7

Method Description, Quality Assurance, Environmental Data, 

and other Information for Analysis of Pharmaceuticals in 

Wastewater-Treatment-Plant Effluents, Streamwater, and 

Reservoirs, 2004-2009

Open-File Report 2010–1102

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

New York State Department of Environmental Conservation 

Method Description, Quality Assurance, 

Environmental Data, and other Information for 

Analysis of Pharmaceuticals in WastewaterTreatment-Plant Effluents, Streamwater, and 

Reservoirs, 2004-2009

By Patrick J. Phillips, Steven G. Smith, Dana W. Kolpin, Steven D. Zaugg, Herbert T. Buxton, and Edward 

T. Furlong

Open-File Report 2010–1102

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia 2010

For product and ordering information:

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

Telephone: 1-888-ASK-USGS

For more information on the USGS—the Federal source for science about the Earth,

its natural and living resources, natural hazards, and the environment:

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

Telephone: 1-888-ASK-USGS

Suggested citation:

Phillips, P.J., Smith, S.G., Kolpin, D.W., Zaugg, S.D., Buxton, H.T., and Furlong, E.T., 2010, Method 

Description, Quality Assurance, Environmental Data, and other Information for Analysis of 

Pharmaceuticals in Wastewater-Treatment-Plant Effluents, Streamwater, and Reservoirs, 2004-2009: 

U.S. Geological Survey Open-File Report 2010-1102, 36 p., available at 

http://pubs.usgs.gov/of/2010/1102/.

Any use of trade, product, or firm names 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 material contained within this report.
iii

Contents

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

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

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

Sampling Network...................................................................................................................................................... 3

Information on Pharmaceuticals Formulated at PFFs.................................................................................................... 5

Method Description........................................................................................................................................................ 6

Sample Preparation, Apparatus, Instrumentation, and Standards ............................................................................. 6

Qualitative and Tentative Identification of Analytes.................................................................................................... 8

Quantitation of Analytes ............................................................................................................................................. 9

Quantifying High Concentrations............................................................................................................................ 9

Quantifying Low Concentrations........................................................................................................................... 10

Method Performance................................................................................................................................................ 10

Spikes................................................................................................................................................................... 10

Reagent Set Spikes .......................................................................................................................................... 10

Matrix Spikes .................................................................................................................................................... 11

NY3 Effluent Matrix Spikes............................................................................................................................ 12

NY1 Effluent Matrix Spikes............................................................................................................................ 12

NY4 Effluent Matrix Spikes............................................................................................................................ 13

NY1 Upstream Matrix Spikes ........................................................................................................................ 14

Summary of Reagent Set and Matrix Spikes................................................................................................. 15

Method Detection Limit......................................................................................................................................... 15

Estimation of Precision......................................................................................................................................... 17

Holding Time Study .............................................................................................................................................. 17

Environmental Data ..................................................................................................................................................... 19

Quality-Assurance Data ........................................................................................................................................... 19

Blank Data............................................................................................................................................................ 19

Replicate Data...................................................................................................................................................... 19

Environmental Data for Pharmaceuticals in Wastewater-Treatment Plants, and in Streamwater and Reservoir Water

................................................................................................................................................................................. 20

Concentrations in Samples from National Survey of Wastewater-Treatment-Plant Effluent................................. 20

Concentrations in Effluent Samples from Wastewater-Treatment Plants NY1, NY2 and NY3.............................. 21

Concentrations in Samples of Streamwater Collected Downstream from WWTP Discharge Points of NY1, NY2, 

and NY3 ............................................................................................................................................................... 22

Concentrations in Samples of Streamwater Collected Upstream from WWTP NY1, NY2, and NY3 Discharge 

Points ................................................................................................................................................................... 27

Concentrations in Samples collected from Reservoirs and Additional Streams Downstream from NY2 Effluent 

Discharge Point .................................................................................................................................................... 28

Data on Qualitatively and Tentatively Identified Compounds................................................................................ 29

Flow Data for Selected WWTP Effluent Samples and Streamwater Samples.......................................................... 32

Summary ..................................................................................................................................................................... 32

Acknowledgments........................................................................................................................................................ 33

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

Figures

Graphs showing:

1. Concentrations of seven pharmaceutical compounds analyzed for in effluent from 23 wastewater treatment plants 

across the United States during 2006-09. ...............................................................................................................20

2. Total concentration of seven pharmaceutical compounds detected in effluent from wastewater treatment plants 

(WWTPs) (A) in individual samples from 23 plants across the United States 2006-09, and (B) in multiple samples 

from NY1, NY2, and NY3 in New York State, 2004-09............................................................................................21

3. Concentrations of seven pharmaceuticals in samples of effluent from wastewater treatment plants (WWTPs) NY1, 

NY2, and NY3, New York State, during 2004-09.....................................................................................................23

4. Concentrations of carisoprodol and butalbital in samples collected (A) from NY2 effluent, (B) from the NY2 effluent 

discharge point, and (C) at the reservoir site 30 kilometers downstream from the NY2 site in New York State, 

2004-09...................................................................................................................................................................24

5. Concentrations of (A) oxycodone and butalbital, and (B) metaxalone and methadone in samples from NY3 effluent, 

2004-09...................................................................................................................................................................25

6. Concentrations of seven pharmaceuticals in samples collected downstream from the effluent discharge points of 

wastewater treatment plants NY1, NY2, and NY3 in New York State during 2004-09. ...........................................26

7. Ratio of the concentrations of butalbital and carisoprodol in streamwater downstream from NY2 effluent discharge 

point to the concentrations of the pharmaceutical in NY2 effluent as a function of the percentage of streamflow 

consisting of wastewater treatment plant NY2 effluent, 2004-09.............................................................................27

Tables

1. Descriptions of 23 wastewater-treatment plants sampled once during 2006-09 in a national survey of 

wastewater-treatment-plant effluent and three wastewater-treatment plants in New York State sampled multiple 

times during 2004-09. ............................................................................................................................................4

2. Number of effluent samples collected from wastewater treatment plants and streamwater samples collected at 

sites NY1, NY2, and NY3 in New York State during 2004-09, and types of treatment provided by each 

wastewater treatment plant....................................................................................................................................5

3. Distance downstream and effluent dilution at three stream sampling sites in New York State, 2004-09. ..............5

4. Sites sampled across the United States during 2004-09 (Excel format). ...............................................................5

5. List of seven target pharmaceuticals with chemical properties and method detection limit....................................6

6. Retention time, quantitation ion, and confirmation ions for target analytes, surrogate compounds, and internal 

standard reference compounds. ............................................................................................................................7

7. Measured retention time, quantitation ion, and confirmation ions for qualitatively identified compounds...............9

8. Mean recovery and relative standard deviation of pharmaceuticals from reagent set spike samples analyzed 

before 2009..........................................................................................................................................................11

9. Mean recovery and relative standard deviation of pharmaceuticals from reagent set spike samples for 2009. ...11
v

10. Mean spike recoveries and percent relative standard deviations for six replicate matrix spikes of effluent from 

wastewater treatment plant NY3 in New York State, fortified over a range of high concentrations for six analytes.

.............................................................................................................................................................................12

11. Mean spike recoveries and percent relative standard deviations for five replicate matrix spikes of effluent from 

wastewater-treatment plant NY1 in New York State, fortified at moderate concentrations for seven analytes. ...13

12. Mean spike recoveries and percent relative standard deviations for 13 replicate matrix spikes of effluent from 

wastewater-treatment plant NY4 in New York State, fortified at low concentrations for six analytes. ..................14

13. Mean spike recoveries and percent relative standard deviations for five replicate matrix spikes of streamwater

collected upstream of the NY1 effluent discharge in New York State, fortified at low concentrations for seven 

analytes................................................................................................................................................................14

14. Mean recoveries, percent relative standard deviations, and method detection limits calculated from reagent 

water samples fortified at 0.05 μg/L and 0.2 μg/L. ..............................................................................................16

15. Mean concentrations and percent relative standard deviations calculated for ambient pharmaceuticals in 18 

replicate 1-liter sample aliquots from effluent collected at site NY3, New York State, 2009.................................17

16. Percent change in concentration for pharmaceuticals in unfortified wastewater treatment plant samples from 

NY3, New York State, and fortified effluent samples from NY4 after 15 days......................................................18

17. Pharmaceutical concentrations in field blank samples collected, 2004-09 (Excel format)....................................19

18. Pharmaceutical concentrations in samples of effluent from wastewater treatment plants in the national survey, 

2006-09 (Excel format).........................................................................................................................................20

19. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY1, New York State, 

2004-09 (Excel format).........................................................................................................................................21

20. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY2 in New York State, 

2004-09 (Excel format).........................................................................................................................................21

21. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY3, in New York State, 

2004-09 (Excel format).........................................................................................................................................21

22. Pharmaceutical concentrations in samples of streamwater collected downstream from the discharge point of 

wastewater treatment plant NY1, in New York State, 2004-09 (Excel format). ....................................................22

23. Pharmaceutical concentrations in samples of streamwater collected downstream from the discharge point of 

wastewater treatment plant NY2, in New York State, 2004-09 (Excel format). ....................................................22

24. Pharmaceutical concentrations in samples of streamwater collected downstream from the discharge point of 

wastewater treatment plant NY3, in New York State, 2004-09 (Excel format). ....................................................22

25. Pharmaceutical concentrations in samples of streamwater collected upstream from the discharge point of 

wastewater treatment plant NY1, in New York State, 2004-09 (Excel format). ....................................................27

26. Pharmaceutical concentrations in samples of streamwater collected upstream from the discharge point of 

wastewater treatment plant NY2, in New York State, 2004-09 (Excel format). ....................................................27

27. Pharmaceutical concentrations in samples of streamwater collected at two sites upstream from the discharge 

point of wastewater treatment plant NY3, in New York State, 2004-09 (Excel format).........................................27
vi

28. Pharmaceutical concentrations in samples collected from New York reservoirs, 2006-09 (Excel format). ..........28

29. Pharmaceutical concentrations in samples collected from sites below NY2 downstream site, in New York State, 

2009 (Excel format)..............................................................................................................................................28

30. Pharmaceuticals formulated by the pharmaceutical formulation facility or marketed by the owner of the facility 

discharging to wastewater treatment plant NY2 in New York State and quantified in samples of NY2 effluent or 

qualitatively identified in samples collected during 2008-09, or not identified in samples of NY2 effluent............30

31. Tentatively identified compounds in samples of effluent from wastewater treatment plant NY2, New York State, 

2004-09 (Excel format).........................................................................................................................................31

32. Pharmaceuticals formulated by the pharmaceutical formulation facility (PFF) or marketed by the PFF owner 

discharging to wastewater treatment plant (WWTP) NY3 in New York State and quantified in samples of NY3 

effluent or qualitatively identified in samples collected during 2008-09, or not identified in samples of NY3 

effluent. ................................................................................................................................................................31

33. Tentatively identified compounds in samples of effluent from wastewater treatment plant NY3, in New York 

State, 2004-09 (Excel format). .............................................................................................................................32

34. Effluent discharge data for samples collected at wastewater treatment plants NY1, N2, and NY3 discharge 

points in New York State, 2004-09 (Excel format)................................................................................................32

35. Streamflow data for samples collected from downstream from wastewater treatment plants NY1, N2, and NY3 

effluent discharge points, New York State, 2004-09 (Excel format). ....................................................................32
vii

Conversion Factors

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Volume

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

liter (L) 0.2642 gallon (gal)

Flow rate

cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s)

liter per second (L/s) 15.85 gallon per minute (gal/min) 

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

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

°F=(1.8×°C)+32

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 at 25°C).

