Wyoming Department 

of Agriculture

Wyoming Department 

of Environmental 

Quality

Printed on recycled paper

Figure 1. Pathways of pesticide movement in the hydrologic cycle (modified from Barbash 

and Resek, 1996).

In cooperation with the Wyoming Department of Agriculture (WDA) and the Wyoming Department of 

Environmental Quality (WDEQ)

In 1991, members of local, State, and Federal governments, as well as industry and interest groups, formed the Groundwater and Pesticide Strategy Committee to prepare the State of Wyoming’s generic Management Plan for Pesticides in Ground 

Water. Part of this management plan is to sample and analyze Wyoming’s ground water for pesticides. In 1995, the U.S. 

Geological Survey, in cooperation with the Ground-water and Pesticide Strategy Committee, began statewide implementation of the sampling component of the State of Wyoming’s generic Management Plan for Pesticides in Ground Water. During 

2004–2005, baseline monitoring was conducted in Campbell County. This fact sheet describes and summarizes results of the 

baseline monitoring in Campbell County.

Pesticides in Ground Water

Synthetic organic pesticides are used to 

control weeds, insects, and other organisms in a wide variety of agricultural 

and nonagricultural settings. The use of 

pesticides has helped to make the United 

States the world’s largest producer of food 

(Barbash and Resek, 1996). Pesticide use, 

however, also has been accompanied by 

concerns about potential adverse effects 

on the environment and human health. 

A potential pathway for the transport of 

pesticides is through hydrologic systems, 

which supply water for both humans and 

natural ecosystems. Water is one of the 

primary ways pesticides are transported 

from an application area to other locations 

in the environment (fig. 1) (Barbash and 

Resek, 1996).

Pesticide contamination of ground 

water is a national issue because of the 

widespread use of pesticides, the expense 

and difficulty of remediating ground 

water, and the fact that ground water is 

used for drinking water by about one-half 

the Nation’s population. Although application rates and the variety of pesticides 

used may be greater in urban areas, concern over their presence in ground water is 

especially acute in rural agricultural areas 

where more than 95 percent of the population rely upon this resource for drinking 

water (Hutson and others, 2004).

Wyoming’s Pesticide Management Plan

The Ground-water and Pesticide Strategy Committee (GPSC) has developed 

the generic State Management Plan for 

Pesticides in Ground Water for the State of 

Wyoming (SMP) (Wyoming Ground-water 

and Pesticides Strategy Committee, 1999). 

Wyoming was required by the U.S. Environmental Protection Agency to have an 

SMP in order for individuals and organizations to continue using certain pesticides 

in the State. The SMP includes information relating to individuals and organizations involved with implementation of the 

SMP, methods of preventing ground-water 

contamination, ground-water monitoring, 

and the responses required if pesticides are 

detected in ground water.

One critical part of the SMP is groundwater monitoring. This ground-water monitoring program has two phases. The first 

phase, baseline monitoring, is designed 

Pesticides in Ground Water - Campbell County, Wyoming, 2004–2005

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006-3123

November 2006
Table 1. Summary of baseline monitoring for pesticides in Campbell County, August 2004 and April 2005.

[μg/L, micrograms per liter; E, value is estimated; C, estimated value used in calculation; --, not applicable]

Pesticide

Pesticide

trade name Pesticide action1

Number of

detections/

number of

samples2

Laboratory 

minimum

reporting level3

(μg/L)

Maximum

concentration

(μg/L)

Average

concentration

of detections

(μg/L)

Safe

drinking

water

standard4

(μg/L)

Focal pesticides detected in Campbell County ground water

Picloram Tordon Systemic herbicide 2/15 0.02 E10 C8 500

Tebuthiuron Spike Herbicide 2/16 .02 .03 .03 5500

Non-focal pesticides detected in Campbell County ground water

Diuron Durashield Herbicide 1/15 0.01 0.03 -- 510

Imidacloprid Admire, Provado Insecticide 2/15 .02 .03 C.03 --

Prometon Pramitol Non-selective herbicide 6/16 .02 .07 .04 5100

Focal pesticides not detected in Campbell County ground water

Alachlor, Aldicarb, Aldicarb Sulfone6, Aldicarb Sulfoxide6, Atrazine, Bromacil, Clopyralid, Cyanazine, 2,4-D,

DCPA, Dicamba, Hexazinone, Metalachlor, Metribuzin, Metsulfuron, Simazine, Telone

Focal pesticide not included in analysis of Campbell County ground water (no method of analysis available)

Difenzoquat

1

Meister (2002)

2

Each of the 8 wells was sampled twice. One well had only one analysis of picloram, diuron, and imidaclopid.

