In cooperation with the California State Water Resources Control Board

Ground-Water Quality Data in the Southern Sierra Study 

Unit, 2006—Results from the California GAMA Program

U.S. Department of the Interior

U.S. Geological Survey

Data Series 301

Tehachapi

Kernville

Bakersfield
Photographs by Justin Kulongoski, U.S. Geological Survey.
Ground-Water Quality Data in the Southern 

Sierra Study Unit, 2006—Results from the 

California GAMA Program

By Miranda S. Fram and Kenneth Belitz

Prepared in cooperation with the California State Water Resources Control Board

Data Series 301

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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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 reference:

Fram, M.S., and Belitz, Kenneth, 2007, Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results 

from the California GAMA Program: U.S. Geological Survey Data Series 301, 78 p.
iii

Contents

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

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................2

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

Hydrogeologic Setting...................................................................................................................................4

Methods...........................................................................................................................................................4

Study Design..........................................................................................................................................4

Sample Collection and Analysis.........................................................................................................6

Data Reporting.......................................................................................................................................9

Quality Assurance.................................................................................................................................9

Ground-Water Quality Results.....................................................................................................................9

Quality-Control Sample Results..........................................................................................................9

Comparison Thresholds.......................................................................................................................9

Water-Quality Data.............................................................................................................................11

Field Parameters........................................................................................................................11

Organic Constituents.................................................................................................................11

Constituents of Special Interest..............................................................................................11

Inorganic Constituents..............................................................................................................11

Inorganic Tracer Constituents .................................................................................................12

Radioactive Constituents..........................................................................................................12

Microbial Indicators..................................................................................................................13

Future Work .........................................................................................................................................13

Summary........................................................................................................................................................13

References Cited..........................................................................................................................................14

Appendix........................................................................................................................................................53

Sample Collection and Analysis.......................................................................................................53

Data Reporting.....................................................................................................................................55

Laboratory Reporting Conventions .........................................................................................55

Constituents on Multiple Analytical Schedules....................................................................56

Quality Assurance...............................................................................................................................56

Blanks .........................................................................................................................................56

Replicates....................................................................................................................................57

Matrix Spikes..............................................................................................................................57

Surrogates...................................................................................................................................58

Quality-Control Sample Results........................................................................................................58

Detections in Field and Source-Solution Blanks..................................................................58

Variability in Replicate Samples..............................................................................................59

Matrix-Spike Recoveries..........................................................................................................59

Surrogate Compound Recoveries...........................................................................................60

Internal Laboratory Quality-Control Samples for Pharmaceutical Compounds..............60
iv

Figures

Figure 1. Map of the hydrogeologic provinces of California and the location of the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study unit .................................................................................... 3

Figure 2. Map of the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study unit showing the California Department of Water Resources 

ground-water basins within the study unit and major hydrologic 

features ....................................................................................... 5

Figure 3. Map of the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study unit showing the 1.86-mile buffer zones around all public-supply 

wells, the distribution of study area grid cells, and the location of sampled 

grid wells .................................................................................... 7

Figure 4. Map of the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study unit showing the 1.86-mile buffer zones around all 

public-supply wells, the distribution of study area grid cells, and the location of 

sampled flow-path wells .................................................................. 8

Tables

Table 1. Identification, sampling, and construction information for wells sampled for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 19

Table 2. Classes of chemical and microbial constituents and water-quality indicators 

collected for the slow, intermediate, and fast well sampling schedules in the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 21

Table 3A. Volatile organic compounds and gasoline additives, primary uses or sources, 

comparative thresholds, and reporting information for the USGS National Water 

Quality Laboratory schedule 2020 ......................................................... 22

Table 3B. Gasoline oxygenates and degradates, primary uses or sources, comparative 

thresholds, and reporting information for the USGS National Water Quality 

Laboratory schedule 4024 .................................................................. 25

Table 3C. Pesticides and pesticide degradates, primary uses or sources, comparative 

thresholds, and reporting information for the USGS National Water Quality 

Laboratory schedule 2003 .................................................................. 26

Table 3D. Pharmaceutical compounds, primary uses or sources, comparative thresholds, 

and reporting information for the USGS National Water Quality Laboratory 

schedule 2080 .............................................................................. 28

Table 3E. Wastewater-indicator compounds, primary uses or sources, comparative 

thresholds, and reporting information for the USGS National Water Quality 

Laboratory schedule 1433 .................................................................. 29

Table 3F. Constituents of special interest, primary uses or sources, comparative 

thresholds, and reporting information for the Montgomery Watson-Harza 

Laboratory .................................................................................... 31

Table 3G. Nutrients and dissolved organic carbon, comparative thresholds, and reporting 

information for the USGS National Water Quality Laboratory schedule 2755 and 

parameter code 2613........................................................................ 32
Table 3H. Major and minor ions and trace elements, comparative thresholds, and 

reporting information for the USGS National Water Quality Laboratory schedule 

1948 .......................................................................................... 33

Table 3I. Arsenic, chromium, and iron species, comparative thresholds, and reporting 

information for the USGS Trace Metal Laboratory, Boulder, Colorado ............... 34

Table 3J. Isotopic and radioactive constituents, comparative thresholds, and reporting 

information for laboratories ............................................................... 35

Table 3K. Noble gases and tritium, comparison thresholds, and reporting information 

for the Lawrence Livermore National Laboratory ....................................... 36

Table 3L. Microbial constituents, comparison thresholds, and reporting information for 

the USGS Ohio Microbiology Laboratory parameter codes 90901, 90900, 99335, 

and 99332 .................................................................................... 37

Table 4. Water-quality indicators in samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006 .................................................................................... 38

Table 5. Volatile organic compounds (VOCs), and gasoline oxygenates and degradates 

detected in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006 .................. 40

Table 6. Pesticides and pesticide degradates detected in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 41

Table 7. Pharmaceutical compounds detected in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006 ........................................................................ 42

Table 8. Constituents of special interest [Perchlorate, N-Nitrosodimethylamine (NDMA), 

and 1,2,3-Trichloropropane (1,2,3-TCP)] detected in samples collected in the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 43

Table 9. Nutrients and dissolved organic carbon detected in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 44

Table 10. Major and minor ions and dissolved solids detected in samples collected for 

the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 45

Table 11. Trace elements detected in ground-water samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, July to September 2006. ...................................................... 46

Table 12. Species of inorganic arsenic, iron, and chromium in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 48

Table 13. Results for analyses of stable isotope ratios and tritium and carbon-14 activities 

in samples collected for the Southern Sierra Groundwater Ambient Monitoring 

and Assessment (GAMA) study, California, June 2006 ................................. 49

Table 14. Radioactive constituents detected in samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006 .................................................................................... 51
Table 15. Microbial indicators detected in samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006 .................................................................................... 52

Table A1. Analytical methods used for the determination of organic, inorganic, and 

microbial constituents by the U.S. Geological Survey (USGS) National Water 

Quality Laboratory (NWQL) and additional contract laboratories ..................... 61

Table A2. Preferred analytical schedules for constituents appearing on multiple 

schedules for samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006 .................. 63

 Table A3. Constituents detected in field blanks collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006 .................................................................................... 64

Table A4A. Quality-control summary for replicate analyses of organic constituents 

detected in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006 .................. 65

Table A4B. Quality-control summary for replicate analyses of major and minor ions and 

nutrients detected in samples collected for the Southern Sierra Groundwater 

Ambient Monitoring and Assessment (GAMA) study, California, June 2006 ......... 66

Table A4C. Quality-control summary for replicate analyses of trace elements detected in 

samples collected for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, June 2006....................................... 67

Table A4D. Quality-control summary of replicate analyses of constituents of special 

interest and radioactive constituents detected in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 68

Table A5A. Quality-control summary for matrix-spike recoveries of volatile organic 

compounds (VOCs) and gasoline oxygenates and degradates in samples 

collected for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, June 2006....................................... 69

Table A5B. Quality-control summary for matrix-spike recoveries of pesticides and 

pesticide degradates in samples collected for the Southern Sierra Groundwater 

Ambient Monitoring and Assessment (GAMA) study, California, June 2006 ......... 71

Table A5C. Quality-control summary for matrix-spike recoveries of pharmaceutical 

compounds in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006 .................. 73

Table A5D. Quality-control summary for matrix-spike recoveries of wastewater-indicator 

compounds in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006 .................. 74

Table A5E. Quality-control summary for matrix-spike recoveries of N-Nitrosodimethylamine 

(NDMA) and 1,2,3-Trichloropropane (1,2,3-TCP) in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006 ............................................................... 75

Table A6. Quality-control summary for surrogate recoveries of volatile organic 

compounds, gasoline oxygenates and degradates, pesticides and pesticide 

degradates, pharmaceutical compounds, wastewater-indicator compounds, 

and constituents of special interest in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006 ........................................................................ 76

vi
Table A7A. Quality-control summary for laboratory “set blanks” for pharmaceutical 

compounds corresponding to analyses of samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006 ........................................................................ 77

Table A7B. Quality-control summary for laboratory “set spikes” for pharmaceutical 

compounds corresponding to analyses of samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006 ........................................................................ 78

Abbreviations and Acronyms

AB Assembly Bill (through the California State Assembly)

AL action level

CAS Chemical Abstract Service (American Chemical Society)

CSU combined standard uncertainty

E estimated or having a higher degree of uncertainty

GAMA Groundwater Ambient Monitoring and Assessment program

GPS Global Positioning System

HAL-US lifetime health advisory (USEPA)

HPLC high-performance liquid chromatography

LRL laboratory reporting level

LSD land-surface datum

LT-MDL long-term method detection level

MCL-US maximum contaminant level (USEPA)

MCL-CA maximum contaminant level (CDHS)

MD method detection level

MDL method detection limit

MRL minimum reporting level

MU method uncertainty

N Normal (1-gram-equivalent per liter of solution)

na not available

nc sample not collected

NL-CA notification level (CDHS)

NWIS National Water Information System (USGS)

PCFF-GAMA personal computer field forms program designed for GAMA sampling

QC quality control

RPD relative percent difference

RSD relative standard deviation

RSD5 risk-specific dose at 10-5 (USEPA)

SMCL secondary maximum contaminant level (USEPA)

SMCL-CA secondary maximum contaminant level (CDHS)

SMCL-US secondary maximum contaminant level (USEPA)

SOSA Southern Sierra study unit

SOSAFP Southern Sierra study unit flow path

SSMDC sample-specific minimum detectable concentration

TT-US treatment technique (USEPA)

US United States

vii
Organizations

CDHS California Department of Health Services

USEPA U.S. Environmental Protection Agency

LLNL Lawrence Livermore National Laboratory

MWH Montgomery Watson-Harza

NAWQA National Water Quality Assessment (USGS)

NWQL National Water Quality Laboratory (USGS)

SWRCB State Water Resources Control Board

TCCWD Tehachapi-Cummings County Water District

USGS U.S. Geological Survey

Selected chemical names

CaCO3 calcium carbonate

CFC chlorofluorocarbon

CO3

-2 carbonate

DOC dissolved organic carbon

HCl hydrochloric acid

HCO3

- bicarbonate

MTBE methyl tert-butyl ether

NDMA N-nitrosodimethylamine

PCE tetrachloroethene

TCP trichloropropane

TDS total dissolved solids

THM trihalomethane

VOC volatile organic compound

Units of Measure

cm3

 STP/g cubic centimeters of gas at standard temperature and pressure (0 degrees Celsius and 1 

atmosphere of pressure) per gram of water

ft foot (feet)

in inch

L liter

mg milligram

mg/L milligrams per liter (parts per million)

mi mile

mL milliliter

μg/L micrograms per liter (parts per billion)

μL microliter

μm micrometer

pCi/L picocurie per liter

Notes

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

 °F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

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). Milligrams per liter is equivalent to parts per million (ppm) and 

micrograms per liter is equivalent to parts per billion (ppb).

viii
Abstract

Ground-water quality in the approximately 1,800 squaremile Southern Sierra study unit (SOSA) was investigated in 

June 2006 as part of the Statewide Basin Assessment Project 

of the Groundwater Ambient Monitoring and Assessment 

(GAMA) Program. The GAMA Statewide Basin Assessment 

Project was developed in response to the Groundwater Quality 

Monitoring Act of 2001 and is being conducted by the U.S. 

Geological Survey (USGS) in cooperation with the California 

State Water Resources Control Board (SWRCB). 

The Southern Sierra study was designed to provide a spatially unbiased assessment of raw ground-water quality within 

SOSA, as well as a statistically consistent basis for comparing 

water quality throughout California. Samples were collected 

from fifty wells in Kern and Tulare Counties. Thirty-five of the 

wells were selected using a randomized grid-based method to 

provide statistical representation of the study area, and fifteen 

were selected to evaluate changes in water chemistry along 

ground-water flow paths.

The ground-water samples were analyzed for a large 

number of synthetic organic constituents [volatile organic 

compounds (VOCs), pesticides and pesticide degradates, pharmaceutical compounds, and wastewater-indicator compounds], 

constituents of special interest [perchlorate, N-nitrosodimethylamine (NDMA), and 1,2,3-trichloropropane (1,2,3-TCP)], 

naturally occurring inorganic constituents [nutrients, major 

and minor ions, and trace elements], radioactive constituents, 

and microbial indicators. Naturally occurring isotopes [tritium, 

and carbon-14, and stable isotopes of hydrogen and oxygen in 

water], and dissolved noble gases also were measured to help 

identify the source and age of the sampled ground water.

Quality-control samples (blanks, replicates, and samples 

for matrix spikes) were collected for approximately one-eighth 

of the wells, and the results for these samples were used to 

evaluate the quality of the data for the ground-water samples. 

Assessment of the quality-control information resulted in 

censoring of less than 0.2 percent of the data collected for 

ground-water samples.

This study did not attempt to evaluate the quality of water 

delivered to consumers; after withdrawal from the ground, 

water typically is treated, disinfected, or blended with other 

waters to maintain acceptable water quality. Regulatory thresholds apply to treated water that is served to the consumer, not 

to raw ground water. However, to provide some context for 

the results, concentrations of constituents measured in the raw 

ground water were compared with health-based thresholds 

established by the U.S. Environmental Protection Agency 

(USEPA) and California Department of Public Health (CDPH) 

and thresholds established for aesthetic concerns (secondary 

maximum contaminant levels, SMCL-CA) by CDPH.

VOCs and pesticides were detected in less than one-third 

of the grid wells, and all detections in samples from SOSA 

wells were below health-based thresholds. All detections of 

trace elements and nutrients in samples from SOSA wells 

were below health-based thresholds, with the exception of four 

detections of arsenic that were above the USEPA maximum 

contaminant level (MCL-US) and one detection of boron that 

was above the CDPH notification level (NL-CA). All detections of radioactive constituents were below health-based 

thresholds, although four samples had activities of radon-222 

above the proposed MCL-US. Most of the samples from 

SOSA wells had concentrations of major elements, total dissolved solids, and trace elements below the non-enforceable 

thresholds set for aesthetic concerns. A few samples contained 

iron, manganese, or total dissolved solids at concentrations 

above the SMCL-CA thresholds.

Introduction

Ground water comprises nearly half of the water used for 

public supply in California (Hutson and others, 2004). 

To assess the quality of ground water in aquifers used for 

drinking-water supply and to establish a program for monitoring trends in ground-water quality, the State Water Resources 

Control Board (SWRCB), in collaboration with the U.S. 

Geological Survey (USGS) and Lawrence Livermore National 

Laboratory (LLNL), implemented the Groundwater Ambient 

Monitoring and Assessment (GAMA) Program (http://www.

waterboards.ca.gov/gama). The GAMA program consists of 

three projects: Statewide Basin Assessment, conducted by the 

USGS (http://ca.water.usgs.gov/gama/); Voluntary Domestic 

Well Assessment, conducted by the SWRCB; and Special 

Studies, conducted by LLNL.

Ground-Water Quality Data in the Southern Sierra Study 

Unit, 2006—Results from the California GAMA Program

By Miranda S. Fram and Kenneth Belitz
The SWRCB initiated the GAMA Statewide Basin 

Assessment project in response to the Groundwater Quality 

Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code, Assembly Bill 599). AB 599 is a public 

mandate to assess and monitor the quality of ground water 

used as public supply for municipalities in California. The 

project is a comprehensive assessment of statewide groundwater quality designed to help better understand and identify 

risks to ground-water resources, and to increase the availability of information about ground-water quality to the public. As 

part of the AB 599 process, the USGS, in collaboration with 

the SWRCB, developed the monitoring plan for the project 

(Belitz and others, 2003; State Water Resources Control 

Board, 2003). Key aspects of the project are inter-agency collaboration and cooperation with local water agencies and well 

owners. Local participation in the project is entirely voluntary.

The GAMA Statewide Basin Assessment project is 

unique because the data collected during the study include 

analyses for an extensive number of chemical constituents 

at very low concentrations, analyses that are not normally 

available. A broader understanding of ground-water composition will be especially useful for providing an early indication 

of changes in water quality, and for identifying the natural 

and human factors affecting water quality. Additionally, the 

GAMA Statewide Basin Assessment project will analyze a 

broader suite of constituents than required by the California 

Department of Public Health (CDPH). An understanding of 

the occurrence and distribution of these constituents is important for the long-term management and protection of groundwater resources.

 The range of hydrologic, geologic, and climatic conditions that exist in California must be considered in an assessment of ground-water quality. Belitz and others (2003) partitioned the state into ten hydrogeologic provinces, each with 

distinctive hydrologic, geologic, and climatic characteristics 

(fig. 1), and representative regions in all ten provinces were 

included in the project design. Eighty percent of California’s 

approximately 16,000 public-supply wells are located in 

ground-water basins within these hydrologic provinces. These 

ground-water basins, defined by the California Department of 

Water Resources, generally consist of relatively permeable, 

unconsolidated deposits of alluvial or volcanic origin (California Department of Water Resources, 2003). Ground-water 

basins were prioritized for sampling based upon the number of 

public-supply wells in the basin, with secondary consideration 

given to municipal ground-water use, agricultural pumping, 

the number of leaking underground fuel tanks, and pesticide 

applications within the basins (Belitz and others, 2003). In 

addition, some ground-water basins or groups of adjacent 

similar basins with relatively few public-supply wells were 

assigned high priority so that all hydrogeologic provinces 

would be represented in the subset of basins sampled. The 

116 priority basins were grouped into 35 study units. Some 

areas not in the defined ground-water basins were included in 

several of the study units to achieve representation of the 20 

percent of public-supply wells not located in the ground-water 

basins.

Three types of water-quality assessments are being conducted with the data collected in each study unit: (1) Status: 

assessment of the current quality of the ground-water resource, 

(2) Trends: detection of changes in ground-water quality, and 

(3) Understanding: identification of the natural and human 

factors affecting ground-water quality (Kulongoski and Belitz, 

2004). This report is one of a series of reports presenting 

assessments of current water-quality conditions in each study 

unit (Wright and others, 2005; Kulongoski and others, 2006; 

Bennett and others, 2006; Dawson and others, 2007; Kulongoski and Belitz, 2007). Subsequent interpretive reports will 

address the trends and understanding aspects of the waterquality assessments.

The Southern Sierra GAMA study unit, hereafter referred 

to as SOSA, contains six small ground-water basins and also 

encompasses areas outside of the defined ground-water basins. 

SOSA was considered high priority for sampling to provide 

adequate representation of the Sierra Nevada hydrogeologic 

province (Belitz and others, 2003).

Purpose and Scope

The purposes of this report are: (1) to describe the 

hydrogeologic setting of SOSA, (2) to detail the sampling 

and analytical methods, and quality assurance used during the 

study, (3) to present the results of quality-control tests, and 

(4) to present the analytical results for ground-water samples 

collected in SOSA. Ground-water samples were analyzed for 

organic, inorganic, and microbial constituents, field parameters, and chemical tracers. The chemical and microbial data 

presented in this report were evaluated by comparison to state 

and federal drinking water regulatory and other health-based 

standards that are applied to treated drinking water. Regulatory 

thresholds considered for this report are those established by 

the United States Environmental Protection Agency (USEPA) 

and the California Department of Public Health (CDPH). The 

data presented in this report are intended to characterize the 

quality of untreated ground-water resources within the study 

unit, not the treated drinking water delivered to consumers 

by water purveyors. Discussions of the factors that influence 

the distribution and occurrence of the constituents detected 

in ground-water samples will be the subject of subsequent 

publications.

   Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
!(

!(

!(

!(

!(

San

Diego

Transverse

and Selected

Peninsular Range

Desert

Southern

Coast

Ranges

Basin

and Range

Sierra

Nevada

Central

Valley

Modoc

Plateau and

Cascades

Klamath

Mountains

Northern

Coast

Ranges

San Diego

Sacramento

Redding

Los Angeles

ieBakersf ld

42

124 122 120 118 116 114

40

38

36

34

32

0 50 100 200 MILES

0

Shaded relief derived from U.S. Geological Survey 

National Elevation Dataset, 2006,

Albers Equal Area Conic Projection

Provinces from Belitz and others, 2003

50 100 200 KILOMETERS

Southern Sierra

Study Unit

(SOSA)

ARIZONA

NEVADA

Pacific

Ocean

MEXICO

OREGON

Figure 1. The hydrogeologic provinces of California and the location of the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study unit (black area). Modified from Belitz and others (2003).

Introduction   
Acknowledgments

The authors thank the following cooperators for their 

support: the State Water Resources Control Board (SWRCB), 

California Department of Public Health, California Department of Water Resources, and Lawrence Livermore National 

Laboratory. We especially thank the well owners and water 

purveyors for their generosity in allowing the USGS to collect samples from their wells. Two reviewers, Jan Stepek 

(SWRCB) and Justin Kulongoski (USGS), provided comments 

to improve this work. Funding for this work was provided by 

State bonds authorized by Proposition 50 and administered by 

the SWRCB.

Hydrogeologic Setting

The Southern Sierra study unit (SOSA) covers approximately 1,800 square miles in Kern and Tulare Counties, California, at the southern end of the Sierra Nevada hydrogeologic 

province (fig. 1). The study unit area is defined by the watersheds of Tejon Creek, Tehachapi Creek, the middle and upper 

Kern River, and the East Tehachapi closed drainage basin. 

SOSA includes 6 small ground-water basins, as defined by the 

California Department of Water Resources (fig. 2) (California 

Department of Water Resources, 2003). The wells sampled in 

the southern part of SOSA are in or nearby the Cummings Valley, Brite Valley, Tehachapi Valley West, and Tehachapi Valley 

East ground-water basins. The wells sampled in the northern 

part of SOSA are in or near the Kern River Valley groundwater basin.

SOSA has approximately 8,000 ft of topographic relief. 

The Cummings and Tehachapi basins are relatively flat with 

an altitude of approximately 4,000 ft. The Tehachapi Mountains rise to 7,700 ft south of the Cummings basin, and to over 

8,000 ft south of the Tehachapi basin. Water level in Lake 

Isabella is 2,600 ft, and the peaks of the Sierra Nevada rise up 

to 10,000 ft as near as 40 mi north of the lake. The climate in 

SOSA is characterized by hot, dry summers and cold, wet winters, although the temperatures and precipitation are strongly 

controlled by elevation. Precipitation at Lake Isabella Dam 

(2,635 ft) and in the city of Tehachapi (4,017 ft) averages 11 

inches per year, with 80 to 90 percent falling between November and April (California Department of Water Resources, 

2007). Winter precipitation falls mostly as snow at elevations 

above 5,000 ft.

The Cummings, Brite, Tehachapi West, and Tehachapi 

East basins are all bounded by the Tehachapi Mountains to the 

south and the Sierra Nevada to the north, and are separated 

by north to northwest trending low bedrock ridges or alluvial 

divides (California Department of Water Resources, 2006a, 

b, c, d). The primary water-bearing units are Pleistocene to 

Recent alluvial fans around the margins of the basins deposited by creeks draining the Tehachapi Mountains and Sierra 

Nevada, and floodplain deposits in the centers of the basins 

(Dibblee and Warne, 1970; Dibblee and Louke, 1970; Michael 

and McCann, 1962). The sediments are arkosic cobbles, 

gravels, sands, silts, and clays, with the coarser materials in 

the alluvial fans and the finer sediments in the floodplains. In 

the Tehachapi East basin, water is also found in Miocene to 

Pliocene sedimentary and volcanic units.

Cummings, Brite, Tehachapi West, and Tehachapi East 

are all adjudicated basins and are managed collectively by 

the Tehachapi-Cummings County Water District (TCCWD). 

Beginning in 1973, TCCWD has imported water from the 

State Water Project via a pipeline just upstream of the A.D. 

Edmiston pumping plant (Tehachapi-Cummings County Water 

District, 2004a,b). The system for distributing this water to the 

TCCWD area has expanded over the years so that Cummings, 

Brite, Tehachapi, and Bear Valleys are all now supplied with 

imported water.

The 124-square-mile Kern River basin has an irregular 

shape that follows the dendritic drainage pattern of the Kern 

River and its tributary creeks. The western arm of the basin 

lies in the trace of the Kern Canyon fault. The primary waterbearing units are the Pleistocene to Recent fluvial deposits in 

the channel of the Kern River and around Lake Isabella (California Department of Water Resources, 2006e).

Examination of driller’s logs for wells in areas of SOSA 

outside of the alluvial basins showed that the wells were 

completed in fractured hard-rock. The Mesozoic granitic rocks 

and Paleozoic to Mesozoic metamorphic rocks of the Sierra 

Nevada range are apparently locally water-bearing. Little is 

known about these aquifers.

Methods

Methods used for the GAMA program were selected 

to achieve the following objectives: (1) Design a sampling 

plan suitable for statistical analysis; (2) collect samples in a 

consistent manner; (3) analyze samples using proven and reliable laboratory methods; (4) assure the quality of the groundwater data; and, (5) maintain data securely and with relevant 

documentation.

Study Design

The wells selected for sampling in this study reflect the 

combination of two well selection strategies. Thirty-five wells 

were selected to provide a statistically unbiased, spatially distributed assessment of the quality of ground-water resources 

used for public drinking-water supply, and fifteen additional 

wells were selected to provide greater sampling density in 

several areas to address specific ground-water quality issues in 

the study unit.

   Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Weldon

UV14

U

UV17 8

14 § ̈¦5

UV58

Kern River

basin

Cummings

basin

Lake

Isabella

Tehachapi

Kernville

Fairview

Millersville

Caliente

Weldon

TULARE COUNTY

KERN COUNTY

36

11830 118

3530

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0 10 20 MILES

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Tehachapi

basins

Kernville

Fairview

Caliente

Millersville

Mojave

Playa

Kern River

Brite

basin

EXPLANATION

Southern Sierra Study Unit (SOSA)

Department of Water Resources ground-water basins

Major Road and Highways

Shaded relief derived from U.S. Geological Survey 

National Elevation Dataset, 2006,

Albers Equal Area Conic Projection

58

Figure 2. The Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study unit showing 

the California Department of Water Resources ground-water basins within the study unit and major hydrologic 

features.

Methods 
The spatially distributed wells were selected using a 

randomized grid-based method (Scott, 1990). SOSA had 

relatively few public-supply wells, and these wells were not 

evenly distributed. To minimize the number of cells without 

any wells, only the portion of SOSA in close proximity to a 

public-supply well was included in the gridded area. Locations 

of wells listed in statewide databases maintained by the CDPH 

and USGS were plotted and 1.86-mi (3-kilometer) radius 

circles were drawn around each well. The area encompassed 

by the circles was then divided into forty 10-mi2 grid cells 

(fig. 3). The objective was to select one public-supply well 

per grid cell. Thirty-five of the forty grid cells were sampled 

in SOSA; the other five grid cells did not contain accessible 

wells. If a grid cell contained more than one public-supply 

well, each well was randomly assigned a rank. The lowest 

ranking well that met basic sampling criteria (for example, 

sampling point located prior to treatment, capability to 

pump for several hours, and available well-construction 

information), and for which permission to sample could 

be obtained, was then sampled. If a grid cell contained no 

accessible public-supply wells, domestic and irrigation wells 

were considered for sampling. An attempt was made to 

select domestic and irrigation wells with depths and screened 

intervals similar to those in public-supply wells in the area. 

In this fashion, a well was selected in each cell to provide a 

spatially distributed, randomized monitoring network for each 

study area. Wells sampled as part of the randomized grid-cell 

network are hereafter referred to as “grid wells.” Grid wells in 

SOSA were numbered in the order of sample collection with 

the prefix “SOSA.”

Additional wells were sampled along the axis of the 

Tehachapi basin (SOSAFP-05, -04, -15, -03, -01, -06, -14, 

-13), in the central portion of the Cummings basin 

(SOSAFP-07, -08, -09, -10, -11, -12), and along the Kern 

River (SOSAFP-02 (fig. 4). These wells were sampled to 

assess movement of water and dissolved constituents along 

ground-water flow paths in these areas in combination with 

selected wells that were sampled on the grid. Wells sampled 

as part of these studies for better understanding were not 

included in the statistical characterization of water quality in 

SOSA. These additional wells were numbered in the order of 

sample collection with the prefix “SOSAFP” (“FP” indicating 

“flow path”).

Table 1 (all tables shown in back of report) provides 

the GAMA alphanumeric identification number for each 

well, along with the date sampled, sampling schedule, well 

elevation, and well-construction information. Ground-water 

samples were collected from 40 public-supply wells, 5 irrigation wells, and 5 domestic wells during June 2006.

Well locations and identifications were verified using 

GPS, 1:24,000 scale USGS topographic maps, comparison 

with existing well information in USGS and CDPH databases, 

and information provided by well owners. Driller’s logs 

for wells were obtained when available. Well information 

was recorded by hand on field sheets and electronically 

using specialized software on field laptop computers. All 

information was verified and then uploaded into the USGS 

National Water Information System (NWIS). In order to 

maintain confidentiality of well owners and well locations, the 

standard USGS protocol for identifying sites in NWIS with a 

site-id containing latitude and longitude was modified for new 

sites established in this study, and all data are currently inaccessible from NWIS’s public website.

