USGS 20 (433253112545901)

1985 1990 1995 2000 2005 2010

0

5,000

15,000

25,000

Regression, p < 0.001

Tritium, in picocuries per liter

USGS 87 (433013113024201)

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

0.0

0.5

1.0

1.5

2.0

Regression, p < 0.001

Trichloroethene, in micrograms per liter

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2015–5003

DOE/ID-22233

Prepared in cooperation with the U.S. Department of Energy

Water-Quality Characteristics and Trends for Selected 

Wells Possibly Influenced by Wastewater Disposal at the 

Idaho National Laboratory, Idaho, 1981–2012 
Cover: Graphical presentations showing decreasing trending interval censored tritium 

data from well USGS 20 and increasing trending left censored trichloroethene data 

from well USGS 87.
Water-Quality Characteristics and Trends for 

Selected Wells Possibly Influenced by Wastewater 

Disposal at the Idaho National Laboratory, Idaho, 

1981–2012

By Linda C. Davis, Roy C. Bartholomay, Jason C. Fisher, and Neil V. Maimer

DOE/ID-22233

Prepared in cooperation with the U.S. Department of Energy

Scientific Investigations Report 2015–5003

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director 

U.S. Geological Survey, Reston, Virginia: 2015

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

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Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Davis, L.C., Bartholomay, R.C., Fisher, J.C., and Maimer, N.V., 2015, Water-quality characteristics and trends for 

selected wells possibly influenced by wastewater disposal at the Idaho National Laboratory, Idaho, 1981–2012: U.S. 

Geological Survey Scientific Investigations Report 2015–5003 (DOE/ID-22233), 106 p., http://dx.doi.org/10.3133/

sir20155003.

ISSN 2328-0328 (online)
iii

Contents

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

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

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

Geohydrologic Setting .........................................................................................................................2

Previous Investigations........................................................................................................................4

Methods...........................................................................................................................................................7

Sample Collection and Analyses........................................................................................................7

Quality Assurance/Quality Control ..................................................................................................11

Guidelines for Interpretation of Analytical Results ......................................................................11

Statistical Data Analysis Methods...................................................................................................14

Water-Quality Characteristics and Trends ..............................................................................................16

pH, Specific Conductance, and Temperature................................................................................16

Tritium ..................................................................................................................................................20

Strontium-90.........................................................................................................................................20

Cesium-137...........................................................................................................................................20

Plutonium..............................................................................................................................................20

Americium-241.....................................................................................................................................30

Gross Alpha- and Beta-Particle Radioactivity...............................................................................30

Chloride.................................................................................................................................................30

Sodium..................................................................................................................................................36

Fluoride.................................................................................................................................................36

Sulfate ..................................................................................................................................................36

Nitrite Plus Nitrate (as N) ..................................................................................................................40

Orthophosphate (as P) .......................................................................................................................40

Trace Elements....................................................................................................................................40

Chromium .............................................................................................................................................46

Total Organic Carbon..........................................................................................................................46

Volatile Organic Compounds.............................................................................................................46

Factors Influencing Water-Quality Trends at Each Well ......................................................................47

Aquifer Wells near Idaho Nuclear Technology and Engineering Center..................................47

Aquifer Wells near Advanced Test Reactor Complex ..................................................................50

Aquifer Wells near Central Facilities Area .....................................................................................50

Aquifer Wells near Radioactive Waste Management Complex .................................................51

Aquifer Wells South of Facilities ......................................................................................................52

Perched Groundwater Wells near Idaho Nuclear Technology and Engineering Center .......52

Perched Groundwater Wells near Advanced Test Reactor Complex........................................52

Perched Groundwater Well at Radioactive Waste Management Complex .............................54

Summary and Conclusions.........................................................................................................................55

References Cited..........................................................................................................................................56
iv

Appendixes .................................................................................................................................................105

Appendix A. Package ‘Trends’ and Processing Instructions for the 2014 Trend Analysis..105

Appendix B. Plots of Trend Analyses for pH, Specific Conductance, and Water 

Temperature from Selected Sites, 1989–2012.................................................................105

Appendix C. Plots of Trend Analyses for Selected Radiochemical Constituents from 

Selected Sites, 1981–2012..................................................................................................105

Appendix D. Plots of Trend Analyses for Selected Constituents from Selected Sites, 

1989–2012..............................................................................................................................105

Appendix E. Plots of Trend Analyses for Volatile Organic Compounds from Selected Sites, 

1987–2012..............................................................................................................................105

Contents—Continued

Figures

1. Map showing locations of selected facilities at the Idaho National Laboratory, 

Idaho ...............................................................................................................................................3

2. Map showing locations of wells in the eastern Snake River Plain aquifer at and

near the Idaho National Laboratory, Idaho ..............................................................................8

3. Map showing locations of wells in the eastern Snake River Plain aquifer at and

near the Advanced Test Reactor Complex, the Idaho Nuclear Technology and

Engineering Center, and the Radioactive Waste Management Complex, Idaho

National Laboratory, Idaho..........................................................................................................9

4. Map showing locations of perched groundwater wells at and near the Advanced

Test Reactor Complex, the Idaho Nuclear Technology and Engineering Center, and

the Radioactive Waste Management Complex, Idaho National Laboratory, Idaho........10

5. Map showing areal distribution of specific conductance trends in water from

selected aquifer wells at and near the Idaho National Laboratory, Idaho .......................17

6. Map showing areal distribution of specific conductance trends in water from

selected aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................18

7. Map showing areal distribution of specific conductance trends in water from

selected perched groundwater wells at the Advanced Test Reactor Complex, 

Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste

Management Complex, the Idaho National Laboratory, Idaho...........................................19

8. Map showing areal distribution of temperature trends in water from selected

aquifer wells at and near the Idaho National Laboratory, Idaho........................................21

9. Map showing areal distribution of temperature trends in water from selected

aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear Technology

and Engineering Center, and the Radioactive Waste Management Complex, Idaho

National Laboratory, Idaho........................................................................................................22

10. Map showing areal distribution of temperature trends in water from selected

perched groundwater wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................23
v

Figures—Continued

11. Map showing areal distribution of tritium trends in water from selected aquifer

wells at and near the Idaho National Laboratory, Idaho......................................................24

12. Map showing areal distribution of tritium trends in water from selected aquifer

wells at the Advanced Test Reactor Complex, Idaho Nuclear Technology and

Engineering Center, and the Radioactive Waste Management Complex, Idaho

National Laboratory, Idaho........................................................................................................25

13. Map showing areal distribution of tritium trends in water from selected perched

groundwater wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................26

14. Map showing areal distribution of strontium-90 trends in water from selected

aquifer wells at and near the Idaho National Laboratory, Idaho........................................27

15. Map showing areal distribution of strontium-90 trends in water from selected

aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear Technology

and Engineering Center, and the Radioactive Waste Management Complex, Idaho

National Laboratory, Idaho........................................................................................................28

16. Map showing areal distribution of strontium-90 trends in water from selected

perched groundwater wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................29

17. Map showing areal distribution of chloride concentration trends in water from

selected aquifer wells at and near the Idaho National Laboratory, Idaho .......................31

18. Map showing areal distribution of chloride concentration trends in water from

selected aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................32

19. Map showing areal distribution of chloride concentration trends in water from

selected perched groundwater wells at the Advanced Test Reactor Complex, Idaho

Nuclear Technology and Engineering Center, and the Radioactive Waste

Management Complex, Idaho National Laboratory, Idaho..................................................33

20. Graphs showing fluctuations in chloride, sodium, and sulfate concentrations

relative to water-level changes at wells USGS 35 and USGS 39 and changes in

streamflow from the Big Lost River, Idaho .............................................................................34

21. Map showing areal distribution of sodium concentration trends in water from

selected aquifer wells at and near the Idaho National Laboratory, Idaho .......................37

22. Map showing areal distribution of sodium concentration trends in water from

selected aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................38

23. Map showing areal distribution of sodium concentration trends in water from

selected perched groundwater wells at the Advanced Test Reactor Complex, 

Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste

Management Complex, Idaho National Laboratory, Idaho..................................................39

24. Map showing areal distribution of sulfate concentration trends in water from

selected wells at and near the Idaho National Laboratory, Idaho.....................................41
vi

Figures—Continued

25. Map showing areal distribution of sulfate concentration trends in water from

selected aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear

Technology and Engineering Center, and the Radioactive Waste Management

Complex, Idaho National Laboratory, Idaho...........................................................................42

26. Map showing areal distribution of sulfate concentration trends in water from

selected perched groundwater wells at the Advanced Test Reactor Complex, 

Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste

Management Complex, Idaho National Laboratory, Idaho..................................................43

27. Map showing areal distribution of nitrite plus nitrate (as N) concentration trends in

water from selected wells at and near the Idaho National Laboratory, Idaho ................44

28. Map showing areal distribution of nitrite plus nitrate (as N) concentration trends in

water from selected aquifer wells at the Advanced Test Reactor Complex, Idaho

Nuclear Technology and Engineering Center, and the Radioactive Waste

Management Complex, Idaho National Laboratory, Idaho..................................................45

29. Graph showing carbon tetrachloride trend from Radioactive Waste Management

Complex Production well, Idaho National Laboratory, Idaho, 2005–12 .............................47

Tables

1. Summary of selected previous investigations on geology, hydrology, and

characteristics of groundwater and perched groundwater at and near the Idaho

National Laboratory, Idaho, 1961–2013 .....................................................................................5

2. Site information for wells at and near the Idaho National Laboratory, Idaho..................12

3. Comparison of trend analyses for selected wells using additional explanatory

variables, included as covariates to the trend model, Idaho National Laboratory,

Idaho .............................................................................................................................................15

4. Summary statistics and trend analyses for field measurements of pH, specific

conductance, and water temperature for aquifer and perched groundwater wells

after installation of dedicated pumps at and near the Idaho National Laboratory,

Idaho, 1989–2012.........................................................................................................................63

5. Summary statistics and trend test results for selected radiochemical constituents

in water from aquifer and perched groundwater wells at and near the Idaho

National Laboratory, Idaho, 1981–2012 ...................................................................................73

6. Summary of water-quality results for selected radiochemical constituents in water

from aquifer and perched groundwater wells at and near the Idaho National

Laboratory, Idaho........................................................................................................................79

7. Summary statistics and trend test results for selected constituents in water from

aquifer and perched groundwater wells at and near the Idaho National Laboratory,

Idaho, 1989–2012.........................................................................................................................87

8. Summary statistics and trend test results for volatile organic compounds in water 

from aquifer wells at and near the Idaho National Laboratory, Idaho, 1987–2012 ........103
vii

Conversion Factors, Datums, and Abbreviations

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

Flow rate

acre-foot per year (acre-ft/yr) 1,233 cubic meter per year (m3

/yr)

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Transmissivity*

foot squared per day (ft2

/d) 0.09290 meter squared per day (m2/d)

SI to Inch/Pound

Multiply By To obtain

Volume

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

Mass

kilogram (kg) 2.205 pound avoirdupois (lb)

Radioactivity

picocurie per liter (pCi/L) 0.037 Becquerel per liter Bq/L

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

°F=(1.8×°C)+32.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times 

foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot 

squared per day (ft2/d), is used for convenience.