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

per liter (μg/L).
viii

Abbreviations

CASRN CAS Registry Number®

FDA U.S. Food and Drug Administration

GC Gas chromatography

MDL Method detection limit

MS Mass spectrometry

NIH U.S. National Institutes of Health

PFF Pharmaceutical formulation facility

PMF Pharmaceutical manufacturing facility

PPF Pharmaceutical production facility

RPD Relative percent difference

RSD Relative standard deviation

SPE Solid-phase extraction

TIC Tentatively identified compounds

USGS U.S. Geological Survey

WWTP Wastewater treatment plant
Method Description, Quality Assurance,

Environmental Data, and other Information for 

Analysis of Pharmaceuticals in WastewaterTreatment-Plant Effluents, Streamwater, and 

Reservoirs, 2004-2009.

By Patrick J. Phillips, Steven G. Smith, Dana W. Kolpin, Steven D. Zaugg, Herbert T. Buxton, and Edward 

T. Furlong

Abstract 

Wastewater-treatment-plant (WWTP) effluents are a demonstrated source of 

pharmaceuticals to the environment. During 2004-09, a study was conducted to identify 

pharmaceutical compounds in effluents from WWTPs (including two that receive substantial

discharges from pharmaceutical formulation facilities), streamwater, and reservoirs. The methods 

used to determine and quantify concentrations of seven pharmaceuticals are described. In 

addition, the report includes information on pharmaceuticals formulated or potentially 

formulated at the two pharmaceutical formulation facilities that provide substantial discharge to 

two of the WWTPs, and potential limitations to these data are discussed. The analytical methods 

used to provide data on the seven pharmaceuticals (including opioids, muscle relaxants, and 

other pharmaceuticals) in filtered water samples also are described. Data are provided on method 

performance, including spike data, method detection limit results, and an estimation of precision. 

Quality-assurance data for sample collection and handling are included. Quantitative data are 

presented for the seven pharmaceuticals in water samples collected at WWTP discharge points, 

from streams, and at reservoirs. Occurrence data also are provided for 19 pharmaceuticals that 

were qualitatively identified. Flow data at selected WWTP and streams are presented.

Between 2004-09, 35-38 effluent samples were collected from each of three WWTPs in 

New York and analyzed for seven pharmaceuticals. Two WWTPs (NY2 and NY3) receive 

substantial inflows (greater than 20 percent of plant flow) from pharmaceutical formulation 

facilities (PFF) and one (NY1) receives no PFF flow. Samples of effluents from 23 WWTPs

across the United States were analyzed once for these pharmaceuticals as part of a national 

survey. Maximum pharmaceutical effluent concentrations for the national survey and NY1 

effluent samples were generally less than 1 μg/L. Four pharmaceuticals (methadone, oxycodone, 

butalbital and metaxalone) in samples of NY3 effluent had median concentrations ranging from 

3.4 to greater than 400 μg/L. Maximum concentrations of oxycodone (1,700 μg/L) and 

metaxalone (3,800 μg/L) in samples from NY3 effluent exceeded 1,000 μg/L. Three

pharmaceuticals (butalbital, carisoprodol, and oxycodone) in samples of NY2 effluent had 

median concentrations ranging from 2 to 11 μg/L. These findings suggest that current 
2

manufacturing practices at these PFFs can result in pharmaceutical concentrations from 10 to 

1,000 times higher than those typically found in WWTP effluents.

Introduction 

Over the last decade, numerous studies have documented the occurrence of 

pharmaceuticals in streams (Ashton and others, 2004; Bruchet and others, 2005; Kim and others, 

2007; and Kolpin and others, 2002) and have identified wastewater treatment plants (WWTPs) as 

a major source of pharmaceuticals to the environment (Ternes and others, 1999; Clara and 

others, 2005; Glassmeyer and others, 2005; Karthikeyan and Meyer, 2006; Vieno and others, 

2007; Chang and others, 2007, Ying and others, 2009). The long-term effects of low-level 

exposure to complex mixtures of pharmaceuticals on stream biota are poorly understood, 

although a variety of potential adverse effects have been documented at these low levels, 

including acute and chronic damage to biota (Quinn and others, 2008; Crane and others, 2006),

accumulation in tissues (Brooks and others, 2003; Paterson and Metcalfe, 2008), reproductive 

damage (Nentwig, 2007), inhibition of cell proliferation (Pomati and others, 2006), and 

behavioral changes (Stanley and others, 2007; Gaworecki and Klaine, 2008). Continued research 

to identify and quantify pharmaceuticals in susceptible environmental settings and to identify 

potential effects on the ecology in those settings is essential for the future protection of water 

quality and ecological health.

The discharges from facilities that manufacture pharmaceutical products are an underinvestigated source of pharmaceuticals to the environment; only limited data are currently (2010) 

available worldwide. Pharmaceutical manufacturing facilities (PMFs) include pharmaceutical 

production facilities (PPFs), which produce active pharmaceutical ingredients, and 

pharmaceutical formulation facilities (PFFs), which formulate and package pharmaceutical 

products (Hoerger and others, 2009). Past studies of pharmaceutical sources to the environment 

have focused on consumer use and disposal, and hospital waste (Brooks and others, 2003; 

Heberer and Feldmann, 2005; Watkinson and others, 2009). However, a study in India (Larsson 

and others, 2007) found antibiotic concentrations as high as 31,000 μg/L (micrograms per liter) 

in WWTP effluent that receives substantial discharges from several PPFs, and these discharges 

have resulted in pharmaceutical concentrations of 1,000 μg/L in nearby groundwater and surface 

water (Fick and others, 2009). Similarly, diclofenac concentrations exceeded 20 μg/L in effluent 

from a WWTP in Taiwan receiving PPF discharge (Lin and others, 2008). These concentrations 

are orders of magnitude higher than typical concentrations reported for WWTP effluents in the 

United States and Europe (generally below 1 μg/L).

This report is a companion report to Phillips and others (2010), which (1) describes the 

occurrence of 11 opioids, muscle relaxants, and other pharmaceuticals in effluents from 23 

WWTPs across the United States collected between 2006-2009, (2) compares the concentrations 

and mixtures of those pharmaceuticals in the effluents of 2 WWTPs that receive discharge from 

PFFs with pharmaceutical concentrations from another WWTP that does not receive PFF 

discharge (data collected between from 2004 to 2009), and (3) describes the persistence of these 

7 pharmaceuticals in streamwater samples collected downstream from three selected WWTPs 

from 2004 to 2009. The research detailed in this report was undertaken in cooperation with the 

U.S. Geological Survey (USGS) and the New York State Department of Environmental 

Conservation.
3

Purpose and Scope

This report documents the data and presents supporting information associated with the 

study by Phillips and others (2010). This report includes

• a description of the sampling network used in the study;

• available information on the pharmaceuticals formulated at the two PFFs that 

discharge to two WWTPs in New York State included in the study;

• a description of the analytical methods used in the study, including chemicals 

analyzed for, sample preparation, qualitative and tentative identification of 

analytes, quantitation of analytes, and method performance information; and 

• environmental data generated by the study, including quality-assurance data; 

chemical data from WWTPs, streams and reservoirs; and flow data associated 

with selected samples from WWTPs and streamwater samples.

Concentrations of seven selected pharmaceutical compounds in streamwater, reservoir 

water, and effluent from WWTPs in New York State are presented in tables and illustrations.

Concentrations of those pharmaceuticals for 23 WWTPs across the United States also are 

presented in tables and illustrations.

Sampling Network

A comprehensive listing of all sites sampled in this study is provided in table 1. Samples 

were collected from 26 WWTPs, including 23 WWTPs sampled once as part of a national survey 

and three WWTPs located in New York State that were sampled multiple times. Twenty-three

WWTPs in 12 states across the United States were sampled once during 2006-09 (four as 24-

hour flow composites and 19 as grab samples) as part of a national survey. More than half of the 

23 WWTPs in the national survey receive discharge from hospitals.

Three WWTPs in New York State (sites NY1, NY2, and NY3) were sampled 35 to 38 

times during 2004-09 (table 2). Approximately 20 percent of the total wastewater inflow to 

WWTPs NY2 and NY3 is discharge from a PFF; WWTP NY2 also receives discharge from a 

hospital. WWTP NY1 does not receive hospital or PFF discharge. More than 30 streamwater 

samples were collected within a few km (kilometers) downstream from the outfall of WWTPs 

NY1, NY2, and NY3 using standard width- and depth-integrating techniques. The distance 

downstream from the WWTP discharge points and the amount of dilution in terms of the effluent 

as a percent of streamflow for the downstream sites are given in table 3. No tributaries enter the 

streams between the effluent discharge points and the downstream sampling locations.

Site codes, USGS site numbers, and the site names for all sites sampled as part of this 

study are included in table 4. In addition to the sites discussed in the preceding paragraphs, sites 

located upstream from the three NY WWTPs were sampled for streamwater (table 4). No 

tributaries enter the stream between the sampling site on the stream above the WWTP and the 

effluent discharge sampling site for sites NY1 and NY2. At the NY3 site, a small tributary enters 

the stream between the upstream main-stem sampling location and the NY3 effluent discharge.

Because two streams join just before the NY3 effluent discharge point, both of these streams 

were sampled to represent pharmaceutical concentrations in streamwater upstream from the NY3 

effluent discharge point. Between 1 and 16 samples were collected from 10 reservoirs in New 

York State (table 4) during 2006-09. Many of these samples (16) were collected from RES01, a 

drinking water reservoir 30 km downstream of site NY2. Additional streamwater samples were 

collected downstream from or near the NY2 WWTP effluent discharge point to characterize 
4

pharmaceutical concentrations in this setting (table 4). Finally, three sites are included in table 4 

that correspond to additional sites with data from blank samples.

Table 1. Descriptions of 23 wastewater-treatment plants sampled once during 2006-09 in a national

survey of wastewater-treatment-plant effluent and three wastewater-treatment plants in New York State 

sampled multiple times during 2004-09.

[All sites except IA2, NY1, and NY4 use activated sludge for biologic treatment; site NY4 uses rotating biologic 

contactor; sites IA2 and NY1 use trickling filter. Samples from sites CA1, MD1, NY1, NY2, NY3, and VT1 were 

collected as 24 hour flow-weighed composites. A dash (-) in the column for pharmaceutical source indicates neither 

a hospital nor a pharmaceutical manufacturer discharges to the site. m3

/s, cubic meters per second] 

Site code Location

Population 

served

Pharmaceutical source:

hospital (H) or 

pharmaceutical 

manufacturer (P)

Effluent 

discharge rate

(m3/s)

National survey

AZ1 Arizona-1 500,000 H 1.0

AZ2 Arizona-2 1,000,000 H 1.4

CA1 California 4,000,000 H 20

CO1 Colorado 110,000 H 1.1

FL1 Florida 1,250,000 H 8.8

IA1 Iowa-1 25,000 H 0.22

IA2 Iowa-2 42,000 - 0.38

MD1 Maryland 1,300,000 H 7.9

MT1 Montana-1 30,000 H 0.12

NV1 Nevada 300,000 H 1.3

NY4 New York-4 800 - 0.0033

NY5 New York-5 200 - 0.0027

NY6 New York-6 1,000 - 0.013

NY7 New York-7 1,350 - 0.0088

NY8 New York-8 3,500 - 0.051

NY9 New York-9 800 H 0.011

TX1 Texas-1 1,200,000 H 3.2

TX2 Texas-2 1,400 - 0.013

TX3 Texas-3 37,000 H 3.3

VT1 Vermont-1 31,000 - 0.20

VT2 Vermont-2 7,000 H 0.044

WI1 Wisconsin-1 1,100,000 H 4.40

WI2 Wisconsin-2 330,000 H 1.80

New York sites sampled multiple times

NY1 New York-1 10,000 - 0.061

NY2 New York-2 3,000 H,P 0.031

NY3 New York-3 400 P 0.0031
5

Table 2. Number of effluent samples collected from wastewater treatment plants and streamwater 

samples collected at sites NY1, NY2, and NY3 in New York State during 2004-09, and types of 

treatment provided by each wastewater treatment plant.

