PACIFIC OCEAN

Oceanside

Dana Point

MEXICO

UNITED STATES

San Diego

Data Series 129

California GAMA Program: Ground-Water Quality Data in the

San Diego Drainages Hydrogeologic Province, California, 2004

In cooperation with the

California State Water Resources Control Board

U.S. Department of the Interior

U.S. Geological Survey

Ground-Water Ambient Monitoring and Assessment (GAMA) Program

Temecula

Warner Springs
California GAMA Program: Ground-Water 

Quality Data in the San Diego Drainages 

Hydrogeologic Province, California, 2004

By Michael T. Wright, Kenneth Belitz, and Carmen A. Burton

Ground-Water Ambient Monitoring and Assessment (GAMA) Program

Data Series 129

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the California State Water Resources Control Board
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

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

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

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

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

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

endorsement by the U.S. Government.

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

reproduce any copyrighted materials contained within this report.

Suggested citation:

Wright, M.T.., Belitz, Kenneth, and Burton, C.A., 2005, California GAMA Program—Ground-water quality in the San 

Diego Drainages hydrogeologic province, California, 2004: U.S. Geological Survey Data Series 129, 91 p.
iii

Contents

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

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

Purpose and Scope ..............................................................................................................................4

Acknowledgments ...............................................................................................................................4

Hydrologic Setting of the San Diego GAMA Study Unit..........................................................................6

Temecula Valley Study Area ...............................................................................................................6

Warner Valley Study Area...................................................................................................................6

Alluvial Basins Study Area..................................................................................................................9

Hard Rock Study Area..........................................................................................................................9

Methods...........................................................................................................................................................9

Sampling Design ...................................................................................................................................9

Sample Collection...............................................................................................................................12

Sample Analysis..................................................................................................................................14

Data Reporting .......................................................................................................................14

Laboratory Reporting Conventions .........................................................................................14

Compounds on Multiple Analytical Schedules.....................................................................15

Quality Control ....................................................................................................................................15

Blanks .........................................................................................................................................15

Replicates ...................................................................................................................................16

Matrix Spikes..............................................................................................................................16

Surrogate Compounds .............................................................................................................16

Results. ..........................................................................................................................................................17

Quality-Control Samples....................................................................................................................17

Detections in Blanks .................................................................................................................17

Variability in Replicate Samples..............................................................................................17

Matrix Spike Recoveries ..........................................................................................................17

Surrogate Compound Recoveries...........................................................................................18

Ground-Water Quality ........................................................................................................................18

VOCs and Gasoline Oxygenates..............................................................................................19

Pesticides and Pesticide Degradates ....................................................................................19

Waste-Water Indicator Compounds.......................................................................................20

Perchlorate, NDMA, and 1,4-dioxane ....................................................................................20

Nutrients and Dissolved Organic Carbon ..............................................................................20

Major Ions and Total Dissolved Solids ...................................................................................20

Trace Elements...........................................................................................................................21

Isotopes, Radioactivity, and Noble Gases .............................................................................21

Microbial Constituents..............................................................................................................22

Summary........................................................................................................................................................22

References....................................................................................................................................................23

Tables.............................................................................................................................................................27
iv

Figures

Figure 1. Map showing hydrogeologic provinces of California. ............................................................3

Figure 2. Map showing San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study unit with locations of study areas....................................................................5

Figure 3. Map showing Temecula Valley study area and location of public-supply wells, 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study 

unit, California. ..............................................................................................................................7

Figure 4. Map showing Warner Valley study area and location of public-supply wells, 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study 

unit, California. ..............................................................................................................................8

Figure 5. Map showing alluvial Basins study area and location of public-supply wells, 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study

unit, California. ............................................................................................................................10

Figure 6. Map showing hard Rock study area and location of public-supply wells, 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) 

study unit, California...................................................................................................................11

Tables

Table 1. Classes of chemical and microbial constituents and water-quality indicators 

collected for the expanded, basic-plus, and basic sampling schedules in the 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) 

study, California, May to July 2004...........................................................................................28

Table 2A. Volatile organic compounds, primary use or source, Chemical Abstract 

Service (CAS) number, and laboratory reporting level (LRL) for the U.S. 

Geological Survey’s National Water Quality Laboratory analytical 

schedule 2020. ............................................................................................................................29

Table 2B. Gasoline oxygenates and gasoline oxygenate degradates, primary use 

or source, Chemical Abstract Service (CAS) number, and laboratory 

reporting level (LRL) for the U.S. Geological Survey’s National Water 

Quality Laboratory analytical schedule 4024 .........................................................................31

Table 2C. Pesticides and pesticide degradates, primary use or source, Chemical 

Abstract Service (CAS) number, and laboratory reporting level (LRL) for 

the U.S. Geological Survey’s National Water Quality Laboratory analytical 

schedule 2003..............................................................................................................................32

Table 2D. Pesticides, pesticide degradates, and caffeine, primary use or source, 

Chemical Abstract Service (CAS) number, and laboratory reporting level 

(LRL) for the U.S. Geological Survey’s National Water Quality Laboratory 

analytical schedule 2060. ..........................................................................................................34

Table 2E. Waste-water indicator compounds, primary use or source, Chemical 

Abstract Service (CAS) number, and laboratory reporting level (LRL) for 

the U.S. Geological Survey’s National Water Quality Laboratory analytical 

schedule 1433..............................................................................................................................36
v

Table 2F. Pharmaceutical compounds, primary use or source, Chemical Abstract 

Service (CAS) number, and method detection limit (MDL) for the U.S. 

Geological Survey’s National Water Quality Laboratory custom laboratory

code 9003. ....................................................................................................................................38

Table 2G. The emerging contaminant compounds perchlorate, 1,4-dioxane, and

 N-nitrosodimethylamine (NDMA), Chemical Abstract Service (CAS) 

number, and minimum reporting level (MRL) for Montgomery Watson 

Harza Laboratory.........................................................................................................................39

Table 2H. Nutrients and dissolved organic carbon, Chemical Abstract Service 

(CAS) number, and laboratory reporting level (LRL) for the U.S. Geological 

Survey’s National Water Quality Laboratory analytical schedule 2755 

and laboratory code 2613. .........................................................................................................39

Table 2I. Major ions and trace elements, Chemical Abstract Service (CAS) number, 

and laboratory reporting level (LRL) for the U.S. Geological Survey’s 

National Water Quality Laboratory analytical schedule 1948.............................................40

Table 2J. Iron, arsenic, and chromium speciation, Chemical Abstract Service 

(CAS) number, and method detection limit (MDL) for the U.S. Geological 

Survey’s National Research Program Laboratory, Boulder, Colorado...............................41

Table 2K. Isotopic and radioactive constituents, Chemical Abstract Service (CAS)

 number, reporting level type, reporting level/uncertainty, and reporting 

units for the U.S. Geological Survey’s National Water Quality Laboratory, 

Stable Isotope and Tritium Laboratory, Menlo Park, California, Stable Isotope

Lalboratory, Reston, Virginia, and the contract laboratories Eberline

Analytical Services and University of Arizona, Accelerator Mass

Spectrometry Laboratory ..........................................................................................................41

Table 2L. Tritium and noble gases, Chemical Abstract Service (CAS) number, method 

uncertainty (MU), and reporting units for Lawrence Livermore National 

Laboratory. ...................................................................................................................................42

Table 2M. Microbial constituents, primary use and source, and method detection 

limit (MDL) for the U.S. Geological Survey’s Ohio Microbiology Laboratory 

parameter codes 90901, 90900, 99335, and 99332..................................................................42

Table 3. Identification, sampling, and construction information for sampled wells 

in the San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study unit, California, May to July 2004. ..................................................................43

Table 4. Compounds analyzed for in ground-water samples collected for the San 

Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study,

California, May to July 2004, that appear on multiple analytical schedules, 

primary compound classification, analytical schedules compound appears 

on, and preferred analytical schedule ....................................................................................45

Table 5. Quality-control summary for volatile organic compounds and gasoline 

oxygenates, waste-water indicator compounds, emerging contaminant 

compounds, pesticide compounds, nutrients and dissolved organic carbon, 

major ions, and trace elements detected in trip blanks, equipment blanks, 

field blanks and ground-water samples collected for the San Diego GroundWater Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004 .........................................................................................................................46

Table 6A. Quality-control summary of replicate volatile organic compounds and 

gasoline oxygenates, pesticides and pesticide degradates, and emerging 

contaminant samples with relative standard deviations greater than zero, 

collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004....................................................47
vi

Table 6B. Quality-control summary of replicate nutrient and dissolved organic 

carbon samples collected for the San Diego Ground Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004........................48

Table 6C. Quality-control summary of replicate major ion samples collected for 

the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) 

study, California, May to July 2004...........................................................................................48

Table 6D. Quality-control summary of replicate trace-element samples collected 

for the San Diego Ground-Water Ambient Monitoring and Assessment

 (GAMA) study, California, May to July 2004..........................................................................49

Table 6E. Quality-control summary of replicate isotope and radioactivity samples 

collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004....................................................50

Table 7A. Quality-control summary of volatile organic compound, gasoline oxygenate, 

NDMA, and 1,4-dioxane matrix spike recoveries for samples collected for 

the San Diego Ground-Water Ambient Monitoring and Assessment

(GAMA) study, California, May to July 2004...........................................................................51

Table 7B. Quality-control summary of matrix pesticide spike recoveries for samples 

collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004....................................................54

Table 7C. Quality-control summary of matrix waste-water compound spike 

recoveries for samples collected for the San Diego Ground- Water 

Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004. ........................................................................................................................58

Table 8. Summary of surrogate compound recoveries for ground-water and 

quality-control analyses of volatile organic compounds, gasoline

oxygenates, pesticides and pesticide degradates, and waste-water 

indicator compound samples collected for the San Diego Ground- Water 

Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004. ........................................................................................................................59

Table 9. General water-quality parameters determined in the field for the San 

Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004. .....................................................................................................60

Table 10. Analysis for volatile organic compounds (VOCs) and gasoline oxygenates 

in ground-water samples collected in the San Diego Ground-Water 

Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004. ........................................................................................................................63

Table 11. Analysis for pesticides in ground-water samples collected for the San 

Diego Ground-Water Monitoring and Assessment (GAMA) study, California, 

May to July 2004 .........................................................................................................................67

Table 12. Analysis for waste-water indicator compounds in ground-water samples 

collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004....................................................71

Table 13. Analysis for emerging contaminant compounds perchlorate, 1,4-dioxane, and 

N-nitrosodimethylamine (NDMA) in ground-water samples collected in the 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004. ....................................................................................................72

Table 14. Analysis for nutrients and dissolved organic carbon in ground-water 

samples collected for the San Diego Ground-Water Ambient Monitoring 

nd Assessment (GAMA) study, California, May to July 2004. .............................................74
vii

Table 15. Analysis for major ions and total dissolved solids in ground-water samples 

collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004. ..................................................75

Table 16. Analysis for trace elements in ground-water samples collected for the 

San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) 

study, California, May to July 2004. .........................................................................................77

Table 17. Analysis for chromium, arsenic, and iron speciation by the U.S. Geological 

Survey National Research Progam in ground-water samples collected for 

the San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study, California, May to July 2004...........................................................................80

Table 18. Analysis for isotopes and radioactivity in ground-water samples 

collected for the San Diego Ground-Water Ambient Monitoring 

and Assessment (GAMA) study, California, May to July 2004............................................82

Table 19. Analysis for tritium and noble gases done at Lawrence Livermore 

National Laboratory in samples collected for the San Diego GroundWater Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004..........................................................................................................................85

Table 20. Microbial analysis of ground-water samples collected for the San Diego 

Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004......................................................................................................91

Conversion Factors, Abbreviations, and 

Acronyms

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Pressure

inch of mercury at 60oF (in Hg) 3.377 kilopascal (kPa) 

Radioactivity

picocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L) 
viii

SI to Inch/Pound

Multiply By To obtain

Length

kilometer (km) 0.6214 mile (mi)

Area

square kilometer (km2) 247.1 acre

square kilometer (km2) 0.3861 square mile (mi2)

Volume

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

liter (L) 0.2642 gallon (gal)

liter (L) 61.02 cubic inch (in3) 

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

 °C=(°F-32)/1.8

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

25°C).

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

or micrograms per liter (μg/L).

Abbreviations and Acronyms

mL milliliter

μL microliter

μm micrometer

pCi/L picocurie per liter

pCi/μg picocurie per microgram

AMCL alternative maximum contaminant level

CCV continuing calibration verification

DLR detection level for the purposes of reporting

DO dissolved oxygen

DOC dissolved organic carbon

GAMA Ground-Water Ambient Monitoring and Assessment program

LRL laboratory reporting level

LT-MDL long-term method detection level

MCL maximum contaminant level 

MDL method detection limit

MRL minimum reporting level

MTBE methyl tert-butyl ether
ix

N Normal

NAWQA National Water Quality Assessment Program

NDMA N-nitrosodimethylamine

NRP National Research Program

NWIS National Water Information System

PCE tetrachloroethylene

QC quality control

RSD relative standard deviation

SC specific conductance

SDALLV Alluvial Basins study area

SDHDRK Hard Rock study area

SDTEM Temecula Valley study area

SDWARN Warner Valley study area

SMCL secondary maximum contaminant level

TCE trichloroethylene

TDS total dissolved solids

THM trihalomethane

UCMR unregulated chemical for which monitoring is required

VOC volatile organic compound

 

 Organizations

DHS California Department of Health Services 

DWR California Department of Water Resources

LLNL Lawrence Livermore National Laboratory

NWQL National Water Quality Laboratory

SWRCB State Water Resources Control Board

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey
x
Abstract

Because of concerns over ground-water quality, the 

California State Water Resources Control Board (SWRCB), 

in collaboration with the U.S. Geological Survey and Lawrence Livermore National Laboratory, has implemented the 

Ground-Water Ambient Monitoring and Assessment (GAMA) 

Program. A primary objective of the program is to provide 

a current assessment of ground-water quality in areas where 

public supply wells are an important source of drinking water. 

The San Diego GAMA study unit was the first region of 

the state where an assessment of ground-water quality was 

implemented under the GAMA program. The San Diego 

GAMA study unit covers the entire San Diego Drainages 

hydrogeologic province, and is broken down into four distinct 

hydrogeologic study areas: the Temecula Valley study area, the 

Warner Valley study area, the Alluvial Basins study area, and 

the Hard Rock study area.

 A total of 58 ground-water samples were collected from 

public supply wells in the San Diego GAMA study unit: 19 

wells were sampled in the Temecula Valley study area, 9 in 

the Warner Valley study area, 17 in the Alluvial Basins study 

area, and 13 in the Hard Rock study area. Over 350 chemical 

and microbial constituents and water-quality indicators were 

analyzed for in this study. However, only select wells were 

measured for all constituents and water-quality indicators. 

Results of analyses were calculated as detection frequencies 

by constituent classification and by individual constituents for 

the entire San Diego GAMA study unit and for the individual 

study areas. Additionally, concentrations of constituents that 

are routinely monitored were compared to maximum contaminant levels (MCL) and secondary maximum contaminant 

levels (SMCL). Concentrations of constituents classified as 

“unregulated chemicals for which monitoring is required” 

(UCMR) were compared to the “detection level for the purposes of reporting” (DLR). 

Eighteen of the 88 volatile organic compounds (VOCs) 

and gasoline oxygenates analyzed for were detected in groundwater samples. Twenty-eight wells sampled in the San Diego 

GAMA study had at least a single detection of VOCs or 

gasoline oxygenates. These constituents were most frequently 

detected in the Alluvial Basin study area (11 of 17 wells), 

and least frequently detected in the Warner Valley study area 

(one of nine wells). Trihalomethanes (THMs) were the most 

frequently detected class of VOCs (18 of 58 wells). The most 

frequently detected VOCs were chloroform (18 of 58 wells), 

bromodichloromethane (8 of 58 wells), and methyl tert-butyl 

ether (MTBE) (7 of 58 wells). Three VOCs were detected at 

concentrations greater than their MCLs. Tetrachloroethylene 

(PCE) and trichloroethylene (TCE) were detected in one well 

in the Hard Rock study area at concentrations of 9.75 and 

7.27 micrograms per liter (μg/L), respectively; the MCL for 

these compounds is 5 μg/L. MTBE was detected in one well in 

the Alluvial Basins study area at a concentration of 28.3 μg/L; 

the MCL for MTBE is 13 μg/L. 

Twenty-one of the 122 pesticides and pesticide degradates analyzed for were detected in ground-water samples. 

Pesticide or pesticide degradates were detected in 33 of 

58 wells sampled, and were most frequently detected in the 

Temecula Valley study area wells (9 of 14 wells), and least 

frequently in the Warner Valley study area wells (3 of 9 wells). 

Herbicides were the most frequently detected class of pesticides (31 of 58 wells), and simazine was the most frequently 

detected compound (27 of 58 wells), followed by deethylatrazine (14 of 58 wells), prometon (10 of 58 wells), and atrazine 

(9 of 58 wells). None of the pesticides detected in groundwater samples had concentrations that exceeded MCLs.

Eight waste-water indicator compounds were detected in 

ground-water samples. Twenty-one of 47 wells sampled for 

waste-water indicator compounds had at least a single detection. Waste-water indicator compounds were detected most 

frequently in the Alluvial Basins study area (9 of 17 wells), 

and least frequently in the Temecula Valley study area (2 of 

6 wells). Phenol was the most frequently detected waste-water 

indicator compound (14 of 47 wells). Perchlorate was detected 

in 14 of 50 wells in the San Diego GAMA study; it was most 

frequently detected in Temecula Valley study area (7 of 

11 wells). 

California GAMA Program: Ground-Water Quality Data

in the San Diego Drainages Hydrogeologic Province, 

California, 2004

By Michael T. Wright, Kenneth Belitz, and Carmen A. Burton
Nitrate was detected in 17 of 24 wells at concentrations 

(0.1 to 9.14 mg/L) less than the MCL of 10 mg/L. Total dissolved solids (TDS) concentrations (148 to 1,800 milligrams 

per liter, or mg/L) exceeded the recommended secondary 

maximum contaminant level (SMCL) of 500 mg/L in 12 of the 

24 wells in which it was measured. The sample with the highest TDS also had concentrations of chloride (540 mg/L) and 

sulfate (421 mg/L) that exceeded recommended SMCL levels. 

Arsenic and uranium were detected in all 24 wells where 

they were measured. Arsenic concentrations ranged from less 

than 0.5 μg/L to 7.8 μg/L, and uranium concentrations ranged 

from 0.06 μg/L to 17.8 μg/L. The MCLs for these compounds 

are 50 and 30 μg/L, respectively. The MCL for arsenic will be 

reduced to 10 μg/L in 2006. Total dissolved chromium (total 

chromium) was detected in 44 of 50 wells, and hexavalent 

chromium in 36 of 50 wells. Total chromium concentrations 

did not exceed 5.7 μg/L, which is well below the 50 μg/L 

MCL for total chromium. However, hexavalent chromium was 

detected in 7 of 50 wells at concentrations greater than the 

detection level for the purposes of reporting (DLR); the DLR 

for hexavalent chromium is 1 μg/L. Boron was detected at 

concentrations (6 to 1,054 μg/L) greater than its DLR in 

15 of 24 wells, and vanadium was detected at concentrations 

(1 to 69 μg/L) greater than its DLR in 14 of 24 wells. Concentrations of iron (4 to 2,120 μg/L) and manganese (0.2 to 

492 μg/L) exceeded the SMCL in two and four wells, respectively. Mercury was not detected in any samples.

Radon-222 was detected in every ground-water sample 

in which it was analyzed for, with activities ranging from 180 

to 4,820 picoCuries per liter (pCi/L). The proposed MCL and 

alternative MCL for radon-222 is 300 and 4,000 pCi/L, respectively. Tritium was detected in nearly all samples; the highest 

activity detected was 23.7 pCi/L, which is well below the 

tritium MCL of 20,000 pCi/L. Radium-226 and radium-228 

were detected together in all but four ground-water samples. 

Activities detected for radium isotopes in ground water were 

low; radium-228 activities were below quantification levels in 

all but one sample. The combined MCL of 5 pCi/L for radium226 and radium-228 was not exceeded. 

Microbial constituents were analyzed in 24 ground-water 

samples. Total and Escherichia coliform were not detected in 

any samples. F-specific coliphage was detected in one sample 

collected in the Alluvial Basins study area. Somatic coliphage 

was detected in two ground-water samples, one in the Temecula Valley study area and one in the Warner Valley study area.

Introduction

Because of growing concerns over ground-water quality, 

the California State Water Resources Control Board (SWRCB) 

created the Ground-Water Ambient Monitoring and Assessment (GAMA) program. The GAMA program falls under 

the California Ground-Water Quality Monitoring Act of 

2001 (Sections 10780-10782.3 of the Water Code): a public 

mandate to assess and monitor the quality of ground water 

used as public supply for municipalities in California. The 

GAMA program is a compre­hensive assessment of California’s ground-water quality that is designed to help identify and 

understand risks to ground-water resources (Belitz and others, 

2003). The U.S. Geological Survey (USGS) is cooperating 

with the SWRCB, and partnering with the California Department of Health Services (DHS) and Lawrence Livermore 

National Laboratories (LLNL) in the implementation of the 

GAMA program. The three main objectives of GAMA are 

(1) to provide a current status of ground-water quality, (2) to 

detect changes in ground-water quality, and (3) to understand 

how anthropogenic and natural factors affect ground-water 

quality (Kulongoski and Belitz, 2004). Additionally, the 

GAMA program will analyze a broader suite of compounds at 

detection limits that are lower than those currently required by 

the DHS. The resulting information about chemical compounds and constituents, which is not normally available, may 

help in the early identification of contaminants that can impact 

ground-water quality. This early identification is a key aspect 

in the long-term management of ground-water resources.

An assessment of ground-water quality needs to be 

representative of the range of hydrologic, geologic, and 

climatic conditions that exist in California. Therefore, the 

state was divided into 10 hydrogeologic provinces (Belitz 

and others, 2003). Areas making up each hydrologic province 

have relatively similar hydrologic, geologic, and climatic 

characteristics (fig. 1). Each of these hydrogeologic provinces 

contains ground-water basins, which are generally composed 

of relatively permeable, unconsolidated deposits of alluvial or 

volcanic origin (California Department of Water Resources, 

2003). The GAMA program focuses primarily on groundwater basins that have public supply wells as an important 

source of drinking water. Eighty percent of the public supply 

wells in California are located in ground-water basins. The 

other 20 percent of public supply wells are located outside of 

ground-water basins in relatively low permeability rock (Belitz 

and others, 2003). The non-basin areas are also targeted by the 

GAMA program, thus allowing for a full assessment of the 

quality of ground water used for drinking-water supply.

2 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Figure 1. Hydrogeologic provinces of California.

Introduction 3

Basin and

Range

Central

Valley

Klamath

Mountains

Desert

Cascades and

Modoc Plateau

Transverse Ranges and

Selected Peninsular Ranges

Southern Coast

Ranges

Sierra

Nevada

Northern Coast

Ranges

San Diego

Drainages

Bakersfield

San Francisco

Sacramento

OREGON

NEVADA

MEXICO

A

RIZ

O

N

A

Redding

Los Angeles

San Diego

Pacific Ocean

0 200 MILES

0 200 KILOMETERS

40

42 124 122 120 118 116 114

38

36

34

Base from U.S Geological Survey digital elevation data,

1999, Albers Equal Area Conic Projection

Provinces from Belitz and others, 2004
Purpose and Scope

The purpose of this report is to present the results of 

analyses for organic and inorganic constituents and compounds, microbial constituents, and general water-quality 

indicators for ground-water samples collected for the San 

Diego GAMA study unit (fig. 2). The chemical and microbial 

data presented in this report are meant to characterize the quality of the untreated ground-water resources in this study unit 

and not the treated drinking water delivered to consumers by 

water purveyors. The chemical and microbial composition of 

treated drinking water may differ from untreated ground water 

in that treated drinking water might be subjected to disinfection, filtration, mixing with other waters, and exposure to the 

atmosphere prior to being delivered to the consumer.

 Fifty-eight public-supply wells were sampled in San 

Diego, Riverside, and Orange Counties from May to July 

2004. Three different sampling schedules (expanded, basic 

plus, and basic) were used in this study to collect chemical 

and microbial constituents (table 1). The following chemical 

and microbial constituents were analyzed for in this study: 88 

volatile organic compounds or VOCs (table 2A) and gasoline 

oxygenates (table 2B), 122 pesticides and pesticide degradates 

(table 2C and D), 63 waste-water indicator compounds 

(table 2E), 24 pharmaceutical compounds (table 2F), 

3 emerging contaminants [N-nitrosodimethylamine (NDMA), 

1,4-dioxane, and perchlorate] (table 2G), 5 nutrients and dissolved organic carbon (table 2H), 9 major ions (table 2I), 

25 trace elements, including reduction/oxidation speciation of 

arsenic, iron, and chromium (table 2I and J), 9 isotopic compounds (table 2K), 5 noble gases (table 2L), and the microbial 

constituents coliform and coliphage (table 2M). The following 

general water-quality indicators were determined: dissolved 

oxygen (DO), pH, specific conductance (SC), alkalinity, turbidity, and temperature.

Concentrations detected in ground-water samples for 

constituents that are regularly monitored by the DHS are 

compared to State and Federal drinking water standards. Any 

constituents exceeding either primary (MCL) or secondary 

maximum contaminant levels (SMCL) are highlighted in this 

report. MCLs are established with regard to the protection of 

human health, whereas SMCLs are established with regard to 

the aesthetic qualities of drinking water such as taste, odor, 

and color. In addition, detections of constituents classified 

by DHS as “unregulated chemicals for which monitoring is 

required” (UCMR) are highlighted if concentrations in ground 

water exceed the “detection level for the purposes of reporting” (DLR). The DLR is used for reporting constituents on the 

UCMR list because MCLs have yet to be determined for these 

chemicals. DLRs help in establishing MCLs by determining 

the extent of detections for the constituents of concern. 

Detection frequencies are reported for each anthropogenic, or man-made, constituent (VOCs, pesticides and pesticide degradates, waste-water indicator compounds, perchlorate, NDMA, and 1,4-dioxane) that is detected in at least one 

ground-water sample. Regulated, anthropogenic, and UCMRclassified constituents detected at a frequency greater than, 

or equal to, 10 percent are highlighted. Frequently detected 

constituents may be predictive of future changes in groundwater quality. 

Also presented in this report are the results and analysis of quality-control (QC) samples collected during the San 

Diego GAMA study. Results for pharmaceutical analyses of 

ground-water and quality-control samples will not be presented here, but instead will be published in a later report. This 

is because the pharmaceutical analytical method is still in the 

development stage and more quality-control data need to be 

collected in order to verify results. It is beyond the scope of 

this report to present a discussion of the factors that influence 

the distribution and occurrence of the chemical and microbial 

constituents detected in ground-water samples.

Acknowledgments 

The authors thank the following cooperators and partners 

for their support: California State Water Resources Control 

Board, California Department of Health Services, and Lawrence Livermore National Laboratory.

We also thank the following water purveyors for their 

generosity in letting the USGS collect samples from their 

water wells: Camp Pendleton Marine Base, Capistrano Valley Water District, City of Oceanside, County of San Diego, 

Del Dios Mutual Water Company, Elsinore Valley Municipal 

Water District, Julian Community Services District, Lake 

Cuyamaca Recreation and Park District, Lakeside Water 

District, Mataguay Scout Reservation, Mountain Empire High 

School, Murrieta County Water District, Oakvale RV Park, 

Ortega Oaks RV Park, Pala Rey Youth Camp, Palomar Mountain State Park, Pine Valley Mutual Water Company, Puerta La 

Cruz Conservation Camp, Ramona Municipal Water District, 

Rancho California Water District, Riverview Water District, 

Santa Margarita Water District, San Pasqual Academy, Sweetwater Authority, United States Forest Service, Vista Irrigation 

District, Warner High School, Warner Springs Ranch, Western 

Horizon’s-Ramona Canyon RV Resort, and Yuima Municipal 

Water District. 

4 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Figure 2. San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study unit with locations of study areas.

Introduction 5

PACIFIC OCEAN Santa

Margarita

River

San Luis Rey River

San Diego River

Sweetwater

River

117 30' 117 00' 116 30'

33

30'

33

00'

0 10 20 MILES

0 10 20 KILOMETERS

Oceanside

Dana Point

Temecula

MEXICO

UNITED STATES

ORANGE

COUNTY

PENINSULAR

RANGES

SAN DIEGO COUNTY

RIVERSIDE COUNTY

Base from U.S. Geological Survey digital elevation

data, 1999, Albers Equal-Area Conic Projection.

San Diego

EXPLANATION

Boundary of San Diego

Drainages Hydrogeologic

Province

Warner Valley study area

Temecula Valley study area

Hard Rock study area

Alluvial Basins study area

(yellow)

Desert Province

Transverse Ranges and Selected

Peninsular Ranges Province

Warner Springs
Hydrologic Setting of the San Diego 

GAMA Study Unit

The San Diego GAMA study unit was the first region 

where an assessment of ground-water quality was implemented under the GAMA program. The geographic boundaries of the study unit (fig. 2) are the same as those of the San 

Diego Drainages hydrogeologic province (Belitz and others, 

2003). The San Diego Drainages hydrogeologic province is 

described by the California Department of Water Resources 

(DWR) as the San Diego sub-hydrologic region, which corresponds to the southern portion of the South Coast hydrologic 

region (California Department of Water Resources, 2003). The 

San Diego GAMA study unit covers approximately 

3,900 square miles (mi2) of the southwestern corner of California, and includes most of San Diego County, and southwestern 

Orange and Riverside Counties. Twenty-seven ground-water 

basins are located within the San Diego GAMA study unit; 

these basins underlie approximately 433 mi2, or 11 percent, of 

the land surface. Boundaries of the San Diego GAMA study 

unit are the Transverse and Selected Peninsular Ranges province to the north, the Desert province to the east, the country 

of Mexico to the south, and the Pacific Ocean to the west. 