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

25 °C).

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

or micrograms per liter (μg/L).
viii

Conversion Factors, Datums, and Abbreviations—Continued

Datums

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29).

Horizontal coordinate information is referenced to the North American Datum of 1927 (NAD 27).

Altitude, as used in this report, refers to distance above the vertical datum.

Abbreviations

AFT accelerated failure time

ATR Complex Advanced Test Reactor Complex (formerly RTC, Reactor Technology 

Complex, and TRA, Test Reactor Area)

BLS below land surface

CFA Central Facilities Area

CFC chlorofluorocarbon

CRAN Comprehensive R Active Network

DOE U.S. Department of Energy

ESRP eastern Snake River Plain

E-value estimated value

INEL Idaho National Engineering Laboratory (1974–97)

INL Idaho National Laboratory

INTEC Idaho Nuclear Technology and Engineering Center

IRL interim reporting level

LRL laboratory reporting level

LT-MDL long-term method detection level

MCL maximum contaminant level

MLE maximum-likelihood estimation

NRF Naval Reactors Facility

NWIS National Water Information System

NWQL National Water Quality Laboratory (USGS)

PBF Power Burst Facility

RESL Radiological and Environmental Sciences Laboratory (DOE)

QA quality assurance

QC quality control

RWMC Radioactive Waste Management Complex

s sample standard deviation

SDA Subsurface Disposal Area

TAN Test Area North

TOC total organic carbon

USGS U.S. Geological Survey

VOC volatile organic compound
Water-Quality Characteristics and Trends for Selected 

Wells Possibly Influenced by Wastewater Disposal at the 

Idaho National Laboratory, Idaho, 1981–2012

By Linda C. Davis, Roy C. Bartholomay, Jason C. Fisher, and Neil V. Maimer

Abstract

The U.S. Geological Survey, in cooperation with the 

U.S. Department of Energy, analyzed water-quality data 

collected from 64 aquifer wells and 35 perched groundwater 

wells at the Idaho National Laboratory (INL) from 1981 

through 2012. The wells selected for the study were wells that 

possibly were affected by wastewater disposal at the INL. The 

data analyzed included tritium, strontium-90, major cations, 

anions, nutrients, trace elements, total organic carbon, and 

volatile organic compounds. The analyses were performed 

to examine water-quality trends that might influence future 

management decisions about the number of wells to sample at 

the INL and the type of constituents to monitor.

The data were processed using custom computer scripts 

developed in the R programming language. Summary statistics 

were calculated for the datasets. Water-quality trends were 

determined using a parametric survival regression model to fit 

the observed data, including left-censored, interval-censored, 

and uncensored data. The null hypothesis of the trend test 

was that no relation existed between time and concentration; 

the alternate hypothesis was that time and concentration 

were related through the regression equation. A significance 

level of 0.05 was selected to determine if the trend was 

statistically significant.

Trend test results for tritium and strontium-90 

concentrations in aquifer wells indicated that nearly all wells 

had decreasing or no trends. Similarly, trends in perched 

groundwater wells were mostly decreasing or no trends; trends 

were increasing in two perched groundwater wells near the 

Advanced Test Reactor Complex. Decreasing trends generally 

are attributed to lack of recent wastewater disposal and 

radioactive decay.

Trend test results for chloride, sodium, sulfate, nitrite 

plus nitrate (as nitrogen), chromium, trace elements, and total 

organic carbon concentrations in aquifer wells indicated that 

most wells had either decreasing or no trends. The decreasing 

trends in these constituents are attributed to decrease in 

disposal of these constituents, as well as discontinued use 

of the old percolation ponds south of the Idaho Nuclear 

Technology and Engineering Center (INTEC) and redirection 

of wastewater to the new percolation ponds 2 miles southwest 

of the INTEC in 2002.

Chloride (along with sodium, sulfate, and some nitrate) 

concentrations in wells south of the INTEC may be influenced 

by episodic recharge from the Big Lost River. These 

constituent concentrations decrease during wetter periods 

when there is probably more recharge from the Big Lost River 

and increase during dry periods, when there is less recharge.

Some wells downgradient of the Central Facilities Area 

and near the southern boundary of the INL showed increasing 

trends in sodium concentration, whereas there was no trend in 

chloride. The increasing trend for sodium could be due to the 

long term influence of wastewater disposal from upgradient 

facilities and the lack of trend for chloride could be because 

chloride is more mobile than sodium and more dispersed in 

the aquifer system. 

Volatile organic compound concentration trends were 

analyzed for nine aquifer wells. Trend test results indicated an 

increasing trend for carbon tetrachloride for the Radioactive 

Waste Management Complex Production Well for the period 

1987–2012; however, trend analyses of data collected since 

2005 show no statistically significant trend indicating that 

engineering practices designed to reduce movement of volatile 

organic compounds to the aquifer may be having a positive 

effect on the aquifer.

Introduction

The Idaho National Laboratory (INL), operated by 

the U.S. Department of Energy (DOE), encompasses 

about 890 mi2 of the eastern Snake River Plain (ESRP) in 

southeastern Idaho (fig. 1). The INL was established in 1949 

to develop atomic energy, nuclear safety research, defense 

programs, environmental research, and advanced energy 

concepts. Wastewater disposal sites at the Test Area North 

(TAN), the Naval Reactors Facility (NRF), the Advanced Test 

Reactor Complex (ATR Complex), and the Idaho Nuclear 

Technology and Engineering Center (INTEC) (fig. 1) have 
2 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

contributed radioactive- and chemical-waste contaminants to 

the ESRP aquifer. These sites incorporated various wastewater 

disposal methods, including lined evaporation ponds, unlined 

percolation (infiltration) ponds and ditches, drain fields, and 

injection wells. Waste materials buried in shallow pits and 

trenches within the Subsurface Disposal Area (SDA) at the 

Radioactive Waste Management Complex (RWMC) also have 

contributed contaminants to groundwater. 

Since 1949, the U.S. Geological Survey (USGS) 

has worked in cooperation with the DOE at the INL to 

define: (1) the quality and availability of water for human 

consumption, (2) the usability of the water for supporting 

construction and cooling of facilities and for diluting 

concentrated waste streams, (3) the location and movement of 

contaminants in the ESRP aquifer and perched groundwater 

zones, (4) the sources of recharge to the aquifer, (5) an early 

detection network for contaminants moving past the INL 

boundaries, and (6) the processes controlling the origin 

and distribution of contaminants and naturally occurring 

constituents in the aquifer (Ackerman and others, 2010).

Since its inception, this water-quality monitoring program 

at the INL has included a network that once numbered as 

many as 200 wells. The network of wells has been sampled 

over the years for tritium, strontium-90, iodine-129, 

cesium-137, plutonium-238, plutonium-239, -240 (undivided), 

americium-241, gross alpha- and gross beta-radioactivity, 

sodium, bromide, chloride, fluoride, sulfate, nitrate, chromium 

and other trace elements, volatile organic compounds (VOCs), 

and total organic carbon (TOC) (Bartholomay, 2013; Davis 

and others 2013). Most wells in this network were constructed 

as open boreholes, and many are open to the aquifer 

throughout their entire depth below the water table. 

Purpose and Scope

This report presents an analysis of water-quality 

characteristics and trends for groundwater samples collected 

from selected wells that possibly are affected by wastewater 

disposal at and near the INL. Water-quality trends were 

examined to aid future management decisions regarding 

the number of wells to sample at the INL and the type of 

constituents to monitor. The criteria for selecting the sampling 

sites analyzed in this report were: (1) that at least 10 years 

of data were available for each site, and (2) that the sites 

represented water in a location that probably was affected by 

INL wastewater disposal. 

Water samples collected from 64 aquifer wells and 

35 perched groundwater wells were analyzed for selected 

constituents. The constituents include some combination 

of tritium, strontium-90, cesium-137, plutonium-238, 

plutonium-239, -240 (undivided), americium-241, gross 

alpha- and beta-particle radioactivity, calcium, magnesium, 

potassium, silica, sodium, bromide, chloride, fluoride, sulfate, 

nitrate (as N), orthophosphate (as P), chromium and other 

trace elements, and TOC. Constituent concentrations were 

plotted against time to evaluate the data; additional trend 

analyses were completed using the R programming language 

“Trends” package (Fisher and Davis, 2014; appendix A), 

which incorporates a parametric survival regression model 

that is fit to the observed data, including left-censored (values 

reported as less than a laboratory reporting level [LRL]), 

interval-censored (values with an associated uncertainty), and 

uncensored data. Summary statistics were also calculated for 

the datasets. 

Geohydrologic Setting

The INL is located on the west-central part of the ESRP. 

The ESRP is a northeast-trending structural basin about 

200 mi long and 50–70 mi wide (fig. 1). The basin has been 

filled with basaltic lava flows interbedded with terrestrial 

sediments. The basaltic rocks and sedimentary deposits 

combine to form the ESRP aquifer, which is the primary 

source of groundwater for the ESRP. 

The ESRP aquifer is one of the most productive aquifers 

in the United States (U.S. Geological Survey, 1985, p. 193). 

Groundwater generally moves from northeast to southwest and 

discharges to springs along the Snake River downstream of 

Twin Falls, Idaho, about 100 mi southwest of the INL (fig. 1). 

Groundwater moves horizontally through basalt interflow 

zones and vertically through joints and interfingering edges 

of basalt flows. Infiltration of surface water, heavy pumpage, 

geohydrologic conditions, and seasonal fluxes of recharge 

and discharge locally affect the movement of groundwater 

(Garabedian, 1986). The ESRP aquifer is recharged primarily 

from infiltration of applied irrigation water, infiltration of 

streamflow, groundwater inflow from adjoining mountain 

drainage basins, and infiltration of precipitation (Ackerman 

and others, 2006). 