Site

Number 

of effluent 

samples

Number of 

downstream 

samples

Secondary 

biological treatment Tertiary treatment Disinfection

NY1 36 35 Trickling Filter Sand filtration Chlorination/dechlorination

NY2 35 36 Two-Stage 

activated sludge 

Sand filtration Chlorination/dechlorination

NY3 38 36 Extended aeration

activated sludge

Sand/anthracite

micro-filtration

Ultraviolet

Table 3. Distance downstream and effluent dilution at three stream sampling sites in New York State, 

2004-09.

[km, kilometers; L/s, liters per second]

Site

Distance 

downstream 

(km)

Median effluent 

discharge (L/s)

Median 

streamflow 

(L/s)

Median percent of 

streamflow from 

effluent

NY1 0.01 53 330 15

NY2 1.2 30 120 24

NY3 6.1 2.8 1,500 0.17

Table 4. Sites sampled across the United States during 2004-09 (Excel format).

Information on Pharmaceuticals Formulated at PFFs

Publically available information on pharmaceuticals formulated at the PMFs is limited. Such 

information can be useful for designing studies that characterize the potential pharmaceutical 

source loadings to the environment from a PMF. Information provided in this report on 

pharmaceuticals formulated at PFFs that discharge to WWTPs NY2 and NY3 is based on the 

following sources:

(1) Direct USFDA (Food and Drug Administration) identification of selected

pharmaceuticals formulated at these sites (Suzanne Fitzpatrick, Food and Drug 

Administration, written commun., 2009),

(2) A New York State report indicating use of two pharmaceuticals at the PFF discharging to 

NY3 (New York State Department of Environmental Conservation, 2009),

(3) A web site operated by The U.S. National Institutes of Health (NIH) that provides labels 

for select pharmaceuticals, identifying the company marketing the pharmaceutical or the 

company manufacturing the pharmaceutical (Daily Med, 2009), and

(4) Manufacturers’ web sites that list the pharmaceuticals marketed by the owners of the 

PFFs (Covidien, 2009; Watson Pharmaceuticals, 2009).
6

Method Description

The method of analysis of the selected pharmaceuticals is based on a previously 

developed method for the determination of 61 compounds typically found in domestic and 

industrial wastewater (Zaugg and others, 2002). The changes to the existing method included 

identification and quantitation of seven additional analytes but did not include any change to 

extraction or other procedures. A brief explanation of the method and approach to adding 

analytes is provided here; a detailed description of the overall method is available in Zaugg and 

others (2002).

The seven additional pharmaceuticals were selected primarily because full-scan gas 

chromatography/mass spectrometry analysis of samples from sites NY1, NY2, and NY3 prior to 

this study indicated that these pharmaceuticals were commonly present as tentatively identified 

compounds in samples analyzed for organic waste indicator compounds. Several of these 

pharmaceuticals are among the most commonly prescribed medications in the United States 

(Lamb, 2009), yet limited environmental occurrence data are available for these pharmaceuticals 

in the United States. All seven target pharmaceuticals are listed in table 5; all but carisoprodol 

were analyzed for in samples collected during this study (2004-09), whereas carisoprodol was 

analyzed for in all samples collected after March 2006.

Table 5. List of seven target pharmaceuticals with chemical properties and method detection limit. [CASRN, CAS Registry Number®; Kow, octanol-water partition coefficient; mg/L, milligram per liter; μg/L, 

microgram per liter]

Analyte CASRNa Compound class

Log 

Kowb

Water 

solubility 

(mg/L)b

Method 

detection limitc

(μg/L)

Butalbital 77-26-9 Barbiturate 1.87 1,700 0.014

Carisoprodol 78-44-4 Muscle relaxant 2.36 300 0.021

Diazepam 439-14-5 Benzodiazepine

tranquilizer

2.82 50.0 0.012

Metaxalone 1665-48-1 Muscle relaxant 2.60 90.7 0.011

Methadone 76-99-3 Opioid 3.93 48.5 0.044

Oxycodone 76-42-6 Opioid 0.66 4,160 0.076

Phendimetrazine 634-03-7 Amphetamine 1.70 17,300 0.021

a

This report contains CAS Registry Numbers®, which is a Registered Trademark of the American Chemical 

Society. CAS recommends the verification of the CASRNs through CAS Client ServicesSM.

b Chemical properties from online database http://www.syrres.com/esc/physdemo.htm (accessed January 2008).

c

Method detection limits were determined from 10 reagent water samples fortified at 0.05 μg/L and 7 reagent water 

samples fortified at 0.20 μg/L.

Sample Preparation, Apparatus, Instrumentation, and Standards

One-liter samples were filtered through 0.7 μm (micrometer) glass-fiber filters prior to 

solid-phase extraction (SPE). After filtration, three surrogate compounds (table 6) were added to 

each environmental and (or) quality-control sample to monitor sample-specific method 

performance. Laboratory reagent blank and reagent set spike samples were prepared with each 
7

set of as many as 10 environmental samples. Samples were extracted by vacuum filtration 

through 500-mg (milligram) OASIS-HLB-SPE cartridges (Waters Inc., catalog number 

186000115) using a custom extraction manifold; the desired extraction flow-rate range was 25 to 

50 mL/min (milliliters per minute). (The use of trade, firm, or brand names in this paper is for 

identification purposes only and does not constitute endorsement by the USGS.) SPE Cartridges 

were eluted with dichloromethane:diethyl ether, 80:20 volume per volume. Sample extracts were 

evaporated to 0.4 mL, placed in a 1.5-mL autosampler vial. Internal standards were added, and 

the sample was held at -4o C (degrees Celsius) until instrumental analysis was performed. 

Sample extracts were analyzed using capillary gas chromatography/mass spectrometry (GC/MS, 

Agilent Technologies model 6890 GC and model 5973 MS) and operated under full scan 

conditions and using electron impact ionization at 70 eV (electron volts).

Table 6. Retention time, quantitation ion, and confirmation ions for target analytes, surrogate compounds, 

and internal standard reference compounds.

[min, minutes; m/z, mass-to-charge ratio; -- no data]

Analyte

Retention

time

(min)

Quantitation

ion

(m/z)

Confirmation

ion

(m/z)

Confirmation

ion

(m/z)

Analytes

Butalbital 30.96 168 167 181

Carisoprodol 33.53 245 158 184

Diazepam 38.70 256 283 221

Metaxalone 36.32 122 221 107

Methadone 36.13 294 72 165

Oxycodone 39.53 315 258 230

Phendimetrazine 27.74 191 51 85

Surrogates

Caffeine-d9 33.07 203 115 --

Decafluorobiphenyl 19.59 334 265 --

Fluoranthene-d10 36.31 212 106 --

Internal Standards

Acenaphthene-d10 28.64 164 162 160

Chrysene-d12 38.79 240 -- --

Perylene-d12 41.97 264 132 --

Phenanthrene-d10 32.63 188 -- --
8

The GC conditions were:

 Column: HP Ultra II (5 percent phenylmethyl silicone), 30 m (meter) x 0.25 mm 

(millimeter), 0.50 μm film thickness;

 Carrier gas: ultra high purity helium with a linear-flow velocity of 32 cm/s (centimeter per 

second);

 Injection port temperature: 290oC; 1 μL (microliter) volume;

 Split vent open 0.7 min;

 GC oven temperature program: initial temperature, 40oC, then ramp rate 4oC/min to 100oC, 

then 8o C/min to 350o C, hold time 2 min at 350o C.

The mass spectrometer conditions were: 

 Ionization energy: 70 eV,

 Operation: Full-scan from 50 to 450 atomic mass units at 1 scan/sec.

 Temperatures: source 230oC, GC/MS interface 290oC.

Metaxalone and phendimetrazine standards were obtained from Toronto Research 

Chemicals. All the remaining standards were obtained from Fisher Scientific. Purity for all 

compounds was 99 percent or better.

Qualitative and Tentative Identification of Analytes 

Detection of a target analyte was reported only if it met qualitative GC/MS criteria 

(retention time, comparison to reference standard mass spectra including ion-abundance ratios; 

see table 6). This qualitative criteria required that (1) GC retention time was within ±0.05 minute 

of that of the authentic standard, and (2) the mass spectral quantitation ion and two confirmation 

ion abundance ratios were within ±20 percent of the standard values.

Besides the seven target analytes, additional pharmaceuticals were subsequently 

identified qualitatively in at least two samples collected during 2008-09. Authentic standards 

were obtained for comparison; the qualitative criteria include confirmation of GC retention time 

and mass spectral abundance. Ions used for qualification for these additional pharmaceuticals are 

listed in table 7.

Tentatively identified compounds (TIC) were observed and are reported in this paper 

according to guidelines indicated in the U.S. Geological Survey Office of Water Quality 

Technical Memorandum 90.11 (Rickert, 1990). TICs were identified by comparing mass spectra 

collected from environmental samples to reference mass spectra in the National Institute of 

Standards and Technology NIST05a mass spectral reference library. The NIST05a library is a 

reference MS (mass spectrometry) spectral library of pure compounds collected under full scan 

mode under 70 eV electron-impact ionization conditions. A computer comparison algorithm, 

proprietary to the MS software used, was applied to each TIC spectra to identify the best fit 

candidate library spectra, followed by visual comparison of the reference and TIC. TICs 

suspected of being derived from pharmaceuticals that had a probability match factor of 70 or 

greater and which were visually confirmed by the analyst were reported.
9

Table 7. Measured retention time, quantitation ion, and confirmation ions for qualitatively identified 

compounds.

[min, minutes; m/z, mass-to-charge ratio]

Analyte

Retention

time

(min)

Quantitation

ion

(m/z)

Confirmation

ion

(m/z)

Confirmation

ion

(m/z)

2-Ethyl-2-phenylmalonamide 33.97 163 148 120

Acetaminophen 31.03 109 151 80

Bupropion 29.71 100 139 224

Chlorpheniramine 35.05 203 205 167

Codeine 38.40 299 229 162

Dihydrocodeine 38.42 301 284 286

Diltiazem 42.40 58 71 150

Fluoxetine 33.55 309 148 104

Hydrocodone 38.90 299 242 214

Meperidine 32.18 71 247 246

Meprobamate 32.54 83 144 114

Methylphenidate 32.00 84 91 150

Methocarbamol 35.18 118 109 124

o-Desmethyltramadol 35.20 58 121 249

Phenobarbital 34.67 204 232 117

Primidone 37.10 190 146 117

Temazepam 39.89 271 300 256

Tramadol 34.51 58 263 135

Verapamil 43.84 303 151 58

Quantitation of Analytes 

Target analytes that met the qualitative identification criteria were quantified using the 

injection internal standard method using a 5 to 8 point calibration curve (Zaugg and others, 

2002).