The climate in the coastal area of the San Diego GAMA 

study unit is generally mild, with temperatures averaging 

65 °F and average annual precipitation ranging from 10 to 

13 inches (in.) (California Regional Water Quality Control 

Board, San Diego Region, 1994). In the eastern portion of 

the study unit, annual temperatures in the Peninsular Ranges 

average in the mid fifties and average annual precipitation 

is approximately 45 in. The San Diego GAMA study unit is 

drained by a number of creeks and rivers, including the Santa 

Margarita and San Luis Rey Rivers in the north, and the San 

Diego and Sweetwater Rivers in the south. Runoff in the study 

unit is mainly due to rainfall; however, smaller amounts of 

runoff can be attributed to urban water use, snowmelt, and 

artesian springs. Ground- and surface-water flow primarily is 

from the mountainous east towards the west and the Pacific 

Ocean. .For the purposes of this study, the San Diego GAMA 

study unit consists of four study areas: the Temecula Valley 

study area, the Warner Valley study area, the Alluvial Basins 

study area, and the Hard Rock study area (fig. 2).

Temecula Valley Study Area

The boundaries of the Temecula Valley study area 

(fig. 3) are the same as those of the Temecula Valley Groundwater Basin (California Department of Water Resources, 

2004a). The Temecula Valley study area is located principally 

in southwestern Riverside County with a very small portion of 

the basin extending into northern San Diego County. The Temecula Valley study area covers 137 mi2

, and is bounded by the 

crystalline rock of the Peninsular Ranges on all sides, except 

in the northwest where it is bounded by the Elsinore groundwater basin. Average annual precipitation ranges from 7 to 

15 in. Surface-water drainage occurs by way of several creeks, 

including the ephemeral Temecula and Murrieta Creeks that 

discharge into the Santa Margarita River, which then flows 

westward out of the valley. The main water-bearing unit is 

Quaternary alluvium that is estimated to be up to 2,500 feet 

(ft) thick; it is generally unconfined except at deeper depths 

where it is semi-confined to confined (California Department 

of Water Resources, 1956). Sources of ground-water recharge 

in the basin include percolation of precipitation, infiltration of 

agricultural and domestic irrigation returns, and engineered 

recharge via spreading basins on Temecula Creek. 

Warner Valley Study Area

The boundaries of the Warner Valley study area 

(fig. 4) are the same as those of the Warner Valley Groundwater Basin, which is located in northeastern San Diego 

County (California Department of Water Resources, 2004b). 

The Warner Valley study area has a surface area of 37.5 mi2; 

it is bounded on the west by Lake Henshaw and on all other 

sides by the crystalline rocks of the Peninsular Ranges. Annual 

precipitation ranges from 15 to 21 in. The Warner Valley study 

area is drained by the ephemeral Agua Caliente and Buena 

Vista Creeks, as well as the San Luis Rey River, all of which 

flow westward into Lake Henshaw. The main water-bearing 

unit consists of residuum and alluvium (California Department 

of Water Resources, 1971). The alluvium is up to 900 ft thick 

and is generally unconsolidated. Sources of ground-water 

recharge include percolation of precipitation, and river and 

stream infiltration.

6 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Figure 3. Temecula Valley study area and location of public-supply wells, San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study unit, California.

Hydrologic Setting of the San Diego GAMA Study Unit 7

Santa Margarita River

Temecula Creek

Murrieta

Creek

RIVERSIDE COUNTY

SAN DIEGO COUNTY

Sampled public-supply well

Boundary of

San Diego

Drainages

Province

SDTEM-05

SDTEM-08

SDTEM-07

SDTEM-14

SDTEM-13

SDTEM-01

SDTEM-03

SDTEM-11

SDTEM-06

SDTEMFP-01

SDTEMFP-05

SDTEMFP-05

SDTEM-09

SDTEMFP-03

SDTEM-04

SDTEM-12

SDTEMFP-04

SDTEM-10

SDTEMFP-02 SDTEM-02

EXPLANATION

Public-supply well not sampled

Temecula Valley study area

0 2 4 MILES

0 2 4 KILOMETERS

117 15' 117 15' 30” 117 00'

33

37'

30”

33

30'

Temecula

Base from U.S. Geological Survey digital elevation

data, 1999, Albers Equal-Area Conic Projection.

Vail Lake

Lake Skinner

Sampled public-supply well

-Constituents detected at concentrations

greater than secondary maximum contaminant

level (SMCL) or detection level for the

purpose of reporting (DLR)
Figure 4. Warner Valley study area and location of public-supply wells, San Diego Ground-Water Ambient and Assessment (GAMA) 

study unit, California.

8 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004

Lake

Henshaw

San Luis Rey River

San Luis Rey

River

Agua Caliente Creek

Buena Vista Creek

Matagual Creek

Carrista Creek

..

.

....

.

.. .

. .

.

. .

.

.

..

..

.

.

.

.

.

.

.

.

!

!

!

!

!

!

!

!

.

.

.

.

.

.

.

.

.

0 2 4 MILES

0 2 4 KILOMETERS

Boundary of

San Diego

Drainages

Province

EXPLANATION

Warner Valley study area

116 45' 116 40' 116 35'

33

20'

33

15'

Base from U.S. Geological Survey digital elevation

data, 1999, Albers Equal-Area Conic Projection.

SDWARN-09

SDWARN-02

SDWARN-07

SDWARN-08

SDWARN-06

SDWARN-05

SDWARN-04

SDWARN-01

SDWARN-03

.

.

SDWARN-04

.

Sampled public-supply well

Public-supply well not sampled

Sampled public-supply well

-Constituents detected at concentrations

greater than secondary maximum contaminant

level (SMCL) or detection level for the

purpose of reporting (DLR)

Warner Springs
Alluvial Basins Study Area

The Alluvial Basins study area (fig. 5) consists of those 

DWR-defined alluvial basins in the San Diego Drainages 

study unit having one or more public supply wells. The 12 

ground-water basins composing this study area are the San 

Juan, San Mateo, Santa Margarita, San Luis Rey, San Pasqual, 

Santa Maria, San Diego River, El Cajon, Sweetwater, Cottonwood, Campo, and Potrero Valleys (California Department 

of Water Resources, 2003). The total surface area of the study 

area is approximately 166 mi2, with individual basins ranging 

in area from Potrero Valley, covering as little as 3.2 mi2 (California Department of Water Resources, 2004c), to the San Luis 

Rey Valley, covering as much as 46 mi2 (California Department of Water Resources, 2004d). Average annual precipitation ranges from 7 to 21 in. Runoff from precipitation primarily is drained to the southwest towards the Pacific Ocean, but 

some basins are internally drained. The main water-bearing 

units are Quaternary age alluvium and residuum, with an 

average thickness of alluvium that ranges from approximately 

50 ft in the San Mateo Valley ground-water basin (California Department of Water Resources, 1991) to 200 ft in the 

San Luis Rey ground-water basin (Izbicki, 1985). Sources 

of ground-water recharge include percolation of precipitation, river and stream infiltration, irrigation returns, spreading 

basins, discharge of waste water to rivers, and septic systems.

Hard Rock Study Area

The Hard Rock study area (fig. 6) consists of areas outside of ground-water basins that are within 3 kilometers (km) 

of a public-supply well. The study area covers approximately 

865 mi2, with the vast majority of the study area located in the 

inland areas of the study unit. Well completion reports for public-supply wells sampled in this study area show that wells are 

withdrawing water primarily from fractured granite. Sources 

of ground-water recharge include percolation of precipitation, 

and river and stream infiltration.

Methods

Sampling Design

Wells in the four study areas (figs. 3–6) of the San Diego 

GAMA study unit were designated with the following nomenclature: The Temecula Valley study area (SDTEM), the Warner Valley study area (SDWARN), the Alluvial Basins study 

area (SDALLV), and the Hard Rock study area (SDHDRK). 

Additional wells were sampled in the Temecula Valley study 

area to ascertain how ground-water quality is affected as it 

moves along two flow paths; these wells were given the designation SDTEMFP. Ground-water basins, as defined by DWR, 

were used for study area boundaries, except for the Hard Rock 

study area. A boundary for the Hard Rock study area was 

created by placing a 3-km radius buffer around public-supply 

wells that did not fall within any ground-water basin. A 

3-km radius was chosen because it would roughly equal one 

well per 25 square kilometers (km2), which is the desired sampling density for this study. 

The Temecula Valley ground-water basin was chosen 

as a study area because it is the largest basin, with the most 

public supply wells, of any basin in the San Diego Drainages 

hydrogeologic province. The Warner Valley ground-water 

basin was chosen as a study area because of its relatively 

pristine condition, isolated location, small population, and 

scant development. The Alluvial Basins study area consists of 

12 small to medium alluvial ground-water basins. By themselves, each alluvial ground-water basin has a small number 

of public supply wells that tap a small portion of the groundwater resources, but aggregated as one study area, the alluvial 

ground-water basins have a relatively large number of public 

supply wells that tap a large portion of the ground-water 

resources. Because there are a relatively large number of public supply wells outside ground-water basins in the San Diego 

GAMA study unit, the Hard Rock study area was created to 

assess water quality in fractured rock aquifers. 

Methods 9
Figure 5. Alluvial Basins study area and location of public-supply wells, San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study unit, California.

10 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004

PACIFIC OCEAN Santa

Margarita

River

San Luis Rey River

San Diego River

Sweetwater

River

..

. .

.. .. .

..

..

....

...

.. .

..

...

...... ..

... .... .

... ..........

...

.. .. .

..

...

....

. ......

.

..

.....

.

.

.

.

.. ...

....

.

... ... . .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

Oceanside

SDALLV-08

SDALLV-07

SDALLV-02

SDALLV-17

SDALLV-17

SDALLV-05

SDALLV-01

SDALLV-14

SDALLV-16

SDALLV-13

SDALLV-10

SDALLV-04

SDALLV-12

SDALLV-11

SDALLV-09

SDALLV-03

SDALLV-15

SDALLV-06

SDALLV-08

EXPLANATION

.

.

Boundary of San Diego

Drainages Hydrogeologic Province

Sampled public-supply well

Sampled public-supply wellConstituents detected at concentrations greater than maximum

contaminant level (MCL)

Sampled public-supply wellConstituents detected at concentrations greater than secondary

maximum contaminant level

(SMCL) or detection level for the

purpose of reporting (DLR)

Alluvial Basin well located

outside of Alluvial Basins study area

.

. Public-supply well not sampled

117 30' 117 00' 116 30'

0 10 20 MILES

0 10 20 KILOMETERS

Dana Point

Temecula

MEXICO

UNITED STATES

ORANGE

COUNTY

PENINSULAR

RANGES

SAN DIEGO COUNTY

RIVERSIDE COUNTY

San Diego

9-1 San Juan Valley

Alluvial basins (yellow areas on map) and State Hydrologic Region designation

9-2 San Mateo Valley

9-4 Santa Margarita Valley

9-7 San Luis Rey Valley

9-10 San Pasqual Valley

9-11 Santa Maria Valley

9-15 San Diego River Valley

9-17 Sweetwater Valley

9-27 Cottonwood Valley

9-28 Campo Valley

9-29 Potrero Valley

9-16 El Cajon Valley

9-11

9-10

9-16

9-15

9-17

9-28

9-27

9-29

9-1

9-2

9-4

9-7

Alluvial Basins study area

(see explanation below)

Desert Province

Transverse Ranges and Selected

Peninsular Ranges Province

33

30'

33

00'

Base from U.S. Geological Survey digital elevation

data, 1999, Albers Equal-Area Conic Projection.

Warner Springs
Figure 6. Hard Rock study area and location of public-supply wells, San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study unit, California.

Methods 11

PACIFIC OCEAN Santa

Margarita

River

San Luis Rey River

San Diego River

Sweetwater

River

SDHDRK-10

SDHDRK-02

SDHDRK-04

SDHDRK-12

SDHDRK-13 SDHDRK-07

SDHDRK-06

SDHDRK-08

SDHDRK-09

SDHDRK-03

SDHDRK-11

SDHDRK-05

SDHDRK-01

117 30' 117 00' 116 30'

33

30'

33

00'

0 10 20 MILES

0 10 20 KILOMETERS

EXPLANATION

Oceanside

Dana Point

Temecula

MEXICO

UNITED STATES

ORANGE

COUNTY

PENINSULAR

RANGES

SAN DIEGO COUNTY

RIVERSIDE COUNTY

Base from U.S. Geological Survey digital elevation

data, 1999, Albers Equal-Area Conic Projection.

San Diego

Boundary of San Diego

Drainages Hydrogeologic Province

Sampled public-supply well

Hard Rock well located outside

of Hard Rock study area

Sampled public-supply wellConstituents detected at concentrations

greater than maximum contaminant

level (MCL)

Sampled public-supply wellConstituents detected at concentrations

greater than secondary maximum contaminant level (SMCL) or detection

level for the purpose of reporting

(DLR)

Public-supply well not sampled

Hard Rock study area

SDHDRK-10

SDHDRK-01

Desert Province

Transverse Ranges and Selected

Peninsular Ranges Province

Warner Springs
The primary objectives in the selection of wells for 

GAMA study-area assessments are (1) to attain a sampling 

density of approximately one well per 25 km2, (2) randomly 

select at least 10 wells per study area whenever possible, and 

(3) minimize variability in well type (Gilliom and others, 

1995) . These objectives will help to assure an adequate and 

unbiased assessment of the quality of ground-water resources 

used for public supply. Additionally, since the GAMA 

program focuses on ground water used as a drinking-water 

resource (Belitz and others, 2003), public supply wells that 

are used for drinking water are the primary focus of sampling 

efforts. The GAMA framework does allow irrigation, domestic, and/or monitoring wells to be sampled if needed to obtain 

adequate spatial coverage in a study unit. In the San Diego 

GAMA study unit, public supply wells provide good spatial 

coverage; therefore, domestic, irrigation, or monitoring wells 

were not part of the selection process. Wells with available 

construction information (well depth, depth of perforations, 

date constructed) were given priority for sampling. 

Wells were selected for each study area using a gridbased program that produced random, equal-area cells (Scott, 

1990). The program was used to generate 20 cells in the Temecula Valley study area, 10 cells in the Warner Valley study 

area, 20 cells in the Alluvium Basins study area, and 10 cells 

in the Hard Rock study area. Where a cell had multiple wells, 

each well in that cell was randomly assigned a rank. For each 

particular cell with multiple wells, the lowest ranked well was 

given priority for sampling. An attempt was made to select 

one well per cell, but this was not always possible. Wells from 

adjacent cells were used to populate cells that either had no 

active wells or contained wells that did not meet the selection criteria, such as those lacking well-construction data. The 

exception to the one well sampled per cell criterion was in 

the Temecula Valley study area where additional wells were 

sampled in cells that were important to the flow path study.

Wells were sampled for either an “expanded,” “basic 

plus,” or “basic” schedule (table 1). Expanded schedule sampling entails collecting samples for analysis of a large number 

of chemical and microbial constituents and field measurable 

water-quality indicators. Consequently, sampling wells for 

an expanded schedule requires a substantial investment of 

time and labor. Wells that were located in areas of interest, 

such as along flow paths, were given priority for expanded 

schedule sampling. Initially, approximately 50 percent of the 

wells in the San Diego GAMA study were to be sampled for 

an expanded schedule, and 50 percent for the basic schedule. 

However, after completion of sampling in the first study area, 

the Temecula Valley, it was apparent that sampling 50 percent 

of the wells for an expanded schedule would be too time consuming. Therefore, for the other three study areas, the number 

of wells sampled for the expanded schedule was decreased 

to approximately 30 percent. To help adjust for the smaller 

number of wells sampled for the expanded schedule, the basic 

schedule was enhanced to include some compounds that were 

previously only collected for the expanded schedule. This 

basic-plus schedule did not significantly increase sampling 

time, yet allowed for a greater number of constituents to be 

collected than if the basic schedule had been used.

Sample Collection

Table 2A−M shows the names of chemical and microbial 

constituents analyzed for in the ground-water samples from 

wells in the San Diego GAMA study unit. Table 3 gives the 

date and time that each well was sampled, along with the 

type of sampling schedule and well construction information. 

Samples were collected from 58 public supply wells from 

May to July 2004. Of the 58 wells sampled, 19 were in the 

Temecula Valley study area, 17 in the Alluvial Basins study 

area, 13 in the Hard Rock study area, and 9 in the Warner 

Valley study area. Twenty wells were scheduled to be sampled 

in the Alluvial Basins study area, but a review of the well 

completion reports showed that three of the wells sampled in 

this study area were withdrawing water from fractured rock, 

so these wells were reassigned to the Hard Rock study area 

(fig. 6). Additionally, a well that was originally located in the 

Hard Rock study area was switched to the Alluvial Basins 

study area (fig. 5) when a review of the well completion report 

showed that the well was withdrawing from an alluvial aquifer. Neither of these changes significantly affected the target 

sampling density for either the Alluvial Basins or Hard Rock 

study areas. Because of well availability, only nine wells were 

sampled in the Warner Valley study area. These nine wells 

provided good spatial distribution (fig. 4). 

Sampling procedures utilized by the USGS National 

Water Quality Assessment (NAWQA) program were implemented in this study to mitigate the potential for airborne contamination of samples and (or) cross contamination between 

wells (Koterba and others, 1995; U.S. Geological Survey, 

1998; U.S. Geological Survey, 1999). Before the onset of sample collection, a set procedure was followed to help assure that 

a representative sample of ground water would be collected at 

each site; the procedure used was dependent on the sampling 

schedule employed at each particular site. If a site was to be 

sampled for a basic or basic-plus schedule, then the well was 

pumped continuously for a minimum of 20 minutes in order 

to purge the well of at least three casing-volumes of water. If a 

site was to be sampled for the expanded schedule, then ground 

water was pumped through a flow-through chamber fitted 

with a multi-probe meter that is able to simultaneously measure these water-quality indicators: dissolved oxygen (DO), 

temperature, pH, turbidity, and electrical conductivity (EC). 

Measurements were taken at 5-minute intervals; sampling did 

not begin until the water-quality indicators remained stable for 

at least 20 minutes. 

12 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Samples were collected by affixing Teflon tubing to 

the sampling point closest to the well head using stainless 

steel fittings. If a site was sampled for a basic, or basic-plus 

schedule, the sample was collected at the well head using a 

foot-long section of Teflon tubing. If a site was sampled for 

the expanded schedule, the sample was collected inside an 

enclosed chamber that was located in a mobile water-quality laboratory. The length of the Teflon tubing used for the 

expanded schedule ranged from 10 to 50 ft. All but two 

samples at a well were collected before any type of filtration or chemical treatment, such as chlorination, was done to 

the ground water. Chlorination of ground water that contains 

DOC may form trihalomethanes (THMs). Ground water from 

one well, SDHDRK-05, was passed through a sediment filter 

before the sampling port. This was not considered to have a 

significant effect on the water-quality assessment of this site. 

Two wells, SDHDRK-05 and SDALLV-16, had chlorination 

equipment in the well bore. The chlorinator for SDHRDK-05 

was shut off, and the well was pumped for eight hours prior to 

sampling. Before sampling SDALLV-16, the well was pumped 

for one hour with the chlorinator shut off. The samples from 

both SDHDRK-05 and SDALLV-16 had THM detections.

 Filtering of samples in the field was done using a 

0.45-μm capsule or disk filter. Polyethylene bottles were prerinsed with native water before sample collection. Samples 

requiring preservation with acid had the pH lowered to 2 or 

below. All samples were kept on ice and shipped immediately 

to the laboratory for analyses, except for samples collected for 

the analysis of chromium species, tritium, noble gases, stable 

isotopes of water, and carbon isotopes. Radium isotopes, gross 

alpha/beta radiation, and radon-222 samples were not kept on 

ice, but were shipped immediately after collection. 

 Volatile organic compounds and gasoline oxygenates 

were collected in 40-mL sample vials that were purged using 

three vial volumes of sample water and then bottom filled to 

eliminate headspace. Six normal (N) hydrochloric acid (HCl) 

was added to the VOC samples, but not the gasoline oxygenate samples, as a preservative. Samples for stable isotopes of 

water were collected by filling a 60-mL clear glass bottle with 

unfiltered water, sealing with a conical cap, and securing with 

electrical tape to prevent leakage and evaporation. Samples 

for pesticides, pesticide degradation products, waste-water 

indicator compounds, pharmaceuticals, NDMA, and 1,4-dioxane were collected in 1-L baked amber bottles; these samples 

were not filtered in the field, but at their respective laboratories 

prior to analysis. Samples for major ions and trace elements 

were collected by filtering ground water into two 250-mL 

polyethylene bottles, and then preserving (the trace elements 

sample bottle only) with 7.5N nitric acid. Radium isotopes and 

gross alpha/beta samples were collected and preserved in the 

same manner as for trace elements, except 2- and 1-L aliquots 

of ground water were collected, respectively. Mercury samples 

were collected by filtering ground water into a 250-mL glass 

bottle and preserving with 6N HCl. Arsenic and iron speciation samples were filtered into a 250-mL polyethylene bottle 

that was taped so the sample was not exposed to light; the 

sample was preserved with 6N HCl. Nutrient and perchlorate 

samples were each filtered into 

125-mL polyethylene bottles. Carbon isotope samples were 

filtered and bottom filled into two 500-mL baked glass 

containers that were first purged using three bottle volumes 

of ground water. These samples had no headspace, and were 

sealed with a conical cap to resist evaporation. Samples for 

alkalinity were collected by filtering ground water into a 500-

mL polyethylene bottle. Tritium samples were collected by 

bottom filling two 1-L bottles with unfiltered ground water, 

after first purging the bottle of three volumes of water.

Four constituents (chromium, DOC, radon-222, and 

noble gases) were collected at the well head, regardless of the 

sampling schedule (expanded, basic-plus, or basic). Samples 

collected for total dissolved chromium (total chromium) and 

hexavalent chromium were taken directly from the sampling 

port. For total chromium, a 10-mL syringe that had a small 

0.45-mm disk filter connected directly to it was filled with 

ground water and 2 mL of the ground water was filtered into 

a small centrifuge tube. To collect the hexavalent chromium 

sample, a small ion-exchange column was attached to the disk 

filter and 2 mL of ground water was filtered into a second 

centrifuge vial. Both vials were preserved with 10 mL of 7.5N 

nitric acid (Ball and McClesky, 2003a). 

DOC was collected by filling a 50-mL syringe, that had a 

0.45-μm disk filter connected directly to it, with ground water 

directly from the sampling port at the well head. The ground 

water was then filtered into a 125-mL baked glass bottle and 

preserved with 4.5N sulfuric acid. For the collection of radon222, a stainless steel and Teflon valve assembly was attached 

to the sampling port at the well head. The valve was partially 

closed, and a 10-mL sample was taken through a Teflon septum on the valve assembly using a glass syringe affixed with 

a stainless steel needle. The sample was then injected into a 

25-mL vial partially filled with scintillation cocktail. The vial 

was then placed in a cardboard tube in order to shield it from 

light during shipping (U.S. Geological Survey, 1999). 

To collect noble gases, reinforced nylon tubing was 

attached to the sampling port at the well head. The reinforced 

tubing was attached to an approximately 12-in.-long, 3/8-in. 

ID copper tube with a back pressure valve attached to the other 

end. The copper tube was affixed to a metal plate with two 

clamps. Ground water was run through the copper tube, while 

it was firmly tapped for approximately 45 seconds. This was 

done to remove any gas bubbles that may have been trapped 

inside the tube. The back pressure valve was then closed 

almost completely, and the clamps tightened down in order to 

trap a sample of ground water with its associated noble gases 

(Weiss, 1968).

Methods 13
Samples for microbial constituents also were collected at 

the well head. Prior to the collection of samples, the sampling 

port was sterilized with isopropyl alcohol, and ground water 

was run through the sampling port for at least three minutes to 

remove any traces of the sterilizing agent. Two 250-mL sterilized bottles were then filled for the coliform samples (total and 

Escherichia coliform determinations), and one 3-liter sterilized 

carboy was filled for the coliphage samples (F-specific and 

somatic coliphage determinations).

Sample Analysis

Nine laboratories performed chemical and microbial 

analyses for the San Diego GAMA study. The following 

analytical methods were used for the determination of organic 

and inorganic constituents by the USGS National Water-Quality Laboratory (NWQL): VOCs by purge and trap capillary 

gas chromatography/mass spectrometry (Conner and others, 

1998); gasoline oxygenates by heated purge and trap/gas chromatography/mass spectrometry (Rose and Sandstrom, 2003); 

pesticides by solid-phase extraction and chromatography/mass 

spectrometry (Furlong and others, 2001; Sandstrom and others, 2001); waste-water indicator compounds by polystyrenedivinylbenzene solid-phase extraction and capillary-column 

gas chromatography/mass spectrometry (Zaugg and others, 

2002); pharmaceutical compounds by solid-phase extraction 

and high-performance liquid chromatography–electrospray 

ionization mass spectrometry (Cahill and others, 2004); major 

ions, trace elements, and nutrients by several methods (Fishman and Friedman, 1989; Fishman, 1993; McLain, 1993; 

Garbarino, 1999; Garbarino and Damrau, 2001; Patton and 

Kryskalla, 2003); DOC by UV-promoted persulfate oxidation 

and infrared spectrometry (Brenton and Arnett, 1993); and 

radon-222 by liquid scintillation counting (American Society 

for Testing and Materials, 1992).

The following methods were used for the determination of organic and inorganic and microbial constituents by 

laboratories other than the NWQL: Perchlorate, NDMA, 

and 1,4-dioxane analysis by Montgomery Watson and Harza 

Laboratory using chromatography and mass spectrometry 

(U.S. Environmental Protection Agency, 1996; Hautman and 

others, 1999; U.S. Environmental Protection Agency, 1999); 

stable isotopes of water by the USGS Reston Stable Isotope 

Laboratory using gaseous hydrogen and carbon dioxide-water 

equilibration (Epstein and Mayeda, 1953; Coplen and others, 

1991); chromium, iron, and arsenic analysis by the USGS 

NRP laboratory in Boulder, Colorado, using various techniques of UV-VIS spectrophotometry and atomic absorbance 

spectroscopy (Stookey, 1970; To and others, 1998; Ball and 

McCleskey, 2003b; McCleskey and others, 2003); F-specific 

and somatic coliphage analysis by the USGS Ohio Microbiology Laboratory (U.S. Environmental Protection Agency, 

2000a); tritium analysis at the USGS NRP laboratory in Menlo 

Park, California, using electrolytic enrichment-liquid scintillation method (Thatcher and others, 1977); tritium (helium 

in-growth method) and noble gases analyzed by LLNL (Eaton 

and others, 2004); radium-226, radium-228, gross alpha 

and beta radioactivity analysis by Eberline Analytical Services using several methods (U.S. Environmental Protection 

Agency, 1980); carbon isotopes analysis by the University of 

Arizona Accelerated Mass Spectrometry Laboratory (Donahue 

and others, 1990; Jull and others, 2004); and total and Escherichia coliform analyzed by USGS field personnel using the 

MI method (U.S. Environmental Protection Agency, 2002b).

Data Reporting

Laboratory Reporting Conventions

The NWQL uses laboratory reporting levels (LRLs) for 

reporting non-detections of constituents, but also is able to 

semi-quantitatively detect compounds below the LRL. The 

LRL and long-term method detection level (LT-MDL) are 

calculated on the basis of QC experiments conducted by the 

NWQL. The LT-MDL mitigates the reporting of false positive 

readings. The risk of reporting a false positive concentration 

equal to or greater than the LT-MDL when the constituent is 

not present is 1 percent or less. The LRL (LRL = 2 × LTMDL) is used to minimize the chance of reporting a false 

negative reading. The risk of reporting a false negative is 

1 percent or less when the actual concentration is equal to or 

greater than the LRL (Childress and others, 1999).

Some constituent concentrations in this study are reported 

using method detection limits (MDLs), minimum reporting 

levels (MRLs), and method uncertainties. The MDL serves the 

same purpose as the LT-MDL: to reduce the risk of reporting false positives (U.S. Environmental Protection Agency, 

2002a). The risk of reporting a false positive concentration 

equal to or greater than the MDL when the constituent is not 

present is also 1 percent or less. However, the methods for 

establishing the LT-MDL are more robust than those used 

to establish the MDL. Therefore, the LT-MDL may be more 

representative of true method detection limits. The MRL is the 

smallest measurable concentration of a constituent that may 

be reliably reported using a given analytical method (Timme, 

1995). The method uncertainty generally indicates the precision of a particular analytical measurement; it gives a range of 

values wherein the true value will be found.

14 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compounds on Multiple Analytical Schedules

Twenty-two constituents targeted in the San Diego 

GAMA study were determined by more than one analytical 

schedule (table 4). Certain analytical schedules are “preferred” 

over others because the methodology is more accurate and 

precise, and generally yields a greater sensitivity for a given 

constituent. If a constituent appears on multiple analytical 

schedules, then only the detections determined by the preferred analytical schedule are given in this report.

Quality Control 

During the San Diego GAMA study, quality-control 

samples were collected at approximately 10 percent of the 

sampling sites. Quality-control samples are collected to assess 

the validity of ground-water data that will be used for interpretation, and to describe bias and variability in data associated 

with sample collection, processing, storage, transportation, 

and laboratory analysis. Three types of quality-control samples 

were collected in the field during the San Diego GAMA study: 

blanks, sequential replicates, and matrix spikes. 

Blanks

Four types of blanks were collected: trip, equipment, 

field, and source-solution. 

Trip blanks are collected to determine if shipping, handling, and intermittent storage of sample containers produces 

contamination (bias) with respect to VOCs. Equipment blanks 

are used to determine if the fittings and tubing used to collect 

ground-water samples are introducing contamination. Field 

blanks are collected to determine if procedures used during 

sample collection and laboratory analysis introduce contamination, as well as to determine if the decontamination procedures used to clean sampling equipment are effective. Source 

solution blanks are collected to verify that the water used for 

field blanks has no detectable concentrations of VOCs and 

waste-water indicator compounds. Source solution blanks are 

only collected for VOCs and waste-water indicator compounds 

because these chemicals are volatile and ubiquitous, and 

therefore can contaminate blank water used for quality-control 

samples.

