Quality and Sources of Shallow Ground

Water in Areas of Recent Residential

Development in Salt Lake Valley,

Salt Lake County, Utah

Water-Resources Investigations Report 03–4028

U.S. Department of the Interior

U.S. Geological Survey

National Water-Quality Assessment Program
U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 03-4028

Quality and Sources of Shallow Ground Water in 

Areas of Recent Residential Development in Salt 

Lake Valley, Salt Lake County, Utah 

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM

By Susan A. Thiros

Salt Lake City, Utah

2003
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

For additional information write to:

District Chief

U.S. Geological Survey

2329 West Orton Circle

Salt Lake City, Utah 84119

Copies of this report can be purchased from:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver Federal Center

Denver, CO 80225-0286

1-888-ASK-USGS

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. 

Government.

District Chief

U.S. Geological Survey

2329 West Orton Circle

Salt Lake City, Utah 84119

http://ut.water.usgs.gov
iii

FOREWORD

The U.S. Geological Survey (USGS) is committed to serve the Nation with accurate and timely scientific 

information that helps enhance and protect the overall quality of life, and facilitates effective management of water, 

biological, energy, and mineral resources (http://www.usgs.gov/). Information on the quality of the Nation’s water 

resources is of critical interest to the USGS because it is so integrally linked to the long-term availability of water 

that is clean and safe for drinking and recreation and that is suitable for industry, irrigation, and habitat for fish and 

wildlife. Escalating population growth and increasing demands for the multiple water uses make water availability, 

now measured in terms of quantity and quality, even more critical to the long-term sustainability of our 

communities and ecosystems.

The USGS implemented the National Water-Quality Assessment (NAWQA) program to support national, 

regional, and local information needs and decisions related to water-quality management and policy 

(http://water.usgs.gov/nawqa). Shaped by and coordinated with ongoing efforts of other Federal, State, and local 

agencies, the NAWQA program is designed to answer: What is the condition of our Nation’s streams and ground 

water? How are the conditions changing over time? How do natural features and human activities affect the quality 

of streams and ground water, and where are those effects most pronounced? By combining information on water 

chemistry, physical characteristics, stream habitat, and aquatic life, the NAWQA program aims to provide sciencebased insights for current and emerging water issues and priorities. NAWQA results can contribute to informed 

decisions that result in practical and effective water-resource management and strategies that protect and restore 

water quality.

Since 1991, the NAWQA program has implemented interdisciplinary assessments in more than 50 of the 

Nation’s most important river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/ 

nawqamap.html). Collectively, these Study Units account for more than 60 percent of the overall water use and 

population served by public water supply, and are representative of the Nation’s major hydrologic landscapes, 

priority ecological resources, and agricultural, urban, and natural sources of contamination. 

Each assessment is guided by a nationally consistent study design and methods of sampling and analysis. 

The assessments thereby build local knowledge about water-quality issues and trends in a particular stream or 

aquifer while providing an understanding of how and why water quality varies regionally and nationally. The 

consistent, multi-scale approach helps to determine if certain types of water-quality issues are isolated or pervasive, 

and allows direct comparisons of how human activities and natural processes affect water quality and ecological 

health in the Nation’s diverse geographic and environmental settings. Comprehensive assessments on pesticides, 

nutrients, volatile organic compounds, trace metals, and aquatic ecology are developed at the national scale through 

comparative analysis of the Study-Unit findings (http://water.usgs.gov/nawqa/natsyn.html). 

The USGS places high value on the communication and dissemination of credible, timely, and relevant 

science so that the most recent and available knowledge about water resources can be applied in management and 

policy decisions. We hope this NAWQA publication will provide you the needed insights and information to meet 

your needs, and thereby foster increased awareness and involvement in the protection and restoration of our 

Nation’s waters. 

The NAWQA program recognizes that a national assessment by a single program cannot address all waterresource issues of interest. External coordination at all levels is critical for a fully integrated understanding of 

watersheds and for cost-effective management, regulation, and conservation of our Nation’s water resources. The 

program, therefore, depends extensively on the advice, cooperation, and information from other Federal, State, 

interstate, Tribal, and local agencies, non-government organizations, industry, academia, and other stakeholder 

groups. The assistance and suggestions of all are greatly appreciated.

Robert M. Hirsch

Associate Director for Water
iv
 v

CONTENTS

Foreword .............................................................................................................................................................. iii

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

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

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

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

Ground-Water Hydrology ........................................................................................................................... 3

Land Use ..................................................................................................................................................... 5

Acknowledgments....................................................................................................................................... 5

Study Design and Methods .................................................................................................................................. 5

Site Selection............................................................................................................................................... 8

Sample Collection and Analysis ................................................................................................................. 8

Quality Assurance ....................................................................................................................................... 11

Ground-Water Quality.......................................................................................................................................... 13

Field Parameters.......................................................................................................................................... 13

Inorganic Constituents ................................................................................................................................ 13

Major Ions .......................................................................................................................................... 13

Trace Elements................................................................................................................................... 18

Radionuclides..................................................................................................................................... 20

Nutrients and Dissolved Organic Carbon ................................................................................................... 23

Pesticides..................................................................................................................................................... 25

Volatile Organic Compounds...................................................................................................................... 27

Sources of Ground-Water Recharge .................................................................................................................... 35

Stable Isotopes ............................................................................................................................................ 35

Tritium and Tritium/Helium-3 .................................................................................................................... 38

Chlorofluorocarbons ................................................................................................................................... 40

Effects of Shallow Ground-Water Quality on Deeper Ground-Water Quality.................................................... 41

Relation Between Ground-Water Quality and Land Use..................................................................................... 42

Summary .............................................................................................................................................................. 42

References Cited .................................................................................................................................................. 44

Appendix .............................................................................................................................................................. 47
vi 

FIGURES

Figure 1 Map showing location and geographic features of Salt Lake Valley, Utah....................................... 4

Figure 2. Generalized block diagram showing the basin-fill deposits and ground-water flow system in 

Salt Lake Valley, Utah....................................................................................................................... 5

Figure 3. Map showing location of recharge and discharge areas and monitoring wells installed in areas 

of recent residential development, Salt Lake Valley, Utah ............................................................... 6

Figure 4. Map showing land use in Salt Lake Valley, Utah, 1994.................................................................... 7

Figure 5. Graph showing percentage of land-use type mapped within a 1,640-foot radius of monitoring 

wells in Salt Lake Valley, Utah ......................................................................................................... 10

Figure 6. Map showing dissolved-solids concentration in water sampled from monitoring wells in areas 

of recent residential development, Salt Lake Valley, Utah ............................................................... 17

Figure 7. Diagrams showing major-ion composition of water sampled from monitoring wells in areas 

of recent residential development, Salt Lake Valley, Utah ............................................................... 19

Figure 8. Map showing arsenic concentration in water sampled from monitoring wells in areas of recent 

residential development, Salt Lake Valley, Utah............................................................................... 21

Figure 9. Map showing radon concentration in water sampled from monitoring wells in areas of recent 

residential development, Salt Lake Valley, Utah............................................................................... 22

Figure 10. Map showing nitrate concentration in water sampled from monitoring wells in areas of recent 

residential development, Salt Lake Valley, Utah............................................................................... 24

Figure 11. Graph showing detection frequency of pesticides in water sampled from monitoring wells in 

areas of recent residential development, Salt Lake Valley, Utah ...................................................... 25

Figure 12. Graph showing concentration of selected pesticides in water sampled from monitoring wells in 

areas of recent residential development, Salt Lake Valley, Utah ...................................................... 26

Figure 13. Map showing total concentration of atrazine and its degradation products in water sampled 

from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah ............. 28

Figure 14. Map showing prometon concentration in water sampled from monitoring wells in areas of 

recent residential development, Salt Lake Valley, Utah.................................................................... 29

Figure 15. Graph showing detection frequency of volatile organic compounds in water sampled from 

monitoring wells in areas of recent residential development, Salt Lake Valley, Utah...................... 30

Figure 16. Graph showing concentration of selected volatile organic compounds in water sampled from 

monitoring wells in areas of recent residential development, Salt Lake Valley, Utah...................... 31

Figure 17. Map showing chloroform concentration in water sampled from monitoring wells in areas of 

recent residential development, Salt Lake Valley, Utah.................................................................... 32

Figure 18. Map showing tetrachloroethylene (PCE) concentration in water sampled from monitoring 

wells in areas of recent residential development, Salt Lake Valley, Utah......................................... 33

Figure 19. Graph showing relation between delta deuterium and delta oxygen-18 for shallow groundwater and surface-water samples from Salt Lake Valley, Utah......................................................... 37

Figure 20. Graph showing relation between delta deuterium and delta oxygen-18 for water samples from 

selected wells and from Little Cottonwood Creek, Salt Lake Valley, Utah ...................................... 38

Figure 21. Graph showing tritium concentration in precipitation and in water sampled from monitoring 

wells in areas of recent residential development, Salt Lake Valley, Utah......................................... 40
 vii

TABLES

Table 1. Description of 30 monitoring wells sampled in Salt Lake Valley, Utah, 1999 ................................. 9

Table 2. Summary of field parameters, inorganic constituents, and dissolved organic carbon in water 

sampled from 30 monitoring wells in areas of recent residential development, Salt Lake 

Valley, Utah ....................................................................................................................................... 14

Table 3. Concentration and detection frequency of pesticides detected in water sampled from 30 

monitoring wells in areas of recent residential development, Salt Lake Valley, Utah...................... 15

Table 4. Concentration and detection frequency of volatile organic compounds detected in water 

sampled from 30 monitoring wells in areas of recent residential development, Salt Lake Valley, 

Utah.................................................................................................................................................... 16

Table 5. Stable isotope ratio, tritium concentration, and apparent age for water sampled from 30 

monitoring wells in areas of recent residential development, Salt Lake Valley, Utah...................... 36

Table 6. Field parameters for water sampled from monitoring wells in Salt Lake Valley, Utah, 1999 .......... 47

Table 7. Concentration of dissolved major ions in water sampled from monitoring wells in Salt Lake 

Valley, Utah, 1999 ............................................................................................................................. 48

Table 8. Concentration of trace elements in water sampled from monitoring wells in Salt Lake Valley, 

Utah, 1999.......................................................................................................................................... 50

Table 9. Concentration of nutrient constituents and organic carbon in water sampled from monitoring 

wells in Salt Lake Valley, Utah, 1999 ............................................................................................... 52

Table 10. Pesticides and degradation products analyzed for in water sampled from monitoring wells in 

Salt Lake Valley, Utah, 1999............................................................................................................. 53

Table 11. Concentration of dissolved pesticides detected in water sampled from monitoring wells in Salt 

Lake Valley, Utah, 1999 .................................................................................................................... 56

Table 12. Volatile organic compounds analyzed for in water sampled from monitoring wells in Salt Lake 

Valley, Utah, 1999 ............................................................................................................................. 58

Table 13. Concentration of volatile organic compounds detected in water sampled from monitoring wells 

in Salt Lake Valley, Utah, 1999......................................................................................................... 60

Table 14. Quality-control data for dissolved major ions in blank water and water sampled from monitoring 

wells in Salt Lake Valley, Utah, 1999 ............................................................................................... 62

Table 15. Quality-control data for dissolved trace elements in blank water and water sampled from 

monitoring wells in Salt Lake Valley, Utah, 1999 ............................................................................ 63

Table 16. Quality-control data for dissolved nutrient constituents and organic carbon in blank water and 

water sampled from monitoring wells in Salt Lake Valley, Utah, 1999............................................ 64

Table 17. Quality-control data for selected dissolved pesticides in blank water, 1999..................................... 65

Table 18. Quality-control data for selected volatile organic compounds in blank water, 1999 ........................ 66

Table 19. Percent recovery for pesticide surrogates in blank water and water sampled from monitoring 

wells in Salt Lake Valley, Utah, 1999 ............................................................................................... 68

Table 20. Percent recovery for volatile organic compound surrogates in blank water and water sampled 

from monitoring wells in Salt Lake Valley, Utah, 1999.................................................................... 69

Table 21. Percent recovery for matrix spikes of pesticides in water sampled from monitoring wells in 

Salt Lake Valley, Utah, 1999............................................................................................................. 70

Table 22. Percent recovery for matrix spikes of volatile organic compounds in water sampled from 

monitoring wells in Salt Lake Valley, Utah, 1999 ............................................................................ 73
viii 

CONVERSION FACTORS, DATUMS, AND ABBREVIATED WATER-QUALITY 

UNITS

Water temperature in degrees Celsius (oC) and degrees Fahrenheit (oF) may be converted by using the 

following equations:

Vertical coordinate information is referenced to the North American Vertical Datum of 1929 (NAVD 

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

Concentration of chemical constituents in water is reported either in milligrams per liter (mg/L) or 

micrograms per liter (μg/L). Milligrams per liter and micrograms per liter are units expressing the 

concentration of chemical constituents in solution as weight (grams) of solute per unit volume (liter) 

of water. A liter of water is assumed to weigh 1 kilogram, except for brines or water at high temperatures because of changes in the density of the water. For concentrations less than 7,000 mg/L or 

7,000,000 μg/L, the numerical value is the same as for concentrations in parts per million or parts per 

billion, respectively.

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

Radon concentration in water is reported as picocuries per liter (pCi/L). Stable isotope ratios are 

reported as per mil, which is equivalent to parts per thousand. Tritium concentration in water is 

reported as tritium units (TU). The ratio of 1 atom of tritium to 1018 atoms of hydrogen is equal to 1 

TU or 3.2 pCi/L. Chlorofluorocarbons measured in picograms per kilogram (pg/kg) are equivalent to 

parts per quadrillion.

Multiply By To obtain

foot (ft) 0.3048 meter

gallon (gal) 3.785 liter

inch (in.) 25.4 millimeters

mile (mi) 1.609 kilometer

square mile (mi2) 2.59 square kilometer

oF = 1.8 (oC) + 32 oC = (oF - 32) / 1.8
Abstract 1

Quality and Sources of Shallow Ground Water in Areas 

of Recent Residential Development in Salt Lake Valley, 

Salt Lake County, Utah

By Susan A. Thiros

ABSTRACT

Residential and commercial development of 

about 80 square miles that primarily replaced 

undeveloped and agricultural areas occurred in 

Salt Lake Valley, Utah, from 1963 to 1994. This 

study evaluates the occurrence and distribution of 

natural and anthropogenic compounds in shallow 

ground water underlying recently developed (post 

1963) residential and commercial areas. 

Monitoring wells from 23 to 153 feet deep were 

installed at 30 sites. Water-quality data for the 

monitoring wells consist of analyses of field 

parameters, major ions, trace elements, nutrients, 

dissolved organic carbon, pesticides, and volatile 

organic compounds. 

Dissolved-solids concentration ranged from 

134 to 2,910 milligrams per liter (mg/L) in water 

from the 30 monitoring wells. Dissolved arsenic 

concentration in water from 12 wells exceeded the 

drinking-water maximum contaminant level of 10 

micrograms per liter. Water from monitoring wells 

in the northwestern part of the valley generally 

contained higher arsenic concentrations than did 

water from other areas. Nitrate concentration in 

water sampled from 26 of the 30 monitoring wells 

(86.7 percent) was higher than a background level 

of 2 mg/L, indicating a possible human influence. 

Nitrate concentrations ranged from less than 0.05 

to 13.3 mg/L.

Fifteen of the 104 pesticides and pesticide 

degradation products analyzed for were detected 

in 1 or more water samples from the monitoring 

wells. No pesticides were detected at 

concentrations that exceeded U.S. Environmental 

Protection Agency drinking-water standards or 

guidelines for 2002. The high detection frequency 

of atrazine, a restricted-use pesticide, in residential 

areas on the west side of Salt Lake Valley may be 

the result of application in agricultural or 

industrial areas that have been converted to 

residential uses or application in areas upgradient 

from the residential areas that was then transported 

by ground water.

Fifteen of the 86 volatile organic 

compounds analyzed for were detected in 1 or 

more water samples from the monitoring wells. 

The most frequently detected volatile organic 

compounds were chloroform (90 percent), 

bromodichloromethane (56.7 percent), 

tetrachloroethylene (53.3 percent), and 1,1,1-

trichloroethane (50 percent). The widespread 

occurrence of chloroform and 

bromodichloromethane in shallow ground water is 

likely a result of the recharge of chlorinated 

public-supply water used to irrigate lawns and 

gardens in residential areas of Salt Lake Valley. 

Tetrachloroethylene (PCE), primarily used as a dry 

cleaning agent and solvent, was detected in water 

from 16 wells. 

On the basis of stable isotope ratios, ground 

water from the monitoring wells is a mixture of 

varying amounts of local precipitation and surface 

water that has been subjected to evaporation. 

Because of evaporation, canal water diverted from 

the Jordan River and used for irrigation is more 

enriched in deuterium and oxygen-18 relative to 

precipitation occurring locally or on the adjacent 
2 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

mountains. Several wells on the east side of the 

valley are upgradient from canals that divert water 

from the Jordan River but contain a component of 

water that has been concentrated by evaporation. 

Chloroform was detected in water from these 

wells; thus, water is likely a mixture of infiltration 

from local precipitation and seepage of water used 

for public supply.

Water from most of the wells had a tritium 

concentration from 10 to 20 tritium units, a range 

that most likely is made up of water recharged 

from the present to about 15 years ago and within 

the time frame of residential development in the 

area of the wells. The correlation between tritium 

concentration in recently recharged ground water 

and in precipitation indicates that most or all of the 

water in the shallow ground-water system is from 

the land surface with little or no mixing with older 

water. Ground water from most of the monitoring 

wells was contaminated with chlorofluorocarbons, 

which also indicates that the water has been in 

contact with the land surface.

The shallow and deeper ground-water 

systems in the southeastern part of the valley are 

separated by sequences of fine-grained deposits 

that perch the shallow ground water and confine 

the deeper aquifer. Subsurface inflow from the 

Wasatch Range is the main source of recharge to 

the deeper aquifer compared to local precipitation 

and unconsumed irrigation water that recharges 

the shallow ground-water system. As a result, the 

deeper aquifer in this part of the valley is probably 

more isolated from activities occurring at the land 

surface that can affect the quality of shallow 

ground water. Water from local precipitation and 

seepage from irrigation and canals, primary 

sources of recharge to the shallow aquifer, also 

may be major sources of recharge to the deeper 

aquifer in the southwestern part of Salt Lake 

Valley where thin or discontinuous confining 

layers are present. Where this is the case, activities 

occurring at land surface have the potential to 

affect the water quality of the deeper aquifer. 

No correlation was determined between the 

percentage of residential land use surrounding the 

monitoring wells and the concentration of 

dissolved solids, arsenic, atrazine and its 

degradation products, prometon, chloroform, or 

nitrate in water sampled from the wells. Relatively 

low concentrations of chloroform corresponded to 

the four highest concentrations of atrazine and its 

degradation products, probably because of atrazine 

use on agricultural or nonirrigated industrial and 

vacant land.

INTRODUCTION

Ground water is used for public supply in Salt 

Lake Valley and accounts for about one third of the 

water used. Withdrawals from the principal aquifer in 

Salt Lake Valley are regulated and limited by the Utah 

Division of Water Rights because the resource is overallocated and can be adversely affected by large waterlevel declines and water-quality degradation. Water 

from the overlying shallow aquifer is not currently used 

for public supply and has limited use for stock and 

domestic supply. Leakage from the shallow aquifer to 

the deeper principal aquifer is possible where a 

downward gradient exists and confining layers are thin 

and/or discontinuous. Because of this connection and 

an increased demand for water caused by population 

growth, more information is needed about the shallow 

ground-water resource in the valley. 

Residential and commercial development of 

about 80 mi2 that primarily replaced undeveloped and 

agricultural areas occurred in Salt Lake Valley, Utah, 

from 1963 to 1994. The chemical composition and 

effects of human activities on the quality of shallow 

ground water in the recently developed residential and 

commercial areas were studied as part of the U.S. 

Geological Survey (USGS) National Water-Quality 

Assessment (NAWQA) program. The Great Salt Lake 

Basins study unit is 1 of more than 50 study areas 

selected to meet the objectives of the NAWQA 

program. The land-use study in Salt Lake Valley 

consisted of 30 monitoring wells installed and sampled 

in 1999 in residential/commercial areas where shallow 

ground water has the potential to move to the deeper 

aquifer used for public supply. The water samples were 

analyzed for major ions, trace elements, radon, 

nutrients, pesticides, and volatile organic compounds 

(VOCs). Analyses also were done to determine the 

source and time of recharge of the shallow ground 

water.
Introduction 3

Purpose and Scope

The purpose of this report is to evaluate the 

occurrence and distribution of natural and 

anthropogenic compounds in shallow ground water 

underlying areas of recently developed (post 1963) 

residential and commercial land use. The report 

describes the water quality in the shallow ground-water 

system and relates it to natural and anthropogenic 

factors, such as surrounding land uses and associated 

human activities. It also presents information on the 

sources and time of recharge on the basis of stable 

isotope and age-dating methods.

Description of Study Area

Salt Lake Valley is an urban area bounded by the 

Wasatch Range, Oquirrh Mountains, Traverse 

Mountains, and Great Salt Lake (fig. 1). It is about 28 

mi long and 18 mi wide and generally corresponds to 

the populated part of Salt Lake County, which contains 

the Salt Lake City metropolitan area. The population in 

Salt Lake County in 2000 was about 898,000 (U.S. 

Census Bureau, 2002), and is growing rapidly. The 

population almost doubled between 1963 and 1994, 

corresponding to a large increase in land developed for 

residential and commercial use. Population in Salt 

Lake County is projected to be about 1,029,000 in 2010 

and 1,233,000 in 2020 (Wasatch Front Regional 

Council, 2000), which will require more water for 

public supply. Because the natural boundaries of the 

valley restrict expansion of residential areas, 

population growth will occur mainly through increased 

population density. Changes in land use resulting from 

population growth will likely affect shallow groundwater quality through changes in sources and quality of 

recharge.

Mountain streams draining the Wasatch Range 

discharge into the Jordan River, which flows north 

along the axis of the valley and discharges into Great 

Salt Lake. The climate in Salt Lake Valley is semiarid, 

with a 1961-90 average annual precipitation of about 

10 to 20 in. Lawns and gardens in the valley require 

irrigation to supplement precipitation during the 

growing season.

Ground-Water Hydrology

A generalized model of the saturated basin-fill 

deposits in Salt Lake Valley consists of a relatively 

deep unconfined aquifer near the mountain fronts that 

becomes confined toward the center of the valley by 

layers of fine-grained deposits (fig. 2). Collectively, the 

deeper aquifers are known as the principal aquifer. 

Overlying the deeper confined aquifer is a shallow, 

generally unconfined aquifer. The primary recharge 

area for the principal aquifer is near the mountain 

fronts where there are no substantial layers of finegrained deposits to impede downward movement of 

water. Leakage of water from the shallow aquifer to the 

deeper confined aquifer is possible where a downward 

gradient exists and confining layers are thin or 

discontinuous. These conditions can exist in the 

secondary recharge area and were mapped by 

Anderson and others (1994, p. 6). A discharge area 

exists where there is an upward gradient from the 

deeper confined aquifer to the overlying shallow 

aquifer. Discharge areas generally exist in the center of 

the valley (fig. 2) along the Jordan River (fig. 3). 

Recharge and discharge areas in Salt Lake Valley are 

shown in figure 3. 

Overlying the confining layers is shallow ground 

water that is either localized in extent because it is 

perched on fine-grained deposits or is more laterally 

continuous and forms an aquifer. The shallow aquifer 

in the valley is generally unconfined, although in some 

areas the first saturated zone in the subsurface was 

encountered beneath a confining layer (Thiros, 2003). 

The shallow aquifer is susceptible to contamination 

from activities related to land use because of its 

proximity to land surface and the absence of a thick 

confining layer. The deeper unconfined aquifer also is 

vulnerable because of a lack of confining layers that 

can impede the downward movement of contaminated 

ground water. Movement of contaminated water from 

the shallow aquifer and the deeper unconfined aquifer 

can degrade water quality in the deeper confined 

aquifer. Hydrogeologic information for the shallow 

basin-fill deposits collected during the land-use study is 

presented in Thiros (2003). Faults within and bounding 

the basin-fill deposits may affect ground-water 

movement in the valley. Water from wells in the 

northwestern part of the valley near faults generally is 

warmer, indicating movement from greater depths. 
4 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data,

1979 and 1980, 1:100,000

Universal Transverse Mercator projection, Zone 12 Bear

Lake

UTAH

IDAHO

WYOMING

Great

 Salt

 Lake

Utah

Lake

Salt

Lake

City

112r15'

 Great

 Salt

Lake

Tailings ponds

80

15

Approximate limit of basin-fill

deposits in Salt Lake Valley

40r30'

40r45'

111r37'30"

Salt Lake County

Jordan River

OQUIRRH MOUNTAINS

WASATCH RANGE

Great

Salt Lake

Basins

study

area

215

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

TRAVERSE

MOUNTAINS

Coon Creek

Barneys Creek

Bingham Creek

City Creek

Red

Creek

Butte

Creek

Emigration

Creek

Parleys

Creek Mill

Creek

Big Cottonwood

Creek

Little Cottonwood

Butterfield Creek

Rose Creek

Provo Canal

Reservoir

Utah

Canal

Lake

South

Jordan

Canal

Distributing

Utah

Lake

Canal

Salt and

Canal

Draper

Irrigation

Canal

East Jordan

Canal

Jordan

Salt

Lake

and

Canal

Surplus

EXPLANATION

Fault

Approximate boundary of basin-fill

deposits in Salt Lake Valley

Figure 1. Location and geographic features of Salt Lake Valley, Utah.
Study Design and Methods 5

Land Use

Historically, much of the industrial land use in 

Salt Lake Valley was located near the Jordan River with 

the urban area centered in the northeastern part of the 

valley. Agricultural land in the valley decreased from 

145 mi2 in 1960 to 67 mi2 in 1994, while urban land 

increased from 89 to 198 mi2 in the same period (Utah 

Department of Natural Resources, Division of Water 

Resources, 1999). Land use in urban areas of the valley 

in 1994 was about 63 percent residential, 6 percent 

commercial, 14 percent industrial, and 17 percent other 

(includes open spaces, idle spaces, transportation, and 

utilities) (Utah Department of Natural Resources, 

Division of Water Resources, 1995) (fig. 4). Many of 

the recently developed residential/commercial areas 

overlie the secondary recharge areas of the basin-fill 

ground-water system where a downward gradient exists 

between the shallow and deeper aquifers.

Acknowledgments

The USGS thanks the landowners and the 

officials of municipalities and Salt Lake County who 

allowed USGS personnel access to their properties for 

the purpose of installing and sampling the land-use 

study monitoring wells.

STUDY DESIGN AND METHODS

The design for NAWQA urban land-use studies 

focuses on the quality of recently recharged ground 

water in urban settings and its relation to natural factors 

and human activities. A study plan was provided to 

ensure consistency of data collection and study design 

(Squillace and Price, 1996) and allows for comparison 

among land-use studies from across the country.

