.085

Diazinon, whole water 3 .027 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Dichlorvos, whole water 3 1 <1 <1 <1 <1 <1 <1 <1 <1

Diethyl phthalate, whole water 3 .55 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

D-Limonene, whole water 3 ND <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5
98 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

1,3,4,6,7,8-hexahydro4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran 

(HHCB), whole water

3 0.032 e0.033 e0.040 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

Indole, whole water 3 .015 e.070 <.5 e.043 e.024 <.5 <.5 e.016 <.5

Isoborneol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Isophorone, whole water 3 .047 <.5 <.5 e.035 e.026 <.5 e.050 e.047 <.5

Isoquinoline, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Menthol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Metalaxyl, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Methyl salicylate, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Nonylphenol diethoxylate 

(NP2EO), whole water

3 .55 <5 <5 <5 e3.3 <5 <5 e5.1 <5

Nonylphenol monoethoxylate 

(NP1EO), whole water

3 .39 <2 <2 <2 e1.7 <2 <2 e2.9 <2

Octylphenol diethoxylate 

(OP2EO), whole water

3 .14 <1 <1 <1 e.15 <1 <1 e.26 <1

Octylphenol monoethoxylate 

(OP1EO), whole water

3 1 <1 <1 <1 <1 <1 <1 <1 <1

para-cresol, whole water 3 .03 <1 <1 <1 <1 <1 <1 e.030 <1

para-nonylphenol (NP), whole 

water

3 .64 <5 <5 <5 <5 <5 <5 <5 <5

Pentachlorophenol, whole water 3 2 <2 <2 <2 <2 <2 <2 <2 <2

Phenol, whole water 3 .94 e.19 <.5 e.23 <.5 <.5 <.5 <.5 <.5

Tetrachloroethylene, whole water 3 ND <.5 e.020 <.5 <.5 <.5 <.5 <.5 <.5

Tributyl phosphate, whole water 3 .02 e.073 <.5 <.5 e.12 <.5 <.5 <.5 <.5

Triclosan, whole water 3 .084 e.084 <1 <1 <1 <1 <1 <1 <1

Triethyl citrate (ethyl citrate), 

whole water

3 .048 <.5 e.048 <.5 <.5 <.5 <.5 <.5 <.5

Triphenyl phosphate, whole 

water

3 .015 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Tri(2-butoxyethyl)phosphate, 

whole water

3 .13 e.23 0.52 e.29 <.5 <.5 <.5 <.5 <.5

Tri(2-chloroethyl)phosphate, 

whole water

3 .056 e.20 <.5 e.066 e.11 <.5 e.067 e.13 e.11

Tri(dichloroisopropyl)phosphate, 

whole water

3 .047 e.18 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479520

Big Sioux River below

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)
Supplemental Information 99

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)