 All blanks were processed using Nitrogen-Purged Universal blank water that is certified for use in the collection of 

blanks for VOCs, pesticides, waste-water and pharmaceutical 

compounds, low-level nutrients, dissolved organic carbon, 

major ions, and trace elements. The trip blank consisted of 

blank water in a sealed sample vial that was kept with the 

other sample vials from the start of the field activities through 

laboratory analysis. The equipment blank was collected at the 

USGS San Diego laboratory using the field sampling equipment, and immediately shipped to the NWQL for analysis. 

Field blanks were collected at the sampling site. Depending on 

the schedule (expanded, basic-plus, basic) employed at a particular sampling site, blank water was either pumped, using a 

diaphragm pump equipped with a Teflon diaphragm, or poured 

through the sampling equipment (fittings and tubing) used to 

collect ground water. Blank samples were then processed and 

transported utilizing the same methods used for the collection 

of ground-water samples. Source-solution blanks also were 

collected at the sampling site by pouring blank water directly 

into sample containers that were then stored, shipped, and 

analyzed in the same manner as the ground-water samples. 

Contamination may have been introduced into groundwater samples during collection, processing and transport if 

the following criteria are met: (1) a constituent is detected in 

trip, equipment, or field blanks, (2) the constituent is detected 

in ground-water samples, and (3) the minimum concentration 

detected in ground-water samples is less than the maximum 

concentration detected in field blanks. If a constituent was 

detected in a trip, equipment, or field blank, then the concentration detected in the blank was compared with the concentration detected in the associated source solution blank. If the 

source solution was identified as the origin of the detection in 

the blank, then contamination of ground-water samples by the 

constituent was not of concern. 

Field blank detections that could not be attributed to the 

source solution were compared to detections in associated 

ground-water samples, and evaluated with respect to criterion 

3 above. Associated ground-water samples are defined here 

as any sample collected on the same day as the field blank. 

If the field blank was collected at a well that was sampled on 

an expanded schedule, then the detection in the field blank 

was compared with detections in the ground-water sample 

collected immediately before the field blank. A detection 

of a constituent in the field blank that is also detected in the 

ground-water sample collected immediately before the field 

blank indicates possible carry-over contamination. Carry-over 

contamination occurs when a constituent is introduced into 

a sample from the sampling equipment, in spite of the cleaning of sample tubing and fittings. If carry-over contamination 

was identified as the cause of the detection in the field blank, 

subsequent ground-water samples and field blanks also were 

evaluated for evidence of carry-over contamination. Carryover contamination was not considered to be a problem if the 

constituent in question was not detected in the ground-water 

samples collected prior and subsequent to the field blank. 

Wells sampled on basic and basic-plus schedules do not use 

sample tubing and fittings that have been used previously to 

collect ground-water samples, and thus field blanks collected 

at these sites are not evaluated with respect to carry-over 

contamination. 

Methods 15
Ground-water samples that were determined to have 

a detection of one or more constituents resulting from contamination were censored, and consequently not used in the 

analysis of ground-water quality. The threshold for censoring 

data was determined by summing the blank concentration and 

the LT-MDL, or MDL, for the constituent in question. For 

example, if toluene was detected in a field blank at a concentration of 0.02 μg/L, and the LT-MDL for toluene is 0.02 μg/L, 

then the concentration of toluene in the associated groundwater sample would have to be greater than, or equal to, 

0.04 μg/L in order to be included in ground-water quality 

analyses. This method of censoring is based on the assumption 

that the amount of contamination in the field blank and the 

associated ground-water sample are comparable. Therefore, 

detections in ground-water samples that are not censored will 

have at least a concentration equal to the LT-MDL, or MDL, 

where the risk of reporting a false positive reading when 

a constituent concentration is greater than, or equal to, the 

LT-MDL, or MDL, is 1 percent or less (Childress and others, 

1999). If a constituent was detected in multiple blanks (trip, 

equipment, or field), and the detections could not be attributed 

to the source solution or to carry-over contamination, then any 

ground-water sample that had a detection of the constituent in 

question was censored at the appropriate threshold.

Replicates 

Sequential replicate samples assess variability in the 

processing and analyses of inorganic and organic constituents. 

Relative standard deviation (RSD) was used in determining the 

variability between replicate pairs. The RSD is defined as 100 

times the standard deviation divided by the mean concentration for each replicate pair of samples. If one value in a sample 

pair was reported as a non-detection and the other value was 

reported as an estimate below the LRL or MRL, the RSD was 

set to zero because the values are analytically identical. If one 

value in a sample pair was reported as a non-detection and 

the other value was greater than the LRL or MRL, then the 

non-detection value was set equal to one-quarter of the LRL, 

and the RSD was calculated (Childress and others, 1999). 

RSD values less than 20 percent are considered acceptable in 

this study. High RSD values for a constituent likely indicate 

analytical uncertainty at low concentrations, particularly for 

concentrations within an order of magnitude of LT-MDL or 

MDL. 

Matrix Spikes

Matrix spikes are used to evaluate bias and variability of 

analytical results related to matrix interferences. Matrix spike 

samples are prepared by adding solutions containing known 

amounts of organic compounds to replicate ground-water 

samples. The known compounds added in matrix spikes are 

the same as those being analyzed in the method. This enables 

an analysis of matrix interferences on a compound-by-compound basis. Matrix spikes in the San Diego GAMA study 

were always done by the laboratory performing the analysis. 

Compounds with low recoveries are of potential concern if 

environmental concentrations are close to the MCLs; a nonexceedance of an MCL could be falsely indicated. Conversely, 

compounds with high recoveries are of potential concern 

if the environmental concentrations exceed MCLs, since a 

high recovery could falsely indicate an exceedance of MCL. 

Recoveries between 70 to 130 percent for matrix spikes were 

considered acceptable in this study.

Surrogate Compounds 

In addition to matrix spikes, surrogate compounds were 

added to all ground-water and quality-control samples that 

were analyzed for VOCs, gasoline oxygenates, pesticides, 

waste-water, and pharmaceutical compounds. Prior to analysis, 

each sample is spiked with surrogate compounds at the laboratory. Surrogate compounds are not normally found in the environment and are used to identify potential problems associated 

with laboratory analyses. Potential problems include matrix 

interferences (such as high levels of dissolved organic carbon) 

that produce a positive bias, and incomplete laboratory recovery (possibly due to improper maintenance and calibration of 

analytical equipment) that produces a negative bias. Surrogate 

compounds are used to identify general problems that may 

arise during sample analysis that can affect the analysis results 

for all compounds, whereas matrix spikes are used to indicate 

problems with specific compound analysis. A 70- to 130-percent recovery of surrogates is generally considered acceptable, except for pharmaceuticals where the acceptable range 

of recoveries is 75 to 115 percent; values outside these ranges 

indicate possible problems with the processing and analysis of 

samples (Connor and others, 1998). 

16 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Results

Quality-Control Samples

Detections in Blanks

A summary of constituent detections in trip, equipment, 

and field blanks is given in table 5. No targeted constituents 

were detected in the trip blank. Three VOCs (trichloromethane, toluene, and acetone) and NDMA were detected in one 

of the five field blanks. The field blank detections were not 

of concern because these constituents were also detected 

in the associated source-solution blanks. Pesticides, nutrients, and dissolved organic carbon were not detected in any 

blanks. Silica and calcium were detected in two of two field 

blanks, and sodium was detected in one of two field blanks. 

Concentrations detected in the field blanks were at least two 

orders of magnitude below concentrations detected in groundwater samples; therefore, no data were censored. Copper 

was the only constituent detected in the equipment blank; it 

was detected at a concentration of 0.9 μg/L. Copper was also 

detected in one of two field blanks at a concentration of 

1.2 μg/L. Because of these detections, all copper concentrations in ground-water samples that are below 1.4 μg/L are censored. In addition to copper, vanadium and zinc were detected 

in one of two field blanks at a concentration of 0.8 and 

0.3 μg/L, respectively. Because of these field blank detections, 

three detections of vanadium and one detection of zinc were 

censored in ground-water samples. 

Phenol, a waste-water indicator compound, has been a 

persistent contaminant found in field blanks collected across 

the nation (Jim Kingsbury, Hydrologist, U.S. Geological 

Survey, written commun., 2004). A review of quality-control 

data collected as part of the NAWQA Source Water Quality 

Assessment showed that phenol was present in 66 percent of 

field blanks nationwide. Because of this ongoing problem with 

phenol contamination, all phenol detections in this study were 

subjected to censoring. The maximum concentration detected 

in field blanks for the San Diego GAMA was 0.2 μg/L. Therefore, all phenol detections less than 0.4 μg/L were censored.

Variability in Replicate Samples

The majority of replicate pairs collected during the San 

Diego GAMA study had RSDs of less than 10 percent 

(table 6A-E). Fifteen of nearly 1,500 replicate pairs, representing nine compounds and two measurements of gross radioactivity in water, exceeded the acceptable RSD set for this study 

of 20 percent. Perchlorate had one replicate pair that slightly 

exceeded the acceptable limit set for this study with a RSD 

of 21 percent. Nutrients, DOC, and major ions did not have 

any replicate pairs with an RSD greater than 7 percent. Three 

trace elements had replicate pairs with high RSDs (table 6D). 

Two chromium replicate pairs had RSDs of 47 and 57 percent; 

hexavalent chromium had two replicate pairs with RSDs of 

47 and 85 percent, and vanadium had one replicate pair with a 

RSD of 31 percent. Constituents in these replicate pairs were 

detected at concentrations close to, or below, their LT-MDLs 

or MDLs. 

Two measures of gross radioactivity in water, and two 

radioisotopes, had replicate-pair RSDs that were higher than 

the acceptable limits set for this study (table 6E). Two replicate pairs for 30-day counts of alpha radioactivity had RSDs 

of 66 and 60 percent, and one replicate pair for a 

72-hour count of beta radioactivity had a slightly high RSD of 

21 percent. The activities detected in these replicate pairs were 

at, or below, MDLs except for the replicate pair of 72-hour 

beta radioactivity that had activities approximately two and 

four times higher than the MDL. Radium-228 had a replicate 

pair RSDs of 37 and 26 percent, and one tritium replicate pair 

had a RSD of 91 percent; detections in these replicates were at 

activities that were at, or below, MDLs.

Matrix Spike Recoveries

A summary of matrix spike recoveries for the San Diego 

GAMA study is shown in table 7A-C. Nineteen VOCs had at 

least one matrix spike recovery greater than 130 percent 

(table 7A). Four of the 19 VOCs were detected in groundwater samples; chloroform was detected in 18 ground-water 

samples, and benzene, chloromethane, and 1,2-dichloroethane 

were each detected in one ground-water sample. All detections 

in ground-water samples were at concentrations well below 

MCLs. Styrene was the only VOC that had a matrix spike 

recovery below 70 percent; it was not detected in any groundwater samples.

Sixteen pesticides had at least one matrix spike recovery 

greater than 130 percent (table 7B). Two of the 16 pesticides 

were detected in ground-water samples; imazethapyr was 

detected in one ground-water sample and hydroxyatrazine 

was detected in two ground-water samples. Neither compound 

has a drinking-water standard. Sixty-six pesticides had matrix 

spike recoveries below 70 percent (table 7B). Of the 66 pesticides, the following 13 were detected in ground-water samples: 3,4-dichloroaniline, acetochlor, deethylatrazine, deisopropyl atrazine, desulfinyl fipronil, hexazinone, metalaxyl, 

metolachlor, myclobutanil, prometon, prometryn, simazine, 

and tebuthiuron. Of the pesticides with a low matrix spike 

recovery, simazine is the only one that is regulated, with an 

MCL of 4 μg/L. Concentrations of simazine in ground-water 

samples did not exceed 0.03 μg/L except in one case where a 

concentration of 0.2 μg/L was detected. 

Results 17
One waste-water indicator compound, caffeine, had a 

matrix spike recovery greater than 130 percent (table 7C). 

Caffeine was detected in one ground-water sample, and does 

not have an MCL. Twelve waste-water indicator compounds 

had at least one matrix spike recovery below 70 percent. Of 

the twelve compounds, only D-limonene was detected; it was 

detected in one ground-water sample at concentrations below 

the LT-MDL. D-limonene does not have an MCL.

Surrogate Compound Recoveries

A summary of surrogate compound recoveries for 

ground-water and quality-control samples is given in table 8. 

Four ground-water samples analyzed for VOCs had recoveries 

of the surrogate 1,2-dichloroethane-d4 that were higher than 

the acceptable limit of 130 percent; recoveries ranged from 

132 to 142 percent. Two of the four ground-water samples 

with high surrogate recoveries had VOC detections. The wells 

SDHDRK-05 and SDALLV-11 had one and six VOC detections, respectively. All detections in these wells were at least 

an order of magnitude below MCLs, except for a MTBE 

detection in SDALLV-11 which was detected at 28.3 μg/L; the 

MCL for MTBE is 13 μg/L.

Analyses for gasoline oxygenates in two field blanks and 

two source solution blanks had recoveries of the surrogate 

isobutyl alcohol-d6 that were below the acceptable limit of 

70 percent; recoveries ranged from 60 to 64 percent. Each 

blank had a detection of acetone; however, acetone was not 

detected in any ground-water samples. VOC analysis for one 

replicate had a recovery of 144 percent for the surrogate 1,2-

dichloroethane-d4. No VOCs were detected in the replicate.

All surrogate recoveries for pesticide and pesticide degradates in ground-water and quality-control samples analyzed 

by analytical schedule 2003 were within acceptable limits. 

Twelve surrogate recoveries were outside the acceptable limits 

for nine ground-water samples analyzed for pesticides and 

pesticide degradates by analytical schedule 2060. The surrogate caffeine-13C had nine recoveries that ranged from 131 

to 141 percent, the surrogate barban had recoveries of 140 

and 150 percent, and the surrogate 2,4,5-T had a recovery 

of 62 percent. A total of five pesticides were detected in two 

ground-water samples that had high surrogate recoveries. The 

well SDTEM-01 had one detection, and the well SDTEM-06 

had four detections. None of the pesticides detected in either 

sample has a drinking-water standard. 

One field blank sample had a recovery of 145 percent for 

the surrogate caffeine-13C. No pesticide or pesticide degradates were detected in this sample. One replicate had recoveries of 138 and 152 percent for the surrogates barban and 

caffeine-13C, respectively. No pesticides or pesticide degradates were detected in this sample. A matrix spike sample had 

recoveries of 152 and 135 percent for the surrogates barban 

and caffeine-13C, respectively. Eighteen compounds in the 

matrix spike sample had recoveries of greater than 

130 percent.

Forty-three ground-water samples analyzed for wastewater indicator compounds had surrogate recoveries outside 

acceptable limits. Ranges for surrogate recoveries were 

bisphenol A-d3 from 0 to 150 percent; caffeine-13C from 83 

to 152 percent; decafluorobiphenyl from 35 to 86 percent; and 

fluoranthene-d10 from 66 to 154 percent. Twenty wells had a 

total of 23 waste-water indicator compound detections; all 20 

wells had surrogate recoveries outside the acceptable limits. 

The majority (70 percent) of surrogate recoveries were below 

the acceptable limit of 70 percent. None of the waste-water 

indicator compounds has a drinking-water standard.

Based on surrogate recoveries, results for some wastewater indicator compound analyses of quality-control samples 

may have been biased due to problems with sample processing and/or analytical methods. One field blank had surrogate 

recoveries of 150 percent for caffeine-13C and 146 percent for 

fluoranthene-d10, and one source-solution blank had surrogate 

recoveries of 146 percent for caffeine-13C and 145 percent for 

fluoranthene-d10. No waste-water indicator compounds were 

detected in either blank sample. Three replicates had surrogate 

recoveries outside the acceptable limits. Bisphenol A-d3 was 

recovered in two replicates at 44 and 45 percent, and decafluorobiphenyl was recovered in one replicate at 58 percent. 

Waste-water indicator compounds were not detected in either 

replicate. One matrix spike had a recovery of bisphenol A-d3 

at 134 percent, and a recovery of decafluorobiphenyl at 54 percent. Ten compounds in the matrix spike had recoveries of less 

than 70 percent. The low surrogate recovery for decafluorobiphenyl indicates that results for this sample may be negatively 

biased, which may explain the low recoveries observed in the 

matrix spike.

Ground-Water Quality

The San Diego GAMA ground-water quality data 

presented in this report are available in the USGS National 

Water Information System database (NWIS), except for the 

following constituents: tritium and noble gases analyzed at 

LLNL; chromium, arsenic, and iron speciation analyzed at the 

USGS national research program (NRP) laboratory in Boulder, 

Colorado; and perchlorate, NDMA, and 1,4-dioxane analyzed 

at Montgomery Watson and Harza laboratory. 

18 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 9 shows the general water-quality indicators determined in the field; tables 10-20 show the results of analyses 

of ground-water samples organized by constituent class and 

microbial constituents. For simplicity, tables presenting the 

results of analyses are summarized for the following constituent classes: VOCs, gasoline oxygenates, pesticides and pesticide degradates, and waste-water indicators. In these tables, 

only constituents that were detected, and wells that had at least 

a single constituent detection, are shown. Each table shows 

the number of times a constituent was detected, the frequency 

at which the constituent was detected, and the number of constituents detected per well. Additionally, VOCs and gasoline 

oxygenates are combined into one table. Concentrations, or 

activities, that exceed MCLs are highlighted in the tables by 

bold font with an asterisk; exceedances of SMCLs are highlighted by bold font; and exceedances of DLRs are highlighted 

by bold, italicized font. 

Detections in the Temecula Valley study area are divided 

into two categories, detections in non-flow path wells, which 

are referred to simply as Temecula Valley study area wells, 

and detections in flow path wells. Flow path wells are not 

included in comparisons of detections between study areas 

because the addition of flow-path wells introduces possible 

spatial bias in the Temecula Valley study area; the bias could 

arise from sampling additional wells in a relatively small area. 

The chemical and microbial data presented in this report 

are meant to characterize the quality of the untreated groundwater resources in the San Diego GAMA study unit and not 

the treated drinking water delivered to consumers by water 

purveyors. The chemical and microbial composition of treated 

drinking water may differ from untreated ground water in that 

treated drinking water may be subjected to disinfection, filtration, mixing with other waters, and exposure to the atmosphere 

prior to being delivered to the consumer.

VOCs and Gasoline Oxygenates

VOC and gasoline oxygenate samples were collected 

at all 58 wells sampled in the San Diego GAMA study unit. 

Twenty-eight wells had at least a single detection of a VOC or 

gasoline oxygenate (table 10). VOCs and gasoline oxygenates 

were detected in 11 of 17 wells in the Alluvial Basins study 

area, 7 of 14 wells in the Temecula Valley study area, 4 of 

13 wells in the Hard Rock study area, and 1 of 9 wells in the 

Warner Valley study area. VOCs and gasoline oxygenates were 

detected in 5 of 5 Temecula Valley study area flow path wells.

Eighteen of the 88 VOCs and gasoline oxygenates analyzed for were detected in the ground-water samples. Trihalomethanes were the most frequently detected class of VOCs; 

they were detected in 18 of 58 wells. The next most frequently 

detected class of VOCs were solvents, detected in 12 of 

58 wells, followed by VOCs found in gasoline, 9 of 58 wells, 

and VOCs used in manufacturing (organic synthesis), 3 of 

58 wells. Chloroform was the most frequently detected constituent, detected in 18 of 58 wells, followed by bromodichloromethane, 8 of 58 wells, and methyl tert-butyl ether (MTBE), 

7 of 58 wells. Three VOCs were detected at concentrations 

greater than the MCL (table 10). Tetrachloroethylene (PCE) 

and trichloroethylene (TCE) were both detected in SDHDRK01 at concentrations of 9.75 mg/L and 7.27 mg/L, respectively. 

The MCL for both of these constituents is 5 mg/L. MTBE was 

detected in SDALLV-11 at a concentration of 28.3 mg/L; the 

MCL for MTBE is 13 mg/L.

Pesticides and Pesticide Degradates

Pesticide and pesticide degradate samples determined 

by analytical schedule 2003 were collected at all 58 wells sampled for the San Diego GAMA study unit, and pesticides and 

pesticide degradate samples determined by analytical schedule 

2060 were collected at 24 wells. Because pesticide analytical 

schedule 2060 was not sampled at a uniform rate across the 

four study areas, constituents detected by this method will not 

be included when calculating the detection frequency of pesticides and pesticide degradates in the individual study areas. 

Thirty-three of 58 wells sampled had at least a single detection 

of a pesticide or pesticide degradate (table 11). Pesticides and 

pesticide degradates were detected in 9 of 14 wells in the Temecula Valley study area, 10 of 17 wells in the Alluvial Basins 

study area, 7 of 13 wells in the Hard Rock study area, and 

3 of 9 wells in the Warner Valley study area. Pesticides and 

pesticide degradates were detected in 4 of 5 flow-path wells in 

the Temecula Valley study area.

Twenty-one of the 122 pesticides and pesticide degradates analyzed for were detected in ground-water samples. 

Herbicides were the most frequently detected class of pesticides; they were detected in 31 of 58 wells. Pesticide degradates were detected in 19 of 58 wells, and fungicides were 

detected in 4 of 58 wells. Simazine was the most frequently 

detected pesticide, detected in 27 of 58 wells. The degradation product deethylatrazine was the second most frequently 

detected constituent, identified in 14 of 58 wells, and the pesticides prometon and atrazine were detected in 10 and 9 wells, 

respectively. None of the pesticide concentrations detected 

exceeded MCLs.

Results 19
Waste-Water Indicator Compounds

Waste-water indicator compounds were collected at 

50 wells, but three samples were ruined before analysis, 

and consequently no waste-water analyses are available for 

SDWARN-08, SDTEM-10, and SDHDRK-11. Eight different 

waste-water indicator compounds were detected in samples. 

Twenty of 47 wells sampled had at least a single detection of 

a waste-water indicator compound (table 12). These constituents were detected in 9 of 17 wells in the Alluvial Basins 

study area, 6 of 12 wells in the Hard Rock study area, 3 of 8 

wells in the Warner Valley study area, and 2 of 6 wells in the 

Temecula Valley study area. Waste-water indicator compounds 

were detected in 1 of 5 flow-path wells in the Temecula Valley 

study area. Phenol was the most frequently detected constituent, being identified in 14 of 47 wells. However, given the 

fact that phenol has been a persistent contaminant found in 

field blanks, and that 10 of 14 detections in this study were 

at, or within, 0.1 μg/L of the censoring threshold, phenol data 

should be used with caution when interpreting ground-water 

quality in the San Diego GAMA study unit. None of the 

waste-water indicator compounds detected in this study has a 

drinking-water standard.

Perchlorate, NDMA, and 1,4-dioxane

Perchlorate and NDMA were collected at 50 wells, and 

1,4-dioxane at 24 wells (table 13). Of the 50 wells in which 

perchlorate was measured, 14 of them had detections. Perchlorate was detected in 4 of 7 wells in the Temecula Valley 

study area, 2 of 9 wells in the Warner Valley study area, 3 of 

17 wells in the Alluvial Basins study area, and 2 of 13 wells 

in the Hard Rock study area. Perchlorate was also detected 

in 3 of 4 flow-path wells in the Temecula Valley study area. 

Perchlorate was detected in SDALLV-05 at a concentration of 

4.2 μg/L, which is above the DLR concentration of 4 μg/L. 

NDMA and 1,4-dioxane were not detected in any samples.

Nutrients and Dissolved Organic Carbon

Nutrients and DOC samples were collected at 24 wells 

(table 14). Nitrate was detected in 17 of 24 wells, whereas 

nitrite was detected in only 2 wells. Concentrations of nitrate 

as N did not exceed the MCL of 10 mg/L; values range from 

less than 0.1 mg/L to 9.14 mg/L. Nitrite was detected in two 

wells at estimated concentrations of 0.006 mg/L and 0.028 

mg/L. Neither of these concentrations is close to the nitrite 

MCL of 1 mg/L. Ammonia was detected in 6 of 24 wells at 

concentrations less than or equal to 0.18 mg/L. Dissolved 

phosphorus and DOC were both detected in all but two wells. 

Major Ions and Total Dissolved Solids

Major ion and total dissolved solids (TDS) samples were 

collected at 24 wells (table 15). Nine of 24 wells had TDS 

concentrations that exceeded the recommended SMCL of 

500 mg/L, and 3 of 24 wells had TDS concentrations that 

exceeded the upper limit of the SMCL of 1,000 mg/L. Concentrations of TDS that exceeded SMCLs ranged from 508 to 

1,800 mg/L. All six wells in the Alluvial Basins study area, 

in which TDS was measured, had concentrations above the 

SMCL; four wells had concentrations greater 500 mg/L, and 

two wells had concentrations above 1,000 mg/L. Four of seven 

wells sampled for TDS in the Temecula Valley study area had 

concentrations greater than 500 mg/L, one of four wells in the 

Hard Rock study area had a TDS concentration greater than 

the upper-limit SMCL (1,198 mg/L), and none of the three 

wells sampled for TDS in the Warner Valley had concentrations greater than 325 mg/L. One of four flow-path wells 

in the Temecula Valley study area had a TDS concentration 

greater than 500 mg/L. However, two of the flow path wells 

had TDS concentrations of 478 and 494 mg/L.

Two wells had exceedances of the chloride SMCL and 

three wells had exceedances of the sulfate SMCL. SDALLV06, which had a TDS concentration of 1,800 mg/L, had a 

chloride concentration of 540 mg/L and sulfate concentration 

of 421 mg/L. This well exceeded the upper limit chloride 

SMCL of 500 mg/L and the recommended sulfate SMCL of 

250 mg/L. SDALLV-03, which had a TDS concentration of 

1,240 mg/L, had a chloride concentration of 472 mg/L, and 

SDALLV-01 and SDHDRK-05 had sulfate concentrations of 

271 and 320 mg/L, respectively.

20 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Trace Elements

Trace element samples were collected at 24 wells 

(table 16). Of the 25 trace elements measured, 11 have a 

MCL, six have a SMCL, and three are listed as UCMR constituents, and therefore have a DLR. Beryllium and mercury 

were the only trace elements not detected in any sample; the 

LRL for these constituents are 0.01 and 0.06 mg/L, respectively. Arsenic was detected in all 24 wells at concentrations 

ranging from less than 0.5 mg/L to 7.8 mg/L. These concentrations are below the current arsenic MCL of 50 mg/L, as well as 

the proposed MCL of 10 μg/L that is scheduled to take effect 

in 2006. Uranium, barium, and nickel also were detected in all 

24 wells sampled. Uranium concentrations range from 0.06 

mg/L to 17.8 mg/L. When converted from mass units to activities using the standard conversion factor of 0.67 pCi/mg, all 

uranium activities are below the DHS MCL of 20 pCi/L (U.S. 

Environmental Protection Agency, 2004). Barium concentrations range from 2 mg/L to 147 mg/L, and nickel concentrations range from 0.14 mg/L to 3.44 mg/L. Concentrations for 

these constituents are well below the MCLs for both barium 

(1,000 mg/L) and nickel (100 mg/L). Selenium has a MCL of 

50 mg/L, and was detected in all but one well. Detections of 

selenium are at concentrations below 3 mg/L, except for the 

sample collected at SDALLV-01, where the concentration is 

30.9 mg/L. 

Chromium analysis of samples was done at two different 

laboratories. Total chromium was analyzed in 24 samples at 

the NWQL (table 16), and in 50 samples at the Boulder NRP 

laboratory (table 17). The NRP laboratory method of chromium analysis is more sensitive than the method used by the 

NWQL. In addition, the NRP laboratory analyzes for hexavalent chromium, which is classified as an UCMR constituent. 

Total chromium, as determined at the NRP laboratory, was 

detected in 44 of 50 wells. Concentrations range from 

0.1 mg/L to 5.7 mg/L, with the majority of samples having concentrations less then 2 mg/L. The MCL for total chromium is 

50 μg/L. Hexavalent chromium was detected in 36 of 50 wells. 

Much like total chromium, hexavalent chromium concentrations range from 0.1 mg/L to 5.6 mg/L, with the majority of 

samples having concentrations less then 2 mg/L. Seven wells 

with hexavalent chromium detections have concentrations 

that exceed the DLR of 1 mg/L; four of these wells are in the 

Temecula Valley study area.

Iron was detected in two wells at concentrations above 

its SMCL of 300 mg/L (table 16). The wells SDALLV-06 and 

SDALLV-13 had iron concentrations of 2,120 mg/L and 

578 mg/L, respectively. Manganese was detected in four wells 

at concentrations that exceed its SMCL of 50 μg/L. The wells 

SDALLV-03, SDALLV-06, SDALLV-13, and SDHDRK-06 

had manganese concentrations of 169 mg/L, 492 mg/L, 

362 mg/L, and 178 mg/L, respectively. 

Boron was detected in 23 of the 24 wells sampled. Of 

those 23 detections, 15 exceed the boron DLR of 100 mg/L. 

Boron concentrations exceed the DLR most frequently in 

the Alluvial Basins study area (5 of 6 wells), followed by the 

Temecula Valley study area (5 of 7 wells), the Warner Valley 

study area (1 of 3 wells), and the Hard Rock study area (1 of 

4 wells). Boron concentrations are also greater than the DLR 

in three of four Temecula Valley study area flow-path wells. 

Vanadium was detected in 20 of the 24 wells sampled. Of 

those 20 detections, 14 have concentrations that exceed the 

vanadium DLR of 3 mg/L. Vanadium concentrations exceed 

the DLR most frequently in the Warner Valley study area (3 of 

3 wells), followed by the Temecula Valley study area (5 of 7 

wells), the Hard Rock study area (2 of 4 wells), and the Alluvial Basins study area (1 of 6 wells). Vanadium concentrations 

are also greater than the DLR in three of four Temecula Valley 

study area flow-path wells.