Basin-fill deposits of

Tertiary age

Great Salt

Lake

Fine-grained

deposits

Consolidated

rock

Water level

in shallow aquifer

Water level in

deeper confined aquifer

Deeper

confined

aquifer

Shallow

aquifer

Confining layer

Primary

recharge

area

Perched

water

Secondary

recharge

area

Discharge

area

EXPLANATION

Direction of ground-water movement

Deeper

unconfined

aquifer

Water level in

deeper unconfined

aquifer

Coarse-grained

deposits

Principal

aquifer

Basin-fill deposits of

Quaternary age Modified from Hely, and others, 1971

Figure 2. Generalized block diagram showing the basin-fill deposits and ground-water flow system in Salt Lake Valley, Utah.
6 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Great

Salt

Lake

Tailings ponds

40°30'

40°45'

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Perched aquifer—Data from Hely and others, 1971

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Monitoring well—Number is well name in table 6

1

2

3

4

5 7 6

8

11 10

9

14

20

17

24 25

30

31 33

18

22

27 29 26S

26D

32

34

37

39

41

41

112°07'30" 111°48'

SALT LAKE COUNTY

DAVIS COUNTY

Figure 3. Location of recharge and discharge areas and monitoring wells installed in areas of recent residential development, Salt Lake

Valley, Utah.
Study Design and Methods 7

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

EXPLANATION

Excavated

Water

Riparian

Agriculture

Corn

Unknown

Approximate boundary of basin-fill deposits in Salt Lake Valley

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Residential and (or) commercial land use

developed during 1963–94

Residential

Commercial

Industrial

Transportation/utilities

Open or idle

Great

Salt

Lake

Discharge area

Secondary recharg

Primary recharge area

e area

Figure 4. Land use in Salt Lake Valley, Utah, 1994.
8 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Site Selection

Potential well locations were selected by using a 

computerized, stratified random selection process 

(Scott, 1990) to ensure that the data collected are 

unbiased and representative of the quality of water 

underlying recently developed residential and 

commercial areas. The program selected 41 sites in Salt 

Lake Valley that met the study criteria: (1) a location in 

residential and commercial areas developed during 

1963-94, (2) a downward gradient between the shallow 

and deeper aquifers, and (3) a minimum distance 

between each site of 0.62 mi (1 kilometer). Areas 

developed after 1994 were excluded from this study 

because of the time necessary for new construction to 

affect the ground-water system (Squillace and Price, 

1996). Areas developed before 1963, such as 

downtown Salt Lake City, also were excluded because 

of a greater potential for the land use to have changed 

with time. The sites were checked for depth to ground 

water, access, and permission to drill from the 

landowner.

Monitoring wells were installed at 30 of the 41 

sites according to NAWQA protocols (Lapham and 

others, 1995) and were completed in the shallowest 

water-bearing zone capable of supplying water (fig. 3). 

The monitoring wells ranged from 23 to 153 ft deep 

and generally were completed with a 10-ft length of 

screen about 5 ft below the water table (table 1). One 

site was completed with two wells to determine 

variations in water quality of the shallow aquifer with 

depth (well 26S is screened from 26 to 31 ft below land 

surface and well 26D is screened from 62 to 72 ft 

below land surface). The water level at another site 

dropped below the bottom of the well and no water 

sample was collected. Water levels in the wells range 

from about 5 to 135 ft below land surface.

Land-use characteristics within a 1,640-ft (500-

meter) radius around each monitoring well were 

determined from aerial photographs taken in 

September 1999. Land uses shown on the photographs 

were field checked and documented by using 

procedures described in Koterba (1998). The land-use 

data for this study are plotted as percentages of the total 

on figure 5. Single and multifamily residences were the 

most common land use within the prescribed radius of 

the monitoring wells and ranged from 24 to 96 percent 

of the area with an average of 70 percent. Other land 

uses mapped within the radius of the wells include 

commercial, schools, churches, parks, golf courses, 

agricultural, roads, and barren property. The amount of 

commercial land use in the radius around each 

monitoring well ranged from 0 to 40 percent.

Sample Collection and Analysis

Ground-water samples were collected in the 

summer and fall of 1999 by using a stainless-steel 

submersible pump and fittings connected to Teflon 

tubing. Samples were collected and processed 

according to protocols in Koterba and others (1995). 

Each monitoring well was purged of three to five 

casing volumes of water prior to sampling. Water 

temperature, pH, specific conductance, dissolved 

oxygen, turbidity, discharge, and depth to water were 

monitored periodically during the purge cycle. Groundwater samples were collected after measurements of 

these parameters had stabilized. Analytical results for 

the samples are presented in tables 6 to 13 (appendix).

Five wells were sampled in the spring and fall of 

2000 and the fall of 2001 in addition to the land-use 

study sampling done in 1999 to determine if seasonal 

changes in water quality occurred. Two of the wells are 

located on the west side of the valley (wells 5 and 33) 

and three are on the east side (wells 26D, 27, and 32). 

These monitoring wells will be sampled on a biennial 

schedule after the study to monitor long-term waterquality trends in the residential land-use study area. 

The samples will be analyzed for major ions, trace 

elements, radon, nutrients, pesticides, and volatile 

organic compounds (VOCs).

Water samples were analyzed for sulfide and 

chlorine in the field with a portable spectrophotometer. 

Sulfide concentration was measured to help determine 

oxidation/reduction conditions. Chlorine concentration 

was measured to determine if chlorinated water was 

present in the ground-water sample. Premeasured 

amounts of reagent in vacuum-sealed ampoules were 

mixed with the water sample after the ampoule seal 

was broken. Transmittance at a set wavelength through 

the ampoule containing the water sample and reagent is 

measured by the spectrophotometer and converted to a 

concentration on the basis of calibration tables from the 

reagent supplier. Alkalinity was determined onsite by 

incremental titration of filtered sample water with 

sulfuric acid. 

The USGS National Water-Quality Laboratory 

(NWQL) in Denver, Colorado, analyzed the water 

samples for major ions, nutrients, dissolved organic 
Study Design and Methods 9

carbon (DOC), selected trace elements, radon, 

pesticides, and VOCs. Major ions and trace elements 

were analyzed by using inductively coupled 

plasma/mass spectrometry, atomic absorption 

spectrometry, or ion chromatography (Fishman and 

Friedman, 1989; Fishman, 1993; and Faires, 1993). 

Nutrient concentrations were determined by 

colorimetry (Fishman, 1993; Patton and Truitt, 1992). 

DOC was analyzed for by using ultraviolet-promoted 

persulfate oxidation and infrared spectrometry 

(Brenton and Arnett, 1993). Radon was analyzed for by 

using liquid scintillation (American Society for Testing 

and Materials, 1996). Filtered water samples were 

analyzed for 86 pesticides by using capillary column 

gas chromatography/mass spectrometry (Zaugg and 

others, 1995) and 65 pesticides by using highperformance liquid chromatography/mass spectrometry 

(HPLC/MS) (Furlong and others, 2001). The 

HPLC/MS method was used to analyze the samples 

before its final approval; therefore, concentrations of 

pesticides analyzed by this method are considered 

provisional. Unfiltered water samples were analyzed 

for 86 VOCs by using purge and trap capillary column 

gas chromatography/mass spectrometry (Conner and 

others, 1998). 

Analyses of the stable isotopes of water, 

deuterium and oxygen-18 were done at the USGS 

Stable Isotope Laboratory in Reston, Virginia. The 

Table 1. Description of 30 monitoring wells sampled in Salt Lake Valley, Utah, 1999

[Well identifier, see figure 3 for well location; residential land use within 1,640 feet of well]

Well

identifier

Area of

valley

Residential

land use

(percent)

Altitude

of land

surface

Well

depth

Top of

screened

interval

Bottom of

screened

interval

Water level

March 2000

(feet below land surface)

1 northwest 84.5 4,308 48.5 38 48 32.77

2 northwest 64.0 4,294 38.5 28 38 19.55

3 northwest 89.3 4,371 114 103 113 79.96

4 northwest 23.6 4,331 38.5 28 38 14.01

5 northwest 39.4 4,426 43.5 33 43 27.59

6 northwest 50.6 4,324 38.5 28 38 23.46

7 northwest 71.6 4,396 43.5 33 43 27.09

8 northwest 71.8 4,487 67.5 57 67 63.37

9 northwest 41.0 4,312 38.5 28 38 12.57

10 northwest 76.9 4,350 83.5 73 83 67.94

11 northwest 83.7 4,462 83.5 73 83 70.75

14 southwest 70.5 4,579 48.5 38 48 27.97

17 southwest 57.8 4,380 38.5 28 38 17.72

18 east 79.5 4,411 106 95 105 76.85

20 southwest 72.3 4,477 92.5 82 92 84.66

22 east 77.9 4,538 36 25.5 35.5 21.61

24 southwest 93.1 4,473 124 113 123 81.98

25 southwest 96.1 4,414 68.5 58 68 49.67

26D east 81.8 4,591 77.5 62 72 32.77

26S east 81.8 4,591 31.5 26 31 30.43

27 east 90.4 4,499 73.5 63 73 58.69

29 east 91.0 4,532 34 23.5 33.5 9.02

30 southwest 66.7 4,455 68.5 58 68 58.12

31 southwest 72.8 4,562 154 143 153 143.19

32 east 35.0 4,640 88.5 78 88 76.18

33 southwest 38.9 4,466 95.5 85 95 74.14

34 east 49.7 4,486 77.5 67 77 57.81

37 east 92.9 4,725 73 62.5 72.5 45.18

39 east 84.0 4,758 106 95.5 106 94.02

41 east 66.9 4,550 23 12.5 22.5 5.48
10 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

deuterium analysis uses a hydrogen equilibration 

method (Coplen and others, 1991) and the oxygen-18 

analysis uses a carbon dioxide equilibration technique 

(Epstein and Mayeda, 1953). Analytical uncertainties 

for delta deuterium and delta oxygen-18 values are 2 

and 0.2 per mil, respectively. Chlorofluorocarbons 

(CFCs) were analyzed at the USGS CFC Laboratory in 

Reston, Virginia, by using purge and trap gas 

chromotography (Busenberg and Plummer, 1992). The 

detection limit for CFCs is about 0.3 pg/kg of water, 

which is equivalent to 0.3 parts per quadrillion 

(Plummer and Friedman, 1999). The University of 

Utah, Department of Geology and Geophysics, Tritium 

and Noble Gases Laboratory in Salt Lake City, Utah, 

analyzed the water samples for tritium and helium-3. 

Tritium concentrations were determined by helium 

ingrowth (Bayer and others, 1989). The method 

involves degassing the sampled water and then 

isolating it under a vacuum in a special container. The 

sample is stored from 1 month to 1 year, and then the 

concentration of helium-3, the daughter product of 

tritium, is measured by using a magnetic sector-field 

mass spectrometer.

VOCs that are not detected in a water sample are 

reported as less than the laboratory reporting level 

(LRL). The LRL for each VOC represents the 

minimum concentration that can be identified, 

measured, and reported with 99 percent confidence 

(Childress and others, 1999). All other constituents or 

pesticide compounds that are not detected in a water 

sample are reported as less than the minimum reporting 

level (MRL). The MRL is defined by the NWQL 

(Timme, 1995) as the smallest measured concentration 

of a constituent that may be reliably measured by using 

a given analytical method. The MRL or LRL for each 

constituent or compound indicates relative analytical 

precision and detection sensitivity, but some 

concentrations are reported below the reporting level if 

the identification criteria for the method were met. 

Concentrations for detections below MRLs or LRLs 

are designated as estimated values. The MRLs for 

pesticides and LRLs for VOCs analyzed for by the 

NAWQA program are lower than those of analyses 

done for regulatory purposes.

LAND USE WITHIN 1,640 FEET (500 METERS) OF

MONITORING WELL, IN PERCENT

0

10

20

30

40

50

60

70

80

90

100

4 32 33 5 9 34 6 17 2 30 41 14 7 8 20 31 10 22 18 26 11 39 1 3 27 29 37 24 25

MONITORING WELL

Other

Alfalfa field

Roads

Parks and golf courses

Schools and churches

Vacant

Commercial

Residential

EXPLANATION

Figure 5. Percentage of land-use type mapped within a 1,640-foot radius of monitoring wells in Salt Lake Valley, Utah.
Study Design and Methods 11

Concentrations of water-quality constituents and 

compounds were compared to the drinking-water 

standards for 2002 set by the U.S. Environmental 

Protection Agency (USEPA) (U.S. Environmental 

Protection Agency, 2002). The maximum contaminant 

level (MCL) is the maximum concentration of a 

contaminant permissible in a public-water system. The 

MCL primarily applies to water sampled from 

distribution lines and at taps after being disinfected. 

MCLs are based on a level at which no known or 

anticipated adverse effects on human health occur and 

which allows an adequate margin of safety, but also 

considers the cost and feasibility of meeting the 

standard. The lifetime health advisory level (HAL) is 

the concentration of a chemical in drinking water that 

is not expected to cause any adverse noncarcinogenic 

effects during a lifetime of exposure (U.S. 

Environmental Protection Agency, 2002). It is based on 

health effects information and is provided as technical 

guidance for regulatory and management officials.

Quality Assurance

A quality-assurance program was used in the 

field (Koterba and others, 1995) and in the laboratory 

to evaluate the bias and variability of the analytical 

results and to ensure data reliability. Quality-control 

samples were collected as part of sampling the 30 

monitoring wells and included 6 field-blank samples 

for major ions, nutrients, VOCs, pesticides, and trace 

elements; 6 source-solution blank samples for DOC 

and 5 for VOCs; 1 trip-blank sample for VOCs; 3 

replicate samples for major ions, nutrients, trace 

elements, and radon; 3 field-spiked samples for VOCs 

and selected pesticides; and 3 laboratory-spiked 

samples for selected pesticides. Analytical results for 

the field-blank and ground-water replicate samples are 

listed in the tables 14-18 (appendix).

Field-blank samples were collected to evaluate 

contamination introduced during sample collection, 

processing, and analysis. Water certified to have less 

than the MRL or LRL for the analyzed constituents and 

compounds was pumped through the sampling pump, 

tubing, and other sampling equipment in the same 

manner as a regular ground-water sample. Relatively 

large volumes of water flowed through the sampling 

equipment prior to collection of a ground-water 

sample, whereas a much smaller amount of blank water 

flowed through the system prior to collection of the 

field-blank sample. This additional flushing and rinsing 

with ground water is believed to have minimized 

residual concentrations possibly left after the 

equipment cleaning procedure.

DOC was detected in water from all six fieldblank samples, three at concentrations that were less 

than the lowest concentration measured in the groundwater samples and three within the range of measured 

concentrations. Because DOC was not detected in 

water from the source-solution blank samples, it likely 

results from residual cleaning agents in the sampling 

equipment (rinsed with 1 to 3 gal of blank water). 

Additional rinsing with ground water during the 

purging cycle of sampling (usually more than 20 gal) 

likely reduces DOC concentrations in the 

environmental samples to below those determined for 

the field blanks. Some of the DOC measured in water 

from the wells may be from the sampling equipment; 

therefore, DOC concentrations may be greater than 

what was actually present in the aquifer. Caution 

should be used in interpreting these data.

Nitrate plus nitrite and ammonia each were 

detected in one field-blank sample and ammonia plus 

organic nitrogen was detected in two field-blank 

samples. Concentrations of ammonia and ammonia 

plus organic nitrogen in the field-blank samples were 

within the range of concentrations measured in the 

ground-water samples; therefore, data for these 

constituents should be interpreted with caution. The 

concentration of nitrate plus nitrite in water from the 

field-blank sample is much lower than that for water 

from most of the environmental samples, and any 

residual contamination is probably diluted to less than 

the reporting level by the purging of ground water 

through the sampling lines. Nitrate plus nitrite 

concentrations measured in the ground-water samples 

are assumed to be uncontaminated on the basis of the 

field-blank data.

Zinc was detected in water from five of the six 

field blanks at concentrations in the range of those 

determined for the ground-water samples; therefore, 

the ground-water data are likely biased. Small amounts 

of chromium, nickel, and copper also were detected in 

water from two to four of the field blanks. Chromium 

and nickel are used in stainless steel and may be 

coming from the stainless steel connections used on the 

Teflon tubing. The concentration of these constituents 

in the field-blank samples generally is lower than those 
12 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

in the ground-water samples, but contamination may 

bias concentrations that are in the same range. Caution 

should be used in interpreting these data.

Of the 104 pesticides or pesticide breakdown 

products analyzed for, only 4 were detected in fieldblank samples. The herbicides cycloate, fenuron, and 

imazaquin were detected in water from one, one, and 

two field-blank samples, respectively; and in four, zero, 

and two ground-water samples, respectively, analyzed 

in the same sample set at the NWQL. These 

compounds also were detected in water from laboratory 

blanks at a similar concentration; therefore, their 

presence in the ground-water and field-blank samples 

is probably the result of laboratory contamination. 

Detection of cycloate, fenuron, and imazaquin is 

questioned; therefore, these compounds are not 

included in the pesticide data analysis.

The VOCs ethylbenzene, 1,2,4-

trimethylbenzene, o-ethyltoluene, and m/p xylene were 

detected in two to five field-blank samples at 

concentrations greater than those estimated for the 

ground-water samples. The compounds 1,2,3-

trimethylbenzene, 1,3,5-trimethylbenzene, and oxylene also were detected in a field-blank sample and 

in a ground-water sample at similar concentrations. No 

VOCs were detected in the source-solution blanks or in 

the trip blank. These compounds were probably 

introduced into the blank sample when the blank water 

was poured into a cylinder containing the sampling 

pump. The atmosphere can receive these compounds, 

in addition to benzene and toluene, from the 

incomplete combustion of gasoline used to power the 

generator or nearby vehicles. Ground-water samples 

are not exposed to air except when they are transferred 

from the sample-collection chamber to the preservation 

chamber, so the likelihood of contamination is less than 

when collecting the field-blank sample. Detection of 

the compounds listed above in ground water is 

questioned and is not included in the VOC data 

analysis. 

Sequential replicate ground-water samples were 

collected from three wells to determine the 

concentration variability for radon, major ions, and 

trace elements. Replicate samples collected from two 

wells were analyzed for DOC and nutrients. 

Concentrations for most constituents in the sample 

pairs were within 10 percent. Low concentrations of 

ammonia plus organic nitrogen, orthophosphorus, 

fluoride, and copper resulted in maximum differences 

between the sample pairs of about 25 percent. The zinc 

concentration in water from one replicate sample was 

twice as much as was measured in the ground-water 

sample and may be related to contamination.

Surrogate pesticide and VOC compounds were 

added in known concentrations to the ground-water and 

blank-water samples and percent recovery was 

determined for each surrogate (tables 19 and 20, 

appendix). These surrogate compounds are similar 

chemically to other compounds that were analyzed for 

and provide information on sample-matrix effects and 

analyte recovery. Pesticide surrogate recovery in the 

ground-water samples ranged from 73 to 106 percent 

for alpha-HCH-d6, 41 to an estimated 106 percent for 

barban, 40 to 98 percent for caffeine, 85 to 141 percent 

for diazinon, and an estimated 35 to 101 percent for 

2,4,5-T. Relatively low recovery of caffeine and 2,4,5-

T in water from wells 6, 8, 10, 11, 24, 25, 30, 31, and 

33 (all on the west side of the valley) corresponded 

with relatively high recovery of the surrogate diazinon. 

Water from the valley's west side seems to have a 

different effect on these surrogates than water from the 

east side. VOC surrogate recovery in the ground-water 

samples ranged from 88 to 121 percent for 1,2-

dichloroethane-d4, 73 to 105 percent for 1,4-

bromofluorobenzene, and 91 to 109 percent for 

toluene-d8.

Spike solutions containing known concentrations 

of target VOC and pesticide compounds were added to 

three replicate ground-water samples (tables 21 and 22, 

appendix) to determine analyte recovery in the sample 

matrix and to evaluate the effectiveness of the 

analytical methods for selected analytes. Recovery of 

most compounds was within 25 percent of the amount 

present in the unspiked sample plus the amount added 

in the spike solution. Recovery of the atrazine 

degradation products deethylatrazine and 2-

hydroxyatrazine was less than (34 percent mean 

recovery) and greater than (140 percent mean 

recovery), respectively, the amount added to the three 

matrix-spiked samples. Low mean recovery means that 

the compound may not have been detected in the 

sample if present at low concentrations. High mean 

recovery means that the detections are real, but 

concentrations may be biased high. Recovery of 

chloromethane was greater than the amount added to 

the three matrix-spiked samples (164 percent mean 

recovery). Water from well 34 had the only detection of 

chloromethane (estimated at 0.1 μg/L) in the study, 

which on the basis of the spike-recovery data may be a 

higher concentration than actually exists in the aquifer. 
Ground-Water Quality 13

Ninety percent of the ground-water samples from 

this study analyzed for pesticides with the HPLC/MS 

method exceeded the recommended 4-day holding time 

prior to sample extraction (Furlong and others, 2001). 

Degradation of pesticides during extended sample 

storage is likely, and concentrations and detection 

frequencies for the pesticides analyzed by this method 

may be biased low.

GROUND-WATER QUALITY

Ground-water quality data for the 30 monitoring 

wells sampled in recently developed residential areas 

of Salt Lake Valley consist of field parameters, major 

ions, trace elements, nutrients, DOC, pesticides, and 

VOCs. Summary statistics for field parameters, major 

ions, trace elements, nutrients, and DOC are listed in 

table 2; pesticides in table 3; and VOCs in table 4. 

Analytical results for the samples collected from the 30 

wells as part of this study are listed in tables 6 to 13 

(appendix). Water-quality data for these and other 

samples discussed in the following sections are also 

available on the internet at URL 

http://waterdata.usgs.gov/ut/nwis/qwdata.

Field Parameters

Field parameters measured during sampling are 

depth to water, water temperature, specific 

conductance, pH, alkalinity, dissolved oxygen, 

turbidity, chlorine, and sulfide concentration (table 2 

and table 6, appendix). Depth to water in the wells 

ranged from 5.27 ft below land surface at well 41 in the 

southeastern part of the valley to 135.17 ft below land 

surface at well 31 in the southwestern part. All of the 

samples were within the range specified for pH to meet 

secondary drinking water regulations (U.S. 

Environmental Protection Agency, 2002). Turbidity of 

water sampled from the monitoring wells ranged from 

0.1 to 12 nephelometric turbidity units (NTU). 

Turbidity measurements can be used to evaluate 

potential colloidal contributions to measured 

concentrations of iron, manganese, and other elements. 

Chlorine was detected in water from eight monitoring 

wells, seven of which are on the east side of the valley. 

The chlorine may be from chlorinated water that has 

recharged the shallow ground-water system because 

chloroform also was detected in the samples.

The concentration of dissolved oxygen in water 

from the wells varied from 0.7 to 8.7 mg/L and 

provides information on the oxidation-reduction 

(redox) state of the water. The redox state can affect 

what constituents are present and at what 

concentrations. Oxidizing conditions are generally 

defined by dissolved oxygen concentrations greater 

than 2.0 mg/L and no detectable concentrations of 

nitrite, ammonia, sulfide, iron, or manganese. 

Reducing conditions are indicated by dissolved oxygen 

concentrations less than 2.0 mg/L and the presence of 

nitrite, ammonia, sulfide, iron, or manganese. Because 

dissolved oxygen can be introduced to ground water 

during the sampling process, these other indicators 

were used to help determine redox conditions (tables 6, 

7, 8, and 9, appendix). On the basis of these indicators, 

6 wells had water under reducing conditions, 12 wells 

had water under oxidizing conditions, and the 

remaining 12 wells had water with dissolved oxygen 

concentrations greater than 2.0 mg/L, but the presence 

of nitrite, ammonia, sulfide, iron, or manganese 

resulted in indefinite conditions. Well 29 was the only 

well on the east side of the valley with definite 

reducing conditions.

Inorganic Constituents

Major Ions

Dissolved-solids concentration (determined as 

residue at 180oC) ranged from 134 to 2,910 mg/L in 

water from the 30 monitoring wells (fig. 6). The 

secondary drinking-water regulation for dissolved 

solids of 500 mg/L (U.S. Environmental Protection 

Agency, 2002) was exceeded in water from 23 wells. 

Water from wells on the east and west sides of the 

valley had median concentrations of 405 and 1,300 

mg/L, respectively. The least mineralized water was 

from well 26S (fig. 3) next to Little Cottonwood Creek. 

Water in the creek (USGS site number 10167800) is 

primarily snowmelt runoff from the Wasatch Range in 

the spring and early summer and had a dissolved-solids 

concentration of 67 mg/L in May 2000. The most 

mineralized water was from well 20 and contained 

1,480 mg/L of sulfate. Sulfate was the predominant 

anion in water from the four monitoring wells (wells 

10, 17, 20, and 24), all on the west side of the valley, 

with more than 2,000 mg/L dissolved solids (table 7, 

appendix).
14 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 2. Summary of field parameters, inorganic constituents, and dissolved organic carbon in water sampled from 30 monitoring wells in areas of 

recent residential development, Salt Lake Valley, Utah—Continued

Parameters, constituents, and reporting units Number of 

detections

Minimum 

reporting level

Minimum

detected

concentration

Maximum 

detected

concentration

Median of 

detections

USEPA drinkingwater standards or 

health advisories1

Field parameters

Well depth (feet) 30 — 23 153.5 68.2 —

Water level (feet) 30 — 5.27 135.17 30.91 —

Water temperature (oC) 29 — 10.5 19 16 —

Specific conductance (μS/cm) 30 — 235 3,700 1,405 —

pH (standard units) 30 — 6.8 7.8 7.3 6.5-8.5 (SDWR)

Alkalinity (mg/L as CaCO3) 30 — 68 659 308 —

Oxygen, dissolved (mg/L) 29 — .7 8.7 5.3 —

Turbidity (NTU) 30 — .1 12 .5

Chlorine (μg/L) 8 30 35 100 50

Sulfide (μg/L) 12 10 10 240 10

Major ions

Bicarbonate (mg/L as HCO3) 30 — 82 804 392 —

Bromide, dissolved (mg/L) 29 .01 .01 1.40 .22 —

Calcium, dissolved (mg/L) 30 .01 20.6 448 95.9 —

Chloride, dissolved (mg/L) 30 .1 12.9 456 184 250 (SDWR)

Fluoride, dissolved (mg/L) 30 .1 .1 1.9 .6 4.0 (MCL)

Iron, dissolved (μg/L) 11 10 M 540 M 300 (SDWR)

Magnesium, dissolved (mg/L) 30 .008 4.88 175 39.8 —

Manganese, dissolved (μg/L) 24 2.2 E1.4 148 11.2 50 (SDWR)

Potassium, dissolved (mg/L) 30 .09 1.35 57.8 10.6 —

Silica, dissolved (mg/L) 30 .1 6.5 51.6 37 —

Sodium, dissolved (mg/L) 30 .1 10.3 473 162 —

Sulfate, dissolved (mg/L) 30 .1 16.9 1,480 136 250 (SDWR)

Dissolved solids, residue at 180oC, (mg/L) 30 10 134 2,910 833 500 (SDWR)

Dissolved solids, sum of constituents (mg/L) 30 — 131 2,830 856 500 (SDWR)

Trace elements

Aluminum, dissolved (μg/L) 24 1 1 10 2 50-200 (SDWR)

Antimony, dissolved (μg/L) 2 1.00 1.30 1.69 1.54 6 (MCL)

Arsenic, dissolved (μg/L) 24 1.0 1.1 19.6 10.5 10 (MCL)

Barium, dissolved (μg/L) 30 1.0 11.8 255 52.4 2,000 (MCL)

Beryllium, dissolved (μg/L) 0 1.00 — — — 4 (MCL)

Cadmium, dissolved (μg/L) 0 1.00 — — — 5 (MCL)

Chromium, dissolved (μg/L) 23 1.0 E.5 4.7 1.7 2 100 (MCL)

Cobalt, dissolved (μg/L) 2 1.00 1.05 1.09 1.07 —

Copper, dissolved (μg/L) 26 1.0 1.0 10 2.3 1,000 (SDWR)

Lead, dissolved (μg/L) 0 1.00 — — — —

Molybdenum, dissolved (μg/L) 28 1.0 1.5 99.1 5.2 40 (HAL)

Nickel, dissolved (μg/L) 28 1.00 1.30 7.88 3.12 100 (HAL)

Radon-222, total (pCi/L) 30 26 243 2,190 574 300 (MCL)

Selenium, dissolved (μg/L) 15 1.0 1.2 13.0 2.6 50 (MCL)

Silver, dissolved (μg/L) 0 1.0 — — — 100 (HAL)

Uranium, dissolved (μg/L) 29 1.00 1.50 92.7 10.4 30 (MCL)

Zinc, dissolved (μg/L) 27 1 1 8 3 2,000 (HAL)

Table 2. Summary of field parameters, inorganic constituents, and dissolved organic carbon in water sampled from 30 monitoring wells in areas of recent 

residential development, Salt Lake Valley, Utah

[USEPA, U.S. Environmental Protection Agency; —, not applicable or no standard; oC, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees 

Celsius; SDWR, Secondary Drinking-Water Regulations; mg/L, milligrams per liter; NTU, nephelometric turbidity units; μg/L, micrograms per liter; MCL, 

Maximum Contaminant Level; M, presence of constituent verified but not quantified; E, estimated; HAL, Lifetime Health-Advisory Level; pCi/L, picocuries 

per liter]
Ground-Water Quality 15

Nutrients and dissolved organic carbon

Ammonia, dissolved as N (mg/L) 7 .020 .021 .043 .029 30 (HAL)

Ammonia plus organic nitrogen, dissolved as 

N (mg/L)

27 .10 E.06 .34 .14 —

Carbon, organic, dissolved as C (mg/L) 30 .30 .60 4.6 1.5 —

Nitrite, dissolved as N (mg/L) 5 .010 .012 .107 .019 1 (MCL)

Nitrate plus nitrite, dissolved as N (mg/L) 29 .050 .200 13.3 6.85 10 (MCL)

Phosphorus, dissolved as P (mg/L) 29 .004 .006 .207 .033 —

Orthophosphorus, dissolved as P (mg/L) 27 .010 .015 .189 .031 — 1 U.S. Environmental Protection Agency (2002).