The wells in SOSA were sampled using a tiered analytical approach. All wells were sampled for a standard set of 

constituents, including VOCs, pesticides and pesticide degradates, pharmaceutical compounds, perchlorate, hexavalent 

chromium, stable isotopes of water, and dissolved noble gases 

and tritium/helium age dates. The standard set of constituents 

was termed the “fast” schedule (table 2). Wells on the “intermediate” schedule were sampled for all the constituents on the 

fast schedule, plus NDMA, 1,2,3-TCP, nutrients and dissolved 

organic carbon, major and minor ions and trace elements, and 

tritium. Wells on the “slow” schedule were sampled for all the 

constituents on the intermediate schedule, plus radioactive and 

microbial constituents (table 2). Fast, intermediate, and slow 

refer to the time required to sample the well for all the analytes 

on the schedule. Generally, one slow or two intermediate or 

four fast wells could be sampled in one day. In SOSA, twentyeight of the ground-water wells were sampled on the fast 

schedule, fifteen were sampled on the intermediate schedule, 

and seven on the slow schedule.

Sample Collection and Analysis

Samples were collected in accordance with the protocols 

established by the USGS National Water Quality Assessment 

(NAWQA) program (Koterba and others, 1995) and the USGS 

National Field Manual (U.S. Geological Survey, variously 

dated). These sampling protocols ensure that a representative 

sample of ground water is collected at each site and that the 

samples are collected and handled in a way that minimizes the 

potential for contamination of samples. The methods used for 

sample collection are described in the Appendix.

Tables 3A–L list the compounds analyzed in each 

constituent class. Ground-water samples were analyzed for 

eighty-five VOCs (table 3A), eight gasoline oxygenates and 

degradates (table 3B), sixty-three pesticides and pesticide degradates (table 3C), fourteen pharmaceutical compounds (table 

3D), sixty-two wastewater-indicator compounds (table 3E), 

three constituents of special interest (table 3F), five nutrients 

and dissolved organic carbon (table 3G), ten major and minor 

ions and total dissolved solids (table 3H), twenty-five trace 

elements (table 3H), arsenic, iron, and chromium species 

(table 3I), stable isotopes of water, eight radioactive constituents, including tritium and carbon-14 (table 3J), five dissolved 

noble gases, and helium stable isotope ratios (table 3K), and 

four microbial constituents (table 3L). The methods used for 

sample analysis are described in the Appendix.

   Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
05

06

35

28

34

32

09 13

01

11

33

26

27

25 24

23

08

04

02

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22

12

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10

31

30

18

03

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Playa

Shaded relief derived from U.S. Geological Survey 

National Elevation Dataset, 2006,

Albers Equal Area Conic Projection

04

EXPLANATION

Southern Sierra Study Unit (SOSA)

Department of Water Resources ground-water basins

Grid well

Figure 3. The Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study unit showing the 

1.86-mile buffer zones around all public-supply wells, the distribution of study area grid cells, and the location of 

sampled grid wells.

Alphanumeric identification numbers for grid wells have the prefix “SOSA”; only the numeric portions are shown 

on the map.

Methods 
Figure 4. The Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study unit showing 

the 1.86-mile buffer zones around all public-supply wells, the distribution of study area grid cells, and the 

location of sampled flow-path wells.

Alphanumeric identification numbers for flow-path wells have the prefix “SOSFP”; only the numeric portions are 

shown on the map.

02

14

13

01

06

15

03

04

05

10

12

07

08

09

11

12

EXPLANATION

Southern Sierra Study Unit (SOSA)

Department of Water Resources ground-water basins

Flow-path well Playa

Shaded relief derived from U.S. Geological Survey 

National Elevation Dataset, 2006,

Albers Equal Area Conic Projection

36

11830 118

3530

35

0 10 20 MILES

0 10 20 KILOMETERS

 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Data Reporting

The methods and conventions used for reporting the data 

are described in the Appendix. Nineteen constituents analyzed 

in this study were measured by more than one method at the 

USGS National Water Quality Laboratory (NWQL), but only 

the results from the preferred method are reported. Arsenic, 

iron, and chromium concentrations, and tritium activities were 

measured by more than one laboratory, and both sets of results 

are reported.

Quality Assurance

The quality-assurance plan used for this study follows 

the protocols described in the NWQL quality-assurance plan 

(Maloney, 2005; Pirkey and Glodt, 1998) and the protocols 

used by the USGS NAWQA program (Koterba and others, 

1995). Quality-control (QC) samples collected in the SOSA 

study include source-solution blanks, field blanks, replicates, 

and matrix and surrogate spikes. QC samples were collected 

to evaluate contamination, and bias and variability of the water 

chemistry data that may have resulted from sample collection, 

processing, storage, transportation, and laboratory analysis. 

The quality-assurance plan is described in the Appendix.

Ground-Water Quality Results

Results from analyses of raw (untreated) ground-water 

samples from SOSA are presented in tables 4 through 15. 

Ground-water samples collected in SOSA were analyzed for 

up to 300 constituents, and 210 of those constituents were 

not detected in any of the samples (tables 3A–L). The results 

tables present only the constituents that were detected, and 

list only samples that had at least one constituent detected. 

For constituent classes that were analyzed at all of the grid 

wells, the tables include the number of wells at which each 

analyte was detected, the frequency at which it was detected 

(in relation to the number of grid wells), and the total number 

of constituents detected at each well. Results from the flowpath wells are presented in the tables, but these results were 

excluded from the detection frequency calculations to avoid 

statistically over-representing the areas in the vicinity of the 

flow-paths.

Table 4 includes water-quality indicators measured in 

the field and at the NWQL, while tables 5 through 15 present 

the results of ground-water analyses organized by compound 

classes:

Organic constituents

VOCs and gasoline oxygenates and degradates 

(table 5)

Pesticides and pesticide degradates (table 6)

Pharmaceutical compounds (table 7)

•

•

•

•

Constituents of special interest (table 8)

Inorganic constituents

Nutrients and dissolved organic carbon (table 9)

Major and minor ions and dissolved solids (table 10)

Trace elements (table 11)

Arsenic, iron, and chromium speciation (table 12)

Inorganic tracer constituents (table 13)

Radioactive constituents (table 14)

Microbial indicators (table 15)

The wastewater-indicator compounds have no summary 

table because the only compound detected, tetrachloroethene 

(PCE), also was analyzed on the volatile organic compound 

analytical schedule (table 3A) that is the preferred method for 

this compound (see Appendix). PCE results appear on table 5.

Quality-Control Sample Results

Results of quality-control analyses (blanks, replicates, 

matrix spikes, and surrogates) were used to evaluate the 

quality of the data for the ground-water samples. Assessment 

of the blanks resulted in censoring of less than 0.2 percent of 

the data for the ground-water samples. Matrix-spike recoveries 

for a number of organic constituents were lower than the 

lower end of the acceptable limits, which may indicate that 

these constituents might not have been detected in some 

samples if they were present at very low concentrations. The 

quality-control results are described in the Appendix.

Comparison Thresholds

Detected concentrations in ground-water samples were 

compared with CDPH and USEPA drinking-water healthbased thresholds (California Department of Public Health, 

2007a; U.S. Environmental Protection Agency, 2006). The 

chemical and microbial data presented in this report are 

meant to characterize the quality of the untreated groundwater resources within SOSA, and are not intended to represent 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 

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

atmosphere prior to its delivery to consumers.

•

•

•

•

•

•

•

•

•

Ground-water Quality Results 
The following thresholds were used for comparisons:

MCL– Maximum Contaminant Level. Legally 

enforceable standards that apply to public water 

systems and are designed to protect public health by 

limiting the levels of contaminants in drinking water. 

MCLs established by the USEPA are the minimum 

standards with which states are required to comply, 

and individual states may choose to set more stringent 

standards. CDPH has established MCLs for additional 

constituents not regulated by the USEPA, as well as 

lowered the threshold concentration for a number of 

constituents with MCLs established by the USEPA. In 

this report, a threshold set by the USEPA and adopted 

by CDPH is labeled “MCL-US”, and one set by CDPH 

that is more stringent than the MCL-US is labeled 

“MCL-CA”. CDPH is notified when constituents 

are detected at concentrations exceeding MCL-US 

or MCL-CA thresholds in samples collected for the 

GAMA Statewide Basin Assessment project.

AL – Action Level. Legally enforceable standards that 

apply to public water systems and are designed to protect public health by limiting the levels of copper and 

lead in drinking water. Detections of copper or lead 

above thresholds trigger requirements for mandatory 

water treatment to reduce the corrosiveness of water 

to water pipes. The action levels established by the 

USEPA and CDPH are the same, thus the thresholds 

are labeled “AL-US” in this report.

TT – Treatment Technique. Legally enforceable 

standards that apply to public-water systems and are 

designed to protect public health by limiting the levels 

of microbial constituents in drinking water. Detections of microbial constituents above thresholds trigger 

requirements for mandatory additional disinfection 

during water treatment. The action levels established 

by the USEPA and CDPH are the same, thus the 

thresholds are labeled “TT-US” in this report.

SMCL – Secondary Maximum Contaminant Level. 

Non-enforceable standards applied to constituents that 

affect the aesthetic qualities of drinking water, such as 

taste, odor, and color, or technical qualities of drinking 

water, such as scaling and staining. Both the USEPA 

and CDPH define SMCLs, but unlike MCLs, SMCLs 

established by CDPH are not required to be at least 

as stringent as those established by USEPA. SMCLs 

established by CDPH are used in this report (SMCLCA) for all constituents that have SMCL-CA values. 

The SMCL-US is used for pH because no SMCL-CA 

has been defined.

•

•

•

•

NL – Notification Level. Health-based notification 

levels established by CDPH for some of the constituents in drinking water that lack MCLs (NL-CA). If 

a constituent is detected above its NL-CA, State law 

requires timely notification of local governing bodies 

and recommends consumer notification.

HAL – Lifetime Health Advisory Level. The maximum concentration of a constituent at which its presence in drinking water is not expected to cause any 

adverse carcinogenic effects for a lifetime of exposure. 

HALs are established by the USEPA (HAL-US) and 

are calculated assuming consumption of 2 liters (2.1 

quarts) of water per day over a 70-year lifetime by a 

70-kilogram (154-pound) adult and that 20 percent of a 

person’s exposure comes from drinking water.

RSD5 – Risk-Specific Dose. The concentration of 

a constituent in drinking water corresponding to an 

excess estimated lifetime cancer risk of 1 in 100,000. 

RSD5 is an acronym for risk-specific dose at 10-5. 

RSD5s are calculated by dividing the 10-4 Cancer 

risk concentrations established by the USEPA by 10 

(RSD5-US).

For constituents with MCLs, detections in ground-water 

samples were compared to the MCL-US or MCL-CA. Constituents with SMCLs were compared with the SMCL-CA. 

For chloride, sulfate, specific conductance, and total dissolved 

solids, CDPH defines a “recommended” and an “upper” 

SMCL-CA; detections of these constituents in ground-water 

samples were compared with both levels. The SMCL-US for 

these constituents corresponds to the recommended SMCLCA. Detected concentrations of constituents that lack an MCL 

or SMCL were compared to the NL-CA. For constituents that 

lack an MCL, SMCL, or NL-CA, detected concentrations were 

compared with the HAL-US. For constituents that lack an 

MCL, SMCL, NL-CA, or HAL-CA, detected concentrations 

were compared with the RSD5-US. Note that this hierarchy of 

selection of comparison thresholds means that for constituents 

that have multiple types of established thresholds, the threshold used for comparison purposes may not be the one with 

the lowest concentration. The comparison thresholds used in 

this report are listed in tables 3A–L for all constituents and in 

tables 4–15 for constituents detected in ground-water samples 

from SOSA. Not all constituents analyzed for this study have 

established thresholds available. Detections of constituents at 

concentrations greater than the selected comparison threshold 

are marked with asterisks in tables 4–15.

•

•

•

10 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Water-Quality Data

Field Parameters

Field and laboratory measurements of dissolved oxygen, 

pH, specific conductance, alkalinity, and associated parameters 

(turbidity and water temperature) are presented in table 4. Dissolved oxygen and alkalinity are used as indicators of natural 

processes that control water chemistry. Specific conductance 

is the unit electrical conductivity of the water, and is proportional to amount of total dissolved solids (TDS) in the water. 

The pH value indicates the acidity or basicity of the water. 

Two wells had specific conductance values above the recommended SMCL-CA, although only one well was also above 

the upper threshold and this well was not a public-supply well. 

Three wells had pH values outside of the SMCL-US range for 

pH. Laboratory pH values may be higher than field pH values 

because the pH of ground water often increases upon exposure 

to the atmosphere (see Appendix).

Organic Constituents

Volatile organic compounds (VOCs) are present in paints, 

solvents, fuels, fuel additives, refrigerants, fumigants, and 

disinfected water, and are characterized by their tendency to 

evaporate. VOCs generally persist longer in ground water than 

in surface water because ground water is isolated from the 

atmosphere. All detections of VOCs in samples from SOSA 

were below health-based thresholds, and most were less than 

one one-hundredth of the threshold values (table 5). Approximately 30 percent of the grid wells sampled had at least one 

detection of a VOC. The only VOCs detected in more than 

10 percent of the grid wells were chloroform, a byproduct of 

drinking-water disinfection, and tetrachloroethene (PCE), a 

solvent used for dry-cleaning.

Pesticides include herbicides, insecticides, and fungicides, and are used to control weeds, insects, fungi, and other 

pests in agricultural, urban, and suburban settings. All detections of pesticides in samples from SOSA were below healthbased thresholds, and all were less than one one-hundredth of 

the threshold values (table 6). Approximately 25 percent of the 

grid wells sampled had at least one detection of a pesticide. 

The only pesticides detected in more than 10 percent of the 

wells were the herbicides atrazine and simazine, and deethylatrazine, a degradate of atrazine. These three compounds are 

among the most commonly detected pesticide compounds in 

ground water nationally (Gilliom and others, 2006).

Two pharmaceutical compounds were detected in 

samples from three wells in SOSA at very low concentrations 

(table 7). The concentrations were less than one hundred-millionth of the concentration of a typical daily dose dissolved in 

one cup of water.

Constituents of Special Interest

Perchlorate, NDMA, and 1,2,3-TCP are constituents 

of special interest in California because they recently have 

been found to be widely distributed in water supplies (California Department of Public Health, 2007b). Perchlorate was 

detected in approximately 10 percent of the grid wells, and 

all concentrations measured in SOSA wells were less than 

one-third of the NL-CA (table 8). Only one sample contained 

1,2,3-TCP, but the concentration was greater than the NL-CA. 

NDMA was not detected in any samples.

Inorganic Constituents

Unlike the organic constituents and the constituents of 

special interest, most of the inorganic constituents are naturally present in ground water, although their concentrations 

may be influenced by human activities.

The nutrients, nitrogen and phosphorus, and the dissolved 

organic carbon present in ground water can affect biological 

activity in aquifers and in surface- water bodies that receive 

ground-water discharge. Nitrogen may be present in the form 

of ammonia, nitrite, or nitrate depending on the oxidationreduction state of the ground water. High concentrations of 

nitrate can adversely affect human health, particularly the 

health of infants. All concentrations of nitrate, nitrite, and 

ammonia measured in samples from SOSA wells were below 

health-based thresholds (table 9). Concentrations of phosphorus and dissolved organic carbon were also low.

 The major-ion composition, total dissolved solids (TDS) 

content, and levels of certain trace elements in ground water 

affect the aesthetic properties of water, such as taste, color, and 

odor, and the technical properties, such as scaling and staining. 

Although there are no adverse health effects associated with 

these properties, they may reduce consumer satisfaction with 

the water or may have economic impacts. CDPH has established non-enforceable thresholds (SMCL-CAs) that are based 

on aesthetic or technical properties rather than health-based 

concerns for the major ions chloride and sulfate, TDS, and 

several trace elements.

 The concentrations of chloride and sulfate measured in 

samples from SOSA wells were all below the recommended 

SMCL-CAs (table 10). Two samples contained TDS above the 

recommended SMCL-CA, but only one was also above the 

upper SMCL-CA and this well was not a public-supply well.

Eighteen of the twenty-five trace elements analyzed in 

this study have health-based thresholds. Detections of all trace 

elements in samples from SOSA wells were below healthbased thresholds, with the exception of arsenic and boron 

(table 11). Samples from four wells had arsenic concentrations 

above the MCL-US. One of these samples also had a boron 

concentration above the NL-CA, although the sample was not 

from a public-supply well.

Ground-water Quality Results 11
Iron and manganese are trace elements whose concentrations are affected by the oxidation-reduction state of the 

ground water. Precipitation of minerals containing iron or 

manganese may cause orange, brown, or black staining of 

surfaces. Iron was detected in less than half of the samples, but 

two wells had concentrations above the SMCL-CA (table 11). 

Concentrations of manganese in SOSA wells were typically 

very low, but three wells had concentrations above the SMCLCA.

Arsenic, iron, and chromium occur in different species 

depending on the oxidation-reduction state of the ground 

water. The oxidized and reduced species have different solubilities in ground water and may have different effects on human 

health. The relative proportions of the oxidized and reduced 

species of each element also are used to aid in interpretation 

of the oxidation–reduction state of the aquifer. Concentrations 

of total arsenic, iron, and chromium, and the concentrations 

of either the reduced or the oxidized species of each element 

are reported in table 12. The concentration of the other species 

can be calculated by difference. The concentrations of arsenic, 

iron, and chromium reported in table 12 may be different than 

those reported in table 11 because different analytical methods 

were used (see Appendix). The concentrations reported in 

table 11 are considered to be more accurate.

Inorganic Tracer Constituents

Stable isotope ratios, tritium and carbon-14 activities, 

and noble gas concentrations can be used as tracers of natural processes affecting ground-water composition. Hydrogen 

and oxygen stable isotope ratios of water (table 13) can aid in 

interpretation of ground-water recharge sources. The stable 

isotope ratios of water depend on the altitude, latitude, and 

temperature of precipitation and on the extent of evaporation 

of surface water or soil water. Noble gas concentrations can be 

used to aid in interpretation of ground-water recharge sources 

because the concentrations of the different noble gases depend 

on water temperature. Noble gas analyses were not completed 

in time for inclusion in this report; they will be presented in a 

subsequent report.

Tritium and carbon-14 activities (table 13), and helium 

isotope ratios can provide information about the age of the 

ground water. Tritium is a radioactive isotope of hydrogen 

that is incorporated into the water molecule. Low levels of 

tritium are continuously produced by cosmic ray bombardment of water in the atmosphere, and a large amount of tritium 

was produced by atmospheric testing of nuclear weapons 

between 1952 and 1963. Thus, concentrations of tritium 

above background generally indicate the presence of water 

recharged since the early 1950s. Helium isotope ratios can be 

used in conjunction with tritium concentrations to estimate 

ages for young ground water. Helium isotope analyses were 

not completed in time for inclusion in this report; they will be 

presented in a subsequent report.

Carbon-14 (table 13) is a radioactive isotope of carbon 

that is incorporated into dissolved carbonate species in water. 

Low levels of carbon-14 are continuously produced by cosmic 

ray bombardment of nitrogen in the atmosphere. Because carbon-14 decays with a half-life of approximately 5,700 years, 

low activities of carbon-14 relative to modern values generally 

indicate presence of ground water that is at least several thousand years old, or has interacted with carbonate-rich sediments 

in the aquifer.

Of the inorganic tracer constituents analyzed for this 

study, the only one with a health-based threshold is tritium. All 

measured tritium activities in samples from SOSA wells were 

less than one one-thousandth of the MCL-CA (table 13).

Radioactive Constituents

Radioactivity is the release of energy or energetic 

particles during changes in the structure of the nucleus of an 

atom. Most of the radioactivity in ground water comes from 

decay of naturally-occurring isotopes of uranium and thorium 

that are present in minerals in the sediments or fractured rocks 

of the aquifer. Both uranium and thorium decay in a series of 

steps, eventually forming stable isotopes of lead. Radium-226, 

radium-228, and radon-222 are radioactive isotopes formed 

during the uranium or thorium decay series. In each step in 

the decay series, one radioactive element turns into a different radioactive element by emitting an alpha or a beta particle 

from its nucleus. For example, radium-226 emits an alpha particle and therefore turns into radon-222. Radium-228 decays 

to form actinium-228 by emission of a beta particle. The alpha 

and beta particles emitted during radioactive decay are hazardous to human health because these energetic particles may 

damage cells. Radiation damage to cell DNA may increase the 

risk of getting cancer.

Activity is often used instead of concentration for 

reporting the presence of radioactive constituents. Activity of 

radioactive constituents in ground water is measured in units 

of picocuries per liter (pCi/L), and one picocurie is approximately equal to two atoms decaying per minute. The number 

of atoms decaying is equal to the number of alpha or beta 

particles emitted.

 The seven SOSA samples analyzed for radioactive 

constituents had activities of radium and of gross alpha and 

beta emitters less than established health-based standards 

(table 14). Activities of radon-222 in samples from four wells 

were above the proposed MCL-US of 300 pCi/L, although 

only one sample had an activity that was also above the 

proposed alternative MCL-US of 4,000 pCi/L. The alternative MCL-US will apply if the State or local water agency has 

an approved multimedia mitigation program to address radon 

12 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
levels in indoor air (U.S. Environmental Protection Agency, 

1999a).

Microbial Indicators

Water is disinfected during drinking-water treatment to 

prevent diseases that may be spread by water-borne microbial constituents derived from human or animal wastes. The 

specific viruses and bacteria responsible for diseases generally 

are not measured because routine analytical methods are not 

available. Measurements are made of more easily analyzed 

microbial constituents that serve as indicators of the presence 

of human or animal waste in water. Drinking-water purveyors respond to detections of microbial indicators by applying 

additional disinfection to the water.

Samples from seven SOSA wells were analyzed for 

microbial indicators. No samples contained the viral indicators F-specific and somatic coliphage and none contained the 

bacterial indicator Escherichia coli (E. coli), but there were 

three detections of low levels of the bacterial indicator total 

coliforms (table 15). The threshold for total coliforms is based 

on recurring detections; thus, the detections reported here do 

not necessary constitute an exceedance of the MCL-US.

Future Work

Future work will interpret the data presented in this 

report using a variety of statistical, qualitative, and quantitative 

approaches to assess the natural and human factors affecting ground-water quality. Water-quality data contained in the 

CDPH and USGS NWIS databases, and water-quality data 

available from other State and local water agencies will be 

compiled, evaluated, and used to complement the data presented in this report.

Summary

Ground-water quality in the approximately 1,800-squaremile Southern Sierra study unit (SOSA) was investigated in 

June 2006 as part of the Statewide Basin Assessment Project of Groundwater Ambient Monitoring and Assessment 

(GAMA) Program. The California State Water Resources 

Control Board (SWRCB), in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National 

Laboratory, is implementing the GAMA Program (http://www.

waterboards.ca.gov/gama/). The Statewide Basin Assessment Project was designed by the SWRCB and the USGS 

in response to the Groundwater Quality Monitoring Act of 

2001 (Belitz and others, 2003; State Water Resources Control 

Board, 2003). The project is a comprehensive assessment 

of statewide ground-water quality designed to identify and 

characterize risks to ground-water resources, and to increase 

the availability of information about ground-water quality to 

the public. SOSA was the eleventh study unit sampled as part 

of the project.

SOSA is in the southern portion of the Sierra Nevada 

hydrogeologic province and includes within it six small 

ground-water basins defined by the California Department of 

Water Resources (California Department of Water Resources, 

2003). The SOSA study included assessment of the groundwater quality from fifty wells in Kern and Tulare Counties. 

Thirty-five of the wells were selected using a randomized 

grid approach to achieve statistically unbiased representation of ground water used for public drinking-water supplies. Fifteen of the wells were selected to provide additional 

sampling density to aid in understanding processes affecting 

ground-water quality. Ground-water samples were analyzed 

for VOCs, pesticides and pesticide degradates, pharmaceutical 

compounds, wastewater-indicator compounds, nutrients, major 

and minor ions, trace elements, radioactivity, and microbial 

indicators. Naturally occurring isotopes (stable isotopes of 

hydrogen, oxygen, and carbon, and activities of tritium and 

carbon-14) and dissolved noble gases also were measured to 

provide a data set that will be used to help interpret the source 

and age of the sampled ground water. This report describes 

the hydrogeologic setting of the SOSA region, details the 

sampling, analytical, and quality assurance used in the study, 

and presents the results of the chemical and microbial analyses 

made of the ground-water samples collected during June 2006.

Quality-control samples (blanks, replicates, and samples 

for matrix spikes) were collected at 10 to 18 percent of the 

wells, and the results for these samples were used to evaluate 

the quality of the data for the ground-water samples. Assessment of the quality-control information resulted in censoring 

of less than 0.2 percent of the ground-water quality data.

This study did not attempt to evaluate the quality of water 

delivered to consumers; after withdrawal from the ground, 

water typically is treated, disinfected, and blended with other 

waters to maintain acceptable water quality. Regulatory 

thresholds apply to treated water that is served to the consumer, not to raw ground water. However, to provide some 

context for the results, concentrations of constituents measured 

in the raw ground water were compared with health-based 

thresholds established by the U.S. Environmental Protection 

Agency (USEPA) and California Department of Public Health 

(CDPH).

All detections of VOCs and pesticides were below healthbased thresholds, and most were less than one one-hundredth 

of the threshold values. All detections of perchlorate, nitrate, 

and radioactive constituents were below established thresholds. Only one constituent, arsenic, was detected above a 

maximum contaminant level (MCL-US), although radon-222 

was detected above the proposed MCL-US. Boron and 1,2,3-

TCP each had one detection above the CDPH notification level 

(NL-CA). Total dissolved solids, specific conductance, pH, 

iron, and manganese were detected at concentrations above 

secondary maximum contaminant levels (SMCL-CAs), nonenforceable thresholds set for aesthetic concerns, in samples 

from several of the wells. Future work will interpret the data 

Summary 13
presented in this report using a variety of statistical, qualitative, and quantitative approaches to assess the natural and 

human factors affecting ground-water quality.

References Cited

American Public Health Association, 1998, Standard methods 

for the examination of water and wastewater (20th ed.): 

Washington, D.C., American Public Health Association, 

American Water Works Association, and Water Environment Federation, p. 3-37–3-43.

American Society for Testing and Materials, 1998, Annual 

book of ASTM standards—water and environmental technology: Philadelphia, Pennsylvania, American Society for 

Testing and Materials, v. 11.02 (Water II), p. 664–666.

Appelo, C.A.J., and Postma, D., 2005, Geochemistry, groundwater, and pollution (2nd ed.): Leiden, A.A. Balkema Publishers, 649 p.

Ball, J.W., and McCleskey, R.B., 2003, A new cationexchange method for accurate field speciation of hexavalent 

chromium: U.S. Geological Survey Water-Resources Investigations Report 03-4018, 17 p.

Ball, J.W., and McCleskey, R.B., 2003, A new cationexchange method for accurate field speciation of hexavalent 

chromium: Talanta, v. 61, p. 305–313.

Belitz, K., Dubrovsky, N.M., Burow, K.R., Jurgens, B., and 

Johnson, T., 2003, Framework for a ground-water quality 

monitoring and assessment program for California: U.S. 

Geological Survey Water-Resources Investigations Report 

03-4166, 78 p.

Bennett, G.L., V, Belitz, K., and Milby Dawson, B.J., 2006, 

California GAMA Program—Ground-water quality data 

in the northern San Joaquin basin study unit, 2005: U.S. 

Geological Survey Data Series 196, 122 p.

Brenton, R.W., and Arnett, T.L., 1993, Methods of analysis by 

the U.S. Geological Survey National Water-Quality Laboratory—Determination of dissolved organic carbon by UVpromoted persulfate oxidation and infrared spectrometry: 

U.S. Geological Survey Open-File Report 92-480, 12 p.

Bushon, R.N., 2003, Fecal indicator viruses: U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chap. A7.2, accessed June 28, 2007 at http://pubs.water.

usgs.gov/twri9A7.2/

California Department of Health Services, 2007a, California 

Code of Regulations. Title 22, Division 4 Environmental 

Health, Chapter 15 Domestic Water Quality and Monitoring 

Regulations. Register 2007, No. 4 (current as of January 26, 

2007), http://ccr.oal.ca.gov/ (accessed February 10, 2007)

California Department of Health Services, 2007b, Chemical 

contaminants in drinking water, http://www.dhs.ca.gov/ps/

ddwem/chemicals/default.htm (accessed March 31, 2007).

California Department of Water Resources, 2003, California’s 

groundwater: California Department of Water Resources 

Bulletin 118, 246 p, http://www.groundwater.water.ca.gov/

bulletin118/

California Department of Water Resources, 2006a, California 

Department of Water Resources Bulletin 118, individual 

basin descriptions, Cummings Valley, http://www.dpla2.

water.ca.gov/publications/groundwater/bulletin118/basins/

pdfs_desc/5-27.pdf (accessed December 1, 2006).

California Department of Water Resources, 2006b, California 

Department of Water Resources Bulletin 118, individual 

basin descriptions, Brite Valley, http://www.dpla2.water.

ca.gov/publications/groundwater/bulletin118/basins/pdfs_

desc/5-80.pdf (accessed December 1, 2006).

California Department of Water Resource, 2006c, California 

Department of Water Resources Bulletin 118, individual 

basin descriptions, Tehachapi Valley West, http://www.

dpla2.water.ca.gov/publications/groundwater/bulletin118/

basins/pdfs_desc/5-28.pdf (accessed December 1, 2006).

California Department of Water Resources, 2006d, California 

Department of Water Resources Bulletin 118, individual 

basin descriptions, Tehachapi Valley East, http://www.

dpla2.water.ca.gov/publications/groundwater/bulletin118/

basins/pdfs_desc/6-45.pdf (accessed December 1, 2006).

California Department of Water Resources, 2006e, California 

Department of Water Resources, individual basin descriptions, Kern River Valley, http://www.dpla2.water.ca.gov/

publications/groundwater/bulletin118/basins/pdfs_desc/5-

25.pdf (accessed December 1, 2006).

California Department of Water Resources, 2007, California Data Exchange Center, California Department of 

Water Resources, Division of Flood Management, average 

monthly precipitation data for the Tehachapi (THH) and Isabella Dam (ISB) stations, http://cdec.water.ca.gov (accessed 

February 10, 2007)

Childress, C.J.O., Foreman, W.T., Connor, B.F., and Maloney, T.J., 1999, New reporting procedures based on longterm method detection levels and some considerations for 

interpretations of water-quality data provided by the U.S. 