At the INL, depth to water in wells completed in 

the ESRP aquifer ranges from about 200 ft below land 

surface in the northern part of the INL to more than 900 ft 

below land surface in the southeastern part of the INL. A 

significant proportion of the groundwater moves through 

the upper 200–800 ft of basaltic rock (Mann, 1986, p. 21). 

Ackerman (1991a, p. 30) and Bartholomay and others (1997, 

table 3) reported transmissivity values for basalt in the upper 

part of the aquifer ranging from 1.1 to 760,000 ft2/d. The 

hydraulic gradient at the INL ranges from 2 to 10 ft/mi, 

with an average of 4 ft/mi (Davis and others, 2013, fig. 9). 

Horizontal flow velocities of 2 to 26 ft/d have been calculated 

based on the movement of various constituents in different 

areas of the aquifer at and near the INL (Robertson and others, 

1974; Mann and Beasley, 1994; Cecil and others, 2000; 

Plummer and others, 2000; and Busenberg and others, 2001). 
Introduction 3

tac14-0956_fig01

Mud

Lake

Big

Lost

River

Little

Lost

River

Birch

Creek

Mackay

Reservoir

Camas

Creek

26

93

20

26

33

22

28

20

93

Big 

Southern

Butte

East

Butte

Middle Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

PIONEER MOUNTAINS

WHITE KNOB

MOUNTAINS

Atomic

City

Howe

Arco

Mud

Lake

Terreton

Mackay

TAN

ATR

Complex

INTEC

CFA

NRF

RWMC

MFC

PBF

Big Lost River

playas and sinks

Birch Creek

sinks

SPREADING

AREAS

13132535

Big Lost River at

Lincoln Blvd Bridge 

near Atomic City, ID

13132520

Big Lost River below INL 

diversion near Arco, ID

13132513

INL diversion at head near Arco, ID

13127000

Big Lost River below 

Mackay Reservoir, 

near Mackay, ID

113°00’ 45’

44°

00’

45’

43°

30’

113°30’ 15’ 30’ 112°15’

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0 10

10

20 KILOMETERS

20 MILES

20

26

13132513

MFC

CFA

INTEC

NRF

RWMC

TAN

ATR Complex

PBF

Selected facilities at the Idaho National Laboratory

 Materials and Fuels Complex 

 Central Facilities Area

 Idaho Nuclear Technology and Engineering Center

 Naval Reactors Facility

 Power Burst Facility

 Radioactive Waste Management Complex

 Advanced Test Reactor Complex—formerly known as

 Reactor Technology Complex (RTC) and Test Reactor

 Area (TRA)

 Test Area North

Boundary of Idaho National Laboratory

U.S. Geological Survey streamgage and No.

EXPLANATION

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls Pocatello

Idaho

Falls

Snake 

River

IDAHO

NATIONAL 

LABORATORY

BOUNDARY

Figure 1. Locations of selected facilities at the Idaho National Laboratory, Idaho.
4 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

These flow rates equate to a travel time of about 50–700 years 

for water beneath the INL to travel to springs that discharge 

at the terminus of the ESRP groundwater- flow system near 

Twin Falls, Idaho. Localized tracer tests at the INL have 

shown that vertical- and horizontal-transport rates are as 

high as 60–150 ft/d (Nimmo and others, 2002; Duke and 

others, 2007).

Olmsted (1962), Robertson and others (1974), and 

Busenberg and others (2001) classified groundwater at the INL 

based on chemical types derived from dissolution of the rocks 

and minerals within the recharge source areas. Olmsted’s type 

A water consisted of calcium and magnesium concentrations 

that constituted at least 85 percent of the cations and 

bicarbonate that constituted at least 70 percent of the anions. 

Type A water is present in the central and western part of the 

INL. Type A water is attributed to seepage loss from the Big 

Lost River and from groundwater underflow from the Big 

Lost River, Little Lost River, and Birch Creek drainage basins 

to the west and northwest of the INL (fig. 1) that contain 

alluvium derived from Paleozoic carbonate rocks from the 

surrounding mountains. 

Olmsted’s type B water, which is characterized by 

higher equivalent fractions of sodium, potassium, fluoride, 

and silica than type A water, underlies much of the eastern 

part of the INL and is often referred to as regional water. The 

groundwater originates from the area northeast of the INL 

that is composed of a much higher fraction of rhyolitic and 

andesitic volcanic rocks than mountains west and northwest of 

the INL that contribute to Type A water. Busenberg and others 

(2001) used age dating techniques of chlorofluorocarbons 

(CFCs), sulfur hexafluoride, and tritium/helium to further 

classify the regional water at the INL into two types based 

on the recharge type of the young fraction of groundwater. 

Water in the southeastern part of the INL represented a 

binary mixture of old (water greater than 40 to 55 years old 

that did not contain tritium or CFCs, respectively) regional 

groundwater underflow with young water derived from rapid, 

focused recharge, probably from precipitation infiltration. 

Water in the northeastern part of the INL is old, regional 

groundwater underflow that is mixed with local rapid, focused 

recharge; slow, diffuse areal recharge through the unsaturated 

zone; and agricultural return flow from the Mud Lake and 

Terreton areas (fig. 1). 

 Disposal of wastewater to infiltration ponds and 

infiltration of surface water at waste-burial sites at the INL 

has resulted in the formation of perched groundwater in 

basalts and in sedimentary interbeds that overlie the ESRP 

aquifer (Cecil and others, 1991). Perched groundwater has 

formed in a complex sequence of basalt flow and sedimentary 

interbeds beneath the ATR Complex, the INTEC, and the 

RWMC. Perched groundwater also has been detected beneath 

infiltration ponds and ditches at other facilities at the INL in 

the past, but is not discussed in this report. 

Anderson and Lewis (1989) and Anderson (1991) 

correlated geophysical logs to describe the stratigraphic 

sequences in which perched groundwater has formed at 

the ATR Complex, INTEC, and the RWMC. Although the 

subsurface stratigraphy, geohydrologic characteristics, and 

waste disposal practices at each of these areas differs, the 

features controlling the formation of perched groundwater at 

these sites are similar (Cecil and others, 1991). Sedimentary 

interbeds in the subsurface may have smaller vertical 

hydraulic conductivities than overlying basalt flows, and 

alteration between basalt flows may contribute to reduced 

vertical hydraulic conductivity in the interflow rubble zones 

(Perkins and Winfield, 2007). Dense, unfractured basalt 

flows may have a decreased vertical hydraulic conductivity 

and inhibited downward flow, and sedimentary or chemical 

infilling of fractures in basalt may decrease vertical hydraulic 

conductivity by limiting the interconnectivity of fractures 

that reduce the water transmitting capability of the basalts 

(Cecil and others, 1991). Any combination of these factors 

may disrupt the downward vertical movement of water and 

contribute to the formation of perched groundwater zones.

At the ATR Complex, deep and shallow perched 

groundwater zones have formed as a result of disposal of 

wastewater to infiltration ponds (Tucker and Orr, 1998). South 

of the INTEC, perched groundwater zones formed previously 

because of wastewater disposal to the old percolation ponds, 

but the zones have dried up since the ponds were taken out of 

service in 2002. Perched groundwater also has been detected 

in other areas at the INTEC and may be attributed to leaking 

pipelines, leach fields, damaged casing in the upper part of the 

INTEC disposal well, other infiltration ponds, or landscape 

irrigation (Tucker and Orr, 1998). Perched groundwater also 

is present below the new percolation ponds that were put 

into service during 2002. Perched groundwater beneath the 

RWMC formed from infiltration of snowmelt and rain and 

recharge from the Big Lost River and INL spreading areas. 

This perched groundwater contains constituents leached from 

buried radioactive and organic-chemical wastes. Perched 

groundwater beneath wastewater infiltration ponds and buried 

waste is an integral part of the pathway for waste-constituent 

migration to the ESRP aquifer. The extent of perched 

groundwater is affected by the waste-disposal practices.

Previous Investigations

Hydrologic conditions and the distribution of selected 

wastewater constituents in groundwater and perched 

groundwater are discussed in a series of reports describing 

the INL. Table 1 summarizes selected previous investigations 

of the geology, hydrology, and characteristics of groundwater 

and perched water at and near the INL, specifies the periods 

covered by some of those investigations, and lists report 

citations. Full references for these citations are available in the 

section, “References Cited.” Numerous previous investigations 

on the hydrology and geology at the INL have been done by 

INL contractors, state agencies, and the USGS. The USGS 

provides a list of references and hyperlinks to published 

reports from its previous INL studies at the USGS INL Project 

Office Web site at http://id.water.usgs.gov/projects/INL/index.

html.
Introduction 5

Table 1. Summary of selected previous investigations on geology, hydrology, and characteristics of groundwater and perched 

groundwater at and near the Idaho National Laboratory, Idaho, 1961–2013.

[Abbreviations: NRTS, National Reactor Testing Station; RWMC, Radioactive Waste Management Complex; INEL, Idaho National Engineering Laboratory; 

INEEL, Idaho National Engineering and Environmental Laboratory; INL, Idaho National Laboratory; ATR Complex, Advanced Test Reactor Complex (formerly 

the TRA, Test Reactor Area and the RTC, Reactor Technology Complex); INTEC, Idaho Nuclear Technology and Engineering Center (formerly the ICPP, Idaho 

Chemical Processing Plant); NA, not applicable]

Reference Investigation 

period Summary

Groundwater

Olmsted (1962) NA Chemical and physical character of groundwater at the NRTS, Idaho

Morris and others (1963, 1964, 1965) NA Hydrology of waste disposal at the NRTS, Idaho

Barraclough and others (1967a) 1965 Hydrology of the NRTS, Idaho

Barraclough and others (1967b) 1966 Hydrology of the NRTS, Idaho

Nace and others (1975) NA Generalized geologic framework of the NRTS, Idaho

Robertson and others (1974) NA Effects of waste disposal on the geochemistry of groundwater at the

NRTS, Idaho

Barraclough and others (1976) NA Hydrology of the solid waste burial ground (now the RWMC)

Barracough and Jenson (1976) 1971–73 Hydrologic data for the Idaho INEL, Idaho

Barraclough and others (1981) 1974–78 Hydrologic conditions for the INEL, Idaho

Lewis and Jensen (1985) 1979–81 Hydrologic conditions for the INEL, Idaho

Pittman and others (1988)

http://pubs.er.usgs.gov/publication/wri894008

1982–85 Hydrologic conditions for the INEL, Idaho

Orr and Cecil (1991)

http://pubs.er.usgs.gov/publication/wri914047

1986–88 Hydrologic conditions and distribution of selected chemical constituents in 

water at the INEL, Idaho

Ackerman (1991a) NA Analyzed data from 183 aquifer tests conducted in 94 wells to estimate 

transmissivity of basalts and sedimentary interbeds containing 

groundwater beneath the INL

Bartholomay and others (1995) 1989–91 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in water, INEL, Idaho

Bartholomay and others (1997)

http://pubs.er.usgs.gov/publication/wri974086

1992–95 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in water, INEL, Idaho

Bartholomay and others (2000)

http://pubs.er.usgs.gov/publication/wri004192

1996–98 Hydrologic conditions and distribution of selected constituents in water, 

INEEL, Idaho

Davis (2006b) 

http://pubs.er.usgs.gov/publication/sir20065088

1999–2001 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in water, INL, Idaho

Ackerman and others (2006)

http://pubs.er.usgs.gov/publication/sir20065122

NA Conceptual model of groundwater flow in the eastern Snake River Plain 

aquifer, INL, with implications for contaminant transport

Davis (2008)

http://pubs.er.usgs.gov/publication/sir20085089

2002–05 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho

Davis (2010)

http://pubs.er.usgs.gov/publication/sir20105197

2006–08 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho.