2 Maximum contaminant level is for total chromium.

Table 2. Summary of field parameters, inorganic constituents, and dissolved organic carbon in water sampled from 30 monitoring wells in areas of 

recent residential development, Salt Lake Valley, Utah—Continued

Parameters, constituents, and reporting units Number of 

detections

Minimum 

reporting level

Minimum

detected

concentration

Maximum 

detected

concentration

Median of 

detections

USEPA drinkingwater standards or 

health advisories1

 Table 3. Concentration and detection frequency of pesticides detected in water sampled from 30 monitoring wells in areas of recent residential 

development, Salt Lake Valley, Utah

[Maximum contaminant level is the U.S. Environmental Protection Agency established drinking-water standard (U.S. Environmental Protection Agency, 

2002). Lifetime health advisory level is defined as the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic 

effects for a lifetime of exposure (U.S. Environmental Protection Agency, 2002). E, estimated value; —, not applicable or no standard]

Pesticide Trade name(s) or 

abbreviation Predominant use

Number 

of detections

Maximum 

concentration

Minimum 

detected 

concentration

Minimum 

reporting 

level

Maximum 

contaminant 

level

Lifetime 

health 

advisory 

level

(micrograms per liter)

Atrazine AAtrex restricted use herbicide 23 1.58 E 0.004 0.001 3 —

Deethylatrazine DEA, Desethylatrazine degradation product of atrazine 21 E .320 E .004 .002 — —

Deethyldeisopropylatrazine DEIA degradation product of atrazine 19 E .12 E .01 .06 — —

Deisopropylatrazine — degradation product of atrazine 

and simazine

4 E .02 E .01 .07 — —

2-Hydroxyatrazine — degradation product of atrazine 10 E .511 E .044 .193 — —

Bromocil Hyvar, Urox B general use herbicide 1 .19 — .081 — 90

Caffeine — occurs naturally in tea, coffee, 

and cola nuts 

2 E .029 E .011 .081 — —

Cycloate1 Ro-Neet herbicide 4 E .04 E .03 .05 — —

Diazinon D-Z-N restricted use insecticide 1 E .002 — .002 — .6

Diuron Karmex, Direx general use herbicide 1 .32 — .08 — 10

Imazaquin1 Ala-Scept, Scepter general use herbicide 2 E .006 E .006 .103 — —

Malathion Cythion general use insecticide 1 .006 — .005 — 100

P,P' DDE — degradation product of DDT 1 E .002 — .006 — —

Picloram Access, Tordon restricted use herbicide 1 .47 — .07 500 500

Prometon Pramitol general use herbicide 15 .518 E .004 .018 — 100

Simazine Aquazine, Princep restricted use herbicide 13 .027 E .004 .005 4 4

Tebuthiuron Brush, Spike, Perflan restricted use herbicide 4 .120 E .012 .010 — 500

1 Presence in the ground-water and field-blank samples may be the result of laboratory contamination.
16 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 4. Concentration and detection frequency of volatile organic compounds detected in water sampled from 30 monitoring wells in areas of recent 

residential development, Salt Lake Valley, Utah

[Maximum contaminant level is the U.S. Environmental Protection Agency established drinking-water standard (U.S. Environmental Protection Agency, 

2002). Lifetime health advisory level is defined as the concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic 

effects for a lifetime of exposure (U.S. Environmental Protection Agency, 2002). E, estimated value; M, presence of compound verified but not quantified; 

—, not applicable or no standard]

Volatile organic compound Alternative name or 

abbreviation Predominant use Number of detections

Maximum 

concentration

Minimum 

detected 

concentration

Laboratory 

reporting 

level

Maximum 

contaminant 

level

Lifetime 

health 

advisory 

level

(micrograms per liter)

Benzene1 — fuel-related compound 2 E 0.01 M 0.04 5 —

Bromodichloromethane 2 Dichlorobromomethane chlorination byproduct 17 .51 E .02 .05 80 —

Carbon disulfide — naturally occurring 3 E .10 E .01 .07 — —

Chloroform 2 Trichloromethane solvent, chlorination 

byproduct

27 2.41 E .03 .05 80 —

Chloromethane Methyl chloride solvent 1 E .1 — .5 — 30

1,1-Dichloroethane Ethylidine chloride solvent 1 E .03 — .07 — —

1,2-Dichloroethane Ethylene dichloride metal degreaser 1 .4 — .1 5 —

1,1-Dichloroethylene 1,1-DCE organic synthesis 2 E .05 E .01 .04 7 6

Dichloromethane Methylene chloride solvent, metal degreaser 6 E .3 M .4 5 —

Ethylbenzene 1 Ethylbenzol fuel-related compound 2 E .02 E .01 .03 700 700

o-Ethyl toluene 1 — fuel-related compound 1 E .01 — .06 — —

Methyl tert-butyl ether MTBE fuel oxygenate 1 E .1 — .2 — —

Tetrachloroethylene Tetrachloroethene, PCE solvent 16 7.8 M .1 5 10

Tetrachloromethane Carbon tetrachloride solvent, metal degreaser 1 E .01 — .06 5 —

Toluene 1 Methylbenzene fuel-related compound 2 E .01 E .01 .05 1,000 1,000

1,1,1-Trichloroethane Methyl chloroform, TCA solvent 15 .22 E .01 .03 200 200

Trichloroethylene Trichloroethene, TCE solvent 5 1.54 E .02 .04 5 —

Trichlorofluoromethane Freon 11, CFC-11 refrigerant, aerosol propellant 2 E .09 E .04 .09 — 2,000

1,1,2-

Trichlorotrifluoroethane

CFC-113 refrigerant, aerosol propellant 1 E .08 — .06 — —

1,2,3-Trimethylbenzene1 — fuel-related compound 1 M — .1 — —

1,2,4-Trimethylbenzene1 Psuedocumene fuel-related compound 2 E .03 E .01 .06 — —

1,3,5-Trimethylbenzene1 — fuel-related compound 1 E .01 — .04 — —

m- and p-Xylene1 1,3 + 1,4-

Dimethylbenzene

fuel-related compound 4 E .08 E .01 .06 310,000 310,000

o-Xylene1 1,2-Dimethylbenzene fuel-related compound 1 E .02 — .04 310,000 310,000

1 Presence in the ground-water and (or) field-blank samples may be the result of contamination in the field while sampling.

2 A trihalomethane, it is a byproduct of the chlorination disinfection process. The maximum contaminant level for total trihalomethanes is 80 

micrograms per liter. 3 Maximum contaminant level and lifetime health advisory level are for total xylene.
Ground-Water Quality 17

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Dissolved-solids concentration in water sampled from monitoring wells, in milligrams per liter

134 – 500

500 – 1,000

1,000 – 2,000

2,000 – 2,910

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 6. Dissolved-solids concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, 

Utah.
18 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

The secondary drinking-water regulation for 

sulfate (250 mg/L) (U.S. Environmental Protection 

Agency, 2002) was exceeded in water from 11 wells on 

the west side of the valley. Sulfate is the predominant 

anion in water from monitoring wells 17, 20, 24, 25, 

and 33 located south of 6200 South Street on the west 

side. Sulfate dissolved in ground water in the area may 

result from dissolution of gypsum or oxidation of 

pyrite and other sulfide minerals. A sand and gravel 

spit extends from the mountain front eastward into the 

valley at about 6200 South Street, formed by southflowing Lake Bonneville currents that deposited 

sediment from the north end of the Oquirrh Mountains. 

Sediment from streams draining sulfide-mineralized 

rocks in the Bingham Canyon area could have been 

deposited behind the spit in a lower energy 

environment, such as a lagoon. Little natural recharge 

occurs in this area other than from infiltration of 

precipitation because the mountain-front streams are 

ephemeral. Oxidized water recharged from local 

precipitation and the canals could react with the 

sulfide-rich aquifer material and result in dissolved 

sulfate. The primary cation in water from most wells in 

the area is sodium rather than calcium, indicating that 

gypsum dissolution may not be the source of sulfate.

Chloride concentrations in water from the 

monitoring wells ranged from 13 to 456 mg/L and were 

highest in water from wells 2, 4, 6, and 10 in the 

northwestern part of the valley (table 7, appendix). The 

secondary drinking-water regulation of 250 mg/L for 

chloride (U.S. Environmental Protection Agency, 

2002) was exceeded in water from 10 wells, all located 

on the west side of the valley. Water from the Utah and 

Salt Lake Canal (USGS site number 

403524111572202) had a dissolved-solids 

concentration of 832 mg/L, 203 mg/L of which was 

chloride. Monitoring wells 2 and 4 are located near 

faults (fig. 1) and contained water with more than twice 

as much chloride as did water from the canal. Water 

movement along a fault may affect water quality in the 

area.

The inorganic chemical composition of ground 

water largely depends on the type of rocks and 

associated minerals with which it has been in contact. 

Basin-fill deposits in the southeastern part of the valley 

are derived from rocks more resistant to weathering, 

such as quartzite and quartz monzonite. Shallow 

ground water from the monitoring wells on the east 

side of Salt Lake Valley is predominantly a calcium 

bicarbonate type that indicates less reactive aquifer 

material that contains quartz (fig. 7).

Basin-fill deposits on the west side of the valley 

have eroded from more varied rock sources. The 

Oquirrh Mountains are composed of Paleozoic 

carbonate rocks, some of which have undergone sulfide 

mineralization; Tertiary volcanic rocks; and Quaternary 

to Tertiary semiconsolidated alluvial deposits. Sodium, 

calcium, bicarbonate, and chloride are the predominant 

ions in water from monitoring wells 8, 14, and 31. 

These are the westernmost monitoring wells upgradient 

from all or most of the canals, and the chemical 

composition of the ground water is likely controlled by 

reaction with the aquifer material. The predominant 

ions in water from wells completed in the deeper 

aquifer in the area are calcium, chloride, and 

bicarbonate, indicating that water at greater depths has 

undergone similar reactions with the aquifer material.

Seepage from four irrigation canals that divert 

water from the Jordan River is a major source of 

recharge on the west side of the valley, in addition to 

recharge from locally derived precipitation. The Jordan 

River drains Utah Lake, which becomes more 

mineralized by mixing with geothermal water, 

dissolution, and evaporation. Predominant ions in 

water from the Utah and Salt Lake Canal near 

monitoring well 33 are sodium and chloride. Wells 

downgradient from the canals north of 6200 South 

Street contain water that ranges from a sodium 

bicarbonate type to a sodium chloride type and is likely 

a mixture of locally recharged water and seepage from 

the canals.

Trace Elements

Concentrations of the trace elements nickel, 

selenium, antimony, chromium, and barium, analyzed 

for in water from the monitoring wells, were less than 

the MCLs or HALs. Lead, silver, cadmium, and 

beryllium were analyzed for, but not detected. 

Molybdenum, arsenic, uranium, and radon were 

detected in water from some wells at concentrations 

that exceeded MCLs, proposed MCLs, or HALs. The 

lifetime HAL of 40 μg/L for molybdenum (U.S. 

Environmental Protection Agency, 2002) was exceeded 

in water from four monitoring wells (wells 2, 9, 17, and 

29) (table 8, appendix).
Ground-Water Quality 19

EXPLANATION

Utah and Salt Lake Canal

Northwestern part of study area

Southwestern part of study area

Eastern part of study area

PERCENT

CALCIUM

100

80

60

40

200

0

20

40

60

80

100

MAGNESIUM

0

20

40

60

80

100

SODIUM PLUS POTASSIUM

CHLORIDE, FLUORIDE, NITRITE PLUS NITRATE

0

20

40

60

80

100

100

80

60

40

20

0

CARBONATE PLUS BICARBONATE

100

80

60

40

20

0

SULFATE

0

20

40

60

80

100

SULFATE PLUS CHLORIDE

0

20

40

60

80

100

100

CALCIUM PLUS MAGNESIUM

 80

60

40

20

0

100

80

60

40

20

0

PERCENT

PERCENT

Figure 7. Major-ion composition of water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah.
20 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Arsenic concentrations ranged from less than 1 

μg/L in ground water from the east side of Salt Lake 

Valley to almost 20 μg/L in ground water from the west 

side (fig. 8). The median concentration for water from 

the 30 monitoring wells was 7 μg/L (1.1 μg/L for the 

east side of the valley and 11.7 μg/L for the west side). 

Concentrations in water from 12 wells, all of which are 

on the west side of the valley, exceeded the drinking 

water MCL of 10 μg/L (U.S. Environmental Protection 

Agency, 2002).

Water from monitoring wells in the northwestern 

part of the valley generally had higher arsenic 

concentrations than other areas (fig. 8). This may be 

related to more fine-grained deposits, and therefore a 

greater likelihood for reducing conditions, coupled 

with less recharge available to move arsenic through 

the system. The proximity of faults, and the potential 

for geothermal water to move into the basin-fill 

deposits, is also a potential factor for elevated arsenic 

concentrations in the area. Arsenic is present in 

volcanic gases and is a common constituent of 

geothermal water (Hem, 1989, p. 144).

Water in the Utah and Salt Lake Canal, a source 

of recharge to the west side of the valley, had 10 μg/L 

of dissolved arsenic. Iron oxide that adsorbs or contains 

arsenic can be dissolved or reduced through the 

addition of organic carbon, resulting in release of 

arsenic to the ground water (Welch and others, 2000; 

Welch and Lico, 1998). Reddish-orange and black 

staining on sediment particles indicate iron oxide and 

manganese oxide coatings, respectively, and were 

noted in the unsaturated zone while drilling many of 

the west-side monitoring wells. The relatively high 

arsenic concentration and the presence of dissolved 

iron (40 μg/L) and organic carbon (3.2 mg/L) in water 

from well 4 may indicate this process.

Tertiary-age volcanic rocks and the Salt Lake 

Formation exposed near the base of the Oquirrh 

Mountains may be a source of arsenic that is not 

present on the east side of the valley. The Oquirrh 

Mountains consist mainly of Paleozoic-age carbonate 

and quartzite rocks that were intruded by mid-Tertiaryage igneous rocks and associated mineralized fluids in 

the Bingham Canyon area. Basin-fill deposits derived 

from the sulfide mineralized consolidated rocks contain 

arsenic. Oxidation of arsenic-bearing sulfides also can 

release arsenic to ground water. Water from well 20 

had relatively high concentrations of dissolved arsenic 

(17.7 μg/L) and sulfate (1,480 mg/L), possibly as a 

result of sulfide oxidation.

Ground water affected by mining activities of 

sulfide-ore deposits near Bingham Creek had a mean 

arsenic concentration of 14 μg/L (Kennecott Utah 

Copper Environmental Engineering Projects Group, 

written commun., 1998, table 4.9). The processed ore is 

transported to a smelter at the north end of the Oquirrh 

Mountains that may release arsenic to the air and affect 

concentrations in local precipitation. Arsenic 

concentrations averaging 17 μg/L were measured in 

rain and snow collected downwind from a smelter in 

Tacoma, Washington (Crecelius, 1975). Sediment 

cored from Mirror Lake, in the Uinta Mountains about 

50 mi east of Salt Lake City, was enriched in arsenic, 

lead, zinc, copper, tin, and cadmium relative to deeper 

sediments (Kada and others, 1994). The start of largescale mining and smelting of nonferrous metal ores in 

the Salt Lake Valley area corresponds with the increase 

of arsenic in the dated lake sediment.

Radionuclides

Radon occurs naturally as a gas that is soluble in 

ground water and is released through radioactive decay 

from rocks containing uranium (fig. 9). It is the direct 

result of decay of radium-226, a decay product of 

uranium-238. Higher concentrations of radon occur in 

areas with uranium-rich sources such as granite, 

metamorphic rocks, and basin-fill deposits weathered 

from these rocks. Because of a short half-life of 3.8 

days, radon is detected near its source. The radon 

concentration in water is reported in terms of activity 

where 1 pCi/L is about equal to the decay of two atoms 

of radon per minute in a liter of water. Radon moves 

more easily through highly permeable material, such as 

sand, gravel, and fractures, and readily degasses from 

water exposed to air. Breathing radon in indoor air is 

the second leading cause of lung cancer and is a greater 

health concern than drinking water that contains radon 

(U.S. Environmental Protection Agency, 1999). The 

proposed MCL for radon in drinking water is 300 

pCi/L (U.S. Environmental Protection Agency, 2002).

Radon concentrations in water from the 30 

monitoring wells ranged from 243 to 2,190 pCi/L, with 

a median value of 574 pCi/L (table 2). Only water from 

wells 3 and 11, in the northwestern part of the valley, 

had a concentration of less than 300 pCi/L. The median 

concentration for water from monitoring wells on the 

east side of the valley was 719 pCi/L compared to 524 

pCi/L on the west side. Water from wells 22, 32, 37, 

and 41 had radon concentrations greater than 1,000 
Ground-Water Quality 21

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Arsenic concentration in water sampled from monitoring wells, in micrograms per liter

Less than 1

1– 5

5 – 10

10 – 15

15 – 20

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 8. Arsenic concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah.
22 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Radon concentration in water sampled from monitoring wells, in picocuries per liter

243 – 500

500 – 1,000

1,000 – 1,500

1,500 – 2,193

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 9. Radon concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah.
Ground-Water Quality 23

pCi/L. These wells are located on the east side of valley 

where the mountain block is composed of quartzite and 

quartz monzonite.

Uranium dissolved in water from the monitoring 

wells ranged from less than 1 μg/L at well 29 to about 

93 μg/L at well 41, both on the east side of the valley 

(table 8). Uranium is soluble under oxidizing 

conditions, and because of its long half-life (4.5x109

years) can be transported by ground water farther from 

its source areas than can radon. It is concentrated in the 

sediment in reducing environments because of mineral 

precipitation. The lack of detectable uranium in water 

from well 29 is a result of reducing conditions. The 

relatively high uranium concentration in water from 

well 41 may result from its proximity to intrusive rocks 

in the Wasatch Range. The MCL for uranium of 30 

μg/L (U.S. Environmental Protection Agency, 2002) 

was exceeded in water from three wells, all of which 

are on the east side of Salt Lake Valley.

Nutrients and Dissolved Organic Carbon

Although the nutrients nitrogen and phosphorus 

can occur naturally in ground water, elevated 

concentrations in ground water are thought to be 

caused by human activities. Some of the potential 

sources of nutrients in ground water include fertilizers 

applied to lawns and gardens and leaking or improperly 

functioning septic systems and sewer pipes. Nitrogen 

compounds such as ammonia and ammonium 

fertilizers naturally transform into nitrate, which is 

relatively stable in oxygenated subsurface 

environments and is readily transported in water. 

Nitrite is unstable in aerated water and is seldom 

present in measurable concentrations under oxidizing 

conditions. In this report, nitrate is reported as the sum 

of nitrite and nitrate as nitrogen.

Background nitrate concentrations in ground 

water from areas not associated with agricultural 

practices commonly are less than 2 to 3 mg/L as 

nitrogen (Halberg and Keeney, 1993) and 

concentrations greater than 2 mg/L may indicate 

ground water affected by human activities (U.S. 

Geological Survey, 1999). Some existing nitrate data 

for ground water in the Great Salt Lake Basins study 

area are available from the USGS National Water 

Information System (NWIS) database. In 

urban/residential areas, the median nitrate 

concentration in water from wells less than 150 ft deep 

was 1.1 mg/L (71 analyses); in water from wells 

greater than 150 ft deep, generally completed in the 

deeper unconfined aquifers, it was less than 1 mg/L 

(110 analyses).

Nitrate concentration in water sampled from 26 

of the 30 monitoring wells (86.7 percent) was higher 

than an assumed background level of 2 mg/L, 

indicating a possible human influence. Concentrations 

ranged from less than 0.05 to 13.3 mg/L with a median 

concentration of 6.85 mg/L for the 30 samples (table 9, 

appendix). The median nitrate concentration for water 

from monitoring wells on the east side of the valley 

was 4.45 mg/L compared to 7.05 mg/L on the west side 

(fig. 10). The MCL of 10 mg/L for nitrate in drinking 

water (U.S. Environmental Protection Agency, 2002) 

was exceeded in water from wells 11, 17, and 37. 

Concentrations of nitrite, ammonia, ammonia 

plus organic nitrogen, phosphorus, and 

orthophosphorus in water from the monitoring wells 

were low, 2 to 3 orders of magnitude less than MCLs or 

health advisory levels. Nitrite was detected in water 

from 5 of the 30 wells, 3 of which had other indicators 

of reducing conditions. The presence of nitrite in water 

from four of the wells corresponded to nitrate 

concentrations greater than 7.5 mg/L. Ammonia 

detected in seven ground-water samples may be the 

result of sample contamination because ground-water 

concentrations were only slightly greater than those 

measured in a field-blank sample. Water from four of 

the wells had phosphorus concentrations greater than 

0.1 mg/L, and two of those also had the highest nitrate 

concentrations (wells 17 and 37). Water from these 

wells likely has been affected by anthropogenic factors 

such as sewer lines, septic tanks, confined animals, or 

fertilizers.

DOC can affect ground-water quality because it 

is involved in oxidation/reduction reactions with 

chemical constituents of the aquifer material and 

ground water. The median DOC concentration in water 

from the monitoring wells was 1.5 mg/L and ranged 

from 0.60 mg/L at well 26S to 4.6 mg/L at well 1 (table 

9, appendix). DOC measured in water from six fieldblank samples (median concentration of 0.96 mg/L) is 

attributed to contamination introduced from the 

sampling equipment cleaning procedure. Rinsing of the 

sampling equipment with ground water during the 

purge cycle likely reduces DOC contamination, but 

some of the DOC measured in water from the wells 

may be from the sampling equipment.
24 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Nitrate concentration in water sampled from monitoring wells, in milligrams per liter

Less than 0.05

0.2 – 3.0

3.0 – 5.0

5.0 – 10.0

10.0 – 13.3

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 10. Nitrate concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake 

Valley, Utah.
Ground-Water Quality 25

Pesticides

Fifteen of the 104 pesticides and pesticide 

degradation products analyzed for were detected in 1 or 

more water samples collected as part of this study 

(table 3 and fig. 11). Breakdown products of pesticides 

(metabolites or degradates) are formed through the 

metabolic degradation of a parent compound. All of the 

pesticides analyzed as part of this study are listed in 

table 10 (appendix). Most are used as herbicides. The 

insecticides diazinon and malathion were detected in 

trace amounts in one sample each. At least one 

pesticide or pesticide degradation product was detected 

in water from 28 of the 30 monitoring wells. The two 

wells with no pesticide detections are located on the 

east side of the valley (wells 32 and 37). Water from 

well 7 on the west side of the valley contained 10 

different pesticide compounds, including bromacil, 

diuron, atrazine, and atrazine degradation products, all 

herbicides used to control roadside vegetation. No 

pesticides were detected at concentrations that 

exceeded USEPA drinking-water standards or 

guidelines (U.S. Environmental Protection Agency, 

2002).

Much lower analytical reporting levels were used 

in this study than are typically used in routine pesticide 

monitoring of public-water supplies. Therefore, much 

higher rates of detection were obtained than would 

have been possible with less sensitive analytical 

methods. The MRL for atrazine is 0.001 μg/L, about 

ATRAZINE

BROMACIL

DEETHYLATRAZINE

DEIA

DEISOPROPYLATRAZINE

2-HYDROXYATRAZINE

CAFFEINE

DIAZINON

DIURON

MALATHION

P,P' DDE

PICLORAM

PROMETON

SIMAZINE

TEBUTHIURON

0

10

20

30

40

50

60

70

80

90

100

FREQUENCY OF DETECTION, IN PERCENT

Figure 11. Detection frequency of pesticides in water sampled from monitoring wells in areas of recent residential development, Salt Lake 

Valley, Utah.
26 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

two orders of magnitude lower than that used on water 

from drinking-water wells for the USEPA's National 

Pesticide Survey done in 1988-90 (Barbash and others, 

1999).

Water-quality standards are based on 

concentrations of individual pesticides and do not 

account for mixtures of pesticides. Total concentration 

of pesticides and pesticide degradation products in 

water ranged from an estimated 0.002 μg/L at well 22 

(diazinon) to 2.56 μg/L at well 11 (a mixture of 

atrazine, atrazine degradation products, and simazine). 

The effects of different combinations of pesticides on 

human health are not known at this time; therefore, 

drinking-water standards have not been set for 

pesticide mixtures.

The herbicide atrazine and its degradation 

product deethylatrazine (DEA) were the most 

frequently detected pesticides in the study, detected in 

23 and 21 of the 30 water samples, respectively. All but 

one of the water samples from the west side of the 

valley contained detectable concentrations of atrazine 

(well 14). Atrazine concentrations in water from the 30 

monitoring wells ranged from less than 0.001 to 1.58 

μg/L (table 11, appendix), all below the MCL for 

atrazine in drinking water of 3 μg/L (U.S. 