Geological Survey National Water Quality Laboratory: U.S. 

Geological Survey Open-File Report 99-193, 19 p.

14 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Connor, B.F., Rose, D.L., Noriega, M.C., Murtagh, L.K., and 

Abney, S.R., 1998, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of 86 volatile organic compounds in water by gas 

chromatography/mass spectrometry, including detections 

less than reporting limits: U.S. Geological Survey OpenFile Report 97-829, 78 p.

Coplen, T.B., Wildman, J.D., and Chen, J., 1991, Improvements in the gaseous hydrogen-water equilibrium technique 

for hydrogen isotope analysis: Analytical Chemistry, v. 63, 

p. 910–912.

Coplen, T.B., 1994, Reporting of stable hydrogen, carbon, and 

oxygen isotopic abundances: Pure and Applied Chemistry, 

v. 66, p. 273–276.

Coplen, T.B., Hopple, J.A., Bohlke, J.K., Peiser, H.S., Rieder, 

S.E., Krouse, H.R., Rosman, K.J.R., Ding, T., Vocke, R.D., 

Jr., Revesz, K.M., Lamberty, A., Taylor, P., and DeBierve, 

P., 2002, Compilation of minimum and maximum isotope 

ratios of selected elements in naturally occurring terrestrial 

materials and reagents: U.S. Geological Survey WaterResources Investigations Report 01-4222, 98 p.

Dawson, B.J., Bennett, G.L., V, and Belitz, K., 2007, California GAMA Program: Ground-water quality data in the 

Southern Sacramento Valley study unit, California, 2005: 

U.S. Geological Survey Data Series.

Dibblee, T.W., Jr., and Louke, G.P., 1970, Geologic map of 

the Tehachapi quadrangle, Kern County, California: U.S. 

Geological Survey Miscellaneous geologic Investigations 

Map I-607, 8 p., 1 plate.

Dibblee, T.W., Jr., and Warne, A.H., 1970, Geologic map of 

the Cummings Mountain quadrangle, Kern County, California: U.S. Geological Survey Miscellaneous geologic 

Investigations Map I-611, 5 p., 1 plate.

Donahue, D.J., Linick, T.W., and Jull, A.J.T., 1990, Ratio and 

background corrections for accelerator mass spectrometry 

radiocarbon measurements: Radiocarbon, v. 32, p. 135–142.

Eaton, G.F., Hudson, G.B., and Moran, J.E., 2004, Tritiumhelium-3 age-dating of groundwater in the Livermore Valley 

of California: American Chemical Society ACS Symposium 

Series, v. 868, p. 235–245.

Epstein, S., and Mayeda, T.K., 1953, Variation of O-18 content of water from natural sources: Geochimica et Cosmochimica Acta, v. 4, p. 213–224.

Faires, L.M., 1993, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of metals in water by inductively coupled plasma-mass 

spectrometry: U.S. Geological Survey Open-File Report 

92-634, 28 p.

Fishman, M.J., and Friedman, L.C., 1989, Methods for 

determination of inorganic substances in water and fluvial 

sediments: U.S. Geological Survey Techniques of WaterResources Investigations, book 5, chap. A1, 545 p.

Fishman, M.J., 1993, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of inorganic and organic constituents in water and 

fluvial sediments: U.S. Geological Survey Open-File Report 

93-125, 217 p.

Firestone, R.B., Shirley, V.S., Baglin, C.M., Chu, S.Y.F., and 

Zipkin, J., 1996, Table of isotopes, 8th ed.: New York, John 

Wiley & Sons, 3168 p. http://ie.lbl.gov/toipdf/toi20.pdf

Garbarino, J.R., 1999, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory 

—Determination of dissolved arsenic, boron, lithium, selenium, strontium, thallium, and vanadium using inductively 

coupled plasma-mass spectrometry: U.S. Geological Survey 

Open-File Report 99-093, 31 p.

Garbarino, J.R., and Damrau, D.L., 2001, Methods of analysis 

by the U.S. Geological Survey National Water Quality Laboratory—Determination of organic plus inorganic mercury 

in filtered and unfiltered natural water with cold 

vapor –atomic fluorescence spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 01-4132, 

16 p.

Garbarino, J.R., Kanagy, J.R., and Cree, M.E., 2006, Determination of elements in natural-water, biota, sediment, and soil 

samples using collision/reaction cell inductively coupled 

plasma-mass spectrometry: U.S. Geological Survey Techniques and Methods, Book 5, Chap. B1, 88 p.

Gilliom, R.J., Barbash, J.E., Crawford, C.G., Hamilton, P.A., 

Martin, J.D., Nakagaki, N., Nowell, L.H., Scott, J.C., Stackelberg, P.E., Thelin, G.P., and Wolock, D.M., 2006, The 

quality of our nation’s waters—Pesticides in the nation’s 

streams and ground water, 1992–2001: U.S. Geological 

Survey Circular 1291, 172 p.

Grob, R.L, ed., 1995, Modern practice of gas chromatography 

(3rd ed.): New York, John Wiley & Sons, 888 p.

Hamlin, S.N., Belitz, K., Kraja, S., and Dawson, B.J., 2002, 

Ground-water quality in the Santa Ana watershed, California: Overview and data summary: U.S. Geological Survey 

Water-Resources Investigations Report 02-4243, 137 p.

Hautman, D.P., Munch, D.J., Eaton, A.D., and Haghani, 

A.W., 1999, Method 314.0 Determination of perchlorate in 

drinking water using ion chromatography, revision 1.0, U.S. 

Environmental Protection Agency, accessed June 22, 2004 

at http://www.epa.gov/safewater/methods/pdfs/met314.pdf

References Cited 15
Helsel, D.R., and Hirsch, R.M., 2002, Statistical methods in 

water resources: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 4, chap. A3, accessed 

June 28, 2007 at http://pubs.usgs.gov/twri/twri4a3/pdf/

twri4a3-new.pdf

Hutson, S.S., Barber, N.L., Kenny, J.F., Linsey, K.S., Lumia, 

D.S., and Maupin, M.A., 2004, Estimated use of water in 

the United States in 2000: U.S. Geological Survey Circular 

1268, 46 p.

Jull, A.J.T., Burr, G.S., McHargue, L.R., Lange, T.E., Lifton, 

N.A., Beck, J.W., Donahue, D.J., and Lal, D., 2004, New 

frontiers in dating of geological, paleoclimatic, and anthropological applications using accelerator mass spectrometric 

measurements of 14C and 10Be in diverse samples: Global 

and Planetary Change, v. 41, p. 309–323.

Kolpin, D.W., Furlong, E.T., Meyer, M.T., Thurman, E.M., 

Zaugg, S.D., Barber, L.B., and Buxton, H.T., 2002, Pharmaceuticals, hormones and other organic wastewater contaminants in U.S. streams, 1999–2000: Environmental Science 

& Technology, v. 36, no. 6, p. 1202–1211.

Koterba, M.T., Wilde, F.D., and Lapham, W.W., 1995, 

Ground-water data-collection protocols and procedures 

for the National Water-Quality Assessment Program—C 

ollection and documentation of water-quality samples and 

related data: U.S. Geological Survey Open-File Report 95-

399, 113 p.

Kulongoski, J.T., and Belitz, K., 2004, Ground-water ambient monitoring and assessment program: U.S. Geological 

Survey Fact Sheet 2004–3088.

Kulongoski, J.T., Belitz, K., and Dawson, B.J., 2006, Groundwater quality data in the North San Francisco Bay Hydrogeologic provinces, California, 2004—Results from the 

California Ground-Water Ambient Monitoring and Assessment (GAMA) Program: U.S. Geological Survey Data 

Series 167, 100 p.

Kulongoski, J.T., and Belitz, K., 2007, Ground-water quality 

data in the Monterey Bay and Salinas Valley Basins, California, 2005—Results from the California GAMA Program: 

U.S. Geological Survey Data Series DS–258, 84 p.

Lane, S.L., Flanagan, S., and Wilde, F.D., 2003, Selection of 

equipment for water sampling (ver. 2.0): U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chap. A2, accessed June 28, 2007 at http://pubs.water.

usgs.gov/twri9A2/

Lewis, M.E., 2006, Dissolved oxygen (ver. 2.1): U.S. Geological Survey Techniques of Water-Resources Investigations, 

book 9, chap. A6.2, accessed June 28, 2007 at http://pubs.

water.usgs.gov/twri9A6.2/

Lindley, C.E., Stewart, J.T., and Sandstrom, M.W., 1996, 

Determination of low concentrations of acetochlor in water 

by automated solid-phase extraction and gas chromatography with mass selective detection: Journal of AOAC 

International, v. 79, no. 4, p. 962–966.

Madsen, J.E., Sandstrom, M.W., and Zaugg, S.D., 2003, 

Methods of analysis by the U.S. Geological Survey National 

Water Quality Laboratory—A method supplement for the 

determination of fipronil and degradates in water by gas 

chromatography/mass spectrometry: U.S. Geological Survey Open-File Report 02-462, 11 p.

Maloney, T.J., 2005, Quality management system, U.S. Geological Survey National Water Quality Laboratory: U.S. 

Geological Survey Open-File Report 2005–1263, http://

pubs.usgs.gov/of/2005/1263/pdf/OFR2005-1263.pdf

McCleskey, R.B., Nordstrom, D.K., and Ball, J.W., 2003, 

Metal interferences and their removal prior to the determination of As(T) and As(III) in acid mine waters by hydride 

generation atomic absorption spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 03–4117.

McLain, B., 1993, Methods of analysis by the U.S. Geological 

Survey National Water Quality Laboratory—determination 

of chromium in water by graphite furnace atomic absorption spectrophotometry: U.S. Geological Survey Open-File 

Report 93-449, 16 p.

Michael, E.D., and McCann, D.L., 1962, Geology ground 

water survey, Tehachapi Soil Conservation District, Kern 

County, California: Michael-McCann Associates Engineering Geology, 168 p., 13 appendices.

Moran, J.E., Hudson, G.B., Eaton, G.F., and Leif, R., 2002, A 

contamination vulnerability assessment for the LivermoreAmador and Niles Cone Groundwater Basins UCRL-AR148831, 25 p.

Myers, D.N., 2004, Fecal indicator bacteria (ver. 1.2): U.S. 

Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A7.1, accessed June 28, 2007 at 

http://pubs.water.usgs.gov/twri9A7.1/

Patton, C.J., and Kryskalla, J.R., 2003, Methods of analysis 

by the U.S. Geological Survey National Water Quality 

Laboratory—Evaluation of alkaline persulfate digestion 

as an alternative to Kjeldahl digestion for determination of 

total and dissolved nitrogen and phosphorous in water: U.S. 

Geological Survey Water-Resources Investigations Report 

03–4174, 33 p.

Pirkey, K.D., and Glodt, S.R., 1998, Quality control at the U.S. 

Geological Survey National Water Quality Laboratory: U.S. 

Geological Survey Fact-Sheet FS-026-98, 4 p., http://pubs.

er.usgs.gov/usgspubs/fs/fs02698

16 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Radtke, D.B., Davis, J.V., and Wilde, F.D., 2005, Specific 

electrical conductance (ver. 1.2): U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 9, 

chap. A6.3, accessed June 28, 2007 at http://pubs.water.

usgs.gov/twri9A6.3/

Rose, D.L., and Sandstrom, M.W., 2003, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—Determination of gasoline oxygenates, 

selected degradates, and BTEX in water by heated purge 

and trap/gas chromatography/mass spectrometry: U.S. 

Geological Survey Water-Resources Investigations Report 

03–4079, 31 p.

Rounds, S.A., 2006, Alkalinity and acid neutralizing capacity (ver. 3): U.S. Geological Survey Techniques of WaterResources Investigations, book 9, chap. A6.6, accessed June 

28, 2007 at http://pubs.water.usgs.gov/twri9A6.6/

Sandstrom, M.W., Stroppel, M.E., Foreman, W.T., and Schroeder, M.P., 2001, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory—determination of moderate-use pesticides and selected degradates in 

water by C-18 solid-phase extraction and gas chromatography/mass spectrometry: U.S. Geological Survey WaterResources Investigations Report 01-4098, 70 p.

Scott, J.C., 1990, Computerized stratified random site selection approaches for design of a ground-water quality sampling network: U.S. Geological Survey Water-Resources 

Investigations Report 90-4101, 109 p.

Shelton, J.L., Burow, K.R., Belitz, K., Dubrovsky, N.M., Land, 

M.T., and Gronberg, J.M., 2001, Low-level volatile organic 

compounds in active public supply wells as ground-water 

tracers in the Los Angeles physiographic basin, California, 

2000: U.S. Geological Survey Water-Resources Investigations Report 01-4188, 29 p.

State Water Resources Control Board, 2003, A comprehensive 

groundwater quality monitoring program for California: 

Assembly Bill 599 Report to the Governor and Legislature, 

March 2003, 100 p. http://www.waterboards.ca.gov/gama/

docs/final_ab_599_rpt_to_legis_7_31_03.pdf

Stein, R.S., and Thatcher, W., 1981, Seismic and aseismic 

deformation associated with the 1952 Kern County, California, earthquake and relationship to the Quaternary history 

of the White Wolf fault: Journal of Geophysical Research, 

v. 86, no. B6, p. 4913–4928.

Stookey, L.L., 1970, FerroZine - a new spectrophotometric 

reagent for iron: Analytical Chemistry, v. 42, p. 779–781.

Tehachapi-Cummings County Water District, 2004, Thirtieth 

Annual Watermaster Report for Cummings Basin, 14 p.

Tehachapi-Cummings County Water District , 2004, ThirtyFirst Annual Watermaster Report for Tehachapi Basin, 71 p.

Thatcher, L.L., Janzer, V.J., and Edwards, K.W., 1977, Methods for the determination of radioactive substances in water: 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 5, chap. A5, 95 p.

Timme, P.J., 1995, National Water Quality Laboratory 1995 

services catalog: U.S. Geological Survey Open-File Report 

95-352, 120 p.

To, T.B., Nordstrom, D.K., Cunningham, K.M., Ball, J.W., and 

McCleskey, R.B., 1998, New method for the direct determination of dissolved Fe(III) concentration in acid mine 

waters: Environmental Science and Technology, v. 33, 

p. 807–813.

U.S. Environmental Protection Agency, 1980, Prescribed procedures for measurement of radioactivity in drinking water: 

U.S. Environmental Protection Agency EPA-600-4-80-032.

U.S. Environmental Protection Agency, 1995, Method 524.2, 

Measurement of purgeable organic compounds in water by 

capillary column gas chromatography/mass spectrometry: 

U.S. Environmental Protection Agency EPA/600/R-95-131.

U.S. Environmental Protection Agency, 1996, Method 

8270C—semivolatile organic compounds by gas chromatography/mass spectrometry, revision 3.

U.S. Environmental Protection Agency, 1999a, National 

Primary Drinking Water Regulations, Radon-222: Federal 

Register, v. 64, no. 211, p. 59245–59294.

U.S. Environmental Protection Agency, 1999b, Method 1625 

revision B—Semivolatile organic compounds by isotope 

dilution GC/MS, 40 CFR Part 136, Appendix A.

U.S. Environmental Protection Agency, 2001, Method 

1601—Male-specific (F+) and somatic Coliphage in water 

by two-step enrichment procedure—April 2000 Draft: U.S. 

Environmental Protection Agency EPA 821-R-00-009.

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): U.S. Environmental Protection Agency 

EPA 821-R-02-024.

U.S. Environmental Protection Agency, 2002a, Guidelines for 

establishing procedures for the analysis of pollutants: U.S. 

Code of Federal Regulations, Title 40, 136 p.

U.S. Environmental Protection Agency, 2004, National primary drinking water regulations—Analytical method for 

uranium: U.S. Code of Federal Regulations, Title 40, part 

141, revised as of June 2004, p. 31008-31013.

References Cited 17
U.S. Environmental Protection Agency, 2006, 2006 Edition 

of the Drinking Water Standards and Health Advisories, 

updated August 2006: U.S. Environmental Protection 

Agency, Office of Water EPA 822-R-06-013, http://www.

epa.gov/waterscience/criteria/drinking/dwstandards.pdf

U.S. Geological Survey, variously dated, National field manual 

for the collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chap. A1–A9, http://water.usgs.gov/owq/FieldManual/

Weiss, R.F., 1968, Piggyback sampler for dissolved gas studies 

on sealed water samples: Deep Sea Research, v. 15, 

p. 721–735.

Wilde, F.D., 2006, Temperature (ver. 2): U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chap. A6.1, accessed June 28, 2007 at http://pubs.water.

usgs.gov/twri9A6.1/

Wilde, F.D., ed., 2004, Cleaning of equipment for water 

sampling (ver. 2.0): U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 9, chap. A3, accessed 

June 28, 2007 at http://pubs.water.usgs.gov/twri9A3/

Wilde, F.D., Busenberg, E., and Radtke, D.B., 2006, pH 

(ver. 1.3): U.S. Geological Survey Techniques of WaterResources Investigations, book 9, chap. A6.4, accessed June 

28, 2007 at http://pubs.water.usgs.gov/twri9A6.4/

Wilde, F.D., and Radtke, D.B., 2005, General information 

and guidelines (ver. 1.2): U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chap. 

A6.0, accessed June 28, 2007 at http://pubs.water.usgs.

gov/twri9A6.0/

Wilde, F.D., Radtke, D.B., Gibs, J., and Iwatsubo, R.T., 1999, 

Collection of water samples: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 9, 

chap. A4, accessed June 28, 2007 at http://pubs.water.usgs.

gov/twri9A4/

Wilde, F.D., Radtke, D.B., Gibs, J., and Iwatsubo, R.T., 2004, 

Processing of water samples: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 9, 

chap. A5, accessed June 28, 2007 at http://pubs.water.usgs.

gov/twri9A5/

Wright, M.T., Belitz, K., and Burton, C.A., 2005, California 

GAMA program: ground-water quality in the San Diego 

drainages hydrologic province, California, 2004: U.S. 

Geological Survey Data Series 129, 91 p.

Zaugg, S.D., Sandstrom, M.W., Smith, S.G., and Fehlberg, 

K.M., 1995, Methods of analysis by the U.S. Geological 

Survey National Water Quality Laboratory—Determination 

of pesticides in water by C-18 solid-phase extraction and 

capillary-column gas chromatography/mass spectrometry: 

U.S. Geological Survey Open-File Report 95-181, 60 p.

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 polystyrene 

divinylbenzene solid-phase extraction and capillary-column 

gas chromatography/mass spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 01-4186, 

37 p.

18  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 1. Identification, sampling, and construction information for wells sampled for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006—Continued. 

[SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; ft, foot; LSD, land surface datum; NAVD88, North 

American Vertical Datum 1988; na, not available]

GAMA 

well 

identification 

 number

Sampling information Construction information

Date 

(m/dd/yyyy)

Sampling 

schedule1

Elevation of 

LSD 

(ft above 

NAVD88)

2

Well depth

(ft below 

LSD)

Top 

perforation

(ft below 

LSD)

Bottom 

perforation

(ft below LSD)

Grid Wells

SOSA-01 6/5/2006 Fast 5,049 na na na

SOSA-02 6/6/2006 Fast 2,822 102 54 102

SOSA-03 6/6/2006 Slow 2,606 270 130 270

SOSA-04 6/6/2006 Fast 3,333 540 300 540

SOSA-05 6/7/2006 Fast 2,940 470 370 470

SOSA-06 6/7/2006 Fast 3,245 580 300 580

SOSA-07 6/7/2006 Slow 2,800 70 na na

SOSA-08 6/7/2006 Fast 3,770 700 300 700

SOSA-09 6/8/2006 Fast 3,840 300 60 300

SOSA-10 6/8/2006 Slow 2,720 174 90 174

SOSA-11 6/8/2006 Fast 4,335 332 50 332

SOSA-12 6/12/2006 Fast 3,000 na na na

SOSA-13 6/12/2006 Slow 4,010 520 280 510

SOSA-14 6/12/2006 Fast 2,600 305 150 195

SOSA-15 6/12/2006 Intermediate 5,060 na na na

SOSA-16 6/13/2006 Fast 2,549 na na na

SOSA-17 6/13/20063 Fast 3,330 150 20 150

SOSA-18 6/13/2006 Fast 3,025 na na na

SOSA-19 6/13/2006 Fast 3,045 na na na

SOSA-20 6/14/20063 Fast 2,964 165 140 165

SOSA-21 6/14/2006 Fast 2,671 na na na

SOSA-22 6/15/2006 Intermediate 7,200 na na na

SOSA-23 6/19/2006 Fast 3,845 460 200 460

SOSA-24 6/19/2006 Fast 4,226 350 243 350

SOSA-25 6/19/2006 Fast 4,124 180 84 180

SOSA-26 6/20/2006 Fast 4,633 490 140 490

SOSA-27 6/20/2006 Fast 4,094 600 140 400

SOSA-28 6/20/2006 Fast 3,914 200 80 200

SOSA-29 6/21/2006 Fast 3,533 31 23 27

SOSA-30 6/29/2006 Fast 2,770 375 220 375

SOSA-31 6/29/2006 Fast 2,650 120 78 120

SOSA-32 6/29/2006 Fast 4,180 400 200 400

SOSA-33 6/30/2006 Fast 3,100 195 115 195

SOSA-34 6/30/2006 Fast 3,970 180 84 174

SOSA-35 6/30/2006 Intermediate 4,260 na na na

Table 1. Identification, sampling, and construction information for wells sampled for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006. 

[SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; ft, foot; LSD, land surface datum; NAVD88, North American 

Vertical Datum 1988; na, not available]

Tables 19
Table 1. Identification, sampling, and construction information for wells sampled for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006—Continued. 

[SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; ft, foot; LSD, land surface datum; NAVD88, North 

American Vertical Datum 1988; na, not available]

GAMA 

well 

identification 

 number

Sampling information Construction information

Date 

(m/dd/yyyy)

Sampling 

schedule1

Elevation of 

LSD 

(ft above 

NAVD88)

2

Well depth

(ft below 

LSD)

Top 

perforation

(ft below 

LSD)

Bottom 

perforation

(ft below LSD)

Flow-path wells

SOSAFP-01 6/5/2006 Intermediate 4,029 546 267 546

SOSAFP-02 6/5/2006 Slow 2,640 55 10 55

SOSAFP-03 6/5/2006 Intermediate 4,072 604 400 590

SOSAFP-04 6/8/2006 Intermediate 3,940 290 50 285

SOSAFP-05 6/13/2006 Slow 4,040 480 180 480

SOSAFP-06 6/14/2006 Slow 4,045 420 na na

SOSAFP-07 6/22/2006 Intermediate 3,862 472 202 472

SOSAFP-08 6/26/2006 Intermediate 3,840 402 54 396

SOSAFP-09 6/26/2006 Intermediate 3,850 300 na na

SOSAFP-10 6/26/2006 Intermediate 3,820 357 119 na

SOSAFP-11 6/27/2006 Intermediate 3,850 300 na na

SOSAFP-12 6/27/2006 Intermediate 3,838 550 na na

SOSAFP-13 6/28/2006 Intermediate 4,060 478 212 478

SOSAFP-14 6/28/2006 Intermediate 4,055 500 180 500

SOSAFP-15 6/28/2006 Intermediate 3,980 294 114 288

1

Sampling schedules are described in table 2.

2

Land-surface datum (LSD) is a datum plane that is approximately at land surface at each well. The elevation of the LSD is described in feet above the 

North American Vertical Datum 1988.

3

Also sampled 6/29/2006. 

20 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 2. Classes of chemical and microbial constituents and water-quality indicators collected for the slow, intermediate, and fast 

well sampling schedules in the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 

2006.

Analyte classes Analyte 

list table

Slow 

schedule

Intermediate 

schedule

Fast 

schedule

Water-quality indicators

Dissolved oxygen, temperature, specific conductance X X X

pH, alkalinity X X

Turbidity X

Organic constituents

Volatile organic compounds 3A X X X

Gasoline additives and oxygenates 3B X X X

Pesticides and pesticide degredates 3C X X X

Pharmaceutical compounds 3D X X X

Wastewater-indicator compounds 3E X1

Constituents of special interest

Perchlorate 3F X X X

N-nitrosodimethylamine (NDMA) 3F X X

1,2,3-Trichloropropane 3F X X

Inorganic constituents

Nutrients and dissolved organic carbon 3G X X

Major and minor ions and trace elements 3H X X

Chromium abundance and speciation 3I X X X

Arsenic and iron abundances and speciation 3I X X

Stable isotopes

Stable isotopes of hydrogen and oxygen in water 3J X X X

Stable isotopes of carbon and carbon-14 abundance 3J X X

Radioactivity and noble gases

Tritium 3J X X

Tritium and noble gases 3K X X X

Radium isotopes 3J X

Radon-222 3J X

Gross alpha and beta radiation 3J X

Microbial constituents

Bacterial indicators 3L X

Viral indicators 3L X 1

Only 6 of the 14 intermediate wells.

Tables 21
Table 3A. Volatile organic compounds and gasoline additives, primary uses or sources, comparative thresholds, and reporting 

information for the USGS National Water Quality Laboratory schedule 2020—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory 

reporting level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum 

contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health 

notification level; RSD5-US, U.S. Environmental Protection Agency risk specific dose at a risk-specific factor of 10-5; THM, trihalomethane; D, detected in 

ground-water samples (table 5); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

Acetone Solvent 81552 67-64-1 6 na na —

Acrylonitrile Organic synthesis 34215 107-13-1 0.8 RSD5-US 0.6 —

Benzene Gasoline hydrocarbon 34030 71-43-2 0.021 MCL-CA 1 —

Bromobenzene Solvent 81555 108-86-1 0.028 na na —

Bromochloromethane Fire retardant 77297 74-97-5 0.12 HAL-US 90 —

Bromodichloromethane Disinfection by-product 

(THM)

32101 75-27-4 0.028 MCL-US 2

80 —

Bromoform (Tribromomethane) Disinfection by-product 

(THM)

32104 75-25-2 0.10 MCL-US 2

80 —

2-Butanone (MEK, Methyl ethyl 

ketone)

Solvent 81595 78-93-3 2 HAL-US 4,000 —

n-Butylbenzene Gasoline hydrocarbon 77342 104-51-8 0.12 NL-CA 260 —

sec-Butylbenzene Gasoline hydrocarbon 77350 135-98-8 0.06 NL-CA 260 —

tert-Butylbenzene Gasoline hydrocarbon 77353 98-06-6 0.06 NL-CA 260 —

Carbon disulfide Organic synthesis 77041 75-15-0 0.038 NL-CA 160 —

Carbon tetrachloride (Tetrachloromethane)Solvent 32102 56-23-5 0.06 MCL-CA 0.5 D

Chlorobenzene Solvent 34301 108-90-7 0.028 MCL-CA 70 —

Chloroethane Solvent 34311 75-00-3 0.12 na na —

Chloroform (Trichloromethane) Disinfection by-product 

(THM)

32106 67-66-3 0.024 MCL-US 2

80 D

Chloromethane Refrigerant/organic synthesis34418 74-87-3 0.17 HAL-US 30 —

3-Chloro-1-propene Organic synthesis 78109 107-05-1 0.5 na na — (4)

2-Chlorotoluene Solvent 77275 95-49-8 0.04 NL-CA 140 —

4-Chlorotoluene Solvent 77277 106-43-4 0.05 NL-CA 140 —

Dibromochloromethane Disinfection by-product 

(THM)

32105 124-48-1 0.10 MCL-US 2

80 —

1,2-Dibromo-3-chloropropane 

(DBCP)

Fumigant 82625 96-12-8 0.51 MCL-US 0.2 —

1,2-Dibromoethane (EDB) Fumigant 77651 106-93-4 0.036 MCL-US 0.05 —

Dibromomethane Solvent 30217 74-95-3 0.050 na na —

1,2-Dichlorobenzene Solvent 34536 95-50-1 0.048 MCL-CA 600 D

1,3-Dichlorobenzene Solvent 34566 541-73-1 0.03 HAL-US 600 —

1,4-Dichlorobenzene Fumigant 34571 106-46-7 0.034 MCL-CA 5 —

trans-1,4-Dichloro-2-butene Organic synthesis 73547 110-57-6 0.70 na na —

Dichlorodifluoromethane (CFC12)

Refrigerant 34668 75-71-8 0.18 NL-CA 1,000 —(5)

1,1-Dichloroethane Solvent 34496 75-34-3 0.035 MCL-CA 5 —

1,2-Dichloroethane Solvent 32103 107-06-2 0.13 MCL-CA 0.5 —

1,1-Dichloroethene (DCE) Organic synthesis 34501 75-35-4 0.024 MCL-CA 6 —

cis-1,2-Dichloroethene Solvent 77093 156-59-2 0.024 MCL-CA 6 D

Table 3A. Volatile organic compounds and gasoline additives, primary uses or sources, comparative thresholds, and reporting 

information for the USGS National Water Quality Laboratory schedule 2020.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting 

level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant 

level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; 

RSD5-US, U.S. Environmental Protection Agency risk specific dose at a risk-specific factor of 10-5; THM, trihalomethane; D, detected in ground-water samples 

(table 5); na, not available; μg/L, micrograms per liter; —, not detected]

22 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3A. Volatile organic compounds and gasoline additives, primary uses or sources, comparative thresholds, and reporting 

information for the USGS National Water Quality Laboratory schedule 2020—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory 

reporting level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum 

contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health 

notification level; RSD5-US, U.S. Environmental Protection Agency risk specific dose at a risk-specific factor of 10-5; THM, trihalomethane; D, detected in 

ground-water samples (table 5); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

trans-1,2-Dichloroethene Solvent 34546 156-60-5 0.032 MCL-CA 10 —

Dichloromethane (Methylene 

chloride)

Solvent 34423 75-09-2 0.06 MCL-US 5 —(5)

1,2-Dichloropropane Fumigant 34541 78-87-5 0.029 MCL-US 5 D

1,3-Dichloropropane Fumigant 77173 142-28-9 0.06 na na —(4)