Isotopes, Radioactivity, and Noble Gases

Isotope activities, stable isotopes, and gross alpha/beta 

radioactivity were determined in ground-water samples collected for the San Diego GAMA study unit (tables 18 and 

19). Stable isotopes of water, tritium (using two methods 

of analysis), and noble gases were collected at all 58 wells, 

whereas radium-226, radium-228, radon-222, alpha radioactivity (72-hour and 30-day count), beta radioactivity (72-hour and 

30-day count), and carbon isotopes were collected at 24 wells. 

Tritium samples, determined by the helium in-growth method, 

and noble gas samples were collected at all 58 wells 

(table 19). These samples were analyzed at LLNL, and the 

results can be used to help determine the chronology and 

source of ground-water recharge.

Tritium was detected in most samples (table 19). The 

highest activity detected in any sample was 23.7 pCi/L; the 

MCL for tritium is 20,000 pCi/L. Radium-226 was detected 

in all samples, but concentrations never exceeded 0.41 pCi/L. 

Radium-228 was detected in all but four samples. Detections 

were so low that quantification is not possible except for one 

sample where it was detected at an activity of 2 pCi/L. No 

wells exceeded the combined radium-226 and radium-228 

MCL of 5 pCi/L. Alpha radioactivity in samples ranged from 

below quantification limits to 9 pCi/L for both 72-hour and 

30-day counts, which does not exceed the alpha radioactivity 

MCL of 15 pCi/L. Beta radioactivity ranges from below quantification limits to 7 pCi/L for 72-hour counts, and from 

2 pCi/L to 11 pCi/L in 30-day counts. The MCL for beta 

radioactivity is 50 pCi/L. 

Results 21
Radon-222 was detected in every ground-water sample 

in which it was analyzed, with activities ranging from 180 to 

4,820 pCi/L. In 15 of 24 wells, radon-222 activities exceed 

the proposed MCL of 300 pCi/L (table 18), and one sample 

exceeds the proposed alternate maximum contaminant level 

(AMCL) of 4,000 pCi/L (U.S. Environmental Protection, 

Agency, 2000b). Radon-222 exceeded the proposed MCL 

in three of three wells in the Warner Valley study area, four 

of four wells in the Hard Rock study area, three of six wells 

in the Alluvial Basins study area, and two of seven wells in 

the Temecula Valley study area. In addition, radon-222 was 

measured at activities greater than 300 pCi/L in three of four 

Temecula Valley study area flow-path wells.

Microbial Constituents

Microbial constituents were analyzed for in 24 groundwater samples collected for the San Diego GAMA study 

(table 20). The following microbial constituents were determined: total coliform and Escherichia coliform, and the 

viruses F-specific coliphage and somatic coliphage. Total 

coliform and Escherichia coliform were not detected in 

any samples. F-specific coliphage was detected in one well, 

SDALLV-13, and somatic coliphage was detected in two 

wells, SDTEM-13 and SDWARN-04. Coliphage results are 

reported as being either present or absent.

Summary

The GAMA program provides a comprehensive statewide assessment of ground-water quality in areas of California where public-supply wells provide an important source 

of drinking water. The San Diego GAMA study unit is the 

first region where an assessment of ground-water quality 

was implemented under the GAMA program. The San Diego 

GAMA study unit covers the entire San Diego Drainages 

hydrogeologic province, and consists of four distinct hydrogeologic study areas: the Temecula Valley study area, the 

Warner Valley study area, the Alluvial Basins study area, and 

the Hard Rock study area. A total of 58 ground-water samples 

were collected from public-supply wells in the San Diego 

GAMA study unit: 19 wells were sampled in the Temecula 

Valley study area, 9 wells in the Warner Valley study area, 17 

wells in the Alluvial Basins study area, and 13 wells in the 

Hard Rock study area. 

This report presents the results of sample analyses for 

over 350 chemical and microbial constituents, and water-quality indicators collected from the 58 public supply wells from 

May to July 2004. The results of sample analyses are presented as detection frequencies for individual constituents, and 

classes of constituents, for the entire San Diego GAMA study 

unit and for the individual study areas. In addition, results of 

sample analyses are compared to MCLs, SMCLs, and DLRs. 

The chemical and microbial data presented in this report are 

meant to characterize the quality of the untreated ground-water 

resources in this study unit and not the treated drinking water 

delivered to consumers by water purveyors. The chemical and 

microbial composition of treated drinking water may differ 

significantly from untreated ground water in that treated drinking water may be subjected to disinfection, filtration, mixing 

with other waters, and exposure to the atmosphere prior to 

being delivered to the consumer.

 Eighteen of the 88 VOCs and gasoline oxygenates 

analyzed were detected in samples. VOCs and gasoline 

oxygenates were detected in 28 of 58 wells sampled. These 

constituents were most frequently detected in wells located 

in the Alluvial Basins study area (11 of 17 wells), and least 

frequently in the Warner Valley study area (1 of 9 wells). 

Trihalomethanes were the most frequently detected classes of 

constituents, being identified in 18 of 58 wells. Chloroform 

was the most frequently detected constituent (18 of 58 wells). 

MTBE was also relatively frequently detected; it was identified in 7 of 58 wells. Three constituents had detections that 

exceeded MCLs (table 10). PCE and TCE were detected in 

SDHDRK-01 at concentrations of 9.75 μg/L and 7.27 μg/L, 

respectively. The MCL for these constituents is 5 ug/L. MTBE 

was detected in well SDALLV-11 at a concentration of 28.3 

μg/L, which exceeds the MCL of 13 μg/L. 

Twenty-one of the 122 pesticides and pesticide degradates analyzed were detected in this study. Pesticides and 

pesticide degradates were detected in 33 of 58 wells sampled. 

These constituents were detected most frequently in the Temecula Valley study area (9 of 14 wells), and least frequently in 

the Warner Valley study area (3 of 9 wells). Herbicides were 

the class of constituents most frequently detected throughout 

the study unit (31 of 58 wells), and simazine, a herbicide, was 

the most frequently detected compound (27 of 58 wells). None 

of the concentrations of pesticides and pesticide degradates 

exceeded MCLs.

Eight waste-water indicator compounds were identified in samples. Twenty of 47 wells sampled for waste-water 

indicator compounds had at least a single detection. These 

constituents were detected most frequently in the Alluvial 

Basins study area (9 of 17 wells), and least frequently in the 

Temecula Valley study area (2 of 6 wells). Phenol was the 

most frequently detected constituent; it was found in 14 of 47 

wells. However, phenol has been a persistent contaminant in 

field blanks, and therefore phenol results should be used with 

caution when interpreting water quality in this study. Perchlorate was detected in 14 of 50 wells in the San Diego GAMA 

study unit. Perchlorate was detected in one well, SDALLV-05, 

at a concentration (4.2 μg/L) above the DLR.

22 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Nitrate was detected in 17 of the 24 wells that were 

sampled for nutrients. None of the nitrate concentrations in 

samples exceeded the MCL of 10 mg/L. Twelve of the 24 

wells sampled for major ions had TDS concentrations that 

exceeded the recommended SMCL of 500 mg/L, with three 

of these wells also exceeding the upper-limit SMCL of 1,000 

mg/L. All six wells in the Alluvial Basins study area, in 

which TDS was measured, had concentrations greater than 

the SMCL; four wells had concentrations greater than 500 

mg/L, and two wells had concentrations greater than 1,000 

mg/L. None of the wells measured for TDS in the Warner 

Valley study area had concentrations that exceeded SMCLs. 

Four wells with high TDS also had concentrations of chloride 

and sulfate that exceeded SMCLs. Well SDALLV-06 had a 

chloride concentration of 540 mg/L and a sulfate concentration 

of 421 mg/L, which exceeds the chloride upper limit SMCL of 

500 mg/L and the recommended sulfate SMCL of 250 mg/L. 

Well SDALLV-03 had a chloride concentration of 472 mg/L, 

and wells SDALLV-01 and SDHDRK-05 had sulfate concentrations of 271 and 320 mg/L, respectively.

Of the 25 trace elements analyzed in this study, only 

beryllium and mercury were not detected at the LRL of 

0.01 and 0.06 μg/L, respectively. Arsenic and uranium were 

detected in all 24 wells in which they were measured, but at 

concentrations below their respective MCLs. Additionally, 

arsenic concentrations did not exceed the 10 μg/L MCL that 

will replace the current MCL of 50 μg/L in 2006. Forty-four 

of 50 wells that were analyzed for chromium had detectable 

concentrations; all total chromium concentrations were below 

its MCL of 50 μg/L. Thirty-six of 50 wells had detectable 

amounts of hexavalent chromium; seven of these wells had 

concentrations that exceeded the hexavalent chromium DLR 

of 1 μg/L.

Iron concentrations exceeded the SMCL of 300 μg/L in 

two wells; SDALLV-06 and SDALLV-13 had iron concentrations of 2,120 μg/L and 578 μg/L, respectively. Manganese 

was detected in four wells at concentrations that exceeded 

the SMCL of 50 μg/L; wells SDALLV-03, SDALLV-06, 

SDALLV-13, and SDHDRK-06 had manganese concentrations 

of 169 μg/L, 492 μg/L, 362 μg/L, and 178 μg/L, respectively. 

Boron was detected in 23 of 24 wells; 14 of those detections 

exceeded the boron DLR of 100 μg/L; the DLR was most frequently exceeded in the Alluvial Basins study area, and least 

frequently detected in the Hard Rock study area. Vanadium 

was detected in 20 of 24 wells; 11 of those detections had 

concentrations that exceeded the vanadium DLR of 3 μg/L; 

the DLR was most frequently exceeded in the Warner Valley study area, and least frequently exceeded in the Alluvial 

Basins study area.

Tritium was detected in the majority of samples; activities were well below the MCL of 20,000 pCi/L. Radium-226 

and radium-228 was detected together in all but four samples; 

however, activities detected in samples were low. Activities 

of radium-228 were below quantification limits in all but 

one sample. No wells exceeded the combined radium-226 

and radium-228 MCL of 5 pCi/L. Alpha and beta radioactivity were detected in all but two samples; activities did not 

exceed the respective MCLs of 15 and 50 pCi/L. Radon-222 

was detected in every ground-water sample in which it was 

analyzed. Radon-222 activities in 62 percent of the samples 

exceeded the proposed MCL of 300 pCi/L, and one sample 

exceeded the proposed alternate maximum contaminant level 

(AMCL) of 4,000 pCi/L (table 18). Radon-222 activities 

exceeded the proposed MCL in all Warner Valley and Alluvial 

Basins study area wells in which it was measured.

 Total coliform and Escherichia coliform were not 

detected in any of the 24 samples analyzed for microbial 

constituents. F-specific coliphage was detected in one well, 

SDALLV-13, and somatic coliphage was detected in two 

wells, SDTEM-13 and SDWARN-04. Coliphage results are 

reported as the organism either being present or absent.

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References 25
U.S. Environmental Protection Agency, 2002a, Guidelines for 

establishing procedures for the analysis of pollutants: U.S. 

Code of Federal Regulations, Title 40, pt.136, revised as of 

July 2002.

U.S. Environmental Protection Agency, 2002b, Method 

1604—Total coliforms and Escherichia coli in water by 

membrane filtration using a simultaneous detection technique (MI medium): Washington D.C., EPA 821–R–02–

024, 14 p. 

U.S. Environmental Protection Agency, 2004, National 

primary drinking water regulations—analytical method 

for uranium: U.S. Code of Federal Regulations, Title 40, 

pt.141, revised as of June 2004, p. 31008–31013.

U.S. Geological Survey, 1998, National Field Manual for the 

collection of water quality data: U.S. Geological Survey 

Techniques of Water Resources Investigations, book 9, 

variously paged.

U.S. Geological Survey, 1999, National Field Manual for the 

collection of water quality data: U.S. Geological Survey 

Techniques of Water Resources Investigations, book 9, 

variously paged.

Weiss, R.F., 1968, Piggyback sampler for dissolved gas studies 

on sealed water samples: Deep Sea Research, v. 15, 

p. 721–735.

Zaugg, S.D., Smith, S.G., Schroeder, M.P., Barber, L.B., and 

Burkhardt, M.R., 2002, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory—

Determination of wastewater compounds by polystyrenedivinylbenzene solid-phase extraction and capillary-column 

gas chromatography/mass spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 01–4186, 

p. 37.

26 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Tables

Tables 27
Expanded schedule Basic-plus schedule Basic schedule

Water-quality indicators 

(pH, SC, DO, temperature, alkalinity)

Water-quality indicators 

(SC and temperature)

Water-quality indicators 

(SC and temperature)

Volatile organic compounds Volatile organic compounds Volatile organic compounds

Gasoline oxygenates Gasoline oxygenates Gasoline oxygenates

Pesticides Pesticides Pesticides

Polar pesticides and degradates Waste-water indicator compounds Stable isotopes of water

Waste-water indicator compounds Pharmaceuticals Tritium1

Pharmaceuticals Emerging contaminants (perchlorate and NDMA) Tritium and noble gases2

Emerging contaminants (perchlorate, Chromium speciation

 1,4-dioxane, and NDMA) Stable isotopes of water

Nutrients and dissolved organic carbon Tritium1

Major ions and trace elements Tritium and noble gases2

Chromium speciation

Arsenic and iron speciation

Stable isotopes of water

Carbon isotopes

Radium isotopes

Gross alpha/beta radiation

Radon-222

Tritium1

Tritium and noble gases2

Microbial constituents

1

Analyzed at the U.S. Geological Survey stable isotope and tritium lab, Menlo Park, California.

2

Analyzed at Lawrence Livermore National Laboratory, Livermore, California.

Table 1. Classes of chemical and microbial constituents and water-quality indicators collected for the expanded, basic-plus, and basic 

sampling schedules in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

[SC, specific conductance; DO, dissolved oxygen; NDMA, N-nitrosodimethylamine]

28 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 2A. Volatile organic compounds, primary use or source, Chemical Abstract Service (CAS) number, and laboratory reporting level 

(LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2020. 

[μg/L, micrograms per liter]

Compound Primary use/source CAS number LRL

(μg/L)

1,1,1,2-Tetrachloroethane Solvent 630-20-6 0.03

1,1,1-Trichloroethane (TCA) Solvent 71-55-6 0.032

1,1,2,2-Tetrachloroethane Solvent 79-34-5 0.16

1,1,2-Trichloroethane Solvent 79-00-5 0.064

1,1,2-Trichlorotrifluoroethane (CFC-113) Refrigerant 76-13-1 0.038

1,1-Dichloroethane Solvent 75-34-3 0.035

1,1-Dichloroethylene Organic synthesis 75-35-4 0.024

1,1-Dichloropropene Organic synthesis 563-58-6 0.026

1,2,3,4-Tetramethylbenzene Hydrocarbon 488-23-3 0.14

1,2,3,5-Tetramethylbenzene (isodurene) Hydrocarbon 527-53-7 0.14

1,2,3-Trichlorobenzene Organic synthesis 87-61-6 0.27

1,2,3-Trichloropropane Solvent 96-18-4 0.18

1,2,3-Trimethylbenzene Gasoline 526-73-8 0.06

1,2,4-Trichlorobenzene Solvent 120-82-1 0.12

1,2,4-Trimethylbenzene Organic synthesis 95-63-6 0.056

1,2-Dibromo-3-chloropropane Fumigant 96-12-8 0.51

1,2-Dibromoethane Solvent 106-93-4 0.036

1,2-Dichlorobenzene Solvent 95-50-1 0.048

1,2-Dichloroethane Solvent 107-06-2 0.13

1,2-Dichloropropane Solvent 78-87-5 0.029

1,3,5-Trimethylbenzene Gasoline 108-67-8 0.044

1,3-Dichlorobenzene Solvent 541-73-1 0.03

1,3-Dichloropropane Organic synthesis 142-28-9 0.06

1,4-Dichlorobenzene Fumigant 106-46-7 0.034

2,2-Dichloropropane Organic synthesis 594-20-7 0.05

2-Butanone Solvent 78-93-3 4

2-Chlorotoluene Solvent 95-49-8 0.04

2-Hexanone Solvent 591-78-6 0.7

3-Chloropropene Organic synthesis 107-05-1 0.5

4-Chlorotoluene Solvent 106-43-4 0.05

4-Isopropyl-1-methylbenzene Organic synthesis 99-87-6 0.08

4-Methyl-2-pentanone Solvent 108-10-1 0.37

Acetone Solvent 67-64-1 6

Acrylonitrile Organic synthesis 107-13-1 0.8

Benzene Gasoline 71-43-2 0.021

Bromobenzene Solvent 108-86-1 0.028

Bromochloromethane Organic synthesis 74-97-5 0.12

Tables 29
Compound Primary use/source CAS number LRL

(μg/L)

Bromodichloromethane Disinfection by-product 75-27-4 0.028

Bromoethene Fire retardant 593-60-2 0.1

Bromoform (tribromomethane) Disinfection by-product 75-25-2 0.1

Bromomethane Fumigant 74-83-9 0.26

Butylbenzene Organic synthesis 104-51-8 0.12

Carbon disulfide Organic synthesis 75-15-0 0.038

Chlorobenzene Solvent 108-90-7 0.028

Chloroethane Solvent 75-00-3 0.12

Chloroform (trichloromethane) Disinfection by-product 67-66-3 0.024

Chloromethane Refrigerant 74-87-3 0.17

cis-1,2-Dichloroethylene Solvent 156-59-2 0.024

cis-1,3-Dichloropropene Fumigant 10061-01-5 0.05

Dibromochloromethane Disinfection by-product 124-48-1 0.1

Dibromomethane Solvent 74-95-3 0.05

Dichlorodifluoromethane (CFC-12) Refrigerant 75-71-8 0.18

Dichloromethane (methylene chloride) Solvent 75-09-2 0.06

Diethyl ether Solvent 60-29-7 0.08

Diisopropyl ether Gasoline 108-20-3 0.1

Ethyl methacrylate Organic synthesis 97-63-2 0.18

Ethyl tert-butyl ether (ETBE) Gasoline 637-92-3 0.05

Ethylbenzene Gasoline 100-41-4 0.03

Hexachlorobutadiene Organic synthesis 87-68-3 0.14

Hexachloroethane Solvent 67-72-1 0.14

Isopropylbenzene Organic synthesis 98-82-8 0.038

m- and p-Xylene Gasoline 108-38-3/106-42-3 0.06

Methyl acrylate Organic synthesis 96-33-3 2

Methyl acrylonitrile Organic synthesis 126-98-7 0.76

Methyl iodide Organic synthesis 74-88-4 0.35

Methyl methacrylate Organic synthesis 80-62-6 0.35

Methyl tert-butyl ether Gasoline 1634-04-4 0.17

Naphthalene Organic synthesis 91-20-3 0.52

n-Propylbenzene Solvent 103-65-1 0.042

o-Ethyl toluene Hydrocarbon 611-14-3 0.06

o-Xylene Gasoline 95-47-6 0.038

sec-Butylbenzene Organic synthesis 135-98-8 0.06

Styrene Organic synthesis 100-42-5 0.042

tert-Amtyl methyl ether Gasoline 994-05-8 0.08

tert-Butylbenzene Organic synthesis 98-06-6 0.06

Tetrachloroethylene (PCE) Solvent 127-18-4 0.06

Table 2A. Volatile organic compounds, primary use or source, Chemical Abstract Service (CAS) number, and laboratory reporting level 

(LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2020—Continued. 

[μg/L, micrograms per liter]

30 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Primary use/source CAS number LRL

(μg/L)

Tetrachloromethane (carbon tetrachloride) Solvent 56-23-5 0.06

Tetrahydrofuran Solvent 109-99-9 1

Toluene Gasoline 108-88-3 0.02

trans-1,2-Dichloroethylene Solvent 156-60-5 0.032

trans-1,3-Dichloropropene Fumigant 10061-02-6 0.09

trans-1,4-Dichloro-2-butene Organic synthesis 110-57-6 0.7

Trichloroethylene (TCE) Solvent 79-01-6 0.038

Trichlorofluoromethane (CFC-11) Refrigerant 75-69-4 0.16

Vinyl chloride Organic synthesis 75-01-4 0.06

Table 2A. Volatile organic compounds, primary use or source, Chemical Abstract Service (CAS) number, and laboratory reporting level 

(LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2020—Continued. 

[μg/L, micrograms per liter]

Compound Primary use/source CAS number LRL 

(mg/L)

Acetone Degradate 67-64-1 1.2

Diisopropyl ether Gasoline oxygenate 108-20-3 0.08

Ethyl tert-butyl ether Gasoline oxygenate 637-92-3 0.1

Methyl acetate Degradate 79-20-9 0.4

tert-Amyl alcohol Degradate 75-85-4 0.43

tert-Butyl alcohol Degradate 75-65-0 1

tert-Butyl methyl ether Gasoline oxygenate 1634-04-4 0.08

tert-Pentyl methyl ether Gasoline oxygenate 994-05-8 0.07

Table 2B. Gasoline oxygenates and gasoline oxygenate degradates, primary use or source, Chemical Abstract Service (CAS) number, 

and laboratory reporting level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 4024.

[mg/L, micrograms per liter]

Tables 31
Compound Primary use/source CAS number LRL 

(mg/L)

1-Naphthol Degradate 90-15-3 0.088

2,6-Diethylaniline Degradate 579-66-8 0.006

2-Chloro-2,6-diethylacetanilide Degradate 6967-29-9 0.005

2-Ethyl-6-methylaniline Degradate 24549-06-2 0.004

3,4-Dichloroaniline Degradate 95-76-1 0.004

4-Chloro-2-methylphenol Degradate 1570-64-5 0.005

Acetochlor Herbicide 34256-82-1 0.006

Alachlor Herbicide 15972-60-8 0.005

Atrazine Herbicide 1912-24-9 0.007

Azinphos-methyl oxygen analog Degradate 90-15-4 0.016

Azinphos-methyl Degradate 90-15-4 0.05

Benfluralin Degradate 579-66-9 0.01

Carbaryl Insecticide 63-25-2 0.041

Chlorpyrifos Insecticide 2921-88-2 0.005

Chlorpyrofos, oxygen analog Degradate 5598-15-2 0.056

cis-Permethrin Insecticide 54774-45-7 0.006

Cyfluthrin Insecticide 68359-37-5 0.008

Cypermethrin Insecticide 52315-07-8 0.008

Dacthal Herbicide 1861-32-1 0.003

Deethylatrazine Degradate 6190-65-4 0.006

Desulfinylfipronil Degradate NA 0.012

Desulfinylfipronil amide Degradate NA 0.029

Diazinon Insecticide 333-41-5 0.005

Diazinon, oxygen analog Insecticide 962-58-3 0.01

Dichlorvos Fumigant 62-73-7 0.011

Dicrotophos Insecticide 141-66-2 0.084

Dieldrin Insecticide 60-57-1 0.009

Dimethoate Insecticide 60-51-5 0.006

Ethion Insecticide 563-12-2 0.004

Ethion monoxon Degradate 17356-42-2 0.033

Fenamiphos Insecticide 22224-92-6 0.029

Fenamiphos sulfone Degradate 31972-44-8 0.007

Fenamiphos sulfoxide Degradate 31972-43-7 0.031

Fipronil Insecticide 120068-37-3 0.016

Fipronil sulfide Degradate 120067-83-6 0.013

Fipronil sulfone Degradate 120068-36-2 0.024

Fonofos Insecticide 944-22-9 0.003

Fonofos, oxygen analog Degradate 944-21-8 0.002

Hexazinone Herbicide 51235-04-2 0.012

Table 2C. Pesticides and pesticide degradates, primary use or source, Chemical Abstract Service (CAS) number, and laboratory 

reporting level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2003.

[NA, not available; mg/L, micrograms per liter]

32 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Primary use/source CAS number LRL 

(mg/L)

Iprodione Fungicide 36734-19-7 1.422

Isofenphos Insecticide 25311-71-1 0.003

Malaoxon Degradate 1634-78-2 0.008

Malathion Insecticide 121-75-5 0.027

Metalaxyl Fungicide 57837-19-1 0.005

Methidathion Insecticide 950-37-8 0.005

Metolachlor Herbicide 51218-45-2 0.013

Metribuzin Herbicide 21087-64-9 0.006

Myclobutanil Fungicide 88671-89-0 0.008

Paraoxon-methyl Degradate 950-35-6 0.029

Parathion-methyl Insecticide 298-00-0 0.015

Pendimethalin Herbicide 40487-42-1 0.022

Phorate Insecticide 298-02-2 0.011

Phorate oxygen analog Degradate 2600-69-3 0.097

Phosmet Insecticide 732-11-6 0.007

Phosmet oxon Degradate 3735-33-9 0.055

Prometon Herbicide 1610-18-0 0.005

Prometryn Herbicide 7287-19-6 0.005

Propyzamide Herbicide 23950-58-5 0.004

Simazine Herbicide 122-34-9 0.005

Tebuthiuron Herbicide 34014-18-1 0.016

Terbufos Insecticide 13071-79-9 0.017

Terbufos oxygen analog sulfone Degradate 56070-15-6 0.067

Terbuthylazine Herbicide 5915-41-3 0.010

Trifluralin Herbicide 1582-09-8 0.009

Table 2C. Pesticides and pesticide degradates, primary use or source, Chemical Abstract Service (CAS) number, and laboratory 

reporting limits (LRLs) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2003—Continued.

[NA, not available; mg/L, micrograms per liter]

Tables 33
Compound Primary use/source CAS number LRL 

(mg/L)

2,4-D Herbicide 94-75-7 0.021

2,4-D methyl ester Herbicide 1928-38-7 0.008

2,4-DB Herbicide 94-82-6 0.016

3(4-Chlorophenyl)-1-methyl urea Degradate 5352-88-5 0.024

3-Hydroxycarbofuran Degradate 16655-82-6 0.005

3-Ketocarbofuran Degradate 16709-30-1 0.014

Acifluorfen Herbicide 50594-66-6 0.006

Aldicarb Insecticide 116-06-3 0.04

Aldicarb sulfone Degradate 1646-88-4 0.02

Aldicarb sulfoxide Degradate 1646-87-3 0.008

Atrazine Herbicide 1912-24-9 0.009

Bendiocarb Insecticide 22781-23-3 0.025

Benomyl Fungicide 17804-35-2 0.003

Bensulfuron-methyl Herbicide 83055-99-6 0.015

Bentazon Herbicide 25057-89-0 0.011

Bromacil Herbicide 314-40-9 0.033

Bromoxynil Herbicide 1689-84-5 0.017

Caffeine Beverages 58-08-2 0.009

Carbaryl Insecticide 63-25-2 0.028

Carbofuran Herbicide 1563-66-2 0.005

Chloramben, methyl ester Herbicide 7286-84-2 0.018

Chlorimuron-ethyl Herbicide 90982-32-4 0.009

Chlorothalonil Herbicide 1897-45-6 0.035

Clopyralid Herbicide 1702-17-6 0.013

Cycloate Herbicide 1134-23-2 0.013

Dacthal monoacid Degradate 887-54-7 0.011

Deethylatrazine Degradate 6190-65-4 0.028

Deethyldeisopropylatrazine Degradate 3397-62-4 0.04

Deisopropylatrazine Degradate 1007-28-9 0.01

Dicamba Herbicide 1918-00-9 0.012

Dichlorprop Herbicide 120-36-5 0.013

Dinoseb Herbicide 88-85-7 0.012

Diphenamid Herbicide 957-51-7 0.026

Diuron Herbicide 330-54-1 0.015

Fenuron Herbicide 101-42-8 0.031

Flumetsulam Herbicide 98967-40-9 0.011

Fluometuron Herbicide 2164-17-2 0.031

Hydroxyatrazine Degradate 2163-68-0 0.008

Imazaquin Herbicide 81335-37-7 0.016

Table 2D. Pesticides, pesticide degradates, and caffeine, primary use or source, Chemical Abstract Service (CAS) number, and

 laboratory reporting level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2060.

[mg/L, micrograms per liter]

34 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Primary use/source CAS number LRL 

(mg/L)

Imazethapyr Herbicide 81335-77-5 0.017

Imidacloprid Insecticide 138261-41-3 0.006

Linuron Herbicide 330-55-2 0.014

MCPA Herbicide 94-74-6 0.016

MCPB Herbicide 94-81-5 0.015

Metalaxyl Fungicide 57837-19-1 0.02

Methiocarb Insecticide 2032-65-7 0.008

Methomyl Insecticide 16752-77-5 0.004

Metsulfuron methyl Herbicide 74223-64-6 0.025

Neburon Herbicide 555-37-3 0.012

Nicosulfuron Herbicide 111991-09-4 0.013

Norflurazon Herbicide 27314-13-2 0.016

Oryzalin Herbicide 19044-88-3 0.017

Oxamyl Insecticide 23135-22-0 0.012

Picloram Herbicide 6607 0.019

Propham Herbicide 122-42-9 0.009

Propiconazole Fungicide 60207-90-1 0.021

Propoxur Insecticide 114-26-1 0.008

Siduron Herbicide 1982-49-6 0.016

Sulfometuron-methyl Herbicide 74222-97-2 0.008

Tebuthiuron Herbicide 34014-18-1 0.006

Terbacil Herbicide 5902-51-2 0.009

Tribenuron-methyl Herbicide 101200-48-0 0.008

Triclopyr Herbicide 55335-06-3 0.022

Table 2D. Pesticides, pesticide degradates, and caffiene, primary use or source, Chemical Abstract Service (CAS) number, and 

laboratory reporting level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2060—Continued.