Quantifying High Concentrations

The method used in this study was initially designed to quantify environmental 

concentrations of the target analytes in the general range of 10 μg/L and less. The initial 

maximum calibration point for most compounds was 40 μg/L, with the exception of diazepam 

(4 μg/L), and metaxalone (400 μg/L).

Because concentrations exceeding the uppermost value on the calibration curve were 

consistently detected in effluents from two WWTPs (NY2 and NY3), calibration curves were 

extended during the course of the study. For samples collected after March 2009, calibration 

curves were extended to allow for quantitation over a broader range of concentrations, and 

maximum calibration points were extended to 400 μg/L for all compounds except metaxalone, 

which was extended to 4,000 μg/L. Concentrations exceeding the calibration curve were 

censored and reported as greater than (>) the concentration of the maximum calibration point.

For selected samples collected before the higher calibration standards were used, 

concentrations were quantified above the maximum calibration point using the higher calibration 
10

curves and (or) by (1) diluting samples, (2) extracting lesser amounts of sample, or (3) analysis 

of frozen archived samples. Overall, much of the data from site NY3 effluent samples were 

affected by the calibration curve dynamic range limitation with from 20 percent to 60 percent of 

samples right-censored for butalbital, metaxalone, methadone, and oxycodone. A few samples 

(less than 20 percent) were right-censored at 40 μg/L for butalbital and carisoprodol in samples 

collected from NY2 effluent.

Quantifying Low Concentrations

For samples collected before August 1, 2007, minimum calibration points were 0.4 μg/L 

for all analytes except diazepam (0.04 μg/L) and metaxalone (4 μg/L). After this time, the 

minimum calibration point was extended to 0.04 μg/L for most analytes, to 0.004 μg/L for 

diazepam, and to 0.4 μg/L for metaxalone. Some low-level concentrations are reported that are 

greater than the method detection limit (MDL) but less than the lowest point on the calibration 

curve, particularly for samples collected before August 2007. These estimated values are 

identified as such herein and were generally within 50 percent of the lowest point on the 

calibration curve.

Method Performance

This section details the method performance tests that were undertaken to insure that the 

data generated by the modified analytical method were of high quality. The assessments of 

method performance include a variety of spikes, a method detection limit study, a study to 

estimate precision, and a holding time study. The measures of method performance discussed 

below reflect (1) method performance results collected over the entire period when 

environmental samples were analyzed and (2) specific method performance evaluations made 

after the range of concentrations likely to occur was better understood.

Spikes

A variety of spike experiments were performed to characterize method performance. 

Reagent set spike samples were reagent water samples fortified with known amounts of the eight 

pharmaceuticals and processed with a set of environmental samples. The final fortification 

concentration reflects the sensitivity of each compound in the analysis. Individual reagent set

spike samples were used to evaluate set-specific method performance in the absence of sample 

matrix components. The individual reagent set spike results can be used to assess overall method 

bias and precision by aggregating individual reagent set spike samples and calculating mean 

recoveries and relative standard deviations (RSDs). Reagent set spike recoveries reflect method 

performance in the absence of coextracted sample matrix components. In order to better assess 

these contrasting matrix effects on the seven pharmaceuticals in this study, replicate samples 

from three different wastewater sources and a streamwater sample collected upstream from one 

of these wastewater discharge points were fortified with all or a select group of these 

pharmaceuticals, and recoveries were determined after correction for ambient compound 

concentrations from analysis of two or more unspiked replicates.

Reagent Set Spikes 

Reagent set spike data were divided into two periods corresponding to different spiking 

concentrations. Data on reagent set spike samples analyzed before 2009 are given in table 8, and 
11

those for 2009 are given in table 9. Spike concentrations were higher for the reagent set spikes 

analyzed before 2009; spike concentrations were decreased for analyses in 2009 to better 

correspond to concentrations typically present in samples. Results of analyses of reagent set

spike recoveries over the duration of the study indicated no temporal trends, further indicating 

method performance was stable over the course of the study. The differences between pre-2009 

and 2009 reagent set spike recoveries and RSDs are likely due to the difference in spiking levels 

and to a lesser extent the difference in the number of spikes between the two periods.

Table 8. Mean recovery and relative standard deviation of pharmaceuticals from reagent set spike 

samples analyzed before 2009.

[RSD, relative standard deviation].

Analyte

Number of 

spikes

Fortification 

concentration, in

micrograms per liter

Mean percent 

recovery

Percent 

RSD

Butalbital 54 8 82 18

Carisoprodol 54 8 113 21

Diazepam 54 0.8 96 23

Metaxalone 54 80 102 14

Methadone 54 8 70 28

Oxycodone 54 8 72 34

Phendimetrazine 54 8 86 22

Table 9. Mean recovery and relative standard deviation of pharmaceuticals from reagent set spike 

samples for 2009.

[RSD, relative standard deviation]

Analyte

Number of 

spikes

Fortification 

concentration, in

micrograms per liter

Mean percent

recovery

Percent 

RSD

Butalbital 24 0.2 124 22

Carisoprodol 24 0.2 140 27

Diazepam 24 0.2 111 17

Metaxalone 24 0.2 118 23

Methadone 24 0.2 66 25

Oxycodone 15 0.2 105 46

Phendimetrazine 19 0.2 83 21

Mean reagent set spike recoveries for both sets of reagent set spike data range from 66

percent to 140 percent, and RSDs are generally less than 30 percent. The only mean reagent set 

spike outside the 60 percent to 130 percent range is the low-concentration carisoprodol spike 

(140 percent). Only two RSDs are greater than 30 percent: RSDs for the oxycodone lowconcentration and high-concentration spikes are 34 and 46 percent, respectively.

Matrix Spikes

The four matrix spike samples include: (1) an NY3 effluent spiked at high concentrations 

(5-4,000 μg/L), (2) an NY1 effluent sample spiked at moderate (0.8-80 μg/L) concentrations, (3) 
12

an NY4 effluent sample spiked at low (0.2 μg/L) concentrations, and (4) a streamwater sample 

collected upstream from the NY1 WWTP discharge point (hereafter referred to as the NY1 

upstream sample) spiked at low–moderate concentrations (0.08-8 μg/L). The number of replicate 

samples spiked range from 5 to 13 for each matrix spike. These matrices included various 

wastewaters with a wide range of expected pharmaceutical concentrations and a streamwater 

with no effluent discharge.

NY3 Effluent Matrix Spikes

A single composite sample of NY3 effluent collected in May 2009 was divided into six 

replicate 1-L (liter) samples, and fortified with six of the seven analytes (all but diazepam) at 

high concentrations (5 to 4,000 μg/L) to assess method performance for very high analyte

concentrations in wastewater-enriched environmental samples. These samples were extracted 

and analyzed in a single analytical set. Any ambient environmental contributions of analytes to 

the matrix spike replicates were corrected for by duplicate analysis of unspiked samples. Results 

for the six effluent samples spiked with analytes are listed in table 10. For the six analytes with 

available data, mean recoveries and RSDs of analytes fortified with high concentrations in 

samples of NY3 effluent (table 10) are similar to recoveries and RSDs observed in reagent set 

spikes (tables 8, 9). All analytes for the NY3 effluent spiked samples have recoveries of 60

percent to 130 percent, and RSDs were all less than 30 percent.

Table 10. Mean spike recoveries and percent relative standard deviations for six replicate matrix spikes of 

effluent from wastewater treatment plant NY3 in New York State, fortified over a range of high 

concentrations for six analytes.

[RSD, relative standard deviation; Diazepam was not spiked in these samples so that data for this analyte is not 

available; μg/L, micrograms per liter] 

Analyte

Fortification 

concentration, in 

micrograms per liter

Mean percent 

recovery

Percent 

RSD

Butalbital 12 - 402 87 2.8

Carisoprodol 20 - 800 94 13

Metaxalone 104 - 4,000 77 11

Methadone 92 - 871 63 12

Oxycodone 24 - 804 70 11

Phendimetrazine 22 - 802 70 16

NY1 Effluent Matrix Spikes

A single composite sample of NY1 effluent collected in March 2007 was divided into 

five replicate 1-L samples and fortified with the analytes at moderate (0.8 to 80 μg/L) 

concentrations to assess method performance for moderate analyte concentrations in wastewaterenriched environmental samples. These samples were extracted and analyzed in a single 

analytical set. Any ambient environmental contributions of analytes to the matrix spike replicates 

were corrected for by duplicate analysis of unspiked samples. Results for the five effluent 

samples spiked with seven analytes are listed in table 11. 
13

Table 11. Mean spike recoveries and percent relative standard deviations for five replicate matrix spikes of 

effluent from wastewater-treatment plant NY1 in New York State, fortified at moderate concentrations 

for seven analytes.

[RSD, relative standard deviation]

Analyte

Fortification 

concentration, in 

micrograms per liter

Mean percent 

recovery

Percent 

RSD

Butalbital 8 95 7.2

Carisoprodol 8 104 6.1

Diazepam 0.8 94 4.6

Metaxalone 80 96 5.9

Methadone 8 59 27

Oxycodone 8 94 7.4

Phendimetrazine 8 66 26

Mean recoveries and RSDs of analytes fortified with moderate concentrations in samples 

of NY1 effluent (table 11) are similar to recoveries and RSDs observed for reagent set spikes 

(tables 8, 9) and those for the NY3 effluent spike samples (table 10). All but one of the mean 

recoveries are within the 60 percent to 130 percent range, and all RSDs were less than 30

percent. The only recovery outside the 60 percent to 130 percent range is methadone (59 percent; 

table 11). As was the case for NY3 effluent spikes, many of these analytes have RSDs that are 

lower in these matrix spikes than in reagent set spikes. This is attributed to the analysis of these 

samples in a single set; the reagent set spikes were analyzed in multiple sets over several years.

NY4 Effluent Matrix Spikes 

A single composite sample of NY4 effluent collected in May 2009 was divided into 13 

replicate 1-L samples and fortified with the analytes at low (0.2 μg/L) concentrations to assess

method performance for low analyte concentrations in wastewater-enriched environmental 

samples. The NY4 effluent sample was spiked so that an effluent sample would be included in 

spiking experiments from the set of 23 WWTP effluent samples in the national survey. Any 

ambient environmental contributions of analytes to the matrix spike replicates were corrected for

by triplicate analysis of unspiked samples. These 13 replicate samples were extracted in 5 

different extraction sets and then analyzed in a single analytical set.

Results for the spiked analytes are listed in Table 12. These samples were also used for a 

holding time study (see below). Data for all the analytes but phendimetrazine are available; the 

data for phendimetrazine from the NY4 effluent spike holding time experiment are not included 

because there was a significant decrease in the concentration for this analyte over the 15 day 

holding time experiment. Thus, with the exception of phendimetrazine, the aggregated results 

could also be used as a matrix spike recovery experiment.