Date of sample collection 08-21-2003 10-22-2003 06-16-2004 08-21-2003 06-17-2004

Time of sample collection 1100 0935 1615 1230 1140

Compound

1,4-dichlorobenzene, whole 

water

3 ND e0.18 e0.093 <0.5 e0.32 <0.5

2,2’,4,4’-tetrabromodiphenyl 

ether, whole water

3 .5 <.5 <.5 <.5 <.5 <.5

3,4-dichlorophenyl isocyanate, 

whole water

3 ND <.5 <.5 <.5 <.5 <.5

3-methyl-1H-indole (skatol), 

whole water

3 .02 <1 <1 <1 <1 <1

3-tert-butyl-4-hydroxy anisole 

(BHA), whole water

3 ND <5 <5 <5 <5 <5

4-cumylphenol, whole water 3 1 <1 <1 <1 <1 <1

4-normal-octylphenol, whole 

water

3 1 <1 <1 <1 <1 <1

4-tert-octylphenol, whole water 3 .26 <1 e.085 <1 <1 <1

5-methyl-1H-benzotriazole, 

whole water

3 .33 <2 <2 <2 <2 <2

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

3 .048 <.5 <.5 <.5 <.5 <.5

Acetophenone, whole water 3 .08 <.5 e.17 <.5 <.5 <.5

Anthraquinone, whole water 3 .96 e.062 <.5 <.5 <.5 <.5

Benzophenone, whole water 3 .025 <.5 <.5 <.5 <.5 <.5

Bis(2-ethylhexyl) phthalate, 

whole water

3 ND <2 <2 <2 <2 <2

Bisphenol-A, whole water 3 .069 <1 <1 <1 <1 <1

Bromacil, whole water 3 .068 <.5 <.5 <.5 <.5 <.5

Camphor, whole water 3 .07 <.5 <.5 <.5 <.5 <.5

Carbaryl, whole water 3 ND <1 <1 <1 <1 <1

Chlorpyrifos, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

N,N-diethyl-meta-toluamide 

(DEET), whole water

3 .08 e.052 e.043 e.036 e.048 e.077

Diazinon, whole water 3 .027 <.5 <.5 <.5 <.5 <.5

Dichlorvos, whole water 3 1 <1 <1 <1 <1 <1

Diethyl phthalate, whole water 3 .55 <.5 <.5 <.5 <.5 <.5

D-Limonene, whole water 3 ND <.5 <.5 <.5 <.5 <.5
100 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

1,3,4,6,7,8-hexahydro4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran 

(HHCB), whole water

3 0.032 <0.5 <0.5 <0.5 <0.5 <0.5

Indole, whole water 3 .015 <.5 e.083 <.5 <.5 <.5

Isoborneol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Isophorone, whole water 3 .047 <.5 e.028 <.5 <.5 <.5

Isoquinoline, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Menthol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Metalaxyl, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Methyl salicylate, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Nonylphenol diethoxylate 

(NP2EO), whole water

3 .55 <5 e3.4 <5 <5 <5

Nonylphenol monoethoxylate 

(NP1EO), whole water

3 .39 <2 e2.2 <2 <2 <2

Octylphenol diethoxylate 

(OP2EO), whole water

3 .14 <1 e.16 <1 <1 <1

Octylphenol monoethoxylate 

(OP1EO), whole water

3 1 <1 <1 <1 <1 <1

para-cresol, whole water 3 .03 <1 <1 <1 <1 <1

para-nonylphenol (NP), whole 

water

3 .64 <5 <5 <5 <5 <5

Pentachlorophenol, whole water 3 2 <2 <2 <2 <2 <2

Phenol, whole water 3 .94 <.5 <.5 <.5 e.13 <.5

Tetrachloroethylene, whole water 3 ND <.5 <.5 <.5 <.5 <.5

Tributyl phosphate, whole water 3 .02 <.5 e.13 <.5 <.5 <.5

Triclosan, whole water 3 .084 <1 <1 <1 <1 <1

Triethyl citrate (ethyl citrate), 

whole water

3 .048 <.5 <.5 <.5 <.5 <.5

Triphenyl phosphate, whole 

water

3 .015 <.5 <.5 <.5 <.5 <.5

Tri(2-butoxyethyl)phosphate, 

whole water

3 .13 <.5 <.5 e.19 e.19 <.5

Tri(2-chloroethyl)phosphate, 

whole water

3 .056 e.060 e.12 <.5 e.056 <.5

Tri(dichloroisopropyl)phosphate, 

whole water

3 .047 <.5 <.5 <.5 <.5 <.5

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441841096521400

Big Sioux River below wastewater

wetland, near Volga, SD

(VL-DS1)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)
Supplemental Information 101

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

Wastewater effluent, near

Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek, at Medary, SD

(BK-DS2)

Date of sample collection 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample collection 0915 0950 1015 1215 1140 1645