2,2-Dichloropropane Fumigant 77170 594-20-7 0.05 na na —

1,1-Dichloropropene Organic synthesis 77168 563-58-6 0.026 na na —(4)

cis-1,3-Dichloropropene Fumigant 34704 10061-01-5 0.05 RSD5-US 3

4 —

trans-1,3-Dichloropropene Fumigant 34699 10061-02-6 0.09 RSD5-US 3

4 —

Diethyl ether Solvent 81576 60-29-7 0.08 na na —

Diisopropyl ether (DIPE) Gasoline oxygenate 81577 108-20-3 0.10 na na —

Ethylbenzene Gasoline hydrocarbon 34371 100-41-4 0.030 MCL-CA 300 —

Ethyl tert-butyl ether (ETBE) Gasoline oxygenate 50004 637-92-3 0.030 na na —

Ethyl methacrylate Organic synthesis 73570 97-63-2 0.18 na na —

1-Ethyl-2-methylbenzene (o-Ethyl 

toluene)

Gasoline hydrocarbon 77220 611-14-3 0.06 na na —

Hexachlorobutadiene Organic synthesis 39702 87-68-3 0.14 RSD5-US 9 —

Hexachloroethane Solvent 34396 67-72-1 0.14 HAL-US 1 —

2-Hexanone (n-Butyl methyl 

ketone)

Solvent 77103 591-78-6 0.4 na na —

Isopropylbenzene (Cumene) Gasoline hydrocarbon 77223 98-82-8 0.038 NL-CA 770 —

4-Isopropyl-1-methylbenzene Gasoline hydrocarbon 77356 99-87-6 0.08 na na —

Methyl acrylate Organic synthesis 49991 96-33-3 1.0 na na —

Methyl acrylonitrile Organic synthesis 81593 126-98-7 0.40 na na —

Methyl bromide (Bromomethane) Fumigant 34413 74-83-9 0.33 HAL-US 10 —

Methyl tert-butyl ether (MTBE) Gasoline oxygenate 78032 1634-04-4 0.10 MCL-CA 13 D

Methyl iodide (Iodomethane) Organic synthesis 77424 74-88-4 0.50 na na —

Methyl isobutyl ketone (MIBK) Solvent 78133 108-10-1 0.37 NL-CA 120 —

Methyl methacrylate Organic synthesis 81597 80-62-6 0.20 na na —

Methyl tert-pentyl ether (tert-Amyl 

methyl ether, TAME)

Gasoline oxygenate 50005 994-05-8 0.04 na na —

Naphthalene Gasoline hydrocarbon 34696 91-20-3 0.52 NL-CA 17 —

n-Propylbenzene Solvent 77224 103-65-1 0.042 NL-CA 260 —

Styrene Gasoline hydrocarbon 77128 100-42-5 0.042 MCL-US 100 —

1,1,1,2-Tetrachloroethane Solvent 77562 630-20-6 0.03 HAL-US 70 —

1,1,2,2-Tetrachloroethane Solvent 34516 79-34-5 0.08 MCL-CA 1 —

Tetrachloroethene (PCE) Solvent 34475 127-18-4 0.030 MCL-US 5 D

Tetrahydrofuran Solvent 81607 109-99-9 1.2 na na —

1,2,3,4-Tetramethylbenzene Gasoline hydrocarbon 49999 488-23-3 0.14 na na —(5)

1,2,3,5-Tetramethylbenzene Gasoline hydrocarbon 50000 527-53-7 0.18 na na —(5)

Toluene Gasoline hydrocarbon 34010 108-88-3 0.02 MCL-CA 150 —

Tables 23
Table 3A. Volatile organic compounds and gasoline additives, primary uses or sources, comparative thresholds, and reporting 

information for the USGS National Water Quality Laboratory schedule 2020—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory 

reporting level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum 

contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health 

notification level; RSD5-US, U.S. Environmental Protection Agency risk specific dose at a risk-specific factor of 10-5; THM, trihalomethane; D, detected in 

ground-water samples (table 5); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

1,2,3-Trichlorobenzene Organic synthesis 77613 87-61-6 0.18 na na —(5`)

1,2,4-Trichlorobenzene Solvent 34551 120-82-1 0.12 MCL-CA 5 —

1,1,1-Trichloroethane (TCA) Solvent 34506 71-55-6 0.032 MCL-CA 200 —

1,1,2-Trichloroethane Solvent 34511 79-00-5 0.04 MCL-CA 5 —

Trichloroethene (TCE) Solvent 39180 79-01-6 0.038 MCL-US 5 D

Trichlorofluoromethane (CFC-11) Refrigerant 34488 75-69-4 0.08 MCL-CA 150 D

1,2,3-Trichloropropane (1,2,3-

TCP)

Solvent/organic synthesis 77443 96-18-4 0.18 NL-CA 0.005 —

1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113)Refrigerant 77652 76-13-1 0.038 MCL-CA 1,200 D

1,2,3-Trimethylbenzene Gasoline hydrocarbon 77221 526-73-8 0.09 na na —

1,2,4-Trimethylbenzene Gasoline hydrocarbon 77222 95-63-6 0.056 NL-CA 330 —

1,3,5-Trimethylbenzene Organic synthesis 77226 108-67-8 0.044 NL-CA 330 —

Vinyl bromide (Bromoethene) Fire retardant 50002 593-60-2 0.10 na na —

Vinyl chloride (Chloroethene) Organic synthesis 39175 75-01-4 0.08 MCL-CA 0.5 —

m- and p-Xylene Gasoline hydrocarbon 85795 108-38-3 / 

106-42-3

0.06 MCL-CA 1,750 — (4)

o-Xylene Gasoline hydrocarbon 77135 95-47-6 0.038 MCL-CA 1,750 —

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is lower 

than the MCL-US or no MCL-US exists.

2

The MCL-US thresholds for trihalomethanes is the sum of chloroform, bromoform, bromodichloromethane, and dibromochloromethane.

3

The RSD5 threshold for 1,3-dichloropropene is the sum of its isomers (cis and trans).

4

The median matrix-spike recovery was greater than 130 percent.

5

The median matrix-spike recovery was less than 70 percent. Low recoveries may indicate that the compound might not have been detected in some samples 

if it was present at very low concentrations.

6

The preferred method for 1,2,3-Trichloropropane is MWH (table 3F).

24 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3B. Gasoline oxygenates and degradates, primary uses or sources, comparative thresholds, and reporting information for the 

USGS National Water Quality Laboratory schedule 4024.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; 

D, detected in ground-water samples (table 5); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

 code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

Acetone Degradate 81552 67-64-1 1.2 na na —

tert-Amyl alcohol Oxygenate 77073 75-85-4 1.0 na na —

tert-Butyl alcohol (TBA) Degradate 77035 75-65-0 1 NL-CA 12 —

Diisopropyl ether Oxygenate 81577 108-20-3 0.06 na na —

Ethyl tert-butyl ether (ETBE) Oxygenate 50004 637-92-3 0.06 na na —

Methyl acetate Degradate 77032 79-20-9 0.43 na na —

Methyl tert-butyl ether (MTBE) Oxygenate 78032 1634-04-4 0.05 MCL-US 13 D

Methyl tert-pentyl ether Oxygenate 50005 994-05-8 0.05 na na —

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

Tables 25
Table 3C. Pesticides and pesticide degradates, primary uses or sources, comparative thresholds, and reporting information for the 

USGS National Water Quality Laboratory schedule 2003—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; RSD5-US, U.S. Environmental Protection Agency risk-specific 

dose at a risk factor of 10-5; D, detected in ground-water samples (table 6); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

Acetochlor Herbicide 49260 34256-82-1 0.006 na na —

Alachlor Herbicide 46342 15972-60-8 0.005 MCL-US 2 —

Atrazine Herbicide 39632 1912-24-9 0.007 MCL-CA 1 D

Azinphos-methyl Insecticide 82686 86-50-0 0.05 na na —

Azinphos-methyl-oxon Insecticide degradate 61635 961-22-8 0.042 na na —

Benfluralin Herbicide 82673 1861-40-1 0.01 na na —(2)

Carbaryl Insecticide 82680 63-25-2 0.041 RSD5-US 400 —

2-Chloro-2,6-diethylacetanilide Herbicide degradate 61618 6967-29-9 0.0065 na na —

4-Chloro-2-methylphenol Herbicide degradate 61633 1570-64-5 0.0050 na na —(2)

Chlorpyrifos Insecticide 38933 2921-88-2 0.005 HAL-US 2 —

Chlorpyrofos, oxygen analog Insecticide degradate 61636 5598-15-2 0.0562 na na —(2)

Cyfluthrin Insecticide 61585 68359-37-5 0.053 na na —(2)

Cypermethrin Insecticide 61586 52315-07-8 0.046 na na —(2)

Dacthal (DCPA) Herbicide 82682 1861-32-1 0.003 HAL-US 70 —

Deethylatrazine (2-Chloro-4-isopropylamino-6-amino-s-triazine)Herbicide degradate 04040 6190-65-4 0.014 na na D(2)

Desulfinylfipronil Insecticide degradate 62170 na 0.012 na na —

Desulfinylfipronil amide Insecticide degradate 62169 na 0.029 na na —

Diazinon Insecticide 39572 333-41-5 0.005 HAL-US 1 —

Diazinon, oxon Insecticide degradate 61638 962-58-3 0.006 na na —

3,4-Dichloroaniline Herbicide degradate 61625 95-76-1 0.0045 na na —

Dichlorvos Insecticide 38775 62-73-7 0.013 na na —(2)

Dicrotophos Insecticide 38454 141-66-2 0.0843 na na —(2)

Dieldrin Insecticide 39381 60-57-1 0.009 RSD5-US 0.02 —

2,6-Diethylaniline Herbicide degradate 82660 579-66-8 0.006 na na —

Dimethoate Insecticide 82662 60-51-5 0.0061 na na —(2)

Ethion Insecticide 82346 563-12-2 0.016 na na —

Ethion monoxon Insecticide degradate 61644 17356-42-2 0.021 na na —

2-Ethyl-6-methylaniline Herbicide degradate 61620 24549-06-2 0.010 na na —

Fenamiphos Insecticide 61591 22224-92-6 0.029 HAL-US 0.7 —

Fenamiphos sulfone Insecticide degradate 61645 31972-44-8 0.053 na na —

Fenamiphos sulfoxide Insecticide degradate 61646 31972-43-7 0.040 na na —

Fipronil Insecticide 62166 120068-37-3 0.016 na na —

Fipronil sulfide Insecticide degradate 62167 120067-83-6 0.013 na na D

Fipronil sulfone Insecticide degradate 62168 120068-36-2 0.024 na na —(2)

Fonofos Insecticide 04095 944-22-9 0.0053 HAL-US 10 —

Hexazinone Herbicide 04025 51235-04-2 0.026 HAL-US 400 —

Iprodione Fungicide 61593 36734-19-7 0.026 na na —

Isofenphos Insecticide 61594 25311-71-1 0.011 na na —

Malaoxon Insecticide degradate 61652 1634-78-2 0.039 na na —

Malathion Insecticide 39532 121-75-5 0.027 HAL-US 100 —

Metalaxyl Fungicide 61596 57837-19-1 0.0069 na na —

Methidathion Insecticide 61598 950-37-8 0.0087 na na —

Metolachlor Herbicide 39415 51218-45-2 0.006 HAL-US 700 —

Metribuzin Herbicide 82630 21087-64-9 0.028 HAL-US 70 —

Myclobutanil Fungicide 61599 88671-89-0 0.033 na na —

Table 3C. Pesticides and pesticide degradates, primary uses or sources, comparative thresholds, and reporting information for the 

USGS National Water Quality Laboratory schedule 2003.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting 

level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant 

level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; RSD5-US, U.S. Environmental Protection Agency risk-specific dose at a 

risk factor of 10-5; D, detected in ground-water samples (table 6); na, not available; μg/L, micrograms per liter; —, not detected]

26 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3C. Pesticides and pesticide degradates, primary uses or sources, comparative thresholds, and reporting information for the 

USGS National Water Quality Laboratory schedule 2003—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; RSD5-US, U.S. Environmental Protection Agency risk-specific 

dose at a risk factor of 10-5; D, detected in ground-water samples (table 6); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

1-Naphthol Insecticide degradate 49295 90-15-3 0.0882 na na — 2

Paraoxon-methyl Insecticide degradate 61664 950-35-6 0.019 na na — 2

Parathion-methyl Insecticide 82667 298-00-0 0.015 HAL-US 1 —

Pendimethalin Herbicide 82683 40487-42-1 0.022 na na —

cis-Permethrin Insecticide 82687 54774-45-7 0.006 na na —(2)

Phorate Insecticide 82664 298-02-2 0.055 na na —

Phorate oxon Insecticide degradate 61666 2600-69-3 0.027 na na —

Phosmet Insecticide 61601 732-11-6 0.0079 na na —(2)

Phosmet oxon Insecticide degradate 61668 3735-33-9 0.0511 na na —(2)

Prometon Herbicide 04037 1610-18-0 0.01 HAL-US 100 D

Prometryn Herbicide 04036 7287-19-6 0.0059 na na —

Pronamide (Propyzamide) Herbicide 82676 23950-58-5 0.004 RSD5-US 20 —

Simazine Herbicide 04035 122-34-9 0.005 MCL-US 4 D

Tebuthiuron Herbicide 82670 34014-18-1 0.016 HAL-US 500 —

Terbufos Insecticide 82675 13071-79-9 0.017 HAL-US 0.4 —

Terbufos oxon sulfone Insecticide degradate 61674 56070-15-6 0.045 na na —

Terbuthylazine Herbicide 04022 5915-41-3 0.0083 na na —

Trifluralin Herbicide 82661 1582-09-8 0.009 HAL-US 10 —

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

2

The median matrix-spike recovery was less than 70 percent. Low recoveries may indicate that the compound might not have been detected in some samples 

if it was present at very low concentrations.

Tables 27
Table 3D. Pharmaceutical compounds, primary uses or sources, comparative thresholds, and reporting information for the USGS 

National Water Quality Laboratory schedule 2080.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting level; D, detected in ground-water samples (table 7); na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type

Threshold 

value 

(μg/L)

Detection

Acetaminophen Analgesic 62000 103-90-2 0.024 na na —

Caffeine Stimulant 50305 58-08-2 0.015 na na —

Carbamazapine Anticonvulsant; analgesic; 

mood stabilizer

62793 298-46-4 0.018 na na D

Codeine Opiod narcotic 62003 76-57-3 0.022 na na —

Cotinine Nicotine metabolite 62005 486-56-6 0.028 na na —

Dehydronifedipine Antianginal metabolite 62004 67035-22-7 0.022 na na —

Diltiazem Antianginal; antihypertensive62008 42399-41-7 0.018 na na —(1)

1,7-Dimethylxanthine Caffeine metabolite 62030 611-59-6 0.021 na na —

Diphenhydramine Antihistamine 62796 58-73-1 0.023 na na D(1)

Salbutamol (albuterol) Anti-inflammatory; bronchodilator62020 18559-94-9 0.014 na na —

Sulfamethoxazole Antibacterial, antiprotozoal 62021 723-46-6 0.024 na na D(1)

Thiabendazole Anthelmintic 62801 148-79-8 0.025 na na —

Trimethoprim Antibacterial 62023 738-70-5 0.020 na na —

Warfarin Anticoagulant 62024 81-81-2 0.002 na na —

1

The median matrix-spike recovery was less than 70 percent. Low recoveries may indicate that the compound might not have been detected in some samples 

if it was present at very low concentrations.

28  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3E. Wastewater-indicator compounds, primary uses or sources, comparative thresholds, and reporting information for the USGS 

National Water Quality Laboratory schedule 1433—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting 

level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant 

level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; RSD5-

US, U.S. Environmental Protection Agency risk-specific dose at a risk factor of 10-5; D, detected; na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

Acetophenone Fragrance, flavor additive 62064 98-86-2 0.5 na na —

Acetyl hexamethyl tetrahydronaphthalene (AHTN) Musk fragrance 62065 21145-77-7 0.5 na na —

Anthracene Wood preservative, combustion product 34221 120-12-7 0.5 na na —

Anthraquinone Dye/textiles, seed treatment 62066 84-65-1 0.5 na na —

Benzo[a]pyrene Combustion product 34248 50-32-8 0.5 MCL-US 0.2 —(3)

Benzophenone Fixative for perfumes and 

soaps 

62067 119-61-9 0.5 na na —

Bisphenol A Polycarbonate resins, flame 

retardant

62069 80-05-7 1 na na —(3)

Bromacil Herbicide 04029 314-40-9 0.5 HAL-US 70 —

Bromoform (tribromomethane) Disinfection by-product 34288 75-25-2 0.5 MCL-US 80 —

3-tert-Butyl-4-hydroxy anisole 

(BHA) 

Antioxidant, general preservative 62059 25013-16-5 5 na na —(3)

Caffeine Beverages 50305 58-08-2 0.5 na na —(4)

Camphor Flavor, odorant, ointments 62070 76-22-2 0.5 na na —

Carbaryl Insecticide 82680 63-25-2 1 RSD5-US 400 —

Carbazole Insecticide 62071 86-74-8 0.5 na na —

Chlorpyrifos Insecticide 38933 2921-88-2 0.5 HAL-US 2 —

Cholesterol Fecal indicator, plant sterol 62072 57-88-5 2 na na —

3-beta-Coprostanol Carnivore fecal indicator 62057 360-68-9 2 na na —(3)

Cotinine Primary nicotine metabolite 62005 486-56-6 1 na na —

para-Cresol Wood preservative 62084 106-44-5 1 na na —

4-Cumylphenol Nonionic detergent metabolite 62060 599-64-4 1 na na —

N,N-diethyl-meta-toluamide 

(DEET) 

Insecticide 62082 134-62-3 0.5 na na —

1,4-Dichlorobenzene Moth repellant, fumigant, 

deodorant 

34572 106-46-7 0.5 MCL-CA 5 —(3)

2,6-Dimethylnaphthalene Diesel/kerosene 62055 581-42-0 0.5 na na —(3)

Diazinon Insecticide 39572 333-41-5 0.5 HAL-US 1 —

4-Nonylphenol diethoxylates Nonionic detergent metabolite 62083 na 5 na na —(2)

4-Octylphenol diethoxylates Nonionic detergent metabolite 61705 na 1 na na —

4-Octylphenol monoethoxylates Nonionic detergent metabolite 61706 na 1 na na —

Fluoranthene Component of coal tar and 

asphalt 

34377 206-44-0 0.5 na na —

Hexahydrohexamethylcyclopentabenzopyran (HHCB) Musk fragrance 62075 1222-05-5 0.5 na na —

Indole Pesticide ingredient 62076 120-72-9 0.5 na na —

Isoborneol Fragrance in perfumery 62077 124-76-5 0.5 na na —

Isophorone Solvent 34409 78-59-1 0.5 HAL-US 100 —

Isopropylbenzene Fuels, paint thinner 62078 98-82-8 0.5 NL-CA 770 —(3)

Isoquinoline Flavors and fragrances 62079 119-65-3 0.5 na na —

d-Limonene Fungicide 62073 5989-27-5 0.5 na na —(3)

Table 3E. Wastewater-indicator compounds, primary uses or sources, comparative thresholds, and reporting information for the USGS 

National Water Quality Laboratory schedule 1433.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting 

level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant 

level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; RSD5-

US, U.S. Environmental Protection Agency risk-specific dose at a risk factor of 10-5; D, detected; na, not available; μg/L, micrograms per liter; —, not detected]

Tables 29
Table 3E. Wastewater-indicator compounds, primary uses or sources, comparative thresholds, and reporting information for the USGS 

National Water Quality Laboratory schedule 1433—Continued.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting 

level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant 

level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; RSD5-

US, U.S. Environmental Protection Agency risk-specific dose at a risk factor of 10-5; D, detected; na, not available; μg/L, micrograms per liter; —, not detected]

Constituent Primary use 

or source

USGS 

parameter 

code

CAS 

number

 LRL 

(μg/L)

Threshold 

type1

Threshold 

value 

(μg/L)

Detection

Menthol Cigarettes, cough drops, liniment62080 89-78-1 0.5 na na —

Metalaxyl Herbicide, fungicide 50359 57837-19-1 0.5 na na —

3-Methyl-1(H)-indole (Skatole) Fragrance, stench in feces 62058 83-34-1 1 na na —

5-Methyl-1H-benzotriazole Antioxidant in antifreeze and 

deicers 

62063 136-85-6 2 na na —(3)

1-Methylnaphthalene Gasoline, diesel fuel, or crude 

oil 

62054 90-12-0 0.5 na na —(3)

2-Methylnaphthalene Gasoline, diesel fuel, or crude 

oil 

62056 91-57-6 0.5 na na —(3)

Methyl salicylate Liniment, UV-absorbing lotion 62081 119-36-8 0.5 na na —

Metolachlor Herbicide 39415 51218-45-2 0.5 HAL-US 700 —

Naphthalene Fumigant, moth repellent, 

gasoline 

34443 91-20-3 0.5 NL-CA 17 —

para-Nonylphenol (total) Nonionic detergent metabolite 62085 84852-15-3 5 na na —

4-n-Octylphenol Nonionic detergent metabolite 62061 1806-26-4 1 na na —(3)

4-tert-Octylphenol Nonionic detergent metabolite 62062 140-66-9 1 na na —

Pentachlorophenol Herbicide, wood preservative 34459 87-86-5 2 MCL-US 1 —(3)

Phenanthrene Explosives, oil, combustion 

product 

34462 85-01-8 0.5 na na —

Phenol Disinfectant, organic synthesis 34466 108-95-2 0.5 HAL-US 2000 —

Prometon Herbicide 04037 1610-18-0 0.5 HAL-US 100 —

Pyrene Component of coal tar and 

asphalt 

34470 129-00-0 0.5 na na —

beta-Sitosterol Plant sterol 62068 83-46-5 2 na na —(3)

beta-Stigmastanol Plant sterol 62086 19466-47-8 2 na na —(3)

Tetrachloroethene (PCE) Solvent, degreaser 34476 127-18-4 0.5 MCL-US 5 D5

Tributyl phosphate Antifoaming agent, flame 

retardant 

62089 126-73-8 0.5 na na —

Triclosan Disinfectant, antimicrobial 62090 3380-34-5 1 na na —

Triethyl citrate (ethyl citrate) Cosmetics, pharmaceuticals 62091 77-93-0 0.5 na na —

Triphenyl phosphate Plasticizer, resin, flame 

retardant

62092 115-86-6 0.5 na na —

Tri(2-butoxyethyl)phosphate Flame retardant 62093 78-51-3 0.5 na na —

Tri(2-chloroethyl)phosphate Plasticizer, flame retardant 62087 115-96-8 0.5 na na —

Tri(dichlorisopropyl)phosphate Flame retardant 62088 13674-87-8 0.5 na na —

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is lower 

than the MCL-US or no MCL-US exists.

2

The median matrix-spike recovery was greater than 130 percent.

3

The median matrix-spike recovery was less than 70 percent. Low recoveries may indicate that the compound might not have been detected in some samples if 

it was present at very low concentrations.

4

The preferred analytical schedule for caffeine is schedule 2080 (table 3D).

5

The preferred analytical schedule for tetrachloroethene (PCE) is schedule 2020 (table 3A).

30 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3F. Constituents of special interest, primary uses or sources, comparative thresholds, and reporting information for the 

Montgomery Watson-Harza Laboratory.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. The laboratory entity code for the Mongomery WatsonHarza Laboratory in the USGS National Water Information System (NWIS) is CA-MWHL. CAS, Chemical Abstract Service; MRL, minimum reporting level; 

NL-CA, California Department of Public Health notification level; D, detected in ground-water samples (table 8); μg/L, micrograms per liter; —, not detected]

Constituent Primary use or source

USGS 

parameter 

code

CAS 

number

 MRL 

(μg/L)

Threshold 

type

Threshold 

value 

(μg/L)

Detection

Perchlorate Rocket fuel, fireworks, 

flares

61209 14797-73-0 0.5 NL-CA 6 D

1,2,3-Trichloropropane (TCP) Industrial solvent 77443 96-18-4 0.005 NL-CA 0.005 D

N-Nitrosodimethylamine 

(NDMA)

Rocket fuel, plasticizer 64176 62-75-9 0.002 NL-CA 0.010 —

Tables 31
Table 3G. Nutrients and dissolved organic carbon, comparative thresholds, and reporting information for the USGS National Water 

Quality Laboratory schedule 2755 and parameter code 2613.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory 

reporting level; HAL-US, U.S. Environmental Protection Agency lifetime health advisory level; MCL-US, U.S. Environmental Protection Agency maximum 

contaminant level; D, detected in ground-water samples (table 9); na, not available; mg/L, milligrams per liter]

Constituent

USGS 

parameter 

code

CAS

 number

 LRL 

(mg/L)

Threshold 

type1

Threshold 

value 

(mg/L)

Detection

Ammonia 00608 7664-41-7 0.010 HAL-US 30 D

Nitrite (as nitrogen) 00613 14797-65-0 0.002 MCL-US 1 D

Nitrate plus nitrite (as nitrogen) 00631 na 0.060 MCL-US 10 D

Total nitrogen (ammonia, nitrite, nitrate, organic 

nitrogen)

62854 17778-88-0 0.06 na na D

Phosphorus, phosphate, orthophosphate (as phosphorus)00671 14265-44-2 0.006 na na D

Dissolved organic carbon (DOC) 00681 na 0.33 na na D

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

32 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3H. Major and minor ions and trace elements, comparative thresholds, and reporting information for the USGS National 

Water Quality Laboratory schedule 1948.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. CAS, Chemical Abstract Service; LRL, laboratory reporting level; AL-US, U.S. Environmental Protection Agency action level; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; MCLCA, California Department of Public Health maximum contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; 

NL-CA, California Department of Public Health notification level; SMCL-CA, California Department of Public Health secondary maximum contaminant 

level; D, detected in ground-water samples (tables 10 and 11); na, not available; mg/L, milligrams per liter; μg/L, micrograms per liter; —, not detected]

Constituent

USGS

 parameter 

code

CAS

 number LRL Threshold type1

Threshold 

value Detection

Major and minor ions (mg/L)

Bromide 71870 24959-67-9 0.02 na na D

Calcium 00915 7440-70-2 0.02 na na D

Chloride 00940 16887-00-6 0.2 SMCL-CA 2

250 (500) D

Fluoride 00950 16984-48-8 0.10 MCL-CA 2 D

Iodide 78165 7553-56-2 0.002 na na D

Magnesium 00925 7439-95-4 0.008 na na D

Potassium 00935 7440-09-7 0.16 na na D

Silica 00955 7631-86-9 0.04 na na D

Sodium 00930 7440-23-5 0.20 na na D

Sulfate 00945 14808-79-8 0.18 SMCL-CA 250 (500) D

Residue on evaporation (total dissolved 

solids, TDS)

70300 na 10 SMCL-US 2

500 (1,000) D

Trace elements (μg/L)

Aluminum 01106 7429-90-5 1.6 MCL-CA 1,000 D

Antimony 01095 7440-36-0 0.2 MCL-US 6 D

Arsenic 01000 7440-38-2 0.12 MCL-US 10 D

Barium 01005 7440-39-3 0.2 MCL-CA 1,000 D

Beryllium 01010 7440-41-7 0.06 MCL-US 4 D

Boron 01020 7440-42-8 8 NL-CA 1,000 D

Cadmium 01025 7440-43-9 0.04 MCL-US 5 D

Chromium 01030 7440-47-3 0.04 MCL-CA 50 D

Cobalt 01035 7440-48-4 0.04 na na D

Copper 01040 7440-50-8 0.4 AL-US 1,300 D

Iron 01046 7439-89-6 6 SMCL-CA 300 D

Lead 01049 7439-92-1 0.08 AL-US 15 D

Lithium 01130 7439-93-2 0.6 na na D

Manganese 01056 7439-96-5 0.2 SMCL-CA 50 D

Mercury 71890 7439-97-6 0.010 MCL-US 2 —

Molybdenum 01060 7439-98-7 0.4 HAL-US 40 D

Nickel 01065 7440-02-0 0.06 MCL-CA 100 D

Selenium 01145 7782-49-2 0.08 MCL-US 50 D

Silver 01075 7440-22-4 0.20 SMCL-CA 100 D

Strontium 01080 7440-24-6 0.4 HAL-US 4,000 D

Thallium 01057 7440-28-0 0.04 MCL-US 2 D

Tungsten 01155 7440-33-7 0.06 na na D

Uranium 22703 7440-61-1 0.04 MCL-US 30 D

Vanadium 01085 7440-62-2 0.10 NL-CA 50 D

Zinc 01090 7440-66-6 0.6 HAL-US 2,000 D

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

2

The recommended SMCL-CA thresholds for chloride, sulfate, and TDS are listed with the upper SMCL-CA thresholds in parentheses.