3

The laboratory minimum reporting level is the lowest concentration at which a 

pesticide concentration can be quantified without estimation.

4

U.S. Environmental Protection Agency Maximum Contaminant Level unless 

otherwise noted (U.S. Environmental Protection Agency, 2004).

5

U.S. Environmental Protection Agency Lifetime Health Advisory Level 

(U.S. Environmental Protection Agency, 2004).

6

Degradation product of aldicarb.

to determine what pesticides, if any, have 

entered into the county’s ground water. 

The second phase, problem identification 

monitoring, is used to gather additional 

information about the ground water near 

wells with samples having significant 

pesticide detections.

Baseline monitoring is prioritized by 

a county rank and the vulnerability of 

the county’s ground water to pesticides. 

During the development of the SMP, the 

GPSC evaluated each county in Wyoming 

to determine the potential vulnerability of 

the county’s ground water to pesticides. 

Each county was ranked according to the 

extent of cropland and urban areas in the 

county, as well as the amount of pesticides 

sold within the county in 1991 (Wyoming 

Ground-water and Pesticides Strategy 

Committee, 1999).

A ground-water vulnerability map was 

prepared for the uppermost or shallowest 

aquifer (Hamerlinck and Arneson, 1998). 

A Geographic Information System was 

used to overlay seven layers describing 

hydrogeology and land use. Ground water 

is vulnerable because of either inherent 

sensitivity of the hydrogeology or the 

combination of the sensitivity and associated land use. The map was used to assist 

in the selection of monitoring sites in each 

Converse (2003–2004), Hot Springs 

(2003–2004), Carbon (2004–2005), 

Sublette (2004–2005), and Niobrara and 

Weston (2005–2006) Counties.

Ground-Water Monitoring in 

Campbell County

Ground water in Campbell County 

was ranked twenty-first most vulnerable 

to pesticide contamination in Wyoming 

(Wyoming Ground-water and Pesticide 

Strategy Committee, 1999). The vulnerability map created by the Spatial Data 

and Visualization Center (Hamerlinck and 

Arneson, 1998), identifies unconsolidated 

Quaternary-age alluvial deposits in the 

county and Tertiary formations that underlie urban land use as the most vulnerable 

to pesticides (shown as red or yellow on 

fig. 2).

Eight wells were selected in Campbell 

County (fig. 3) for baseline monitoring. 

All wells were located in the red or yellow 

areas shown on figure 2. The Quaternaryage alluvial deposits in these areas were 

not thick enough to provide water for 

wells, and all wells sampled were completed in either the Tertiary-age Wasatch 

Formation or Fort Union Formation. All 

county. The monitoring focuses on areas 

where the ground water is most vulnerable.

The GPSC selected 18 pesticides 

and 2 degradation products as the focal 

pesticides for analysis as part of the SMP 

(table 1). The analytical methods used 

to detect the focal pesticides also detect 

115 other pesticides and degradation 

products. Any additional pesticides that 

were detected are listed in table 1 as nonfocal pesticides. Ground water from all 

wells in the baseline-monitoring program 

was analyzed for the pesticides listed in 

table 1, with the exception of difenzoquat, 

for which an analytical method was not 

available.

The goal of the ground-water monitoring part of the SMP is to analyze 

ground-water samples for pesticides 

in all 23 Wyoming counties. To date, 

sampling has been completed in Goshen 

(1995–1996), Park (1997), Washakie 

(1997–1998), Fremont (1998–1999), 

Laramie (1998–1999), Lincoln (1998–

1999), Big Horn (1999–2000), Sheridan 

(1999–2000), Crook (2000–2001), 

Johnson (2000–2001), Platte (2000–2001), 

Natrona (2001–2002), Sweetwater 

(2001–2002), Teton (2001–2002), 

Uinta (2002–2003), Albany (2003–2004), 
Little

Bitter Creek

Creek

Horse Horse

Wild

Rawhide

Creek

Creek

Creek

Creek Caballo

Belle

Hay

Creek

Spring

Creek

Porcupine Creek

Little Thunder Creek

Black Thunder Cr

Fourche

Cr

Wildcat

Spotted Hor r se C

Cr Olmstead

River

River

Cottonwood

Powder

River

Powder

Cottonwood Cr

Wright

Pine Tree

Savageton

Pleasantdale

Weston

Gillette

WYOMING

MONTANA

WYOMING

Campbell

County

106°00' 105°45' 105°30' 105°15'