Environmental Protection Agency, 2002) (fig. 12). 

Atrazine is a restricted-use pesticide that is 

generally used on corn and along roads, railroads, other 

right-of-ways, utility substations, and industrial lots to 

control weeds and undesired vegetation in the valley 

(Mark Quilter, Utah Department of Agriculture and 

CONCENTRATION, IN MICROGRAMS PER LITER

Detection

Minimum reporting level

Maximum Contaminant Level (MCL)

Lifetime Health Advisory Level (HAL)

EXPLANATION

ATRAZINE

BROMACIL

DEETHYLATRAZINE

DEIA

DEISOPROPYLATRAZINE

2-HYDROXYATRAZINE

CAFFEINE

DIAZINON

DIURON

MALATHION

P,P' DDE

PICLORAM

PROMETON

SIMAZINE

TEBUTHIURON

HAL=90 HAL=100 MCL=500 HAL=100 HAL=500

0.001

0.01

0.1

1

10

Figure 12. Concentration of selected pesticides in water sampled from monitoring wells in areas of recent residential development, Salt 

Lake Valley, Utah.
Ground-Water Quality 27

Food, oral commun., 2000). It is not for household use. 

The high detection frequency of atrazine in residential 

areas on the west side may be the result of application 

in agricultural or industrial areas that have been 

converted to residential uses or application in areas 

upgradient from the residential areas that was then 

transported by ground water. The presence of atrazine 

and other pesticides in ground water is likely the result 

of widespread use rather than small-scale point sources 

such as spills. Atrazine probably is transported to the 

ground-water system by direct sources of recharge, 

such as seepage from drainage systems and retention 

basins.

Degradation products of atrazine other than DEA 

that were detected include deisopropylatrazine, 

deethyldeisopropylatrazine (DEIA), and 2-

hydroxyatrazine. Deisopropylatrazine can form from 

the degradation of either atrazine or simazine. The total 

concentration of atrazine and its degradation products 

in the 30 water samples ranged from not detected at six 

wells on the east side of the valley to 2.54 μg/L at well 

11 on the west side (fig. 13). At least one of these 

compounds was detected in water from all 19 wells 

located on the west side of Salt Lake Valley. None of 

the cumulative concentrations of atrazine and its 

degradation products were greater than 0.1 μg/L in 

water sampled from the east side of the valley, whereas 

12 of the samples from the west side contained more 

than 0.1 μg/L.

Prometon was the third most frequently detected 

pesticide, detected in water sampled from 15 wells (50 

percent), including 6 of the 11 samples collected from 

wells on the east side of the valley (fig. 14). The 

maximum concentration of 0.518 μg/L in water from 

well 1 is much less than the HAL for drinking water of 

100 μg/L (U.S. Environmental Protection Agency, 

2002). Prometon is registered for use by homeowners 

to control vegetation and generally is used along rightsof-way (Mark Quilter, Utah Department of Agriculture 

and Food, oral commun., 2000). It also can be used in 

and under asphalt to prevent weeds from emerging 

through it (Ciba-Geigy Corporation, 1994). Nationally, 

it was the most frequently detected herbicide in ground 

water at urban sites sampled as part of the NAWQA 

program (Capel and others, 1999). Its more frequent 

occurrence on the east side of the valley relative to 

atrazine and simazine may reflect greater usage in 

residential areas.

Simazine was detected in water sampled from 13 

wells (43.3 percent) with a maximum concentration of 

0.027 μg/L in well 1, well below the MCL of 4 μg/L 

(U.S. Environmental Protection Agency, 2002). 

Simazine is commonly used as weed control for corn 

fields and orchards, on rights-of-way, and utility 

substations (Mark Quilter, Utah Department of 

Agriculture and Food, oral commun., 2000). All but 

one of the detections were in water from wells on the 

west side of the valley.

Tebuthiuron was detected in water sampled from 

4 wells (13.3 percent) with a maximum concentration 

of 0.120 μg/L in water from well 2, far below the longterm HAL of 500 μg/L (U.S. Environmental Protection 

Agency, 2002). It is used along rights-of-way and to 

control sagebrush and weeds in noncrop areas of the 

valley (Mark Quilter, Utah Department of Agriculture 

and Food, oral commun., 2000). Tebuthiuron was 

detected in water from wells 18 and 41 on the east side 

of the valley in addition to prometon.

Concentrations of atrazine, simazine, prometon, 

malathion, and diazinon in water samples collected 

from Little Cottonwood Creek near the Jordan River in 

Salt Lake Valley increased during storm events 

(Gerner, 2003). Although this site is in a ground-water 

discharge area and is surrounded by more industrial 

land use than the residential study area, it indicates that 

pesticides can be concentrated in stormwater runoff. 

Runoff that flows to potential sources of recharge such 

as canals or retention basins in the primary or 

secondary recharge areas may also transport 

anthropogenic compounds that have been washed from 

the land surface to the shallow ground-water system.

Volatile Organic Compounds

VOCs are carbon-containing chemicals that 

readily evaporate at normal air temperature and 

pressure. They are contained in many manufactured 

products such as gasoline, paints, adhesives, solvents, 

wood preservatives, dry-cleaning agents, pesticides, 

fertilizers, cosmetics, and refrigerants. Potential 

sources of VOCs to ground water are direct industrial 

and wastewater discharges, infiltration of spills, leaking 

underground storage tanks, stormwater runoff, and 

atmospheric deposition of vehicle and industrial 

emissions. Many VOCs are used in and around the 

home and can enter the ground-water system through 

spills, storm drains, septic systems, and leaking sewer 
28 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Total concentration of atrazine and its degradation products in

water sampled from monitoring wells, in micrograms per liter

Not detected

0.004 – 0.010

0.010 – 0.100

0.100 – 1.00

1.00 – 2.54

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 13. Total concentration of atrazine and its degradation products in water sampled from monitoring wells in areas of recent residential 

development, Salt Lake Valley, Utah.
Ground-Water Quality 29

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Prometon concentration in water sampled from monitoring wells,

in micrograms per liter

Not detected

0.004 – 0.010

0.010 – 0.100

0.100 – 0.500

0.500 – 0.518

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 14. Prometon concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah.
30 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

lines. The U.S. Environmental Protection Agency 

(2002) has established MCLs in drinking water for 

more than 20 VOCs because of human health concerns.

Fifteen of the 86 VOCs analyzed for were 

detected in 1 or more water samples collected as part of 

this study (table 4). All of the VOCs analyzed for as 

part of this study are listed in table 12 (appendix). 

Detection of many VOCs is the result of improved 

analytical methods that allow measurement of lower 

concentrations (Conner and others, 1998). The most 

frequently detected VOCs were chloroform (90 

percent), bromodichloromethane (56.7 percent), 

tetrachloroethylene (53.3 percent), and 1,1,1-

trichloroethane (50 percent) (fig. 15). 

Chloroform and bromodichloromethane were 

detected in water from 27 and 17 wells, respectively 

(fig. 16). Generally, these compounds are byproducts of 

chlorinated ground and surface water that has reacted 

with organic material in the water and aquifer material, 

and are part of a group of VOCs known as 

trihalomethanes (THMs). These disinfection 

byproducts are regulated by the USEPA as total THMs 

with a cumulative MCL of 80 μg/L (U.S. 

Environmental Protection Agency, 2002). The 

widespread occurrence of chloroform and 

bromodichloromethane in shallow ground water is 

likely a result of the recharge of chlorinated publicsupply water used to irrigate lawns and gardens in 

residential areas of Salt Lake Valley. Water disinfected 

0

10

20

30

40

50

60

70

80

90

100

FREQUENCY OF DETECTION, IN PERCENT

BROMODICHLOROMETHANE

CARBON DISULFIDE

CHLOROFORM

CHLOROMETHANE

1,1-DICHLOROETHANE

1,2-DICHLOROETHANE

1,1-DICHLOROETHYLENE

DICHLOROMETHANE

TETRACHLOROMETHANE

1,1,1-TRICHLOROETHANE

TRICHLOROETHYLENE

TRICHLOROFLUOROMETHANE

1,1,2-TRICHLOROTRIFLUORETHANE

METHYL TERT-BUTYL ETHER

TETRACHLOROETHYLENE

Figure 15. Detection frequency of volatile organic compounds in water sampled from monitoring wells in areas of recent residential 

development, Salt Lake Valley, Utah.
Ground-Water Quality 31

for public supply also can enter the ground-water 

system through leaking swimming pools, water lines, 

sewer lines, and septic systems.

Chloroform concentrations ranged from an 

estimated 0.03 μg/L to 2.41 μg/L (table 13), much less 

than the MCL for total THMs. Chloroform detected in 

monitoring wells is an indication that water treated for 

public supply is recharging the shallow ground-water 

system (fig. 17). The median chloroform concentration 

in water from the 30 monitoring wells was 0.28 μg/L, 

0.19 μg/L in water from 11 wells on the east side, and 

0.55 μg/L in water from 19 wells on the west side of the 

valley. 

Tetrachloroethylene (tetrachloroethene, 

perchloroethylene, PCE), primarily used as a dry 

cleaning agent and solvent, was detected in water from 

16 wells (fig. 18). Although the median concentration 

for the 30 samples was less than the LRL of 0.1 μg/L, 

water from 4 wells in the northwestern part of the 

valley had concentrations greater than 1 μg/L (wells 1, 

5, 8, and 9; table 13, appendix). The maximum PCE 

concentration detected in water from the monitoring 

wells in 1999 was 7.8 μg/L (well 5), which is greater 

than the MCL of 5 μg/L for drinking water (U.S. 

Environmental Protection Agency, 2002).

Detection

Minimum reporting level

Maximum Contaminant Level (MCL)

Lifetime Health Advisory Level (HAL)

EXPLANATION

BROMODICHLOROMETHANE

CARBON DISULFIDE

CHLOROFORM

CHLOROMETHANE

1,1-DICHLOROETHANE

1,2-DICHLOROETHANE

1,1-DICHLOROETHYLENE

DICHLOROMETHANE

TETRACHLOROMETHANE

1,1,1-TRICHLOROETHANE

TRICHLOROETHYLENE

TRICHLOROFLUOROMETHANE

1,1,2-TRICHLOROTRIFLUORETHANE

METHYL TERT-BUTYL ETHER

TETRACHLOROETHYLENE

CONCENTRATION, IN MICROGRAMS PER LITER

0.001

0.01

0.1

1

100

10

MCL=200 HAL=2,000

Figure 16. Concentration of selected volatile organic compounds in water sampled from monitoring wells in areas of recent residential 

development, Salt Lake Valley, Utah.
32 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Base from U.S. Geological Survey digital line graph data, 1:100,000, 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Chloroform concentration in water sampled from monitoring wells,

in micrograms per liter

Not detected

0.03 – 0.10

0.10 – 0.50

0.50 – 1.00

1.00 – 2.41

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 17. Chloroform concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake Valley, Utah.
Ground-Water Quality 33

Base from U.S. Geological Survey digital line graph data, 1:100,000 , 1979 and 1980

Universal Transverse Mercator projection, Zone 12

Tailings ponds

40r30'

40r45'

Jordan River

0 3 6 KILOMETERS

0 3 6 MILES

West

Valley

City

Salt

Lake

City

South

Jordan

West

Jordan

Murray

Sandy

Draper

Riverton

EXPLANATION

Area of recent residential and commercial land use

Discharge area

Primary recharge area

Secondary recharge area

Approximate boundary of basin-fill deposits in Salt Lake Valley

Tetrachloroethylene concentration in water sampled from monitoring wells, in micrograms per liter

Not detected

Detected – 0.1

0.1 – 1.0

1.0 – 5.0

5.0 – 7.8

112r07'30" 111r48'

SALT LAKE COUNTY

UTAH COUNTY

Figure 18. Tetrachloroethylene (PCE) concentration in water sampled from monitoring wells in areas of recent residential development, Salt Lake 

Valley, Utah.
34 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Resampling of well 27 on the east side of the 

valley showed an increase in PCE concentration from 

0.8 μg/L in 1999 to 2.5 μg/L in 2000, and to 10.0 μg/L 

in 2001. The increase in PCE concentration is an 

indication of ground water moving past the well from 

an upgradient source. Seasonal sampling of well 27 in 

2000 showed a higher PCE concentration in June (6.0 

μg/L) than in September (2.5 μg/L). Chloroform 

concentration also was higher in June (4.52 μg/L) as 

compared to September (2.03 μg/L). Water levels in 

well 27 fluctuated from 57.14 ft below land surface in 

November 1999 to 60.33 ft in June 2001 and are likely 

related to water applied to lawns and fields during the 

summer in the area that recharges the shallow aquifer. 

The water level in the well generally rises from JuneJuly until November and then falls from December 

until May-June. The higher PCE and chloroform 

concentrations in June may correspond with a 

reduction in recharge occurring in the winter and, 

therefore, less dilution of the contaminant plume.

Trichloroethylene (trichloroethene, TCE) is used 

mainly as a solvent, metal degreaser, and drying agent. 

Trichloroethylene was detected in water from five wells 

with concentrations ranging from an estimated 0.02 

μg/L (well 10) to 1.54 μg/L (well 2), less than the MCL 

of 5 μg/L (U.S. Environmental Protection Agency, 

2002). An additional source of TCE can be the 

degradation of PCE under reducing conditions. Water 

from the five wells with TCE also contained PCE; 

reducing conditions were present in water from only 

three of these wells. Trichloroethylene concentration in 

water sampled from well 5 increased from an estimated 

0.06 μg/L in 1999 to 0.08 μg/L in 2000, and to 0.10 

μg/L in 2001, and PCE concentration remained above 7 

μg/L. The increase in TCE may indicate degradation of 

PCE or movement of water from a different 

contaminant plume to the well.

1,1,1-trichloroethane (methyl chloroform, TCA) 

was detected in water from 15 wells at concentrations 

ranging from an estimated 0.01 μg/L to 0.22 μg/L 

(table 13, appendix). It is generally used as a solvent 

and has an MCL of 200 μg/L (U.S. Environmental 

Protection Agency, 2002). 1,1,1-trichloroethane was 

detected in the atmosphere at concentrations greater 

than 0.05 μg/L in 84 percent of the air samples 

collected in an urban/residential area of New Jersey, 

but these concentrations correspond to concentrations 

in water of less than 0.002 μg/L (Baehr and others, 

1999). Because of the widespread occurrence of TCA 

in shallow ground water in Salt Lake Valley at 

concentrations greater than assumed for atmospheric 

deposition, its presence in ground water is likely the 

result of activities at the land surface. TCA can degrade 

to dichloroethylene (DCE) under reducing conditions. 

Both compounds were detected in water from well 2 

and, although a dissolved oxygen concentration 

indicative of reducing conditions was not measured, 

degradation of TCA may be occurring along the flow 

path.

The VOCs derived from gasoline were detected 

in five ground-water samples at concentrations lower 

than those estimated in the field-blank samples. 

Benzene; ethylbenzene; 1,2,4-trimethylbenzene; and 

m- and p-xylene were detected in water from wells 32 

and 34 and may be from exhaust from the gasolinepowered generator used during sampling or from 

passing vehicles. These detections were not used in the 

VOC data analysis. 

Methyl tert-butyl ether (MTBE) was detected at 

an estimated concentration of 0.1 μg/L, near the LRL, 

in water from well 27 with no other gasoline-derived 

VOCs detected. This compound is used to oxygenate 

gasoline to improve combustion and reduce air-quality 

degradation. Because of the high solubility of MTBE in 

water, atmospheric washout in urban areas may be the 

source of low concentrations in ground water 

(Squillace and others, 1996). No MTBE was detected 

during resampling of water from well 27 in 2000 and 

2001.

Urban stormwater runoff that flushes spills off of 

the land surface may be a source of certain VOCs in 

shallow ground water. Many of the same VOCs, such 

as PCE and TCE, were commonly detected in both 

stormwater and shallow ground water from urban areas 

across the United States (Lopes and Bender, 1998). 

Elevated concentrations of gasoline-related compounds 

(1,2,4-trimethylbenzene, xylene, and toluene) and TCE 

were measured during storm events in water sampled 

from Little Cottonwood Creek near the Jordan River 

(Gerner, 2003). Stormwater runoff that flows through 

or is retained in the primary or secondary recharge 

areas can recharge the shallow ground-water system 

along with any anthropogenic compounds that have 

been washed from the land surface.
Sources of Ground-Water Recharge 35

SOURCES OF GROUND-WATER RECHARGE

Environmental tracers were used to determine 

the sources of recharge to the shallow ground-water 

system in recently developed residential areas in the 

valley. The stable isotopes of water, deuterium, and 

oxygen-18 were used to differentiate between local 

precipitation and water that had been subjected to evaporation. Tritium, helium-3, and chlorofluorocarbons in 

the water were used to identify and approximately date 

ground water recharged within the past 50 years.

Stable Isotopes

The stable isotopes of water, deuterium (D or 

2H) and oxygen-18 (18O), can be used to determine 

recharge sources because they generally are 

conservative once they enter shallow ground-water 

systems. Small amounts of 2H and 18O are 

incorporated into the water molecule in average 

proportions of about 0.01 percent and 0.2 percent, 

respectively (Hem, 1989, p. 162). Oxygen and 

hydrogen isotope ratios, expressed as delta (δ) 18O or 

δ2H, are reported in parts per thousand (per mil) 

deviations from a reference standard called Vienna 

Standard Mean Ocean Water (VSMOW) (Coplen and 

others, 2000). Water with more negative per mil values 

has less 18O and 2H relative to 16O and H, respectively, 

and is lighter than water with less negative per mil 

values (heavier δ18O or δ2H values). The relation 

between δ18O and δ2H in precipitation is generally 

expressed by the equation δ2H = 8δ18O + 10, known as 

the global meteoric water line (Craig, 1961). Ground 

water has an isotopic signature that is indicative of 

conditions at the time of recharge because 18O and 2H 

are generally conservative. Mixing with other recharge 

sources can alter this isotopic signature.

Values of δ18O or δ2H for water from most of the 

monitoring wells (table 5) plot off of the global 

meteoric water line because of evaporation (fig. 19). A 

line with a less steep slope can be drawn through water 

sampled from mountain-front streams, from the Jordan 

River at different sites and times of the year, and from 

canals that divert water from the Jordan River (fig. 19). 

Water from the mountain-front streams typically 

represents water that has not undergone evaporation, 

whereas water from canals diverted from the Jordan 

River has undergone evaporation. Precipitation 

occurring at lower altitudes, such as on the valley floor, 

likely plots higher on the global meteoric water line, 

with some offset as a result of evaporation, than does 

water from the mountain-front streams. Stable isotope 

ratios for water from the monitoring wells plot near a 

mixing line connecting the recharge sources of 

precipitation and evaporated diversion water. Ground 

water from the monitoring wells is a mixture of varying 

amounts of local precipitation and evaporated water, on 

the basis of stable isotope ratios.

Precipitation on the Wasatch Range and the 

Oquirrh Mountains is represented isotopically by 

samples from streams draining the mountains where 

they enter the valley. This water is isotopically light 

because the precipitation fell at higher altitudes and at 

colder temperatures than did precipitation at the valley 

floor. Stable isotope ratios for water from monitoring 

wells 26S, 26D, and 29 near Little Cottonwood Creek 

are similar to those for water from the creek at 

Crestwood Park (USGS streamflow-gaging station 

10167800) (fig. 19). This similarity indicates that 

seepage from Little Cottonwood Creek is a source of 

recharge to the shallow ground-water system in the 

area.

Because of evaporation, canal water diverted 

from the Jordan River and used for irrigation is heavier 

in 2H and 18O relative to precipitation occurring locally 

or on the adjacent mountains. Evaporated water can 

recharge the shallow ground-water system through 

seepage and infiltration of unconsumed irrigation 

water. Water from wells 3, 7, and 11 on the west side of 

the valley is the heaviest in 2H and 18O of the 30 

monitoring wells. Isotopic concentrations in local 

precipitation are probably represented by water from 

wells 8, 14, and 31, which are upgradient from most of 

the canals on the west side of the valley. Water from the 

Utah and Salt Lake Canal in the southwestern part of 

the valley is much heavier isotopically because of 

evaporation. Water from wells 3, 7, and 11 plot about 

two-thirds of the way between the two potential 

sources of recharge—water represented by wells 8, 14, 

and 31 and water from the Utah and Salt Lake Canal 

(fig. 19). As a result, about two-thirds of the water from 

these wells is recharged from area canals if local 

precipitation and canal water are the primary sources of 

recharge.
36 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Because the monitoring wells are located in 

residential areas, a potential source of recharge to the 

shallow ground-water system is water used for public 

supply. Public-supply water in Salt Lake Valley is 

primarily from mountain-front streams and from the 

principal aquifer and is used to irrigate lawns and 

gardens. Stable isotope ratios for ground water from 

the principal aquifer on the east side of Salt Lake 

Valley are similar to those for water from the mountainfront streams, which indicates that precipitation 

originating at higher altitudes is a main source of 

recharge (Thiros, 1995). Water supplied to the public 

may undergo some evaporation during lawn and garden 

irrigation and other household uses before it infiltrates 

into the ground. Wells 22, 32, 37, and 39 on the east 

side of the valley are upgradient from canals diverted 

from the Jordan River, but contain a component of 

evaporated water on the basis of stable isotope ratios 

(fig. 19). Chloroform was detected in water from these 

Table 5. Stable isotope ratio, tritium concentration, and apparent age for water sampled from 30 monitoring wells in areas of recent residential 

development, Salt Lake Valley, Utah

[Well identifier, see figure 3 for well location; per mil, parts per thousand; TU, tritium units; —, no data; Contaminated, concentration greater than what was 

possible for equilibrium with the atmosphere; Modern, within the possible range of modern air; >, greater than]

Well 

identifier

Well depth 

(feet)

Delta 

oxygen-18

Delta 

deuterium Tritium Tritium error

Tritium/

Helium-3 

apparent age

1CFC-11 

apparent age

2CFC-12 

apparent age

3CFC-113 

apparent age

(per mil) (TU) Years

1 48.5 -108.21 -13.73 10.23 0.51 — Contaminated Contaminated Modern

2 38.5 -102.38 -13.02 12.28 .61 13 Contaminated Contaminated Contaminated

3 113.5 -92.09 -10.88 11.01 .56 11 Contaminated Contaminated Contaminated

4 38.5 -114.70 -14.90 1.67 .08 38 Contaminated Contaminated Modern

5 43.5 -109.15 -13.69 12.41 .62 11 Contaminated Contaminated 11

6 38.5 -96.46 -11.58 11.83 .59 3 Contaminated Contaminated —

7 43.5 -92.11 -10.94 14.03 .70 — Contaminated Contaminated 11

8 67.5 -112.36 -14.38 14.77 .74 4 Contaminated Contaminated Contaminated

9 38.5 -105.88 -13.19 11.67 .58 13 Contaminated Contaminated 10

10 83.5 -97.32 -11.78 16.60 .85 8 Contaminated Contaminated Contaminated

11 83.5 -93.31 -10.84 10.81 .54 — Contaminated Contaminated Contaminated

14 48.5 -111.92 -14.61 8.00 .40 6 Contaminated Contaminated Contaminated

17 38.5 -98.31 -12.01 11.34 .57 12 21 Contaminated 23

18 106 -112.04 -14.99 10.50 .50 4 Contaminated Contaminated Contaminated

20 92.5 -104.24 -13.26 19.70 .99 — Contaminated Contaminated 12

22 36 -113.66 -14.89 19.67 .98 24 Contaminated Contaminated 10

24 123.5 -98.03 -11.93 20.30 1.01 8 Contaminated Contaminated 10

25 68.5 -98.00 -11.86 18.92 .95 8 Contaminated Contaminated Contaminated

26D 77.5 -118.96 -16.30 12.42 .62 — Contaminated Contaminated Modern

26S 31 -115.92 -15.98 13.25 .66 0 Modern Modern 10

27 73.5 -110.24 -14.42 10.43 .52 3 Contaminated Contaminated Contaminated

29 34 -118.98 -16.42 54.76 2.74 32 48 26 > 44

30 68.5 -100.23 -12.61 11.56 .58 1 Contaminated Contaminated Contaminated

31 153.5 -112.42 -14.25 17.79 .89 1 Contaminated Contaminated 8

32 88.5 -111.23 -14.76 8.89 .44 6 Contaminated Contaminated 12

33 96 -102.12 -12.71 19.30 .96 15 Contaminated Contaminated Contaminated

34 77.5 -105.30 -13.80 2.84 .42 — Contaminated Contaminated Modern

37 73 -112.19 -14.77 23.96 1.20 38 Contaminated Contaminated 14

39 106 -114.59 -15.02 9.39 .47 0 Contaminated Contaminated Modern

41 23 — — 13.19 .66 0 Contaminated Contaminated 9

1 Trichlorofluoromethane.

2 Dichlorodifluoromethane.

3 1,1,2-Trichlorotrifluoroethane.
Sources of Ground-Water Recharge 37

wells; thus, the water is likely a mixture of infiltration 

from local precipitation and seepage of public-supply 

water used for irrigation. 

Seasonal measurements of δ18O and δ2H were 

taken from water in monitoring wells 26S, 26D, 27, 

and 32. Seasonal samples also were collected from a 

38.5-ft-deep monitoring well about 1,270 ft 

downgradient from well 32 in a sprinkler-irrigated field 

of grass, and from Little Cottonwood Creek at 

Crestwood Park (USGS streamflow-gaging station 

10167800) (fig. 20). These wells are on the east side of 

the valley near the mouth of Little Cottonwood Canyon 

where the unconsolidated basin fill is made up 

primarily of permeable deltaic deposits from the 

mountain front. Wells 26S and 26D are next to Little 

Cottonwood Creek, and water from well 26S shows the 

greatest variation in stable isotope ratios with time, 

generally following changes in streamflow in the creek. 

Peak snowmelt runoff in the creek occurs in June with 

lighter δ18O and δ2H values that represent higheraltitude precipitation. Some of this water recharges the 

shallow ground-water system monitored by well 26S, 

which is indicated by lighter isotopic ratios measured 

in ground water sampled in May as compared to other 

times of the year. Water temperature and water level in 

wells 26S and 26D fluctuate in a similar fashion. 

Delta deuterium and δ18O values in water from 

Little Cottonwood Creek at Crestwood Park measured 

in March, April, and August are heavier than those 

measured in June and may represent the effects of 

Local evaporation line

Global meteoric water line

-140

-135

-130

-125

-120

-115

-110

-105

-100

-95

-90

-85

-80

-75

Mountain-front streams, 1990–91

Little Cottonwood Creek at U.S. Geological Survey

streamflow-gaging station 10167800, 2000–01

Red Butte Creek, 1984-87, 1990

Jordan River at various sites, 1990–91

Jordan River at 1700 South Street, 1984–87

Canal diverted from the Jordan River

Monitoring wells in recently developed residential

areas, 1999; see figure 3 for well location

DELTA DEUTERIUM, IN PER MIL

DELTA OXYGEN-18, IN PER MIL

-18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8

East Jordan Canal

Utah and

Salt Lake

Canal

29

26D

26S 39

4

22

18

37

32

14

8 31

27 5

1

34 20

9

2

33

30

17 24

25

10

6

7 3

11

Figure 19. Relation between delta deuterium and delta oxygen-18 for shallow ground-water and surface-water samples from Salt Lake Valley, 

Utah.
38 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

evaporation of stream water, local sources of recharge, 

and (or) shallow ground-water discharge. Water from 

four public-supply wells completed in the principal 

aquifer in the area has a range in δ18O and δ2H values 

similar to that of water from Little Cottonwood Creek 

(fig. 20). 