Five of the six analytes with available data for NY4 Effluent spikes have mean percent 

recoveries within the 60 percent to 130 percent range, and all but one of the RSDs are less than 

30 percent. Recoveries for oxycodone (170 percent) are higher than the other analyte recoveries 

in this spike, but the RSD is low (8.8 percent). Only the methadone RSD exceeds 30 percent (31 

percent). For most analytes, the recoveries were higher and RSDs are similar to those for reagent 

set spikes (tables 8, 9) and other effluent matrix spikes (tables 10, 11). The high mean recovery 

for oxycodone in this spike may reflect the low spiking level used in this experiment.
14

Table 12. Mean spike recoveries and percent relative standard deviations for 13 replicate matrix spikes of 

effluent from wastewater-treatment plant NY4 in New York State, fortified at low concentrations for six 

analytes.

[RSD, relative standard deviation]

Analyte

Fortification 

concentration, in 

micrograms per liter

Mean percent 

recovery

Percent

RSD

Butalbital 0.2 120 10

Carisoprodol 0.2 99 5.1

Diazepam 0.2 110 6.5

Metaxalone 0.2 120 5.1

Methadone 0.2 91 31

Oxycodone 0.2 170 8.8

NY1 Upstream Matrix Spikes

A single composite sample of streamwater collected upstream from NY1 in March 2007 

was divided into five replicate 1-L samples, and fortified with target analytes at low (0.08-8 

μg/L) concentrations to assess method performance for low analyte concentrations in 

environmental waters with negligible wastewater content. These samples were extracted and 

analyzed in a single analytical set. Any ambient environmental contributions of analytes to the 

matrix spike replicates were corrected for by duplicate analysis of unspiked samples. Results for 

the seven samples spiked with analytes are listed in table 13.

Table 13. Mean spike recoveries and percent relative standard deviations for five replicate matrix spikes of 

streamwater collected upstream of the NY1 effluent discharge in New York State, fortified at low 

concentrations for seven analytes.

[RSD, relative standard deviation]

Analyte

Fortification 

concentration, in 

micrograms per liter

Mean 

percent 

recovery

Percent 

RSD

Butalbital 0.8 93 14

Carisoprodol 0.8 97 13

Diazepam 0.08 97 8.2

Metaxalone 8 87 8.5

Methadone 0.8 32 48

Oxycodone 0.8 57 36

Phendimetrazine 0.8 57 23

Four analytes (butalbital, carisoprodol, diazepam, and metaxalone) have mean recoveries 

of 60 percent to 130 percent, and five have RSDs less than 30 percent in the NY1 upstream 

spike. Two pharmaceuticals (oxycodone and phendimetrazine) have recoveries of 57 percent and 

RSDs of 36 percent and 23 percent, respectively. Methadone has a low recovery (32 percent) and 

high RSD (48 percent) for this spike. These mean recoveries and RSDs are somewhat lower for 
15

some analytes than the recoveries and RSDs observed for the reagent set spikes (tables 8, 9) and 

for the matrix spike samples of effluent (tables 10–12) for some analytes.

Summary of Reagent Set and Matrix Spikes

Data from the different spike experiments (two reagent set spike experiments with low 

and medium analyte concentrations, three effluent spike experiments with low, medium and high 

concentrations, and a stream spike experiment with medium concentrations) show that median 

mean recoveries for all spikes are 94 percent, and median RSDs are 15 percent. For the 14 

reagent set spikes, only the mean recovery for the low concentration (0.2 μg/L) carisoprodol 

spike (140 percent; table 9) lies outside the 60 percent to 130 percent range, and only the two 

oxycodone spikes have RSDs greater than 30 percent (low level at 46 percent and high level at 

34 percent). Of the 19 effluent spikes, two mean recoveries — methadone for the moderate 

concentration NY1 effluent spike (59 percent; table 11) and oxycodone for the low-level NY4 

effluent spike (170 percent; table 12) have mean recoveries outside the 60 percent to 130 percent

range. Only one of the 19 effluent spikes, the low concentration methadone NY4 effluent, has an 

RSD greater than 30 percent (31 percent).

The effluent spiking results show that the seven analytes have low bias and variability for 

the effluent matrix. Although the low-level reagent spikes indicate that carisoprodol may have a 

positive bias for low concentrations, the recoveries for the other reagent spikes and effluent 

samples spiked with carisoprodol range from 99 percent to 104 percent, indicating no bias. 

Results of the methadone effluent spike with middle range (8 μg/L) concentrations indicate a 

slight low bias (mean recovery of 59 percent), yet the results for the other two methadone 

effluent spikes with low (0.2 μg/L) and high (≥90 μg/L) range concentrations (63 percent and 91

percent, respectively) show no bias. The results indicate a positive bias for oxycodone at low 

concentrations (0.2 μg/L), yet the two other oxycodone effluent spikes for moderate (8 μg/L) and 

high (≥24 μg/L) concentrations have mean recoveries of 94 percent and 70 percent, respectively.

The high RSDs for reagent set spikes indicate that oxycodone concentrations may be more 

variable than those of other pharmaceuticals in this study; however the three effluent spikes for 

oxycodone all have RSDs less than 30 percent.

The streamwater spike recoveries for butalbital, carisoprodol, diazepam and metaxalone 

range from 60 percent to 130 percent, with RSDs less than 30 percent, indicating low bias and 

variability. Because of the low (32 percent) and variable (RSD of 48 percent) recovery for 

methadone stream-water spikes, stream-water data for methadone are reported only qualitatively 

(as percent detection). The low recoveries for streamwater oxycodone and phendimetrazine

spikes (both 57 percent) indicate that the concentrations of these two analytes in streamwater

may be biased low. In addition, the RSD for the oxycodone spike in streamwater is 36 percent, 

indicating a higher variability for concentrations in streamwater of this pharmaceutical than for 

the others.

Method Detection Limit 

The determination of MDLs for each pharmaceutical was conducted according to the 

procedures of the U.S. Environmental Protection Agency (2005), and MDLs are presented in 

table 14. MDLs were calculated using the following equation. 
16

MDL=S x T(n-1, 1-alpha=0.99) (1),

where

S is standard deviation of replicate analysis, in micrograms per liter, at the lowest spike 

concentration;

n is number of replicate analyses; 

and

T(n-1, 1-alpha=0.99) is Student’s t-value for the 99 percent confidence level with n-1 

degrees of freedom.

The MDLs were determined using a low-level reagent spike study that employed multiple 

experiments in order to ensure that the lowest appropriate spiking level was used to calculate 

each individual MDL. These experiments resulted in data that provide reagent set spike 

recoveries near the detection limit as well as MDLs, which are discussed together in this section.

Two fortification concentrations were used. Ten reagent water samples were fortified at 0.05 

μg/L for each compound, extracted, and analyzed. These samples were analyzed in the same 

analytical set. Seven reagent water samples were fortified at 0.2 μg/L for each analyte, extracted, 

and analyzed. These samples also served as set spikes, and were prepared and analyzed in 

different analytical sets. Details on the mean recoveries, percent RSDs, and calculated MDLs at 

both fortification concentrations are shown in table 14.

Table 14. Mean recoveries, percent relative standard deviations, and method detection limits calculated 

from reagent water samples fortified at 0.05 μg/L and 0.2 μg/L.

[RSD, relative standard deviation in percent; MDL, method detection limit; ND, not detected; --, data not calculated; 

μg/L micrograms per liter; n, number of replicates. Method detection limits values in bold correspond to those used 

as final method detection limits.]

0.05 μg/L fortification (n=10) 0.20 μg/L fortification (n=7)

Analyte

Mean 

percent 

recovery

Percent 

RSD

MDL,

in μg/L

Mean 

percent 

recovery

Percent 

RSD

MDL,

in μg/L

Butalbital 112 9 0.014 110 5.6 0.036

Carisoprodol 97 15 0.021 100 5.9 0.035

Diazepam 125 7 0.012 110 5.4 0.034

Metaxalone 99 8 0.011 110 4.4 0.029

Methadone 57 13 -- 74 10 0.044

Oxycodone ND -- -- 94 14 0.076

Phendimetrazine 52 28 0.021 69 24 0.098

Five of the seven analytes (butalbital, carisoprodol, diazepam, metaxalone, and 

phendimetrazine) were reliably detected in the 0.05 μg/L fortification samples, and the MDLs at 

this fortification were used as MDLs in the study (table 14). The remaining two analytes

(methadone and oxycodone) were detectable at 0.20 μg/L (table 14). Although a mean recovery 

could be calculated for methadone in the 0.05-μg/L fortification level, methadone was detected 

in only 7 of the 10 samples fortified at 0.05 μg/L, so the results of the 0.20-μg/L fortification 

level were used for methadone. Mean recoveries and RSDs of the five analytes reliably detected 
17

at the 0.05-μg/L fortification level are comparable to the mean recoveries and RSDs at the 0.2 

μg/L fortification and in the range typical for reagent set spikes (see tables 8, 9). All mean 

recoveries and RSDs at the 0.2-μg/L fortification level are comparable to mean recoveries and 

RSDs in the reagent set spike results (tables 8, 9). The spiking concentrations used for MDL 

determinations were appropriate, because the spiking levels are within 1 to 5 times the MDLs.

Estimation of Precision 

In order to better understand precision in the analysis of environmental samples, 18 

replicates of a homogeneous sample of NY3 effluent were analyzed, and method precision was 

calculated. The replicates were prepared for analysis in five different preparation sets, but 

instrumental analysis was conducted as a single set. These replicates also were used for a holding

time study (see below), and thus, the calculated precision better incorporates sources of variation 

associated with different preparation sets. The results of this experiment are shown in table 15.

Because these data represent the environmental concentrations in NY3 effluent at the time of 

sample collection, all analytes were not present. Most analytes (5 of 7) were detected in the 

sample of NY3 effluent, allowing for the assessment of precision for most of the analytes

included in the study; the RSDs for these five compounds range from 5.1 percent to 21 percent.

This precision is comparable to other estimates of precision for environmental samples made for 

pharmaceuticals and wastewater indicator compounds included in previous studies (Glassmeyer 

and others, 2005).

Table 15. Mean concentrations and percent relative standard deviations calculated for ambient 

pharmaceuticals in 18 replicate 1-liter sample aliquots from effluent collected at site NY3, New York 

State, 2009.

[RSD, relative standard deviation, in percent.]

Analyte

Mean 

concentration, 

in micrograms 

per liter

Percent 

RSD

Butalbital 1.6 5.2

Metaxalone 4.23 5.1

Methadone 71.7 11

Oxycodone 3.7 21

Phendimetrazine 1.79 6.4

Holding Time Study

The method of analysis used in this study was based on a recommended holding time 

(Zaugg and others, 2002) of up to 14 days for filtered water samples. Since these samples were 

comprised of treated wastewater, however, separate holding time studies were conducted in order 

to assess whether the maximum recommended 14-day holding time would introduce systematic 

low bias into the results as a result of potential degradation of the seven pharmaceuticals of 

interest. Two studies were conducted using multiple aliquots of samples collected at the NY3 

and NY4 WWTP sites. The NY4 sample aliquots were fortified with the seven analytes and these 

aliquots analyzed over a 14-day period. The NY3 replicate sample aliquots were not fortified and 
18

were also analyzed over a 14-day period. Two experiments were conducted to include an 

assessment of long holding times for a range of wastewater-treatment matrices, as the NY3 

effluent was from an activated sludge wastewater plant, and the NY4 effluent was from a 

rotating biologic contactor wastewater plant. These data were useful for ensuring that holding 

time information was available for all seven analytes included in the study, and for indicating

whether results would be different for unfortified samples (NY3) and fortified samples (NY4).