43°30'

43°45'

44°00'

44°15'

44°30'

44°45'

45°00'

15 MILES

0 5 10 15 KILOMETERS

0 5 10

R. 69 W.

T. 41 N.

T. 42 N.

T. 43 N.

T. 44 N.

T. 45 N.

T. 46 N.

T. 47 N.

T. 48 N.

T. 49 N.

T. 50 N.

T. 51 N.

T. 52 N.

T. 53 N.

T. 54 N.

T. 55 N.

T. 56 N.

T. 57 N.

T. 58 N.

R. 76 W. R. 75 W. R. 74 W. R. 73 W. R. 72 W. R. 71 W. R. 70 W.

Base modified from U.S. Bureau of the

Census digital data, 2001

Public land survey system from Wyoming

Water Resources Center digital data, 1994

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30',

central meridian 105°30' 

59

59

50

59

387

16

14

I-90

I-90

EXPLANATION

Vulnerability to pesticide

contamination

High

Medium high

Medium

Medium low

Low

Figure 2. Vulnerability of Campbell County, Wyoming ground water to pesticide contamination 

(from Hamer­linck and Arneson, 1998).

wells were sampled twice, once in August 2004 

and once in April 2005.

Two of the 19 focal pesticides and 3 nonfocal pesticides were detected in Campbell 

County (table 1). Pesticides were detected 

in three of the eight wells sampled in Campbell County; concentrations of each detected 

pesticide were less than 1/50 of the applicable 

drinking-water standard (U.S. Environmental 

Protection Agency, 2004) (table 1).

Data Distribution and 

Availability

Sampling results have been 

provided to local groups interested in pesticides in ground 

water in Campbell County. 

The information can be used 

by citizens and local governments to help understand current conditions. Analytical 

results of the Campbell

County sampling can be found 

in Blajszczak and others 

(2005), and Blajszczak and 

others (2006) or on the Internet at http://waterdata.usgs.

gov/wy/nwis/qwdata. Analytical results and fact sheets for 

all counties sampled to date 

are available from the U.S. 

Geological Survey in Cheyenne by phone, email, or on 

the Internet at http://wy.water.

usgs.gov/projects/pesticide/.

References

Barbash, J.E., and Resek, E.A., 

1996, Pesticides in ground 

water—Distribution, trends, 

and governing factors: Chelsea, Mich., Ann Arbor Press, 

Pesticides in the Hydrologic 

System series, v. 2, 588 p.

Barbash, J.E., Thelin, G.P., 

Kolpin, D.W., and Gilliom, 

R.J., 1999, Distribution of 

major herbicides in ground 

water of the United States: 

U.S. Geological Survey 

Water-Resources Investigations 

Report 98–4245, 64 p.

Blajszczak, E.J., Mason, J.P., 

Watson, K.R., Roberts, S.C., 

and Miller, K.A., 2005, Waterresources data, Wyoming, 

water year 2004, Volume 2. 

Ground Water: U.S. Geological Survey Water-Data Report 

WY–04–2, 181 p.

Blajszczak, E.J., Mason, J.P., 

Watson, K.R., Roberts, S.C., 

and Miller, K.A., 2006, Waterresources data, Wyoming, 

water year 2005, Volume 2. 

Ground Water: U.S. Geological Survey Water-Data Report 

WY–05–2, 173 p.