Ackerman and others (2010) NA Steady-state and transient models of groundwater flow and advective 

transport in the eastern Snake River Plain aquifer at the INL.

Bartholomay and others (2012)

http://pubs.er.usgs.gov/publication/sir20125169

1949–2009 Water-quality characteristics and trends for selected sites at and near the 

INL, Idaho

Fisher and others (2012) NA Comparison of 3-dimensional model estimates of groundwater source 

areas and velocities to independently derived estimates at INL

Davis and others (2013) 2009–11 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho
6 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 1. Summary of selected previous investigations on geology, hydrology, and characteristics of groundwater and perched 

groundwater at and near the Idaho National Laboratory, Idaho, 1961–2013.—Continued

[Abbreviations: NRTS, National Reactor Testing Station; RWMC, Radioactive Waste Management Complex; INEL, Idaho National Engineering Laboratory; 

INEEL, Idaho National Engineering and Environmental Laboratory; INL, Idaho National Laboratory; ATR Complex, Advanced Test Reactor Complex (formerly 

the TRA, Test Reactor Area and the RTC, Reactor Technology Complex); INTEC, Idaho Nuclear Technology and Engineering Center (formerly the ICPP, Idaho 

Chemical Processing Plant); na, not applicable]

Reference Investigation 

period Summary

Perched groundwater

Barraclough and others (1967a) 1965 Extent of perched groundwater and distribution of selected wastewater 

constituents in perched groundwater at the TRA

Barraclough and others (1967b) 1966 Extent of perched groundwater and distribution of selected wastewater 

constituents in perched groundwater at the TRA

Robertson and others (1974) NA Analysis of perched groundwater and conditions related to the disposal of 

wastewater to the subsurface at the INEL

Barraclough and Jensen (1976) NA Extent of perched groundwater and distribution of selected wastewater 

constituents in perched groundwater at the TRA

Robertson (1976) NA Numerical model simulating flow and transport of chemical and 

radionuclide constituents through perched water at the TRA

Barraclough and others (1981) 

http://pubs.er.usgs.gov/publication/wsp2191

1974–78 Hydrologic conditions for the INEL, Idaho

Lewis and Jensen (1985) 1979–81 Hydrologic conditions for the INEL, Idaho

Pittman and others (1988)

http://pubs.er.usgs.gov/publication/wri894008

1982–85 Hydrologic conditions for the INEL, Idaho

Hull (1989) NA Conceptual model that described migration pathways for wastewater 

andconstituents from the radioactive-waste infiltration ponds at the TRA

Anderson and Lewis (1989)

http://pubs.er.usgs.gov/publication/wri894065

NA Correlation of drill cores and geophysical logs to describe a sequence 

of basalt flows and sedimentary interbeds in the unsaturated zones 

underlying the RWMC

Anderson (1991)

http://pubs.er.usgs.gov/publication/wri914010

NA Correlation of drill cores and geophysical logs to describe a sequence 

of basalt flows and sedimentary interbeds in the unsaturated zones 

underlying the TRA, and INTEC

Ackerman (1991b)

http://pubs.er.usgs.gov/publication/wri914058

NA Analyzed data from 43 aquifer tests conducted in 22 wells to estimate 

transmissivity of basalts and sedimentary interbeds containing perched 

groundwater beneath the TRA and INTEC

Cecil and others (1991)

http://pubs.er.usgs.gov/publication/wri914166

1986–88 Mechanisms for formation of perched water at the TRA, ICPP, and 

RWMC, INEL, Idaho; distribution of chemical and radiochemical 

constituents in perched water at the TRA, ICPP and RWMC

Tucker and Orr (1998)

http://pubs.er.usgs.gov/publication/wri984028

1989–91 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in perched groundwater, INEL, Idaho

Bartholomay (1998)

http://pubs.er.usgs.gov/publication/wri984026

1992–95 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in perched groundwater, INEL, Idaho

Orr (1999)

http://pubs.er.usgs.gov/publication/wri994277

NA Transient numerical simulation to evaluate a conceptual model of flow 

through perched water beneathe wastewater infiltration ponds at the 

TRA

Bartholomay and Tucker (2000)

http://pubs.er.usgs.gov/publication/wri004222

1996–98 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in perched groundwater, INEEL, Idaho

Davis (2006a)

http://pubs.er.usgs.gov/publication/sir20065236

1999–2001 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in perched groundwater, INL, Idaho

Davis (2008)

http://pubs.er.usgs.gov/publication/sir20085089

2002–05 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho

Davis (2010)

http://pubs.er.usgs.gov/publication/sir20105197

2006–08 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho

Davis and others (2013) 2009–11 Hydrologic conditions and distribution of selected radiochemical and 

chemical constituents in groundwater and perched groundwater, INL, 

Idaho
Methods 7

Some qualitative information about trends of selected 

constituents for selected wells is given in the more recent 

hydrologic conditions reports listed in table 1, and trend 

data are given in Davis and others (2013) for wastewater 

constituents in water from several wells that are affected 

by wastewater disposal. Trends for most of the constituents 

plotted show decreasing concentrations because of the changes 

in the methods of disposal, dilution, and dispersion in the 

aquifer, and reductions of amounts of constituents being 

discharged. One exception is increasing trends in carbon 

tetrachloride concentration in two wells at the RWMC (Davis 

and others, 2013, fig. 29). 

Knobel (2006) plotted water-quality data from 1990 

through 2003 for 30 wells downgradient of the INTEC to 

visually compare historical water-quality data collected 

after purging three well volumes with water-quality data 

collected after purging one well volume. Qualitative and 

quantitative evaluations indicated that the water-quality data 

were comparable for the different purge volumes for the 

30 wells studied. 

Concentration trends for selected wells not affected by 

wastewater disposal at the INL are given for iron, zinc, and 

nitrate in U.S. Department of Energy (2010). That study 

indicated that the use of galvanized pipes in some of the wells 

probably is responsible for elevated zinc concentrations. 

Nitrate concentrations were plotted for wells USGS 2, 100, 

and 101, and the increasing trends were attributed to long-term 

agricultural practices northeast of the INL. 

Neher and others (1998) plotted water-quality data 

collected by the USGS from 1960 through 1995 for 66 wells 

near facilities at the INL and wells near the southern boundary 

of the INL to assist the scientific community in identifying 

issues that may require additional investigation and to provide 

a reference document for individuals interested in the water 

quality of the ESRP aquifer near the INL. Radionuclide data 

and inorganic chemicals that were commonly disposed at the 

INL and specific conductance measurements also were plotted 

by Neher and others (1998). 

Bartholomay and others (2012) used statistical methods 

to determine trends for selected constituents for 67 wells and 

7 surface-water sites sampled by the USGS at the INL that 

probably were not affected by wastewater disposal at the INL. 

They determined that chloride trends in wells influenced by 

recharge from the Big Lost River either decreased or had 

variable increases and decreases due to wet and dry cycles of 

precipitation and runoff. Wells influenced by regional recharge 

showed increasing trends for chloride, sodium, sulfate, and 

nitrate and the increases were attributed to agricultural or 

other anthropogenic influences upgradient of the INL. Some 

wells near the NRF and Power Burst Facility (PBF) showed 

increasing trends possibly due to wastewater disposal at 

those facilities. 

Methods

Sample Collection and Analyses

Water samples analyzed for this study were collected 

from 64 ESRP aquifer wells (figs. 2 and 3) and 35 perched 

groundwater wells (fig. 4). Since 1989, water samples 

have been analyzed for chemical constituents at the USGS 

National Water Quality Laboratory (NWQL) in Lakewood, 

Colorado. Prior to 1989, water samples were analyzed by 

various laboratories for chloride, chromium, sodium, and 

nitrate (Wegner, 1989). Water samples have been analyzed 

for radiochemical constituents at the DOE Radiological and 

Environmental Sciences Laboratory (RESL) at the INL since 

samples were first collected. Many of the samples collected 

in the 1950s, 1960s, and 1970s were collected during or 

immediately after cable-drilling, and there was a high 

probability that some of the samples contained impurities 

introduced by the drilling (Robertson and others, 1974, 

appendix B). Some chemical and radiochemical analyses for 

special studies have been done at the NWQL and by contract 

laboratories throughout the history of the USGS monitoring 

program at the INL, but those data were not considered for 

statistical trend analysis in this study because of the variability 

of method detection levels and the analytical methods used. 

Until 2008, the RESL reported an uncertainty of 2s, where s

is the sample standard deviation, for water samples analyzed 

for radionuclides, and data were entered into the USGS 

National Water Information System (NWIS) database with that 

uncertainty. In 2008, the RESL began reporting the uncertainty 

as 1s, and data are now entered into NWIS with the 1s

uncertainty. Analytical uncertainties in this report are reported 

as 1s for consistency. 

Methods used to sample and analyze for selected 

constituents generally follow the guidelines established by 

the USGS (Goerlitz and Brown, 1972; Stevens and others, 

1975; Wood, 1976; Thatcher and others, 1977; Claassen, 1982; 

Wershaw and others, 1987; Fishman and Friedman, 1989; 

Faires, 1993; Fishman, 1993; and U.S. Geological Survey, 

variously dated). Water samples were collected according to a 

quality-assurance plan for water-quality activities conducted 

by personnel at the USGS INL Project Office. The plan was 

finalized in June 1989 and revised in March 1992, in 1996 

(Mann, 1996), in 2003 (Bartholomay and others, 2003), in 

2008 (Knobel and others, 2008), and in 2014 (Bartholomay 

and others, 2014). The plan is available for inspection at the 

USGS INL Project Office. 