Eighteen NY3 replicate effluent samples were analyzed to determine compound 

degradation in sample matrix with respect to time. None of these samples were fortified, because 

they contained high ambient environmental concentrations of most (five) of the seven analytes. 

Three samples were extracted within 24 hours of sampling. Three samples were extracted 3 days 

from collection, then 3 more samples were extracted on days 5, 7, 11, and 15. Linear regression 

analysis of concentration versus hold time was performed to calculate a degradation rate. This 

rate was used to determine the percentage of analyte lost to degradation in 15 days. The results of 

the holding time study for these unfortified samples are shown in table 16.

Table 16. Percent change in concentration for pharmaceuticals in unfortified wastewater treatment plant 

samples from NY3, New York State, and fortified effluent samples from NY4 after 15 days.

[Negative results indicate a decrease, and positive results indicate an increase in concentration; ND, no data]

Analyte

Percent change in 

concentration in 

unfortified

NY3 effluent

Percent change in 

concentration in 

fortified

NY4 effluent

Butalbital -1.7 1.3

Carisoprodol ND -7.3

Diazepam ND -3.6

Metaxalone -1.0 -3.9

Methadone 0.3 -6.9

Oxycodone -7.3 -5.8

Phendimetrazine 1.2 -45

Sixteen NY4 replicate effluent samples were studied to determine compound degradation in 

sample matrix with respect to time. Thirteen 1-L replicate samples were fortified in the field at 

0.2 μg/L for all seven target pharmaceuticals at the time of collection. Three additional samples 

were collected but not spiked. The three unspiked samples and three spiked samples were 

extracted within 24 hours of sampling. Three samples were extracted three days from collection 

and three more seven days from collection. Two samples were extracted 11 days from collection 

and two more were extracted 15 days from collection. Linear regression analysis of 

concentration versus hold time was performed to determine a degradation rate for each 

pharmaceutical. This rate was used to determine the percent of analyte lost to degradation in 15 

days. The rates for all analytes are shown in table 16.

For both the NY3 and NY4 holding time experiments, four pharmaceuticals (butalbital, 

methadone, oxycodone, and metaxalone) had small (less than 8 percent) changes in 

concentrations over the 15 days (table 16). Two other pharmaceuticals, detected only in the NY4 

effluent (carisoprodol and diazepam) had small (less than 8 percent) decreases in concentrations 

after 15 days (table 16). Phendimetrazine had slight increases (1.2 percent) in concentrations in 

NY3 effluent samples but large (45 percent) decreases in concentrations in NY4 effluent spike at 
19

15 days. The lower concentrations of phendimetrazine in the NY4 effluent spike indicate that 

this sample matrix may result in degradation of these analytes in samples over 15 days. Overall, 

for most of the target pharmaceuticals, there was little indication of positive or negative bias over 

15 days, but some effluent matrices could result in a decrease in concentrations for 

phendimetrazine over a 15-day holding time. The median holding time for the environmental 

samples included in the study was 8 days, and the holding time for 90 percent of the samples did 

not exceed 15 days. Thus, the combination of small changes in concentrations for most analytes 

and the low holding times for most samples indicate that holding time between sample collection 

and extraction did not greatly affect pharmaceutical concentrations reported in this study.

Environmental Data

Quality-assurance and environmental data collected over the course of this study are 

described in the following sections.

Quality-Assurance Data

Blank and replicate data were collected in the field as part of quality-assurance data.

Blank Data

Sixty-nine field blanks were collected and analyzed during the study; 22 were collected 

prior to March 2006 and were analyzed for six of the seven analytes (all but carisoprodol), and 

47 collected after March 2006 were analyzed for all seven analytes (table 17). Field blanks were 

prepared from laboratory-grade organic-free water and were processed and handled using the 

same methods WWTP effluent and streamwater samples.

Table 17. Pharmaceutical concentrations in field blank samples collected, 2004-09 (Excel format).

Three analytes were detected in field blanks: butalbital (two blanks ranging from 0.045 to 

0.051 μg/L), oxycodone (two blanks, ranging from 0.15 to 0.73 μg/L), and metaxalone (seven

blanks ranging from 0.068 to 1.0 μg/L). Detections in blanks were associated with effluent 

samples containing high pharmaceutical concentrations (>100 μg/L) and were attributed to the

carryover of high concentrations to later samples in the same sample set. Concentrations in 

environmental samples within 10 times the concentrations in blanks which were collected during 

the same week were censored to a non-detection. Metaxalone blank contamination occurred in 

20 percent of method blanks, therefore metaxalone concentrations below 3 μg/L (10 times the 

90th percentile of concentrations in field blanks) were censored to a non-detection.

Replicate Data

Data on replicate samples are given in the data tables in the following section, and are 

listed just after the associated environmental sample. Analyses of 36 replicate samples yielded 85 

paired-replicate detections of analytes, and 6 unpaired replicate detections (a detection in only 

one of the paired samples). All but one of the unpaired detections occurred for concentrations 

less than 0.2 μg/L. Median relative percent differences (RPDs) were similar among analytes, 

ranging from 3.9 percent for metaxalone to 13 percent for oxycodone. RPDs were somewhat 
20

greater for comparisons of low concentrations (9.9 percent for concentrations less than 0.2 μg/L) 

compared to comparisons of high concentrations (4.3 percent for concentrations > 10 μg/L).

Environmental Data for Pharmaceuticals in Wastewater-Treatment Plants, and in 

Streamwater and Reservoir Water

The following sections give information on the environmental data collected at the 

various WWTPs, streams, and reservoirs during this study.

Concentrations in Samples from National Survey of Wastewater-Treatment-Plant Effluent

Concentrations of pharmaceuticals in samples collected from the national survey of 

wastewater-treatment-plant effluent are listed in table 18. Five pharmaceuticals were detected in 

at least one effluent sample collected from the 23 WWTPs included in the national survey (fig.

1). Three pharmaceuticals (butalbital, carisoprodol, and oxycodone) were detected in more than

40 percent of these samples. Maximum concentrations ranged from less than 0.1 (diazepam) to 

0.74 (butalbital) μg/L. Metaxalone and phendimetrazine were not detected in these effluent 

samples (table 18). Total pharmaceutical concentrations (equal to the sum of detected 

concentrations of all seven analytes for each sample) in samples from the 15 WWTPs that 

receive discharge from a hospital facility and the median total pharmaceutical concentrations in 

samples from the eight WWTPs without hospital discharge are given in figure 2.

Table 18. Pharmaceutical concentrations in samples of effluent from wastewater treatment plants in the 

national survey, 2006-09 (Excel format).

Figure 1. Concentrations of seven pharmaceutical compounds analyzed for in effluent from 23 

wastewater treatment plants across the United States during 2006-09.

0.1

1

10

C

O

N

CEN

T

R

ATIO

N,

IN

MIC

R

O

G

R

A

MS

PER LITER

Metha

done

Oxycodone

B

utalbital

Metaxalone

C

arisoprodol

Diaz

e

pa

m

P

he

ndimetrazine

43

8.7

83

0

13

56

0.01

0

Explanation

83

Percent of samples

with a detection

Maximum

concentration

Method detection

limit

Percentile

90

75

25

10

50
21

Figure 2. Total concentration of seven pharmaceutical compounds detected in effluent from wastewater 

treatment plants (WWTPs) (A) in individual samples from 23 plants across the United States 2006-09, 

and (B) in multiple samples from NY1, NY2, and NY3 in New York State, 2004-09.

[NH, WWTPs that do not receive discharges from hospitals; H, WWTPs that receive discharges from hospitals. Site 

NY1 does not receive discharge from a hospital or a PFF (pharmaceutical formulation facility). Site NY2 receives 

discharge from a hospital and approximately 20% of its discharge from a PFF. Site NY3 receives approximately 

20% of its discharge from a PFF, but does not receive discharge from a hospital. For sites NY1, NY2, and NY3, 

only those samples with determinations for all seven analytes are included in the total concentration calculation.]

Concentrations in Effluent Samples from Wastewater-Treatment Plants NY1, NY2 and NY3

Concentrations of pharmaceuticals in samples collected from NY1 effluent are listed in 

table 19. Data on samples collected from NY2 effluent are listed in table 20, and data for 

samples collected from NY3 effluent are listed in table 21.

Table 19. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY1, New 

York State, 2004-09 (Excel format).

Table 20. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY2 in 

New York State, 2004-09 (Excel format).

Table 21. Pharmaceutical concentrations in samples of effluent from wastewater treatment plant NY3, in 

New York State, 2004-09 (Excel format).

T

OTAL C

O

N

CEN

T

R

ATIO

N, IN

MIC

R

O

G

R

A

MS

PER LITER

0.01

0.1

1

10

100

1,000

NY1 NY2 NY3

Site Type Site Name

A. Individual

Samples from

23 WWTPs

across the US

NH H

B. Multiple Samples

from WWTPs NY1,

NY2, and NY3

Explanation

Maximum

concentration Percentile

90

75

25

10

50

Individual concentrations plotted

for categories with less than 12 samples.
22

Median concentrations of the five pharmaceuticals (butalbital, metaxalone, methadone, 

oxycodone, and phendimetrazine) most commonly detected in samples of NY3 effluent ranged 

from 0.5 to more than 400 μg/L; median concentrations of the four pharmaceuticals (butalbital, 

carisoprodol, diazepam, and oxycodone) most commonly detected in samples of NY2 effluent 

ranged from 0.74 to 11 μg/L (fig. 3). By contrast, median concentrations for the two 

pharmaceuticals (butalbital and oxycodone) most commonly detected in samples of NY1 effluent 

ranged from 0.10 to 0.19 μg/L (fig. 3). Maximum concentrations of oxycodone and metaxalone 

in samples of NY3 effluent were 1,700 and 3,800 μg/L, respectively, and maximum 

concentrations of three other pharmaceuticals (butalbital, methadone, and phendimetrazine) 

ranged from more than 40 to more than 400 μg/L. Two pharmaceuticals (butalbital and 

carisoprodol) had maximum concentrations greater than 40 μg/L in samples of NY2 effluent.

Total concentrations of pharmaceuticals in samples of NY1, NY2, and NY3 effluent are given in 

figure 2.

The temporal variations in concentrations of carisoprodol and butalbital in samples of 

effluent from WWTP NY2 collected during 2004-09 are shown in figure 4. The temporal 

variations in concentrations of butalbital, oxycodone, metaxalone, and methadone in samples of 

effluent from WWTP NY3 collected during 2004-09 are shown in figure 5.

Concentrations in Samples of Streamwater Collected Downstream from WWTP Discharge Points 

of NY1, NY2, and NY3

Concentration data of pharmaceuticals in streamwater samples collected downstream 

from WWTP NY1 are listed in table 22. Concentration data of pharmaceuticals in streamwater 

samples collected downstream from WWTP NY2 are listed in table 23. Concentration data of 

pharmaceuticals in streamwater samples collected downstream from WWTP NY3 are listed in 

table 24.

Table 22. Pharmaceutical concentrations in samples of streamwater collected downstream from the 

discharge point of wastewater treatment plant NY1, in New York State, 2004-09 (Excel format).

Table 23. Pharmaceutical concentrations in samples of streamwater collected downstream from the 

discharge point of wastewater treatment plant NY2, in New York State, 2004-09 (Excel format).

Table 24. Pharmaceutical concentrations in samples of streamwater collected downstream from the 

discharge point of wastewater treatment plant NY3, in New York State, 2004-09 (Excel format).