Compound

1,4-dichlorobenzene, whole 

water

3 ND e0.13 e0.16 e0.22 <0.5 e0.25 <0.5

2,2’,4,4’-tetrabromodiphenyl 

ether, whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5

3,4-dichlorophenyl isocyanate, 

whole water

3 ND <.5 <.5 <.5 <.5 <.5 <.5

3-methyl-1H-indole (skatol), 

whole water

3 .02 <1 <1 <1 <1 <1 <1

3-tert-butyl-4-hydroxy anisole 

(BHA), whole water

3 ND <5 <5 <5 <5 <5 <5

4-cumylphenol, whole water 3 1 <1 <1 <1 <1 <1 <1

4-normal-octylphenol, whole 

water

3 1 <1 <1 <1 <1 <1 <1

4-tert-octylphenol, whole water 3 .26 <1 <1 <1 <1 <1 <1

5-methyl-1H-benzotriazole, 

whole water

3 .33 e.80 e.84 <2 <2 <2 <2

7-acetyl-1,1,3,4,4,6-hexamethyl 

tetrahydronaphthalene 

(AHTN), whole water

3 .048 2 2.3 e.074 <.5 e.24 <.5

Acetophenone, whole water 3 .08 e.083 <.5 <.5 <.5 <.5 <.5

Anthraquinone, whole water 3 .96 e.058 <.5 <.5 <.5 <.5 <.5

Benzophenone, whole water 3 .025 e.26 e.13 e.042 <.5 e.041 <.5

Bis(2-ethylhexyl) phthalate, 

whole water

3 ND <2 <2 <2 <2 <2 <2

Bisphenol-A, whole water 3 .069 e.13 <1 <1 <1 <1 <1

Bromacil, whole water 3 .068 <.5 <.5 <.5 <.5 <.5 <.5

Camphor, whole water 3 .07 <.5 <.5 <.5 <.5 <.5 <.5

Carbaryl, whole water 3 ND <1 <1 <1 <1 <1 <1

Chlorpyrifos, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

N,N-diethyl-meta-toluamide 

(DEET), whole water

3 .08 e.042 e.038 e.050 e.042 e.051 e.069

Diazinon, whole water 3 .027 <.5 <.5 <.5 <.5 <.5 <.5

Dichlorvos, whole water 3 1 <1 <1 <1 <1 <1 <1

Diethyl phthalate, whole water 3 .55 <.5 <.5 <.5 <.5 <.5 <.5

D-Limonene, whole water 3 ND <.5 <.5 <.5 <.5 <.5 <.5
102 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota

1,3,4,6,7,8-hexahydro4,6,6,7,8,8-hexamethyl 

cyclopenta-g-2-benzopyran 

(HHCB), whole water

3 0.032 e0.44 e0.33 e0.032 <0.5 e0.054 <0.5

Indole, whole water 3 .015 <.5 <.5 <.5 <.5 <.5 <.5

Isoborneol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Isophorone, whole water 3 .047 <.5 <.5 <.5 <.5 <.5 <.5

Isoquinoline, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Menthol, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Metalaxyl, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Methyl salicylate, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Nonylphenol diethoxylate 

(NP2EO), whole water

3 .55 <5 e1.2 <5 <5 <5 <5

Nonylphenol monoethoxylate 

(NP1EO), whole water

3 .39 <2 e.69 <2 <2 <2 <2

Octylphenol diethoxylate 

(OP2EO), whole water

3 .14 <1 <1 <1 <1 <1 <1

Octylphenol monoethoxylate 

(OP1EO), whole water

3 1 <1 <1 <1 <1 <1 <1

para-cresol, whole water 3 .03 <1 <1 <1 <1 <1 <1

para-nonylphenol (NP), whole 

water

3 .64 <5 e.71 <5 <5 <5 <5

Pentachlorophenol, whole water 3 2 <2 <2 <2 <2 <2 <2

Phenol, whole water 3 .94 e.22 0.50 <.5 <.5 <.5 <.5

Tetrachloroethylene, whole water 3 ND <.5 <.5 <.5 <.5 <.5 <.5

Tributyl phosphate, whole water 3 .02 e.38 e.28 e.060 <.5 e.096 <.5

Triclosan, whole water 3 .084 e.13 <1 <1 <1 <1 <1

Triethyl citrate (ethyl citrate), 

whole water

3 .048 e.33 e.36 <.5 <.5 e.052 <.5

Triphenyl phosphate, whole 

water

3 .015 e.017 <.5 <.5 <.5 e.0094 <.5

Tri(2-butoxyethyl)phosphate, 

whole water

3 .13 e.27 <.5 <.5 <.5 <.5 <.5

Tri(2-chloroethyl)phosphate, 

whole water

3 .056 e.32 e.40 e.078 <.5 e.13 <.5

Tri(dichloroisopropyl)phosphate, 

whole water

3 .047 e.19 <.5 e.047 <.5 e.059 <.5

Table 21. Analytical results for household, industrial, and minor agricultural-use compounds (HIACs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

Wastewater effluent, near

Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek, at Medary, SD

(BK-DS2)
Table 22. Analytical results for polyaromatic hydrocarbons (PAHs).