Delta deuterium and δ18O values for water from 

well 32 did not vary as much with time as did water 

from well 26S because the well is farther away from 

seasonal recharge sources and has a greater depth to the 

water table. Recharge of sprinkler-irrigation water to 

the shallow system was observed isotopically in the 

38.5-ft deep monitoring well near well 32. The water 

level measured in the well during 2000-2001 fluctuated 

from a high of 23.30 ft below land surface in October 

(after the irrigation season) to a low of 26.33 ft in April 

(before the irrigation season). Stable isotope ratios 

were heaviest in the summer when water was applied to 

the area upgradient from the monitoring well and 

became lighter in the winter and spring when no 

irrigation occurred (fig. 20). Water from well 27 

showed a similar seasonal variation. 

Tritium and Tritium/Helium-3

Water from the 30 monitoring wells was 

analyzed for tritium to determine apparent age (table 

5). Tritium is a radioactive isotope of hydrogen (3H) 

with a half-life of 12.43 years. Large quantities of 

tritium were added to the atmosphere from above 

ground thermonuclear testing beginning about 1952 

and provide a marker for precipitation from the testing 

period. Concentrations in precipitation prior to 

atmospheric thermonuclear testing have been estimated 

to be 3 to 6 TU (Kaufmann and Libby, 1954). Tritium 

concentration in water recharged to the basin-fill 

deposits prior to 1952, assuming no mixing with other 

May

June

August

August April

September

September

March

December

December

September

March

August

August

September

September

March

April

May

June

December April

Global meteoric water line

-125

-120

-115

-110

-105

-17 -16 -15 -14 -13

DELTA OXYGEN-18, IN PER MIL

DELTA DEUTERIUM, IN PER MIL

Little Cottonwood Creek at U.S. Geological Survey

streamflow-gaging station 10167800

Wells completed in principal aquifer in area

Well 26S

Well 26D

Well 27

Monitoring well in sprinkler-irrigated field

Well 32

Figure 20. Relation between delta deuterium and delta oxygen-18 for water samples from selected wells and from Little Cottonwood Creek, 

Salt Lake Valley, Utah.
Sources of Ground-Water Recharge 39

sources, would have decayed to less than 1 TU by 1999 

and resulted in about a 50-year timescale. The amount 

of tritium in precipitation collected in Vienna, Austria, 

in 1999 varied from 8.0 TU in December to 17.3 TU in 

June (International Atomic Energy Agency, 2001) and 

is gradually decreasing toward pre-1952 levels. 

Concentrations greater than that of present day indicate 

that the water or a component of the water has been 

recharged since 1952.

Tritium decays to the noble gas helium-3 (3He), 

the stable isotope of helium. The ratio of 3H to 3He 

derived from 3H decay in a water sample can be used to 

determine the time from when water containing 3H 

became isolated from the atmosphere (ground-water 

age). The 3H/3He dating method requires quantification 

of 3He from 3H by accounting for 3He from other 

sources (Solomon and Cook, 2000). The 3H/3He clock 

does not start until water is below the water table and 

completely isolated from the gas phase because 

tritiogenic 3He generated in the unsaturated zone is 

effectively lost to the atmosphere and is not measured 

in the water sample, resulting in younger ages 

determined by the method. Uncertainty in age because 

of analytical uncertainty is approximately ± 0.5 year. 

Larger uncertainties in age can result because of the 

variable tritium input with time, mixing caused by 

dispersion, and losses to the gas phase at the water 

table. Because of the variable nature of the 3H input 

and dispersive mixing, 3H/3He dating is less certain for 

waters older than the mid-1960s bomb pulse.

Tritium concentrations greater than 1 TU in 

water from all of the monitoring wells (table 5) confirm 

a component of recharge to the shallow ground-water 

system after atmospheric thermonuclear testing began 

in 1952. Water from most of the wells had a tritium 

concentration of from 10 to 20 TU, a range that most 

likely is made up of water recharged from the present 

to about 15 years ago and within the timeframe of 

residential development in the area of the wells. The 

apparent age from 3H/3He data for water from 24 

monitoring wells ranged from 1 year or less to 38 years 

old, relative to 1999 (table 5). Water from 20 of the 

wells became isolated from the atmosphere 0 to 15 

years before 1999 on the basis of 3H/3He dating.

Wells 26S and 41 are the shallowest wells in the 

study (31 and 23 ft, respectively) and contain water 1 

year or less old. Water temperature, water level, and 

stable isotope ratio changes confirm recent recharge to 

well 26S from Little Cottonwood Creek. Rapid 

recharge to the ground-water system is possible in 

other areas where recharge sources and permeable 

aquifer material occur, such as along creeks and canals 

in the primary and secondary recharge areas. Some of 

the deepest monitoring wells also contained water that 

recharged the water table within the last 2 years. Depth 

to water in wells 30, 31, and 39 is about 58, 143, and 94 

ft below land surface, respectively. The time spent in 

the unsaturated zone is not included in the 3H/3He age 

determination and may be considerable depending on 

the amount of recharge, the permeability, and the 

thickness of unsaturated deposits overlying the water 

table.

Tritium concentrations in water from the 

monitoring wells determined from 3H/3He ages and 

corrected for radioactive decay over time generally are 

similar to those measured in or extrapolated for 

precipitation (fig. 21). The correlation between tritium 

in recently recharged ground water and precipitation 

indicates that most or all of the water in the shallow 

system is from the land surface with little or no mixing 

with older water.

The lowest tritium concentration (1.67 TU) was 

measured in water from well 4 (table 5) and represents 

a component of water recharged before the tritium peak 

in 1963 caused by atmospheric testing. The 3H/3He 

apparent age determined for this water is about 1962. 

The tritium concentration in 1962, based on a 

concentration of 1.67 TU in water from well 4 in 1999 

and a half-life of 12.43 years, is about 13 TU (fig. 21). 

Tritium concentration measured in precipitation in Salt 

Lake City is available for 1963-84 and has been 

extrapolated from 1961 to 2000 on the basis of 

correlation with data from Vienna, Austria (Robert 

Michel, U.S. Geological Survey, written commun., 

2002) (fig. 21). Extrapolated monthly tritium 

concentrations in 1961-62 precipitation ranged from 

about 35 to 1,600 TU, much higher than 13 TU 

determined from the 3H/3He apparent age. These 

values would have decayed to about 4 to 200 TU in 

1999 rather than the 1.67 TU measured in water from 

well 4. Because higher tritium concentrations were not 

measured in water from well 4, older water with no 

tritium probably is mixing with younger, tritiated 

water, resulting in a younger apparent age.

The highest tritium concentration (54.76 TU) 

was measured in water from well 29 and represents a 

large component of water recharged in the 1960s when 

the peak in tritium concentrations in the atmosphere 

occurred. This water, on the basis of the 3H/3He 

method, was isolated from the atmosphere and 
40 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

 recharged the shallow ground-water system in 1967. 

Tritium measured in Salt Lake City precipitation in 

1967 would have decayed to about the concentration 

measured in 1999 on the basis of a half-life of 12.43 

years. Many of the samples from the monitoring wells 

on the west side of the valley plot slightly above the 

line representing tritium concentration in precipitation 

(fig. 21). This may be the result of mixing with water 

recharged during the preceding 20 to 30 years that has 

been impeded by clay layers.

Chlorofluorocarbons 

Chlorofluorocarbons (CFCs) are synthetic 

organic compounds that were developed in the early 

1930s as coolants in air conditioning and refrigeration 

(Plummer and Friedman, 1999). Other uses included 

blowing agents in foams, insulation, and packing 

materials, propellants in aerosol cans, and as solvents 

in the electronics industry. Chlorofluorocarbons are 

used as environmental tracers and dating tools for 

water that has been in contact with the atmosphere 

since the 1940s. Ground-water samples from the 

monitoring wells were analyzed for CFC-11 

(trichlorofluoromethane or CFCl3), CFC-12 

(dichlorodifluoromethane or CF2Cl2), and CFC-113 

(trichlorotrifluoroethane or C2F3Cl3) (table 5). 

Ground-water age is estimated by relating the 

measured concentration of the environmental tracer in 

water to the historical atmospheric concentration and to 

a calculated concentration expected in water in 

equilibrium with air.

Apparent ground-water ages determined in this 

study from CFC concentrations generally are similar to 

ages determined by using the 3H/3He method (table 5). 

Water sampled from well 29 had CFC-11 and CFC-113 

concentrations that corresponded to a time of recharge 

before 1955. The water from this well is anoxic, which 

can degrade these compounds and result in apparent 

older CFC ages. CFC-12 does not decay under sulfatereducing conditions and provided an age date of 1973 

that is closer to the 3H/3He date of 1967 for this water 

sample. Most of the water samples had CFC 

concentrations that were greater than what was possible 

for equilibrium with the atmosphere. Ground water 

from these wells was contaminated with CFCs from 

1

10

100

1,000

10,000

1960 1965 1970 1975 1980 1985 1990 1995 2000

Precipitation—Extrapolated based on correlation with

data from Vienna, Austria (Robert Michel, U.S.

Geological Survey, written commun., 2002)

Precipitation—Measured in Salt Lake City (International

Atomic Energy Agency, 2001)

Water from monitoring well—Determined from

tritium/helium-3 apparent age and tritium half-life;

number next to symbol is the well identifier shown in

figure 3

37

4 6

18

32 14

10 8

24 25

3

17 5 9

2

33

22

29

31

27

39

30 41

26S

33

TRITIUM CONCENTRATION, IN TRITIUM UNITS

Figure 21. Tritium concentration in precipitation and in water sampled from monitoring wells in areas of recent residential development, Salt Lake 

Valley, Utah.
Effects of Shallow Ground-Water Quality on Deeper Ground-Water Quality 41

anthropogenically affected sources with concentrations 

in excess of that of atmospheric sources. CFC-11 was 

detected in water sampled from two monitoring wells, 

and CFC-113 was detected in water from one well in 

the parts per billion range as part of the VOC analysis. 

Although a recharge date cannot be determined from 

these contaminated samples, the presence of CFCs 

indicates that the water has been in contact with human 

activities at the land surface.

EFFECTS OF SHALLOW GROUND-WATER 

QUALITY ON DEEPER GROUND-WATER 

QUALITY 

Water from the deeper aquifer underlying the 

shallow ground-water system is used for public supply 

in Salt Lake Valley. The potential exists for movement 

of anthropogenic compounds from shallow ground 

water to the deeper aquifer in recently developed 

residential areas where a downward hydraulic gradient 

exists between the aquifers. The monitoring wells 

installed for this study were located in areas assumed to 

have a downward hydraulic gradient from the shallow 

to the deeper aquifer on the basis of information from 

well-drillers’ logs (Anderson and others, 1994). 

Contamination of the principal aquifer from activities 

at land surface has been documented in the valley 

(Waddell and others, 1987). 

Water used for public supply from the principal 

aquifer in Salt Lake Valley was sampled as part of the 

NAWQA program. Many of the sampled wells in the 

primary and secondary recharge areas had a component 

of water that was recharged during the last 50 years 

(contained detectable tritium) and had detectable 

concentrations of chloroform. Even in some areas with 

an upward gradient between the deeper and shallow 

aquifers, anthropogenic compounds were detected, 

indicating a connection with land surface. Changes in 

water-level gradients caused by pumping may result in 

water movement from the shallow to the deeper 

aquifer.

Water levels in monitoring wells on the east side 

of the valley ranged from about 5 to 94 ft below land 

surface. Shallow ground water is perched about 300 ft 

above the deeper aquifer by confining layers in the area 

of wells 29, 32, and 34. The shallow and deeper 

ground-water systems in this area are separated by 

sequences of fine-grained deposits that perch the 

shallow ground water and confine the deeper aquifer. 

Different sources of recharge also contribute to the 

large downward gradient between the two systems: 

subsurface inflow from the Wasatch Range to the 

deeper aquifer, and local precipitation and unconsumed 

irrigation water to the shallow system. Anthropogenic 

compounds were not detected in water sampled from 

monitoring well 32 or a nearby public-supply well 

completed in the deeper confined aquifer. The deeper 

confined aquifer in this part of the valley is probably 

more isolated from activities occurring at the land 

surface because of confining layers and different 

recharge sources.

Water levels in monitoring wells in the 

northwestern part of the valley ranged from about 12 to 

80 ft below land surface. No large hydraulic gradient 

exists between the shallow and deeper aquifers in this 

area despite the presence of confining layers. 

Anthropogenic compounds are more prevalent in the 

shallow ground water. Pumping from the deeper 

aquifer may cause water to move downward from the 

shallow aquifer in some areas. Fewer wells pump water 

from the deeper aquifer in the secondary recharge area 

on the west side of Salt Lake Valley than on the east 

side generally because of poorer yield and chemical 

quality.

Anthropogenic compounds were detected in 

water from both monitoring well 8 and a nearby publicsupply well completed in the deeper confined aquifer 

on the west side of the valley. Atrazine concentrations 

were about an order of magnitude higher in water from 

the deeper well (0.195 μg/L) than in water from the 

shallower monitoring well (0.023 μg/L). Water from 

the deeper well and well 8 had chloroform 

concentrations of 0.66 μg/L and 1.16 μg/L, 

respectively, and PCE concentrations of 1.0 μg/L and 

1.9 μg/L, respectively. The water levels in both wells 

were similar under static conditions (about 60 ft below 

land surface) but dropped almost 100 ft in the deeper 

well when pumping. A thick layer of clay noted on the 

drillers’ log of the deeper well (124-182 ft below land 

surface) occurs between the water table and the top of 

the screened interval. The specific-conductance value 

of water was about 1,000 μS/cm in the shallow well 

under both static and pumping conditions and in water 

from the deeper well while pumping. The specificconductance value of water in the deeper well at about 

90 ft below land surface under static conditions was 

350 μS/cm and is probably representative of the water 

in the aquifer at the screened interval (172-253 ft below 
42 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

land surface). The occurrence of VOCs in water 

pumped from the deeper well may be caused by 

shallow water that has moved downward despite the 

presence of the intervening clay layer. The higher 

concentration of atrazine in the deeper well may result 

from water recharged at land surface where the 

herbicide was used in the primary recharge area.

The water level in monitoring well 31 in the 

southwestern part of the valley is about 140 ft below 

land surface, similar to that of domestic wells in the 

area. The anthropogenic compounds chloroform, PCE, 

TCA, atrazine, and simazine were present in water 

from this well despite the relatively deep water table. 

The boundary between the shallow and deeper aquifers 

in this area is not clearly defined because of thin and 

(or) discontinuous confining layers. Water from local 

precipitation and seepage from unconsumed irrigation 

and canals, primary sources of recharge to the shallow 

aquifer, also may be major sources of recharge to the 

deeper aquifer in the area. Where this is the case, 

activities occurring at land surface have the potential to 

affect the water quality of the deeper confined aquifer 

in the southwestern part of the valley. Contamination of 

the principal aquifer from mine-waste water that was 

impounded at land surface occurred downgradient from 

the Bingham Canyon mining area (Waddell and others, 

1987, p. 19), but upgradient from major confining 

layers. 

RELATION BETWEEN GROUND-WATER 

QUALITY AND LAND USE

The relation between the concentration of 

selected constituents and compounds in ground-water 

samples collected from the monitoring wells and the 

type of land use within 1,640 ft of each well was 

examined by using statistical correlation. The 

Spearman rank correlation test was used to measure the 

strength of association between two variables (Helsel 

and Hirsch, 1992, p. 209-218). The correlation 

coefficient (rho) varies from 1 to -1 and describes the 

strength of the correlation. Values closer to 1 indicate a 

positive correlation, values closer to -1 indicate an 

inverse correlation, and values closer to 0 indicate no 

correlation. The p-value (probability of no correlation) 

was used to evaluate the significance of the correlation; 

p-values less than 0.10 are considered statistically 

significant.

No correlation was determined between the 

percentage of residential land use surrounding the 

monitoring wells and the concentration of dissolved 

solids, arsenic, atrazine and its degradation products, 

prometon, chloroform, or nitrate in water sampled from 

the wells. The total percentage of land classified as 

commercial, vacant, and roads weakly correlated with 

the concentration of atrazine and its degradation 

products in water sampled from the wells (p = 0.06, rho 

= 0.35). Atrazine applied to these land-use types may 

be a source of atrazine detected in the shallow ground 

water. Not enough agricultural land was delineated 

within 1,640 ft of the monitoring wells to determine if 

it is correlated to atrazine concentration in ground 

water. The source of atrazine and its degradation 

products also may be from areas more than 1,640 ft 

upgradient from the wells. In addition, chloroform 

concentration in the water samples did not correlate to 

percentages of these land-use types.

Dissolved-solids concentration strongly 

correlated with 2H (p = 0.0001, rho = 0.76), confirming 

that isotopically heavier irrigation water contains more 

dissolved solids than does isotopically lighter water 

recharged from mountain-front streams or local 

precipitation. Chloroform concentration did not 

correlate with dissolved-solids or nitrate concentration 

in water from the monitoring wells, probably because 

of mixing of recharge sources and different sources of 

nitrate. The relation between chloroform and the 

herbicides atrazine and prometon, although not 

statistically significant, varied differently. The three 

highest chloroform concentrations corresponded to 

three of the four highest prometon concentrations, 

likely because of the use of these compounds in 

residential areas. Relatively low concentrations of 

chloroform corresponded to the four highest 

concentrations of atrazine and its degradation products, 

probably because of atrazine use on agricultural or 

nonirrigated industrial and vacant land.

SUMMARY

Residential and commercial development of 

about 80 mi2 that primarily replaced undeveloped and 

agricultural areas occurred in Salt Lake Valley, Utah, 

from 1963 to 1994. This study evaluated the occurrence 

and distribution of natural and anthropogenic 

constituents in shallow ground water underlying 
Summary 43

recently developed (post 1963) residential and 

commercial areas. Monitoring wells from 23 to 153 ft 

deep were installed at 30 sites. Ground-water quality 

for the monitoring wells was evaluated by using 

analyses of field parameters, major ions, trace 

elements, radon, nutrients, dissolved organic carbon, 

pesticides, and volatile organic compounds. 

Dissolved-solids concentration ranged from 134 

to 2,910 mg/L in water from the 30 monitoring wells. 

Dissolved arsenic concentration in water from 12 wells 

exceeded the drinking water maximum contaminant 

level of 10 μg/L. Water from monitoring wells in the 

northwestern part of the valley generally had higher 

arsenic concentrations than did water from other areas. 

Nitrate concentration in water sampled from 26 of the 

30 monitoring wells (86.7 percent) was higher than a 

background level of 2 mg/L, indicating a possible 

human influence. Nitrate concentrations ranged from 

less than 0.05 to 13.3 mg/L. 

Fifteen of the 104 pesticides and pesticide 

degradation products analyzed for were detected in 1 or 

more water samples from the monitoring wells. No 

pesticides were detected at concentrations that 

exceeded U.S. Environmental Protection Agency 

drinking-water standards or guidelines. for 2002 Total 

concentration of pesticides and pesticide degradation 

products in water ranged from an estimated 0.002 μg/L 

(diazinon) to 2.56 μg/L (a mixture of atrazine, atrazine 

degradation products, and simazine). The high 

detection frequency of atrazine, a restricted-use 

pesticide, in residential areas on the west side of Salt 

Lake Valley may be the result of application in 

agricultural or industrial areas that have been converted 

to residential uses or application in areas upgradient 

from the residential areas that was then transported by 

ground water.

Fifteen of the 86 volatile organic compounds 

analyzed for were detected in 1 or more water samples 

from the monitoring wells. The most frequently 

detected volatile organic compounds were chloroform 

(90 percent), bromodichloromethane (56.7 percent), 

tetrachloroethylene (53.3 percent), and 1,1,1-

trichloroethane (50 percent). The widespread 

occurrence of chloroform and bromodichloromethane 

in shallow ground water is likely a result of chlorinated 

public-supply water used to irrigate lawns and gardens 

in residential areas of Salt Lake Valley. 

Tetrachloroethylene (PCE), primarily used as a dry 

cleaning agent and solvent, was detected in water from 

16 wells. Resampling of water from a well on the east 

side of the valley showed an increase in PCE 

concentration from 0.8 μg/L in 1999, to 2.5 μg/L in 

2000, and to 10.0 μg/L in 2001. This upward trend is an 

indication of ground water containing PCE moving 

past the well from an upgradient source. 

Stable isotopes indicate that ground water from 

the monitoring wells is a mixture of varying amounts of 

local precipitation and evaporated water. Because of 

evaporation, canal water diverted from the Jordan River 

and used for irrigation is isotopically heavier relative to 

precipitation occurring locally or on the adjacent 

mountains. Several wells on the east side of the valley 

are upgradient from canals that divert water from the 

Jordan River but contain a component of evaporated 

water. Chloroform was detected in water from these 

wells; thus, the water is likely a mixture of infiltration 

from local precipitation and seepage of water used for 

public supply. Recharge of sprinkler-irrigation water to 

the shallow ground-water system was observed 

isotopically in a 38.5-ft-deep monitoring well. Stable 

isotope ratios were heaviest in the summer when water 

was applied to the area upgradient from the monitoring 

well and became lighter in the winter and spring when 

no irrigation occurred.

Water from most of the wells had a tritium 

concentration of from 10 to 20 tritium units, a range 

that indicates ground water recharged from the present 

to about 15 years ago and within the timeframe of 

residential development in the area of the wells. The 

match between tritium in shallow ground water and 

precipitation indicates that most or all of the water in 

the shallow system is recent recharge from the land 

surface with little or no mixing with older ground 

water. Water from most of the monitoring wells was 

contaminated with chlorofluorocarbons, which also 

indicates that the water has been in contact with human 

activities at the land surface.

Subsurface inflow from the Wasatch Range is the 

main source of recharge to the deeper aquifer on the 

east side of the valley, and local precipitation and 

irrigation water are the main sources of recharge to the 

shallow system. As a result, the deeper aquifer in this 

part of the valley is more isolated than the shallow 

ground water from activities occurring at the land 

surface. No large hydraulic gradient exists between the 

shallow and deeper aquifers in the northwestern part of 

the valley and anthropogenic compounds are more 

prevalent in the shallow ground water. Pumping from 

the deeper confined aquifer, however, may cause water 

and anthropogenic compounds to move downward 
44 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

from the shallow aquifer. The anthropogenic 

compounds chloroform, tetrachloroethylene, 1,1,1-

trichloroethane, atrazine, and simazine were present in 

water from a monitoring well in the southwestern part 

of the valley despite the relatively deep water table. 

Water from local precipitation and seepage from 

irrigation and canals, primary sources of recharge to 

the shallow aquifer, also may be major sources of 

recharge to the deeper aquifer in this area because of 

thin or discontinuous confining layers. Where this is 

the case, activities occurring at land surface have the 

potential to affect the water quality of the deeper 

aquifer. 

No correlation was determined between the 

percentage of residential land use surrounding the 

monitoring wells and the concentration of dissolved 

solids, arsenic, atrazine and its degradation products, 

prometon, chloroform, or nitrate in water sampled from 

the wells. Chloroform concentration did not correlate 

with dissolved-solids or nitrate concentration in water 

from the monitoring wells; this may be a result of 

mixing of different sources of recharge and nitrate. 

Relatively low concentrations of chloroform 

corresponded to the four highest concentrations of 

atrazine and its degradation products; this may be a 

result of atrazine use on agricultural or nonirrigated 

industrial and vacant land.

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book of ASTM standards, section 11, Water and environmental technology: American Society for Testing 

and Materials, v. 11.02, D5072-92, p. 674-676.

Anderson, P.B., Susong, D.D., Wold, S.R., Heilweil, V.M., 

and Baskin, R.L., 1994, Hydrogeology of recharge 

areas and water quality of the principal aquifers along 

the Wasatch Front and adjacent areas, Utah: U.S. Geological Survey Water-Resources Investigations Report 

93-4221, 74 p.

Baehr, A.L., Stackelberg, P.E., and Baker, R.J., 1999, Evaluation of the atmosphere as a source of volatile organic 

compounds in shallow groundwater: Water Resources 

Research, v. 35, no. 1, p. 127-136.

Barbash, J.E., Thelin, G.P., Kolpin, D.W., and Gilliom, R.J., 

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Bayer, R., Schlosser, P., Bönisch, G., Rupp, H., Zaucker, F., 

and Zimmek, G., 1989, Performance and blank components of a mass spectrometric system for routine measurement of helium isotopes and tritium by the 3He 

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Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Klasse: Heidelberg, Springer Verlag, 

v. 5, p. 241-279.