The distribution of concentrations of each pharmaceutical in samples collected 

downstream from the discharge points of WWTPs NY1, NY2, and NY3 are shown in figure 6. 

The relation between the ratio of concentrations of butalbital and carisoprodol in streamwater 

collected downstream from the effluent discharge point to concentrations in NY2 effluent as a

function of the percentage of streamflow consisting of NY2 effluent in samples collected 
23

downstream from NY2 is shown in figure 7 and provides a general indication of the combined 

effect of source concentrations and dilution on pharmaceutical concentrations in streamwater 

collected downstream from NY2. The temporal variations in concentrations of carisoprodol and 

butalbital in samples collected during 2004-09 downstream from the effluent discharge point of 

WWTP NY2 are shown in figure 4.

Figure 3. Concentrations of seven pharmaceuticals in samples of effluent from wastewater treatment 

plants (WWTPs) NY1, NY2, and NY3, New York State, during 2004-09.

[Site NY1 does not receive discharge from a hospital or a PFF (pharmaceutical formulation facility). Site NY2 

receives discharge from a hospital and approximately 20% of its discharge from a PFF. Site NY3 receives 

approximately 20% of its discharge from a PFF, but does not receive discharge from a hospital. Numbers of samples 

for each site are indicated next to the site name. Twenty four (24) samples were analyzed for carisoprodol at each 

site. Boxplots for pharmaceuticals with censoring in more than 25% of the samples (including methadone, 

oxycodone and metaxalone in NY3 samples) were denoted by a boxplot truncated at the upper end with a bar.]

Denotes censoring

level for concentrations

above highest point

on calibration curve.

Maximum concentrations

that are censored

Quantified concentrations

above 40 mg/L

(micrograms per liter)

or 400 mg/L (for metaxalone).

Maximum concentrations that

are not censored

15 75

78

0

NY2 (n=35)

91

97 100

100

8.6

2.9

10,000

C

ONCENTRATION,

IN MICRO

GRA

MS PER LITER

100

10

0.1

1

1,000

0.01

Methadone

Oxycodone

Butalbital

Metaxalone

Carisoprodol

Diazepam

Phendimetrazine

NY1 (n=36)

Methadone

Oxycodone

Butalbital

Metaxalone

Carisoprodol

Diazepam

Phendimetrazine

100

7.7 18

NY3 (n=38)

100

100

Methadone

Oxycodone

Butalbital

Metaxalone

Carisoprodol

Diazepam

Phendimetrazine 68

0 0 0 0

Explanation

83

Percent of samples

with a detection

Maximum

concentration

Method detection

limit

Percentile

90

75

25

10

50

100
24

Figure 4. Concentrations of carisoprodol and butalbital in samples collected (A) from NY2 effluent, (B) 

from the NY2 effluent discharge point, and (C) at the reservoir site 30 kilometers downstream from the 

NY2 site in New York State, 2004-09.

Carisoprodol

Butalbital

B. NY2 DOWNSTREAM

C

O

N

CENTR

ATIO

N,

IN

MIC

R

O

G

R

A

MS PER LITER

100

10

0.1

1

0.01

C

O

N

CENTR

ATIO

N,

IN

MIC

R

O

G

R

A

MS PER LITER

100

10

0.1

1

0.01

C

O

N

CENTR

ATIO

N,

IN

MIC

R

O

G

R

A

MS PER LITER

0.1

0.01

1

DATE

2004 2005 2006 2007 2008 2009 2010

C. RESERVOIR 30km BELOW NY2 EFFLUENT

Carisoprodol

Butalbital

Carisoprodol

Butalbital

Non-detection

Explanation

Concentration exceeded uppermost

calibration point of 40 mg/L

(micrograms per liter)

A. NY2 EFFLUENT

km Kilometers
25

Figure 5. Concentrations of (A) oxycodone and butalbital, and (B) metaxalone and methadone in samples 

from NY3 effluent, 2004-09.

A. NY3 EFFLUENT

Oxycodone

Butalbital

Metaxalone

Methadone

DATE

2004 2005 2006 2007 2008 2009 2010

100

10

0.1

1

1,000

10,000

C

O

N

CEN

T

R

ATIO

N,

IN

MIC

R

O

G

R

A

MS

PER LITER

100

10

0.1

1

1,000

10,000

C

O

N

CEN

T

R

ATIO

N,

IN

MIC

R

O

G

R

A

MS

PER LITER

B. NY3 EFFLUENT

Explanation

Concentration exceeded uppermost

calibration point of Quantified concentrations

above 40 mg/L (micrograms per liter ) or 400 mg/L (for metaxalone).
26

Figure 6. Concentrations of seven pharmaceuticals in samples collected downstream from the effluent 

discharge points of wastewater treatment plants NY1, NY2, and NY3 in New York State during 2004-

09.

(Numbers of samples for each site are indicated next to the site name. Twenty-five samples collected downstream 

from the NY1 effluent discharge point were analyzed for carisoprodol, and 26 samples collected downstream from 

the NY2 and NY3 effluent discharge points were analyzed for carisoprodol.)

A. NY1 (n=35)

B. NY2 (n=36)

92

0

100

C

O

N

CENTR

ATIO

N,

IN

MIC

R

O

G

R

A

MS PER LITER

100

10

0.1

1

0.01

2.8

11

50 19

C. NY3 (n=36)

0

0

8.6 34

8.0

0 0

97

83

2.3

0 0

*

C

O

N

CENTR

ATIO

N,

IN

MIC

R

O

G

R

A

MS PER LITER

100

10

0.1

1

0.01

Metha

done

Oxycodone

B

utalbital

Metaxalone

C

arisoprodol

Diaze

pa

m

P

he

ndimetrazine

Metha

done

Oxycodone

B

utalbital

Metaxalone

C

arisoprodol

Diaze

pa

m

P

he

ndimetrazine

*

36

*

Methadone cocentrations were

not quantified due to low and (or)

inconsistent recoveries in streamwater spikes.

Explanation

83

Percent of samples

with a detection

Maximum

concentration

Method detection

limit

Percentile

90

75

25

10

50

0

*
27

Figure 7. Ratio of the concentrations of butalbital and carisoprodol in streamwater downstream from NY2 

effluent discharge point to the concentrations of the pharmaceutical in NY2 effluent as a function of the 

percentage of streamflow consisting of wastewater treatment plant NY2 effluent, 2004-09.

[<, less than; r refers to Spearman non-parametric correlation; p, probability value]

Concentrations in Samples of Streamwater Collected Upstream from WWTP NY1, NY2, and NY3 

Discharge Points

Concentration data for pharmaceuticals in samples of streamwater collected upstream 

from the WWTP NY1 effluent discharge point are listed in table 25. Concentrations of 

pharmaceuticals in streamwater samples collected upstream from the WWTP NY2 effluent 

discharge point are listed in table 26, and concentrations of pharmaceuticals in samples of 

streamwater collected from the two sites upstream from the WWTP NY3 effluent discharge 

point are listed in table 27.

Table 25. Pharmaceutical concentrations in samples of streamwater collected upstream from the discharge 

point of wastewater treatment plant NY1, in New York State, 2004-09 (Excel format).

Table 26. Pharmaceutical concentrations in samples of streamwater collected upstream from the discharge 

point of wastewater treatment plant NY2, in New York State, 2004-09 (Excel format).

Table 27. Pharmaceutical concentrations in samples of streamwater collected at two sites upstream from 

the discharge point of wastewater treatment plant NY3, in New York State, 2004-09 (Excel format).

PERCENT OF STREAMFLOW THAT IS EFFLUENT

FROM WASTEWATER-TREATMENT PLANT NY2

0.0

0.2

0.4

0.6

0.8

1.0

RATIO

OF CO

N

CENT

RATIO

N

DOWN

S

T

REA

M

OF NY

2

T

O

CO

N

CENT

RATIO

N IN

NY

2 EFFLUENT

Butalbital (n=33)

r= 0.81, p<.05

Carisoprodol (n=32)

r=0.62, p<.05

0 20 40 60 80 100

1.2

1.4 Explanation
28

Only 3 pharmaceuticals included in this study (oxycodone, butalbital and metaxalone) 

were detected in samples collected in samples of streamwater collected upstream from the NY1, 

NY2, and NY3 effluent discharge points. Oxycodone was detected in 1 of 25 samples collected 

upstream from WWTP NY1 (0.26 μg/L). No other pharmaceutical was detected in samples 

collected upstream from WWTP NY1 (table 25). Butalbital was detected in 8 of 27 samples 

collected upstream from WWTP NY2; the maximum concentration is 0.069 μg/L. No other 

pharmaceutical was detected in 27 samples (17 samples for carisoprodol) collected upstream 

from WWTP NY2 (table 26). Oxycodone was detected in one sample (0.30 μg/L), butalbital was 

detected in 10 of 53 samples, and metaxalone was detected in 2 of 53 samples collected upstream 

from WWTP NY3 (table 27). Maximum concentrations ranged from 0.30 μg/L for oxycodone to 

1.3 and 4.2 μg/L for butalbital and metaxalone, respectively. All but one butalbital detection in 

samples collected upstream from the WWTP NY3 effluent discharge point were less than 0.2 

μg/L. No other pharmaceuticals were detected in 53 samples (30 samples for carisoprodol) 

collected upstream from WWTP NY3 (table 27).

Concentrations in Samples collected from Reservoirs and Additional Streams Downstream from 

NY2 Effluent Discharge Point

Concentration data for pharmaceuticals in reservoir samples can be found in table 28. 

Data for two sites, TD1 and TD2, that are located 1.2 miles (2.1 km) and 3.9 miles (6.6 km) 

downstream of the stream site where samples are collected below the NY2 effluent are found in 

table 29. In addition, data for site TD3, which is located on a site upstream of TD2 that does not 

receive any discharge from site NY2, can also be found in table 29. All the New York WWTP 

sites are located upstream of a New York Reservoir; sites NY1, NY2, and NY4-NY7 discharge 

to streams that are upstream of the RES01 site, site NY9 discharges to a stream that is upstream 

of the RES08 site, and sites NY3 and NY8 discharge to streams that are upstream of the RES09 

site.

Table 28. Pharmaceutical concentrations in samples collected from New York reservoirs, 2006-09 (Excel 

format).

Table 29. Pharmaceutical concentrations in samples collected from sites below NY2 downstream site, in 

New York State, 2009 (Excel format).

With the exception of one reservoir (RES01), none of the pharmaceuticals were detected 

in the reservoir samples. Two pharmaceuticals (butalbital and carisoprodol) were detected in 

samples from RES01 (table 28), but no other pharmaceuticals included in the study were 

detected in samples from the RES01. Butalbital was detected in 8 of 16 samples from RES01, 

with a maximum concentration of 0.062 μg/L, but was not detected in 30 samples from 9 other 

reservoirs. (Replicate samples are not included in any calculations of percent detections in 

samples). Carisoprodol was detected in 9 of 15 samples from RES01 at a maximum 

concentration of 0.19 μg/L and was not detected in the 28 samples from 9 other reservoirs. The 

temporal trends in carisoprodol and butalbital at the RES01 site are shown in figure 4. Butalbital, 
29

carisoprodol, and diazepam were detected in most samples collected from sites TD1 and TD2 

(table 29) but were not detected in samples from TD3.