The most commonly detected pesticide (6 of 

16 samples) in Campbell County was prometon, 

which is the active ingredient in the generaluse pesticide Pramitol. Prometon typically is 

detected in areas with urban land use (Barbash 

and others, 1999). Prometon was the most commonly detected pesticide in Albany, Carbon, 

Converse, Crook, Johnson, Natrona, Sheridan, 

Sublette, Teton, and Uinta Counties.
Little

Bitter Creek

Creek

Horse Horse

Wild

Rawhide

Creek

Creek

Creek

Creek Caballo

Belle

Hay

Creek

Spring

Creek

Porcupine Creek

Little Thunder Creek

Black Thunder Cr

Fourche

Cr

Wildcat

Spotted Hor r se C

Cr Olmstead

River

River

Cottonwood

Powder

River

Powder

Cottonwood Cr

Wright

Pine Tree

Savageton

Pleasantdale

Weston

Gillette

WYOMING

MONTANA

WYOMING

Campbell

County

15 MILES

0 5 10 15 KILOMETERS

0 5 10

R. 69 W.

T. 41 N.

T. 42 N.

T. 43 N.

T. 44 N.

T. 45 N.

T. 46 N.

T. 47 N.

T. 48 N.

T. 49 N.

T. 50 N.

T. 51 N.

T. 52 N.

T. 53 N.

T. 54 N.

T. 55 N.

T. 56 N.

T. 57 N.

T. 58 N.

R. 76 W. R. 75 W. R. 74 W. R. 73 W. R. 72 W. R. 71 W. R. 70 W.

59

59

50

59

387

16

14

I-90

I-90

106°00' 105°45' 105°30' 105°15'

43°30'

43°45'

44°00'

44°15'

44°45'

44°30'

45°00'

Quaternary alluvial and

 terrace deposits

EXPLANATION

No pesticide detected

 in samples

Pesticide detected in at

 least one sample

Base modified from U.S. Bureau of the

Census digital data, 2001

Public land survey system from Wyoming

Water Resources Center digital data, 1994

Albers Equal-Area Conic projection

Standard parallels 29°30' and 45°30',

central meridian 105°30' 

Figure 3. Location of wells sampled in Campbell County, Wyoming, and notation of pesticide detection in 

samples from each well.

Hamerlinck, J.D., and Arneson, 

C.S., eds., 1998, Wyoming 

ground water vulnerability 

assessment handbook: Volume 2. 

Assessing ground water vulnerability to pesticides: University 

of Wyoming, Laramie, Spatial 

Data and Visualization Center 

Publication SDVC 98–01–2, 

variable pagination.

Hutson, S.S., Barber, N.L., Kenny, 

J.F., Linsey, K.S., Lumia, D.S., 

and Maupin, M.A., 2004, Estimated use of water in the United 

States in 2000: U.S. Geological 

Survey Circular 1268, 46 p.

Meister, R.T., 2002, Farm chemicals handbook: Willoughby, 

Ohio, Meister Publishing Co., 

variable pagination.

U.S. Environmental Protection 

Agency, 2004, Drinking water 

regulations and health advisories: EPA 822–R–04–0005, 12 p.

Wyoming Ground-water and Pesticides Strategy Committee, 1999, 

Wyoming generic state management plan for pesticides and 

ground water: prepared for Wyoming Department of Agriculture, 

Cheyenne, Wyoming, 103 p.

• Prepared by Cheryl A. Eddy-Miller 

and Kendra J. Remley

• Layout prepared by Suzanne C. 

Roberts

This fact sheet was prepared by the 

U.S. Geological Survey (USGS), the 

Wyoming Department of Agriculture 

(WDA), and the Wyoming Department of Environmental Quality, Water 

Quality Division (WDEQ). All agencies 

are members of the Ground-water and 

Pesticide Strategy Committee.

This project has been funded in part 

with a Section 319 grant from the U.S. 

Environmental Protection Agency to 

Wyoming Department of Environmental 

Quality’s Non-Point Source Program.

The use of trade, product, industry, or 

firm names is for descriptive purposes 

only and does not imply endorsement 

by the U.S. Government.

For more information, contact:

Roy Reichenbach

Wyoming Department of Agriculture

2219 Carey Avenue

Cheyenne, Wyoming 82002

(307) 777-6590

Kevin Frederick

Wyoming Department of Environmental Quality, 

Water Quality Division

Herschler Building West, 4th Floor

Cheyenne, Wyoming 82002

(307) 777-5985

Cheryl Eddy Miller

U.S. Geological Survey

2617 E. Lincolnway, Suite B

Cheyenne, Wyoming 82001

(307) 778-2931

Email: cemiller@usgs.gov