Field processing of water samples differed 

depending on the constituents for which analyses were 

requested and the time period in which they were collected. 
8 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig02

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 3 and 4 

See figures 3 and 4

ATR Complex 

INTEC

MFC

NRF

TAN

RWMC

PBF

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

108 105 

104 

RWMC M14S 

Rifle 

Range 

RWMC

M13S 

RWMC

M12S 

RWMC M11S 

106 127 

CFA 1 CFA 2 

EXPLANATION

RWMC M14S

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifierNumber indicates only

 USGS well, other 

names are local well 

names

MFC Materials and Fuels Complex

PBF Power Burst Facility

TAN Test Area North

NRF Naval Reactors Facility

Inset areas for selected facilities at the Idaho National Laboratory—See figure 3 and 4.

RWMC Radioactive Waste Management Complex

ATR Complex Advanced Test Reactor Complex

INTEC Idaho Nuclear Technology and Engineering Center

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 2. Locations of wells in the eastern Snake River Plain aquifer at and near the Idaho National Laboratory, Idaho.
Methods 9

tac14-0956_fig03

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Old percolation

ponds

New percolation

ponds

Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

RWMC M1SA 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 Meters

0 3,000 Feet

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43 ̊

30’

43 ̊

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Figure 3. Locations of wells in the eastern Snake River Plain aquifer at and near the Advanced Test 

Reactor Complex, the Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, Idaho National Laboratory, Idaho.
10 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig04

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 6

PW 7

PW 1

PW 3

PW 4

PW 2

PW 5

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 Feet

1,000 Meters

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 2

CWP 4

CWP 5

TRA A13

TRA A77

Figure 4. Locations of perched groundwater wells at and near the Advanced Test Reactor Complex, the Idaho Nuclear 

Technology and Engineering Center, and the Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Methods 11

Water samples analyzed by the NWQL were placed in 

containers and preserved in accordance with laboratory 

requirements specified by Timme (1995) and Knobel and 

others (2008, appendix A). Containers and preservatives for 

samples collected since 1989 were supplied by the NWQL 

and were processed using a rigorous quality-control procedure 

(Pritt, 1989, p. 75) to minimize sample contamination. 

Water samples requiring filtration were filtered through 

disposable 0.45-μm plate filters or cartridge filters that were 

pre-rinsed depending on the sample protocol at the time of 

collection. Water samples analyzed by the RESL were placed 

in containers and preserved in accordance with laboratory 

requirements specified by Bodnar and Percival (1982), 

U.S. Department of Energy (1995), and Knobel and others 

(2008, appendix A).

Sample collection methods varied for several of the 

wells during the history of sampling. Permanent pumps were 

installed at various dates (table 2), with most installations 

occurring between 1985 and the early 1990s. Prior to 

installation of pumps, wells were sampled using a portable 

thief sampler. Some of the samples collected with thief 

samplers were collected at different depths in the aquifer 

during the same sampling period. When the depths at which 

thief samples were collected were known, the data from 

the depth similar to the depth setting of the current pump 

were used in the analyses. After pumps were installed, wells 

were purged for at least three well volumes prior to sample 

collection until October 2003, when procedures were changed 

to allow sample collection after one well volume was purged 

and readings were stable for water temperature, pH, and 

specific conductance. Studies by Bartholomay (1993) and 

Knobel (2006) indicated that different purge rates used at the 

INL did not affect the analytical results for the wells analyzed 

in the respective studies. 

The methods used to preserve samples collected for 

nutrient analyses also changed over time. Until October 

1994, samples collected for nutrients were analyzed at the 

NWQL and preserved with mercuric chloride and chilling. 

After October 1994, samples were preserved only by chilling. 

Bartholomay and Williams (1996) compared preservation 

methods, and their results indicated that data were comparable 

between the two methods. 

Sample collection frequency varied for all sites used in 

this study. Since 2003, all sites have been sampled annually, 

but prior to that timeframe, wells were sampled annually, 

semi-annually, quarterly, or more frequently depending on 

the purpose of the sampling program. Some gaps in data 

occur when pumps were out for repair, samples were lost, or 

program changes did not call for sampling of the constituent 

in question. 

Quality Assurance/Quality Control 

Beginning in 1980, about 10 percent of water samples 

were collected for quality assurance (QA) purposes. Quality 

control (QC) water samples collected by the USGS INL 

Project Office generally include equipment blanks, splits, and 

replicates; however, other types of QC samples also have been 

collected throughout the history of the program. Comparative 

studies to determine agreement between analytical results for 

water-sample pairs by laboratories used by the INL Project 

Office QA program were summarized by Wegner (1989); 

Williams (1996, 1997); Rattray (2012); Davis and others, 

(2013); and Rattray (2014). Wegner (1989) also statistically 

compared analytical results among different laboratories 

used from 1980 to 1988. Analyses of water-sample pairs 

were in statistical agreement for more than 95 percent of the 

samples compared. Some outliers occurred; in cases where 

replicates were collected, data from the samples with the most 

reasonable result compared with the long-term trend were used 

in the trend analyses. 

Guidelines for Interpretation of 

Analytical Results 

Concentrations of radionuclides are reported with an 

estimated sample standard deviation, s, which is obtained by 

propagating sources of analytical uncertainty in measurements. 

McCurdy and others (2008) provided details on interpreting 

radiological data used by the USGS. The guidelines for 

interpreting analytical results are based on an extension of 

a method proposed by Currie (1984) and are given in Davis 

and others (2013). In this report, radionuclide concentrations 

of less than 3s are considered to be less than the “reporting 

level.” The reporting level should not be confused with 

the analytical method detection limit, which is based on 

laboratory procedures. 

Concentrations of inorganic and organic constituents are 

reported with reference to long term method detection levels 

(LT-MDL), LRL, and interim reporting levels (IRLs), or with 

reference to minimum reporting levels (MRLs). Childress and 

others (1999) provided details about the approach used by the 

USGS regarding detection and reporting levels. The USGS 

Office of Water Quality Technical Memorandum 2010.07 

(U.S. Geological Survey, 2010) outlines changes to data 

reporting by the NWQL for inorganic and organic constituents. 

The primary change was that the reporting level for most 

inorganic constituents was set at the LT-MDL. The method 

detection limit is the minimum concentration of a substance 

that can be measured and reported with 99-percent confidence 

that the concentration is greater than zero. The LRL is 

the concentration at which the false negative error rate is 

minimized to be no more than 1 percent of the reported results. 

The MRL uses a censor-limit based reporting level below 

which no data are reported and is set at a concentration greater 

than the detection limit of the analyte. The LRL generally 

is equal to twice the yearly determined LT-MDL, which is a 

detection level derived by determining the standard deviation 

of a minimum of 24 MDL spike-sample measurements over 

an extended time. These reporting levels may be described as 

preliminary (IRL) for a developmental method if the levels 

have been based on a small number of analytical results. 
12 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 2. Site information for wells at and near the Idaho National Laboratory, Idaho.

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier 

used to access well data from the U.S. Geological Survey National Water Information System (http://waterdata.usgs.gov/nwis). Pump 

installation date: Date the first pump was installed in the well. Abbreviations: ft BLS, feet below land surface; NWQL, National Water 

Quality Laboratory; RESL, Radiological and Environmental Sciences Laboratory; NA, not applicable]

Sampling sites Well depth

(ft BLS)

Period of record Pump 

installation

date

NWQL 

chemical data

RESL 

radiochemical data Local name Site identifier

Aquifer wells

Idaho Nuclear Technology and Engineering Center

CPP 1 433433112560201 586 1977–2012 1972–2012 12-07-1950

CPP 2 433432112560801 605 1981–2012 1972–2012 03-12-1951

RIFLE RANGE 433243112591101 620 1988–2012 1988–2012 06-29-1988

USGS 20 433253112545901 658 1968–2012 1966–2012 09-07-1990

USGS 34 433334112565501 700 1977–2012 1966–2012 08-14-1990

USGS 35 433339112565801 579 1977–2012 1972–2012 08-09-1990

USGS 36 433330112565201 567 1977–2012 1966–2012 08-14-1990

USGS 37 433326112564801 572 1971–2012 1966–2012 06-19931

USGS 38 433322112564301 612 1977–2012 1966–2012 09-26-1990

USGS 39 433343112570001 493 1977–2012 1972–2012 08-09-1990

USGS 40 433411112561101 483 1977–2010 1972–2010 07-19801

USGS 41 433409112561301 674 1977–2012 1972–2012 08-15-1990

USGS 42 433404112561301 678 1977–2012 1972–2012 08-15-1990

USGS 43 433415112561501 676 1977–2012 1972–2012 07-19801

USGS 44 433409112562101 650 1977–2012 1967–2012 07-02-1990

USGS 45 433402112561801 651 1977–2012 1972–2012 07-26-1990

USGS 46 433407112561501 651 1977–2012 1972–2012 07-26-1990

USGS 47 433407112560301 652 1977–2012 1972–2012 10-19751

USGS 48 433401112560301 750 1977–2012 1972–2012 08-08-1990

USGS 51 433350112560601 647 1960–2012 1972–2012 06-26-1987

USGS 52 433414112554201 602 1977–2012 1972–2012 06-24-1987

USGS 57 433344112562601 582 1971–2012 1972–2012 06-23-1987

USGS 59 433354112554701 657 1977–2012 1972–2012 06-24-1987

USGS 67 433344112554101 694 1977–2012 1972–2012 07-19801

USGS 77 433315112560301 586 1968–2012 1966–2012 07-26-1990

USGS 82 433401112551001 693 1984–2012 1972–2012 06-25-1987

USGS 84 433356112574201 505 1984–2012 1972–2012 07-29-1992

USGS 85 433246112571201 614 1968–2012 1966–2012 08-23-1990

USGS 111 433331112560501 560 1986–2012 1985–2012 01-22-1985

USGS 112 433314112563001 563 1986–2012 1985–2012 01-26-1985

USGS 113 433314112561801 564 1986–2012 1985–2012 01-25-1985

USGS 114 433318112555001 560 1986–2012 1985–2012 01-24-1985

USGS 115 433320112554101 581 1986–2012 1985–2012 01-23-1985

USGS 116 433331112553201 572 1986–2012 1985–2012 01-30-1985

USGS 123 433352112561401 481 1991–2012 1991–2012 04-05-1994

USGS 128 433250112565601 615 2001–2012 2001–2012 08-19-2002

Advanced Test Reactor Complex

MTR TEST 433520112572601 588 1984–2012 1972–2012 01-15-1986

TRA Disposal 433506112572301 1,267 1986–2012 1985–2012 02-04-1986

USGS 58 433500112572502 503 1977–2012 1962–2012 01-16-1986

USGS 65 433447112574501 498 1967–2012 1969–2012 10-05-1977

USGS 76 433425112573201 718 1981–2012 1972–2012 01-17-1986

USGS 79 433505112581901 702 1984–2012 1972–2012 08-23-1990
Methods 13

Table 2. Site information for wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier 

used to access well data from the U.S. Geological Survey National Water Information System (http://waterdata.usgs.gov/nwis). Pump 

installation date: Date the first pump was installed in the well. Abbreviations: ft BLS, feet below land surface; NWQL, National Water 