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River

at Broadway, at 

Watertown, SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent, near

Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004

Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730

Compound

1-methylnaphthalene, 

whole water

3 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

2,6-dimethylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

2-methylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Anthracene, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Benzo[a]pyrene, whole 

water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Carbazole, whole water 3 .22 <.5 <.5 <.5 <.5 <.5 <.5 e.048 <.5

Fluoranthene, whole water 3 .15 <.5 <.5 e.027 .031 <.5 <.5 <.5 e.027

Isopropylbenzene 

(cumene), whole water

3 ND <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Naphthalene, whole water 3 .01 <.5 <.5 <.5 e.014 <.5 <.5 <.5 <.5

Phenanthrene, whole water 3 .1 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Pyrene, whole water 3 .04 <.5 <.5 e.026 e.027 <.5 <.5 e.014 e.028

Supplemental Information 103
Table 22. Analytical results for polyaromatic hydrocarbons (PAHs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

Date of sample collection 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004

Time of sample collection 0915 1825 1400 1105 1145 0900 1240 1435

Compound

1-methylnaphthalene, 

whole water

3 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

2,6-dimethylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

2-methylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Anthracene, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Benzo[a]pyrene, whole 

water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Carbazole, whole water 3 .22 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Fluoranthene, whole water 3 .15 e.035 e.025 <.5 <.5 <.5 <.5 <.5 <.5

Isopropylbenzene 

(cumene), whole water

3 ND <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Naphthalene, whole water 3 .01 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Phenanthrene, whole water 3 .1 e.023 e.031 <.5 <.5 <.5 <.5 <.5 <.5

Pyrene, whole water 3 .04 e.031 e.023 <.5 <.5 <.5 <.5 <.5 <.5

104 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 22. Analytical results for polyaromatic hydrocarbons (PAHs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441841096521400

Big Sioux River below wastewater

wetland near Volga, SD

(VL-DS1)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)

Date of sample collection 08-21-2003 10-22-2003 06-16-2004 08-21-2003 06-17-2004

Time of sample collection 1100 0935 1615 1230 1140

Compound

1-methylnaphthalene, 

whole water

3 0.5 <0.5 <0.5 <0.5 <0.5 <0.5

2,6-dimethylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5

2-methylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5

Anthracene, whole water 3 .5 <.5 <.5 <.5 <.5 <.5

Benzo[a]pyrene, whole 

water

3 .5 <.5 <.5 <.5 <.5 <.5

Carbazole, whole water 3 .22 <.5 <.5 <.5 <.5 <.5

Fluoranthene, whole water 3 .15 <.5 <.5 <.5 <.5 <.5

Isopropylbenzene 

(cumene), whole water

3 ND <.5 <.5 <.5 <.5 <.5

Naphthalene, whole water 3 .01 <.5 <.5 <.5 <.5 <.5

Phenanthrene, whole water 3 .1 <.5 <.5 <.5 <.5 <.5

Pyrene, whole water 3 .04 <.5 <.5 <.5 <.5 <.5

Supplemental Information 105
Table 22. Analytical results for polyaromatic hydrocarbons (PAHs).—Continued

[Bold text indicates suspected endocrine-disrupting compound (EDC). Shaded cells indicate concentrations greater than study reporting levels for compounds 

with acceptable quality assurance/quality control, and were used in analyses related to occurrence of organic wastewater compounds. Units are micrograms per 

liter. e, estimated; ND, not determined; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441434096482500

Brookings wastewater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent, near

Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek at Medary, SD

(BK-DS2)

Date of sample collection 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample collection 0915 0950 1015 1215 1140 1645

Compound

1-methylnaphthalene, 

whole water

3 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

2,6-dimethylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5

2-methylnaphthalene, 

whole water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Anthracene, whole water 3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Benzo[a]pyrene, whole 

water

3 .5 <.5 <.5 <.5 <.5 <.5 <.5

Carbazole, whole water 3 .22 <.5 <.5 <.5 <.5 <.5 <.5

Fluoranthene, whole water 3 .15 <.5 <.5 <.5 <.5 <.5 <.5

Isopropylbenzene 

(cumene), whole water

3 ND <.5 <.5 <.5 <.5 <.5 <.5

Naphthalene, whole water 3 .01 <.5 <.5 <.5 <.5 <.5 <.5

Phenanthrene, whole water 3 .1 e.012 <.5 <.5 <.5 <.5 <.5

Pyrene, whole water 3 .04 <.5 <.5 <.5 <.5 <.5 <.5

106 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Table 23. Analytical results for sterol compounds (SCs).