Tables 33
Table 3I. Arsenic, chromium, and iron species, comparative thresholds, and reporting information for the USGS Trace Metal 

Laboratory, Boulder, Colorado.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. The laboratory entity code for the USGS Trace Metal 

Laboratory in the USGS National Water Information System (NWIS) is USGSTMCO. CAS, Chemical Abstract Service; MD, method detection level; 

HAL-US, U.S. Environmental Protection Agency lifetime health advisory; MCL-CA, California Department of Public Health maximum contaminant level; 

MCL-US, U.S. Environmental Protection Agency maximum contaminant level; na, not available; mg/L, micrograms per liter; D, detected in ground-water 

samples (table 12)]

Constituent 

(valence state)

USGS 

parameter 

code

CAS 

number

MD 

(μg/L)

Threshold 

type1

Threshold 

level 

(μg/L)

Detection

Arsenic (III) 99034 22569-72-8 1 na na D

Arsenic (total) 01000 7440-38-2 0.5 MCL-US 10 D

Chromium (VI), hexavalent 01032 18540-29-9 1 na na D

Chromium (total) 01030 7440-47-3 1 MCL-CA 50 D

Iron (II) 01047 7439-89-6 2 na na D

Iron (total) 01046 7439-89-6 2 HAL-US 300 D

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

34 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3J. Isotopic and radioactive constituents, comparative thresholds, and reporting information for laboratories.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. Laboratory entity codes are listed in the footnotes. Stable 

isotope ratios are reported in the standard delta notation (d), the ratio of a heavier isotope to more common lighter isotope of that element, relative to a standard reference material. CAS, Chemical Abstract Service; CSU, combined standard uncertainty; CV, critical value; MCL-CA, California Department of Public 

Health maximum contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; MRL, minimum reporting level; MU, 

method uncertainty; na, not available; pCi/L, picocuries per liter; SSMDC, sample specific minimum detectable concentration; D, detected in ground-water 

samples (tables 13 and 14)]

Constituent

USGS 

parameter 

code

CAS 

number

Reporting 

level 

type

Reporting 

level or 

uncertainty

Threshold 

type1

Threshold 

value

Detection

Stable isotope ratios (per mil)

δ2

H of water2 82082 na MU 2 na na D

δ18O of water2 82085 na MU 0.20 na na D

δ13C of dissolved carbonates3 82081 na 1 sigma 0.05 na na D

Radioactive constituents (percent modern)

Carbon-144 49933 14762-75-5 1 sigma 0.002 na na D

Radioactive constituents (pCi/L)

Radon-2225 82303 14859-67-7 SSMDC CSU and CV Prop. MCL-US 6

300 (4,000) D

Tritium7 07000 10028-17-8 MRL 1 MCL-CA 20,000 D

Gross-alpha radioactivity, 72-hour and 

30-day counts8

62636, 62639 12587-46-1 SSMDC CSU and CV MCL-US 15 D

Gross-beta radioactivity, 72-hour and 30-

day counts8

62642, 62645 12587-47-2 SSMDC CSU and CV MCL-CA 50 D

Radium-2268 09511 13982-63-3 SSMDC CSU and CV MCL-US 9

5 D

Radium-2288 81366 15262-20-1 SSMDC CSU and CV MCL-US 95 D

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

2

USGS Stable Isotope Laboratory, Reston, Virginia (USGSSIVA).

3

University of Waterloo (contract laboratory) (CAN-UWIL).

4

University of Arizona, Accelerator Mass Spectrometry Laboratory (contract laboratory) (AZ-UAMSL).

5

USGS National Water Quality Laboratory (USGSNWQL).

6

Two MCLs have been proposed for Radon-222. The proposed Alternaltive MCL is in parentheses.

7

USGS Stable Isotope and Tritium Laboratory, Menlo Park, California (USGSH3CA).

8

Eberline Analytical Services (contract laboratory) (CA-EBERL).

9

The MCL-US threshold for radium is the sum of radium-226 and radium-228.

Tables 35
Table 3K. Noble gases and tritium, comparison thresholds, and reporting information for the Lawrence Livermore National 

Laboratory.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property.The laboratory entity code for the Lawrence Livermore 

National Laboratory in the USGS National Water Information System (NWIS) is CA-LLNL. CAS, Chemical Abstract Service; MU, method uncertainty; 

MCL-CA, California Department of Public Health maximum contaminant level; na, not available; cm3 STP/g, cubic centimeters of gas at standard temperature and pressure per gram of water; pCi/L, picocuries per liter; D, detected in ground-water samples]

Constituent

USGS 

parameter 

code

CAS 

number

MU 

(percent)

Reporting 

units

Threshold 

type1

Threshold 

 value 

(pCi/L)

Detection

Helium-3/Helium-4 61040 na/7440-59-7 0.75 atom ratio na na D

Argon 85563 7440-37-1 2 cm3

 STP/g na na D

Helium-4 85561 7440-59-7 2 cm3

 STP/g na na D

Krypton 85565 7439-90-9 2 cm3

 STP/g na na D

Neon 61046 7440-01-09 2 cm3

 STP/g na na D

Xenon 85567 7440-63-3 2 cm3

 STP/g na na D

Tritium 07000 10028-17-8 1 pCi/L MCL-CA 20,000 D

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

36 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 3L. Microbial constituents, comparison thresholds, and reporting information for the USGS Ohio Microbiology Laboratory 

parameter codes 90901, 90900, 99335, and 99332.

[The five-digit USGS parameter code is used to uniquely identify a specific constituent or property. MDL, method detection limit; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; TT-US, U.S. Environmental Protection Agency treatment technique - a required process intended to 

reduce the level of contamination in drinking water; na, not available; mL, milliliters; D, detected in ground-water samples (table 15); —, not detected]

Constituent

USGS 

parameter 

code

Primary 

source

 MDL Threshold 

type1

Threshold 

value Detection

Escherichia coli 2 90901 Sewage and animal waste 

indicator

1 colony/

100 mL

TT-US Zero —

Total coliform—including fecal 

coliform and E. coli)2

90900 Sewage and animal waste 

indicator

1 colony/

100 mL

MCL-US 5 percent of samples 

positive per month

D

F-specific coliphage3 99335 Sewage and animal waste 

indicator

na TT-US 99.99 percent killed/

inactivated

—

Somatic coliphage3 99332 Sewage and animal waste 

indicator

na TT-US 99.99 percent killed/

inactivated

—

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

2

Analyzed in the field.

3

Analyzed by the USGS Ohio Microbiology Laboratory (laboratory entity code USGSOHML).

Tables 37
Table 4. Water-quality indicators in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study, California, June 2006—Continued. 

[The five-digit number below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property; 

SMCL-CA, California Department of Public Health secondary maximum contaminant level; SMCL-US, U.S. Environmental Protection Agency secondary 

maximum contaminant level; SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; C, celsius; E, estimated value; 

mg/L, milligrams per liter; mm, millimeter; nc, sample not collected; na, not available; NTU, nephelometric turbidity unit; μS/cm, microsiemens per centimeter; 

CaCO3, calcium carbonate]

GAMA 

identification 

No.

Turbidity, 

field 

(NTU) 

(63676)

Dissolved 

oxygen, 

field 

(mg/L) 

(00300) 

Water 

temperature, 

field 

(degrees C) 

 (00010)

pH, lab 

(standard 

units) 

(00403)

pH, field 

(standard 

units) 

(00400)

Specific 

conductance, 

lab 

(μS/cm 

at 25°C) 

(90095)

Specific 

conductance, 

field 

(μS/cm 

at 25°C) 

(00095)

Alkalinity, 

lab (mg/L 

as CaCO3

) 

(29801)

Alkalinity, 

field (mg/L 

as CaCO3

) 

(29802)

Threshold type na na na SMCL-US SMCL-US SMCL-CA1 SMCL-CA1 na na

Threshold level na na na 6.5 - 8.5 6.5 - 8.5 900 (1,600) 900 (1,600) na na

Grid wells

SOSA-01 nc 1.4 15.7 nc nc nc 85 nc nc

SOSA-02 nc 4.3 15.8 nc nc nc nc nc nc

SOSA-03 0.3 11.6 20.1 7.3 6.9 661 656 248 239

SOSA-04 nc 2.2 22.8 nc nc nc nc nc nc

SOSA-05 nc 4.7 19.4 nc nc nc 337 nc nc

SOSA-06 nc 0.1 19.2 nc nc nc 301 nc nc

SOSA-07 0.5 0.1 15.4 7.5 6.5 127 135 60 55

SOSA-08 nc 0.6 19.9 nc nc nc 649 nc nc

SOSA-09 nc 0.6 14.8 nc nc nc * 1,020 nc nc

SOSA-10 0.4 0.8 16.7 6.6 * 6.0 365 367 144 140

SOSA-11 nc 10.5 18.1 nc nc nc 501 nc nc

SOSA-12 nc 2.1 14.6 nc nc nc 86 nc nc

SOSA-13 0.2 7.0 17.5 7.8 7.6 490 485 186 180

SOSA-14 nc 6.0 21.5 nc nc nc 168 nc nc

SOSA-15 nc 7.8 8.1 6.8 nc 242 241 121 nc

SOSA-16 nc 7.0 20.0 nc nc nc 422 nc nc

SOSA-17 nc 1.2 19.5 nc nc nc 315 nc nc

SOSA-18 nc 5.4 20.0 nc nc nc 856 nc nc

SOSA-19 nc 1.4 20.5 nc nc nc 352 nc nc

SOSA-20 nc 5.1 18.5 nc nc nc 337 nc nc

SOSA-21 nc 1.2 21.0 nc nc nc 570 nc nc

SOSA-22 nc 6.6 6.5 6.1 nc 39 37 17 nc

SOSA-23 nc E 8.0 17.5 nc nc nc 549 nc nc

SOSA-24 nc 0.2 22.5 nc nc nc 457 nc nc

SOSA-25 nc 4.2 15.5 nc nc nc 457 nc nc

Table 4. Water-quality indicators in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study, California, June 2006.

[The five-digit number below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property; 

SMCL-CA, California Department of Public Health secondary maximum contaminant level; SMCL-US, U.S. Environmental Protection Agency secondary maximum contaminant level; SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; C, celsius; E, estimated value; mg/L, 

milligrams per liter; mm, millimeter; nc, sample not collected; na, not available; NTU, nephelometric turbidity unit; μS/cm, microsiemens per centimeter; CaCO3, 

calcium carbonate]

38  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 4. Water-quality indicators in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study, California, June 2006—Continued. 

[The five-digit number below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property; 

SMCL-CA, California Department of Public Health secondary maximum contaminant level; SMCL-US, U.S. Environmental Protection Agency secondary 

maximum contaminant level; SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; C, celsius; E, estimated value; 

mg/L, milligrams per liter; mm, millimeter; nc, sample not collected; na, not available; NTU, nephelometric turbidity unit; μS/cm, microsiemens per centimeter; 

CaCO3, calcium carbonate]

GAMA 

identification 

No.

Turbidity, 

field 

(NTU) 

(63676)

Dissolved 

oxygen, 

field 

(mg/L) 

(00300) 

Water 

temperature, 

field 

(degrees C) 

 (00010)

pH, lab 

(standard 

units) 

(00403)

pH, field 

(standard 

units) 

(00400)

Specific 

conductance, 

lab 

(μS/cm 

at 25°C) 

(90095)

Specific 

conductance, 

field 

(μS/cm 

at 25°C) 

(00095)

Alkalinity, 

lab (mg/L 

as CaCO3

) 

(29801)

Alkalinity, 

field (mg/L 

as CaCO3

) 

(29802)

Threshold type na na na SMCL-US SMCL-US SMCL-CA1 SMCL-CA1 na na

Threshold level na na na 6.5 - 8.5 6.5 - 8.5 900 (1,600) 900 (1,600) na na

SOSA-26 nc 2.1 15.3 nc nc nc 469 nc nc

SOSA-27 nc E 2 17.0 nc nc nc 404 nc nc

SOSA-28 nc 6.3 16.5 nc nc nc 897 nc nc

SOSA-29 nc 1.4 18.0 nc nc nc 377 nc nc

SOSA-30 nc 6.6 21.3 nc nc nc 507 nc nc

SOSA-31 nc 7.8 16.7 nc nc nc 836 nc nc

SOSA-32 nc 8.4 17.8 nc 7.4 nc 474 nc nc

SOSA-33 nc < 0.1 18.0 nc 7.2 nc 469 nc nc

SOSA-34 nc 11.6 16.6 nc 7.2 nc 731 nc nc

SOSA-35 nc 0.2 19.8 * 8.7 * 8.6 * 1,730 * 1,730 710 nc

Flow-path wells

SOSAFP-01 nc 5.2 18.7 7.8 nc 508 479 150 nc

SOSAFP-02 2.2 < 0.1 18.9 6.7 * 6.2 518 513 254 256

SOSAFP-03 nc 3.8 19.9 8.1 nc 386 391 138 nc

SOSAFP-04 0.4 8.3 18.5 7.9 nc 527 543 182 nc

SOSAFP-05 0.2 3.5 18.5 7.9 7.7 419 419 155 150

SOSAFP-06 0.2 7.9 18.5 7.8 7.7 476 477 172 167

SOSAFP-07 nc 8.5 17.0 7.6 nc 850 862 235 nc

SOSAFP-08 nc 3.1 18.3 7.4 nc 683 686 197 nc

SOSAFP-09 nc 12.3 17.3 7.6 7.0 679 676 214 nc

SOSAFP-10 nc 4.0 17.6 7.4 nc 523 526 161 nc

SOSAFP-11 nc 5.2 17.1 7.7 nc 460 377 179 nc

SOSAFP-12 nc 3.3 18.8 7.5 7.3 543 537 150 nc

SOSAFP-13 nc 7.0 18.7 7.8 nc 439 348 159 nc

SOSAFP-14 nc 9.7 17.7 7.7 nc 532 517 187 nc

SOSAFP-15 nc 9.4 16.6 7.7 nc 577 522 197 nc

*

Value above threshold level.

1

The SMCL-CA for specific conductance has recommended and upper threshold values. The upper value is shown in parentheses.

Tables 39
Table 5. Volatile organic compounds (VOCs), and gasoline oxygenates and degradates detected in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent 

or property. Samples from all fifty wells were analyzed, but only samples with detections are listed. Analytes are listed in order of decreasing detection frequency 

in the thirty-five grid wells. All analytes are listed in tables 3A and 3B. SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flowpath well; LRL, laboratory reporting level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; MCL-CA; California Department of 

Public Health maximum contaminant level; E, estimated value; V, analyte detected in sample and an associated blank thus data are not included in ground-water 

quality assessment; μg/L, microgram per liter; —, not detected]

GAMA 

well 

identification 

number

Chloroform 

(trichloromethane) 

(μg/L) 

(32106)

Tetrachloroethene 

(PCE) 

(μg/L) 

(34475)

Carbon 

tetrachloride 

(tetrachloromethane) 

(μg/L) 

(32102)

Methyl 

tert-butyl ether 

(MTBE) 

(μg/L) 

(78032)

Trichloroethene 

(TCE) 

(μg/L) 

(39180)

Trichlorofluoromethane 

(CFC-11) 

(μg/L) 

(34488)

1,1,2-Trichloro1,2,2-trifluoroethane 

(CFC-113) 

(μg/L) 

(77652)

1,2-Dichlorobenzene 

(μg/L) 

(34536)

cis-1,2-

Dichloroethene 

(μg/L) 

(77093)

1,2-Dichloropropane 

(μg/L) 

(34541)

Toluene 

(μg/L) 

(34010)

VOC 

detections 

per well

LRL 0.024 0.030 0.06 0.10 0.04 0.08 0.038 0.048 0.024 0.029 0.02

Threshold type1 MCL-US MCL-US MCL-CA MCL-CA MCL-US MCL-CA MCL-CA MCL-US MCL-CA MCL-CA MCL-CA

Threshold level 2

80 5 0.5 13 5 150 1200 600 6 5 150

Grid wells

SOSA-02 — — — — — — E0.05 — — — — 1

SOSA-03 0.13 E0.02 — — — — — — — — — 2

SOSA-04 — — — — — 0.1 — — — — — 1

SOSA-09 0.13 — — — — — — — — — — 1

SOSA-13 — — — — — — — — — — V0.02 0

SOSA-14 0.14 — — — — — — — — — — 1

SOSA-16 0.11 0.35 E0.23 — — — — — — — — 3

SOSA-17 E0.06 — — — — — — — — — — 1

SOSA-21 — E0.05 — E0.1 E0.02 — — — — — — 3

SOSA-22 — — — — — — — — — — V0.02 0

SOSA-25 — E0.04 — — — — — — — — — 1

SOSA-29 E0.02 — — — — — — — — — — 1

SOSA-34 — E0.04 — — — — — — — — — 1

Number of 

detections

6 5 1 1 1 1 1 0 0 0 16

Detection 

frequency 

(percent)

17 14 3 3 3 3 3 3

31

Flow-path wells

SOSAFP-01 — E0.02 — — — — — — — — — 1

SOSAFP-04 E0.02 3.44 — — — — — E0.01 E0.03 — — 4

SOSAFP-05 — 0.24 — — — — — — — — — 1

SOSAFP-07 — 0.16 — — — E0.05 — — — — — 2

SOSAFP-08 — E0.09 — — — — — — — — — 1

SOSAFP-09 — — — — — — — — — 0.18 — 1

SOSAFP-15 — E0.04 — — — — — — — — 1

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is lower 

than the MCL-US or no MCL-US exists.

2

The MCL-US threshold for trihalomethanes is the sum of chloroform, bromoform, bromodichloromethane, and dibromochloromethane.

3

Frequency of detection of at least one VOC in the grid wells. Detections with V remark codes are not included.

40 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 6. Pesticides and pesticide degradates detected in samples collected for the Southern Sierra Groundwater 

Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a 

specific constituent or property. Samples from all fifty wells were analyzed, but only samples with detections are listed. Analytes are listed 

in order of decreasing detection frequency in the thirty-five grid wells. All analytes are listed in table 3C. SOSA, Southern Sierra study unit 

grid well; SOSAFP, Southern Sierra study unit flow-path well; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; 

MCL-US, U.S. Environmental Protection Agency maximum contaminant level; MCL-CA; California Department of Public Health maximum 

contaminant level; E, estimated value; LRL, laboratory reporting level; na, not available; μg/L, microgram per liter; —, not detected.]

GAMA well 

identification

 number

Atrazine 

(μg/L) 

 (39632)

Deethylatrazine 

(μg/L) 

(04040)

Simazine 

 (μg/L) 

(04035)

Prometon 

(μg/L) 

(04037)

Fipronil 

sulfide 

(μg/L) 

(62167)

Pesticide 

detections 

per well

LRL 0.007 0.014 0.005 0.01 0.013

Threshold type1 MCL-CA na MCL-US HAL-US na

Threshold level 1 na 4 100 na

Grid Wells

SOSA-03 E0.005 E0.005 — — — 2

SOSA-07 — — — — E0.005 1

SOSA-08 — — — E0.01 — 1

SOSA-11 E0.006 E0.01 0.008 — — 3

SOSA-14 E0.005 E0.011 E0.005 — — 3

SOSA-16 0.008 E0.015 E0.007 E0.01 — 4

SOSA-31 — — E0.003 — — 1

SOSA-34 E0.005 E0.013 — — — 2

Number of detections 5 5 4 2 1 17

Detection frequency (percent) 14 14 11 6 3 2

23

Flow-path wells

SOSAFP-04 E0.008 E0.012 — — — 2

SOSAFP-07 E0.004 E0.005 — — — 2

SOSAFP-08 — E0.005 — — — 1

SOSAFP-09 E0.007 E0.007 E0.003 — — 3

SOSAFP-15 E0.004 E0.006 E0.006 — — 3

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the 

MCL-CA is lower than the MCL-US or no MCL-US exists.

2

Frequency of detection of at least one pesticide or pesticide degradate in the grid wells.

Tables 41
Table 7. Pharmaceutical compounds detected in samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to 

uniquely identify a specific constituent or property. Samples from all fifty wells were analyzed, but only samples with 

detections are listed. Analytes are listed in order of decreasing detection frequency in the thirty-five grid wells. All analytes 

are listed in table 3D. SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; E, 

estimated value; LRL, laboratory reporting level; na, not available; V, analyte detected in sample and an associated blank 

thus data are not included in ground-water quality assessment; μg/L, microgram per liter; —, not detected]

GAMA well 

identification 

number

Carbamazapine 

(μg/L) 

(62793)

Sulfamethoxazole 

(μg/L) 

(62021)

Diphenhydramine 

(μg/L) 

(62796)

Pharma 

ceutical 

detections 

per well

LRL 0.018 0.024 0.023

Threshold type na na na

Threshold level na na na

Grid wells

SOSA-10 — — V0.004 0

SOSA-16 — 0.103 — 1

SOSA-21 E0.009 — — 1

SOSA-23 — — V0.005 0

Number of detections 1 1 0 2

Detection frequency (percent) 3 3 1

6

Flow-path wells

SOSAFP-04 E0.004 — — 1

1

Frequency of detection of at least one pharmaceutical compound in the grid wells.

42 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 8. Constituents of special interest [Perchlorate, N-Nitrosodimethylamine (NDMA), and 1,2,3-

Trichloropropane (1,2,3-TCP)] detected in samples collected in the Southern Sierra Groundwater 

Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used 

to uniquely identify a specific constituent or property. Analyses done by the Mongomery Watson-Harza laboratory 

(laboratory entity code CA-MWHL). Information about analytes given in table 3F. Samples from all fifty wells were 

analyzed for perchlorate, samples from the twenty-two intermediate and slow wells were sampled for NDMA and 

1,2,3-TCP; only wells with at least one detection are listed. SOSA, Southern Sierra study unit grid well; SOSAFP, 

Southern Sierra study unit flow-path well; MRL, method reporting level; NL-CA, California Department of Public 

Health notification level; μg/L, microgram per liter; na, not analyzed; —, analyzed but not detected]

GAMA well 

identification 

number

Perchlorate 

(μg/L) 

(61209)

N-Nitrosodimethylamine (NDMA) 

(μg/L) 

(64176)

1,2,3-Trichloropropane 

(μg/L) 

(77443)

Threshold type NL-CA NL-CA NL-CA

Threshold level 6 0.01 0.005

MRL 0.5 0.002 0.005

Grid wells1

SOSA-30 0.96 na na

SOSA-31 .51 na na

SOSA-32 .79 na na

SOSA-34 1.7 na na

Number of wells with detections 4

Detection frequency (percent) 11

Flow-path wells

SOSAFP-01 1.1 — —

SOSAFP-10 .92 — —

SOSAFP-11 1.1 — *.02

SOSAFP-12 .8 — —

SOSAFP-14 .69 — —

SOSAFP-15 1.0 — —

*

Value above threshold level.

1

SOSA-35 was analyzed with an MRL of 5 μg/L for perchlorate.

Tables 43
Table 9. Nutrients and dissolved organic carbon detected in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Samples from the twenty-two slow and intermediate wells were analyzed. Information about analytes given in table 3G. SOSA, Southern 

Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; HAL-US, U.S. Environmental Protection Agency Lifetime Health Advisory; 

MCL-US, U.S. Environmental Protection Agency maximum contaminant level; E, estimated value; LRL, laboratory reporting level; mg/L, milligram per liter; 

na, not available; V, analyte detected in sample and an associated blank thus data are not included in ground-water quality assessment; —, not detected]

GAMA well 

identification 

number

Ammonia, 

as nitrogen 

(mg/L) 

(00608)

Nitrite plus 

nitrate, 

as nitrogen 

(mg/L) 

(00631)

 Nitrite, 

as nitrogen 

(mg/L) 

(00613)

Total nitrogen 

(nitrate + nitrite + 

ammonia + 

organic-nitrogen) 

as nitrogen 

(mg/L) 

(62854)

Phosphorous, 

as orthophos 

phate 

 (mg/L) 

(00671)

Dissolved 

organic 

carbon 

(DOC) 

(mg/L) 

(00681)

Threshold type1 HAL-US MCL-US MCL-US na na na

Threshold level 30 10 1 na na na

LRL 0.01 0.06 0.002 0.06 0.006 0.33

Grid wells

SOSA-03 — 5.10 — 2

4.88 0.055 0.4

SOSA-07 0.040 0.07 E0.002 0.15 0.062 1.4

SOSA-10 0.013 0.93 E0.001 0.96 0.054 0.7

SOSA-13 E0.006 6.28 — 6.53 0.029 V0.3

SOSA-15 E0.006 0.10 — 0.11 0.025 0.4

SOSA-22 — 0.47 — 0.49 0.068 0.8

SOSA-35 0.112 0.06 — 0.11 0.129 na

Flow-path wells

SOSAFP-01 E0.006 9.02 — 2

8.50 0.040 V0.2

SOSAFP-02 0.081 — — 0.09 0.014 0.7

SOSAFP-03 — 4.08 — 2

3.91 0.026 V0.2

SOSAFP-04 — 5.48 — 2

5.38 0.031 0.4

SOSAFP-05 E0.007 1.75 — 1.89 0.021 V0.2

SOSAFP-06 — 7.21 — 7.93 0.038 V0.3

SOSAFP-07 — 5.66 — 5.85 0.112 V0.3

SOSAFP-08 E0.006 3.86 — 4.01 0.080 0.4

SOSAFP-09 E0.006 8.08 — 9.03 0.078 0.6

SOSAFP-10 E0.009 3.31 — 3.42 0.093 V0.3

SOSAFP-11 E0.008 2.20 E0.001 2.27 0.058 0.5

SOSAFP-12 E0.007 3.38 E0.002 3.48 0.055 V0.3

SOSAFP-13 E0.007 4.27 E0.002 4.34 0.039 V0.3

SOSAFP-14 — 5.44 — 2

5.31 0.035 0.4

SOSAFP-15 E0.006 6.17 — 6.29 0.066 0.5

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

2

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 criteria of a 10 percent relative percent difference.

44 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 10. Major and minor ions and dissolved solids detected in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006.

[The five digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent 

or property. Samples from the twenty-two slow and intermediate wells were analyzed. Information about analytes given in table 3H. SOSA, Southern Sierra 

study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; MCL-CA, California Department of Public Health maximum contaminant level; 

SMCL-CA, California Department of Health Services secondary maximum contaminant level; LRL, laboratory reporting level; mg/L, milligrams per liter; 

E, estimated value; na, not available; —, not detected]

GAMA well 

identification 

 number

Calcium 

(mg/L) 

(00915) 

Magnesium 

(mg/L) 

(00925) 

Potassium 

(mg/L) 

(00935) 

Sodium 

(mg/L) 

(00930) 

Bicarbonate2

(mg/L)

Carbonate2

(mg/L)

Bromide 

(mg/L) 

(71870) 

Chloride 

(mg/L) 

(00940) 

Fluoride 

(mg/L) 

(00950) 

Iodide 

(mg/L) 

(71865)

Silica 

(mg/L) 

 (00955) 

Sulfate 

(mg/L) 

(00945) 

Total 

dissolved 

solids 

(TDS) 

(mg/L) 

(70300)

Threshold 

type1 na na na na na na na

SMCLCA3

MCLCA na naSMCLCA3SMCLCA3

Threshold 

level na na na na na na na

250 

(500) 2 na na

250 

(500)

500 

(1,000)

LRL 0.02 0.008 0.16 0.2 1 1 0.02 0.2 0.1 0.002 0.04 0.18 10

Grid wells

SOSA-03 65.2 19.8 4.64 40.6 302 — 0.07 25.6 0.5 0.004 50.5 47.6 425

SOSA-07 13.6 2.12 1.42 9.32 73 — E0.01 2.24 0.3 0.004 19.4 3.8 86

SOSA-10 32.7 8.16 2.83 30.7 176 — 0.05 13.5 1.8 0.017 37.7 20.4 241

SOSA-13 62.3 9.03 1.02 25.3 225 — 0.07 13.2 0.1 — 22.8 27.4 300

SOSA-15 37.2 4.06 1.36 6.89 147 — — 2.05 E0.1 — 33.3 5.3 163

SOSA-22 3.07 0.307 0.80 3.59 21 — — 0.77 — — 20.8 0.6 47

SOSA-35 1.84 1.52 4.03 411 825 20 0.25 42.3 0.6 0.011 27.8 171 **1,130

Flow-path wells

SOSAFP-01 59.5 7.48 0.92 28.6 181 — 0.14 22.7 0.2 — 22.7 41.0 315

SOSAFP-02 56.7 11.1 5.94 31.9 309 — 0.03 11.3 0.4 0.03 36.4 8.5 329

SOSAFP-03 34.6 4.02 1.19 39.3 166 — 0.07 11.2 0.4 — 18.8 28.5 242

SOSAFP-04 61 10.5 1.45 31.0 220 — 0.10 25.0 0.2 — 22.5 41.4 340

SOSAFP-05 42.5 6.95 1.36 35.4 187 — 0.09 14.7 0.4 — 22.7 33.8 266

SOSAFP-06 62.9 8.34 1.00 25.9 208 — 0.10 14.2 0.1 — 23.2 28.8 302

SOSAFP-07 103 26.9 3.08 37.6 285 — 0.20 63.3 0.4 — 35.7 105 *

558

SOSAFP-08 80.2 16.7 3.93 31.1 240 — 0.13 37.4 0.4 E0.002 41.2 86.4 456

SOSAFP-09 70.5 20.5 2.51 37.5 261 — 0.15 32.4 0.4 E0.001 25.8 61.0 426

SOSAFP-10 56.3 15.2 3.40 24.1 196 — 0.10 17.7 0.3 — 46.7 66.6 354

SOSAFP-11 42.3 12.3 2.61 38.0 217 — 0.16 24.2 0.4 E0.001 25.4 20.4 267

SOSAFP-12 66.3 13.1 4.37 27.4 183 — 0.12 19.0 0.5 — 42.3 85.1 371

SOSAFP-13 49.7 6.96 0.64 34.9 193 — 0.09 13.4 0.9 — 24.4 31.2 280

SOSAFP-14 66.5 9.06 0.78 33.1 227 — 0.11 17.2 0.4 — 23.9 45.4 341

SOSAFP-15 77.8 12.3 1.11 24.5 239 — 0.11 28.4 0.2 E0.001 24.2 39.4 361

*

Value above recommended threshold level.

**Value above upper threshold level.

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is lower 

than the MCL-US or no MCL-US exists.

2

Bicarbonate and carbonate concentrations were calculated from the laboratory alkalinity and pH values (table 4) using the advanced speciation method 

(http://or.water.usgs.gov/alk/methods.html) with pK1 = 6.35, pK2 = 10.33, and pKW = 14.

3

The SMCL-CA for chloride, sulfate, and total dissolved solids have recommended and upper threshold values. The upper value is shown in parentheses.

Tables 45
Table 11. Trace elements detected in ground-water samples collected for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, July to September 2006. 