Quality Laboratory; RESL, Radiological and Environmental Sciences Laboratory; NA, not applicable]

Sampling sites Well depth

(ft BLS)

Period of record Pump 

installation

date

NWQL 

chemical data

RESL 

radiochemical data Local name Site identifier

Aquifer wells—Continued

Central Facilities Area

CFA 1 433204112562001 639 1970–2012 1966–2012 07-19431

CFA 2 433144112563501 681 1977–2012 1966–2012 01-18-1949

CFA LF 3-9 433216112571001 500 1993–2007 1993–2007 07-19941

CFA LF 2-10 433216112563301 716 1993–2012 1993–2012 06-26-1991

USGS 127 433058112572201 596 2000–2012 2000–2012 09-12-2000

Radioactive Waste Management Complex

RWMC M1SA 432956113030901 638 1993–2012 1993–2012 08-27-1992

RWMC M3S 433008113021801 633 1993–2012 1993–2012 09-04-1992

RWMC M7S 433023113014801 628 1993–2012 1993–2012 09-01-1992

RWMC M11S 433058113010401 624 2000–2012 2000–2012 19981

RWMC M12S 433118112593401 572 2000–2012 2000–2012 19981

RWMC M13S 433037113002701 643 2000–2012 2000–2012 19981

RWMC M14S 433052113025001 635 2000–2012 2000–2012 19981

RWMC Production 433002113021701 685 1981–2012 1977–2012 11-25-1974

USGS 87 433013113024201 673 1977–2012 1972–2012 10-19741

USGS 88 432940113030201 662 1981–2011 1972–2011 10-19741

USGS 89 433005113032801 637 1981–2012 1972–2012 07-19751

USGS 120 432919113031501 705 1987–2012 1987–2012 11-12-1987

South of facilities

USGS 104 432856112560801 700 1984–2012 1980–2012 01-27-1986

USGS 105 432703113001801 1,290 1981–2007 1980–2007 11-19831

USGS 106 432959112593101 760 1981–2012 1980–2012 01-13-1981

USGS 108 432659112582601 1,192 1984–2008 1980–2008 11-19831

USGS 124 432307112583101 800 1994–2012 1994–2012 04-19941

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center

PW 1 433349112560701 117 1989–2002 1987–2002 NA

PW 2 433344112555601 131 1989–2002 1987–2002 NA

PW 3 433351112555701 123 1989–2002 1987–2002 NA

PW 4 433348112554901 150 1989–2007 1987–2006 06-15-1992

PW 5 433348112555701 129 1989–2002 1987–2002 09-28-1993

PW 6 433353112562201 125 1989–2000 1987–2000 NA

USGS 50 433419112560201 405 1977–2008 1967–2008 12-19941

Advanced Test Reactor Complex

CWP 1 433459112572601 58 1989–2012 1982–2012 NA

CWP 2 433458112572401 50 1989–2001 1983–2001 NA

CWP 3 433455112572501 55 1989–2012 1982–2012 NA

CWP 4 433454112572601 61 1989–2010 1982–2010 NA

CWP 5 433455112572901 52 1989–2001 1982–2001 NA

CWP 8 433500112573001 64 1989–2012 1982–2012 NA

PW 7 433446112574602 237 1987–1994 NA NA

PW 8 433456112572001 166 1989–2012 1987–2012 06-15-1992

PW 9 433500112575401 200 1987–2012 1987–2012 06-15-1992
14 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 2. Site information for wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier 

used to access well data from the U.S. Geological Survey National Water Information System (http://waterdata.usgs.gov/nwis). Pump 

installation date: Date the first pump was installed in the well. Abbreviations: ft BLS, feet below land surface; NWQL, National Water 

Quality Laboratory; RESL, Radiological and Environmental Sciences Laboratory; NA, not applicable]

Sampling sites Well depth

(ft BLS)

Period of record Pump 

installation

date

NWQL 

chemical data

RESL 

radiochemical data Local name Site identifier

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

TRA A13 433502112572802 59 1989–2001 1972–2001 NA

TRA A77 433507112573801 34 1989–1997 1972–1997 NA

USGS 53 433503112573401 71 1981–2012 1968–2012 08-08-1990

USGS 54 433503112572801 82 1981–2012 1962–2012 10-12-1993

USGS 55 433508112573001 81 1981–2012 1962–2012 09-23-1993

USGS 56 433509112573501 80 1981–2012 1962–2012 09-28-1993

USGS 60 433456112571901 117 1984–2011 1966–2011 06-15-1992

USGS 61 433453112571601 123 1986–2012 1966–2012 06-16-1992

USGS 62 433446112570701 165 1984–2012 1962–2012 06-17-1992

USGS 63 433455112574001 97 1986–2012 1962–2012 06-16-1992

USGS 66 433436112564801 475 1989–2012 1966–2012 NA

USGS 68 433516112573901 128 1962–2012 1972–2012 06-16-1992

USGS 69 433450112573001 115 1986–2012 1967–2012 06-16-1992

USGS 70 433504112571001 100 1981–2012 1962–2012 06-17-1992

USGS 71 433439112571501 171 1987–2012 1962–2012 06-17-1992

USGS 72 433519112574601 200 1989–2012 1974–2012 09-23-1993

USGS 73 433502112575401 127 1986–2012 1962–2012 20031

USGS 78 433413112573501 204 1986–2012 1972–2012 NA

Radioactive Waste Management Complex

USGS 92 433000113025301 214 1972–2012 1972–2012 NA

1

Estimated date based on month or year of initial installation.

These levels also may vary from sample to sample for the 

same constituent and the same method, if matrix effects 

or other factors arise that interfere with the analysis. 

Concentrations measured between the LT-MDL and the LRL 

may be described as estimated values and are considered 

“qualitatively detected analytes” (Childress and others, 1999, 

p. 7). For most of the constituents in this report, concentrations 

generally are greater than the LT-MDLs, LRLs, or MRLs; 

however, some concentrations are reported as less than the 

LT-MDL or LRL and some concentrations are estimated. 

Statistical Data Analysis Methods

Water-quality data collected for the monitoring program 

were analyzed using the summary statistics of mean, median, 

minimum, maximum, and standard deviation. The data 

were processed using custom computer scripts developed in 

the R programming language (R Development Core Team, 

2014). All R functions written for this report are stored in an 

R-package called “Trends” (Fisher and Davis, 2014); function 

documentation and processing instructions for this package are 

given in appendix A. R-package installation instructions are 

located at https://github.com/jfisher-usgs/Trends/blob/master/

README.md.

 In addition to the base packages included with R, 

Trends depends on the “Survival” package (Therneau and 

Grambsch, 2000; Therneau, 2014), a contributed package 

available on the Comprehensive R Archive Network. The 

Trends package identifies statistical trends in water-quality 

data for multiple constituents and sample sites using a 

parametric survival regression model for left-censored data 

(values reported as less than a LRL), interval-censored data 

(data with an associated uncertainty), and uncensored data. 

This package also calculates summary statistics for multiple 

constituents and automates plotting of data and regression 

lines. A measured value is converted to censored data under 

the following conditions: (1) the measured value is less 

than the reporting level and is represented as left-censored 

data; or (2) there is a standard deviation and detection limit 

associated with the measured value; therefore, it is represented 

as interval-censored data. The upper and lower bounds of 

interval-censored data are calculated by adding and subtracting 
Methods 15

three standard deviations to or from the measured value, 

respectively. Note that interval-censored data with a lower 

or upper bound less than the detection level is represented as 

left-censored data. For left-censored data, the upper bound is 

set to the detection level when its magnitude is less than the 

detection level. For datasets with estimated (E) concentrations, 

the E-value was treated the same as a concentration for an 

uncensored value. 

Data were analyzed using the “RunAnalysis” function in 

the Trends package (appendix A), which uses the “survreg” 

function provided in the survival package. The survreg 

function uses methods to manage statistics for left-censored, 

interval-censored, and uncensored environmental data. 

The survreg function was used to fit a parametric survival 

regression model to the censored and uncensored data. The 

specific class of survival model is known as the accelerated 

failure time (AFT) model. A maximum-likelihood estimation 

(MLE) method is used to estimate parameters in the AFT 

model. The MLE is solved by maximizing the log-likelihood 

using the Newton-Raphson method, an iterative root-finding 

algorithm. The likelihood function is dependent on the 

distribution of the measured data. Data were assumed to 

follow a log-normal distribution because most of the variables 

have values spanning two or more orders of magnitude. If all 

observations are uncensored, the survival regression becomes 

identical to ordinary least squares regression. Summary 

statistics were not calculated for constituents when all 

concentrations were less than the reporting level. 

The null hypothesis of the trend test was that the slope 

(the coefficient relating time and concentration) was zero; 

the alternate hypothesis was that the slope was not zero. A 

significance level of 0.05 was selected to determine if the 

slope was statistically significant. A two-sided p-value that 

was less than or equal to 0.05 indicated that there was a 

statistically significant slope, and the null hypothesis was 

rejected. The p-value is the linear trend over time for each 

dataset run. The sign of the slope indicated if there was an 

increasing or decreasing trend. If p-values were greater than 

0.05, the slope was not statistically significant, and the null 

hypothesis was accepted. In some cases, the regression model 

could not determine if a trend was present because the AFT 

model failed to reach convergence after 100 iterations; no 

trend was assumed present when this occurred.

For selected datasets, water level, seasonal variability in 

sampling, and water level and seasonal variability were used 

as explanatory variables in the survival regression model. 

Results for p-values for comparison are given in table 3, and 

the description of the analyses is given in the Trends package 

in appendix A.