[mg/L, micrograms per liter]

Tables 35
Compound Primary use/source CAS number LRL

(mg/L)

1,4-Dichlorobenzene Moth repellant, fumigant, deodorant 106-46-7 0.5

1-Methylnaphthalene Gasoline, diesel fuel, or crude oil 90-12-0 0.5

2,6-Dimethylnaphthalene Diesel/kerosene (trace in gasoline) 581-42-0 0.5

2-Methylnaphthalene Gasoline, diesel fuel, or crude oil 91-57-6 0.5

3-beta-Coprostanol Carnivore fecal indicator 360-68-9 2

3-Methyl-1(H)-indole (Skatole) Fragrance, stench in feces and coal tar 83-34-1 1

3-tert-Butyl-4-hydroxy anisole (BHA) Antioxidant, general preservative 25013-16-5 5

4-Cumylphenol Nonionic detergent metabolite 599-64-4 1

4-n-Octylphenol Nonionic detergent metabolite 1806-26-4 1

4-tert-Octylphenol Nonionic detergent metabolite 140-66-9 1

5-Methyl-1H-benzotriazole Antioxidant in antifreeze and deicers 136-85-6 2

Acetophenone Fragrance in detergent and tobacco, flavor in 

beverages 

98-86-2 0.5

Acetyl hexamethyl tetrahydronaphthalene 

(AHTN) 

Musk fragrance 21145-77-7 0.5

Anthracene Wood preservative, tar, diesel, crude oil, 

combustion product 

120-12-7 0.5

Anthraquinone Manuf dye/textiles, seed treatment, bird repellant 84-65-1 0.5

Benzo[a]pyrene Cancer research, combustion product 50-32-8 0.5

Benzophenone Fixative for perfumes and soaps 119-61-9 0.5

beta-Sitosterol Plant sterol 83-46-5 2

beta-Stigmastanol Plant sterol 19466-47-8 2

Bisphenol A Manuf polycarbonate resins, antioxidant, flame 

retardant

80-05-7 1

Bromacil Herbicide, >80 percent noncrop usage on grass/

brush 

314-40-9 0.5

Bromoform Byproduct waste water treatment, military/

explosives 

75-25-2 0.5

Caffeine Beverages 58-08-2 0.5

Camphor Flavor, odorant, ointments 76-22-2 0.5

Carbaryl Insecticide, crop and garden uses 63-25-2 1

Carbazole Insecticide, manuf. dyes, explosives, and 

lubricants 

86-74-8 0.5

Chlorpyrifos Insecticide, domestic pest and termite control 2921-88-2 0.5

Cholesterol Fecal indicator, plant sterol 57-88-5 2

Cotinine Primary nicotine metabolite 486-56-6 1

Diazinon Insecticide, >40 percent nonagricultural usage, 

ants, flies 

333-41-5 0.5

Dichlorvos Insecticide degradate of naled or trichlofon 62-73-7 1

d-Limonene Fungicide, antimicrobial, antiviral, fragrance in 

aerosols 

5989-27-5 0.5

Fluoranthene Component of coal tar and asphalt 206-44-0 0.5

Table 2E. Waste-water indicator compounds, primary use or source, Chemical Abstract Service (CAS) number, and laboratory reporting 

level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 1433.

[mg/L, micrograms per liter]

36 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Primary use/source CAS number LRL

(mg/L)

Hexadydrohexamethylcyclopentabenzopyran 

(HHCB) 

Musk fragrance 1222-05-5 0.5

Indole Pesticide ingredient, fragrance in coffee 120-72-9 0.5

Isoborneol Fragrance in perfumery, in disinfectants 124-76-5 0.5

Isophorone Solvent for lacquer, plastic, oil, silicon, resin 78-59-1 0.5

Isopropylbenzene Manuf phenol/acetone, fuels and paint thinner 98-82-8 0.5

Isoquinoline Flavors and fragrances 119-65-3 0.5

Menthol Cigarettes, cough drops, liniment, mouthwash 89-78-1 0.5

Metalaxyl Herbicide, fungicide, mildew, blight, pathogens, 

golf/turf 

57837-19-1 0.5

Methyl salicylate Liniment, food, beverage, UV-absorbing lotion 119-36-8 0.5

Metolachlor Herbicide, indicator of agricultural drainage 51218-45-2 0.5

N,N-diethyl-meta-toluamide (DEET) Insecticide, urban uses, mosquito repellent 134-62-3 0.5

Naphthalene Fumigant, moth repellent, major component of 

gasoline 

91-20-3 0.5

Nonylphenol, diethoxy- (total) Nonionic detergent metabolite 26027-38-2 5

Octylphenol, diethoxy- (OPEO2) Nonionic detergent metabolite 26636-32-8 1

Octylphenol, monoethoxy- (OPEO1) Nonionic detergent metabolite 26636-32-8 1

para-Nonylphenol (total) Nonionic detergent metabolite 84852-15-3 5

p-Cresol Wood preservative 106-44-5 1

Pentachlorophenol Herbiicide, fumigant, wood preservative, termite 

control 

87-86-5 2

Phenanthrene Manuf. explosives, tar, diesel, crude oil, combustion product 85-01-8 0.5

Phenol Disinfectant, product manufacturing, leachate 108-95-2 0.5

Prometon Herbicide (non-crop only) applied prior to blacktop 1610-18-0 0.5

Pyrene Component of coal tar and asphalt 129-00-0 0.5

Tetrachloroethylene Solvent, degreaser, veterinary anthelmintic 127-18-4 0.5

Tri(2-butoxyethyl)phosphate Flame retardant 78-51-3 0.5

Tri(2-chloroethyl)phosphate Plasticizer, flame retardant 115-96-8 0.5

Tributyl phosphate Antifoaming agent, flame retardant 126-73-8 0.5

Triclosan Disinfectant, antimicrobial 3380-34-5 1

Triethyl citrate (ethyl citrate) Cosmetics, pharmaceuticals 77-93-0 0.5

Triphenyl phosphate Plasticizer, resin, wax, finish, roofing paper, flame 

retardant

115-86-6 0.5

Tris(dichlorisopropyl)phosphate Flame retardant 13674-87-8 0.5

Table 2E. Waste-water indicator compounds, primary use or source, Chemical Abstract Service (CAS) number, and laboratory reporting 

level (LRL) for the U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 1433—Continued.

[mg/L, micrograms per liter]

Tables 37
Table 2F. Pharmaceutical compounds, primary use or source, Chemical Abstract Service (CAS) number, and method detection limit 

(MDL) for the U.S. Geological Survey’s National Water Quality Laboratory custom laboratory code 9003.

[CNS, central nervous system; NA, not available; mg/L, micrograms per liter]

Compound Primary use/source CAS number MDL 

(μg/L)

1,7-dimethylxanthine CNS stimulant 611-59-6 0.019

Acetaminophen Analgesic 103-90-2 0.008

Azithromycin Antibacterial 83905-01-5 NA

Caffeine Beverages 58-08-2 0.014

Carbamazepine Anticonvulsant 298-46-4 NA

Cimetidine1 Antihistamine 51481-61-9 0.006

Codeine Analgesic 76-57-3 NA

Cotinine CNS stimulant 486-56-6 0.023

Dehydronifedipine Antianginal (metabolite) 67035-22-7 0.009

Diltiazem1 Antiangina, antihypertensive 42399-41-7 0.012

Diphenhydramine1 Antihistamine 58-73-1 NA

Erythromycin Antibacterial 114-07-8 NA

Fluoxetine1 Antidepressant 54910-89-3 0.018

Furosemide Diuretic 54-31-9 NA

Gemfibrozil1 Antihyperlipidemic 25812-30-0 0.015

Ibuprofen1 Analgesic 15687-27-1 0.018

Metformin Antihyperglycemic 657-24-9 0.003

Miconazole Antifungal 22916-47-8 NA

Ranitidine1 Antihistamine 66357-35-5 0.01

Salbutamol (Albuterol) Antiasthmatic 18559-94-9 0.03

Sulfamethoxazole1 Antibacterial 723-46-6 0.023

Thiabendazole Antiparasitic 148-79-8 NA

Trimethoprim Antibacterial 738-70-5 0.014

Warfarin Anticoagulant 81-81-2 0.006

1

Concentrations of these compounds are reported as estimates only.

38 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 2G. The emerging contaminant compounds perchlorate, 1,4-dioxane, and N-nitrosodimethylamine (NDMA), Chemical Abstract 

Service (CAS) number, and minimum reporting level (MRL) for Montgomery Watson Harza Laboratory.

[ug/L, micrograms per liter]

Compound Primary use/source CAS number MRL 

(mg/L)

Perchlorate Rocket fuel, fireworks, flares 14797-73-0 0.25, 0.5, 1.0, 2.0

1,4-dioxane Solvent stabilizer, solvent 123-91-1 2

N-Nitrosodimethylamine Rocket fuel manuf., plasticizer 62-75-9 0.002

Table 2H. Nutrients and dissolved organic carbon, Chemical Abstract Service (CAS) number, and laboratory reporting level (LRL) for the 

U.S. Geological Survey’s National Water Quality Laboratory analytical schedule 2755 and laboratory code 2613.

[NA, not available; mg/L, micrograms per liter]

Compound CAS number LRL 

(mg/L)

Ammonia 7664-41-7 0.04

Nitrite 14797-65-0 0.008

Nitrate plus nitrite NA 0.06

Total nitrogen (ammonia, nitrite, nitrate, organic nitrogen) 17778-88-0 0.03

Phosphorus, phosphate, ortho 14265-44-2 0.006

Dissolved organic carbon NA 0.3

Tables 39
Compound CAS number LRL

Major Ions, mg/L

Bromide 24959-67-9 0.02

Calcium 7440-70-2 0.02

Chloride 16887-00-6 0.2

Fluoride 16984-48-8 0.1

Magnesium 7439-95-4 0.008

Potassium 2023695 0.16

Silica 7631-86-9 0.04

Sodium 7440-23-5 0.2

Sulfate 14808-79-8 0.18

Residue on evaporation NA 10

Trace Elements, μg/L

Aluminum 7429-90-5 1.6

Antimony 7440-36-0 0.2

Arsenic 7440-38-2 0.2

Barium 7440-39-3 0.2

Beryllium 7440-41-7 0.06

Boron 7440-42-8 8

Cadmium 7440-43-9 0.04

Chromium 7440-47-3 0.8

Cobalt 7440-48-4 0.014

Copper 7440-50-8 0.4

Iron 7439-89-6 6

Lead 7439-92-1 0.08

Lithium 7439-93-2 0.6

Manganese 7439-96-5 0.2

Mercury 7439-97-6 0.01

Molybdenum 7439-98-7 0.4

Nickel 7440-02-0 0.06

Selenium 7782-49-2 0.4

Silver 7440-22-4 0.2

Strontium 7440-24-6 0.4

Thallium 7440-28-0 0.04

Tungsten 7440-33-7 0.5

Uranium 7440-61-1 0.04

Vanadium 7440-62-2 0.14

Zinc 7440-66-6 0.6

Table 2I. Major ions and trace elements, Chemical Abstract Service (CAS) number, and laboratory reporting level (LRL) for the U.S.

Geological Survey’s National Water Quality Laboratory analytical schedule 1948.

[NA, not available; mg/L, micrograms per liter; mg/L, milligrams per liter]

40 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Constituent CAS number MDL

(μg/L)

Iron 7439-89-6 1

Iron (II) 7439-89-6 1

Arsenic 7440-38-2 0.5

Arsenic (III) 1327-53-3 1

Chromium 7440-47-3 0.1

Hexvalent chromium 11104-59-9 0.1

Table 2J. Iron, arsenic, and chromium speciation, Chemical Abstract Service (CAS) number, and method detection limit (MDL) for the 

U.S. Geological Survey’s National Research Program Laboratory, Boulder, Colorado.

[mg/L, micrograms per liter; oxidation states in parentheses]

Table 2K. Isotopic and radioactive constituents, Chemical Abstract Service (CAS) number, reporting level type, reporting level/uncertainty, and reporting units for the U.S. Geological Survey’s National Water Quality Laboratory, Stable Isotope and Tritium Laboratory, 

Menlo Park, Californiaa, Stable Isotope Laboratory, Reston, Virginiab, and the contract laboratories Eberline Analytical Servicesc and 

University of Arizona, Accelerator Mass Spectrometry Laboratoryd.

[NA, not applicable; SSMDC, sample specific minimum detectable concentration; MU, method uncertainty; pCi/L, pico curies per liter]

Constituent CAS number Reporting 

level type

Reporting level/

uncertainty Reporting units

Radon-222 14859-67-7 SSMDC 26 pCi/L

Tritiuma 10028-17-8 SSMDC 1 pCi/L

Deuterium/protiumb 7782-39-0/1333-74-0 MU 2 per mil

Oxygen-18/oxygen-16b NA/7782-44-7 MU 0.2 per mil

Gross-alpha radioactivity, 72-hr countc 12587-46-1 SSMDC 3 pCi/L

Gross-alpha radioactivity, 30-day countc 12587-46-1 SSMDC 3 pCi/L

Gross-beta radioactivity, 72-hr countc 12587-47-2 SSMDC 4 pCi/L

Gross-beta radioactivity, 30-day countc 12587-47-2 SSMDC 4 pCi/L

Radium-226c 13982-63-3 SSMDC 0.04 pCi/L

Radium-228c 15262-20-1 SSMDC 1 pCi/L

Carbon-13/Carbon-12d NA/7440-44-0 NA NA NA

Carbon-14d 14762-75-5 NA NA NA

Tables 41
Compound CAS number MU 

(percent) Unit

Tritium 10028-17-8 NA pCi/L

Helium-3/Helium-4 ND/7440-59-7 0.75 NA

Helium-4 7440-59-7 2 cm3STP/g

Argon 7440-37-1 2 cm3STP/g

Krypton 7439-90-9 2 cm3STP/g

Neon 7440-01-09 2 cm3STP/g

Xenon 7440-63-3 2 cm3STP/g

Table 2L. Tritium and noble gases, Chemical Abstract Service (CAS) number, method uncertainty (MU), and reporting units for 

Lawrence Livermore National Laboratory.

[NA, not available; ND, no data; pCi/L, picocuries per liter; cm3STP/g, cubic centimeter of gas at standard temperature and pressure per gram of water]

Table 2M. Microbial constituents, primary use and source, and method detection limit (MDL) for the U.S. Geological Survey’s Ohio 

Microbiology Laboratory parameter codes 90901, 90900, 99335, and 99332.

[NA, not available; ml, milliliters]

Microbial constituent Primary use/source MDL

Total coliforms Water quality indicator/Soil, water and intestinal tracts of animals 1 colony/100ml

Escherichia coliform Sewage and animal waste indicator/ Intestinal tracts of humans and animals 1 colony/100ml

F-specific coliphage Viral indicator/Intestinal tracts of warm-blooded animals NA

Somatic coliphage Viral indicator/Fecal contaminated waters NA

42 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification 

No.

Sampling information Construction information

Date Time Sampling 

schedule

Year of 

construction

Well

depth, 

(ft below LSD)

Top 

perforation, 

(ft below LSD)

Bottom 

perforation, 

(ft below LSD)

SDTEM-01 05/18/04 1130 Expanded 1965 1,000 150 1,000

SDTEM-02 05/24/04 1010 Basic NA NA 320 1,110

SDTEM-03 05/24/04 1200 Basic NA NA 466 909

SDTEM-04 05/24/04 1400 Basic NA NA 109 245

SDTEM-05 05/25/04 1200 Expanded 1967 960 200 900

SDTEM-06 05/26/04 1130 Expanded NA NA 170 470

SDTEM-07 05/27/04 1040 Basic 1962 307 60 307

SDTEM-08 05/27/04 1150 Basic 1965 NA 114 426

SDTEM-09 05/27/04 1350 Basic NA NA 450 950

SDTEM-10 05/27/04 1440 Expanded NA NA 50 210

SDTEM-11 06/16/04 1500 Basic NA 1,000 340 980

SDTEM-12 06/21/04 1130 Expanded NA NA 96 542

SDTEM-13 06/22/04 1130 Expanded NA 860 235 860

SDTEM-14 06/23/04 1200 Expanded NA NA 270 1,000

SDTEMFP-01 05/19/04 1200 Expanded 1951 NA 234 1,223

SDTEMFP-02 05/20/04 1330 Expanded NA NA 378 838

SDTEMFP-03 06/14/04 1120 Expanded NA NA 313 853

SDTEMFP-04 06/15/04 1220 Expanded NA 480 75 465

SDTEMFP-05 06/16/04 1020 Basic NA 280 80 270

SDWARN-01 06/17/04 1030 Basic plus 1957 473 113 473

SDWARN-02 06/17/04 1130 Basic plus 1976 NA 100 575

SDWARN-03 06/17/04 1400 Basic plus 1951 550 118 550

SDWARN-04 06/24/04 0900 Expanded 1957 438 170 438

SDWARN-05 06/28/04 1000 Expanded 1957 743 130 743

SDWARN-06 06/29/04 1000 Expanded 1957 730 190 730

SDWARN-07 07/13/04 0920 Basic plus 1984 295 70 165

SDWARN-08 07/13/04 1110 Basic plus 1987 700 280 600

SDWARN-09 07/13/04 1320 Basic plus 1996 642 60 642

SDALLV-01 06/30/04 1130 Expanded 1999 200 100 180

SDALLV-02 07/01/04 1210 Expanded 1957 130 94 117

SDALLV-03 07/12/04 1150 Expanded 1998 606 222 566

SDALLV-04 07/12/04 1330 Basic plus 2003 180 80 180

SDALLV-05 07/12/04 1630 Basic plus 1961 582 234 513

SDALLV-06 07/13/04 1100 Expanded 1995 200 100 142

SDALLV-07 07/14/04 0900 Basic plus 1952 199 39 NA

SDALLV-08 07/14/04 1100 Basic plus NA 87 50 78

Table 3. Identification, sampling, and construction information for sampled wells in the San Diego Ground-Water Ambient Monitoring 

and Assessment (GAMA) study unit, California, May to July 2004.

[ft, foot; LSD, land surface datum; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley 

study area; SDALLV, alluvial study area; SDHDRK, hard rock study area; NA, not available]

Tables 43
GAMA

 identification 

No.

Sampling information Construction information

Date Time Sampling 

schedule

Year of 

construction

Well

depth, 

(ft below LSD)

Top 

perforation, 

(ft below LSD)

Bottom 

perforation, 

(ft below LSD)

SDALLV-09 07/14/04 1110 Expanded 1983 810 690 800

SDALLV-10 07/14/04 1340 Basic plus 1995 135 65 130

SDALLV-11 07/15/04 0910 Basic plus 1992 405 50 148

SDALLV-12 07/15/04 1030 Basic plus 1996 230 60 220

SDALLV-13 07/15/04 1040 Expanded 2001 NA 96 176

SDALLV-14 07/15/04 1310 Basic plus 1978 80 40 80

SDALLV-15 07/27/04 1250 Basic plus 1995 107 54 107

SDALLV-16 07/28/04 0900 Basic plus 1956 120 48 NA

SDALLV-17 07/29/04 1000 Basic plus 1966 NA NA NA

SDHDRK-01 07/12/04 1030 Basic plus 1997 906 110 906

SDHDRK-02 07/13/04 1510 Basic plus 1987 92 52 92

SDHDRK-03 07/15/04 1530 Basic plus NA 510 80 510

SDHDRK-04 07/19/04 1410 Expanded 1964 315 NA NA

SDHDRK-05 07/20/04 1100 Expanded 1987 450 50 450

SDHDRK-06 07/21/04 1130 Expanded 1991 1,000 52 1,000

SDHDRK-07 07/22/04 1130 Expanded 1994 400 97 400

SDHDRK-08 07/27/04 1000 Basic plus 1997 500 60 500

SDHDRK-09 07/27/04 1510 Basic plus 1975 400 75 400

SDHDRK-10 07/28/04 1140 Basic plus NA NA NA NA

SDHDRK-11 07/28/04 1550 Basic plus 1972 455 20 455

SDHDRK-12 07/29/04 1300 Basic plus 1990 186 60 186

SDHDRK-13 07/29/04 1500 Basic plus NA 46 41 NA

Table 3. Identification, sampling, and construction information for sampled wells in the San Diego Ground -Water Ambient Monitoring 

and Assessment (GAMA) study unit, California, May to July 2004—Continued.

[ft, foot; LSD, land surface datum; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley 

study area; SDALLV, alluvial study area; SDHDRK, hard rock study area; NA, not available]

44 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 4. Compounds analyzed for in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004, that appear on multiple analytical schedules, primary compound classification, analytical schedules compound appears on, and preferred analytical schedule.

[VOC, volatile organic compound]

Compound Primary classification Analytical schedules Preferred1 analytical schedule

Acetone VOC 2020, 4204 2020

Diisopropyl ether VOC 2020, 4204 2020

Methyl tert-butyl ether VOC 2020, 4204 2020

Methyl tert-pentyl ether VOC 2020, 4204 2020

tert-Butyl ethyl ether VOC 2020, 4204 2020

1,4-Dichlorobenzene VOC 1433, 2020 2020

Isopropylbenzene VOC 1433, 2020 2020

Naphthalene VOC 1433, 2020 2020

Tetrachloroethene VOC 1433, 2020 2020

Tribromomethane VOC 1433, 2020 2020

Caffeine Waste-water indicator 1433, 2060, 9003 2060

Cotinine Waste-water indicator 1433, 9003 1433

Atrazine Pesticide 2003, 2060 2003

Bromacil Pesticide 1433, 2060 2060

Carbaryl Pesticide 1433, 2003, 2060 2003

Chlorpyrifos Pesticide 1433, 2003 2003

Deethyl atrazine Pesticide degradate 2003, 2060 2003

Diazinon Pesticide 1433, 2003 2003

Dichlorvos Pesticide 1433, 2003 2003

Metalaxyl Pesticide 1433, 2003, 2060 2060

Metolachlor Pesticide 1433, 2003 2003

Prometon Pesticide 1433, 2003 2003

1

Preferred analytical schedules are the most accurate and precise methods of analysis for the compound shown.

Tables 45
Table 5. Quality-control summary for volatile organic compounds and gasoline oxygenates, waste-water indicator compounds, 

emerging contaminant compounds, pesticide compounds, nutrients and dissolved organic carbon, major ions, and trace elements 

detected in trip blanks, equipment blanks, field blanks anc ground-water samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004.

[μg/L, micrograms per liter; E, estimated value; NA, not available; NC, sample not collected; —, not detected; NDMA, N-nitrosodimethylamine]

Compounds 

Number 

of trip 

blank detections/

analyses

Maximum 

concentration detected 

in trip blank 

samples, μg/L 

Number of 

equipment 

blank detections/

analyses

Maximum 

concentration detected 

in equipment blank 

samples, μg/L 

Number of 

field blank 

detections/

analyses

Maximum 

concentration 

detected in 

field blank 

samples, 

μg/L 

Minimum 

concentration 

detected in 

ground-water samples, 

μg/L

Number of 

ground-water samples 

censored

Volatile Organic Compounds and Gasoline Oxygenates

Trichloromethane 0/1 — 0/1 — 1/51 0.13 — 0

Toluene 0/1 — 0/1 — 1/51 E0.02 — 0

Acetone 0/1 — 0/1 — 1/51 E3 — 0

Waste-Water Indicator Compounds

Phenol NC NC NC NC 2/42 E0.2 E0.1 183

Emerging Contaminant Compounds

NDMA NC NC NC NC 1/51 0.005 — 0

Pesticide Compounds

None detected NC NC NC NC 0/5 NA NA NA

Nutrients and Dissolved Organic Carbon

None detected NC NC 0/14 NC 0/2 NA NA NA

Major Ions

Sodium NC NC NC NC 0.15 14.55 0

Silica NC NC NC NC 2/2 0.065 13.15 0

Calcium NC NC NC NC 2/2 0.025 4.175 0

Trace Elements

Copper NC NC 1/2 0.9 1/2 1.2 E0.2 15

Vanadium NC NC 0/2 — 1/2 0.8 0.2 3

Zinc NC NC 0/2 — 1/2 0.3 E0.3 1

1

Compounds also detected in associated source solution blanks. 

2

Waste-water indicator compound detected in one of two associated source solution blanks.

3

Because of ongoing problems with the analytical procedures used to determine phenol, all ground-water samples with concentrations less than 0.4 μg/L 

are censored.

4

Dissolved organic carbon not determined. 

5

Concentration in milligrams per liter.

46 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 6A. Quality-control summary of replicate volatile organic compounds and gasoline oxygenates, pesticides and pesticide 

degradates, and emerging contaminant samples with relative standard deviations greater than zero, collected for the San Diego 

Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

[NA, not available; no replicate pairs of waste-water compounds, or coliphage, had a relative standard deviation greater than zero]

Compound1 Number of relative standard 

deviations greater than 

zero/replicate pairs

Maximum relative

 standard deviation 

(percent)

Median of relative

 standard deviations 

greater than zero 

(percent)

Volatile Organic Compounds and Gasoline Oxygenates

Dichloromethane 1/5 4 NA

Chloroform 2/5 4 3

Tetrachloroethene 1/5 2 NA

Bromodichloromethane 1/5 1 NA

Pesticides and Pesticide Degradates

3,4-Dichloroaniline 1/5 7 NA

Hexazinone 1/5 6 NA

Simazine 1/5 5 NA

Atrazine 1/5 5 NA

Terbuthylazine 1/5 2 NA

Prometryn 1/5 2 NA

Deethylatrazine 1/5 1 NA

Prometon 1/5 1 NA

Emerging Contaminants

Perchlorate 2/5 21 13

1

Due to the large number of compounds, only compounds with relative standard deviations above zero are shown.

Tables 47
Table 6B. Quality-control summary of replicate nutrient and dissolved organic carbon samples collected for the San Diego Ground 

Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

[NA, not available]

Compound 

Number of relative

 standard deviations

 greater than

 zero/replicate pairs

Maximum relative

 standard deviation 

(percent)

Median of relative

 standard deviations

 greater than zero 

(percent)

Dissolved organic carbon 2/2 7 9.3

Phosphorus 1/2 1 NA

Total nitrogen 1/2 1 NA

Nitrate plus nitrite 0/2 0 NA

Ammonia 0/2 0 NA

Nitrite 0/2 0 NA

Table 6C. Quality-control summary of replicate major ion samples collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004.

[NA, not available]

Constituent 

Number of relative

 standard deviations

 greater than

 zero/replicate pairs

Maximum relative

 standard deviation 

(percent)

Median of relative

 standard deviations

 greater than zero 

(percent)

Bromide 2/2 7 4

Potassium 2/2 3 2

Sulfate 2/2 3 2

Magnesium 2/2 2 2

Sodium 2/2 2 1

Chloride 2/2 2 2

Fluorine 1/2 1 NA

Residue on evaporation 2/2 1 1

Calcium 1/2 1 NA

Silica 2/2 1 1

48 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 6D. Quality-control summary of replicate trace-element samples collected for the San Diego Ground-Water Ambient Monitoring 

and Assessment (GAMA) study, California, May to July 2004.

[NA, not available]

Constituent 

Number of relative 

standard deviations

 greater than 

zero/replicate pairs

Maximum relative 

standard deviation 

(percent)

Median of relative 

standard deviations

greater than zero 

(percent)

Chromium (VI)1 2/5 85 66

Chromium1 3/5 57 47

Vanadium 2/2 31 16

Nickel 2/2 20 16

Arsenic 2/2 14 10

Cadmium 1/2 10 NA

Selenium 2/2 8 7

Lead 2/2 8 5

Copper 2/2 7 6

Cobalt 2/2 6 4

Boron 2/2 5 3

Chromium 1/2 3 NA

Barium 2/2 2 1

Uranium 2/2 2 1

Zinc 2/2 2 1

Manganese 2/2 2 1

Strontium 2/2 2 1

Molybdenum 2/2 1 1

Lithium 1/2 1 NA

Iron 0/2 0 NA

Tungsten 0/2 0 NA

Aluminum 0/2 0 NA

Antimony 0/2 0 NA

Beryllium 0/2 0 NA

Iron1 0/2 0 NA

Iron (II)1 0/2 0 NA

Arsenic1 0/2 0 NA

Arsenic (III)1 0/2 0 NA

Mercury 0/2 0 NA

Silver 0/2 0 NA

Thallium 0/2 0 NA

1

Samples analyzed at U.S. Geological Survey national research program laboratory, Boulder, Colorado.

Tables 49
Table 6E. Quality-control summary of replicate isotope and radioactivity samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004.

[NA, not available]

Isotopes and radioactive

constituents 

Number of relative 

standard deviations 

greater than 

zero/replicate pairs

Maximum relative 

standard deviation

 (percent)

Median of relative 

standard deviations 

greater than zero 

(percent)

Alpha radioactivity, 30 day count 2/2 66 63

Alpha radioactivity, 72 hour count 1/2 6 NA

Beta radioactivity, 30 day count 2/2 17 17

Beta radioactivity, 72 hour count 2/2 21 19

Carbon-13/Carbon-12 1/1 19 NA

Carbon-14 fraction modern 1/1 1 NA

Deuterium/Protium 1/5 1 NA

Oxygen-18/Oxygen-16 1/5 1 NA

Radium-226 2/2 6 4

Radium-228 2/2 37 32

Radon-222 1/2 11 NA

Tritium1 4/4 91 7

Tritium2 5/5 18 9

1

Analysis done at Lawrence Livermore National Laboratory. 

2

Analysis done at U.S. Geological Survey, Menlo Park, California.