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in 

analyses related to occurrence of organic wastewater compounds. Units are micrograms per liter. ND, not determined; e, estimated; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479500

Big Sioux River at 

Watertown, SD

(WT-US1)

06479512

Big Sioux River at 

Broadway, at Watertown, 

SD

(WT-US2)

445301097055900

Watertown wastewater

effluent at

Watertown, SD

(WT-WWE)

445234097054800

Big Sioux River below 

wastewater effluent, near

Watertown, SD

(WT-DS1)

Date of sample collection 08-18-2003 06-15-2004 08-18-2003 06-15-2004 08-19-2003 06-16-2004 08-19-2003 06-15-2004

Time of sample collection 1045 1030 1200 1200 1305 0925 0930 1730

Compound

3-beta-coprostanol 3 0.26 <2 <2 <2 <2 e1.3 e1.2 e1.0 <2

beta-sitosterol 3 .57 2.2 <2 e1.6 <2 e.94 <2 e.94 <2

beta-stigmastanol 3 ND <2 <2 <2 <2 <2 <2 <2 <2

Cholesterol 3 .64 3.2 <2 e1.8 <2 3.0 2.9 e1.7 e1.8

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

06479520

Big Sioux River below 

Watertown, SD

(WT-DS2)

442026096533600

Big Sioux River near Volga, SD

(VL-US1)

441913096533400

Volga wastewater wetland

at Volga, SD

(VL-WWE)

Date of sample collection 08-20-2003 06-15-2004 08-20-2003 10-21-2003 06-16-2004 08-21-2003 10-21-2003 06-16-2004

Time of sample collection 0915 1825 1400 1105 1145 0900 1240 1435

Compound

3-beta-coprostanol 3 0.26 e0.75 <2 <2 e0.54 <2 <2 e0.78 <2

beta-sitosterol 3 .57 e1.7 <2 e1.6 e1.1 <2 <2 2 <2

beta-stigmastanol 3 ND <2 <2 <2 e.88 <2 <2 e1.8 <2

Cholesterol 3 .64 2.3 e1.5 3.6 e1.3 <2 e1.4 2.8 2.1

Supplemental Information 107
Table 23. Analytical results for sterol compounds (SCs).—Continued

[Shaded cells indicate concentrations greater than study reporting levels for compounds with acceptable quality assurance/quality control, and were used in 

analyses related to occurrence of organic wastewater compounds. Units are micrograms per liter. e, estimated; <, less than]

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441841096521400

Big Sioux River below wastewater

wetland, near Volga

(VL-DS1)

441421096491200

Big Sioux River above wastewater

effluent, near Brookings, SD

(VL-DS2/BK-US1)

Date of sample collection 08-21-2003 10-22-2003 06-16-2004 08-21-2003 06-17-2004

Time of sample collection 1100 0935 1615 1230 1140

Compound

3-beta-coprostanol 3 0.26 <2 e0.73 <2 <2 <2

beta-sitosterol 3 .57 e1.4 2.4 <2 e1.0 <2

beta-stigmastanol 3 ND <2 e1.3 <2 <2 <2

Cholesterol 3 .64 e1.9 2.3 <2 e1.0 <2

Analytical 

method 

number

Study 

reporting 

level

Station identification and name (site label)

441434096482500

Brookings wastwater effluent 

near Brookings, SD

(BK-WWE)

441316096483300

Big Sioux River below 

wastewater effluent near

Brookings, SD

(BK-DS1)

441151096472200

Big Sioux River above Medary 

Creek, at Medary, SD

(BK-DS2)

Date of sample collection 08-22-2003 06-17-2004 08-22-2003 06-18-2004 08-22-2003 06-17-2004

Time of sample collection 0915 0950 1015 1215 1140 1645

Compound

3-beta-coprostanol 3 0.26 e1.1 <2 <2 <2 <2 <2

beta-sitosterol 3 .57 e.89 <2 e1.2 <2 e1.1 <2

beta-stigmastanol 3 ND <2 <2 <2 <2 <2 <2

Cholesterol 3 .64 e1.6 e1.8 e1.5 <2 e1.4 e.96

108 Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota
Edited by Ella M. Decker.

Graphics by Connie J. Ross.

Prepared by the USGS South Dakota Water Science Center:

This publication is available online at

 http://pubs.water.usgs.gov/sir20055249

U.S. Geological Survey

1608 Mt. View Road

Rapid City, SD 57702

Information regarding the water resources in South Dakota is available at

 http://sd.water.usgs.gov/
Sando and others—Occurrence of Organic Wastewater Compounds in the Upper Big Sioux River Basin, South Dakota, 2003–2004—SIR 2005–5249

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