Table 3. Comparison of trend analyses for selected wells using additional explanatory 

variables, included as covariates to the trend model, Idaho National Laboratory, Idaho.

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Trend: +, 

increasing; –, decreasing. p value is for linear trend over time. Reg: p values for temporal trend analyses done 

for this study. WL: p values for trend with residual water level as an additional explanatory variable. Seasonal:

p values for trends with seasonality as an additional explanatory variable. WL and seasonal: p values for trend 

with both residual water levels and seasonality as additional explanatory variables] 

Local 

name Reg Trend WL Trend Seasonal Trend WL and seasonal Trend

Chloride

USGS 35 0.000 – 0.000 – 0.000 – 0.000 –

USGS 39 0.128 none 0.481 none 0.076 none 0.674 none

USGS 114 0.000 + 0.000 + 0.000 + 0.000 +

USGS 87 0.000 + 0.000 + 0.000 + 0.000 +

PW 8 0.089 none 0.124 none 0.051 none 0.061 none

Sulfate

USGS 35 0.000 + 0.019 + 0.000 + 0.019 +

USGS 39 0.000 + 0.049 + 0.000 + 0.085 none

USGS 114 0.177 none 0.180 none 0.244 none 0.262 none

USGS 87 0.546 none 0.368 none 0.684 none 0.616 none

PW 8 0.049 – 0.009 – 0.003 – 0.001 –

Sodium

USGS 35 0.002 – 0.000 – 0.014 – 0.004 –

USGS 39 0.026 + 0.030 + 0.033 + 0.070 none

USGS 114 0.173 none 0.162 none 0.190 none 0.194 none

USGS 87 0.000 + 0.000 + 0.000 + 0.000 +

PW 8 0.420 none 0.619 none 0.461 none 0.696 none
16 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Water-Quality Characteristics and 

Trends

Concentrations of constituents reported during this study 

represent water samples collected at different time intervals, 

starting in 1981 when known detection levels were used for 

radiochemical analyses, and continuing through 2012. Data 

used for selected plots of trend analyses (appendixes B–E) 

included all data identified as being reported by the NWQL or 

RESL that was in the NWIS database as of December 2013, 

except for some data that were identified as coming from 

special INL studies or data collected from different depths 

in the aquifer using a thief sampler. Wells were completed 

at various depths in the aquifer and with different well 

completions (for example, single and multiple screened 

intervals and open boreholes). Data included in NWIS but 

analyzed by different or unknown laboratories were not used. 

Data analyzed by the NWQL are routinely uploaded to the 

NWIS database; however, data from RESL were manually 

entered from paper copies until 2009. Trends were initially 

analyzed for entire datasets, but analyses of some wells 

seemed to indicate that pump installation created a change 

in the concentrations of some constituents (Bartholomay 

and others, 2012). Therefore, trends were determined for the 

period of record from some time after a pump was installed 

and all samples were analyzed by the NWQL (for nonradiochemical data). Some well pumps were installed for the 

entire period of record, but trends were analyzed only for 

data collected from between 1987 and 1989 (depending on 

the constituents) to 2012 for those wells because some of the 

earlier data appeared suspect or samples were analyzed by 

different laboratories with undocumented methods. Between 

1987 and 1989, the USGS INL Project Office began using 

the NWQL for all organic and inorganic chemical analyses, 

and an established quality-assurance program was used to test 

sample variability and reproducibility. Trends for tritium and 

strontium-90 concentration data were analyzed for samples 

collected from 1981 to 2012 because samples collected prior 

to 1981 had unknown detection levels. The trends described 

in this report were based on statistical methods previously 

described in the statistical methods section of this report. For 

some datasets, the slope of the line or the visual appearance of 

the graphed data based on scale make it appear like there is a 

trend, when statistically, there is no trend. 

Physical properties of water measured during sampling 

events included specific conductance, water temperature, 

and pH. Samples collected from wells included in this study 

were analyzed for some combination of the radiochemical 

and chemical constituents tritium, strontium-90, cesium-137, 

plutonium-238, plutonium-239, -240 (undivided), 

americium-241, gross alpha- and beta-particle radioactivity, 

sodium, chloride, fluoride, sulfate, nitrate (as N), 

orthophosphate (as P), chromium and other trace elements, 

TOC, and VOCs. Other constituents have been sampled at some 

of the wells, but data were not used because concentrations 

were either less than the reporting levels (in the case of some 

VOCs) or because data were insufficient to determine a 

statistically significant trend.

pH, Specific Conductance, and Temperature

Field measurements of pH, specific conductance, and 

water temperature were made in all 64 aquifer wells and 

35 perched groundwater wells used for this study (figs. 2, 3, 

and 4). Summary statistics for the field measurements for 

1989–2012 are given in table 4 (at back of report). Analyses 

for pH, specific conductance, and water temperature for the 

datasets are shown in appendix B. 

Analyses of trends for pH indicate that many sites have 

statistically significant decreasing trends (table 4, appendix B). 

Of the 64 aquifer wells measured for pH, 43 of the wells 

showed a decreasing trend, 1 well showed an increasing trend, 

and 20 wells showed no trend. Of the 35 perched groundwater 

wells measured, 12 showed a decreasing pH trend, 3 showed an 

increasing trend, and 20 had no trend.

 The pH is an indicator of hydrogen ion activity and is 

collected to understand the acid-base properties of water. 

Factors that may affect the precision of pH readings include 

careful attention to the electrode maintenance, buffer solutions, 

temperature corrections, instrument electronics, use of different 

meter brands, and collection methods. Because of variability 

in each of these factors throughout the history of sample 

collection, it is difficult to determine specifically whether the 

noted trends in pH are actually attributable to changing aquifer 

conditions or other factors.

Specific conductance is a measure of the electrical 

conductivity of water and is proportional to the quantities of 

dissolved chemical constituents in the water so trends in this 

measurement should be similar to the trends for chloride, 

sodium, and sulfate concentrations. 

Trend analyses of specific conductance from 1989 to 2012 

are shown in appendix B. The aerial distribution of trends in 

specific conductance for aquifer and perched groundwater 

wells sampled from 1989 to 2012 are shown in figures 5, 6, 

and 7. For the 64 aquifer wells (figs. 5 and 6, table 4) that 

were measured for specific conductance, 34 had a decreasing 

trend, 14 had an increasing trend, and 16 had no trend. Most 

of the wells that showed decreasing or no trend are near the 

INTEC. The decreasing trends may be a response to decreased 

wastewater disposal since 1989 or discontinued use of the 

percolation ponds south of the INTEC in 2002. Most aquifer 

wells that showed an increasing trend are south and southeast 

of the INTEC, or north of the RWMC. Increasing trends for 

these wells may be the result of longer groundwater travel times 

required for the wastewater plume to reach these wells.
Water-Quality Characteristics and Trends 17

tac14-0956_fig05

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 6 and 7 

See figures 6 and 7

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

105 108 

104 

RWMC M14S 

Rifle

Range 

RWMC

M13S 

RWMC

M12S RWMC M11S 

106 127 

CFA 2 CFA 1 

Color of identifier is indicator of specific conductance 

measurement trend; red color indicates increasing trend; 

green indicates decreasing trend; and black indicates no 

trend

108 

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information

MFC—Materials and Fuels Complex 

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 5. Areal distribution of specific conductance trends in water from selected aquifer wells at and near the Idaho 

National Laboratory, Idaho.
18 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig06

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation

ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 37 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

RWMC M1SA 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43 ̊

30’

43 ̊

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Color of identifier is indicator of specific conductance 

measurement trend; red color indicates increasing trend;

green indicates decreasing trend; and black indicates no 

trend

Figure 6. Areal distribution of specific conductance trends in water from selected aquifer wells 

at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 19

tac14-0956_fig07

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 6

PW 7

PW 1

PW 3

PW 4

PW 2

PW 5

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 FEET

1,000 METERS

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 2

CWP 4

CWP 5

TRA A13

TRA A77

Color of identifier is indicator of specific conductance 

measurement trend; red color indicates increasing trend; 

green indicates decreasing trend; and black indicates no 

trend

Figure 7. Areal distribution of specific conductance trends in water from selected perched groundwater wells at 

the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, the Idaho National Laboratory, Idaho.
20 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Most trends of specific conductance in perched 

groundwater wells near the INTEC and the ATR Complex 

were either decreasing or showed no trend (fig. 7, table 4). 

Only one well at each facility (TRA A77 at the ATR Complex, 

and PW 6 at the INTEC) had an increasing trend. At the 

INTEC, the decreasing trend could be attributed to decreased 

wastewater disposal or discontinued use of the percolation 

ponds. At the ATR complex, the decrease could be due to 

closure of the chemical-waste pond (fig. 7) in 1999. 

For the 64 aquifer wells measured for statistically 

significant trends in water temperature, 32 showed a 

decreasing trend, 3 showed an increasing trend, and 29 showed 

no trend (figs. 8 and 9). Most wells around INTEC showed a 

decreasing trend, the cause of which is not certain, although 

changes could be related to the method of measurement and 

not to actual changes in the temperature of the aquifer for 

some of the wells. For example, temperature measurements 

made prior to 2003 were measured using a sample cup with 

a mercury thermometer, whereas recently, temperature 

was measured using a flow-through chamber with a digital 

thermometer. Of the 35 perched groundwater wells measured 

for temperature, 13 had a decreasing trend, 5 showed an 

increasing trend, and 17 showed no trend. All the perched 

groundwater wells that showed an increasing or decreasing 

trend were near the ATR Complex (fig. 10), but no pattern of 

trend is evident for a specific location.

Tritium

Tritium is a radioactive isotope of hydrogen that is 

formed in nature by interactions of cosmic rays with gases 

in the upper atmosphere (Orr and others, 1991). Tritium also 

is produced in thermonuclear detonations, and it has been 

discharged in wastewater at several facilities at the INL 

from the early 1950s to the present. Tritium has a half-life of 

12.3 years (Walker and others, 1989, p. 20). Samples were 

routinely collected and analyzed for tritium from 63 aquifer 

wells and 33 perched groundwater wells. 

Of the 63 aquifer wells that were analyzed for tritium 

trends, 45 showed decreasing trends, 1 showed an increasing 

trend, and 17 showed no trends (figs. 11 and 12) (table 5, at 

back of report). Of the 33 perched groundwater wells that 

were analyzed for trends, 22 showed a decreasing trend, 

and 11 showed no trend (fig. 13). The decreasing trends 

can be attributed to decreased disposal at facilities, and to 

the radioactive decay of tritium. A lack of trend is evident 

around the RWMC area (fig. 12). This may be an indication 

that leakage from buried waste is still contributing tritium to 

groundwater in this area and maintaining the concentration 

at a higher level than would be expected from radioactive 

decay. Some wells in RWMC area show no trend because 

concentrations in those wells always have been less than the 

reporting level.