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Appendix 47

APPENDIX

Table 6. Field parameters for water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3; well identification number is the site number used in the U.S. Geological Survey National Water 

Information System; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; NTU, nephelometric turbidity units; μg/L, 

micrograms per liter; <, less than; —, no data]

Well 

identifier

Well identification 

number

Sample 

date

Depth of 

well

(feet)

Water 

level

below 

land 

surface

(feet)

Temperature

(degrees 

Celsius)

Specific 

conductance

(μS/cm)

pH

(standard 

units)

Alkalinity, 

dissolved

(mg/L as 

CaCO3)

Oxygen, 

dissolved

(mg/L)

Turbidity

(NTU)

Chlorine

(μg/L)

Sulfide

(μg/L)

1 404104111582101 09/22/1999 48.5 30.91 15.5 1,340 7.3 375 4.9 0.6 <30 40

2 404044111572701 09/20/1999 38.5 18.66 16.0 2,740 6.9 433 4.4 .2 40 10

3 404022111580801 10/19/1999 114 74.67 19.0 1,520 7.3 294 6.3 .2 <30 10

4 404012111572101 09/20/1999 38.5 13.35 17.0 2,030 7.5 250 2.5 .6 <30 <10

5 404007111585801 09/27/1999 43.5 24.80 16.0 1,370 7.4 256 6.6 .1 <30 <10

6 403945111565401 10/07/1999 38.5 20.73 16.5 2,850 6.9 659 — 1.6 <30 <10

7 403943111575701 09/28/1999 43.5 21.38 16.5 1,790 7.3 313 5.8 .2 <30 240

8 403918111584201 10/18/1999 67.5 62.47 16.5 760 7.5 191 7.0 4.0 <30 <10

9 403914111560101 09/28/1999 38.5 7.96 15.0 2,190 7.2 374 1.8 .7 <30 <10

10 403915111565501 10/13/1999 83.5 72.48 18.5 3,000 7.3 274 5.2 .1 <30 <10

11 403914111580201 10/06/1999 83.5 67.12 18.0 2,150 7.1 369 4.7 .2 <30 10

14 403828111590401 09/30/1999 48.5 23.31 16.5 1,440 7.5 324 3.3 4.4 <30 10

17 403730111563201 09/23/1999 38.5 14.29 15.5 3,440 7.1 462 .7 .2 <30 10

18 403736111521401 09/13/1999 106 77.55 16.0 1,030 7.2 327 6.7 2.4 50 <10

20 403729111581701 10/05/1999 92.5 80.99 16.5 3,700 7.3 404 6.7 .1 <30 10

22 403713111501901 09/29/1999 36 20.29 14.0 650 7.5 191 2.0 .8 <30 <10

24 403659111580501 10/20/1999 124 76.38 15.0 3,050 7.0 453 4.6 .4 <30 —

25 403652111570201 10/12/1999 68.5 44.97 17.5 2,160 7.0 361 5.4 .6 <30 <10

26D 403627111495701 08/10/1999 77.5 22.96 10.5 350 7.8 85 5.3 2.3 — 10

26S 403627111495702 09/15/1999 31.5 20.50 16.0 235 7.0 68 3.7 .4 40 <10

27 403628111514301 09/07/1999 73.5 58.42 15.5 1,140 6.8 336 6.4 .4 100 <10

29 403638111505101 09/21/1999 34 8.81 13.5 485 7.5 192 .7 .4 <30 100

30 403609111573901 10/12/1999 68.5 51.12 17.0 1,660 7.1 350 6.9 .2 <30 <10

31 403544111584801 10/21/1999 154 135.17 14.5 1,370 7.6 304 8.7 1.5 <30 —

32 403524111512901 09/14/1999 88.5 75.87 14.0 710 7.3 239 8.0 12 <30 <10

33 403609111573901 10/14/1999 95.5 69.65 17.0 2,190 7.3 362 6.8 .1 <30 <10

34 403420111530101 090/9/1999 77.5 56.38 — 1,040 7.2 266 5.3 1.7 50 10

37 403316111510601 09/08/1999 73 45.01 15.0 600 7.5 176 5.8 5.6 80 <10

39 403244111504701 10/04/1999 106 92.80 18.5 860 7.5 298 6.2 .4 35 10

41 403129111510601 09/16/1999 23 5.27 15.5 730 6.9 228 3.4 .8 60 <10
48 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 7. Concentration of dissolved major ions in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; mg/L, milligrams per liter; μg/L, micrograms per liter; oC, degrees Celsius; number 

below the parameter name is the U.S. Geological Survey National Water Information System parameter code; <, less than; E, estimated value; M, presence of 

constituent verified but not quantified]

Well 

identifier

Bicarbonate

(mg/L as 

HCO3)

(00453)

Bromide

(mg/L as Br)

(71870)

Calcium

(mg/L as Ca)

(00915)

Chloride

(mg/L as Cl)

(00940)

Fluoride

(mg/L as F)

(00950)

Iron

(μg/L as Fe)

(01046)

Magnesium

(mg/L as Mg)

(00925)

1 463 0.21 60.4 105 0.6 20 47.0

2 522 .40 164 456 .7 <10 32.4

3 360 .25 89.1 191 .6 <10 53.7

4 310 .10 101 428 .8 40 61.0

5 320 .22 62.7 185 .7 <10 42.7

6 804 .45 210 382 .5 <10 101

7 385 .24 85.8 270 .9 170 56.0

8 233 .11 93.5 126 .2 <10 27.2

9 458 .33 140 275 1.1 <10 67.1

10 334 .52 226 401 .6 <10 141

11 450 .37 104 351 .6 <10 95.5

14 400 .08 61.3 194 1.0 <10 29.6

17 564 .34 448 276 .9 M 92.3

18 401 1.40 105 131 .4 <10 25.7

20 493 .23 137 182 .5 <10 175

22 233 .05 77.9 48.6 .8 20 26.2

24 557 .32 192 322 .2 <30 99.9

25 449 .32 150 276 .2 <10 53.5

26D 103 .02 20.6 40.8 .4 <10 4.96

26S 82 <.01 25.6 13.2 .2 <10 4.88

27 410 .12 128 118 .6 M 37.0

29 238 .02 51.3 12.9 1.9 540 22.9

30 427 .22 98.3 168 .4 <10 52.0

31 371 .16 54.7 188 .4 M 34.9

32 292 .03 89.6 48.1 .6 M 25.7

33 442 .23 113 230 .2 <10 48.7

34 324 .10 99.8 101 .9 <10 30.0

37 215 .08 77.1 35.0 .1 M 21.2

39 363 .06 93.4 47.2 .5 <10 25.8

41 279 .05 65.4 64.9 .6 M 33.1
Appendix 49

Table 7. Concentration of dissolved major ions in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Well 

identifier

Manganese

(μg/L as Mn)

(01056)

Potassium

(mg/L as K)

(00935)

Silica

(mg/L as SiO2)

(00955)

Sodium

(mg/L as Na)

(00930)

Sulfate

(mg/L as SO4)

(00945)

Solids, residue

at 180oC

(mg/L)

(70300)

Solids, sum of 

constituents

(mg/L)

(70301)

1 148 18.4 39.4 157 139 804 829

2 <2.2 21.9 37.2 267 353 1,800 1,620

3 2.2 14.4 38.4 154 218 982 974

4 44.8 11.7 40.3 212 134 1,190 1,150

5 <2.2 9.69 42.8 162 143 818 838

6 38.4 33.8 40.2 263 361 1,850 1,810

7 49.5 19.3 37.3 189 209 1,080 1,080

8 2.9 4.74 37.2 75.8 110 636 619

9 8.0 31.4 28.5 213 394 1,410 1,390

10 <2.2 21.9 47.6 241 816 2,200 2,100

11 12.4 23.2 47.0 195 208 1,300 1,300

14 3.6 17.4 46.3 190 101 848 874

17 36.9 50.0 49.9 228 1,210 2,820 2,690

18 E1.5 6.06 16.6 82.9 49.0 618 635

20 40.5 57.8 51.6 473 1,480 2,910 2,830

22 25.5 4.64 15.4 14.8 64.4 381 386

24 12 14.4 39.8 338 749 2,180 2,030

25 2.9 14.2 36.9 246 378 1,440 1,410

26D E1.8 1.35 6.5 38.1 16.9 189 181

26S E1.4 1.56 6.6 12.6 24.3 134 131

27 E1.7 7.52 22.1 67.8 80.0 718 696

29 110 4.46 18.3 10.3 31.4 282 271

30 10.3 10.3 26.6 179 263 1,060 1,040

31 65.2 10.9 25.3 163 94.2 806 797

32 2.4 4.34 17.0 15.2 41.4 405 414

33 <2.2 7.72 41.8 322 505 1,510 1,500

34 <2.2 7.21 30.3 65.8 85.4 626 614

37 10.4 4.63 15.7 16.7 42.3 383 378

39 18.7 5.76 20.8 53.7 64.4 521 534

41 <2.2 5.43 18.2 40.0 40.9 445 426
50 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 8. Concentration of trace elements in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; water samples for Radon-222 analysis were not filtered; μg/L, micrograms per liter; 

pCi/L, picocuries per liter; number below the parameter name is the U.S. Geological Survey National Water Information System parameter code; <, less than; 

E, estimated value]

Well 

identifier

Dissolved 

aluminum

(μg/L as Al)

(01106)

Dissolved

antimony

(μg/L as Sb)

(01095)

Dissolved

arsenic

(μg/L as As)

(01000)

Dissolved

barium

(μg/L as Ba)

(01005)

Dissolved

beryllium

(μg/L as Be)

(01010)

Dissolved

cadmium

(μg/L as Cd)

(01025)

Dissolved

chromium

(μg/L as Cr)

(01030)

Dissolved

cobalt

(μg/L as Co)

(01035)

Dissolved

copper

(μg/L as Cu)

(01040)

1 2 <1.00 9.9 62.7 <1.00 <1.00 0.9 <1.00 1.1

2 1 <1.00 10.2 36.6 <1.00 <1.00 2.9 <1.00 3.0

3 3 <1.00 12.2 28.3 <1.00 <1.00 E.7 <1.00 1.3

4 <1 <1.00 19.6 74.2 <1.00 <1.00 1.9 <1.00 1.1

5 1 <1.00 13.7 33.9 <1.00 <1.00 2.7 <1.00 1.3

6 2 <1.00 14.5 39.6 <1.00 <1.00 E.5 <1.00 3.9

7 1 <1.00 11.7 36.3 <1.00 <1.00 1.0 <1.00 1.2

8 3 <1.00 13.9 53.1 <1.00 <1.00 1.7 <1.00 <1.0

9 1 <1.00 2.1 24.7 <1.00 <1.00 3.5 <1.00 2.3

10 5 <1.00 13.4 19.5 <1.00 <1.00 2.6 <1.00 4.9

11 <1 <1.00 11.2 35.1 <1.00 <1.00 E.7 <1.00 1.9

14 <1 <1.00 15.4 98.8 <1.00 <1.00 .8 <1.00 1.7

17 1 <1.00 7.0 47.7 <1.00 <1.00 <1.0 1.05 10

18 1 <1.00 <1.0 202 <1.00 <1.00 1.2 <1.00 2.3

20 1 <1.00 17.7 11.8 <1.00 <1.00 .9 1.09 6.7

22 2 <1.00 <2.0 142 <1.00 <1.00 <.8 <1.00 <1.0

24 3 <1.00 7.3 20.3 <1.00 <1.00 3.1 <1.00 2.7

25 <1 <1.00 12.5 17.5 <1.00 <1.00 2.9 <1.00 6.1

26D 10 1.69 <1.0 51.7 <1.00 <1.00 <1.0 <1.00 <1.0

26S 2 1.30 2.0 71.4 <1.00 <1.00 <1.0 <1.00 1.0

27 1 <1.00 1.3 140 <1.00 <1.00 2.5 <1.00 2.3

29 2 <1.00 5.6 81.1 <1.00 <1.00 <.8 <1.00 <1.0

30 <1 <1.00 7.3 39.6 <1.00 <1.00 2.2 <1.00 3.5

31 3 <1.00 6.3 95.0 <1.00 <1.00 4.7 <1.00 1.5

32 2 <1.00 <1.0 209 <1.00 <1.00 1.4 <1.00 2.4

33 <1 <1.00 10.8 14.7 <1.00 <1.00 3.4 <1.00 3.5

34 2 <1.00 <1.0 112 <1.00 <1.00 <1.0 <1.00 2.1

37 3 <1.00 1.1 255 <1.00 <1.00 1.7 <1.00 1.3

39 2 <1.00 3.3 130 <1.00 <1.00 1.5 <1.00 2.3

41 1 <1.00 <1.0 150 <1.00 <1.00 <1.0 <1.00 1.6 12-Sigma precision estimate.
Appendix 51

Table 8. Concentration of trace elements in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Well 

identifier

Dissolved

lead

(μg/L as Pb)

(01049)

Dissolved

molybdenum

(μg/L as Mo)

(01060)

Dissolved

nickel

(μg/L as Ni)

(01065)

Total

radon-222

(pCi/L)

(82303)

Radon-222

2-sigma1

(pCi/L)

(76002)

Dissolved

selenium

(μg/L as Se)

(01145)

Dissolved

silver

(μg/L as Ag)

(01075)

Dissolved

uranium

(μg/L as U)

(22703)

Dissolved

zinc

(μg/L as Zn)

(01090)

1 <1.00 8.1 2.56 700 26 1.2 <1.0 8.11 1

2 <1.00 99.1 2.17 589 23 2.1 <2.0 16.2 4

3 <1.00 5.0 1.83 243 18 2.6 <1.0 5.29 2

4 <1.00 5.5 3.91 514 23 <1.0 <1.0 4.70 3

5 <1.00 4.3 1.37 503 27 2.5 <1.0 4.44 2

6 <1.00 19.4 4.74 404 22 <2.4 <1.0 16.0 3

7 <1.00 8.3 1.95 400 21 E1.5 <1.0 7.10 <1

8 <1.00 <1.0 2.96 485 23 <2.4 <1.0 2.60 2

9 <1.00 55.7 2.61 506 24 4.0 <1.0 22.3 2

10 <1.00 11.1 5.15 559 24 13.0 <1.0 13.5 6

11 <1.00 2.7 1.97 297 20 <2.4 <1.0 10.9 2

14 <1.00 6.9 2.50 524 24 2.6 <1.0 11.5 3

17 <1.00 45.4 7.88 825 27 1.7 <1.0 26.6 6

18 <1.00 3.9 2.34 522 23 <1.0 <1.0 8.01 3

20 <1.00 2.5 3.68 678 26 4.2 <1.0 8.62 8

22 <1.00 27.8 1.30 1,250 33 3.0 <1.0 38.9 3

24 <1.00 <1.0 3.69 535 24 E3.0 <1.0 13.9 4

25 <1.00 4.3 4.19 810 27 3.0 <1.0 12.4 4

26D <1.00 8.1 5.42 658 25 <1.0 <1.0 4.74 <1

26S <1.00 4.3 <1.00 641 24 <1.0 <1.0 1.50 1

27 <1.00 3.0 5.81 920 28 <1.0 <1.0 5.16 1

29 <1.00 95.2 <1.00 719 26 <1.0 <1.0 <1.00 <1

30 <1.00 4.1 3.01 352 20 3.6 <1.0 10.4 4

31 <1.00 10.2 5.82 679 27 <2.4 <1.0 2.68 6

32 <1.00 2.0 4.03 1,170 32 <1.0 <1.0 22.8 2

33 <1.00 1.6 2.97 635 25 2.6 <1.0 8.89 3

34 <1.00 7.5 3.39 491 31 <1.0 <1.0 36.2 5

37 <1.00 1.5 3.29 2,190 42 <1.0 <1.0 8.04 2

39 <1.00 3.4 3.24 462 22 <2.4 <1.0 21.2 2

41 <1.00 2.8 1.43 1,130 31 <1.0 <1.0 92.7 2
52 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 9. Concentration of nutrient constituents and organic carbon in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999 

[Well identifier corresponds to site shown in figure 3 and listed in table 6; mg/L, milligrams per liter; number below the parameter name is the U.S. Geological 

Survey National Water Information System parameter code; <, less than; E, estimated value]

Well

identifier

Dissolved

ammonia

(mg/L as N)

(00608)

Dissolved

ammonia plus 

organic nitrogen

(mg/L as N)

(00623)

Dissolved

organic

carbon

(mg/L as C)

(00681)

Dissolved

nitrite

(mg/L as N)

(00613)

Dissolved

nitrite plus

nitrate

(mg/L as N)

(00631)

Dissolved

phosphorus

(mg/L as P)

(00666)

Dissolved

orthophosphorus

(mg/L as P)

(00671)

1 <0.020 0.15 4.6 0.019 7.66 .036 .034

2 <.020 .32 2.0 <.010 7.35 .074 .063

3 <.020 .14 E1.1 <.010 8.55 .028 .028

4 .030 .14 3.2 .012 2.37 .031 .025

5 <.020 E.08 .86 <.010 7.05 .024 .032

6 <.020 .34 E4.5 <.010 5.46 .089 .084

7 <.020 .15 1.3 <.010 4.72 .017 .019

8 <.020 E.08 E.79 <.010 6.67 .033 .031

9 <.020 <.10 1.3 <.010 3.55 .029 .033

10 .029 .15 1.1 <.010 9.78 .033 .028

11 <.020 .17 1.8 <.010 12.0 .029 .028

14 <.020 .18 1.9 .100 8.15 .067 .064

17 <.020 .33 3.2 .107 12.7 .179 .162

18 <.020 .12 1.5 <.010 4.35 .013 .019

20 .021 .15 2.1 <.010 6.85 .051 .056

22 <.020 E.06 .71 <.010 4.14 .006 <.010

24 <.020 .24 E1.5 <.010 1.38 .065 .060

25 .031 .13 1.4 <.010 7.20 .058 .050

26D <.020 <.10 1.3 <.010 .246 <.004 <.010

26S <.020 <.10 .60 <.010 .200 .154 .133

27 <.020 .14 1.9 <.010 7.50 .013 .016

29 .043 E.07 .80 <.010 <.050 .022 .023

30 .023 .13 1.5 <.010 6.81 .037 .028

31 <.020 .12 .72 <.010 9.49 .027 .024

32 <.020 .22 2.0 <.010 6.39 .006 <.010

33 .022 .14 1.5 <.010 3.94 .058 .049

34 <.020 .12 1.9 <.010 7.71 .011 .015

37 <.020 E.07 1.1 <.010 13.3 .191 .172

39 <.020 .22 2.0 .012 9.96 .029 .027

41 <.020 .13 1.5 <.010 4.45 .207 .189
Appendix 53

Compound Parameter

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting level 

(μg/L)

Gas Chromatography/Mass Spectrometry analytical method

Acetochlor 49260 34256-82-1 0.002

Alachlor 46342 15972-60-8 .002

alpha-HCH 34253 319-84-6 .002

Atrazine 39632 1912-24-9 .001

Azinphos-methyl 82686 86-50-0 .001

Benfluralin 82673 1861-40-1 .002

Butylate 04028 2008-41-5 .002

Carbaryl 82680 63-25-2 .003

Carbofuran 82674 1563-66-2 .003

Chlorpyrifos 38933 2921-88-2 .004

cis-Permethrin 82687 54774-45-7 .005

Cyanazine 04041 21725-46-2 .004

Dacthal 82682 1861-32-1 .002

Deethylatrazine 04040 6190-65-4 .002

Diazinon 39572 333-41-5 .002

Dieldrin 39381 60-57-1 .001

2,6-Diethylaniline 82660 579-66-8 .003

Disulfoton 82677 298-04-4 .017

EPTC 82668 759-94-4 .002

Ethalfluralin 82663 55283-68-6 .004

Ethoprophos 82672 13194-48-4 .003

Fonofos 04095 944-22-9 .003

Lindane 39341 58-89-9 .004

Linuron 82666 330-55-2 .002

Malathion 39532 121-75-5 .005

Metolachlor 39415 51218-45-2 .002

Metribuzin 82630 21087-64-9 .004

Molinate 82671 2212-67-1 .004

Napropamide 82684 15299-99-7 .003

p,p'-DDE 34653 72-55-9 .006

Parathion 39542 56-38-2 .004

Parathion-methyl 82667 298-00-0 .006

Pebulate 82669 1114-71-2 .004

Pendimethalin 82683 40487-42-1 .004

Phorate 82664 298-02-2 .002

Prometon 04037 1610-18-0 .018

Propachlor 04024 1918-16-7 .007

Propanil 82679 709-98-8 .004

Propargite 82685 2312-35-8 .013

Propyzamide 82676 23950-58-5 .003

Simazine 04035 122-34-9 .005

Tebuthiuron 82670 34014-18-1 .010

Terbacil 82665 5902-51-2 .007

Terbufos 82675 13071-79-9 .013

Thiobencarb 82681 28249-77-6 .002

Triallate 82678 2303-17-5 .001

Trifluralin 82661 1582-09-8 .002

High-Performance Liquid Chromatography analytical method1

2,4-D 39732 94-75-7 .08

2,4-D methyl ester 50470 1928-38-7 .086

2,4-DB 38746 94-82-6 .05

2-Hydroxyatrazine 50355 2163-68-0 .193

3(4-Chlorophenyl)-1-

methyl urea

61692 5352-88-5 .0915

3-Hydroxycarbofuran 49308 16655-82-6 .062

3-Ketocarbofuran 50295 16709-30-1 .072

Acifluorfen 49315 50594-66-6 .06

Aldicarb 49312 116-06-3 .08

Aldicarb sulfone 49313 1646-88-4 .16

Aldicarb sulfoxide 49314 1646-87-3 .03

Atrazine 39632 1912-24-9 .074

Bendiocarb 50299 22781-23-3 .061

Benomyl 50300 17804-35-2 .022

Bensulfuron-methyl 61693 83055-99-6 .0482

Bentazon 38711 25057-89-0 .02

Bromacil 04029 314-40-9 .08

Bromoxynil 49311 1689-84-5 .06

Caffeine 50305 58-08-2 .081

Carbaryl 49310 63-25-2 .06

Carbofuran 49309 1563-66-2 .06

Chloramben, methyl ester 61188 7286-84-2 .11

Chlorimuron-ethyl 50306 90982-32-4 .037

Chlorothalonil 49306 1897-45-6 .05

Clopyralid 49305 1702-17-6 .04

Cycloate 04031 1134-23-2 .05

Dacthal monoacid 49304 887-54-7 .07

Deethylatrazine 04040 6190-65-4 .087

Deethyldeisopropylatrazine 04039 3397-62-4 .06

Deisopropylatrazine 04038 1007-28-9 .07

Dicamba 38442 1918-00-9 .10

Dichlorprop 49302 120-36-5 .05

Dinoseb 49301 88-85-7 .04

Diphenamid 04033 957-51-7 .06

Diuron 49300 330-54-1 .08

Fenuron 49297 101-42-8 .07

Flumetsulam 61694 98967-40-9 .0866

Fluometuron 38811 2164-17-2 .06

Imazaquin 50356 81335-37-7 .103

Imazethapyr 50407 81335-77-5 .088

Imidacloprid 61695 138261-41-3 .106

Linuron 38478 330-55-2 .07

MCPA 38482 94-74-6 .06

MCPB 38487 94-81-5 .062

Metalaxyl 50359 57837-19-1 .057

Methiocarb 38501 2032-65-7 .08

Methomyl 49296 16752-77-5 .08

Methomyl Oxime 61696 — .0102

Compound Parameter

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting level 

(μg/L)

Table 10. Pesticides and degradation products analyzed for in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Parameter code is used in U.S. Geological Survey National Water Information System database; μg/L, micrograms per liter; —, no number]
54 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

High-Performance Liquid Chromatography analytical method1—

Continued

Metsulfuron methyl 61697 74223-64-6 .114

Neburon 49294 555-37-3 .07

Nicosulfuron 50364 111991-09-4 .065

Norflurazon 49293 27314-13-2 .08

Oryzalin 49292 19044-88-3 .07

Oxamyl 38866 23135-22-0 .02

Oxamyl Oxime 38866 — .064

Picloram 49291 2/1/1918 .07

Propham 49236 122-42-9 .07

Propiconazole 50471 60207-90-1 .064

Propoxur 38538 114-26-1 .06

Siduron 38548 1982-49-6 .093

Sulfometuron-methyl 50337 74222-97-2 .039

Tebuthiuron 82670 34014-18-1 .010

Terbacil 04032 5902-51-2 .10

Tribenuron-methyl 61159 101200-48-0 .07

Triclopyr 49235 55335-06-3 .10

1 The samples from this study were analyzed by the high-performance 

liquid chromatography/mass spectrometry method before its final 

approval by the U.S. Geological Survey Office of Water Quality in 

2001. Although the analytical method did not change following 

approval, data analyzed before method approval are considered 

provisional. Ninety percent of the ground-water samples analyzed 

with this method in this study exceeded the recommended 4-day 

holding time prior to sample extraction (Furlong and others, 2001). 

Degradation of pesticides during extended sample storage is likely, 

and concentrations and detection frequencies for the pesticides 

analyzed by this method may be biased low.

Compound Parameter

code

Chemical 

Abstracts 

Service 

registry 

number

Minimum 

reporting level 

(μg/L)

Table 10. Pesticides and degradation products analyzed for in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued
Appendix 55
56 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 11. Concentration of dissolved pesticides detected in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; number below the parameter name is the U.S. Geological Survey National Water 

Information System parameter code; concentration reported in micrograms per liter; E, estimated value; <, less than; M, presence of compound verified but 

not quantified]

Well

identifier

Atrazine

(39632)

Deethylatrazine

(04040)

Deethyldeisopropylatrazine1

(04039)

Deisopropylatrazine1

(04038)

2-Hydroxyatrazine1

(50355)

Bromacil1

(04029)

Caffeine1

(50305)

Cycloate1,2

(04031)

Diazinon

(39572)

1 0.196 E0.025 E0.01 <0.07 E0.044 <0.08 <0.081 <0.05 <0.002

2 .208 E.059 E.01 <.07 E.052 <.08 <.081 <.05 <.002

3 .049 E.011 E.01 <.07 <.193 <.08 <.081 <.05 <.002

4 .880 E.307 .06 E.03 E.203 <.08 <.081 <.05 <.002

5 .232 E.136 E.01 <.07 E.055 <.08 <.081 E.04 <.002

6 .062 E.048 E.01 <.07 <.193 <.08 <.081 <.05 <.002

7 .382 E.061 E.03 E.02 E.096 .19 <.081 E.03 <.002

8 .023 E.024 M <.07 <.193 <.08 <.081 <.05 <.002

9 .188 E.046 E.01 <.07 E.064 <.08 <.081 E.04 <.002

10 .033 E.008 <.06 <.07 <.193 <.08 <.081 <.05 <.002

11 1.58 E.320 E.12 E.01 E.511 <.08 <.081 <.05 <.002

14 <.001 E.004 <.06 <.07 <.193 <.08 <.081 E.03 <.002

17 .229 E.098 E.02 <.07 E.066 <.08 <.081 <.05 <.002

18 E.004 <.087 <.06 <.07 <.193 <.08 <.081 <.05 <.002

20 .005 E.021 M <.07 <.193 <.08 <.081 <.05 <.002

22 <.001 <.002 <.06 <.07 <.193 <.08 <.081 <.05 E.002

24 .115 E.030 E.01 <.07 <.193 <.08 <.081 <.05 <.002

25 .345 E.106 E.02 <.07 E.055 <.08 <.081 <.05 <.002

26D .009 <.002 <.06 <.07 <.193 <.08 <.081 <.05 <.002

26S <.001 <.002 <.06 <.07 <.193 <.08 E.011 <.05 <.002

27 .019 <.002 M <.07 <.193 <.08 <.081 <.05 <.002

29 <.001 <.002 <.06 <.07 <.193 <.08 E.029 <.05 <.002

30 .012 E.006 M <.07 <.193 <.08 <.081 <.05 <.002

31 1.03 E.093 E.04 E.02 E.185 <.08 <.081 <.05 <.002

32 <.001 <.002 <.06 <.07 <.193 <.08 <.081 <.05 <.002

33 .031 E.022 E.01 <.07 <.193 <.08 <.081 <.05 <.002

34 .018 E.012 M <.07 <.193 <.08 <.081 <.05 <.002

37 <.001 <.002 <.06 <.07 <.193 <.08 <.081 <.05 <.002

39 .029 E.016 <.06 <.07 <.193 <.08 <.081 <.05 <.002

41 <.074 <.087 <.06 <.07 <.193 <.08 <.081 <.05 <.002 1 Compound was analyzed by the high-performance liquid chromatography/mass spectrometry method before its final approval by the U.S. 