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Samples from the twenty-two slow and intermediate wells were analyzed. All analytes are listed in table 3H. SOSA, Southern Sierra study unit 

grid-well; SOSAFP, Southern Sierra study unit flow-path well; AL-US, U.S. Environmental Protection Agency action level; HAL-US, U.S. Environmental 

Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant level; MCL-US, U.S. Environmental 

Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; SMCL-CA, California Department of 

Public Health secondary maximum contaminant level; E, estimated value; LRL, laboratory reporting level; na, not available; V, analyte detected in sample and 

an associated blank thus data are not included in ground-water quality analyses; μg/L, microgram per liter; —, not detected]

GAMA well 

identification 

number

Aluminum 

 (μg/L)

 (01106) 

Antimony 

 (μg/L) 

(01095) 

Arsenic 

(μg/L) 

(01000) 

Barium 

(μg/L) 

(01005) 

Beryllium 

(μg/L) 

(01010)

Boron 

(μg/L) 

(01020) 

Cadmium 

(μg/L) 

(01025) 

Chromium 

(μg/L) 

(01030) 

Cobalt 

(μg/L) 

(01035) 

Copper 

(μg/L) 

(01040) 

Iron 

(μg/L) 

(01046) 

Lead 

(μg/L) 

(01049) 

Threshold 

type1 MCL-CA MCL-US MCL-US MCL-CA MCL-US NL-CA MCL-US MCL-CA na AL-US SMCLCA AL-US

Threshold 

level 1,000 6 10 1,000 4 1,000 5 50 na 1,300 300 15

LRL 1.6 0.20 0.12 0.2 0.06 8 0.04 0.040 0.040 0.4 6 0.08

Grid wells

SOSA-03 E1 E0.12 *10.7 55 — 511 — 1.3 0.172 2.2 11 1.19

SOSA-07 — — *23.7 16 — 54 — 0.04 0.133 — *934 0.22

SOSA-10 2.0 — 0.42 21 — 359 0.05 0.05 0.523 E0.3 239 1.03

SOSA-13 — — 0.81 78 — 15 — 5.0 0.096 2.3 — 0.88

SOSA-15 — — E0.10 38 — E8 E0.02 0.08 0.058 V0.8 — 4.07

SOSA-22 23 — — 3 E0.05 E5 — — — 1.2 E3 0.08

SOSA-35 E1.0 — *13.7 2 — *1,280 E0.02 0.06 E0.029 1.7 229 0.35

Flow-path wells

SOSAFP-01 — — 0.92 74 — 51 — 5.8 0.153 V0.8 — 0.33

SOSAFP-02 — — *13.2 56 — 226 E0.04 0.05 0.447 E0.4 *4,200 0.43

SOSAFP-03 E0.9 — 1.90 33 — 74 — 3.2 0.087 V0.5 — E0.04

SOSAFP-04 E1.0 — 1.20 99 — 30 — 2.7 0.142 1.2 — 0.52

SOSAFP-05 E1.0 — 1.30 78 — 42 — 1.4 0.062 1.9 — 1.69

SOSAFP-06 — — 0.86 73 — 16 — 5.5 0.109 1.2 — 0.71

SOSAFP-07 — 0.25 0.95 76 — 68 0.29 2.6 0.24 1.3 — 0.29

SOSAFP-08 E0.9 — 0.82 74 — 57 0.05 3.3 0.186 2.2 — 0.25

SOSAFP-09 — — 0.51 201 — 20 0.06 2.4 0.207 4.9 — 0.75

SOSAFP-10 — — 1.10 49 — 23 0.07 8.4 0.14 V0.9 — 0.20

SOSAFP-11 — — 0.68 108 — 28 E0.03 1.4 0.106 V0.9 E3 0.18

SOSAFP-12 — — 0.89 44 — 64 E0.02 3.3 0.161 1.8 — 0.78

SOSAFP-13 — — 0.59 77 — 116 E0.02 0.86 0.126 V0.9 14 0.75

SOSAFP-14 — — 0.63 109 — 40 E0.02 2.1 0.144 1.4 9 2.03

SOSAFP-15 E1.0 — 0.85 118 — 22 — 5.4 0.226 1.4 E4 0.63

46 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 11. Trace elements detected in ground-water samples collected for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, July to September 2006—Continued.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Samples from the twenty-two slow and intermediate wells were analyzed. All analytes are listed in table 3H. SOSA, Southern Sierra study unit 

grid-well; SOSAFP, Southern Sierra study unit flow-path well; AL-US, U.S. Environmental Protection Agency action level; HAL-US, U.S. Environmental 

Protection Agency Lifetime Health Advisory; MCL-CA, California Department of Public Health maximum contaminant level; MCL-US, U.S. Environmental 

Protection Agency maximum contaminant level; NL-CA, California Department of Public Health notification level; SMCL-CA, California Department of 

Public Health secondary maximum contaminant level; E, estimated value; LRL, laboratory reporting level; na, not available; V, analyte detected in sample and 

an associated blank thus data are not included in ground-water quality analyses; μg/L, microgram per liter; —, not detected]

GAMA 

well 

identification 

number

Lithium 

(μg/L) 

(01130) 

Manganese 

(μg/L) 

(01056) 

Molybdenum 

 (μg/L) 

(01060) 

Nickel 

(μg/L) 

(01065) 

Selenium 

(μg/L) 

(01145) 

Silver 

(μg/L) 

 (01075) 

Strontium 

(μg/L) 

(01080)

Thallium 

(μg/L) 

(01057) 

Tungsten 

(μg/L) 

(01155)

Uranium 

(μg/L) 

(22703)

Vanadium 

 (μg/L) 

(01085) 

Zinc 

(μg/L) 

(01090)

Threshold 

type1 na

SMCLCA HAL-US MCL-CA MCLUSSMCLCA HAL-US MCLUS na MCL-US NL-CA SMCLCA

Threshold 

level na 50 40 100 50 100 4,000 2 na 30 50 5,000

LRL 0.6 0.2 0.4 0.06 0.08 0.2 0.4 0.04 0.06 0.04 0.10 0.6

Grid wells

SOSA-03 46.2 0.4 2.8 3.19 0.23 — 425 — 0.46 3.98 7.1 7.2

SOSA-07 11.7 *329 6.3 0.47 — — 86.6 — 1.3 0.55 0.30 15.6

SOSA-10 91.1 *90.7 21.4 1.50 0.30 — 253 — 0.06 3.52 0.94 2.1

SOSA-13 1.0 E0.1 1.1 0.42 0.71 — 294 — 0.2 1.51 11.2 3.8

SOSA-15 5.5 — 0.4 V0.25 0.10 — 334 — 0.12 1.17 0.70 13.5

SOSA-22 2.8 0.4 — V0.07 — — 69.1 — — 0.07 0.24 V0.9

SOSA-35 98.6 3.6 14 V0.25 — — 29.7 — 1.0 0.06 — 15.4

Flow-path wells

SOSAFP-01 1.0 — 1.5 2.73 1.8 — 261 — 0.88 1.29 10.5 V1.2

SOSAFP-02 126 *2,250 4.3 2.99 — — 368 — 0.09 7.59 0.15 5.4

SOSAFP-03 2.2 — 7.8 1.67 0.59 — 223 — 5.8 0.84 15.9 2.0

SOSAFP-04 1.1 — 4.9 1.85 1.5 — 334 — 1.1 1.50 12.8 12.0

SOSAFP-05 1.7 E0.1 4.9 0.36 0.37 — 220 — 22 1.17 11.5 3.4

SOSAFP-06 1.1 — 1.2 0.68 1.1 — 260 — 0.14 1.28 11.3 1.8

SOSAFP-07 1.6 0.2 16.8 2.97 1.7 0.5 344 — — 4.75 13.6 4.8

SOSAFP-08 4.5 E0.1 14.6 2.59 1.3 — 243 — — 2.97 15.0 2.3

SOSAFP-09 — E0.1 11.0 2.70 1.1 — 313 E0.02 — 2.60 14.4 3.5

SOSAFP-10 1.5 E0.1 27.1 2.74 2.3 — 158 — — 1.31 18.8 V0.9

SOSAFP-11 E0.5 E0.1 10.4 1.76 0.31 — 202 — E0.04 0.77 16.1 3.3

SOSAFP-12 8.7 E0.1 23.8 2.94 1.6 — 173 — 0.07 0.96 16.4 2.6

SOSAFP-13 5.8 1.5 7.8 1.86 0.74 — 253 0.07 0.11 3.04 4.7 18.0

SOSAFP-14 3.5 3.2 3.8 1.94 1.3 — 310 — 0.48 4.47 6.8 2.6

SOSAFP-15 E0.4 0.3 2.8 3.83 2.4 — 263 — 0.09 2.04 7.9 15.4

 *Value above lower threshold level.

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

Tables 47
Table 12. Species of inorganic arsenic, iron, and chromium in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Analyses made by the U.S. Geological Survy Trace Metals Laboratory (laboratory entity code USGSTMCO). Samples from all fifty wells 

were analyzed for chromium; samples from the twenty-two slow and intermediate wells were analyzed for arsenic and iron; only wells with at least one 

detection are listed. Information about analytes given in table 3I. SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path 

well; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; MCL-CA, California Department of Public Health maximum contaminant level; SMCL-CA, California Department of Public Health secondary maximum contaminant level; MDL, method detection limit; V, analyte detected in 

sample and an associated blank thus data are not included in ground-water quality assessment; nc, not collected; μg/L, microgram per liter; —, not detected]

GAMA well 

identification 

number

Iron 

(μg/L) 

(01046)

Iron (II) 

 (μg/L) 

 (01047)

Arsenic 

(μg/L) 

(99033)

Arsenic (III) 

(μg/L) 

(99034)

Chromium 

(μg/L) 

(01030)

Chromium (VI) 

(μg/L) 

(01032)

Threshold type1 SMCL-CA na MCL-US na MCL-CA na

Threshold level 300 na 10 na 50 na

[MDL] 2 2 0.5 1 1 1

Grid wells

SOSA-02 nc nc nc nc 2 —

SOSA-03 4 19 *11 — 1 —

SOSA-07 *872 854 *25 12 — —

SOSA-10 223 215 V1.7 — — —

SOSA-11 nc nc nc nc 2 2

SOSA-13 — — V1.6 — 6 5

SOSA-15 — — — — — —

SOSA-22 2 — — — — —

SOSA-23 nc nc nc nc 7 5

SOSA-25 nc nc nc nc 4 5

SOSA-28 nc nc nc nc 3 2

SOSA-32 nc nc nc nc 2 —

SOSA-34 nc nc nc nc 8 6

Number of detections 9 6

Detection frequency 

(percent)

26 17

Flow-path wells

SOSAFP-01 — — V2.4 — 7 4

SOSAFP-02 *4,190 4,190 *23 7.7 — —

SOSAFP-03 3 — 2.7 — 4 3

SOSAFP-04 — — V2.4 — 3 2

SOSAFP-05 — — 2.6 — 2 1

SOSAFP-06 2 — 9.9 — 6 5

SOSAFP-07 nc nc nc nc 2 —

SOSAFP-08 — — — — 4 3

SOSAFP-09 — — 3.4 — 3 3

SOSAFP-10 2 — — — 11 9

SOSAFP-11 3 — 3.1 — 2 2

SOSAFP-12 — — — — 4 4

SOSAFP-13 14 — V1.6 — 1 —

SOSAFP-14 nc nc nc nc 2 —

SOSAFP-15 4 — 4.0 — 6 6

 *Value above threshold level.

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

48  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 13. Results for analyses of stable isotope ratios and tritium and carbon-14 activities in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006—Continued.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Laboratory entity codes are listed in the footnotes. Information about analytes given in table 3J. Samples from all fifty wells were analyzed for 

stable isotopes of water; samples from twenty–one of the slow and intermediate wells were analyzed for tritium and carbon. Stable isotope ratios are reported 

in the standard delta notation (δ), the ratio of a heavier isotope to more common lighter isotope of that element, relative to a standard reference material. 

SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; MCL-CA, California Department of Public Health maximum 

contaminant level; na, not available; nc, sample not collected; pCi/L, picocuries per liter; <, less than]

GAMA well 

identification 

number

δ2H

 (per mil) 

(82082)2

δ18O 

(per mil) 

(82085)

2

Tritium 

(pCi/L) 

(99914)3

δ13C

(per mil) 

(82081)4

Carbon–14 

(percent 

modern) 

(49933)5

Threshold type1 na na MCL–CA na na

Threshold level na na 20,000 na na

Grid wells

SOSA-01 –74.5 –10.44 nc nc nc

SOSA-02 –70.8 –9.95 nc nc nc

SOSA-03 –87.4 –11.58 10.9 –8.76 70.2

SOSA-04 –78.0 –10.06 nc nc nc

SOSA-05 –60.6 –8.60 nc nc nc

SOSA-06 –61.8 –8.92 nc nc nc

SOSA-07 –101 –13.94 7.7 –11.05 89.3

SOSA-08 –64.2 –8.67 nc nc nc

SOSA-09 –71.9 –9.98 nc nc nc

SOSA-10 –94.7 –12.70 8.0 –4.97 49.3

SOSA-11 –71.8 –9.87 nc nc nc

SOSA-12 –104 –14.20 nc nc nc

SOSA-13 –75.6 –10.55 <1 –12.41 81.9

SOSA-14 –80.3 –10.57 nc nc nc

SOSA-15 –75.5 –11.07 14.4 –16.11 90.8

SOSA-16 –79.6 –10.54 nc nc nc

SOSA-17 –78.8 –10.84 nc nc nc

SOSA-18 –76.2 –10.39 nc nc nc

SOSA-19 –74.2 –10.05 nc nc nc

SOSA-20 –77.6 –10.62 nc nc nc

SOSA-21 –77.1 –10.52 nc nc nc

SOSA-22 –92.0 –12.95 9.0 –20.75 99.4

SOSA-23 –68.8 –9.53 nc nc nc

SOSA-24 –68.8 –9.61 nc nc nc

SOSA-25 –67.0 –9.41 nc nc nc

SOSA-26 –65.9 –9.57 nc nc nc

SOSA-27 –64.6 –9.37 nc nc nc

SOSA-28 –75.4 –9.98 nc nc nc

SOSA-29 –92.8 –12.72 nc nc nc

SOSA-30 –82.2 –10.99 nc nc nc

SOSA-31 –83.6 –11.09 nc nc nc

SOSA-32 –74.1 –10.56 nc nc nc

SOSA-33 –69.3 –9.40 nc nc nc

SOSA-34 –70.8 –9.56 nc nc nc

SOSA-35 –84.8 –10.61 nc nc nc

Table 13. Results for analyses of stable isotope ratios and tritium and carbon-14 activities in samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Laboratory entity codes are listed in the footnotes. Information about analytes given in table 3J. Samples from all fifty wells were analyzed for 

stable isotopes of water; samples from twenty-one of the slow and intermediate wells were analyzed for tritium and carbon. Stable isotope ratios are reported in 

the standard delta notation (δ), the ratio of a heavier isotope to more common lighter isotope of that element, relative to a standard reference material. SOSA, 

Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; MCL-CA, California Department of Public Health maximum contaminant level; na, not available; nc, sample not collected; pCi/L, picocuries per liter; <, less than]

Tables 49
Table 13. Results for analyses of stable isotope ratios and tritium and carbon-14 activities in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006—Continued.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Laboratory entity codes are listed in the footnotes. Information about analytes given in table 3J. Samples from all fifty wells were analyzed for 

stable isotopes of water; samples from twenty–one of the slow and intermediate wells were analyzed for tritium and carbon. Stable isotope ratios are reported 

in the standard delta notation (δ), the ratio of a heavier isotope to more common lighter isotope of that element, relative to a standard reference material. 

SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; MCL-CA, California Department of Public Health maximum 

contaminant level; na, not available; nc, sample not collected; pCi/L, picocuries per liter; <, less than]

GAMA well 

identification 

number

δ2H

 (per mil) 

(82082)2

δ18O 

(per mil) 

(82085)

2

Tritium 

(pCi/L) 

(99914)3

δ13C

(per mil) 

(82081)4

Carbon–14 

(percent 

modern) 

(49933)5

Threshold type1 na na MCL–CA na na

Threshold level na na 20,000 na na

Flow–path wells

SOSAFP-01 –74.9 –10.08 <1 –11.21 63.8

SOSAFP-02 –100 –13.34 10.2 –3.35 25.0

SOSAFP-03 –75.5 –10.55 <1 –13.01 65.4

SOSAFP-04 –73.7 –10.10 1.6 –12.62 84.4

SOSAFP-05 –75.4 –10.64 <1 –13.23 63.3

SOSAFP-06 –74.5 –10.30 1.3 –10.06 76.0

SOSAFP-07 –68.3 –9.00 5.8 –11.81 103.2

SOSAFP-08 –69.4 –9.34 1.0 –12.82 83.1

SOSAFP-09 –69.1 –9.21 3.2 –12.83 98.8

SOSAFP-10 –69.0 –9.57 <1 –13.61 77.6

SOSAFP-11 –66.6 –9.12 3.2 –12.60 85.1

SOSAFP-12 –71.3 –9.78 <1 nc nc

SOSAFP-13 –75.0 –10.38 1.3 nc nc

SOSAFP-14 –75.4 –10.31 1.9 –14.59 69.5

SOSAFP-15 –73.2 –10.13 4.5 –15.42 89.8

1

Maximum contaminant level thresholds are listed as MCL–US when the MCL–US and MCL–CA are identical, and as MCL–CA when the MCL–CA is 

lower than the MCL–US or no MCL–US exists.

2

USGS Stable Isotope Laboratory, Reston, Virginia (USGSSIVA).

3

USGS Stable Isotope and Tritium Laboratory, Menlo Park, California (USGSH3CA).

4

University of Waterloo (contract laboratory) (CAN–UWIL).

5

University of Arizona, Accelerator Mass Spectrometry Laboratory (contract laboratory) (AZ–UAMSL).

50 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table 14. Radioactive constituents detected in samples collected for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. Geological Survey parameter code used to uniquely identify a specific constituent or property. Analyses made by Eberline Services (laboratory entity code CA-EBRL). Information about analytes given in table 3J. Samples from the seven 

slow wells were analyzed. SOSA, Southern Sierra study unit grid well; SOSAFP, Southern Sierra study unit flow-path well; MCL-CA, California Department 

of Public Health maximum contaminant level; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; E, estimated value; pCi/L, 

picocuries per liter; V, analyte detected in sample and an associated blank thus data are not included in ground-water quality assessment; <, less than]

GAMA well 

identification 

 number

Radium-226 

(pCi/L) 

(09511)

Radium-228

(pCi/L) 

(81366)

Radon-222 

(pCi/L) 

(82303)

Alpha 

radioactivity, 

72-hour count 

(pCi/L) 

(62636)

Alpha 

radioactivity, 

30-day count 

(pCi/L) 

(62639)

Beta 

radioactivity, 

72-hour count 

(pCi/L) 

(62642)

Beta 

radioactivity, 

30-day count 

(pCi/L) 

(62645)

Threshold type1 MCL-US MCL-US proposed 

MCL-US MCL-US MCL-US MCL-CA MCL-CA

Threshold value 2

5 25 3 300(4,000) 15 15 50 50

SOSA-03 0.15 E0.34 *E1,670 E2.6 E2.1 E3.9 E3.7

SOSA-07 0.084 E0.45 *2,240 <2.4 <2.2 E1.8 E2.4

SOSA-10 0.24 0.69 *1,480 E3.3 E2.1 E2.7 E2.3

SOSA-13 VE0.019 <0.46 250 E1.1 <3.6 <1.9 <2.9

SOSAFP-02 0.72 1.1 **4,670 11.8 E5.9 7.4 8.9

SOSAFP-05 E0.053 <0.44 E290 E0.7 <2.0 E1.6 <2.5

SOSAFP-06 E0.034 <0.59 210 E1.2 E2.5 <1.2 <2.9

 *Value above lower threshold level.

**Value above upper threshold level.

1

Maximum contaminant level thresholds are listed as MCL-US when the MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is lower 

than the MCL-US or no MCL-US exists.

2

The MCL-US threshold for radium is the sum of radium-226 and radium-228.

3

Two MCLs have been proposed for Radon-222. The proposed Alternative MCL is in parentheses.

Tables  51
Table 15. Microbial indicators detected in samples collected 

for the Southern Sierra Groundwater Ambient Monitoring and 

Assessment (GAMA) study, California, June 2006.

[The five-digit number in parentheses below the constituent name is the U.S. 

Geological Survey parameter code used to uniquely identify a specific constituent or property. Samples from the seven slow wells were analyzed. Information 

about analytes given in table 3L. SOSA, Southern Sierra study unit grid well; 

SOSAFP, Southern Sierra study unit flow path well; MCL-US, U.S. Environmental Protection Agency maximum contaminant level; mL, milliliter]

GAMA well 

identification 

number

Total 

coliforms 

colonies/ 

100mL 

(90900)

Threshold type1 MCL-US

Threshold level 5% of samples per month

SOSA-03 3

SOSA-07 1

SOSAFP-05 1

1

Maximum contaminant level thresholds are listed as MCL-US when the 

MCL-US and MCL-CA are identical, and as MCL-CA when the MCL-CA is 

lower than the MCL-US or no MCL-US exists.

52 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Appendix

Sample Collection and Analysis

Ground-water samples were collected using standard and 

modified USGS protocols (Koterba and others, 1995; U.S. 

Geological Survey, variously dated), and protocols described 

by Weiss, 1968; Shelton and others, 2001; Ball and McClesky, 

2003a,b; and Wright and others, 2005. Prior to sampling, each 

well was pumped continuously in order to purge at least three 

casing-volumes of water from the well (Wilde and others, 

1999). Wells were sampled using Teflon tubing with brass and 

stainless-steel fittings attached to a sampling point on the well 

discharge pipe as close to the well as possible. The sampling 

point was always located upstream of any well-head treatment 

system or water storage tank. If a chlorinating system was 

attached to the well, the chlorinator was shut off at least 24 

hours prior to purging and sampling the well in order to clear 

all chlorine out of the system. For the fast and intermediate 

schedules, samples were collected at the well head using a 

foot-long length of Teflon tubing. For the slow schedule, the 

samples were collected inside an enclosed chamber located 

inside a mobile laboratory and connected to the well head by 

a 10- to 50- foot length of the Teflon tubing (Lane and others, 

2003). All fittings and lengths of tubing were cleaned between 

samples (Wilde, 2004).

For the field measurements, ground water was pumped 

through a flow-through chamber fitted with a multi-probe 

meter that simultaneously measures the water-quality indicators—dissolved oxygen, temperature, pH, turbidity, and 

specific conductance. Field measurements were made in 

accordance with protocols in the USGS National Field Manual 

(Wilde and Radtke, 2005; Wilde, 2006; Lewis, 2006; Radtke 

and others, 2005; Wilde and others, 2006). All sensors on the 

multi-probe meter were calibrated daily. Measured temperature, dissolved oxygen, pH, and specific conductance values 

were recorded at 5-minute intervals for at least 30 minutes, 

and when these values remained stable for 20 minutes, samples for laboratory analyses were then collected. Field measurements and instrument calibrations were recorded by hand 

on field record sheets and electronically in PCFF-GAMA, a 

software package designed by the USGS with support from 

the GAMA program. Analytical service requests were also 

managed by PCFF-GAMA. Information from PCFF-GAMA 

was uploaded directly into NWIS at the end of every week of 

sample collection.

For analyses requiring filtered water, ground water was 

diverted through a 0.45-μm pore size vented capsule filter, a 

disk filter, or a baked glass-fiber filter depending on the protocol for the analysis (Wilde and others, 1999; Wilde and others, 

2004). Prior to sample collection, polyethylene sample bottles 

were pre-rinsed two times using deionized water, and then 

once with sample water before sample collection. Samples 

requiring acidification were acidified to a pH of 2 or less with 

the appropriate acids using ampoules of certified, traceable 

concentrated acids obtained from the USGS National Water 

Quality Laboratory (NWQL).

Temperature-sensitive samples were stored on ice prior 

to, and during, daily shipping to the various laboratories. 

The non-temperature sensitive samples for tritium, noble 

gases, chromium speciation, and stable isotopes were shipped 

monthly, while volatile organic compounds, pesticides, compounds of special interest, dissolved organic carbon, radium 

isotopes, gross alpha and beta radioactivity, and radon-222 

samples were shipped daily.

Detailed sampling protocols for individual analyses and 

groups of analytes are described in Koterba and others (2005) 

and the USGS National Field Manual (Wilde and others, 1999; 

Wilde and others, 2004) and in the references for analytical methods listed in table A1; only brief descriptions are 

given here. Volatile organic compounds (VOCs) and gasoline 

oxygenates and degradates, and 1,2,3-trichloropropane (1,2,3-

TCP) samples were collected in 40-mL sample vials that were 

purged with three vial volumes of sample water before bottom 

filling to eliminate atmospheric contamination. Six normal 

(6 N) hydrochloric acid (HCl) was added as a preservative 

to the VOC samples, but not to the gasoline oxygenate and 

degradate samples, or the 1,2,3-TCP samples. The perchlorate 

sample was collected in a 125-mL polyethylene bottle. Tritium 

samples were collected by bottom filling two 1-L polyethylene bottles with unfiltered ground water, after first overfilling the bottle with three volumes of water. Stable isotopes of 

water were collected in 60-mL clear glass bottles filled with 

unfiltered water, sealed with a conical cap, and secured with 

electrical tape to prevent leakage and evaporation.

Pesticides and pesticide degradation products, wastewater-indicator constituents, pharmaceutical compounds, and 

N-nitrosodimethylamine (NDMA) samples were collected in 

1-L baked amber bottles. Pesticide, wastewater-indicator, and 

pharmaceutical samples were filtered through a glass fiber 

during collection, whereas the NDMA samples were filtered at 

the Montgomery Watson-Harza Laboratory prior to analysis.

Appendix  53
Ground-water samples for major and minor ions, trace 

elements, alkalinity, and total dissolved solids analyses 

required filling one 250-mL polyethylene bottle with raw 

ground water, and one 500-mL and one 250-mL polyethylene 

bottle with filtered ground water (Wilde and others, 2004). 

Filtration was done using a Whatman capsule filter. The 250-

mL filtered sample was then preserved with 7.5 N nitric acid. 

Mercury samples were collected by filtering ground water into 

a 250-mL glass bottle and preserving with 6 N hydrochloric 

acid. Arsenic and iron speciation samples were filtered into 

a 250-mL polyethylene bottle that was covered with tape to 

prevent light exposure, and preserved with 6 N hydrochloric 

acid. The nutrient sample was filtered into a 125-mL brown 

polyethylene bottle. Radium isotopes and gross alpha and 

beta radiation samples were filtered into 1-L polyethylene 

bottles and acidified with nitric acid. Carbon isotope samples 

were filtered and bottom filled into two 500-mL glass bottles 

that were first overfilled with three bottle volumes of ground 

water. These samples had no headspace, and were sealed with 

a conical cap to avoid atmospheric contamination. Samples for 

alkalinity titrations were collected by filtering ground water 

into a 500-mL polyethylene bottle.

DOC, chromium, radon-222, dissolved gases, and microbial constituents were collected from the hose bib at the well 

head, regardless of the sampling schedule (fast, intermediate, or slow). DOC was collected after rinsing the sampling 

equipment with universal blank water (Wilde and others, 

2004). Using a 50-mL syringe and 0.45-μm disk filter, the 

ground-water sample then was filtered into a 125-mL baked 

glass bottle and preserved with 4.5 N sulfuric acid. Chromium 

speciation samples were collected using a 10-mL syringe with 

an attached 0.45-μm disk filter. After the syringe was thoroughly rinsed and filled with ground water, 4 mL was forced 

through the disk filter; the next 2 mL of the ground water was 

slowly filtered into a small centrifuge vial for analysis of total 

chromium. Hexavalent chromium, Cr (VI), was then collected 

by attaching a small cation exchange column to the syringe 

filter, and after conditioning the column with 2 mL of sample 

water, 2 mL was collected in a second centrifuge vial. Both 

vials were preserved with 10 μL of 7.5 N nitric acid (Ball and 

McClesky, 2003a,b).

For the collection of radon-222, a stainless steel and 

Teflon valve assembly was attached to the sampling port at the 

well head (Wilde and others, 2004). The valve was partially 

closed to create back pressure, and a 10-mL sample was taken 

through a Teflon septum on the value 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 mixture (mineral oil) and shaken. The vial was then 

placed in a cardboard tube in order to shield it from light 

during shipping.

Noble gases were collected in 3/8-in copper tubes using 

reinforced nylon tubing connected to the hose bib at the wellhead. Ground water was flushed through the tubing to dislodge 

bubbles before flow was restricted with a back pressure valve. 

Clamps on either side of the copper tube were then tightened, 

trapping a sample of ground water for analyses of noble gases 

(Weiss, 1968).

Samples for analysis of microbial constituents also were 

collected at the well head (Myers, 2004; Bushon, 2003). Prior 

to the collection of samples, the sampling port was sterilized 

using 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 sterilized 250-mL bottles 

were then filled with ground water for coliform analyses (total 

and Escherichia coliform determinations), and one sterilized 

3-L carboy was filled for coliphage analyses (F specific and 

somatic coliphage determinations).

Ten laboratories performed chemical and microbial analyses for this study (see table A1), although most of the analyses were performed at the NWQL or by labs contracted by the 

NWQL. The NWQL maintains a rigorous quality assurance 

program (Maloney, 2005; Pirkey and Glodt, 1998). Laboratory 

quality control samples, including method blanks, continuing 

calibration verification standards, standard reference samples, 

reagent spikes, external certified reference materials, and 

external blind proficiency samples, are analyzed regularly. 

Method detection limits are continuously tested and laboratory reporting levels updated accordingly. NWQL maintains 

National Environmental Laboratory Accreditation Program 

(NELAP) and other certifications (http://nwql.usgs.gov/Public/Performance/publiclabcertcoverpage.html). In addition, the 

Branch of Quality Systems within the USGS Office of Water 

Quality maintains independent oversight of quality assurance 

at the NWQL and labs contracted by the NWQL. The Branch 

of Quality Systems also runs a national field quality assurance 

program that includes annual testing of all USGS field personnel for proficiency in making field water-quality measurements (http://nfqa.cr.usgs.gov/). Results for analyses made at 

the NWQL or by laboratories contracted by the NWQL are 

uploaded directly into NWIS by the NWQL. Laboratory 

quality-control data are also stored in NWIS.

Turbidity, alkalinity, and total coliforms and Escherichia

coliform (E. coli) were measured in the mobile laboratory 

at the well site. Turbidity was measured in the field with a 

calibrated turbidity meter. Total coliforms and E. coli plates 

were prepared using sterilized equipment and reagents (Myers, 

2004). Plates were counted under an ultraviolet light, following a 22-24 hour incubation time. Alkalinity and the 

concentrations of bicarbonate (HCO3

-

) and carbonate (CO3

2-) 

were measured on filtered samples by Gran’s titration method 

(Rounds, 2006).