50 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 7A. Quality-control summary of volatile organic compound, gasoline oxygenate, NDMA, and 1,4-dioxane matrix spike recoveries 

for samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

Compound Number of 

spike samples

Minimum recovery 

(percent)

Maximum recovery 

(percent)

Median recovery 

(percent)

Acetone1 4 128 171 140

Chloromethane 4 88 153 132

trans-1,4-Dichloro-2-butene 4 111 135 132

2-Butanone 4 112 144 130

Vinyl chloride 4 105 150 126

Bromomethane 4 70 156 126

1,1-Dichloroethane 4 115 137 125

1,2-Dichloroethane 4 114 135 123

Chloroethane 4 112 137 123

Acrylonitrile 4 113 137 122

Ethyl tert-butyl ether (ETBE)1 4 113 135 119

Tetrahydrofuran 4 112 137 119

Bromodichloromethane 4 110 130 119

1,1,1-Trichloroethane (TCA) 4 107 127 118

Methyl acrylate 4 116 143 118

Trichlorofluoromethane (CFC-11) 4 115 138 118

3-Chloropropene 4 111 133 117

Diethyl ether 4 114 140 116

1,1-Dichloropropene 4 107 122 116

Benzene 4 110 127 116

2-Hexanone 4 98 120 116

Bromoethene 4 106 138 115

Chloroform (trichloromethane) 4 113 131 115

Methyl acrylonitrile 4 106 128 115

Methyl tert-Butyl methyl ether1 4 109 130 114

cis-1,2-Dichloroethylene 4 109 130 113

Diisopropyl ether1 4 111 130 113

Tetrachloromethane (carbon tetrachloride) 4 102 127 113

2,2-Dichloropropane 4 97 115 112

Dibromomethane 4 102 125 112

1,2,3,5-Tetramethylbenzene (isodurene) 4 99 116 112

1,2,3-Trichloropropane 4 97 114 112

1,3-Dichloropropane 4 102 118 111

Dichloromethane (methylene chloride) 4 107 131 111

4-Methyl-2-pentanone 4 99 118 111

1,1,2-Trichlorotrifluoroethane (CFC-113) 4 103 121 111

1,1-Dichloroethylene 4 105 126 111

tert-Amtyl methyl ether1 4 104 122 111

tert-Amyl alcohol 4 91 129 110

1,1,2,2-Tetrachloroethane 4 102 121 109

Tables 51
Compound Number of 

spike samples

Minimum recovery 

(percent)

Maximum recovery 

(percent)

Median recovery 

(percent)

1,2-Dibromoethane 4 95 114 109

tert-Butyl alcohol 4 87 126 109

Ethyl methacrylate 4 98 117 109

trans-1,2-Dichloroethylene 4 106 125 109

tert-Butylbenzene 4 97 115 108

1,1,2-Trichloroethane 4 100 125 108

Bromochloromethane 4 101 121 108

Dibromochloromethane 4 97 115 107

1,2,4-Trimethylbenzene 4 96 110 106

1,2-Dichloropropane 4 99 119 106

Trichloroethylene (TCE) 4 100 115 106

o-Xylene 4 94 108 106

1,1,1,2-Tetrachloroethane 4 93 112 105

1,2-Dibromo-3-chloropropane 4 103 123 105

1,2,3-Trimethylbenzene 4 93 110 105

Methyl acetate 4 101 115 104

NDMA 3 94 113 104

1,2-Dichlorobenzene 4 97 115 104

Toluene 4 100 110 103

Ethylbenzene 4 93 109 103

Chlorobenzene 4 91 106 103

Isopropylbenzene 4 91 107 103

Bromoform (tribromomethane) 4 93 110 102

m- and p-Xylene 4 92 106 102

1,3,5-Trimethylbenzene 4 92 104 101

sec-Butylbenzene 4 92 105 101

trans-1,3-Dichloropropene 4 96 112 101

Methyl methacrylate 4 92 110 101

2-Chlorotoluene 4 88 101 100

1,2,3-Trichlorobenzene 4 96 115 100

Bromobenzene 4 90 105 100

1,3-Dichlorobenzene 4 93 108 100

1,2,3,4-Tetramethylbenzene 4 90 104 99

o-Ethyl toluene 4 91 102 99

Naphthalene 4 89 107 98

Hexachloroethane 4 90 105 98

Tetrachloroethylene (PCE) 4 93 106 98

4-Isopropyl-1-methylbenzene 4 88 101 97

n-Propylbenzene 4 87 100 96

4-Chlorotoluene 4 91 103 95

Table 7A. Quality-control summary of volatile organic compound, gasoline oxygenate, NDMA, and 1,4-dioxane matrix spike

 recoveries for samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004—Continued.

52 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Number of 

spike samples

Minimum recovery 

(percent)

Maximum recovery 

(percent)

Median recovery 

(percent)

1,2,4-Trichlorobenzene 4 89 110 95

Hexachlorobutadiene 4 84 101 94

cis-1,3-Dichloropropene 4 90 104 94

1,4-Dichlorobenzene 4 91 107 93

Carbon disulfide 4 86 110 91

Methyl iodide 4 72 94 90

1,4-dioxane 2 78 99 88

Dichlorodifluoromethane (CFC-12) 4 73 111 87

Butylbenzene 4 80 93 86

Styrene 4 4 101 53

1

Compounds on schedules 2020 and 4024; only 2020 values are reported because it is the preferred analytical schedule.

Table 7A. Quality-control summary of volatile organic compound, gasoline oxygenate, NDMA, and 1,4-dioxane matrix spike 

recoveries for samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, 

May to July 2004—Continued.

Tables 53
Table 7B. Quality-control summary of matrix pesticide spike recoveries for samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004.

[—, not detected]

Compound Number of

 spike samples

Minimum 

recovery

 (percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Imazaquin 2 144 271 208

Flumetsulam 2 136 241 189

Imazethapyr 2 175 185 180

Imidacloprid 2 152 194 173

Hydroxyatrazine 2 147 146 147

2,4-D 2 135 146 141

Sulfometuron 2 139 142 140

Bensulfuron 2 113 159 136

Norflurazon 2 110 146 128

Siduron 2 111 137 124

Diphenamid 2 104 145 124

Propiconazole 2 101 139 120

Propham 2 107 133 120

Fluometuron 2 107 129 118

Linuron 2 108 128 118

Methiocarb 2 107 129 118

Diuron 2 109 126 117

Deethylde-isopropyl-atrazine 2 111 123 117

Chloramben methyl ester 2 92 140 116

Neburon 2 105 127 116

Terbacil 2 99 127 113

Acifluorfen 2 106 119 113

Dacthal monoacid 2 106 111 109

Picloram 2 95 122 109

Propoxur 2 97 120 108

Oryzalin 2 94 120 107

3-Hydroxy carbofuran 2 95 118 107

Fenuron 2 95 118 106

Dinoseb 2 86 126 106

Clopyralid 2 83 129 106

N-(4-Chlorophenyl)-N’-methylurea 2 87 123 105

Dicamba 2 91 119 105

Terbuthylazine 4 72 120 104

Chlorimuron 2 108 99 104

Carbofuran 2 99 107 103

Bromacil 2 91 114 103

Methomyl 2 93 112 103

2,4-D methyl ester 2 90 113 102

54 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Number of

 spike samples

Minimum 

recovery

 (percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Dacthal 4 76 120 102

Nicosulfuron 2 70 132 101

Atrazine1 4 70 120 101

Metalaxyl1 4 62 109 100

Bromoxynil 2 67 134 100

Triclopyr 2 93 104 99

Metolachlor 4 65 125 98

Dichlorprop 2 99 97 98

Prometryn 4 56 108 98

2-Chloro-2’,6’-diethylacetanilide 4 64 115 97

Bentazon 2 89 103 96

Simazine 4 60 106 96

Alachlor 4 59 111 95

MCPA 2 93 97 95

Desulfinyl fipronil 4 67 107 95

Oxamyl 2 79 110 95

Carbaryl1 4 70 107 95

Prometon 4 56 108 94

Diazinon 4 62 102 94

Tebuthiuron1 4 63 111 94

Chlorpyrifos 4 56 101 93

Isofenphos 4 57 109 93

Bendiocarb 2 72 113 92

Acetochlor 4 56 113 92

Cycloate 2 69 111 90

Malaoxon 4 59 97 89

Fonofos 4 54 101 89

Pronamide 4 58 102 89

Malathion 4 57 126 88

Terbufos oxygen analog sulfone 4 62 105 88

Fenamiphos sulfone 4 48 97 87

Ethion monoxon 4 59 104 87

Diazinon oxygen analog 4 56 107 87

Dieldrin, 4 79 102 87

Myclobutanil 4 67 110 86

Terbufos 4 47 91 85

Hexazinone 4 61 100 82

MCPB 2 85 78 82

Table 7B. Quality-control summary of matrix pesticide spike recoveries for samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.

[—, not detected]

Tables 55
Compound Number of

 spike samples

Minimum 

recovery

 (percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Fipronil sulfide 4 66 97 81

2,4-DB 2 85 76 80

2,6-Diethylaniline 4 58 91 80

Azinphos-methyl oxygen analog 4 39 97 80

Methidathion 4 60 91 80

Azinphos-methyl 4 67 96 80

Desulfinylfipronil amide 4 75 97 80

Methyl parathion 4 65 81 79

Fipronil, water 4 60 90 78

Pendimethalin 4 70 93 78

Benomyl 2 68 87 78

Phorate oxygen analog 4 72 95 77

2-Ethyl-6-methylaniline 4 28 88 76

Fonofos oxygen analog 4 49 94 76

Phorate 4 43 85 76

Trifluralin 4 63 97 75

Ethion 4 60 91 73

3-Ketocarbofuran 2 52 91 71

Benfluralin 4 51 91 70

Fenamiphos 4 56 79 66

Metribuzin 4 50 81 66

Fipronil sulfone 4 53 90 65

Methyl paraoxon 4 55 78 64

Iprodione 4 27 70 62

Aldicarb sulfone 2 43 73 58

cis-Permethrin 4 46 75 55

Aldicarb sulfoxide 2 57 54 55

Chlorpyrifos oxygen analog 4 25 76 53

Dichlorvos 4 31 74 52

Deisopropyl atrazine 2 59 42 51

4-Chloro-2-methylphenol 4 38 60 50

Fenamiphos sulfoxide 4 21 90 50

Cyfluthrin 4 45 76 49

Cypermethrin 4 43 72 48

3,4-Dichloroaniline 4 19 80 44

Deethyl atrazine1 4 31 49 42

Dicrotophos 4 15 44 30

Chlorothalonil 2 46 13 29

Table 7B. Quality-control summary of matrix pesticide spike recoveries for samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.

[—, not detected]

56 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Number of

 spike samples

Minimum 

recovery

 (percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Dimethoate 4 17 30 24

Aldicarb 2 31 15 23

Phosmet oxygen analog 4 — 32 20

Phosmet 4 7 29 19

Metsulfuron 2 25 9 17

1-Naphthol 4 10 14 12

1

Compounds on schedule 2003 and 2060; only 2003 values are reported because it is the preferred analytical schedule. 

Table 7B. Quality-control summary of matrix pesticide spike recoveries for samples collected for the San Diego Ground-Water Ambient 

Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.

[—, not detected]

Tables 57
Table 7C. Quality-control summary of matrix waste-water compound spike recoveries for samples collected for the San Diego GroundWater Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

Compound Number of 

spike samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median

 recovery 

(percent)

Caffeine1 1 142 142 na

Tris(2-butoxyethyl) phosphate 2 118 127 123

Tris(dichloroisopropyl) phosphate 2 105 109 107

Carbazole 2 100 109 105

Anthracene, water 2 100 105 102

Triphenyl phosphate 2 100 100 100

Tris(2-chloroethyl) phosphate 2 100 100 100

Phenol 2 95 100 98

Triethyl citrate 2 95 100 98

Fluoranthene 2 91 100 95

Triclosan 2 91 91 91

Phenanthrene 2 86 95 91

Acetophenone 2 86 91 89

3-Methyl-1H-indole 2 86 89 88

p-Cresol 2 85 91 88

Benzophenone 2 85 86 86

4-Nonylphenol 2 85 92 89

4-Cumylphenol, water 2 84 105 94

DEET 2 84 91 87

5-Methyl-1H-benzotriazole 2 82 110 96

Hexahydrohexamethyl cyclopentabenzopyran 2 82 95 89

Tributyl phosphate 2 82 87 85

Isophorone 2 82 86 84

Acetyl hexamethyl tetrahydro naphthalene 2 82 85 83

Isoquinoline 2 82 85 83

Isoborneol, water 2 81 86 84

Camphor 2 80 91 85

Methyl salicylate 2 80 86 83

4-Octylphenol 2 79 95 87

4-tert-Octylphenol 2 78 86 82

Indole 2 77 82 80

Bisphenol A 2 77 79 78

Menthol 2 76 82 79

Pyrene 2 75 86 81

1-Methylnaphthalene 2 73 86 80

2,6-Dimethylnaphthalene 2 73 86 80

2-Methylnaphthalene 2 72 86 79

Cholesterol 2 67 68 67

Benzo[a]pyrene 2 66 91 79

58 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Compound Number of 

spike samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median

 recovery 

(percent)

3-tert-Butyl-4-hydroxyanisole 2 66 68 67

3-beta-Coprostanol 2 64 75 69

Diethoxynonylphenol 2 61 97 79

Diethoxyoctylphenol 2 60 80 70

9,10-Anthraquinone 2 55 78 66

Pentachlorophenol 2 50 74 62

Ethoxyoctylphenol 2 45 80 62

D-Limonene 2 35 86 61

beta-Stigmastanol 2 34 52 43

beta-Sitosterol 2 30 55 42

1

Analyzed on pesticide schedule 2060.

Table 7C. Quality-control summary of matrix waste-water compound spike recoveries for samples collected for the San Diego GroundWater Ambient Monitoring and Assessment (GAMA) study, California, May to July, 2004—Continued.

Table 8. Summary of surrogate compound recoveries for ground-water and quality-control analyses of volatile organic compounds, 

gasoline oxygenates, pesticides and pesticide degradates, and waste-water indicator compound samples collected for the San Diego 

Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

Surrogate Analytical 

schedule Compound class Number of analyses

Number of 

surrogate 

recoveries 

below 70 

percent

Number of 

surrogate 

recoveries 

between 

70 and 130 

percent

Number of 

surrogate 

recoveries 

above 130 

percent

1,2-Dichloroethane-d4 2020 Volatile organic compounds 77 0 72 5

1-Bromo-4-fluorobenzene 2020 Volatile organic compounds 77 0 77 0

Toluene-d8 2020 Volatile organic compounds 77 0 77 0

1,2-Dichloroethane-d4 4024 Gasoline oxygenates 77 0 77 0

1-Bromo-4-fluorobenzene 4024 Gasoline oxygenates 77 0 77 0

Toluene-d8 4024 Gasoline oxygenates 77 0 77 0

Isobutyl alcohol-d6 4024 Gasoline oxygenates 77 7 70 0

alpha-HCH-d6 2003 Pesticides and degradates 72 0 72 0

Diazinon-d10 2003 Pesticides and degradates 72 0 72 0

2,4,5-T 2060 Pesticides and degradates 30 1 29 0

Barban 2060 Pesticides and degradates 30 0 26 4

Caffeine-13C 2060 Pesticides and degradates 30 0 18 12

Bisphenol A-d3 1433 Waste-water indicators 61 24 31 6

Caffeine-13C 1433 Waste-water indicators 61 0 49 12

Decafluorobiphenyl 1433 Waste-water indicators 61 33 28 0

Fluoranthene-d10 1433 Waste-water indicators 25 1 37 11

Tables 59
Table 9. General water-quality parameters determined in the field for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 

2004.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; NTU, nephelometric turbidity unit; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μS/cm, microsiemens per centimeter; C, Celsius; mg/L, milligrams per liter; mm, millimeter; NC, sample not collected; —, not detected]

GAMA

 identification 

No.

Turbidity, 

NTU

(61028)

Barometric 

Pressure, 

mm of mercury

(00025)

Dissolved 

oxygen,

 mg/L 

(00300)

pH, 

standard 

units, 

field

(00400)

Specific 

conductance, 

μS/cm@25C, 

field

(00095)

Total 

hardness, 

mg/L as CaCO3

(00900)

Alkalinity, 

dissolved, as 

CaCO3 mg/L 

(29802)

Bicarbonate, 

dissolved, as 

HCO3 mg/L 

(63786)

Carbonate,

 dissolved, 

as CO3 mg/L 

(63788)

SDTEM-01 0.2 NC 4.8 8.5 439 49 69.2 84

—

SDTEM-02 NC NC NC NC 1,020 NC NC NC NCSDTEM-03 NC NC NC NC 392 NC NC NC NCSDTEM-04 NC NC NC NC 1,020 NC NC NC NCSDTEM-05 1.2 NC 5.0 7.3 648 173 160 194 1SDTEM-06 0.3 735 4.4 7.2 807 316 194 239

—

SDTEM-07 NC NC NC NC 1,260 NC NC NC NCSDTEM-08 NC NC NC NC 920 NC NC NC NCSDTEM-09 NC NC NC NC 510 NC NC NC NCSDTEM-10 NC 727 3.5 7.5 858 261 141 172

—

SDTEM-11 NC NC NC NC 431 NC NC NC NCSDTEM-12

— 722 4.2 7.4 870 208 165 201 1

SDTEM-13

— 730 0.9 8.3 975 78 68 81 1

SDTEM-14

— 733 0.2 8.3 737 96 154 185 2

SDTEMFP-01 0.3 735 4.6 8.1 704 77 116 142 2SDTEMFP-02 0.3 NC 2.1 7.9 818 102 144 172 2SDTEMFP-03 0.3 730 2.3 8.9 807 11 150 166 9SDTEMFP-04 0.3 NC 4.5 7.5 845 243 113 132

—

SDTEMFP-05 NC NC NC NC 1,380 NC NC NC NCSDWARN-01 NC NC NC NC 773 NC NC NC NCSDWARN-02 NC NC NC NC 535 NC NC NC NCSDWARN-03 NC NC NC NC 565 NC NC NC NC

60 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification 

No.

Turbidity, 

NTU

(61028)

Barometric 

Pressure, 

mm of mercury

(00025)

Dissolved 

oxygen,

 mg/L 

(00300)

pH, 

standard 

units, 

field

(00400)

Specific 

conductance, 

μS/cm@25C, 

field

(00095)

Total 

hardness, 

mg/L as CaCO3

(00900)

Alkalinity, 

dissolved, as 

CaCO3 mg/L 

(29802)

Bicarbonate, 

dissolved, as 

HCO3 mg/L 

(63786)

Carbonate,

 dissolved, 

as CO3 mg/L 

(63788)

SDWARN-04 — 690 1.1 8.9 496 65 123 139 5SDWARN-05 — NC 2.2 7.6 502 111 140 170 1SDWARN-06 0.1 686 4.9 7.7 441 86 115 141 1SDWARN-07 NC NC NC NC 555 NC NC NC NCSDWARN-08 NC NC NC NC 371 NC NC NC NCSDWARN-09 NC NC NC NC 382 NC NC NC NCSDALLV-01 0.3 744 5.5 6.9 1,190 466 133 162 —SDALLV-02 0.3 758 3.4 6.8 1,370 552 300 365 —SDALLV-03 0.1 758 0.1 7.5 2,130 418 221 267 1SDALLV-04 NC NC NC NC 911 NC NC NC NCSDALLV-05 NC NC NC NC 978 NC NC NC NCSDALLV-06 .1 758 0.1 7.0 2,787 922 262 319 —SDALLV-07 NC NC NC NC 806 NC NC NC NCSDALLV-08 NC NC NC NC 1,060 NC NC NC NCSDALLV-09 .2 759 0.1 7.6 1,240 201 197 239 1SDALLV-10 NC NC NC NC 2,530 NC NC NC NCSDALLV-11 NC NC NC NC 2,070 NC NC NC NCSDALLV-12 NC NC NC NC 1,310 NC NC NC NCSDALLV-13 .1 762 0.1 7.2 1,300 364 210 255 —SDALLV-14 NC NC NC NC 1,290 NC NC NC NCSDALLV-15 NC NC NC NC 805 NC NC NC NCSDALLV-16 NC NC NC NC 1,320 NC NC NC NCSDALLV-17 NC NC NC NC 836 NC NC NC NCSDHDRK-01 NC NC NC NC 2,280 NC NC NC NC

Table 9. General water-quality parameters determined in the field for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July, 2004—Continued.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; NTU, nephelometric turbidity unit; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μS/cm, microsiemens per centimeter; C, Celsius; mg/L, milligrams per liter; mm, millimeter; NC, sample not collected; —, not detected]

Tables 61
GAMA

 identification 

No.

Turbidity, 

NTU

(61028)

Barometric 

Pressure, 

mm of mercury

(00025)

Dissolved 

oxygen,

 mg/L 

(00300)

pH, 

standard 

units, 

field

(00400)

Specific 

conductance, 

μS/cm@25C, 

field

(00095)

Total 

hardness, 

mg/L as CaCO3

(00900)

Alkalinity, 

dissolved, as 

CaCO3 mg/L 

(29802)

Bicarbonate, 

dissolved, as 

HCO3 mg/L 

(63786)

Carbonate,

 dissolved, 

as CO3 mg/L 

(63788)

SDHDRK-02 NC NC NC NC 712 NC NC NC NCSDHDRK-03 NC NC NC NC 1,290 NC NC NC NCSDHDRK-04 2 645 1.2 7.0 214 71 88.0 107

—

SDHDRK-05 0.1 751 1.8 7.0 1,810 570 266 320

—

SDHDRK-06 0.1 750 0.2 7.3 485 165 144 175

—

SDHDRK-07 0.5 662.5 0.3 7.6 238 74 92.0 112

—

SDHDRK-08 NC NC NC NC 1,240 NC NC NC NCSDHDRK-09 NC NC NC NC 568 NC NC NC NCSDHDRK-10 NC NC NC NC 587 NC NC NC NCSDHDRK-11 NC NC NC NC 919 NC NC NC NCSDHDRK-12 NC NC NC NC 209 NC NC NC NCSDHDRK-13 NC NC NC NC 844 NC NC NC NC

Table 9. General water-quality parameters determined in the field for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; NTU, nephelometric turbidity unit; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μS/cm, microsiemens per centimeter; C, Celsius; mg/L, milligrams per liter; mm, millimeter; NC, sample not collected; —, not detected]

62 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Tables 63

Table 10. Analysis for volatile organic compounds (VOCs) and gasoline oxygenates in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.[Bold, astericked numbers indicate VOCs detected at concentrations above the maximum contaminant level (MCL); percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; mg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

GAMA

 identification

No.

Trihalomethane Solvent

Chloroform 

(trichloromethane) 

(μg/L) 

(32106)

Bromodichloromethane 

(μg/L) 

(32101)

Dibromochloromethane 

(μg/L)

(32105)

Bromoform 

(tribromomethane) 

(μg/L)

(32104)

Tetrachloroethylene

(PCE)

 (μg/L) 

(34475)

cis-1,2-

Dichloroethylene 

(μg/L)

(77093)

Trichloroethylene 

(TCE) 

(μg/L) 

(39180)

1,1,1-Trichloroethane 

(TCA)

 (μg/L) 

(34506)

 Dichloromethane 

(methylene 

chloride) 

(μg/L) 

(34423)

1,2-Dichloroethane

 (μg/L)

(32103)

(LRL) 0.02 0.03 0.1 0.1 0.06 0.02 0.04 0.03 0.1 0.1

SDTEM-01 E0.01 — — — — — — — — —SDTEM-02 — — — — — — — — — —SDTEM-03 E0.02 — — — — — — — — —SDTEM-05 E0.03 — — — E0.02 — — — — —SDTEM-07 0.13 E0.02 — — E0.02 — — — — —SDTEM-10 0.49 0.11 — — — — — — NQ —SDTEM-14 — — — — — — 0.14 — — —SDTEMFP-01 — — — — E0.01 — — — — —SDTEMFP-02 0.11 E0.09 — — — — — — — —SDTEMFP-03 E0.02 — — — — — — — — —SDTEMFP-04 0.48 0.13 — — — — — — — —SDTEMFP-05 — — — — — — — — — —SDWARN-09 — — — — — — — — — —SDALLV-02 E0.06 E0.06 — — — — — E0.02 — —SDALLV-04 — — — — — — — E0.02 — —SDALLV-05 0.39 0.11 — — — — — — — —SDALLV-06 — — — — — E0.03 — — — —SDALLV-07 E0.02 — — — — — — — — —SDALLV-09 E0.05 — — — — — — — — —SDALLV-11 0.20 — — — 0.37 — E0.03 — — —
GAMA

 identification

No.

Solvent Gasoline Organic synthesis

Detections 

per well

Tetrachloromethane 

(carbon tetrachloride) 

(μg/L)

(32102)

1,2-Dichloropropane 

(μg/L)

(34541)

Methyl tertbutyl ether 

(MTBE)

 (μg/L) 

(78032)

Toluene 

(μg/L)

(34010)

Diisopropyl 

ether 

(μg/L)

(81577)

Benzene 

(μg/L)

(34030)

1,1-Dichloroethylene 

(DCE)

(μg/L) 

(34501)

Carbon 

disulfide

 (μg/L) 

(77041)

(LRL) 0.06 0.03 0.2 0.05 0.1 0.02 0.02 0.04

SDTEM-01

—

—

—

—

—

—

—

— 1

SDTEM-02

—

— 0.2

—

— E0.02

—

— 2

SDTEM-03

—

—

—

—

—

—

—

— 1

SDTEM-05

—

—

— E0.01

—

—

—

— 3

SDTEM-07

—

— E0.1

—

—

—

—

— 4

SDTEM-10

—

—

—

—

—

—

—

— 3

SDTEM-14

—

—

—

—

—

—

—

— 1

SDTEMFP-01

—

—

— 0.01

—

—

—

— 2

SDTEMFP-02

—

—

— 0.01

—

—

—

— 3

SDTEMFP-03

—

—

—

—

—

—

—

— 1

SDTEMFP-04

—

—

—

—

—

—

—

— 2

SDTEMFP-05

—

— NQ

—

—

—

—

— 1

SDWARN-09

—

— 0.8

—

—

—

—

— 1

SDALLV-02

—

—

— E0.01

—

—

—

— 4

SDALLV-04

—

—

—

—

—

—

—

— 1

SDALLV-05

—

—

—

—

—

—

—

— 2

SDALLV-06

— 1.19

—

—

—

—

—

— 2

SDALLV-07

—

—

—

—

—

—

—

— 1

SDALLV-09

—

—

—

—

—

—

—

— 1

SDALLV-11 E0.02

— 28.3* —

—

— E0.03

— 6

Table 10. Analysis for volatile organic compounds (VOCs) and gasoline oxygenates in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Bold, astericked numbers indicate VOCs detected at concentrations above the maximum contaminant level (MCL); percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

64 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Tables 65

GAMA

 identification

No.

Trihalomethane Solvent

Chloroform 

(trichloromethane) 

(μg/L) 

(32106)

Bromodichloromethane 

(μg/L) 

(32101)

Dibromochloromethane 

(μg/L)

(32105)

Bromoform 

(tribromomethane) 

(μg/L)

(32104)

Tetrachloroethylene

(PCE)

 (μg/L) 

(34475)

cis-1,2-

Dichloroethylene 

(μg/L)

(77093)

Trichloroethylene 

(TCE) 

(μg/L) 

(39180)

1,1,1-Trichloroethane 

(TCA)

 (μg/L) 

(34506)

 Dichloromethane 

(methylene 

chloride) 

(μg/L) 

(34423)

1,2-Dichloroethane

 (μg/L)

(32103)

(LRL) 0.02 0.03 0.1 0.1 0.06 0.02 0.04 0.03 0.1 0.1

SDALLV-12 — — — — — — — — — —SDALLV-13 — — — — — 0.11 — — — —SDALLV-16 E0.03 E0.05 0.1 — — — — — — —SDALLV-17 — — — — — — — — — —SDHDRK-01 0.27 — — — 9.75* 1.08 7.27* — — 0.3SDHDRK-03 E0.05 — — — — — — — — —SDHDRK-05 E0.01 — — — — — — — — —SDHDRK-13 0.69 3 9.3 7.9 — — — — — —Wells with VOC

 detections

18 8 2 1 5 3 3 2 1 1

Detection 

frequency (percent)

31 14 3 2 9 5 5 3 2 2

Table 10. Analysis for volatile organic compounds (VOCs) and gasoline oxygenates in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Bold, astericked numbers indicate VOCs detected at concentrations above the maximum contaminant level (MCL); percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]
GAMA

 identification

No.

Solvent Gasoline Organic synthesis

Detections 

per well

Tetrachloromethane 

(carbon tetrachloride) 

(μg/L)

(32102)

1,2-Dichloropropane 

(μg/L)

(34541)

Methyl tertbutyl ether 

(MTBE)

 (μg/L) 

(78032)

Toluene 

(μg/L)

(34010)

Diisopropyl 

ether 

(μg/L)

(81577)

Benzene 

(μg/L)

(34030)

1,1-Di-chloroethylene 

(DCE)

(μg/L) 

(34501)

Carbon 

disulfide

 (μg/L) 

(77041)

(LRL) 0.06 0.03 0.2 0.05 0.1 0.02 0.02 0.04

SDALLV-12

—

— E0.1

—

—

—

—

— 1

SDALLV-13

—

—

—

—

—

—

—

— 1

SDALLV-16

—

—

—

—

—

—

—

— 3

SDALLV-17

—

—

—

—

—

—

— 0.26 1

SDHDRK-01

—

— 0.8

— 0.1

— E0.08

— 8

SDHDRK-03

—

—

—

—

—

—

—

— 1

SDHDRK-05

—

—

—

—

—

—

—

— 1

SDHDRK-13

—

—

—

—

—

—

—

— 4

Wells with VOC 

detections

1 1 7 4 1 1 2 1

Detection 

frequency (percent)

2 2 12 7 2 2 3 2

Table 10. Analysis for volatile organic compounds (VOCs) and gasoline oxygenates in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July, 2004—Continued.[Bold, astericked numbers indicate VOCs detected at concentrations above the maximum contaminant level (MCL); percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

66 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA 

identification

No.