Geological Survey Office of Water Quality in 2001. Although the analytical method did not change following approval, data analyzed before method 

approval are considered provisional. 2 Presence of compound in sample(s) may be the result of contamination. Compound was not included in analysis of pesticide data.
Appendix 57

Table 11. Concentration of dissolved pesticides detected in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Well

identifier

Diuron1

(49300)

Imazaquin1,2

(50356)

Malathion

(39532)

P,P' DDE

(34653)

Picloram1

(49291)

Prometon

(04037)

Simazine

(04035)

Tebuthiuron

(82670)

1 <0.08 <0.103 <0.005 <0.006 <0.07 0.518 0.027 <0.010

2 <.08 <.103 <.010 <.006 <.07 .105 .008 .120

3 <.08 <.103 <.005 <.006 <.07 <.018 .019 <.010

4 <.08 <.103 <.010 <.006 .47 .043 <.005 <.010

5 <.08 E.006 <.005 <.006 <.07 <.018 .006 <.010

6 <.08 <.103 <.005 <.006 <.07 .021 E.004 .051

7 .32 <.103 <.005 <.006 <.07 E.016 .023 <.010

8 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

9 <.08 <.103 <.005 <.006 <.07 .026 .006 <.010

10 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

11 <.08 <.103 <.005 <.006 <.07 <.018 .013 <.010

14 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

17 <.08 <.103 <.005 <.006 <.07 .022 .010 <.010

18 <.08 <.103 <.005 <.006 <.07 .216 .013 E.028

20 <.08 <.103 .006 <.006 <.07 <.018 <.005 <.010

22 <.08 E.006 <.005 <.006 <.07 <.018 <.005 <.010

24 <.08 <.103 <.005 <.006 <.07 <.018 .009 <.010

25 <.08 <.103 <.005 <.006 <.07 E.015 .011 <.010

26D <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

26S <.08 <.103 <.005 <.006 <.07 E.005 <.005 <.010

27 <.08 <.103 <.005 <.006 <.07 .125 <.005 <.010

29 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

30 <.08 <.103 <.005 <.006 <.07 .030 <.005 <.010

31 <.08 <.103 <.005 <.006 <.07 <.018 .018 <.010

32 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

33 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

34 <.08 <.103 <.005 <.006 <.07 .119 <.005 <.010

37 <.08 <.103 <.005 <.006 <.07 <.018 <.005 <.010

39 <.08 <.103 <.005 E.002 <.07 E.004 <.005 <.010

41 <.08 <.103 <.005 <.006 <.07 .262 <.005 E.012
58 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 12. Volatile organic compounds analyzed for in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Compound Parameter code Chemical Abstracts Service 

registry number

Laboratory reporting level 

(μg/L)

1,1,1,2-Tetrachloroethane 77562 630-20-6 0.03

1,1,1-Trichloroethane 34506 71-55-6 .03

1,1,2,2-Tetrachloroethane 34516 79-34-5 .09

1,1,2-Trichloroethane 34511 79-00-5 .06

1,1,2-Trichlorotrifluoroethane 77652 76-13-1 .06

1,1-Dichloroethane 34496 75-34-3 .07

1,1-Dichloroethylene 34501 75-35-4 .04

1,1-Dichloropropene 77168 563-58-6 .03

1,2,3,4-Tetramethylbenzene 49999 488-23-3 .2

1,2,3,5-Tetramethylbenzene 50000 527-53-7 .2

1,2,3-Trichlorobenzene 77613 87-61-6 .3

1,2,3-Trichloropropane 77443 96-18-4 .2

1,2,3-Trimethylbenzene 77221 526-73-8 .1

1,2,4-Trichlorobenzene 34551 120-82-1 .2

1,2,4-Trimethylbenzene 77222 95-63-6 .06

1,2-Dibromo-3-chloropropane 82625 96-12-8 .2

1,2-Dibromoethane 77651 106-93-4 .04

1,2-Dichlorobenzene 34536 95-50-1 .05

1,2-Dichloroethane 32103 107-06-2 .1

1,2-Dichloropropane 34541 78-87-5 .07

1,3,5-Trimethylbenzene 77226 108-67-8 .04

1,3-Dichlorobenzene 34566 541-73-1 .05

1,3-Dichloropropane 77173 142-28-9 .1

1,4-Dichlorobenzene 34571 106-46-7 .05

2,2-Dichloropropane 77170 594-20-7 .05

2-Butanone 81595 78-93-3 2

2-Chlorotoluene 77275 95-49-8 .04

2-Hexanone 77103 591-78-6 .7

3-Chloropropene 78109 107-05-1 .2

4-Chlorotoluene 77277 106-43-4 .06

4-Isopropyl-1-methylbenzene 77356 99-87-6 .07

4-Methyl-2-pentanone 78133 108-10-1 .4

Acetone 81552 67-64-1 7

Acrylonitrile 34215 107-13-1 1

Benzene 34030 71-43-2 .04

Bromobenzene 81555 108-86-1 .04

Bromochloromethane 77297 74-97-5 .04

Bromodichloromethane 32101 75-27-4 .05

Bromoform 32104 75-25-2 .06

Bromomethane 34413 74-83-9 .3

Butylbenzene 77342 104-51-8 .2

Carbon disulfide 77041 75-15-0 .07

Chlorobenzene 34301 108-90-7 .03

Chloroethane 34311 75-00-3 .1

Chloroform 32106 67-66-3 .05

Chloromethane 34418 74-87-3 .5

Dibromochloromethane 32105 124-48-1 .2

Dibromomethane 30217 74-95-3 .05

Table 12. Volatile organic compounds analyzed for in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Parameter code is used in U.S. Geological Survey National Water Information System database; —, no number]
Appendix 59

Dichlorodifluoromethane 34668 75-71-8 .3

Dichloromethane 34423 75-09-2 .4

Diethyl ether 81576 60-29-7 .2

Diisopropyl ether 81577 108-20-3 .1

Ethyl methacrylate 73570 97-63-2 .2

Ethyl tert-butyl ether 50004 637-92-3 .05

Ethylbenzene 34371 100-41-4 .03

Hexachlorobutadiene 39702 87-68-3 .1

Hexachloroethane 34396 67-72-1 .2

Isopropylbenzene 77223 98-82-8 .03

Methyl acrylate 49991 96-33-3 1

Methyl acrylonitrile 81593 126-98-7 .6

Methyl iodide 77424 74-88-4 .1

Methyl methacrylate 81597 80-62-6 .3

Naphthalene 34696 91-20-3 .2

Styrene 77128 100-42-5 .04

Tetrachloroethylene 34475 127-18-4 .1

Tetrachloromethane 32102 56-23-5 .06

Tetrahydrofuran 81607 109-99-9 2

Toluene 34010 108-88-3 .05

Trichloroethylene 39180 79-01-6 .04

Trichlorofluoromethane 34488 75-69-4 .09

Vinyl bromide 50002 593-60-2 .1

Vinyl chloride 39175 75-01-4 .1

cis-1,2-Dichloroethylene 77093 156-59-2 .04

cis-1,3-Dichloropropene 34704 10061-01-5 .09

m- and p-Xylene 85795 — .06

n-Propylbenzene 77224 103-65-1 .04

o-Ethyl toluene 77220 611-14-3 .06

o-Xylene 77135 95-47-6 .04

sec-Butylbenzene 77350 135-98-8 .03

tert-Butyl methyl ether 78032 1634-04-4 .2

tert-Butylbenzene 77353 98-06-6 .06

tert-Pentyl methyl ether 50005 994-05-8 .1

trans-1,2-Dichloroethylene 34546 156-60-5 .03

trans-1,3-Dichloropropene 34699 10061-02-6 .09

trans-1,4-Dichloro-2-butene 73547 110-57-6 .7

Table 12. Volatile organic compounds analyzed for in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Compound Parameter code Chemical Abstracts Service 

registry number

Laboratory reporting level 

(μg/L)
60 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 13. Concentration of volatile organic compounds detected in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; number below the parameter name is the U.S. Geological Survey National Water 

Information System parameter code; concentration reported in micrograms per liter; <, less than; E, estimated value; M, presence of compound verified but 

not quantified]

Well

identifier

Benzene1

(34030)

Bromodichloromethane

(32101)

Carbon 

disulfide

(77041)

Chloroform

(32106)

Chloromethane

(34418)

1,1-

Dichloroethane

(34496)

1,2-

Dichloroethane

(32103)

1,1-

Dichloroethylene

(34501)

Dichloromethane

(34423)

Ethylbenzene1

(34371)

o-Ethyltoluene1

(77220)

Methyl

tert-butyl 

ether

(MTBE)

(78032)

1 <0.04 0.27 <0.07 1.97 <0.5 <0.07 <0.1 <0.04 E0.1 <0.03 <0.06 <0.2

2 <.04 E.05 <.07 .55 <.5 E.03 <.1 E.01 <.4 <.03 <.06 <.2

3 <.04 E.02 <.07 E.08 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

4 <.04 <.05 E.05 .29 <.5 <.07 <.1 <.04 E.3 <.03 <.06 <.2

5 <.04 .16 <.07 .97 <.5 <.07 .4 <.04 M <.03 <.06 <.2

6 <.04 <.05 <.07 <.05 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

7 <.04 <.05 E.10 E.09 <.5 <.07 <.1 <.04 E.1 <.03 <.06 <.2

8 <.04 .24 <.07 1.16 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

9 <.04 E.07 <.07 .88 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

10 <.04 E.03 <.07 .18 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

11 <.04 <.05 <.07 E.03 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

14 <.04 E.04 <.07 .49 <.5 <.07 <.1 <.04 E.1 <.03 <.06 <.2

17 <.04 <.05 <.07 .94 <.5 <.07 <.1 <.04 M <.03 <.06 <.2

18 <.10 .19 <.37 1.53 <.2 <.07 <.1 <.04 <.4 <.03 <.10 <.2

20 <.04 .26 <.07 2.41 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

22 <.04 <.05 <.07 .10 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

24 <.04 .12 <.07 .64 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

25 <.04 .12 <.07 .65 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

26D <.10 E.03 <.37 .22 <.2 <.07 <.1 <.04 <.4 <.03 <.10 <.2

26S <.10 <.05 <.37 E.10 <.2 <.07 <.1 <.04 <.4 <.03 <.10 <.2

27 <.10 .51 <.37 2.11 <.2 <.07 <.1 <.04 <.4 <.03 <.10 E.1

29 <.17 <.24 <.35 <.26 <2.5 <.33 <.7 <.20 <1.9 <.15 <.30 <.8

30 <.04 .23 <.07 1.28 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

31 <.04 E.04 <.07 .31 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

32 M <.05 <.37 <.05 <.2 <.07 <.1 <.04 <.4 E.02 E.01 <.2

33 <.04 <.05 <.07 .13 <.5 <.07 <.1 E.05 <.4 <.03 <.06 <.2

34 E.01 <.05 <.37 E.03 E.1 <.07 <.1 <.04 <.4 E.01 <.10 <.2

37 <.10 <.05 E.01 .19 <.2 <.07 <.1 <.04 <.4 <.03 <.10 <.2

39 <.04 E.04 <.07 .24 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

41 <.04 <.05 <.07 E.06 <.5 <.07 <.1 <.04 <.4 <.03 <.06 <.2

1 Presence of compound in sample(s) may be the result of contamination. Compound was not included in analysis of volatile organic compound data.
Appendix 61

Table 13. Concentration of volatile organic compounds detected in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Well

identifier

Tetrachloroethylene

(PCE)

(34475)

Tetrachloromethane

(32102)

Toluene1

(34010)

1,1,1-

Trichloroethane

(TCA)

(34506)

Trichloroethylene

(TCE)

(39180)

Trichlorofluoromethane

(CFC-11)

(34488)

1,1,2-

Trichlorotrifluoroethane

(CFC-113)

(77652)

1,2,3-

Trimethylbenzene1

(77221)

1,2,4-

Trimethylbenzene1

(77222)

1,3,5-

Trimethylbenzene 1

(77226)

m- and pXylene1

(85795)

o-Xylene1

(77135)

1 4.8 <0.06 <0.05 E0.08 E0.04 <0.09 <0.06 <0.1 <0.06 <0.04 <0.06 <0.04

2 .1 <.06 <.05 .22 1.54 <.09 <.06 <.1 <.06 <.04 <.06 <.04

3 <.1 <.06 <.05 .12 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

4 M <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

5 7.8 <.06 <.05 <.03 E.06 <.09 <.06 <.1 <.06 <.04 <.06 <.04

6 <.1 <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

7 M <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

8 1.9 <.06 <.05 E.01 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

9 1.2 <.06 <.05 <.03 E.03 <.09 <.06 <.1 <.06 <.04 <.06 <.04

10 M <.06 <.05 E.05 E.02 <.09 <.06 <.1 <.06 <.04 <.06 <.04

11 <.1 <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 E.02 <.04

14 <.1 <.06 <.05 E.02 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

17 <.1 <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

18 .5 <.09 <.05 E.04 <.04 <.09 <.03 <.1 <.06 <.04 <.06 <.06

20 <.1 <.06 <.05 E.02 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

22 <.1 <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

24 <.1 <.06 <.05 E.04 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

25 M <.06 <.05 E.01 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

26D M <.09 <.05 <.03 <.04 <.09 <.03 <.1 <.06 <.04 <.06 <.06

26S <.1 <.09 <.05 <.03 <.04 <.09 <.03 <.1 <.06 <.04 <.06 <.06

27 .8 <.09 <.05 E.02 <.04 <.09 <.03 <.1 <.06 <.04 <.06 <.06

29 <.5 <.30 <.25 <.16 <.19 <.45 <.30 <.6 <.28 <.22 <.30 <.19

30 .6 <.06 <.05 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

31 M <.06 <.05 E.02 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

32 <.1 <.09 <.05 <.03 <.04 <.09 <.03 M E.03 E.01 E.08 E.02

33 <.1 <.06 <.05 .10 <.04 E.09 E.08 <.1 <.06 <.04 <.06 <.04

34 M <.09 E.01 <.03 <.04 <.09 <.03 <.1 E.01 <.04 E.03 <.06

37 <.1 <.09 <.05 E.01 <.04 E.04 <.03 <.1 <.06 <.04 E.01 <.06

39 <.1 E.01 <.05 E.01 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04

41 M <.06 E.01 <.03 <.04 <.09 <.06 <.1 <.06 <.04 <.06 <.04
62 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 14. Quality-control data for dissolved major ions in blank water and water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; numbers in bold indicate detection in the field-blank sample; mg/L, milligrams per 

liter; μg/L, microgram per liter; oC, degrees Celsius; number below parameter name is the U.S. Geological Survey National Water Information System 

parameter code; —, no data; <, less than; E, estimated value; M, presence of constituent is verified but not quantified]

Well

identifier

Sample

date

Sample

time

Sample

type

Bicarbonate

(mg/L

 as HCO3)

(00453)

Bromide

(mg/L as Br)

(71870)

Calcium

(mg/L as Ca)

(00915)

Chloride

(mg/L as Cl)

(00940)

Fluoride

(mg/L as F)

(00950)

26D 08/10/1999 1606 Field blank — <0.01 E0.01 <0.1 <0.1

26S 09/15/1999 1106 Field blank — <.01 .02 <.3 <.1

1 09/22/1999 1006 Field blank — <.01 <.02 <.3 <.1

22 09/29/1999 1106 Field blank — <.01 <.02 <.3 <.1

10 10/13/1999 1206 Field blank — <.01 <.02 <.3 <.1

31 10/21/1999 1106 Field blank — <.01 .02 <.3 <.1

34 09/09/1999 1100 Ground water 324 .10 99.8 101 .9

34 09/09/1999 1101 Replicate 324 <.01 100 100 .9

39 10/04/1999 1100 Ground water 363 .06 93.4 47.2 .5

39 10/04/1999 1101 Replicate 357 .06 93.4 47.0 .4

3 10/19/1999 1100 Ground water 360 .25 89.1 191 .6

3 10/19/1999 1101 Replicate 360 .24 86.8 185 .7

Well

identifier

Sample

date

Sample

time

Sample

type

Iron

(μg/L as Fe)

(01046)

Magnesium

(mg/L as Mg)

(00925)

Manganese

(μg/L as Mn)

(01056)

Potassium

(mg/L as K)

(00935)

Silica

(mg/L as SiO2)

(00955)

26D 08/10/1999 1606 Field blank <10 E.002 <3.0 <.10 <.1

26S 09/15/1999 1106 Field blank <10 <.014 <2.2 <.24 <.1

1 09/22/1999 1006 Field blank <10 <.014 <2.2 <.24 <.1

22 09/29/1999 1106 Field blank <10 <.014 <2.2 <.24 <.1

10 10/13/1999 1206 Field blank <10 <.014 <2.2 <.24 <.1

31 10/21/1999 1106 Field blank <10 E.008 <2.2 <.24 <.1

34 09/09/1999 1100 Ground water <10 30.0 <2.2 7.21 30.3

34 09/09/1999 1101 Replicate <10 30.4 E1.4 7.68 30.6

39 10/04/1999 1100 Ground water <10 25.8 18.7 5.76 20.8

39 10/04/1999 1101 Replicate <10 25.7 18.7 5.35 20.8

3 10/19/1999 1100 Ground water <10 53.7 2.2 14.4 38.4

3 10/19/1999 1101 Replicate <10 52.7 2.9 14.1 37.6

Well

identifier

Sample

date

Sample

time

Sample

type

Sodium

(mg/L as Na)

(00930)

Sulfate

(mg/L as SO4)

(00945)

Solids, residue

at 180 oC

(mg/L)

(70300)

Solids, sum of 

constituents

(mg/L)

(70301)

26D 08/10/1999 1606 Field blank M <.1 <10 —

26S 09/15/1999 1106 Field blank <.1 <.3 <10 —

1 09/22/1999 1006 Field blank <.1 <.3 <10 —

22 09/29/1999 1106 Field blank <.1 <.3 <10 —

10 10/13/1999 1206 Field blank <.1 <.3 <10 —

31 10/21/1999 1106 Field blank E.1 <.3 <10 —

34 09/09/1999 1100 Ground water 65.8 85.4 626 614

34 09/09/1999 1101 Replicate 63.6 84.6 552 578

39 10/04/1999 1100 Ground water 53.7 64.4 521 534

39 10/04/1999 1101 Replicate 53.0 64.3 531 528

3 10/19/1999 1100 Ground water 154 218 982 974

3 10/19/1999 1101 Replicate 152 218 960 962
Appendix 63

Table 15. Quality-control data for dissolved trace elements in blank water and water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; numbers in bold indicate detection in the field-blank sample; water samples for 

Radon-222 analysis were not filtered; μg/L, micrograms per liter; number below the parameter name is the U.S. Geological Survey National Water 

Information System parameter code; <, less than; M, presence of constituent is verified but not quantified; E, estimated value; pCi/L, picocuries per liter; 

—, no data]

Well 

identifier

Sample 

date

Sample 

time Sample type

Aluminum

(μg/L as Al)

(01106)

Antimony

(μg/L as Sb)

(01095)

Arsenic

(μg/L as As)

(01000)

Barium

(μg/L as Ba)

(01005)

Beryllium

(μg/L as Be)

(01010)

Cadmium

(μg/L as Cd)

(01025)

26D 08/10/1999 1611 Field blank <0.3 <0.20 <1.0 <0.2 <0.20 <0.30

26S 09/15/1999 1111 Field blank M <.20 <1.0 .2 <.20 <.30

1 09/22/1999 1011 Field blank <.3 <.20 <1.0 <.2 <.20 <.30

22 09/29/1999 1111 Field blank <.3 <.20 <2.0 <.2 <.20 <.30

10 10/13/1999 1211 Field blank <.3 <.20 <2.0 <.2 <.20 <.30

31 10/21/1999 1111 Field blank <.3 <.20 <2.0 <.2 <.20 <.30

34 09/09/1999 1109 Ground water 2 <1.00 <1.0 112 <1.00 <1.00

34 09/09/1999 1110 Replicate 2 <1.00 <1.0 113 <1.00 <1.00

39 10/04/1999 1109 Ground water 2 <1.00 3.3 130 <1.00 <1.00

39 10/04/1999 1110 Replicate 1 <1.00 3.1 131 <1.00 <1.00

3 10/09/1999 1109 Ground water 3 <1.00 12.2 28.3 <1.00 <1.00

3 10/09/1999 1110 Replicate 4 <1.00 12.6 27.9 <1.00 <1.00

Well

identifer

Sample

date

Sample

time Sample type

Chromium

(μg/L as Cr)

(01030)

Cobalt

(μg/L as Co)

(01035)

Copper

(μg/L as Cu)

(01040)

Lead

(μg/L as Pb)

(01049)

Molybdenum

(μg/L as Mo)

(01060)

Nickel

(μg/L as Ni)

(01065)

26D 08/10/1999 1611 Field blank .3 <.20 .7 <.30 <.2 1.04

26S 09/15/1999 1111 Field blank .3 <.20 .3 <.30 <.2 .51

1 09/22/1999 1011 Field blank .6 <.20 <.2 <.30 <.2 <.50

22 09/29/1999 1111 Field blank .3 <.20 .2 <.30 <.2 <.50

10 10/13/1999 1211 Field blank <.2 <.20 <.2 <.30 <.2 <.50

31 10/21/1999 1111 Field blank <.2 <.20 <.2 <.30 <.2 <.50

34 09/09/1999 1109 Ground water <1.0 <1.00 2.1 <1.00 7.5 3.39

34 09/09/1999 1110 Replicate <1.0 <1.00 1.9 <1.00 7.7 3.08

39 10/04/1999 1109 Ground water 1.5 <1.00 2.3 <1.00 3.4 3.24

39 10/04/1999 1110 Replicate 1.9 <1.00 2.3 <1.00 3.6 3.27

3 10/09/1999 1109 Ground water E.7 <1.00 1.3 <1.00 5.0 1.83

3 10/09/1999 1110 Replicate .9 <1.00 1.7 <1.00 5.0 2.09

Well 

identifier

Sample 

date

Sample 

time Sample type

Total radon-222

(pCi/L)

(82303)

Radon-222

2-sigma1

(pCi/L)

(76002)

Selenium

(μg/L as Se)

(01145)

Silver

(μg/L as Ag)

(01075)

Uranium

(μg/L as U)

(22703)

Zinc

(μg/L as Zn)

(01090)

26D 08/10/1999 1611 Field blank — — <1.0 <.2 <.20 3

26S 09/15/1999 1111 Field blank — — <1.0 <.2 <.20 6

1 09/22/1999 1011 Field blank — — <1.0 <.2 <.20 2

22 09/29/1999 1111 Field blank — — <2.4 <.2 <.20 1

10 10/13/1999 1211 Field blank — — <2.4 <.2 <.20 <.5

31 10/21/1999 1111 Field blank — — <2.4 <.2 <.20 M

34 09/09/1999 1109 Ground water 491 31 <1.0 <1.0 36.2 5

34 09/09/1999 1110 Replicate 499 31 <1.0 <1.0 36.7 4

39 10/04/1999 1109 Ground water 462 22 <2.4 <1.0 21.2 2

39 10/04/1999 1110 Replicate 536 23 <2.4 <1.0 21.5 2

3 10/09/1999 1109 Ground water 243 18 2.6 <1.0 5.29 2

3 10/09/1999 1110 Replicate 222 18 2.6 <1.0 5.37 4

12-sigma precision estimate.
64 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 16. Quality-control data for dissolved nutrient constituents and organic carbon in blank water and water sampled from monitoring wells in Salt 

Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; numbers in bold indicate detection in the field-blank sample; mg/L, milligrams per 

liter; number below the parameter name is the U.S. Geological Survey National Water Information System parameter code; <, less than; SS blank, sourcesolution blank; —, no data; E, estimated value]

Well 

identifier Sample date Sample time Sample type

Ammonia

(mg/L as N)

(00608)

Ammonia 

plus organic 

nitrogen

(mg/L as N)

(00623)

Organic 

carbon

(mg/L as C)

(00681)

Nitrite

(mg/L as N)

(00613)

Nitrite plus 

nitrate

(mg/L as N)

(00631)

Phosphorus

(mg/L as P)

(00666)

Orthophosphorus

(mg/L as P)

(00671)

26D 08/10/1999 1605 Field blank <0.020 <0.10 1.8 <0.010 <0.050 <0.004 <0.010

26D 08/10/1999 1607 SS blank — — <.10 — — — —

26S 09/15/1999 1105 Field blank <.020 <.10 1.5 <.010 <.050 <.004 <.010

26S 09/15/1999 1107 SS blank — — <.10 — — — —

1 09/22/1999 1005 Field blank <.020 E.06 .40 <.010 .117 <.004 <.010

1 09/22/1999 1007 SS blank — — <.10 — — — —

22 09/29/1999 1105 Field blank <.020 <.10 1.5 <.010 <.050 <.006 <.010

22 09/29/1999 1107 SS blank — — <.33 — — — —

10 10/13/1999 1205 Field blank .020 <.10 E.31 <.010 <.050 <.006 <.010

10 10/13/1999 1207 SS blank — — <.33 — — — —

31 10/21/1999 1105 Field blank <.020 E.06 .42 <.010 <.050 <.006 <.010

31 10/21/1999 1107 SS blank — — <.33 — — — —

39 10/04/1999 1100 Ground water <.020 .22 2.0 .012 9.96 .029 .027

39 10/04/1999 1101 Replicate <.020 .19 2.0 .012 9.61 .030 .020

3 10/19/1999 1100 Ground water <.020 .14 E1.1 <.010 8.55 .028 .028

3 10/19/1999 1101 Replicate <.020 .12 E.99 <.010 8.49 .029 .029
Appendix 65

Table 17. Quality-control data for selected dissolved pesticides in blank water, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; numbers in bold indicate detection in the field-blank sample; number below the 

parameter name is the U.S. Geological Survey National Water Information System parameter code; concentration reported in micrograms per liter; <, less 

than; M, presence of compound verified but not quantified; E, estimated value]

Well

identifier Sample date Sample time Sample type Atrazine1(39632)

Deethylatrazine1

(04040)

Deethyldeisopropylatrazine1, 2, 3

(04039)

Deisopropylatrazine1, 3

(04038)

2-Hydroxyatrazine1, 3

(50355)

Bromacil1, 3

(04029)

26D 08/10/1999 1605 Field blank <0.001 <0.002 <0.06 <0.07 <0.193 <0.08

26S 09/15/1999 1105 Field blank <.001 <.002 <.06 <.07 <.193 <.08

1 09/22/1999 1005 Field blank <.001 <.002 M <.07 <.193 <.08

22 09/29/1999 1105 Field blank <.001 <.002 <.06 <.07 <.193 <.08

10 10/13/1999 1205 Field blank <.001 <.002 <.06 <.07 <.193 <.08

31 10/21/1999 1105 Field blank <.001 <.002 <.06 <.07 <.193 <.08

Well

identifier Sample date Sample time Sample type Caffeine1, 3(50305)

Cycloate1, 2, 3

(04031)

Diazinon1

(39572)

Diuron1,3

(49300)

Fenuron2,3

(49297)

Imazaquin1,2,3

(50356)

26D 08/10/1999 1605 Field blank <.081 <.05 <.002 <.08 <.07 <.103

26S 09/15/1999 1105 Field blank <.081 <.05 <.002 <.08 <.07 <.103

1 09/22/1999 1005 Field blank <.081 <.05 <.002 <.08 M E.005

22 09/29/1999 1105 Field blank <.081 E.03 <.002 <.08 <.07 E.004

10 10/13/1999 1205 Field blank <.081 <.05 <.002 <.08 <.07 <.103

31 10/21/1999 1105 Field blank <.081 <.05 <.002 <.08 <.07 <.103

Well

identifier Sample date Sample time Sample type Malathion1(30532)

P,P' DDE1

(34653)

Picloram1, 3

(49291)

Prometon1

(04037)

Simazine1

(04035)

Tebuthiuron1

(82670)

26D 08/10/1999 1605 Field blank <.005 <.006 <.07 <.018 <.005 <.010

26S 09/15/1999 1105 Field blank <.005 <.006 <.07 <.018 <.005 <.010

1 09/22/1999 1005 Field blank <.005 <.006 <.07 <.018 <.005 <.010

22 09/29/1999 1105 Field blank <.005 <.006 <.07 <.018 <.005 <.010

10 10/13/1999 1205 Field blank <.005 <.006 <.07 <.018 <.005 <.010

31 10/21/1999 1105 Field blank <.005 <.006 <.07 <.018 <.005 <.010

1 Compound detected in one or more ground-water samples.

2 Compound detected in one or more blank-water samples.

3 Compound was analyzed by the high-performance liquid chromatography/mass spectrometry method before its final approval by the U.S. Geological 