54 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Concentrations of HCO3

-

 and CO3

2- were also calculated 

from the laboratory alkalinity and pH measurements. Calculations were made using the advanced speciation method 

(http://or.water.usgs.gov/alk/methods.html) with pK1 = 6.35, 

pK2 = 10.33, and pKW = 14.

Data Reporting

Laboratory Reporting Conventions

The USGS NWQL uses the laboratory reporting level 

(LRL) as a threshold for reporting analytical results. The LRL 

is set to minimize the reporting of false negatives (not detecting a compound when it is actually present in a sample) to less 

than 1 percent (Childress and others, 1999). The LRL is set 

at two times the long-term method detection level (LT-MDL). 

The LT-MDL is derived from the standard deviation of at least 

24 MDL determinations made over an extended period of 

time. LT-MDLs are continually monitored and updated. The 

method detection limit (MDL) is the minimum concentration of a substance that can be measured and reported with 99 

percent confidence that the concentration is greater than zero 

(at MDL there is less than 1 percent chance of a false positive) 

(U.S. Environmental Protection Agency, 2002a). The USGS 

NWQL updates LRL values regularly and the values listed in 

this report were in effect during the period analyses were made 

for ground-water samples from the SOSA study (June and 

July, 2006).

Some compound concentrations in this study are reported 

using minimum reporting levels (MRLs) or method uncertainties. 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.

Detections between the LRL and the LT-MDL are 

reported as estimated concentrations (designated with an “E” 

before the values in the tables and text). For information-rich 

methods, detections below the LRL have high certainty of 

detection, but the precise concentration is uncertain. Information-rich methods are those that utilize gas chromatography 

or high-performance liquid chromatography (HPLC) with 

mass spectrometry detection (VOCs, gasoline oxygenates and 

degradates, pesticides, pharmaceuticals, and wastewater-indicators). Compounds are identified by presence of characteristic fragmentation patterns in their mass spectra in addition to 

being quantified by measurement of peak areas at their associated chromatographic retention times. E-values also may result 

from detections outside the range of calibration standards, 

for detections that did not meet all laboratory quality-control 

criteria, and for samples that were diluted prior to analysis 

(Childress and others, 1999).

Detections that may have resulted from sample contamination are reported with a “V” before the values in the tables. 

The potential for sample contamination was assessed using 

results from field, source, and laboratory blanks.

The reporting levels for radiochemical constituents 

(gross-alpha radioactivity, gross-beta radioactivity, radium226, and radium-228) are based on a sample-specific minimum detectable concentration (SSMDC), a sample-specific 

critical value, and the combined standard uncertainty (CSU) 

(U.S. Environmental Protection Agency, 2004; Bennett and 

others, 2006). A result above the critical value represents a 

greater-than-95-percent certainty that the result is greater than 

zero (significantly different from the instrument’s background 

response to a blank sample), and a result above the SSMDC 

represents a greater-than-95-percent certainty that the result 

is greater than the critical value. Using these reporting level 

elements, three unique cases are possible when screening the 

raw analytical data. If the analytical result is less than the 

critical value (case 1), the analyte is considered not detected, 

and the concentration is reported as less than the SSMDC. If 

the analytical result is greater than the critical value, the ratio 

of the CSU to the analytical result is calculated as a percent 

(percent relative CSU). For those samples with percent relative 

CSU greater than 20 percent, concentrations are reported as 

estimated values (designated by an “E” preceding the value) 

(case 2). For those samples with percent relative CSU less than 

20 percent, concentrations are reported unqualified (case 3).

Stable isotopic compositions of oxygen, hydrogen, and 

carbon are reported as relative isotope ratios in units of per mil 

using the standard delta notation (Coplen and others, 2002):

δ i sample

reference

i

E =

R

R

-1 1000

E is the heavier is





 



 •

where 

otope (oxygen-18, carbon-13, 

or hydrogen- 2)

R is the r sample atio of the abundance of the heavier 

isotope to the lighter isotope 

(oxygen-16, carbon-12, or hydrogen-1) 

in the sample and, 

R is the ratio of the abundance of the reference heavier 

isotope to the lighter isotope in the reference

material

The reference material for oxygen and hydrogen is 

Vienna Standard Mean Ocean Water (VSMOW), which is 

assigned δ18O and δ2H values of 0 per mil (note than δ2H is 

also written as δD because the common name of the heavier 

isotope of hydrogen, hydrogen-2, is deuterium). The reference material for carbon is Vienna Peedee Belemnite (VPDB), 

which is assigned a δ13C value of 0 per mil. Positive values 

indicate enrichment of the heavier isotope and negative values 

indicate depletion of the heavier isotope, compared to the 

ratios observed in the standard reference material.

Appendix  55
Constituents on Multiple Analytical Schedules

Twenty-seven constituents targeted in this study are measured by more than one analytical schedule or more than one 

laboratory (table A2). Results from certain analytical schedules are preferred over others because the methodology is 

more accurate or precise and generally yields greater sensitivity for a given compound.

The preferred methods for the nineteen constituents analyzed under multiple analytical schedules at the NWQL were 

selected based on the procedure recommended by the NWQL 

(http://wwwnwql.cr.usgs.gov/USGS/Preferred_method_selection_procedure.html). This procedure generally results in the 

preferred method being the one with the lower reporting limit. 

The nineteen constituents each appear on two of the following 

analytical schedules: VOCs (Schedule 2020), gasoline oxygenates and degradates (Schedule 4024), pesticides (Schedule 

2003), pharmaceutical compounds (Schedule 2080), and 

wastewater-indicator compounds (Schedule 1433) (table A2). 

Only the values determined by the preferred method are 

reported. This report uses Schedule 2080 (table 3D) as the preferred method for caffeine because it has the lower detection 

limit and for data consistency; however, as of 2007, NWQL 

considered Schedule 1433 (table 3E) the preferred method 

because Schedule 2080 only became an NWQL method in 

2005 and therefore has a relatively short history of qualityassurance data. All ground-water samples were analyzed for 

pharmaceuticals (Schedule 2080), but only six were analyzed 

for wastewater-indicator constituents (Schedule 1433).

The water-quality indicators—pH, specific conductance, 

and alkalinity—were measured in the field and at the NWQL. 

The field measurements are the preferred method for all three 

constituents; however, laboratory alkalinity results were used 

in this report because fewer samples had field alkalinity 

measurements.

The field and laboratory data were compared using the 

Wilcoxon signed-rank test, a non-parametric statistical test 

that is analogous to the parametric statistical test, the paired 

t-test (Helsel and Hirsch, 2002). A non-parametric test was 

used because the data are not normally distributed. The Wilcoxon signed-rank test evaluates the null hypothesis that the 

median of the paired differences between the two data sets is 

zero. Results are reported as the probability, P, of obtaining the 

observed distribution of data, or one even less likely, when the 

null hypothesis is true. Therefore, a P value of 0.01 indicates 

99 percent confidence that the two data sets are different.

Specific conductance was measured in both the field and 

the laboratory for twenty-two samples, and there was no difference between the two data sets (P = 0.19). Both laboratory 

and field pH measurements were made for ten samples, and 

the two data sets were systematically different (P = 0.006). 

Field pH values were lower by a median of 0.3 pH units. 

The increase in pH between field and laboratory measurement may be explained by equilibration of the sample with 

the atmosphere after collection. The partial pressure of CO2

in ground water is often greater than the atmospheric partial 

pressure (Appelo and Postma, 2005), thus CO2 degasses from 

the ground water when it is brought in contact with the atmosphere. CO2

 loss results in increased pH. Field and laboratory 

alkalinities were measured for seven samples, and the two data 

sets were not significantly different (P = 0.035). Field alkalinity values were lower by a median of 5 mg/L as CaCO3

, but 

the differences between the field and laboratory values were 

less than 4 percent for all but one sample, which was within 

the error of the alkalinity measurement (Rounds, 2006).

For arsenic, chromium, and iron concentrations, the 

standard methods used by the NWQL are preferred over the 

research methods used by the USGS Trace Metal Laboratory. 

The concentrations measured by the Trace Metal Laboratory 

are used only to calculated ratios of redox species for each 

element, As(V)

As(III)

for arsenic, Cr(VI)

Cr(III)

 for chromium, and Fe(III)

Fe(II)

for iron. For example:

Fe(III)

Fe(II)

Fe(T) - Fe(II)

Fe(II)

where 

Fe(T) is the total i

=

ron concentration (measured)

Fe(II) is the concentration of ferrous iron (measured)

Fe(III) is the concentration of ferric iron (calculated).

Quality Assurance

Blanks

Blank samples (blanks) were collected using water 

(Nitrogen-Purged Universal blank water) certified by the 

NWQL to contain less than the LRL or MRL of the analytes 

investigated in the study. Two types of blanks were collected: 

source-solution and field blanks. Source-solution blanks 

were collected to verify that the blank water used for the field 

blanks was free of analytes. Field blanks were collected at 12 

percent of the wells sampled and source solution blanks at 8 

percent of the wells sampled to determine if equipment or procedures used in the field or laboratory introduced contamination. Field blanks were analyzed for VOCs; gasoline oxygenates and degradates; pesticides; pharmaceuticals; perchlorate; 

NDMA; 1,2,3-TCP; nutrients; dissolved organic carbon; major 

and minor ions; trace elements; iron, arsenic, and chromium 

speciation; and radioactive constituents (table A3). Universal 

blank water is not available for tritium or noble gases, thus 

field blanks were not collected for these constituents.

56 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Source-solution blanks were collected at the sampling 

site by pouring blank water directly into sample containers 

that were preserved, stored, shipped, and analyzed in the same 

manner as the ground-water samples. For field blanks, blank 

water was either pumped or poured through the sampling 

equipment (fittings and tubing) used to collect ground water, 

then processed and transported using the same protocols for 

the ground-water samples. The equipment used to collect 

samples from wells on the slow schedule was different than 

the equipment used to collect samples from wells on the fast 

and intermediate schedules; therefore, detections in field 

blanks collected at slow wells were compared with detections 

in ground-water samples from slow wells, and detections in 

field blanks collected at fast and intermediate wells were compared with detections in ground-water samples from fast and 

intermediate wells.

If a constituent was detected in a field blank, the associated source-solution blank results were examined for similar 

constituent detections. If the field blank and the source-solution blank contained the constituent, then the source solution 

water was interpreted as the origin of the contamination in the 

blanks, and the field blank detections using the same blank 

water were disregarded. If the sample collected just prior to 

the contaminated field blank had high concentrations of the 

constituents in question, carry-over was considered to be the 

cause of the contamination.

If the presence of a constituent in a field blank could not 

be accounted for by contamination of the source-solution, 

carry-over, or a specific problem recorded in the field notes, 

then that field blank detection was used to censor detections in 

all ground-water samples collected with the same equipment. 

The censoring level was defined as the concentration of the 

constituent in the field blank plus one-half the LRL for that 

constituent. Detections in ground-water samples below the 

censoring level were censored. Censored values are indicated 

by a ‘V’ preceding the value in the tables, and are excluded 

from the summary statistics.

Replicates

Sequential replicate samples were collected to assess 

variability that may result from the processing and analyses of 

inorganic and organic constituents. Relative standard deviation (RSD) of the measured values was used in determining 

the variability between replicate pairs for each compound 

(tables A4A–D). 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 (Hamlin and others, 2002). Values of RSD less than 

20 percent are considered acceptable in this study. An RSD 

value of 20 percent corresponds to a relative percent difference 

(RPD) value of 29 percent. High RSD values for a compound 

may indicate analytical uncertainty at low concentrations, 

particularly for concentrations within an order of magnitude of 

LT-MDL or MDL. Sequential replicate samples were collected 

at 18 percent of the wells sampled.

Matrix Spikes

Addition of a known concentration of a constituent 

(‘spike’) to a replicate environmental sample enables the analyzing laboratory to determine the effect of the matrix, in this 

case ground water, on the analytical technique used to measure 

the constituent. 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 were added at the laboratory 

performing the analysis. Compounds with low recoveries are 

of potential concern if environmental concentrations are close 

to the MCLs; a concentration below an MCL could be falsely 

indicated. Conversely, compounds with high recoveries are of 

potential concern if the environmental concentrations exceed 

MCLs: a high recovery could falsely indicate a concentration 

above the MCL.

Acceptable ranges for matrix-spike recoveries are based 

on the acceptable ranges established for laboratory “set” spike 

recoveries. Laboratory set spikes are aliquots of laboratory 

blank water to which the same spike solution used for the 

matrix spikes has been added. One set spike is analyzed with 

each set of samples. Acceptable ranges for set spike recoveries are 70 to 130 percent for NWQL schedules 2020, 4024, 

and 1433 (Connor and others, 1998; Rose and Sandstrom, 

2003; Zaugg and others, 2002), 60 to 120 percent for NWQL 

schedule 2003 (Sandstrom and others, 2001), and 60 to 130 

percent for schedule 2080 (Kolpin and others, 2002). Based on 

these ranges, we defined 70 to 130 percent as the acceptable 

range for matrix-spike recoveries for organic compounds in 

this study.

Matrix spikes were performed for VOCs, gasoline oxygenates and degradates, pesticides, pharmaceuticals, wastewater-indicators, NDMA, and 1,2,3-TCP because the analytical 

methods for these constituents are chromatographic methods 

that may be susceptible to matrix interferences. Replicate samples for matrix-spike additions were collected at 12 percent of 

the wells sampled, although not all analyte classes were tested 

at every well (tables A5A–E).

Appendix  57
Surrogates

Surrogate compounds are added to environmental samples in the laboratory prior to analysis in order to evaluate the 

recovery of similar constituents. Surrogate compounds were 

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

were analyzed for VOCs, gasoline oxygenates and degradates, 

pesticides, pharmaceuticals, wastewater-indicators, NDMA, 

and 1,2,3-TCP (table A6). Most of the surrogate compounds 

are deuterated analogs of compounds being analyzed. For 

example, the surrogate toluene-d8 used for the VOC analytical method has the same chemical structure as toluene, except 

that the eight hydrogen-1 atoms on the molecule have been 

replaced by deuterium (hydrogen-2). Toluene-d8 and toluene 

behave very similarly in the analytical procedure, but the small 

mass difference between the two results in slightly different 

chromatographic retention times, thus the use of a toluene-d8 

surrogate does not interfere with the analysis of toluene (Grob, 

1995). Only 0.015 percent of hydrogen atoms are deuterium 

(Firestone and others, 1996), thus deuterated compounds 

like toluene-d8 do not occur naturally and are not found in 

environmental samples. Surrogates are used to identify general 

problems that may arise during sample analysis that could 

affect the analysis results for all compounds in that sample. 

Potential problems include matrix interferences (such as high 

levels of dissolved organic carbon) that produce a positive 

bias, or incomplete laboratory recovery (possibly due to 

improper maintenance and calibration of analytical equipment) 

that produces a negative bias. A 70 to 130 percent recovery of 

surrogates is generally considered acceptable; values outside 

this range indicate possible problems with the processing and 

analysis of samples (Connor and others, 1998; Sandstrom and 

others, 2001).

Quality-Control Sample Results

Detections in Field and Source-Solution Blanks

Field blanks were collected at approximately 12 percent 

of the sites sampled in SOSA. Table A3 presents a summary 

of detections in field blanks. The only VOC observed in 

field blanks was toluene. Toluene was detected in one of the 

six field blanks at a concentration of E0.02 μg/L. The field 

blank with the detection was collected using the “fast” and 

“intermediate” schedule equipment. However, low levels of 

toluene have been detected in source-solution and field blanks 

collected using both the “slow” and “intermediate” and “fast” 

equipment sets in many of the earlier study units (Wright and 

others, 2005; Kulongoski and others, 2006; Bennett and others, 2006; Dawson and others, 2007; Kulongoski and Belitz, 

2007). Thus, the detection in the field blank was used to 

censor data collected using both equipment sets. Toluene was 

detected at a concentration of E0.02 μg/L in two ground-water 

samples; both of these detections were censored (tables 5 and 

A3).

Field blanks were collected at three of the twenty-two 

sites sampled for analysis of trace elements. Chromium was 

detected in all three field blanks at concentrations of E0.02, 

E0.02, and E0.03 μg/L. The field blank with a chromium 

concentration of E0.03 μg/L was accompanied by a sourcesolution blank that also had a concentration of E0.03 μg/L. 

The lowest concentration detected in ground-water samples 

was 0.04 μg/L; thus, no chromium data were censored on the 

basis of detections in the field blanks. Zinc was detected in 

two of three field blanks at concentrations of E0.5 μg/L and 

1.40 μg/L. Three detections of zinc in ground-water samples 

with concentrations less than 1.7 μg/L (1.4 μg/L plus one-half 

the LRL of 0.6 μg/L) were therefore censored (tables 11 and 

A3). Barium and lead were each detected in one field blank, 

but at concentrations lower than found in the environmental 

samples, thus no data were censored. Copper and nickel were 

detected in one field blank at concentrations of 0.94 μg/L and 

0.29 μg/L, respectively. The field blank containing copper and 

nickel and was collected using the “intermediate” schedule 

equipment. Six detections of copper in ground-water samples 

collected using the “intermediate” schedule equipment with 

concentrations less than 1.1 μg/L (0.94 μg/L plus one-half the 

LRL of 0.4 μg/L), and three detections of nickel with concentrations less than 0.32 μg/L (0.29 μg/L plus one-half the LRL 

of 0.03 μg/L) were therefore censored (tables 11 and A3). This 

resulted in censoring of three detections of copper and one 

detection of nickel in ground-water samples (tables 11 and 

A3).

Field blanks were collected at five of the fifty sites 

sampled for chromium species analysis at the USGS Trace 

Metal Laboratory (TML) and two of the twenty-two sites 

sampled for arsenic and iron species at the TML. One sourcesolution blank was collected for chromium, iron, and arsenic 

species analysis. None of the field or source-solution blanks 

contained iron or chromium. One field blank contained 2.3 

μg/L of arsenic. The source-solution blank contained 4.3 μg/L 

of arsenic, but arsenic was not detected in the source solution 

blank and field blank collected at the same time for analysis 

by the NWQL. Five detections of arsenic in ground-water 

samples analyzed by the TML at concentrations less than 

2.55 μg/L (2.3 mg/L plus one-half the MDL of 0.5 mg/L) were 

censored (tables 12 and A3).

DOC was detected in one field blank at a concentration of 

E0.2 mg/L, and low concentrations of DOC were detected in 

field blanks collected in previous GAMA study units (Kulongoski and Belitz, 2007; Bennett and others, 2006). Thus, the 

data for all ground-water samples with concentrations of 

E0.2 mg/L and E0.3 mg/L were censored (tables 9 and A3).

One field blank was collected for analysis of radioactive constituents. Radium-226 was detected at an activity of 

E0.02 pCi/L in the field blank. The one detection of radium226 at an activity less than the activity measured in the blank 

58  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
was censored (table 15 and A3). No other radioactive constituents were detected in the field blank.

No compounds were detected in field blanks for the 

following analyte groups: pesticides and pesticide degradates 

(five field blanks), pharmaceutical compounds (six field 

blanks), wastewater-indicator compounds (one field blank), 

perchlorate (three field blanks), NDMA and 1,2,3-TCP (two 

field blanks), major and minor ions (three field blanks), and 

nutrients (three field blanks).

Variability in Replicate Samples

Tables A4A–D summarize the results of replicate analyses for constituents detected in ground-water samples collected 

in the SOSA study. Nearly 300 replicate analyses were made 

for constituents detected in at least one ground-water sample. 

Replicate analyses that were non-detections are not reported in 

tables A4A–D. Concentrations or activities in the environmental and replicate samples are reported for all replicate analyses 

with RSD values greater than zero. Most replicate analyses 

had RSD values less than 5 percent and only twelve had 

RSD values greater than the acceptable limit of 20 percent. 

Constituents with replicate analyses with RSD values greater 

than 20 percent include acetaminophen (tableA4A), perchlorate (table A4A), DOC (table A4B), aluminum (table A4C), 

zinc (table A4C), tritium (table A4D), and iron, arsenic, and 

chromium analyzed by the USGS Trace Metal Laboratory 

(table A4C). However, with the exception of one zinc replicate 

analysis, the magnitudes of the concentrations of the replicate 

sample pairs with RSD values greater than 20 percent were all 

within a factor of five of the LRLs for the respective analytes. 

At these low concentrations, small deviations in measured 

values result in large RSDs. The tritium replicate analyses 

were within laboratory analytical uncertainty of one another. 

Only four replicate analyses included one detection and one 

non-detection (aluminum, acetaminophen, and iron and arsenic analyzed at the Trace Metal Laboratory) and the detected 

concentrations were less than twice the LRLs. No data were 

censored as a result of variability in replicate analyses.

Matrix-Spike Recoveries

Tables A5A–E present a summary of matrix-spike 

recoveries for the SOSA study. Addition of a spike or known 

concentration of a constituent to an environmental sample 

enables the analyzing laboratory to determine the effect of the 

matrix, in this case ground water, on the analytical technique 

used to measure the constituent. Six environmental samples 

were spiked with VOCs to calculate matrix-spike recoveries (table A5A). Sixty-eight of the eighty-eight VOC spike 

compounds had recoveries within the acceptable range of 70 

and 130 percent. Fifteen VOC spike compounds had at least 

one matrix-spike recovery greater than 130 percent; however, 

only two of these compounds were detected in ground-water 

samples. All six matrix-spike recoveries for carbon 

tetrachloride (tetrachloromethane) were greater than 130 percent (median 188 percent), suggesting that measured concentrations in environmental samples may be disproportionately 

high. An “E” code was given to the one detection of carbon 

tetrachloride to indicate that the magnitude of the concentration is uncertain (table 5). Of the six matrix spikes for trichlorofluoromethane (CFC-11) only two had recoveries greater 

than 130 percent and neither of the two environmental samples 

with trichlorofluoromethane detections was analyzed in the 

same batch as the matrix spike with high recoveries. Thus, the 

trichlorofluormethane detections were not flagged. Dichlorodifluoromethane, dichloromethane, 1,2,3,4-tetramethybenzene, 1,2,3,5-tetramethylbenzene, and 1,2,3-trichlorobenzene 

had median matrix-spike recoveries below 70 percent, but 

these compounds were not detected in ground-water samples 

(table 12). [NOTE – low recoveries may indicate that the compound might not have been detected in some samples if it was 

present at very low concentrations].

Five ground-water samples were spiked with pesticide 

and pesticide degradate compounds in order to calculate 

matrix-spike recoveries. Twenty-eight of the sixty-three spike 

compounds had recoveries within the acceptable range of 

70 and 130 percent (table A5B). All five of the compounds 

detected in ground-water samples had spike recoveries within 

the acceptable range. Three spike compounds had at least one 

recovery greater than 130 percent. Thirty-three spike compounds had at least one recovery below 70 percent, and the 

median recovery was below 70 percent for fifteen compounds. 

[NOTE – low recoveries may indicate that the compound 

might not have been detected in some samples if it was present 

at very low concentrations].

Four ground-water samples were spiked with pharmaceutical compounds. Eight of the fourteen pharmaceutical 

compounds had recoveries within the acceptable range of 70 

to 130 percent, and six compounds had recoveries less than 

70 percent for at least one of the four tests (table A5C). Two 

compounds detected in ground-water samples, diphenhydramine and sulfamethoxazole, had low recoveries in all four 

spiked samples. [NOTE – low recoveries may indicate that the 

compound might not have been detected in some samples if it 

was present at very low concentrations].

One ground-water sample was spiked with wastewaterindicator compounds. Sixteen of the sixty-two compounds 

had recoveries less than 70 percent and one had recovery 

greater than 130 percent (table A5D). One of the compounds 

detected in ground-water samples, tetrachloroethene (PCE), 

had a recovery of only 15 percent, but the wastewater-indicator 

analytical method (NWQL schedule 1433) is not the preferred 

analytical method for tetrachloroethene (table A2).

Appendix  59
Three ground-water samples were spiked with NDMA 

and 1,2,3-TCP. All spike recoveries were within the acceptable 

range of 70 to 130 percent (table A5E).

Surrogate Compound Recoveries

Surrogate compounds were added to environmental samples in the laboratory and analyzed to evaluate the recovery 

of similar constituents. Table A6 lists the surrogate, analytical 

schedule on which it was applied, the number of analyses for 

blank and non-blank samples, the number of surrogate recoveries below 70 percent, and the number of surrogate recoveries 

above 130 percent for the blank and non-blank samples. Blank 

and non-blank samples were considered separately to assess 

whether the matrices present in non-blank samples affect surrogate recoveries. No systematic differences between surrogate 

recoveries in blank and non-blank samples were observed. 

All surrogate recoveries in analyses of pharmaceutical compounds were in the acceptable range of 70 to 130 percent 

recovery, as were 90 percent of the surrogate recoveries for 

VOC and gasoline oxygenate and degradate analyses, and 93 

percent of the surrogate recoveries for pesticide, NDMA, and 

1,2,3-TCP analyses. Two-thirds of the surrogate recoveries 

for wastewater-indicator constituent analyses were in the 

acceptable range.

Three environmental samples with detections of VOCs 

had recoveries of the surrogate 1,2-dichloroethane-d4 greater 

than 130 percent. The three VOCs detected in these three 

samples all elute near 1,2-dichloroethane-d4 in the chromatographic sequence. A high recovery for a surrogate suggests 

that the measured concentrations of analytes eluting near the 

surrogate may be biased to higher concentrations. All three 

detections already had ‘E’ codes, thus no additional flagging 

was needed.

Internal Laboratory Quality-Control Samples for 

Pharmaceutical Compounds

The protocols for analysis of pharmaceutical compounds 

(NWQL schedule 2080) has been used for routine sample 

analysis since October 2005, but due to the newness of the 

method compared with the other methods of analysis used in 

this study, an extra level of quality-control assessment was 

applied to the pharmaceutical data. In addition to the results 

for field blanks, matrix-spike recoveries, surrogates recoveries, 

and replicate variability, results for internal laboratory quality-control samples that were run with SOSA ground-water 

samples were compiled and examined. The fifty ground-water 

samples were analyzed in eleven different laboratory sets. 

Each set also included a set blank and a set spike. Purified 

water (de-ionized, carbon-filtered, and ultraviolet-radiation 

sterilized) was used for the set blanks and the matrix water for 

the set spikes (Kolpin and others, 2002).

Ten of the eleven set blanks had no detections of any 

pharmaceutical compounds. Diphenhydramine and carbamazapine were detected in one set blank at concentrations of 

E0.0005 μg/L and E0.0006 μg/L, respectively (table A7A). 

Detections in a set blank may indicate contamination of laboratory equipment that may affect other samples analyzed in 

the same set. Diphenhydramime and carbamazapine were each 

detected once in ground-water samples analyzed in the same 

set as the set blank containing those constituents. The concentrations in the ground-water samples were more than ten times 

the concentrations in the set blanks, thus the detections in the 

ground-water samples were not censored on this basis. However, examination of set blanks for laboratory sets containing 

GAMA ground-water samples collected between October 

2005 and March 2007 showed that diphenhydramine was 

consistently detected in more than 20 percent of the set blanks. 

Due to this unacceptably high rate of low-level contamination, 

all detections of diphenhydramine were censored, even if the 

concentration in the ground-water sample was more than ten 

times greater than the concentration in the set blanks.

Recoveries of spike constituents in the set spike samples 

(table A7B) were similar to those in the ground-water matrixspike samples (table A5C). Six of the fourteen pharmaceutical 

compounds had recoveries within the acceptable range of 70 

to 130 percent in all eleven set spikes. Of the remaining eight 

60 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A1. Analytical methods used for the determination of organic, inorganic, and microbial constituents by the U.S. Geological 

Survey (USGS) National Water Quality Laboratory (NWQL) and additional contract laboratories—Continued.

[MI agar, supplemented nutrient agar in which coliforms (total and Escherichia) produce distinctly different fluorescence under ultraviolet lighting; UV, 

ultraviolet; VOCs, volatile organic compounds]

Analyte Analytical 

Method

Laboratory and 

analytical 

schedule

Citation(s)

Water-quality indicators

Field parameters USGS field measurementU.S. Geological Survey, variously dated

Organic constituents

VOCs Purge and trap capillary gas chromatography/mass spectrometryNWQL, schedule 2020 Connor and others, 1998

Gasoline oxygenates Heated purge and trap/gas chromatography/mass spectrometry NWQL, schedule 4024 Rose and Sandstrom, 2003

Pesticides Solid-phase extraction and gas chromatography/mass spectrometryNWQL, schedule 2003 Zaugg and others, 1995; Lindley and others, 

1996; Madsen and others, 2003; Sandstrom and 

others, 2001

Pharmaceuticals Solid-phase extraction and HPLC/mass 

spectrometry

NWQL, schedule 2080 Kolpin and others, 2002

Wastewater-indicators Solid-phase extraction and gas chromatography/mass spectrometryNWQL, schedule 1433 Zaugg and others, 2002

Constituents of special interest

Perchlorate Chromatography and mass spectrometry Montgomery WatsonHarza LaboratoryHautman and others, 1999

N-nitrosodimethylamine (NDMA)

Chromatography and mass spectrometry Montgomery WatsonHarza LaboratoryU.S. Environmental Protection Agency, 1996; 

U.S. Environmental Protection Agency, 1999

1,2,3-Trichloropropane Gas chromatography/electron capture 

detector

Montgomery WatsonHarza LaboratoryU.S. Environmental Protection Agency, 1995

Inorganic constituents

Nutrients Alkaline persulfate digestion, Kjedahl 

digestion

NWQL, schedule 2755 Fishman, 1993; Patton and Kryskalla, 2003

Dissolved organic 

carbon

UV-promoted persulfate oxidation and 

infrared spectrometry

NWQL, schedule 2613 Brenton and Arnett, 1993

Major and minor ions, 

trace elements and 

nutrients

Atomic absorption spectrometry, colorimetry, ion-exchange chromatography, 

inductively-coupled plasma atomic 

emission spectrometry and mass spectrometry

NWQL, schedule 1948 Fishman and Friedman, 1989; Fishman, 1993; 

Faires, 1993; McLain, 1993; Garbarino, 1999; 

Garbarino and Damrau, 2001; American Public 

Health Association, 1998; Garbarino and others, 2006

Chromium, arsenic and 

iron speciation

Various techniques of ultraviolet visible 

(UV-VIS) spectrophotometry and 

atomic absorbance spectroscopy

USGS Trace Metal 

Laboratory, Boulder, 

Colorado

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

McCleskey, 2003a and 2003b; McCleskey and 

others, 2003

Stable isotopes

Stable isotopes of 

water

Gaseous hydrogen and carbon dioxidewater equilibration and stable-isotope 

mass spectrometry

USGS Stable Isotope 

Laboratory, Reston, 

Virginia

Epstein and Mayeda, 1953; Coplen and others, 

1991; Coplen, 1994

Carbon isotopes Accelerator mass spectrometry University of Waterloo, 

Environmental Isotope Lab; University 

of Arizona Accelerator Mass Spectrometry Lab

Donahue and others, 1990; Jull and others, 2004

Table A1. Analytical methods used for the determination of organic, inorganic, and microbial constituents by the U.S. Geological 

Survey (USGS) National Water Quality Laboratory (NWQL) and additional contract laboratories.