Herbicide

Simazine 

(μg/L)

(04035)

Prometon 

(μg/L)

(04037)

Atrazine 

(μg/L)

(39632)

Tebuthiuron

(μg/L)

(82670)

Metolachlor

 (μg/L)

(39415)

Bentazon1

(μg/L)

(38711)

Bromacil1

(μg/L)

(04029)

Diuron1

(μg/L)

(49300)

Imazethapyr1

(μg/L)

(50407)

Acetochlor 

(μg/L)

(49260)

Hexazinone 

(μg/L)

(04025)

Prometryn 

(μg/L)

(04036)

(LRL) 0.005 0.01 0.007 0.02 0.013 0.01 0.03 0.01 0.02 0.006 0.013 0.005

SDTEM-01 0.005 — — — — — — — — — — —SDTEM-02 0.015 0.01 E0.005 — — — — — — — — —SDTEM-03 0.006 — — — — — — — — — — —SDTEM-05 — — E0.003 — E0.002 — — — — E0.002 — —SDTEM-06 0.006 — 0.025 — — — E0.02 — — — — —SDTEM-07 0.011 0.01 0.008 — — — — — — — — —SDTEM-10 0.017 0.01 0.007 — — — — — — — E0.01 0.008SDTEM-12 0.012 — — — — — — — — — — —SDTEM-13 0.010 — E0.006 — — — — — — — — —SDTEMFP-01 0.006 — — — — — — — — — — —SDTEMFP-02 0.006 — — — — — — — — — — —SDTEMFP-04 0.007 — — — — — — — — — — —SDTEMFP-05 0.009 0.01 — — — — — — — — — —SDWARN-03 0.007 — — — — — — — — — — —SDWARN-04 — — — — — — — — — — — —SDWARN-07 0.007 — — — — — — — — — — —SDALLV-01 0.018 — — — E0.01 — — — — — — —SDALLV-02 0.012 — — — — — — — — — — —SDALLV-06 — — — — — E0.01 — — E0.07 — — —

Table 11. Analysis for pesticides in ground-water samples collected for the San Diego Ground-Water Monitoring and Assessment (GAMA) study, California, May to July 2004. [Percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; DHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

Tables 67
GAMA

identification

No.

Herbicide Pesticide degradates Fungicide

Detections 

per well

Terbuthylazine 

(μg/L)

(04022)

Deethylatrazine

 (μg/L)

(04040)

3,4-Dichloroaniline

(μg/L)

(61625)

Deethyldeisopropylatrazine 

(μg/L)

(04039)

Deisopropyl 

atrazine 

(μg/L) 

(04038)

Hydroxyatrazine 

(μg/L)

(50355)

Metalaxyl 

(μg/L)

(61596)

Myclobutanil

 (μg/L)

(61599)

Desulfinyl 

fipronil 

(μg/L)

(62170)

(LRL) 0.01 0.006 0.004 0.04 0.01 0.008 0.005 0.008 0.012

SDTEM-01

—

—

—

— NQ

—

—

—

— 1

SDTEM-02

—

— 0.009

—

—

—

—

—

— 4

SDTEM-03

—

—

—

—

—

—

—

—

— 1

SDTEM-05

—

—

—

—

—

—

—

—

— 3

SDTEM-06

— E0.015

—

—

— E0.011 0.011

—

— 6

SDTEM-07

— E0.007 E0.003

—

—

— 0.011 E0.005 E0.007 8

SDTEM-10 E0.01 E0.005 0.009

—

—

—

—

—

— 8

SDTEM-12

—

—

— E0.02

—

—

—

—

— 2

SDTEM-13

— E0.004

—

—

—

—

—

—

— 3

SDTEMFP-01

—

—

—

—

—

—

—

—

— 1

SDTEMFP-02

—

—

—

—

—

—

—

—

— 1

SDTEMFP-04

— E0.006

—

—

—

—

—

—

— 2

SDTEMFP-05

—

—

—

—

—

—

—

—

— 2

SDWARN-03

—

—

—

—

—

—

—

—

— 1

SDWARN-04

— E0.004

—

—

—

—

—

—

— 1

SDWARN-07

—

—

—

—

—

—

—

—

— 1

SDALLV-01

—

—

— E0.01 E0.03

—

—

—

— 4

SDALLV-02

— E0.001

—

—

—

—

—

—

— 2

SDALLV-06

—

—

—

—

—

—

—

—

— 2

Table 11. Analysis for pesticides in ground-water samples collected for the San Diego Ground-Water Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued. [Percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; DHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

68 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA 

identification

No.

Herbicide

Simazine 

(μg/L)

(04035)

Prometon 

(μg/L)

(04037)

Atrazine 

(μg/L)

(39632)

Tebuthiuron

(μg/L)

(82670)

Metolachlor

 (μg/L)

(39415)

Bentazon1

(μg/L)

(38711)

Bromacil1

(μg/L)

(04029)

Diuron1

(μg/L)

(49300)

Imazethapyr1

(μg/L)

(50407)

Acetochlor 

(μg/L)

(49260)

Hexazinone 

(μg/L)

(04025)

Prometryn 

(μg/L)

(04036)

(LRL) 0.005 0.01 0.007 0.02 0.013 0.01 0.03 0.01 0.02 0.006 0.013 0.005

SDALLV-07 0.008 — — — — — — — — — — —SDALLV-08 0.009 — — — — — — — — — — —SDALLV-10 0.022 0.01 — — E0.008 — — — — — — —SDALLV-11 0.022 0.02 E0.007 E0.09 — — — — — — — —SDALLV-12 0.007 0.01 0.006 E0.02 — — — — — — — —SDALLV-13 — — — — — — — 0.06 — — — —SDALLV-16 0.181 0.01 — — — — — — — — — —SDHDRK-01 0.027 0.01 0.085 E0.03 — — — — — — — —SDHDRK-02 — — — — — — — — — — — —SDHDRK-03 0.007 0.03 — — — — — — — — — —SDHDRK-05 0.007 — — — — — — — — — — —SDHDRK-08 — — — E0.23 — — — — — — — —SDHDRK-09 0.006 — — — — — — — — — — —SDHDRK-13 0.032 — — — — — — — — — — —Detections per 

compound

27 10 9 4 3 1 1 1 1 1 1 1

Detection 

frequency (percent)

47 17 16 7 5 4 4 4 4 2 2 2

Table 11. Analysis for pesticides in ground-water samples collected for the San Diego Ground-Water Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued. [Percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; DHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

Tables 69
GAMA

identification

No.

Herbicide Pesticide degradates Fungicide

Detections 

per well

Terbuthylazine 

(μg/L)

(04022)

Deethylatrazine

 (μg/L)

(04040)

3,4-Dichloroaniline

(μg/L)

(61625)

Deethyldeisopropylatrazine 

(μg/L)

(04039)

Deisopropyl 

atrazine 

(μg/L) 

(04038)

Hydroxyatrazine 

(μg/L)

(50355)

Metalaxyl 

(μg/L)

(61596)

Myclobutanil

 (μg/L)

(61599)

Desulfinyl 

fipronil 

(μg/L)

(62170)

(LRL) 0.01 0.006 0.004 0.04 0.01 0.008 0.005 0.008 0.012

SDALLV-07

— E0.006

—

—

—

—

—

—

— 2

SDALLV-08

—

—

—

—

—

—

—

—

— 1

SDALLV-10

—

—

—

—

—

— 0.009 E0.006

— 5

SDALLV-11

— E0.006

—

—

—

—

— 0.013

— 6

SDALLV-12

— 0.006

—

—

—

—

—

—

— 5

SDALLV-13

—

— 0.013

—

— E0.024

—

—

— 3

SDALLV-16

—

—

—

—

—

—

—

—

— 2

SDHDRK-01

— E0.013

—

—

—

—

—

—

— 5

SDHDRK-02

— E0.006

—

—

—

—

—

—

— 1

SDHDRK-03

—

—

—

—

—

—

—

—

— 2

SDHDRK-05

—

—

—

—

—

—

—

—

— 1

SDHDRK-08

— E0.006

—

—

—

—

—

—

— 2

SDHDRK-09

— E0.006

—

—

—

—

—

—

— 2

SDHDRK-13

—

—

—

—

—

—

—

—

— 1

Detections per 

compound

1 14 4 2 2 2 3 3 1

Detection 

frequency (percent)

2 24 7 8 8 8 5 5 2

Table 11. Analysis for pesticides in ground-water samples collected for the San Diego Ground-Water Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued. [Percentage values are detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; DHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

70 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 12. Analysis for waste-water indicator compounds in ground-water samples collected for the San Diego Ground-Water 

Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

[Concentrations preceded by a “V” indicate detections attributed to contamination, and are not included in ground-water quality analysis; percentage values are 

detection frequencies; the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula 

Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard 

rock study area; μg/L, microgram per liter; E, estimated value; NQ, compound identified but not quantified; —, not detected]

GAMA 

identification 

No.

Phenol

(μg/L)

(34466)

Methyl 

salicylate

(μg/L)

(62081)

DEET

(μg/L)

(62082)

Caffeine1

(μg/L)

(50305)

4-tertoctyl

phenol

(μg/L)

(62062)

Triphenyl 

phosphate

(μg/L) 

(62092)

Tris

(2-butoxyethyl) 

phosphate 

(μg/L) 

(62093)

D-Limonene

 (μg/L)

(62073)

Detections

 per well

(LRL) 0.5 0.5 0.5 0.009 1 0.5 0.5 0.5

SDTEM-12 V0.2 — — — — NQ — — 1

SDTEM-13 V0.1 — — — — — — — 0

SDTEM-14 0.4 — — — — — — NQ 2

SDTEMFP-03 V0.3 — — — — — — — 0

SDTEMFP-04 V0.3 — E0.1 0.0361 — — — — 2

SDWARN-03 V0.1 — — — — — — — 0

SDWARN-04 0.4 — — — — — — — 1

SDWARN-05 0.5 E0.1 — — — — — — 2

SDWARN-07 0.5 — — — — — — — 1

SDWARN-09 V0.2 — — — — — — — 0

SDALLV-02 V0.2 — — — — — — — 0

SDALLV-03 1.7 — — — — — — — 1

SDALLV-04 0.8 — — — — — — — 1

SDALLV-06 V0.2 — — — NQ — — — 1

SDALLV-07 V0.3 — — — — — — — 0

SDALLV-08 V0.3 — — — — — — — 0

SDALLV-09 0.5 — — — — — — — 1

SDALLV-10 V0.3 — — — — — — — 0

SDALLV-11 0.5 — — — — — — — 1

SDALLV-12 E0.4 — — — — — — — 1

SDALLV-13 E0.4 — — — — — — — 1

SDALLV-14 V0.3 — — — — — — — 0

SDALLV-15 V0.2 — — — — — — — 0

SDALLV-16 0.6 — — — — — — — 1

SDALLV-17 — — — — — — 7 — 1

SDHDRK-01 V0.2 — — — — — — — 0

SDHDRK-02 0.5 — — — — — — — 1

SDHDRK-03 2.2 — — — — — — — 1

SDHDRK-04 V0.3 — — — — — — — 0

SDHDRK-07 V0.2 — — — — — — — 0

SDHDRK-08 V0.3 — — — — — — — 0

SDHDRK-09 V0.2 NQ — — — — — — 1

SDHDRK-10 0.5 — — — — — — — 1

SDHDRK-13 — — NQ — — — — — 1

Detections per 

compound

14 2 2 1 1 1 1 1

Detection frequency 

(percent)

30 4 4 2 2 2 2 2

1

Caffeine comcentration determined by the preferred analysis method, pesticide analytical schedule 2060.

Tables 71
GAMA

 identification

 No.

Perchlorate1

(mg/L)

1,4-dioxane

 (mg/L)

N-nitrosodimethylamine, 

(NDMA)

(mg/L)

Detections

 per well

(MRL) 0.25, 0.5, 1, 2 2 0.002

SDTEM-01 1.3 — — 1

SDTEM-05 0.96 — — 1

SDTEM-06 <0.25 — — 0

SDTEM-10 0.74 — — 1

SDTEM-12 0.93 — — 1

SDTEM-13 <0.25 — — 0

SDTEM-14 <0.25 — — 0

SDTEMFP-01 1.4 — — 1

SDTEMFP-02 <0.25 — — 0

SDTEMFP-03 0.49 — — 1

SDTEMFP-04 2.2 — — 1

SDWARN-01 <0.25 NC — 0

SDWARN-02 <0.25 NC — 0

SDWARN-03 <0.25 NC — 0

SDWARN-04 <0.25 — — 0

SDWARN-05 0.33 — — 1

SDWARN-06 0.58 — — 1

SDWARN-07 <1 NC — 0

SDWARN-08 <1 NC — 0

SDWARN-09 <1 NC — 0

SDALLV-01 0.99 — — 1

SDALLV-02 <0.5 — — 0

SDALLV-03 <1 — — 0

SDALLV-04 <1 NC — 0

SDALLV-05 4.2 NC — 1

SDALLV-06 <1 — — 0

SDALLV-07 <1 NC — 0

SDALLV-08 <1 NC — 0

SDALLV-09 <0.25 — — 0

SDALLV-10 <2 NC — 0

SDALLV-11 2.5 NC — 1

SDALLV-12 <1 NC — 0

Table 13. Analysis for emerging contaminant compounds perchlorate, 1,4-dioxane, and N-nitrosodimethylamine (NDMA) in groundwater samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 

2004. 

[Bold, italicized numbers indicate perchlorate detections at concentrations above the detection level for the purposes of reporting (DLR); percentage values are 

detection frequencies; MRL, minimun reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, 

Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; NC, sample not collected; <, less than; —, 

not detected]

72 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification

 No.

Perchlorate1

(mg/L)

1,4-dioxane

 (mg/L)

N-nitrosodimethylamine, 

(NDMA)

(mg/L)

Detections

 per well

(MRL) 0.25, 0.5, 1, 2 2 0.002

SDALLV-13 <1 — — 0

SDALLV-14 <1 NC — 0

SDALLV-15 <0.5 NC — 0

SDALLV-16 <0.5 NC — 0

SDALLV-17 <0.5 NC — 0

SDHDRK-01 1.2 NC — 1

SDHDRK-02 1.7 NC — 1

SDHDRK-03 <1 NC — 0

SDHDRK-04 <1 — — 0

SDHDRK-05 <1 — — 0

SDHDRK-06 <0.5 — — 0

SDHDRK-07 <0.5 — — 0

SDHDRK-08 <0.5 NC — 0

SDHDRK-09 <0.5 NC — 0

SDHDRK-10 <0.5 NC — 0

SDHDRK-11 <0.5 NC — 0

SDHDRK-12 <0.5 NC — 0

SDHDRK-13 <0.5 NC — 0

Detections per compound 14 0 0

Detection frequency (percent) 28 0 0

1

Four different MRLs were used for perchlorate analysis; therefore, non-detects were reported as less than the MRL.

Table 13. Analysis for emerging contaminant compounds perchlorate, 1,4-dioxane, and N-nitrosodimethylamine (NDMA) of the groundwater samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 

2004—Continued. 

[Bold, italicized numbers indicate perchlorate detections at concentrations above the detection level for the purposes of reporting (DLR); percentage values 

are detection frequencies; MRL, minimun reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; 

SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; NC, sample not collected; <, 

less than; —, not detected]

Tables 73
Table 14. Analysis for nutrients and dissolved organic carbon in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004. 

[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water 

Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; 

SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; 

mg/L, milligram per liter; E, estimated value; —, not detected]

GAMA

 identification

No.

Ammonia,

 dissolved 

(mg/L as N) 

(00608)

Nitrate plus 

nitrite, 

dissolved

(mg/L as N) 

(00631)

 Nitrite, 

dissolved 

(mg/L as N)

(00613)

 Phosphorus, 

dissolved 

(mg/L as P) 

(00671)

Total nitrogen 

(nitrate + nitrite 

+ ammonia + 

organic-N), 

dissolved 

(62854)

Dissolved 

organic carbon

 (mg/L) 

(00681)

(LRL) 0.04 0.06 0.008 0.006 0.03 0.3

SDTEM-011 — 4.3 — 0.013 4.22 E0.2

SDTEM-051 — 5.8 — 0.052 5.35 1.3

SDTEM-061 — 3.14 E0.006 0.08 3.11 0.5

SDTEM-10 — 0.41 — 0.037 0.47 0.9

SDTEM-12 — 5.47 — 0.019 5.47 0.6

SDTEM-13 — 1.34 — — 1.39 E0.3

SDTEM-14 0.11 — — 0.033 0.15 0.5

SDTEMFP-011 — 3.84 0.028 0.015 3.67 E0.3

SDTEMFP-02 — 0.52 — 0.01 0.54 0.6

SDTEMFP-03 — 1.28 — 0.013 1.31 0.4

SDTEMFP-04 — 0.5 — 0.073 0.53 0.7

SDWARN-04 — 0.68 — 0.048 0.68 E0.3

SDWARN-05 — 0.92 — 0.012 0.93 —

SDWARN-06 — 1.57 — 0.049 1.66 —

SDALLV-011 — 9.14 — 0.021 8.96 0.8

SDALLV-02 — 1.76 — 0.016 1.88 0.8

SDALLV-03 0.06 — — 0.022 0.04 0.9

SDALLV-06 0.18 — — 0.062 0.3 2.1

SDALLV-09 E0.04 E0.04 — 0.008 0.1 0.4

SDALLV-13 0.18 — — 0.092 0.27 2.1

SDHDRK-04 — — — E0.003 — 3.4

SDHDRK-05 — 0.79 — 0.026 0.85 2.1

SDHDRK-06 — — — — — 0.4

SDHDRK-07 E0.03 — — 0.031 0.05 E0.3

1

Total nitrogen in these samples is less than the sum of the filtered nitrogen analytes, but falls within the U.S. Geological Survey National Water Quality 

Laboratory acceptance criterion of a 10 percent relative percent difference.

74 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification

 No.

Total dissolved solids 

(residue on 

evaporation) 

(mg/L)

(70300)

Calcium

dissolved

(mg/L) 

(00915) 

Magnesium, 

dissolved 

(mg/L )

(00925)

Potassium

dissolved

(mg/L) 

(00935) 

Sodium

dissolved

(mg/L) 

(00930) 

Bromide,

 dissolved

 (mg/L)

(71870) 

Chloride

dissolved

(mg/L)

(00940) 

Fluoride,

 dissolved 

(mg/L)

(00950) 

Silica, 

dissolved 

(mg/L)

(00955)

Sulfate, 

dissolved 

(mg/L)

(00945) 

(LRL) 10 0.01 0.008 0.16 0.1 0.02 0.2 0.2 0.04 0.2

SDTEM-01 259 17.1 1.52 1.6 71.3 0.2 62.7 0.3 20.9 13.4SDTEM-05 402 42.3 16.3 1.82 67.6 0.26 71.7 0.6 46.6 28.8SDTEM-06 520 93.5 19.8 1.3 57.1 00.26 57.8 0.3 32.7 115SDTEM-10 540 65 23.7 4.29 76.6 0.14 79.9 0.3 13.1 173SDTEM-12 508 57 15.81 2.2 99.9 0.44 136 0.7 31.9 32.1SDTEM-13 510 26.8 2.46 1.97 156 0.27 208 0.9 16.3 42.2SDTEM-14 407 33.7 2.81 1.31 119 0.31 96.1 0.3 14.3 56.6SDTEMFP-01 423 25.6 3 1.77 116 0.32 86.8 0.8 18.2 61.1SDTEMFP-02 494 25.6 9.08 2.33 127 0.37 98.8 1 22.2 96.6SDTEMFP-03 478 4.17 0.195 0.9 172 0.34 84.8 0.6 14.3 87.1SDTEMFP-04 532 61.9 21.4 5.32 81.7 0.15 80.5 0.5 20.1 165SDWARN-04 325 21 3.02 0.45 83.1 0.17 41.1 1.4 25.3 58.5SDWARN-05 274 37.5 4.2 1.68 63 0.16 34.8 — 23.9 43.8SDWARN-06 282 26.9 4.5 1.64 59.5 0.17 42.6 0.2 25.9 32.8SDALLV-01 822 123 38.4 5.38 68 0.17 113 — 38.9 271SDALLV-02 766 165 33.7 2.51 87.5 0.35 123 0.2 26.1 233SDALLV-03 1,240 95.3 43.6 4.78 295 1.44 472 0.2 19.4 157SDALLV-06 1,800 234 81.6 9.1 248 1.74 540 0.3 28 421SDALLV-09 685 43 22.5 3.55 174 0.77 228 0.4 22.8 61.7SDALLV-13 812 93 31.9 2.99 126 0.35 179 0.5 25.6 188

Table 15. Analysis for major ions and total dissolved solids in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004. [Bold numbers indicate major ion and total dissolved solid concentrations above the recommended secondary maximum contaminant level (SMCL); the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; mg/L, milligram per liter; —, not detected]

Tables 75
GAMA

 identification

 No.

Total dissolved solids 

(residue on 

evaporation) 

(mg/L)

(70300)

Calcium

dissolved

(mg/L) 

(00915) 

Magnesium, 

dissolved 

(mg/L )

(00925)

Potassium

dissolved

(mg/L) 

(00935) 

Sodium

dissolved

(mg/L) 

(00930) 

Bromide,

 dissolved

 (mg/L)

(71870) 

Chloride

dissolved

(mg/L)

(00940) 

Fluoride,

 dissolved 

(mg/L)

(00950) 

Silica, 

dissolved 

(mg/L)

(00955)

Sulfate, 

dissolved 

(mg/L)

(00945) 

(LRL) 10 0.01 0.008 0.16 0.1 0.02 0.2 0.2 0.04 0.2

SDHDRK-04 148 16.2 7.36 3.04 14.5 0.03 6.32

— 37.6 9.4

SDHDRK-05 1,198 118 66.6 5.2 164 0.53 247 0.4 47.2 320SDHDRK-06 311 51.6 8.86 3.03 37.7 0.14 40.7 0.9 35.9 35.7SDHDRK-07 155 19.8 5.95 2.86 18.5 0.04 9.71 0.3 29.8 12

Table 15. Analysis for major ions and total dissolved solids in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued. [Bold numbers indicate major ion and total dissolved solid concentrations above the recommended secondary maximum contaminant level (SMCL); the five-digit number below the compound name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; mg/L, milligram per liter; —, not detected]

76 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification 

No.

Aluminum

 dissolved

(μg/L)

(01106)

Antimony, 

dissolved 

(μg/L) 

(01095)

Arsenic, 

dissolved 

(μg/L) 

(01000)

Barium, 

dissolved 

(μg/L) 

(01005)

Boron, 

dissolved 

(μg/L) 

(01020)

Cadmium, 

dissolved 

(μg/L)

(01025) 

Chromium, 

dissolved 

(μg/L) 

(01030)

Cobalt, 

dissolved 

(μg/L) 

(01035)

Copper, 

dissolved 

(μg/L)

(01040) 

(LRL) 2 0.2 0.2 0.2 8 0.04 0.8 0.014 0.4

SDTEM-01 2 — 3.4 59 122 — 3 0.038 V0.8

SDTEM-05 — — 1.3 79 41 E0.03 6 0.112 V0.8

SDTEM-06 — — .9 93 68 — 4.4 0.293 1.7

SDTEM-10 — E0.11 .5 35 159 E0.02 — 0.2 4.9

SDTEM-12 2 — 3.1 147 218 — E0.8 0.175 2.4

SDTEM-13 3 — 2.7 134 1054 — 1.1 0.073 V0.5

SDTEM-14 4 — 1.9 125 143 — — 0.127 V0.5

SDTEMFP-01 5 — 7.8 63 299 — 1.6 0.069 V0.9

SDTEMFP-02 4 — 3.1 53 726 0.05 E0.6 0.066 V1.1

SDTEMFP-03 3 — .9 3 — — 1 0.027 V0.4

SDTEMFP-04 — — .9 34 105 E0.03 — 0.151 2.4

SDWARN-04 19 — 7.4 45 361 — E0.4 0.06 V0.5

SDWARN-05 E1 — 1.8 48 42 — — 0.104 V0.8

SDWARN-06 2 — 2.3 46 36 — 1.4 0.085 V0.6

SDALLV-01 — — 1.6 87 51 0.05 — 0.382 6.9

SDALLV-02 3 E0.11 0.9 79 107 0.14 — 0.546 5.8

SDALLV-03 E1 — 2 52 228 E0.02 — 0.317 1.3

SDALLV-06 — — .9 144 161 — — 0.68 2.1

SDALLV-09 E1 — .5 21 214 — — 0.134 V0.5

SDALLV-13 — — 1.7 118 171 — — 0.358 V1.2

SDHDRK-04 — — E0.1 2 E6 — — 0.059 V0.2

SDHDRK-05 — 0.69 5.7 17 158 0.07 — 0.976 13.2

SDHDRK-06 — — .3 8 65 — — 0.198 V0.4

SDHDRK-07 — — .4 139 24 — — 0.071 V0.8

Table 16. Analysis for trace elements in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004. 

[Beryllium and mercury were not detected in any samples; concentrations preceded by a “V” indicate detections attributed to contamination, and are not 

counted in ground-water quality analysis; numbers in bold indicate concentrations that exceed secondary maximum contaminant levels (SMCL); bold italics 

indicate concentrations that exceed detection levels for the purposes of reporting (DLR); the five-digit number below the compound name, the data parameter 

code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent 

or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner 

Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; —, not detected]

Tables 77
GAMA

 identification 

No.

Iron,

 dissolved 

(μg/L) 

(01046)

Lead, 

dissolved 

(μg/L) 

(01049)

Lithium, 

dissolved 

(μg/L) 

(01130)

Manganese, 

dissolved 

(μg/L) 

(01056)

Molybdenum, dissolved 

(μg/L)

(01060) 

Nickel, 

dissolved 

(μg/L) 

(01065)

Selenium, 

dissolved 

(μg/L) 

(01145)

Silver, 

dissolved 

(μg/L) 

(01075)

(LRL) 6 0.08 0.6 0.2 0.4 0.06 0.4 0.2

SDTEM-01 — 0.16 2.2 — 1.9 0.17 0.5 —

SDTEM-05 — 0.09 14.8 0.2 6.2 0.39 2.1 —

SDTEM-06 — 0.28 4.9 — 1.6 1.56 2.1 —

SDTEM-10 — 0.94 17.4 0.3 4.1 1.33 1.3 —

SDTEM-12 E5 0.21 1.3 E0.1 3.8 0.75 0.7 —

SDTEM-13 E4 E0.07 5.2 E0.1 4 0.25 1.2 —

SDTEM-14 11 0.35 3.9 8.9 10 0.33 .5 —

SDTEMFP-01 E6 0.11 4.2 — 2 0.55 1.8 —

SDTEMFP-02 — 0.15 4.1 E0.2 4.6 0.53 1 —

SDTEMFP-03 E4 — 0.6 0.7 1.6 0.14 E0.3 —

SDTEMFP-04 — 0.12 3.5 — 8 0.4 1.1 —

SDWARN-04 — 0.4 3.4 — 7.6 0.29 0.5 —

SDWARN-05 E4 0.09 18 0.3 0.5 0.92 0.7 —

SDWARN-06 — — 15.4 E0.1 1.2 0.29 0.5 —

SDALLV-01 E4 0.29 3.8 0.3 2.5 1.84 30.9 —

SDALLV-02 — 2.7 14.9 E0.1 6.4 2.76 2.1 —

SDALLV-03 37 0.76 18.9 169 11.8 1.19 1.7 —

SDALLV-06 2120 — 3.9 492 10.6 3.44 E0.4 —

SDALLV-09 61 0.4 17.6 14.2 7.2 0.7 1.1 E0.1

SDALLV-13 578 0.08 3.8 362 9.5 2.19 E0.3 —

SDHDRK-04 266 E0.07 11.5 27.8 6.1 0.22 0.4 —

SDHDRK-05 — 0.29 32.1 .6 20.8 3.24 2.7 —

SDHDRK-06 183 0.21 24.6 178 5.3 1.74 0.4 —

SDHDRK-07 — 0.18 10.6 20.5 5.4 0.33 — —

Table 16. Analysis for trace elements in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004—Continued. 

[Beryllium and mercury were not detected in any samples; concentrations preceded by a “V” indicate detections attributed to contamination, and are not counted 

in ground-water quality analysis; numbers in bold indicate concentrations that exceed secondary maximum contaminant levels (SMCL); bold italics indicate concentrations that exceed detection levels for the purposes of reporting (DLR); the five-digit number below the compound name, the data parameter code, is used in 

the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, 

laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; 

SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; —, not detected]

78 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

 identification 

No.

Strontium,

 dissolved

 (μg/L) 

(01080)

Thallium, 

dissolved

(μg/L) 

(01057)

Tungsten, 

dissolved

(μg/L) 

(01155)

Vanadium, 

dissolved 

(μg/L)

(01085) 

Zinc, 

dissolved 

(μg/L) 

(01090)

Uranium, 

dissolved 

(μg/L) 

(22703)

(LRL) 0.4 0.04 0.5 0.7 0.6 0.04

SDTEM-01 127 — 2.7 47.6 V0.3 0.71

SDTEM-05 184 — — 29.9 11.1 1.66

SDTEM-06 396 — — 16.4 1.1 8.75

SDTEM-10 706 — — 3 2.9 2.67

SDTEM-12 443 — 1.2 30.8 2.1 3.62

SDTEM-13 325 — 10 35.3 E0.4 0.83

SDTEM-14 355 — 2.6 1 0.6 0.82

SDTEMFP-01 277 — 13.7 69 E0.6 2.55

SDTEMFP-02 396 — 21 43.4 0.7 3.56

SDTEMFP-03 38.8 — 7.7 V0.3 1.1 0.24

SDTEMFP-04 343 — — 5.8 2.2 1.09

SDWARN-04 121 — 18.0 11.2 1.8 7.94

SDWARN-05 364 — 1.5 11.1 1.4 5.89

SDWARN-06 223 — 1.9 25.9 1.1 2.35

SDALLV-01 409 — — 17 17.8 0.86

SDALLV-02 839 — — 1.8 2.1 7.91

SDALLV-03 740 — — — 29.7 2.9

SDALLV-06 1130 — — 2.1 E1.1 5.2

SDALLV-09 588 — — V0.8 0.7 0.46

SDALLV-13 558 — 0.7 1.1 1 0.95

SDHDRK-04 67.2 — — 1 77.5 0.06

SDHDRK-05 438 E0.04 1.2 25.8 4.7 17.8

SDHDRK-06 109 — 2.9 V0.2 15.7 4.89

SDHDRK-07 110 — 0.8 3.8 11.4 0.26

Table 16. Analysis for trace elements in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004—Continued. 

[Beryllium and mercury were not detected in any samples; concentrations preceded by a “V” indicate detections attributed to contamination, and are not counted 

in ground-water quality analysis; numbers in bold indicate concentrations that exceed secondary maximum contaminant levels (SMCL); bold italics indicate concentrations that exceed detection levels for the purposes of reporting (DLR); the five-digit number below the compound name, the data parameter code, is used in 

the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property; LRL, 

laboratory reporting level; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; 

SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; E, estimated value; —, not detected]

Tables 79
Table 17. Analysis for chromium, arsenic, and iron speciation by the U.S. Geological Survey National Research Progam in ground-water 

samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004.