Survey Office of Water Quality in 2001. Although the analytical method did not change following approval, data analyzed before method approval are 

considered provisional. Five of the six field-blank samples analyzed with this method exceeded the recommended 4-day holding time prior to sample 

extraction (Furlong and others, 2001). Degradation of pesticides during extended sample storage is likely, and concentrations and detection frequencies for 

the pesticides analyzed by this method may be biased low.
66 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 18. Quality-control data for selected volatile organic compounds in blank water, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; numbers in bold indicate detection in the field-blank sample; number below the 

parameter name is the U.S. Geological Survey National Water Information System parameter code; concentration reported in micrograms per liter; <, less 

than; SS blank, source-solution blank; E, estimated value; M, presence of constituent is verified but not quantified]

Well 

identifier Sample date Sample time Sample type Benzene1

(34030)

Bromodichloromethane1

(32101)

Carbon 

disulfide2

(77041)

Chloroform1

(32106)

Chloromethane1

(34418)

1,1-Dichloroethane1

(34496)

26D 08/10/1999 1605 Field blank <0.10 <0.05 <0.37 <0.05 <0.2 <0.07

26D 08/10/1999 1613 SS blank <.10 <.05 <.37 <.05 <.2 <.07

26S 09/15/1999 1105 Field blank <.10 <.05 E.20 <.05 <.2 <.07

26S 09/15/1999 1108 Trip blank <.10 <.05 <.37 <.05 <.2 <.07

26S 09/15/1999 1113 SS blank <.10 <.05 <.37 <.05 <.2 <.07

1 09/22/1999 1005 Field blank <.04 <.05 <.07 <.05 <.5 <.07

1 09/22/1999 1013 SS blank <.04 <.05 <.07 <.05 <.5 <.07

22 09/29/1999 1105 Field blank <.04 <.05 <.07 <.05 <.5 <.07

22 09/29/1999 1113 SS blank <.04 <.05 <.07 <.05 <.5 <.07

10 10/13/1999 1205 Field blank <.04 <.05 <.07 <.05 <.5 <.07

31 10/21/1999 1105 Field blank <.04 <.05 <.07 <.05 <.5 <.07

31 10/21/1999 1113 SS blank <.04 <.05 <.07 <.05 <.5 <.07

Well 

identifier Sample date Sample time Sample type

Tetrachloroethylene1

(PCE)

(34475)

Tetrachloromethane1

(32102)

Toluene1

(34010)

1,1,1-Trichloroethane1

(TCA)

(34506)

Trichloroethylene1

(TCE)

(39180)

Trichlorofluoromethane

(CFC-11)1

(34488)

26D 08/10/1999 1605 Field blank <.1 <.09 <.05 <.03 <.04 <.09

26D 08/10/1999 1613 SS blank <.1 <.09 <.05 <.03 <.04 <.09

26S 09/15/1999 1105 Field blank <.1 <.09 <.05 <.03 <.04 <.09

26S 09/15/1999 1108 Trip blank <.1 <.09 <.05 <.03 <.04 <.09

26S 09/15/1999 1113 SS blank <.1 <.09 <.05 <.03 <.04 <.09

1 09/22/1999 1005 Field blank <.1 <.06 <.05 <.03 <.04 <.09

1 09/22/1999 1013 SS blank <.1 <.06 <.05 <.03 <.04 <.09

22 09/29/1999 1105 Field blank <.1 <.06 <.05 <.03 <.04 <.09

22 09/29/1999 1113 SS blank <.1 <.06 <.05 <.03 <.04 <.09

10 10/13/1999 1205 Field blank <.1 <.06 <.05 <.03 <.04 <.09

31 10/21/1999 1105 Field blank <.1 <.06 <.05 <.03 <.04 <.09

31 10/21/1999 1113 SS blank <.1 <.06 <.05 <.03 <.04 <.09

1 Compound detected in one or more ground-water samples.

2 Compound detected in one or more ground-water and field-blank samples.
Appendix 67

Table 18. Quality-control data for selected volatile organic compounds in blank water, 1999—Continued

Well 

identifier Sample date Sample time Sample type

1,2-Dichloroethane1

(32103)

1,1-Dichloroethylene1

(34501)

Dichloromethane1

(34423)

Ethylbenzene2

(34371)

o-Ethyltoluene2

(77220)

Methyl tertbutyl ether

(MTBE)1

(78032)

26D 08/10/1999 1605 Field blank <0.1 <0.04 <0.4 E0.03 E0.01 <0.2

26D 08/10/1999 1613 SS blank <.1 <.04 <.4 <.03 <.10 <.2

26S 09/15/1999 1105 Field blank <.1 <.04 <.4 E.02 <.10 <.2

26S 09/15/1999 1108 Trip blank <.1 <.04 <.4 <.03 <.10 <.2

26S 09/15/1999 1113 SS blank <.1 <.04 <.4 <.03 <.10 <.2

1 09/22/1999 1005 Field blank <.1 <.04 <.4 <.03 <.06 <.2

1 09/22/1999 1013 SS blank <.1 <.04 <.4 <.03 <.06 <.2

22 09/29/1999 1105 Field blank <.1 <.04 <.4 E.01 M <.2

22 09/29/1999 1113 SS blank <.1 <.04 <.4 <.03 <.06 <.2

10 10/13/1999 1205 Field blank <.1 <.04 <.4 <.03 <.06 <.2

31 10/21/1999 1105 Field blank <.1 <.04 <.4 <.03 <.06 <.2

31 10/21/1999 1113 SS blank <.1 <.04 <.4 <.03 <.06 <.2

Well 

identifier Sample date Sample time Sample type

1,1,2-Trichlorotrifluoroethane

(CFC-113)1

(77652)

1,2,3- 

Trimethylbenzene2

(77221)

1,2,4-Trimethylbenzene2

(77222)

1,3,5-Trimethylbenzene2

(77226)

m- and pXylene2

(85795)

o-Xylene2

(77135)

26D 08/10/1999 1605 Field blank <.03 M E.06 E.02 E.15 E.03

26D 08/10/1999 1613 SS blank <.03 <.1 <.06 <.04 <.06 <.06

26S 09/15/1999 1105 Field blank <.03 <.1 <.06 <.04 E.10 <.06

26S 09/15/1999 1108 Trip blank <.03 <.1 <.06 <.04 <.06 <.06

26S 09/15/1999 1113 SS blank <.03 <.1 <.06 <.04 <.06 <.06

1 09/22/1999 1005 Field blank <.06 <.1 <.06 <.04 E.03 <.04

1 09/22/1999 1013 SS blank <.06 <.1 <.06 <.04 <.06 <.04

22 09/29/1999 1105 Field blank <.06 <.1 <.06 <.04 E.03 <.04

22 09/29/1999 1113 SS blank <.06 <.1 <.06 <.04 <.06 <.04

10 10/13/1999 1205 Field blank <.06 <.1 <.06 <.04 <.06 <.04

31 10/21/1999 1105 Field blank <.06 <.1 E.01 <.04 E.04 <.04

31 10/21/1999 1113 SS blank <.06 <.1 <.06 <.04 <.06 <.04
68 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 19. Percent recovery for pesticide surrogates in blank water and water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; number below the parameter name is the U.S. Geological Survey National Water 

Information System parameter code; all surrogate recoveries are reported in percent; E, estimated value]

Well 

identifier Sample date Sample time Sample type alpha-HCH-d6(91065)

Barban

(90640)

Caffeine1

(99959)

Diazinon

(91063)

2,4,5-T1

(99958)

26D 08/10/1999 1605 Field blank 102 81 102 101 96

26S 09/15/1999 1105 Field blank E175 E72 87 E197 48

1 09/22/1999 1005 Field blank 91 73 E107 111 61

22 09/29/1999 1105 Field blank 72 E80 E101 97 73

10 10/13/1999 1205 Field blank 99 89 50 134 47

31 10/21/1999 1105 Field blank 88 59 E80 124 59

1 09/22/1999 1000 Ground water 83 91 E99 105 64

2 09/20/1999 1400 Ground water 73 E94 70 90 58

3 10/19/1999 1100 Ground water 84 82 77 125 60

4 09/20/1999 1000 Ground water 89 E89 71 108 66

5 09/27/1999 1100 Ground water 92 E76 E81 95 66

6 10/07/1999 1100 Ground water 102 75 89 141 48

7 09/28/1999 1400 Ground water 83 E84 E90 96 73

8 10/18/1999 1200 Ground water 92 41 76 133 50

9 09/28/1999 1000 Ground water 90 E78 E86 100 71

10 10/13/1999 1200 Ground water 89 83 44 120 43

11 10/06/1999 1000 Ground water 89 73 68 124 E35

14 09/30/1999 1100 Ground water 79 E83 E87 111 66

17 09/23/1999 1100 Ground water 84 107 E90 97 62

18 09/13/1999 1200 Ground water 97 E104 78 101 60

20 10/05/1999 1200 Ground water 80 72 80 118 54

22 09/29/1999 1100 Ground water 78 62 82 107 E43

24 10/20/1999 1100 Ground water 84 53 E64 113 58

25 10/12/1999 1400 Ground water 97 96 44 139 54

26D 08/10/1999 1100 Ground water 106 76 93 103 101

26S 09/15/1999 1100 Ground water 73 E72 69 85 89

27 09/07/1999 1200 Ground water 84 E106 98 101 90

29 09/21/1999 1100 Ground water 83 E84 83 97 46

30 10/12/1999 1000 Ground water 95 85 45 128 56

31 10/21/1999 1100 Ground water 86 50 E66 119 61

32 09/14/1999 1100 Ground water 92 E93 79 101 82

33 10/14/1999 1000 Ground water 92 90 40 121 56

34 090/9/1999 1100 Ground water 89 E86 93 91 75

37 09/08/1999 1100 Ground water 99 E90 98 89 81

39 10/04/1999 1100 Ground water 88 60 81 123 E50

41 09/16/1999 1100 Ground water 85 E80 70 102 62

1Compound was analyzed by the high-performance liquid chromatography/mass spectrometry method before its final approval by the U.S. 

Geological Survey Office of Water Quality in 2001. Although the analytical method did not change following approval, data analyzed before method 

approval are considered provisional. Five of the 6 field-blank samples and 27 of the 30 ground-water samples analyzed with this method exceeded the 

recommended 4-day holding time prior to sample extraction (Furlong and others, 2001). Degradation of pesticides during extended sample storage is 

likely, and concentrations and detection frequencies for the pesticides analyzed by this method may be biased low.
Appendix 69

Table 20. Percent recovery for volatile organic compound surrogates in blank water and water sampled from monitoring wells in Salt Lake Valley, Utah, 

1999

[Well identifier corresponds to site shown in figure 3 and listed in table 6; number below the parameter name is the U.S. Geological Survey National Water 

Information System parameter code; all surrogate recoveries are reported in percent]

Well 

identifier Sample date Sample time Sample type

1,2-Dichloroethane-d4

(99832)

1,4-Bromofluorobenzene

(99834)

Toluene-d8

(99833)

26D 08/10/1999 1605 Field blank 99 86 94

26D 08/10/1999 1613 Source-solution blank 97 85 95

26S 09/15/1999 1105 Field blank 117 97 102

26S 09/15/1999 1108 Trip blank 112 92 100

26S 09/15/1999 1113 Source-solution blank 113 91 98

1 09/22/1999 1005 Field blank 119 97 103

1 09/22/1999 1013 Source-solution blank 112 98 104

22 09/29/1999 1105 Field blank 96 97 102

22 09/29/1999 1113 Source-solution blank 95 97 102

10 10/13/1999 1205 Field blank 105 86 95

31 10/21/1999 1105 Field blank 115 101 94

31 10/21/1999 1113 Source-solution blank 113 101 96

1 09/22/1999 1000 Ground water 116 95 103

2 09/20/1999 1400 Ground water 109 100 103

3 10/19/1999 1100 Ground water 109 73 93

4 09/20/1999 1000 Ground water 112 99 103

5 09/27/1999 1100 Ground water 97 98 102

6 10/07/1999 1100 Ground water 118 99 103

7 09/28/1999 1400 Ground water 95 96 101

8 10/18/1999 1200 Ground water 108 74 95

9 09/28/1999 1000 Ground water 96 99 102

10 10/13/1999 1200 Ground water 105 77 94

11 10/06/1999 1000 Ground water 118 88 101

14 09/30/1999 1100 Ground water 96 97 100

17 09/23/1999 1100 Ground water 121 101 104

18 09/13/1999 1200 Ground water 90 98 102

20 10/05/1999 1200 Ground water 112 98 99

22 09/29/1999 1100 Ground water 95 95 101

24 10/20/1999 1100 Ground water 113 100 91

25 10/12/1999 1400 Ground water 107 89 96

26D 08/10/1999 1100 Ground water 98 84 94

26S 09/15/1999 1100 Ground water 114 95 99

27 09/07/1999 1200 Ground water 95 98 101

29 09/21/1999 1100 Ground water 107 102 109

30 10/12/1999 1000 Ground water 109 79 93

31 10/21/1999 1100 Ground water 118 105 96

32 09/14/1999 1100 Ground water 88 99 104

33 10/14/1999 1000 Ground water 110 73 95

34 09/09/1999 1100 Ground water 91 103 104

37 09/08/1999 1100 Ground water 93 99 102

39 10/04/1999 1100 Ground water 109 87 98

41 09/16/1999 1100 Ground water 104 100 100
70 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

Table 21. Percent recovery for matrix spikes of pesticides in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Parameter 

code Compound

Recovery (percent)

Matrix spike

09/09/99

Matrix spike

10/04/99

Matrix-spike 

replicate

10/04/99

Matrix spike

10/19/99

Matrix-spike 

replicate

10/19/99

Gas Chromatography/Mass Spectrometry analytical method

49260 Acetochlor 109 104 101 107 102

46342 Alachlor 92 107 102 104 103

39632 Atrazine 89 86 82 93 93

82686 Azinphos-methyl 198 106 99 115 100

82673 Benfluralin 78 68 67 64 61

04028 Butylate 95 112 114 93 93

82680 Carbaryl 314 213 210 238 253

82674 Carbofuran 164 192 187 199 199

38933 Chlorpyrifos 83 84 79 89 86

04041 Cyanazine 106 81 77 78 73

82682 Dacthal 102 76 72 73 73

34653 p,p'-DDE 85 92 83 93 89

04040 Deethylatrazine 31 39 24 31 28

39572 Diazinon 85 113 110 122 115

39381 Dieldrin 108 123 116 112 109

82660 2,6-Diethylaniline 75 130 129 142 133

82677 Disulfoton 56 61 60 71 68

82668 EPTC 95 92 93 98 99

82663 Ethalfluralin 93 94 88 91 91

82672 Ethoprophos 86 71 70 69 63

04095 Fonofos 103 91 85 97 92

34253 alpha-HCH 83 104 98 109 109

39341 Lindane 91 99 93 118 105

82666 Linuron 218 163 158 150 137

39532 Malathion 108 90 88 85 80

39415 Metolachlor 116 101 97 96 95

82630 Metribuzin 88 114 100 105 105

82671 Molinate 90 101 103 100 103

82684 Napropamide 98 107 101 98 89

39542 Parathion 110 112 117 110 98

82667 Parathion-methyl 118 140 142 128 120

82669 Pebulate 93 92 94 96 95

82683 Pendimethalin 102 119 121 105 100

82687 cis-Permethrin 79 86 80 95 89

82664 Phorate 63 75 73 82 86

04037 Prometon 88 98 95 103 94

04024 Propachlor 107 99 107 102 102

82679 Propanil 117 95 93 93 86

82685 Propargite 105 82 78 84 93

82676 Propyzamide 95 90 85 85 82

04035 Simazine 115 93 88 92 88

82670 Tebuthiuron 90 90 96 89 86

82665 Terbacil 159 143 120 163 161

82675 Terbufos 76 69 67 70 64

82681 Thiobencarb 102 94 95 99 91

82678 Triallate 92 91 87 95 94

82661 Trifluralin 77 63 64 64 61

Table 21. Percent recovery for matrix spikes of pesticides in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Parameter code is used in U.S. Geological Survey National Water Information System database; —, no data]
Appendix 71

High-Performance Liquid Chromatography analytical method1

39732 2,4-D 74 37 42 57 57

50470 2,4-D methyl ester 79 52 54 43 56

38746 2,4-DB 69 24 42 39 43

50355 2-Hydroxyatrazine 165 122 131 132 134

61692 3(4-Chlorophenyl)-1-methyl urea 88 85 81 69 49

49308 3-Hydroxycarbofuran 112 85 84 64 69

50295 3-Ketocarbofuran 99 47 65 34 20

49315 Acifluorfen 71 75 69 73 74

49313 Aldicarb sulfone 50 6 4 23 22

49314 Aldicarb sulfoxide 52 29 27 26 42

39632 Atrazine 37 34 33 37 37

50299 Bendiocarb 96 71 73 33 37

50300 Benomyl 105 81 84 47 56

61693 Bensulfuron-methyl 137 108 113 80 89

38711 Bentazon 51 63 50 69 71

04029 Bromacil 81 61 59 53 54

49311 Bromoxynil 88 60 59 80 79

50305 Caffeine 96 83 84 70 79

49310 Carbaryl 87 85 86 70 76

49309 Carbofuran 102 93 96 73 79

61188 Chloramben, methyl ester 75 73 60 65 63

50306 Chlorimuron-ethyl 132 109 108 76 87

49306 Chlorothalonil 61 50 30 57 54

49305 Clopyralid 61 59 46 79 73

04031 Cycloate 94 73 78 51 59

49304 Dacthal monoacid 78 62 52 75 72

04040 Deethylatrazine 13 15 10 12 11

04039 Deethyldeisopropylatrazine 94 77 7 79 92

04038 Deisopropylatrazine 41 23 25 23 19

38442 Dicamba 84 54 43 94 88

49302 Dichlorprop 90 48 54 65 65

49301 Dinoseb 94 61 58 80 79

04033 Diphenamid 87 77 75 58 63

49300 Diuron 76 84 85 58 64

49297 Fenuron 56 58 69 56 72

61694 Flumetsulam 217 — — 123 140

38811 Fluometuron 88 82 82 63 69

50356 Imazaquin 180 120 122 51 55

50407 Imazethapyr — 120 129 111 101

61695 Imidacloprid 181 131 131 101 113

38478 Linuron 100 88 82 67 74

38482 MCPA 78 40 47 51 52

38487 MCPB 61 27 41 40 39

50359 Metalaxyl 90 83 82 59 66

38501 Methiocarb 96 83 85 67 74

49296 Methomyl 81 80 85 67 79

49294 Neburon 101 84 84 39 41

50364 Nicosulfuron 218 205 198 102 107

49293 Norflurazon 106 93 93 67 72

49292 Oryzalin 87 66 54 50 56

38866 Oxamyl 81 78 76 49 56

Table 21. Percent recovery for matrix spikes of pesticides in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Parameter 

code Compound

Recovery (percent)

Matrix spike

09/09/99

Matrix spike

10/04/99

Matrix-spike 

replicate

10/04/99

Matrix spike

10/19/99

Matrix-spike 

replicate

10/19/99
72 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

High-Performance Liquid Chromatography analytical method1—Continued

49291 Picloram 105 65 71 84 66

49236 Propham 107 87 86 86 91

50471 Propiconazole 95 92 94 45 49

38538 Propoxur 91 80 78 63 67

38548 Siduron 100 87 84 67 72

50337 Sulfometuron-methyl 145 124 121 73 75

82670 Tebuthiuron 37 36 39 36 34

04032 Terbacil 83 73 71 72 78

49235 Triclopyr 79 44 47 53 61

1 The samples from this study were analyzed by the high-performance liquid chromatography/mass spectrometry method before its final approval by 

the U.S. Geological Survey Office of Water Quality in 2001. Although the analytical method did not change following approval, data analyzed before 

method approval are considered provisional. All of the spiked samples analyzed with this method in this study exceeded the recommended 4-day holding 

time prior to sample extraction (Furlong and others, 2001). Degradation of pesticides during extended sample storage is likely, and concentrations and 

detection frequencies for the pesticides analyzed by this method may be biased low.

Table 21. Percent recovery for matrix spikes of pesticides in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—Continued

Parameter 

code Compound

Recovery (percent)

Matrix spike

09/09/99

Matrix spike

10/04/99

Matrix-spike 

replicate

10/04/99

Matrix spike

10/19/99

Matrix-spike 

replicate

10/19/99
Appendix 73

Table 22. Percent recovery for matrix spikes of volatile organic compounds in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—

Continued

Parameter 

code Compound

Recovery (percent)

Matrix spike

09/09/99

Matrix-spike 

replicate

09/09/99

Matrix spike 

10/04/99

Matrix-spike 

replicate

10/04/99

Matrix spike 

10/19/99

Matrix-spike 

replicate

10/19/99

81552 Acetone 106 106 116 109 102 111

34215 Acrylonitrile 103 105 94 105 104 99

34030 Benzene 100 100 80 86 84 85

81555 Bromobenzene 67 86 53 77 81 57

77297 Bromochloromethane 90 92 87 83 85 91

32101 Bromodichloromethane 130 110 97 116 98 91

50002 Bromoethene 56 49 45 44 36 40

32104 Bromoform 90 92 91 84 91 85

34413 Bromomethane 115 73 55 58 52 55

81595 2-Butanone 111 113 100 113 111 97

77342 Butylbenzene 90 87 72 75 68 71

77350 sec-Butylbenzene 77 86 74 84 73 74

77353 tert-Butylbenzene 77 84 87 81 74 77

77041 Carbon disulfide 106 119 97 85 92 100

34301 Chlorobenzene 85 94 69 83 81 77

34311 Chloroethane 117 110 81 96 91 72

32106 Chloroform 145 108 87 136 89 88

34418 Chloromethane 169 175 149 158 129 148

78109 3-Chloropropene 100 103 83 77 83 89

77275 2-Chlorotoluene 70 73 60 68 69 61

77277 4-Chlorotoluene 68 79 68 73 73 66

32105 Dibromochloromethane 96 101 88 92 92 85

82625 1,2-Dibromo-3-chloropropane 71 77 67 92 83 67

77651 1,2-Dibromoethane 90 91 85 85 86 88

30217 Dibromomethane 90 95 82 90 86 81

34536 1,2-Dichlorobenzene 77 83 80 87 75 74

34566 1,3-Dichlorobenzene 76 77 71 79 73 68

34571 1,4-Dichlorobenzene 76 82 81 81 72 73

73547 trans-1,4-Dichloro-2-butene 77 117 101 84 114 98

34668 Dichlorodifluoromethane 140 137 101 95 86 94

34496 1,1-Dichloroethane 109 105 80 90 89 85

32103 1,2-Dichloroethane 103 105 91 94 94 88

34501 1,1-Dichloroethylene 119 111 95 96 85 100

77093 cis-1,2-Dichloroethylene 94 94 65 82 75 79

34546 trans-1,2-Dichloroethylene 100 104 74 85 89 85

34423 Dichloromethane 93 89 83 80 74 83

34541 1,2-Dichloropropane 106 106 84 90 91 87

77173 1,3-Dichloropropane 103 104 96 101 97 94

77170 2,2-Dichloropropane 80 79 65 63 67 67

77168 1,1-Dichloropropene 102 98 67 82 79 76

34704 cis-1,3-Dichloropropene 84 93 71 77 77 77

34699 trans-1,3-Dichloropropene 80 89 71 75 78 73

81576 Diethyl ether 93 107 96 87 94 100

81577 Diisopropyl ether 88 100 71 82 90 76

34371 Ethylbenzene 79 89 54 85 76 62

73570 Ethyl methacrylate 80 107 74 79 100 79

50004 Ethyl tert-butyl ether 94 99 60 86 83 74

77220 o-Ethyl toluene 34 42 37 35 35 36

39702 Hexachlorobutadiene 62 80 76 71 65 73

Table 22. Percent recovery for matrix spikes of volatile organic compounds in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999

[Parameter code is used in U.S. Geological Survey National Water Information System database]
74 Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County, Utah

34396 Hexachloroethane 76 94 72 73 87 72

77103 2-Hexanone 97 108 95 102 107 93

77223 Isopropylbenzene 81 85 52 86 80 57

77356 4-Isopropyl-1-methylbenzene 33 38 33 33 32 33

49991 Methyl acrylate 101 105 89 104 100 88

81593 Methyl acrylonitrile 102 116 98 105 109 100

77424 Methyl iodide 91 125 80 72 99 78

81597 Methyl methacrylate 100 125 100 102 122 103

78133 4-Methyl-2-pentanone 102 107 96 104 99 103

78032 Methyl tert-butyl ether 92 112 79 90 102 86

50005 Methyl tert-pentyl ether 100 114 84 92 102 89

34696 Naphthalene 95 85 81 88 77 81

77224 n-Propylbenzene 82 79 68 82 70 67

77128 Styrene 75 83 53 84 81 56

77562 1,1,1,2-Tetrachloroethane 84 93 84 70 80 81

34516 1,1,2,2-Tetrachloroethane 94 96 94 100 96 87

34475 Tetrachloroethylene 96 105 90 87 83 92

32102 Tetrachloromethane 111 107 88 91 90 91

81607 Tetrahydrofuran 94 105 99 104 107 98

49999 1,2,3,4-Tetramethylbenzene 118 138 159 102 116 156

50000 1,2,3,5-Tetramethylbenzene 96 106 121 80 86 117

34010 Toluene 89 99 78 86 84 71

77613 1,2,3-Trichlorobenzene 100 90 84 80 77 82

34551 1,2,4-Trichlorobenzene 96 83 76 74 71 74

34506 1,1,1-Trichloroethane 109 101 85 94 88 86

34511 1,1,2-Trichloroethane 105 104 100 98 98 96

39180 Trichloroethylene 104 98 76 85 84 85

34488 Trichlorofluoromethane 101 110 96 94 87 96

77443 1,2,3-Trichloropropane 80 83 79 78 79 74

77652 1,1,2-Trichlorotrifluoroethane 105 105 88 86 85 92

77221 1,2,3-Trimethylbenzene 110 115 99 91 93 97

77226 1,3,5-Trimethylbenzene 95 88 75 87 72 73

77222 1,2,4-Trimethylbenzene 105 95 87 89 77 109

39175 Vinyl chloride 115 120 71 87 74 78

85795 m- and p-Xylene 86 92 61 95 86 65

77135 o-Xylene 79 90 56 87 84 61

Table 22. Percent recovery for matrix spikes of volatile organic compounds in water sampled from monitoring wells in Salt Lake Valley, Utah, 1999—

Continued

Parameter 

code Compound

Recovery (percent)

Matrix spike

09/09/99

Matrix-spike 

replicate

09/09/99

Matrix spike 

10/04/99

Matrix-spike 

replicate

10/04/99

Matrix spike 

10/19/99

Matrix-spike 

replicate

10/19/99
EXPLANATION

S.A. Thiros—Quality and Sources of Shallow Ground Water in Areas of Recent Residential Development in Salt Lake Valley, Salt Lake County,

Utah—Water-Resources Investigations Report 03–4028

National Water-Quality

Assessment program

study unit

Great Salt Lake Basins

study unit

Printed on recycled paper