[MI agar, supplemented nutrient agar in which coliforms (total and Escherichia) produce distinctly different fluorescence under ultraviolet lighting; UV, ultraviolet; VOCs, volatile organic compounds]

Appendix Tables 61
Table A1. Analytical methods used for the determination of organic, inorganic, and microbial constituents by the U.S. Geological 

Survey (USGS) National Water Quality Laboratory (NWQL) and additional contract laboratories—Continued.

[MI agar, supplemented nutrient agar in which coliforms (total and Escherichia) produce distinctly different fluorescence under ultraviolet lighting; UV, 

ultraviolet; VOCs, volatile organic compounds]

Analyte Analytical 

Method

Laboratory and 

analytical 

schedule

Citation(s)

Radioactivity and gases

Tritium Electrolytic enrichment-liquid scintillationUSGS Stable Isotope 

and Tritium Laboratory, Menlo Park, 

California

Thatcher and others, 1977

Tritium and noble 

gases

Helium-3 in-growth and mass spectrometryLawrence Livermore 

National Laboratory

Moran and others, 2002; Eaton and others, 2004

Radon-222 Liquid scintillation counting NWQL, schedule 1369 American Society for Testing and Materials, 1998

Radium 226/228 Alpha activity counting Eberline Analytical 

Services, NWQL 

schedule 1262

Krieger and Whittaker, 1980

Gross alpha and beta 

radioactivity

Alpha and beta activity counting Eberline Analytical 

Services, NWQL 

schedule 1792

Krieger and Whittaker, 1980

Microbial constituents

F-specific and somatic 

coliphage

Single-agar layer (SAL) and two-step 

enrichment methods

USGS Ohio Water 

Microbiology Laboratory

U.S. Environmental Protection Agency, 2001

Total and Escherichia 

coliform

Membrane filter technique with “MI 

agar”

USGS field measurementU.S. Environmental Protection Agency, 2002b

62 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A2. Preferred analytical schedules for constituents appearing on multiple schedules for samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006

[Preferred analytical schedules are the methods of analysis with the greatest accuracy and precision out of the ones used for the compound in 

question. LLNL, Lawrence Livermore National Laboratory; MWH, Montgomery Watson Harza Laboratory; SITL, U.S. Geological Survey 

Stable Isotope and Tritium Laboratory; TML, U.S. Geological Survey Trace Metal Laboratory; VOC, volatile organic compound]

Constituent

Primary 

constituent 

classification

Analytical 

schedules

Preferred 

analytical 

schedule

Results from preferred method reported

Acetone VOC, gasoline degradate 2020, 4024 2020

Bromoform VOC 2020, 1433 2020

Caffeine Wastewater indicator 2080, 1433 2080

Carbaryl Pesticide 2003, 1433 2003

Chlorpyrifos Pesticide 2003, 1433 2003

Cotitine Wastewater indicator 1433, 2080 2080

Diazinon Pesticide 2003, 1433 2003

1,4-Dichlorobenzene VOC, pesticide 2020, 1433 2020

Dichlorvos Pesticide 1433, 2003 2003

Diisopropyl ether VOC, gasoline oxygenate 2020, 4024 2020

Ethyl tert-Butyl ether (ETBE) VOC, gasoline oxygenate 2020, 4024 2020

Isopropylbenzene VOC 2020, 1433 2020

Metalaxyl Pesticide 2003, 1433 2003

Methyl tert-butyl ether (MTBE) VOC, gasoline oxygenate 2020, 4024 2020

Methyl tert-pentyl ether VOC, gasoline oxygenate 2020, 4024 2020

Metolachlor Pesticide 2003, 1433 2003

Naphthalene VOC 2020, 1433 2020

Prometon Pesticide 2003, 1433 2003

Tetrachloroethene (PCE) VOC 2020, 1433 2020

Results from both methods reported

Alkalinity Water-quality indicator 1948, field field

Arsenic, total Trace element 1948, TML 1948

Chromium, total Trace element 1948, TML 1948

Iron, total Trace element 1948, TML 1948

pH Water-quality indicator 1948, field field

Specific conductance Water-quality indicator 1948, field field

1,2,3-Trichloropropane (1,2,3-TCP) VOC 2020, MWH MWH

Tritium Radioactive LLNL, SITL both

Appendix Tables 63
 Table A3. Constituents detected in field blanks collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment 

(GAMA) study, California, June 2006.

[Censored data are reported but not used in summary statistics; E, estimated value; pCi/L, picocuries per liter; mg/L, milligrams per liter; μg/L, micrograms per 

liter, — not detected]

Constituent

Slow Schedule Fast and Intermediate Schedule

Number of field 

blank detections/

analyses

Concentration 

detected in field 

blanks

Number of groundwater samples 

censored

Number of field 

blank detections/

analyses

Concentration 

detected in field 

blanks

Number of groundwater samples 

censored

Organic constituents (mg/L)

Toluene 0/1 — 1 1/5 E0.02 1

Nutrients (mg/L)

Dissolved organic 

carbon

0/1 — 3 1/2 E0.2 6

Inorganic constitutents (μg/L)

Barium 0/1 — 0 1/2 E0.12 2

Chromium 1/1 E0.03 0 2/2 E0.02, E0.02 0

Copper 0/1 — 0 1/2 0.94 6

Lead 0/1 — 0 1/2 0.1 0

Nickel 0/1 — 0 1/2 0.29 3

Zinc 1/1 E0.5 0 1/2 1.4 3

Arsenic (TML)1 0/0 — 2 1/2 2.3 3

Radioactive constituents (pCi/L)

Radium-226 1/1 E0.02 1 0/0 — 0

1

Arsenic analyses made by U.S. Geological Survey Trace Metal Laboratory (80093).

64 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A4A. Quality-control summary for replicate analyses of organic constituents detected in samples collected for the Southern 

Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[RSD, relative standard deviation in percent; nd, not detected; μg/L, micrograms per liter]

Constituent

Number of 

RSDs greater 

than zero/

number of 

replicates

Maximum 

RSD 

(percent)

Median 

RSD 

(percent)

Concentrations for 

replicates with 

RSD greater 

than zero 

(environmental/

replicate) 

(mg/L)

Volatile organic compounds and gasoline oxygenates (Schedules 2020 and 4204)

Chloroform 0/5 0 0

1,2-Dichlorobenzene 0/5 0 0

cis-1,2-Dichloroethene 0/5 0 0

1,2-Dichloropropane 0/5 0 0

Methyl tert-butyl ether (MTBE) 0/5 0 0

Tetrachloroethene (PCE) 1/5 3 0 (0.23, 0.24)

Tetrachloromethane 0/5 0 0

Toluene 0/5 0 0

Trichloroethene (TCE) 0/5 0 0

Trichlorofluoromethane 0/5 0 0

1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113) 0/5 0 0

Pesticides and pesticide degradates (Schedule 2003)

Atrazine 0/8 0 0

Deethylatrazine 0/8 0 0

Fipronil sulfide 0/8 0 0

Prometon 0/8 0 0

Simazine 0/8 0 0

Pharmaceuticals (Schedule 2080)

Acetaminophen 1/8 99 0 (nd, 0.034)

Caffeine 0/8 0 0

Carbamazapine 0/8 0 0

Sulfamethoxazole 0/8 0 0

Constituents of Special Interest 

Perchlorate 2/5 23 0.0 (0.92, 0.66), (0.69, 0.77)

1,2,3 - Trichloropropane 0/3 0.0 0.0

N-Nitrosodimethylamine 0/3 0.0 0.0

Appendix Tables 65
Table A4B. Quality-control summary for replicate analyses of major and minor ions and nutrients detected in samples collected for 

the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[RSD, relative standard deviation in percent; mg/L, milligrams per liter]

Constituent

Number of 

RSDs greater 

than zero/

number of 

replicates

Maximum 

RSD 

(percent)

Median 

RSD 

(percent)

Concentrations for 

replicates with 

RSD greater 

than zero 

(environmental/

replicate) 

(mg/L)

Major and minor ions

Calcium 3/3 2.2 0.1 (42.5, 41.2), (56.3, 56.2), (66.5, 66.6)

Magnesium 3/3 2.1 1.4 (6.95, 6.75), (15.2, 15.5), (9.06, 9.08)

Potassium 3/3 1.6 1.5 (1.36, 1.39), (3.40, 3.48), (0.78, 0.77)

Sodium 3/3 1.8 0.4 (35.4, 34.5), (24.1, 24.0), (33.1, 33.3)

Bromide 0/0 0 0

Chloride 2/3 0.5 0.4 (14.7, 14.8), (17.7, 17.8)

Fluoride 1/3 20 0 (0.4, 0.3)

Iodide 0/1 0 0

Sulfate 1/3 0.2 0 (45.4, 45.5)

Silica 2/3 0.3 0.2 (46.7, 46.6), (23.9, 24.0)

Total dissolved solids 1/3 0.3 0 (256, 257)

Residue on evaporation 2/3 0.5 0.4 (266, 264), (341, 343)

Nutrients and dissolved organic carbon

Dissolved organic carbon 2/3 28 20 (0.3, 0.2), (0.4, 0.3)

Phosphorus 1/3 3.4 0 (0.21, 0.20)

Total nitrogen 3/3 3.8 1.3 (1.89, 1.90), (3.42, 3.36), (5.31, 5.60)

Nitrate plus nitrite 2/3 0.5 0.4 (1.75, 1.76), (5.44, 5.40)

Ammonia 0/3 0 0

Nitrite 0/3 0 0

66 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A4C. Quality-control summary for replicate analyses of trace elements detected in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[RSD, relative standard deviation in percent; nd, not detected; μg/L, micrograms per liter]

Constituent

Number of 

RSDs greater 

than zero/ 

number of 

replicates

Maximum 

RSD 

(percent)

Median 

RSD 

(percent)

Concentrations for 

replicates with 

RSD greater 

than zero 

(environmental/

replicate) 

(mg/L)

USGS National Water Quality Laboratory (Schedule 1948)

Aluminum 1/3 101 0 (nd, 3)

Antimony 0/3 0 0

Arsenic 1/3 4 0 (0.63, 0.67)

Barium 2/3 1.4 0.7 (49, 50), (109, 108)

Beryllium 0/3 0 0

Boron 2/3 3.1 1.8 (22, 23), (40, 39)

Cadmium 0/3 0 0

Chromium 0/3 0 0

Cobalt 3/3 3.5 1.5 (0.062, 0.059), (0.140, 0.137), (0.144, 0.147)

Copper 1/3 3.8 0 (1.9, 1.8)

Iron 1/3 8 0 (9, 8)

Lead 1/3 7 0 (2.03, 2.23)

Lithium 2/3 4.9 4.3 (1.7, 1.6), (1.5, 1.4)

Manganese 1/3 2 0 (3.2, 3.3)

Molybdenum 2/3 2 1.5 (4.9, 4.8), (27.1, 26.2)

Nickel 3/3 19 14 (0.36, 0.47), (2.74, 2.75), (1.94, 2.06)

Selenium 1/3 2 0 (0.37, 0.36)

Silver 0/3 0.0 0

Strontium 2/3 0 0.3 (220, 221), (158, 159)

Thallium 0/3 0 0

Tungsten 1/3 0.3 0 (22.0, 22.1)

Uranium 2/3 1.1 0.2 (1.31, 1.29), (4.47, 4.46)

Vanadium 3/3 1.0 0.6 (11.5, 11.4), (18.8, 18.7), (6.8, 6.7)

Zinc 3/3 23 8.3 (3.4, 4.7), (0.9, 0.8), (2.6, 2.8)

USGS Trace Metals Laboratory

Iron, total 1/2 101 51 (nd, 3)

Iron (II) 1/2 101 51 (nd, 3)

Arsenic, total 2/2 113 73 (2.6, 1.6), (nd, 1.1)

Arsenic (III) 0/2 0 0

Chromium, total 1/6 47 0 (2,1)

Chromium (VI) 0/6 0 0

Appendix Tables 67
Table A4D. Quality-control summary of replicate analyses of constituents of special interest and radioactive constituents detected 

in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[RSD, percent relative standard deviation; μg/L, microgram per liter; pCi/L, picocuries per liter]

Constituent

Number of 

RSDs greater 

than zero/

number of 

replicates

Maximum 

RSD 

(percent)

Median 

RSD 

(percent)

Concentrations for 

replicates with 

RSD greater 

than zero 

(environmental/

replicate)

Constituents of special interest (μg/L)

Perchlorate 2/5 19 0 (0.70, 0.92), (0.77,0.69)

1,2,3-Trichloropropane (1,2,3-TCP) 0/3 0 0

Radioactive constituents (pCi/L)

Radon-222 1/1 6.8 6.8 (286, 315)

Tritium 1/2 22 11 (1.9, 2.6)

68  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A5A. Quality-control summary for matrix-spike recoveries of volatile organic compounds (VOCs) and gasoline oxygenates 

and degradates in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006—Continued.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number of 

spike 

samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Acetone1 6 78 98 82

Acrylonitrile 6 97 115 106

tert-Amyl alcohol 2 95 113 104

Benzene 6 96 106 97

Bromobenzene 6 98 113 102

Bromochloromethane 6 82 96 88

Bromodichloromethane 6 104 132 109

Bromoethene 6 106 122 112

Bromoform (tribromomethane) 6 101 127 107

Bromomethane 6 86 147 124

2-Butanone (ethyl methyl ketone) 6 95 112 97

tert-Butyl alcohol (TBA) 2 88 110 99

Butylbenzene (n-Butylbenzene) 6 88 99 94

sec-Butylbenzene 6 94 106 100

tert-Butylbenzene 6 97 120 104

Carbon disulfide 6 87 101 95

Chlorobenzene 6 100 110 103

Chloroethane 6 80 97 88

Chloroform (trichloromethane)2 6 104 130 109

Chloromethane 6 81 113 94

3-Chloropropene 6 139 168 144

2-Chlorotoluene 6 96 109 99

4-Chlorotoluene 6 79 88 85

Dibromochloromethane 6 113 137 113

1,2-Dibromo-3-chloropropane (DBCP) 6 98 110 100

1,2-Dibromoethane (EDB) 6 100 115 104

Dibromomethane 6 96 121 102

1,2-Dichlorobenzene2 6 94 111 100

1,3-Dichlorobenzene 6 98 109 100

1,4-Dichlorobenzene 6 94 106 98

trans-1,4-Dichloro-2-butene 6 99 123 104

Dichlorodifluoromethane (CFC-12) 6 52 73 67

1,1-Dichloroethane 6 145 179 152

1,2-Dichloroethane 6 115 156 123

1,1-Dichloroethylene (DCE) 6 88 110 97

cis-1,2-Dichloroethylene2 6 100 115 103

trans-1,2-Dichloroethylene 6 96 111 99

Dichloromethane (methylene chloride) 6 24 30 30

1,1-Dichloropropene 6 131 155 138

1,2-Dichloropropane2 6 100 117 105

1,3-Dichloropropane 6 125 152 134

cis-1,3-Dichloropropene 6 97 110 102

trans-1,3-Dichloropropene 6 102 119 107

2,2-Dichloropropane 6 92 124 111

Diethyl ether 6 113 131 119

Diisopropyl ether1 6 96 115 102

Ethylbenzene 6 96 113 100

Ethyl tert-butyl ether (ETBE, tert-butyl ethyl ether)1 6 98 121 102

Ethyl methacrylate 6 102 117 102

o-Ethyl toluene (2-Ethyltoluene) 6 74 82 80

Hexachlorobutadiene 6 84 107 92

Hexachloroethane 6 101 117 103

Table A5A. Quality-control summary for matrix-spike recoveries of volatile organic compounds (VOCs) and gasoline oxygenates and 

degradates in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Appendix Tables 69
Table A5A. Quality-control summary for matrix-spike recoveries of volatile organic compounds (VOCs) and gasoline oxygenates 

and degradates in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, 

California, June 2006—Continued.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number of 

spike 

samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

2-Hexanone (n-Butyl methyl ketone) 6 97 111 101

Isopropylbezene 6 102 117 106

4-Isopropyl-1-methylbenzene 6 83 94 87

Methyl acetate 2 114 116 115

Methyl acrylate 6 105 120 108

Methyl acrylonitrile 6 84 99 90

Methyl tert-butyl ether (MTBE)1,2 6 94 120 99

Methyl iodide (iodomethane) 6 81 141 104

Methyl methacrylate 6 93 105 96

4-Methyl-2-pentanone (MIBK, isobutyl methyl ketone) 6 94 113 100

Methyl tert-pentyl ether1 6 119 144 122

Naphthalene 6 77 94 83

n-Propylbenzene 6 91 106 96

Styrene 6 94 102 100

1,1,1,2-Tetrachloroethane 6 100 119 102

1,1,2,2-Tetrachloroethane 6 114 127 116

Tetrachloroethene (PCE)2 6 96 108 99

Tetrachloromethane (carbon tetrachloride)2 6 164 221 188

Tetrahydrofuran 6 96 112 107

1,2,3,4-Tetramethylbenzene 6 63 77 68

1,2,3,5-Tetramethylbenzene (isodurene) 6 62 75 66

Toluene1 6 98 113 104

1,2,3-Trichlorobenzene 6 55 63 55

1,2,4-Trichlorobenzene 6 115 133 115

1,1,1-Trichloroethane (TCA) 6 104 136 111

1,1,2-Trichloroethane 6 84 102 87

Trichloroethene (TCE)2 6 94 115 100

Trichlorofluoromethane (CFC-11)2 6 106 149 119

1,2,3-Trichloropropane (1,2,3-TCP) 6 90 118 96

1,1,2-Trichlorotrifluoroethane (CFC-113)2 6 81 102 95

1,2,3-Trimethylbenzene 6 80 97 84

1,2,4-Trimethylbenzene 6 82 93 86

1,3,5-Trimethylbenzene 6 94 109 100

Vinyl chloride 6 87 106 87

m- and p-Xylene 6 166 189 172

o-Xylene 6 77 91 82

1

Constituents on schedules 2020 and 4024; only values from schedule 2020 are reported because it is the preferred analytical schedule.

2

Constituents detected in ground-water samples.

70 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A5B. Quality-control summary for matrix-spike recoveries of pesticides and pesticide degradates in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006—Continued.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number 

of spike 

 samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

 (percent)

Median 

recovery 

 (percent)

Acetochlor 5 82 108 100

Alachlor 5 89 110 102

Atrazine1 5 88 104 97

Azinphos-methyl 5 71 126 102

Azinphos-methyl-oxon 5 39 109 88

Benfluralin 5 47 77 69

Carbaryl 5 79 120 103

2-Chloro-2,6-diethylacetanilide 5 79 110 106

4-Chloro-2-methylphenol 5 55 71 58

Chlorpyrifos 5 87 97 89

Chlorpyrofos, oxygen analog 5 20 39 30

Cyfluthrin 5 49 75 51

Cypermethrin 5 47 70 53

Dacthal (DCPA) 5 87 108 102

Deethylatrazine (2-Chloro-4-isopropylamino-6-amino-s-triazine)1 5 38 53 51

Desulfinylfipronil 5 80 93 84

Desulfinylfipronil amide 5 53 112 78

Diazinon 5 86 102 90

Diazinon, oxon 5 49 99 90

3,4-Dichloroaniline 5 70 83 75

Dichlorvos 5 19 30 30

Dicrotophos 5 20 49 39

Dieldrin 5 71 121 96

2,6-Diethylaniline 5 88 97 94

Dimethoate 5 25 43 35

Ethion 5 65 119 90

Ethion monoxon 5 59 129 100

2-Ethyl-6-methylaniline 5 82 93 87

Fenamiphos 5 69 140 129

Fenamiphos sulfone 5 60 121 106

Fenamiphos sulfoxide 5 39 80 78

Fipronil 5 69 101 92

Fipronil sulfide1 5 75 93 87

Fipronil sulfone 5 57 94 64

Fonofos 5 82 96 88

Hexazinone 5 57 111 81

Isofenphos 5 85 108 103

Malaoxon 5 48 107 103

Malathion 5 80 107 104

Metalaxyl 5 85 106 97

Methidathion 5 83 133 105

Metolachlor 5 99 120 105

Metribuzin 5 65 89 86

Myclobutanil 5 77 112 94

1-Naphthol 5 19 59 20

Paraoxon-methyl 5 49 60 49

Parathion-methyl 5 60 92 84

Pendimethalin 5 76 112 108

cis-Permethrin 5 49 79 55

Phorate 5 69 101 73

Phorate oxon 5 69 120 117

Phosmet 2 8 8 8

Phosmet oxon 2 49 50 49

Table A5B. Quality-control summary for matrix-spike recoveries of pesticides and pesticide degradates in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Appendix Tables  71
Table A5B. Quality-control summary for matrix-spike recoveries of pesticides and pesticide degradates in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006—Continued.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number 

of spike 

 samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

 (percent)

Median 

recovery 

 (percent)

Prometon1 5 79 108 97

Prometryn 5 81 108 102

Propyzamide 5 77 104 98

Simazine1 5 81 103 99

Tebuthiuron 5 69 120 118

Terbufos 5 79 130 118

Terbufos oxon sulfone 5 49 119 98

Terbuthylazine 5 89 108 97

Trifluralin 5 55 85 78 1

Constituents detected in ground-water samples.

72 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A5C. Quality-control summary for matrix-spike recoveries of pharmaceutical 

compounds in samples collected for the Southern Sierra Groundwater Ambient 

Monitoring and Assessment (GAMA) study, California, June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number 

of spike 

samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

 (percent)

Median 

recovery 

(percent)

Acetaminophen 4 90 104 101

Caffeine 4 96 104 98

Carbamazapine1 4 70 96 93

Codeine 4 89 96 93

Cotinine 4 96 100 98

Dehydronifedipine 4 100 113 107

Diltiazem 4 44 59 50

1,7-Dimethylxanthine 4 89 98 93

Diphenhydramine1 4 55 74 69

Salbutamol (albuterol) 4 64 90 81

Sulfamethoxazole1 4 53 70 62

Thiabendazole 4 50 83 79

Trimethoprim 4 79 99 96

Warfarin 4 63 76 71

1

Constituents detected in ground-water samples.

Appendix Tables  73
Table A5D. Quality-control summary for matrix-spike recoveries of wastewater-indicator compounds in samples collected for the 

Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Constituent Recovery 

(percent) Constituent Recovery (percent)

Acetophenone 94 Menthol 98

Acetyl hexamethyl tetrahydro naphthalene 70 Metalaxyl 93

Anthracene, water 72 1-Methylnaphthalene 65

9,10-Anthraquinone 85 2-Methylnaphthalene 57

Benzo[a]pyrene 68 3-Methyl-1H-indole 83

Benzophenone 90 5-Methyl-1H-benzotriazole 51

Bisphenol A 19 Methyl salicylate 86

Bromacil 94 Metolachlor 84

3-tert-Butyl-4-hydroxyanisole 38 Naphthalene 73

Caffeine 87 4-Nonylphenol 65

Camphor 90 4-Nonylphenol diethoxylates 139

Carbaryl 80 4-Octylphenol 57

Carbazole 78 4-tert-Octylphenol 72

Chlorpyrifos 73 4-Octylphenol diethoxylates 89

Cholesterol 70 4-Octylphenol monoethoxylates 118

3-beta-Coprostanol 64 Pentachlorophenol 22

Cotinine 81 Phenanthrene 80

p-Cresol 80 Phenol 95

4-Cumylphenol, water 72 Prometon 83

DEET (N,N-diethyl-meta-toluamide) 89 Pyrene 76

Diazinon 80 beta-Sitosterol 53

1,4-Dichlorobenzene 60 beta-Stigmastanol 61

2,6-Dimethylnaphthalene 49 Tetrachloroethylene 15

Fluoranthene 77 Tribromomethane 69

Hexahydrohexamethyl cyclopentabenzopyran 75 Tributyl phosphate 86

Indole 76 Triclosan 74

Isoborneol 97 Triethyl citrate 90

Isophorone 92 Triphenyl phosphate 86

Isopropylbenzene 49 Tris(2-butoxyethyl) phosphate 92

Isoquinoline 86 Tris(2-chloroethyl) phosphate 83

D-Limonene 32 Tris(dichloroisopropyl) phosphate 89

74 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A5E. Quality-control summary for matrix-spike recoveries of N-Nitrosodimethylamine (NDMA) and 1,2,3-Trichloropropane 

(1,2,3-TCP) in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Constituent

Number of 

spike 

samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

1,2,3-Trichloropropane1 3 95 114 113

N-Nitrosdimethylamine (NDMA) 3 101 106 104

1

Constituent detected in ground-water samples

Appendix Tables  75
Table A6. Quality-control summary for surrogate recoveries of volatile organic compounds, gasoline oxygenates and degradates, 

pesticides and pesticide degradates, pharmaceutical compounds, wastewater-indicator compounds, and constituents of special 

interest in samples collected for the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) study, California, 

June 2006.

[MWH, Montgomery Watson-Harza Laboratory; VOC, volatile organic compound; 1,2,3-TCP, 1,2,3-trichloropropane; NDMA, N-nitrosodimethylamine; na, 

not analyzed]

Surrogate Analytical 

schedule

Constituent or 

constituent 

class 

analyzed

Number 

of blanks 

analyses

Median 

recovery 

 in blanks 

(percent)

Number of 

surrogate 

recoveries 

below 70 

percent 

in blanks

1-Bromo-4-fluorobenzene 2020, 4024 VOC, gas oxygenate 9 73 2

1,2-Dichloroethane-d4 2020, 4024 VOC, gas oxygenate 9 117 0

Isobutyl alcohol-d6 4024 Gas oxygenate 3 112 0

Toluene-d8 2020, 4024 VOC, gas oxygenate 9 99 0

Diazinon-d10 2003 Pesticide 5 98 0

alpha-HCH-d6 2003 Pesticide 5 87 0

Toluene-d8 MWH 1,2,3-TCP 3 100 0

NDMA-d6 MWH NDMA 3 64 0

Ethyl nicotinate-d4 2080 Pharmaceutical 10 107 0

Carbamazapine-d10 2080 Pharmaceutical 10 107 0

Caffeine-13C 1433 Wastewater-indicator na na na

Decafluorobiphenyl 1433 Wastewater-indicator na na na

Fluoranthene-d10 1433 Wastewater-indicator na na na

Surrogate

Number of 

surrogate 

recoveries 

above 130 

percent in 

blanks

Number of 

sample 

analyses

Median 

recovery in 

samples 

(percent)

Number of 

surrogate 

recoveries 

below 70 

percent 

in samples

Number of 

surrogate 

recoveries 

above 130 

percent 

in samples

1-Bromo-4-fluorobenzene 0 71 99 14 0

1,2-Dichloroethane-d4 1 71 115 0 10

Isobutyl alcohol-d6 0 30 109 0 1

Toluene-d8 0 71 100 0 0

Diazinon-d10 0 68 94 3 0

alpha-HCH-d6 0 68 94 7 0

Toluene-d8 0 27 99 0 0

NDMA-d6 0 27 91 4 0

Ethyl nicotinate-d4 0 62 102 0 0

Carbamazapine-d10 0 62 103 0 0

Caffeine-13C na 8 91 0 0

Decafluorobiphenyl na 8 45 8 0

Fluoranthene-d10 na 8 95 0 0

76 Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program
Table A7A. Quality-control summary for laboratory “set blanks” for pharmaceutical 

compounds corresponding to analyses of samples collected for the Southern Sierra 

Groundwater Ambient Monitoring and Assessment (GAMA) study, California, June 2006.

[μg/L, micrograms per liter; E, estimated value]

Constituent

Number of 

set blank 

detections/ 

analyses

Maximum 

concentration 

detected in 

set blank 

samples 

Minimum 

concentration 

detected in 

ground-water 

samples 

in set

Number of 

groundwater 

samples 

censored

Acetaminophen 0/11

Albuterol 0/11

Caffeine 0/11

Carbamazapine 1/11 E0.0006 E0.004 0

Codeine 0/11

Cotinine 0/11

Dehydronifedipine 0/11

Diltiazem 0/11

1,7-Dimethylxanthine 0/11

Diphenhydramine 1/11 E0.0005 E0.004 0

Sulfamethoxazole 0/11

Thiabendazole 0/11

Trimethoprim 0/11

Warfarin 0/11

Appendix Tables  77
Table A7B. Quality-control summary for laboratory “set spikes” for 

pharmaceutical compounds corresponding to analyses of samples collected for 

the Southern Sierra Groundwater Ambient Monitoring and Assessment (GAMA) 

study, California, June 2006.

[Acceptable recovery range is between 70 and 130 percent]

Constituent 

Number of 

set spike 

samples

Minimum 

recovery 

(percent)

Maximum 

recovery 

(percent)

Median 

recovery 

(percent)

Acetaminophen 11 60 92 69

Albuterol 11 69 98 82

Caffeine 11 90 104 94

Carbamazapine1 11 84 93 88

Codeine 11 76 84 81

Cotinine 11 94 102 97

Dehydronifedipine 11 69 93 86

Diltiazem 11 4 47 21

1,7-dimethylxanthine 11 56 88 78

Diphenhydramine1 11 57 70 60

Sulfamethoxazole1 11 58 78 70

Thiabendazole 11 70 89 87

Trimethoprim 11 88 96 92

Warfarin 11 18 65 35

1

Constituents detected in ground-water samples.

78  Ground-Water Quality Data in the Southern Sierra Study Unit, 2006—Results from the California GAMA Program

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