[Concentrations preceded by a “V” indicate detections attributed to contamination, and are not included in ground-water quality analysis; numbers in bold 

indicate concentrations that exceed secondary maximum contaminant levels (SMCL); bold italics indicate concentrations that exceed detection levels for the 

purposes of reporting (DLR). MDL, method detection limit; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; 

SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; NC, sample not collected or 

ruined before analysis; —, not detected]

GAMA

identification 

No.

Chromium, 

dissolved 

(μg/L)

Chromium (VI), 

(hexavalent)

dissolved 

(μg/L)

Arsenic, 

dissolved 

(μg/L) 

Arsenic (III), 

dissolved 

(μg/L) 

Iron,

 dissolved 

(μg/L) 

Iron (II), 

dissolved 

(μg/L) 

(MDL) 0.1 0.1 0.5 1 1 1

SDTEM-01 3.5 2.7 3.3 — — —

SDTEM-05 5.7 5.6 0.8 — — —

SDTEM-06 4.5 4.7 — — 3 3

SDTEM-10 — — NC NC NC NC

SDTEM-12 0.9 0.8 2.8 — 5 4

SDTEM-13 1.1 1.1 2.2 — 3 2

SDTEM-14 0.7 — 1.6 — 8 3

SDTEMFP-01 2.5 2.6 7.4 — — —

SDTEMFP-02 1.2 — 2.8 — 5 3

SDTEMFP-03 0.9 0.6 3.3 — 2 —

SDTEMFP-04 0.6 0.2 — — — —

SDWARN-01 1.7 1.1 NC NC NC NC

SDWARN-02 0.5 0.6 NC NC NC NC

SDWARN-03 0.7 0.3 NC NC NC NC

SDWARN-04 — 0.6 7.5 — 2 —

SDWARN-05 0.4 0.4 1.5 — 3 2

SDWARN-06 1.1 0.6 1.8 — 3 2

SDWARN-07 0.4 — NC NC NC NC

SDWARN-08 0.7 0.7 NC NC NC NC

SDWARN-09 0.1 0.1 NC NC NC NC

SDALLV-01 2.1 0.3 — — 2 2

SDALLV-02 0.4 0.3 — — 2 2

SDALLV-03 0.2 — 1.6 1.6 33 29

SDALLV-04 1.1 0.4 NC NC NC NC

SDALLV-05 2.0 1.6 NC NC NC NC

SDALLV-06 1.3 0.5 NC NC 1,917 1,913

SDALLV-07 0.5 0.2 NC NC NC NC

SDALLV-08 0.2 0.2 NC NC NC NC

SDALLV-09 — — — — 50 12

SDALLV-10 — V2.6 NC NC NC NC

SDALLV-11 — 0.3 NC NC NC NC

SDALLV-12 0.3 — NC NC NC NC

SDALLV-13 0.3 0.9 1.4 1.4 521 504

SDALLV-14 0.2 0.1 NC NC NC NC

SDALLV-15 0.7 — NC NC NC NC

80 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

identification 

No.

Chromium, 

dissolved 

(μg/L)

Chromium (VI), 

(hexavalent)

dissolved 

(μg/L)

Arsenic, 

dissolved 

(μg/L) 

Arsenic (III), 

dissolved 

(μg/L) 

Iron,

 dissolved 

(μg/L) 

Iron (II), 

dissolved 

(μg/L) 

SDALLV-16 0.3 0.5 NC NC NC NC

SDALLV-17 0.2 — NC NC NC NC

SDHDRK-01 0.6 0.3 NC NC NC NC

SDHDRK-02 1.2 0.8 NC NC NC NC

SDHDRK-03 — — NC NC NC NC

SDHDRK-04 0.5 0.3 — — 235 225

SDHDRK-05 1.2 0.2 4.9 — — —

SDHDRK-06 0.6 0.4 — — 166 161

SDHDRK-07 0.9 0.3 — — 1 —

SDHDRK-08 0.2 0.4 NC NC NC NC

SDHDRK-09 0.3 — NC NC NC NC

SDHDRK-10 0.3 0.3 NC NC NC NC

SDHDRK-11 0.3 0.5 NC NC NC NC

SDHDRK-12 0.1 — NC NC NC NC

SDHDRK-13 0.1 — NC NC NC NC

Table 17. Analysis for chromium, arsenic, and iron speciation by the U.S. Geological Survey National Research Progam in groundwater samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 

2004—Continued.

[Concentrations preceded by a “V” indicate detections attributed to contamination, and are not included in ground-water quality analysis; numbers in bold 

indicate concentrations that exceed secondary maximum contaminant levels (SMCL); bold italics indicate concentrations that exceed detection levels for the 

purposes of reporting (DLR). MDL, method detection limit; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; 

SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; μg/L, microgram per liter; NC, sample not collected or 

ruined before analysis; —, not detected]

Tables 81
Table 18. Analysis for isotopes and radioactivity in ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property. SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; pCi/L, picocuries per liter; NA, not applicable; NC, sample not collected or ruined before analysis; NQ, detected but not quantified;—, not detected]

GAMA

 identification 

No.

Deuterium/

protium 

ratio, 

per mil 

(82082)

Oxygen18/

oxygen-16 

ratio 

(per mil)

(82085)

Radium226 

(pCi/L )

(09511)

Radium228

 (pCi/L) 

(81366)

Radon222 

(pCi/L) 

(82303)

Radon-222 

2-sigma 

combined 

uncertainty 

(pCi/L) 

(76002)

Tritium 

(pCi/L) 

(07000)

Tritium 2-

sigma 

combined 

uncertainty 

(pCi/L)

(75985)

Alpha 

radioactivity, 

72-hour 

count

(pCi/L)

(62636)

Alpha

 radioactivity, 

30-day 

count

(pCi/L) 

(62369)

Beta 

radioactivity,

 72-hour 

count 

(pCi/L) 

(62642)

Beta 

radioactivity,

30-day 

count

 (pCi/L) 

(62645)

Carbon-13/

carbon-12 

(ratio per 

mil)

(NA)

Carbon14

(percent 

modern)

(NA)

SDTEM-01 −48 −7.05 0.05 NQ 250 22 NQ 1 1 NQ 2 2 −16.4* 0.51SDTEM-02 −45 −6.76 NC NC NC NC 4 0.6 NC NC NC NC NC NCSDTEM-03 −50.3 −7.44 NC NC NC NC NQ 1 NC NC NC NC NC NCSDTEM-04 −46 −5.9 NC NC NC NC 11 1 NC NC NC NC NC NCSDTEM-05 −45.5 −6.81 0.03

— 250 22 1 1 2 1 2 2 −20.1* 0.84

SDTEM-06 −42.5 −6.62 0.03 NQ 350 23 5 1 6 6 2 4 −17.7* 0.96SDTEM-07 −45.9 −6.42 NC NC NC NC 10 1 NC NC NC NC NC NCSDTEM-08 −44.9 −6.73 NC NC NC NC 3 0.6 NC NC NC NC NC NCSDTEM-09 −54.3 −8.13 NC NC NC NC

— 0.6 NC NC NC NC NC NC

SDTEM-10 −80.7 −10.02 0.07 NQ 270 22 20 1.3 2 1 4 6 −10.5* 0.91SDTEM-11 −49 −7.15 NC NC NC NC

— 1 NC NC NC NC NC NC

SDTEM-12 −50.7 −7.31 0.08

— 350 22 3 0.6 3 NQ 3 4 −16.4* 0.98

SDTEM-13 −49.2 −7.11 0.06 NQ 230 22 NQ 0.6 2 NQ 2 3 −16.8* 0.58SDTEM-14 −44.9 −6.9 0.05 2 280 22 2 0.6 2 NQ 1 2 −17.3* 0.60SDTEMFP-01 −48.1 −7.02 0.05 NQ 410 25 2 1 3 1 2 2 −16.5* 0.74SDTEMFP-02 −46 −6.4 0.02 NQ 310 23 4 0.6 4 3 2 3 −14.1* 0.70SDTEMFP-03 −46.6 −6.63 0.15 NQ 420 24 2 1 1 NQ NQ 2 −14.2* 0.75SDTEMFP-04 −84.8 −10.5 0.05 NQ 210 28 22 1.3 NQ NQ 5 6 −11.0* 0.92SDTEMFP-05 −46.6 −6.4 NC NC NC NC 9 1 NC NC NC NC NC NCSDWARN-01 −51.4 −7.57 NC NC NC NC NQ 1 NC NC NC NC NC NCSDWARN-02 −55.5 −8.35 NC NC NC NC 6 1 NC NC NC NC NC NC

82 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 18. Analysis for isotopes and radioactivity in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004—Continued.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property. SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; pCi/L, picocuries per liter; NA, not applicable; NC sample not collected or ruined before analysis; NQ, detected but not quantified;—, not detected]

GAMA

 identification 

No.

Deuterium/

protium 

ratio, 

per mil 

(82082)

Oxygen18/

oxygen-16 

ratio 

(per mil)

(82085)

Radium226 

(pCi/L )

(09511)

Radium228

 (pCi/L) 

(81366)

Radon222 

(pCi/L) 

(82303)

Radon-222 

2-sigma 

combined 

uncertainty 

(pCi/L) 

(76002)

Tritium 

(pCi/L) 

(07000)

Tritium 2-

sigma 

combined 

uncertainty 

(pCi/L)

(75985)

Alpha 

radioactivity, 

72-hour 

count

(pCi/L)

(62636)

Alpha

 radioactivity, 

30-day 

count

(pCi/L) 

(62369)

Beta 

radioactivity,

 72-hour 

count 

(pCi/L) 

(62642)

Beta 

radioactivity,

30-day 

count

 (pCi/L) 

(62645)

Carbon-13/

carbon-12 

(ratio per 

mil)

(NA)

Carbon14

(percent 

modern)

(NA)

SDWARN-03 −50.8 −7.36 NC NC NC NC 5 0.6 NC NC NC NC NC NCSDWARN-04 −56.4 −8.4 0.08 NQ 1,120 34 NQ 0.6 3 2 — 3 −16.4* 0.78SDWARN-05 −55.7 −8.4 0.04 NQ 910 31 NQ 0.6 4 2 2 4 −15.4* 0.85SDWARN-06 −57 −8.31 0.09 NQ 780 30 NQ 0.6 2 NQ 2 2 −25.8* 0.81SDWARN-07 −56.3 −8.53 NC NC NC NC 4 0.6 NC NC NC NC NC NCSDWARN-08 −59.7 −9.04 NC NC NC NC 1 0.6 NC NC NC NC NC NCSDWARN-09 −66.6 −9.78 NC NC NC NC NQ 0.6 NC NC NC NC NC NCSDALLV-01 −47.3 −6.77 0.09 — 530 26 10 0.3 2 — 4 7 −16.8 0.99SDALLV-02 −43.4 −6.26 0.16 NQ 1,190 34 11 1 4 4 2 6 −17.64 0.99SDALLV-03 −38.8 −5.98 0.1 NQ 240 21 — 0.6 5 2 6 4 −13.88 0.59SDALLV-04 −37.2 −5.77 NC NC NC NC 5 0.6 NC NC NC NC NC NCSDALLV-05 −45.7 −7.19 NC NC NC NC 13 0.6 NC NC NC NC NC NCSDALLV-06 −41.5 −5.94 0.2 NQ 180 21 19 1.3 9 2 7 11 −15.73 1.01SDALLV-07 −37.1 −5.77 NC NC NC NC 14 1 NC NC NC NC NC NCSDALLV-08 −42.8 −6.26 NC NC NC NC 12 1 NC NC NC NC NC NCSDALLV-09 −36.7 −5.56 0.14 NQ 420 25 — 0.6 3 NQ 3 6 −13.69 0.22SDALLV-10 −49 −6.52 NC NC NC NC 19 1.3 NC NC NC NC NC NCSDALLV-11 −46.9 −6.54 NC NC NC NC 22 1.3 NC NC NC NC NC NCSDALLV-12 −30.6 −4.1 NC NC NC NC 8 0.6 NC NC NC NC NC NCSDALLV-13 −39.2 −5.43 0.13 NQ 180 20 11 1 2 NQ 1 3 −17.74 0.95SDALLV-14 −42 −6.29 NC NC NC NC 6 0.6 NC NC NC NC NC NCSDALLV-15 −46.6 −7.22 NC NC NC NC 7 1 NC NC NC NC NC NC

Tables 83
Table 18. Analysis for isotopes and radioactivity in ground-water samples collected in the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, 

California, May to July 2004—Continued.[The five-digit number below the constituent name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water Information System (NWIS), to uniquely identify a specific constituent or property. SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area; pCi/L, picocuries per liter; NA, not applicable; NC, sample not collected or ruined before analysis; NQ, detected but not quantified;—, not detected]

GAMA

 identification 

No.

Deuterium/

protium 

ratio, 

per mil 

(82082)

Oxygen18/

oxygen-16 

ratio 

(per mil)

(82085)

Radium226 

(pCi/L )

(09511)

Radium228

 (pCi/L) 

(81366)

Radon222 

(pCi/L) 

(82303)

Radon-222 

2-sigma 

combined 

uncertainty 

(pCi/L) 

(76002)

Tritium 

(pCi/L) 

(07000)

Tritium 2-

sigma 

combined 

uncertainty 

(pCi/L)

(75985)

Alpha 

radioactivity, 

72-hour 

count

(pCi/L)

(62636)

Alpha

 radioactivity, 

30-day 

count

(pCi/L) 

(62369)

Beta 

radioactivity,

 72-hour 

count 

(pCi/L) 

(62642)

Beta 

radioactivity,

30-day 

count

 (pCi/L) 

(62645)

Carbon-13/

carbon-12 

(ratio per 

mil)

(NA)

Carbon14

(percent 

modern)

(NA)

SDALLV-16 −52.9 −6.9 NC NC NC NC 16 1.3 NC NC NC NC NC NCSDALLV-17 −56.6 −7.76 NC NC NC NC 7 1 NC NC NC NC NC NCSDHDRK-01 −39.5 −5.7 NC NC NC NC 8 1 NC NC NC NC NC NCSDHDRK-02 −48.7 −7.12 NC NC NC NC 2 0.6 NC NC NC NC NC NCSDHDRK-03 −47.4 −6.81 NC NC NC NC 8 1 NC NC NC NC NC NCSDHDRK-04 −51.9 −8.39 0.04 NQ 1,550 39 6 0.6 NQ 1 3 3 −19.9* 0.97SDHDRK-05 −48 −6.56 0.13 NQ 1,420 37 11 1 8 9 6 10 −15.75 1.02SDHDRK-06 −54.2 −8.25 0.41 NQ 4,820 65 1 0.6 8 6 4 7 −17.73 0.76SDHDRK-07 −49.1 −7.86 0.05

— 550 26 1.2 0.6 NQ NQ 3 2 −22.66 0.64

SDHDRK-08 −49.3 −7.48 NC NC NC NC 5 0.6 NC NC NC NC NC NCSDHDRK-09 −43.3 −6.93 NC NC NC NC 7 1 NC NC NC NC NC NCSDHDRK-10 −45.7 −7.1 NC NC NC NC 9 1 NC NC NC NC NC NCSDHDRK-11 −34.3 −5.05 NC NC NC NC 3 0.6 NC NC NC NC NC NCSDHDRK-12 −53.2 −8.18 NC NC NC NC 2 0.6 NC NC NC NC NC NCSDHDRK-13 −36.8 −5.29 NC NC NC NC 9 1 NC NC NC NC NC NC

*Carbon-13/carbon-12 ratio not used to correct carbon-14 percent modern value for that sample.

84 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 19. Analysis for tritium and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and 

Assessment (GAMA) study, California, May to July 2004.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

SDTEM-01 05/18/04 0.29 0.66 09/19/04 3.008 12.106 2.356 3.500 7.254 0.971

09/23/04 3.046 12.383 2.365 3.464 7.389 0.985

SDTEM-02 05/24/04 NC NC 09/20/04 3.027 20.008 3.671 4.612 9.093 1.196

09/24/04 3.027 20.612 3.816 4.584 9.322 1.212

SDTEM-03 05/24/04 1.13 0.15 09/19/04 2.391 6.840 2.470 3.657 8.007 1.041

09/23/04 2.372 6.922 2.578 3.646 7.999 1.040

SDTEM-04 05/24/04 10.47 0.45 09/20/04 1.546 1.168 3.771 4.626 9.153 1.133

09/23/04 1.535 1.190 3.815 4.650 9.054 1.147

SDTEM-05 05/25/04 — 0.48 09/20/04 0.646 1.770 2.835 3.959 8.026 1.013

09/24/04 0.642 1.786 2.746 3.930 8.178 1.040

SDTEM-06 05/26/04 4.78 0.28 09/20/04 1.315 0.823 2.549 3.792 8.126 1.088

09/24/04 1.313 0.823 2.613 3.786 8.040 1.090

SDTEM-07 05/27/04 9.92 0.44 09/21/04 1.458 0.739 3.024 4.000 8.657 1.114

09/24/04 1.463 0.742 3.025 3.980 8.358 1.114

SDTEM-08 05/27/04 2.90 0.22 09/21/04 3.644 5.370 2.544 3.600 7.889 0.981

10/13/04 3.625 5.624 2.610 3.610 7.713 1.003

SDTEM-09 05/27/04 0.10 0.12 09/20/04 2.082 86.537 2.944 4.176 9.163 1.204

10/12/04 2.044 87.160 2.911 4.203 9.223 1.194

SDTEM-10 05/27/04 20.21 0.88 09/20/04 1.369 1.017 4.053 4.303 8.430 1.106

10/13/04 1.382 1.028 4.148 4.348 9.001 1.122

Tables 85
GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

SDTEM-11 06/16/04 0.13 0.12 09/22/04 1.917 3.526 2.476 3.557 7.614 1.054

09/27/04 1.947 3.526 2.434 3.486 7.479 1.012

SDTEM-12 06/21/04 2.89 0.23 09/22/04 2.526 10.359 2.531 3.654 7.988 1.021

09/28/04 2.526 10.764 2.555 3.621 7.751 1.038

SDTEM-13 06/22/04 0.90 0.16 09/23/04 3.490 87.371 2.287 3.436 7.539 1.003

09/28/04 3.451 88.055 2.266 3.401 7.434 0.978

SDTEM-14 06/23/04 1.98 0.20 09/23/04 3.972 17.712 2.474 3.645 7.757 1.058

09/28/04 3.972 17.996 2.455 3.620 7.749 1.067

SDTEMFP-01 05/19/04 0.89 0.14 09/19/04 2.179 9.281 2.512 3.571 7.737 1.001

09/23/04 2.198 9.732 2.505 3.532 7.442 1.022

SDTEMFP-02 05/20/04 3.82 0.23 09/19/04 2.082 20.665 3.837 4.780 9.571 1.237

09/23/04 2.102 21.145 3.727 4.738 9.978 1.241

SDTEMFP-03 06/14/04 2.83 0.19 09/21/04 1.807 11.772 4.259 4.996 10.238 1.229

09/27/04 1.812 11.841 4.077 4.976 10.073 1.262

SDTEMFP-04 06/15/04 23.52 0.98 09/21/04 1.381 0.681 2.760 3.856 8.367 1.153

09/27/04 1.382 0.682 2.770 3.827 8.275 1.142

SDTEMFP-05 06/16/04 9.49 0.46 09/21/04 1.510 0.935 3.281 4.234 8.837 1.131

09/27/04 1.537 0.854 2.997 4.099 8.897 1.175

SDWARN-01 06/17/04

— 0.21 09/22/04 0.316 3.338 2.748 3.962 8.594 1.122

09/28/04 0.659 14.593 24.044 9.834 22.663 2.134

SDWARN-02 06/17/04 5.69 0.31 09/22/04 1.284 1.511 5.825 6.313 11.459 1.398

09/28/04 1.284 1.845 7.020 6.986 12.630 1.440

Table 19. Analysis for tritium and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

86 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

SDWARN-03 06/17/04 7.03 0.36 09/22/04 1.425 1.047 4.179 4.503 9.014 1.185

09/28/04 1.429 1.076 4.229 4.603 9.332 1.181

SDWARN-04 06/24/04 0.06 0.33 09/23/04 0.115 21.553 4.606 5.374 10.413 1.294

09/28/04 0.118 21.800 4.488 5.396 10.676 1.221

SDWARN-05 06/28/04 0.18 0.14 09/28/04 1.039 1.734 4.955 5.064 10.211 1.284

10/05/04 1.035 1.085 3.206 4.410 9.118 1.199

SDWARN-06 06/29/04 0.18 0.15 09/28/04 1.140 1.266 4.304 5.056 10.274 1.229

10/05/04 1.143 1.266 4.439 5.093 10.034 1.210

SDWARN-07 07/13/04 4.91 0.32 NA NC NC NC NC NC NC

NA NC NC NC NC NC NC

SDWARN-08 07/13/04 0.67 0.15 09/29/04 0.125 24.350 2.410 3.511 8.043 1.113

10/06/04 0.189 52.606 2.481 3.706 8.051 1.137

SDWARN-09 07/13/04 0.13 0.17 09/29/04 0.061 53.498 2.792 3.929 8.628 1.169

10/07/04 0.061 53.891 2.782 3.972 8.555 1.134

SDALLV-01 06/30/04 12.17 0.73 09/29/04 1.313 0.647 2.465 3.550 7.872 1.067

10/05/04 1.315 0.639 2.410 3.568 8.059 1.069

SDALLV-02 07/01/04 13.03 0.58 09/29/04 1.251 0.565 2.276 3.550 7.961 1.027

10/05/04 1.282 0.563 2.278 3.532 7.940 1.090

SDALLV-03 07/12/04 — 0.21 09/29/04 0.212 6.379 2.494 3.790 8.108 1.097

10/06/04 0.206 6.252 2.539 3.779 8.146 1.068

SDALLV-04 07/12/04 7.28 0.36 09/29/04 1.363 0.898 3.179 4.174 8.559 1.076

10/06/04 1.350 0.895 3.236 4.166 8.783 1.064

Table 19. Analysis for tritum and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

Tables 87
GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

SDALLV-05 07/12/04 13.20 0.59 NA NC NC NC NC NC NC

NA NC NC NC NC NC NC

SDALLV-06 07/13/04 19.83 0.82 09/29/04 1.186 3.070 5.448 5.304 10.251 1.201

10/06/04 1.172 1.720 3.517 4.417 8.967 1.109

SDALLV-07 07/14/04 13.74 0.58 09/30/04 1.369 0.722 2.658 3.711 8.198 1.113

10/07/04 1.359 0.722 2.699 3.795 8.238 1.045

SDALLV-08 07/14/04 12.12 0.53 09/30/04 0.883 1.530 3.570 4.352 8.464 1.076

10/07/04 0.883 1.457 3.345 4.270 8.369 1.014

SDALLV-09 07/14/04 0.03 0.11 09/30/04 0.299 2.888 2.133 3.204 7.195 0.931

10/07/04 0.301 3.007 2.209 3.238 7.209 0.947

SDALLV-10 07/14/04 18.55 0.71 09/30/04 1.165 0.738 2.421 3.724 8.238 1.123

10/07/04 1.155 0.740 2.378 3.732 8.456 1.128

SDALLV-11 07/15/04 23.70 0.98 09/30/04 0.856 1.306 2.372 3.518 7.821 1.019

10/07/04 0.854 1.298 2.354 3.500 7.691 1.026

SDALLV-12 07/15/04 8.44 0.37 09/30/04 0.374 3.681 2.410 3.468 7.517 1.015

10/07/04 0.366 3.797 2.467 3.482 7.578 0.990

SDALLV-13 07/15/04 11.25 0.78 09/30/04 0.893 1.492 2.621 3.791 8.414 1.109

10/07/04 0.897 1.492 2.713 3.815 8.071 1.083

SDALLV-14 07/15/04 6.89 0.33 09/30/04 1.116 0.822 2.381 3.750 8.264 1.113

10/08/04 1.107 0.819 2.397 3.771 8.475 1.075

SDALLV-15 07/27/04 6.09 0.30 10/04/04 0.442 1.762 2.150 3.353 7.366 0.977

10/11/04 0.441 1.775 2.149 3.350 7.540 0.985

Table 19. Analysis for tritum and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

88 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

SDALLV-16 07/28/04 15.43 0.65 10/04/04 1.371 0.590 2.460 3.457 7.539 0.968

10/11/04 1.382 0.595 2.455 3.479 7.614 0.979

SDALLV-17 07/29/04 5.87 0.28 10/05/04 0.195 75.546 2.329 3.585 7.825 1.017

10/12/04 0.186 123.926 2.353 3.567 7.772 0.989

SDHDRK-01 07/12/04 3.88 0.29 09/29/04 0.251 4.905 2.570 3.536 7.572 0.976

10/05/04 0.241 4.934 2.589 3.532 7.457 0.976

SDHDRK-02 07/13/04 1.02 0.20 09/29/04 1.473 0.608 2.528 3.807 8.341 1.117

10/07/04 1.483 0.609 2.563 3.868 8.227 1.093

SDHDRK-03 07/15/04 9.58 0.45 09/30/04 0.536 1.938 2.815 3.802 7.953 1.021

10/08/04 0.534 1.899 2.789 3.760 8.136 0.986

SDHDRK-04 07/19/04 5.52 0.52 10/01/04 1.531 0.681 2.636 4.053 8.967 1.216

10/08/04 1.548 0.670 2.581 4.055 9.105 1.139

SDHDRK-05 07/20/04 11.17 0.48 10/01/04 0.474 1.928 2.737 3.775 8.031 1.056

10/08/04 0.526 2.058 3.214 4.001 8.208 1.031

SDHDRK-06 07/21/04 1.30 0.15 10/01/04 0.307 23.379 3.054 4.204 8.999 1.158

10/10/04 0.312 22.757 3.129 4.199 9.078 1.162

SDHDRK-07 07/22/04 1.20 0.15 10/03/04 0.781 0.932 2.250 3.614 8.095 1.049

10/11/04 0.792 0.943 2.246 3.632 8.227 1.070

SDHDRK-08 07/27/04 6.13 0.34 10/03/04 0.237 13.125 3.348 4.041 8.608 1.098

10/11/04 0.488 2.277 2.507 3.479 7.812 1.062

SDHDRK-09 07/27/04 6.16 0.31 10/03/04 0.989 0.682 1.973 3.307 7.571 1.022SDHDRK-10 07/28/04 8.98 0.40 10/04/04 1.076 0.817 2.863 3.746 8.212 1.070

Table 19. Analysis for tritum and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

Tables 89
GAMA

identification 

No.

Collection 

date

Tritium

(pCi/L)

Tritium 2-

sigma, 

combined

 uncertainty 

(pCi/L

Dissolved 

gas

 analysis 

date

Helium-3/

Helium-4

(atom ratio)

Helium-4

(cm3STP/g)

Neon

(cm3STP/g)

Argon

(cm3STP/g)

Krypton

(cm3STP/g)

Xenon

(cm3STP/g)

x 10-6 x 10-7 x 10-7 x 10-4 x 10-8 x 10-8

10/11/04 1.072 0.809 2.650 3.757 8.311 1.064

SDHDRK-11 07/28/04 3.64 0.22 10/04/04 0.233 4.819 2.873 3.696 7.803 0.988

10/11/04 0.229 4.823 2.910 3.689 7.683 1.023

SDHDRK-12 07/29/04 1.62 0.13 10/05/04 1.253 0.907 3.441 4.614 9.897 1.200

10/12/04 1.251 0.915 3.447 4.615 9.747 1.184

SDHDRK-13 07/29/04 8.62 0.43 10/05/04 1.014 0.693 2.206 3.350 7.691 1.016

10/11/04 1.016 0.643 2.102 3.300 7.706 1.011

Table 19. Analysis for tritum and noble gases done at Lawrence Livermore National Laboratory in samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment (GAMA) study, California, May to July 2004—Continued.[Duplicate noble gas analyses are shown for each sample; SDTEM, Temecula Valley study area; SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area. NA, not available; NC, sample not collected or ruined before analysis; —, not detected]

90 California GAMA Program: Ground-Water Quality Data, San Diego Drainages Hydrogeologic Province, California, 2004
Table 20. Microbial analysis of ground-water samples collected for the San Diego Ground-Water Ambient Monitoring and Assessment 

(GAMA) study, California, May to July 2004.

[The five-digit number below the microbe name, the data parameter code, is used in the U.S. Geological Survey computerized data system, National Water 

Information System (NWIS), to uniquely identify a specific constituent or property; LRL, laboratory reporting level; SDTEM, Temecula Valley study area; 

SDTEMFP, Temecula Valley study area flow-path well; SDWARN, Warner Valley study area; SDALLV alluvial study area; SDHDRK, hard rock study area;

mL, milliliter; NQ, microbial constiuent identified but not quantified; —, not detected]

GAMA

 identification 

No.

Coliphage, 

F-specific

(99335)

Coliphage, 

somatic

(99332)

E. coli, 

colonies/100mL

(90901)

Total coliforms, 

colonies/100mL

(90900)

SDTEM-01 — — — —

SDTEM-05 — — — —

SDTEM-06 — — — —

SDTEM-10 — — — —

SDTEM-12 — — — —

SDTEM-13 — NQ — —

SDTEM-14 — — — —

SDTEMFP-01 — — — —

SDTEMFP-02 — — — —

SDTEMFP-03 — — — —

SDTEMFP-04 — — — —

SDWARN-04 — NQ — —

SDWARN-05 — — — —

SDWARN-06 — — — —

SDALLV-01 — — — —

SDALLV-02 — — — —

SDALLV-03 — — — —

SDALLV-06 — — — —

SDALLV-09 — — — —

SDALLV-13 NQ — — —

SDHDRK-04 — — — —

SDHDRK-05 — — — —

SDHDRK-06 — — — —

SDHDRK-07 — — — —

Tables 91