Data on Qualitatively and Tentatively Identified Compounds

Ten additional pharmaceuticals or pharmaceutical degradates were qualitatively 

identified using authentic standards in at least two samples of the NY2 effluent collected during 

2008-09 are listed in table 30. The pharmaceuticals quantified in this study in samples of NY2 

effluent, along with an indication of the pharmaceuticals that are formulated by the PFF or 

marketed by the owner of the PFF that discharges to WWTP NY2 also are given in table 30.

Additional pharmaceuticals that were tentatively identified in NY2 effluent samples are listed in 

table 31.

Eleven additional pharmaceuticals or pharmaceutical degradates that were qualitatively 

identified using authentic standards in at least two samples of effluent collected from NY3 

during 2008-09 are listed in table 32. The pharmaceuticals quantified in this study in samples of 

NY3 effluent, along with an indication of the pharmaceuticals that are formulated by the PFF or 

marketed by the owner of the PFF that discharges to WWTP NY3 also are given in table 32.

Additional pharmaceuticals that were tentatively identified in NY3 effluent samples are listed in 

table 33.
30

Table 30. Pharmaceuticals formulated by the pharmaceutical formulation facility or marketed by the owner 

of the facility discharging to wastewater treatment plant NY2 in New York State and quantified in 

samples of NY2 effluent or qualitatively identified in samples collected during 2008-09, or not identified 

in samples of NY2 effluent.

[Compounds with “na” for source were not identified as pharmaceutical products formulated at the pharmaceutical 

formulation facility, but were included because they were qualitatively identified and may represent a degradate of a 

pharmaceutical formulated at the facility. N indicates identified as manufactured at the facility or distributed by the 

corporation owning the facility (Daily Med, 2009); M, indicates distributed by the corporation owning the facility 

(Watson Pharmaceuticals, 2009); F, indicates formulated at the facility (Suzanne Fitzpatrick, Food and Drug 

Administration, written commun., 2009); na, not applicable]

Analyte CASRNa

Source 

indicating 

production or 

marketing Compound type/use

Pharmaceuticals quantified in this study

Butalbital 77-26-9 N,M Barbiturate

Carisoprodol 78-44-4 M Muscle relaxant

Diazepam 439-14-15 N,M Benzodiazepine

Oxycodone 76-42-6 F,N,M Opioid

Pharmaceuticals qualitatively identified in samples using a standard, but not quantifiedb

2-Ethyl-2-phenylmalonamide 7206-76-0 na Primidone degradate

Bupropion 34841-39-9 F,N,M Antidepressant

Diltiazem 42399-41-7 N,M Calcium channel blocker

Hydrocodone 125-29-1 N,M Opioid

Meprobamate 57-53-4 N,M Antianxiety, carisoprodol degradate

Methocarbamol 532-03-6 N,M Muscle relaxant

Methylphenidate 113-45-1 N,M Psychostimulant (ritalin)

Phenobarbital 50-06-6 na Metabolite of primidone

Primidone 125-33-7 N,M Antiepileptic

Verapamil 52-53-9 N,M Calcium channel blocker

Pharmaceuticals identified as formulated at the site, but not identified in effluent samples

Acetaminophen 103-90-2 F Analgesic

Anagrelide 68475-42-3 F Platelet reducing agent

Colchicine 64-86-8 F Rheumatic treatment

Gabapentin 60142-96-3 F Gamma-aminobutyric acid analog

Hydrochlorothiazide 58-93-5 F Thiazide diuretic

Ibuprofen 15687-27-1 F Non-steroidal anti-inflammatory

Meperidine 57-42-1 F Opioid

Metformin 657-24-9 F Anti-diabetic

Quinidine 56-54-2 F Antiarrhythmic

Sulindac 38194-50-2 F Non-steroidal anti-inflammatory

Trazodone 19794-93-5 F Piperazine antidepressant

a CAS Registry Numbers® is a Registered Trademark of the American Chemical Society. CAS recommends the 

verification of the CASRNs through CAS Client ServicesSM.

b Compound qualitatively identified using criteria given in table 7 for samples collected between 2008-09.
31

Table 31. Tentatively identified compounds in samples of effluent from wastewater treatment plant NY2, 

New York State, 2004-09 (Excel format).

Table 32. Pharmaceuticals formulated by the pharmaceutical formulation facility (PFF) or marketed by the 

PFF owner discharging to wastewater treatment plant (WWTP) NY3 in New York State and quantified 

in samples of NY3 effluent or qualitatively identified in samples collected during 2008-09, or not 

identified in samples of NY3 effluent.

[Compounds with “na” for source were not identified as pharmaceutical products formulated at the pharmaceutical 

formulation facility, but were included because they were qualitatively identified and may represent a degradate of a

pharmaceutical formulated at the facility. N indicates identified as manufactured at the facility or distributed by the 

corporation owning the facility (Daily Med, 2009); M, indicates distributed by the corporation owning the facility 

(Covidien Pharmaceuticals, 2009); F, indicates formulated at the facility (Suzanne Fitzpatrick, Food and Drug 

Administration, written commun., 2009); S, identified as formulated at the PFF by New York State FAIR report 

New York State Department of Environmental Conservation, 2009; na, not applicable]

Analyte CASRNa

Source 

indicating 

Production or 

marketing Compound type/use

Pharmaceuticals quantified in this study

Butalbital 77-26-9 N,M Barbiturate

Metaxalone 1665-48-1 S,N Muscle relaxant

Methadone 76-99-3 F,N,M Opioid

Oxycodone 76-42-6 N,M Opioid

Phendimetrazine 634-03-7 N Anorectic

Pharmaceuticals qualitatively identified in samples using a standard, but not quantifiedb

Acetaminophen 103-90-2 F,S,N,M Analgesic

Chlorpheniramine 132-22-9 N,M Antihistamine

Codeine 76-57-3 F,N,M Opioid

Dihydrocodeine 125-58-0 na Opioid and opioid degradate

Fluoxetine 54910-89-3 F,N,M SSRI antidepressant

Hydrocodone 125-29-1 F,N,M Opioid

Meperidine 57-42-1 N,M Opioid

Methylphenidate 113-45-1 N,M Psychostimulant (ritalin)

O-Desmethyltramadol 73986-53-5 na Tramadol degradate

Temazepam 846-50-4 F,N,M Benzodiazepine 

Tramadol 27203-92-5 F,N,M Opioid

Pharmaceuticals identified as formulated at site, but not identified in samples

Cocaine 50-36-2 M Dopamine reuptake inhibitor

Dextroamphetamine 51-64-9 F Amphetamine

Morphine 57-27-2 F Opioid a CAS Registry Numbers® is a Registered Trademark of the American Chemical Society. CAS recommends the 

verification of the CASRNs through CAS Client ServicesSM.

b Compound qualitatively identified using criteria given in table 7 for samples collected between 2008-09.
32

Table 33. Tentatively identified compounds in samples of effluent from wastewater treatment plant NY3, in 

New York State, 2004-09 (Excel format).

Flow Data for Selected WWTP Effluent Samples and Streamwater Samples

WWTP Effluent discharge data for the dates that effluent samples were collected from 

NY1, NY2, and NY3 are provided in table 34. Streamflows measured at the time streamwater 

samples were collected from the sites downstream from NY1, NY2 and NY3 effluent discharge 

points are provided in table 35.

Table 34. Effluent discharge data for samples collected at wastewater treatment plants NY1, N2, and NY3 

discharge points in New York State, 2004-09 (Excel format).

Table 35. Streamflow data for samples collected from downstream from wastewater treatment plants NY1, 

N2, and NY3 effluent discharge points, New York State, 2004-09 (Excel format).

Summary

Wastewater-treatment-plant effluents are a demonstrated source of pharmaceuticals to the 

environment. This report details the methods used to conduct a study to identify concentrations 

of seven pharmaceuticals in effluents from 26 WWTPs across the Nation, as well as streamwater

and reservoirs. This report includes information on pharmaceuticals used or potentially used at 

the two pharmaceutical formulation facilities (PFFs) that provide substantial discharge to two of 

the WWTPs. The methods used to determine and quantify concentrations of seven 

pharmaceuticals (including opioids, muscle relaxants, and other pharmaceuticals) in filtered 

water samples are described. Data on method performance, including spike data and method 

detection limit analyses are provided and summarized. An estimate of precision is provided.

Quality-assurance data for sample collection and handling are presented. Quantitative data are 

presented for the seven pharmaceuticals in water samples. Occurrence data are provided for 19 

pharmaceuticals that were qualitatively identified in samples but were not quantified. Flow data 

at selected WWTP and streams also are included.

Between 2004-09, 35-38 effluent samples were collected from each of three WWTPs 

(wastewater treatment plants) in New York and analyzed for seven pharmaceuticals including 

opioids and muscle relaxants. Two WWTPs (NY2 and NY3) receive substantial flows (greater 

than 20 percent of plant flow) from PFFs and one (NY1) receives no PFF flow. Samples of 

effluents from 23 WWTP across the United States were analyzed once for these pharmaceuticals 

as part of a national survey. Maximum pharmaceutical effluent concentrations for the national 

survey and NY1 effluent samples were rarely (about 1 percent) greater than 1 μg/L. Four 

pharmaceuticals (methadone, oxycodone, butalbital and metaxalone) in samples of NY3 effluent 

had median concentrations ranging from 3.4 to greater than 400 μg/L. Maximum concentrations 

of oxycodone (1700 μg/L) and metaxalone (3800 μg/L) in samples from NY3 effluent exceeded 

1000 μg/L. Three pharmaceuticals (butalbital, carisoprodol, and oxycodone) in samples of NY2 
33

effluent had median concentrations ranging from 2 to 11 μg/L. These findings suggest that 

current manufacturing practices at these PFFs can result in pharmaceuticals concentrations from 

10 to 1000 times higher than those typically found in WWTP effluents.

Publically available information on pharmaceuticals formulated at the PMFs is limited.

Such information can be useful for designing studies that characterize the potential 

pharmaceutical source loadings to the environment from a PMF. Information provided in this 

report on pharmaceuticals formulated at PFFs that discharge to the two WWTPs is based on the a 

variety of sources, including direct FDA identification of selected pharmaceuticals formulated at 

the sites, a New York State Report indicating use of two pharmaceuticals at one of these sites, a 

web site operated by the U.S. National Institutes of Health (NIH) that identifies companies 

marketing or manufacturing pharmaceuticals, and manufacturers’ web sites that listing the 

pharmaceuticals marketed by the owners of the two PFFs.

Acknowledgments

The authors thank the many USGS scientists and field technicians that provided 

assistance in site selection, collection, and processing of samples included in this study. Michelle 

Hladick and Michael Focazio provided useful comments on the draft manuscript. The authors 

also thank the New York State Department of Environmental Conservation for supporting the 

sampling in New York State. This project was conducted by the USGS Cooperative Water 

Program, New York State Department of Environmental Conservation, and the USGS Toxic 

Substances Hydrology Program. Elizabeth Nystrom formatted the text, tables and figures.
34

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For more information concerning this report, contact

Director

U.S. Geological Survey

New York Water Science Center

425 Jordan Road

Troy, NY 12180-8349

dc_ny@usgs.gov

or visit our Web site at:

http://ny.water.usgs.gov
Phillips and others— Method Description, Quality Assurance, Environmental Data, and other Information for Analysis of Pharmaceuticals in Wastewater-Treatment-Plant Effluents, Streamwater, and Reservoirs, 2004-2009—OFR 2010–1102