Strontium-90

Strontium-90 is a fission product of nuclear weapons tests 

that is present in wastewater discharged at several facilities 

at the INL (Davis, 2010). Strontium-90 has a half-life of 

29.1 years (Walker and others, 1989, p. 29). Water samples 

have been routinely collected and analyzed for strontium-90 

from 52 aquifer wells and 32 perched groundwater wells.

Of the 52 aquifer wells analyzed for trends, 20 showed 

a decreasing strontium-90 trend and 32 showed no trend 

(figs. 14 and 15, table 5). Of the 32 perched groundwater 

wells that were analyzed for trends, 11 showed a decreasing 

trend, 2 showed an increasing trend, and 19 showed no 

trend (fig. 16, table 5). The decreasing trends are generally 

attributed to lack of recent disposal and to radioactive decay. 

Wells with no trend generally had concentrations less than 

the reporting level (tables 5 and 6, at back of report). The 

two perched groundwater wells that showed an increasing 

trend (TRA A77 and USGS 55) are near the radioactive-waste 

infiltration ponds at the ATR complex (fig. 16), and could 

be influenced by strontium-90 that was discharged to those 

ponds before they were replaced by lined evaporation ponds 

in 1993. The strontium-90 concentrations detected in these 

two perched groundwater wells also could be attributed to 

exchange reactions whereby strontium-90 sorbed to sediment 

is remobilized into solution in the unsaturated zone beneath 

the radioactive-waste infiltration ponds. 

Cesium-137

The radionuclide cesium-137 is a product of nuclear 

weapons tests and is present in wastewater discharged at 

several facilities at the INL. Cesium-137 has a half-life of 

30.17 years (Walker and others, 1989). The number of samples 

collected and the number of samples with concentrations 

greater than the reporting level are shown in table 6. Because 

concentrations for most samples were less than the reporting 

level (table 6), no trend analyses were done. 

Plutonium

In 1974, the USGS began monitoring for plutonium-238 

and plutonium-239, -240 (undivided) in water from 

selected wells near TAN, INTEC, and RWMC, because of 

waste disposal practices. The half-lives of plutonium-238, 

plutonium-239, and plutonium-240 are 87.7, 24,100, and 

6,560 years, respectively (Walker and others, 1989, p. 46). 

The number of samples collected and the number of samples 

with concentrations greater than the reporting level are shown 

in table 6. Because plutonium-238 and plutonium-239, -240 

(undivided) concentrations were less than the reporting levels 

for most samples, no trend analyses were done. 
Water-Quality Characteristics and Trends 21

tac14-0956_fig08

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 9 and 10 

See figures 9 and 10

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

105 108 

104 

RWMC M14S 

Rifle 

Range 

RWMC

M13S 

RWMC

M12S RWMC M11S 

106 127 

CFA 2 CFA 1 

Color of identifier is indicator of temperature measurement 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

CFA 1 

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information

MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 8. Areal distribution of temperature trends in water from selected aquifer wells at and near the Idaho National 

Laboratory, Idaho.
22 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig09

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation

ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

39 

34 

36 

37 

38 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

RWMC M1SA 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

77

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43°

30’

43°

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Color of identifier is indicator of temperature measurement 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

Figure 9. Areal distribution of temperature trends in water from selected aquifer wells at the 

Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 23

tac14-0956_fig10

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 6

PW 7

PW 1

PW 3

PW 4

PW 2

PW 5

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 FEET

1,000 METERS

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 2

CWP 4

CWP 5

TRA A13

TRA A77

Color of identifier is indicator of temperature measurement 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

Figure 10. Areal distribution of temperature trends in water from selected perched groundwater wells at the Advanced 

Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste Management 

Complex, Idaho National Laboratory, Idaho.
24 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig11

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 12 and 13 

See figures 12 and 13

ATRC

INTEC

MFC

NRF

TAN

RWMC

PBF

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

108 105 

104 

RWMC M14S 

Rifle 

Range 

RWMC

M13S 

RWMC

M12S 

RWMC M11S 

106 127 

CFA 1 CFA 2 

124 

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network 

and identifier

Local well identifier—Number indicates only

USGS well; other names are local well names. 

See table 2 for more information MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Color of identifier is indicator of tritium trend; green

indicates decreasing trend; black indicates no trend. 

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 11. Areal distribution of tritium trends in water from selected aquifer wells at and near the Idaho National Laboratory, 

Idaho.
Water-Quality Characteristics and Trends 25

tac14-0956_fig12

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation

ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 

37 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43°

30’

43°

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Color of identifier is indicator of tritium trend; green

indicates decreasing trend; red color indicates an 

increasing trend; black indicates no trend. 

Figure 12. Areal distribution of tritium trends in water from selected aquifer wells at the Advanced 

Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, Idaho National Laboratory, Idaho.
26 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig13

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 6

PW 1

PW 3

PW 4

PW 2

PW 5

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 FEET

1,000 METERS

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 4

CWP 5

TRA A13

TRA A77

Color of identifier is indicator of tritium trend; red color 

indicates increasing trend; green indicates decreasing 

trend; black indicates no trend.

Figure 13. Areal distribution of tritium trends in water from selected perched groundwater wells at the Advanced Test 

Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste Management Complex, 

Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 27

tac14-0956_fig14

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 15 and 16 

See figures 15 and 16

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

Rifle 

Range 

127 

CFA 1 

CFA 1 

CFA 2 

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information

MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Color of well identifier is indicator of strontium-90 trend;

black indicates no trend.

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 14. Areal distribution of strontium-90 trends in water from selected aquifer wells at and near the Idaho National 

Laboratory, Idaho.
28 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig15

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation

ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

65 

76 

58 

39 

35 

34 

36 

37 

38 

37 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43 ̊

30’

43 ̊

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Color of identifier is indicator of strontium-90 trend; green

indicates decreasing trend; black indicates no trend.

Figure 15. Areal distribution of strontium-90 trends in water from selected aquifer wells at the 

Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 29

tac14-0956_fig16

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 6

PW 1

PW 3

PW 4

PW 2

PW 5

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 FEET

1,000 METERS

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 4

TRA A13

TRA A 77

Color of identifier is indicator of strontium-90 trend; 

red color indicates increasing trend; green indicates 

decreasing trend; black indicates no trend.

Figure 16. Areal distribution of strontium-90 trends in water from selected perched groundwater wells at the Advanced 

Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste Management 

Complex, Idaho National Laboratory, Idaho.
30 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Americium-241

Americium-241 is a decay product of plutonium-241. 

Plutonium isotopes have been detected in wastewater 

discharged to the ESRP aquifer at the INL and in waste buried 

at the RWMC. The half-life of americium-241 is 432.7 years 

(Walker and others, 1989, p. 46). Water from 16 aquifer wells 

and 1 perched groundwater well were routinely sampled and 

analyzed for plutonium isotopes. The number of samples 

collected and the number of samples with concentrations 

greater than the reporting level are shown in table 6. Because 

americium-241 concentrations were less than the reporting 

levels for most samples, no trend analyses were done. 

Gross Alpha- and Beta-Particle Radioactivity

Gross alpha- and beta-particle radioactivity is a measure 

of the total radioactivity emitted as alpha and beta particles 

during the radioactive decay process. The radioactivity usually 

is reported as if it occurred as one radionuclide. Gross alpha 

and beta measurements are used to screen for radioactivity 

in the aquifer as a possible indicator of groundwater 

contamination, but measurable concentrations also can occur 

from the natural decay of radioactive material in aquifer 

material. In 2008, the RESL increased the sensitivity of the 

analyses; therefore, concentrations greater than the reporting 

level for natural background concentrations in the aquifer were 

sometimes measured, although those same concentrations may 

not have been reported in the past. 

Water samples have been routinely collected and 

analyzed for gross alpha- and beta-particle activity from 

16 aquifer wells and 2 perched groundwater wells used in 

this study. The number of samples collected and the number 

of samples with concentrations greater than the reporting 

level are shown in table 6. Because gross alpha- and betaparticle activity are less than the reporting levels for most 

of the samples, no statistical trend analyses were done. 

Concentrations for a few of the samples were equal to or 

greater than the reporting level. Some of the samples with 

results at reporting levels of 3s could be due to statistical 

fluctuations because the counting data are close to background 

concentrations. Other concentrations may represent 

background concentrations in the aquifer that have been 

detected because of increased sensitivity of the analyses, and 

some may be false positives (Davis, 2010, p. 28).

Chloride

Chloride has been discharged in wastewater at INL 

facilities since they were established. The background 

chloride concentration in water from the ESRP aquifer at 

the INL generally is about 15 mg/L (Robertson and others, 

1974, p. 150). The secondary maximum contaminant level 

(MCL) for chloride in drinking water is 250 mg/L (U.S. 

Environmental Protection Agency, 2013). Samples were 

routinely collected and analyzed for chloride from 63 aquifer 

wells and 33 perched groundwater wells used in this study. One 

aquifer well, RWMC M1SA, was not sampled for chloride. 

Two of the perched groundwater wells (CWP 5 and PW 7) had 

insufficient data to determine trends. Summary statistics and 

trends for chloride are given in table 7 (at back of report).

Chloride analyses were done by various laboratories 

until 1989, and most analyses since 1989 have been done at 

the NWQL. The datasets include some outlier values, and if 

the value did not seem reasonable compared with the specific 

conductance of the well, the outlier value was not used in the 

trend analysis. Chloride trends in water from aquifer wells at 

the INL are shown in figures 17 and 18.

Of the 63 aquifer wells analyzed for statistically 

significant chloride concentration trends, 31 of these wells 

had a decreasing trend, 15 had an increasing trend, and 17 

had no trend (table 7). Most wells near the INTEC and ATR 

Complex showed decreasing or no trends for chloride (fig. 18), 

probably the result of decreased disposal of wastewater and 

(or) discontinued use of the percolation ponds south of the 

INTEC and redirection of discharge to the new percolation 

ponds 2 mi southwest of the INTEC in 2002. Five aquifer 

wells south and southeast of the INTEC showed increasing 

chloride trends. Near the RWMC, most wells north of the 

facility showed increasing chloride trends (figs. 17 and 18). The 

statistically significant increasing trends in the wells southeast 

of INTEC are attributed to lower transmissivity for the part 

of the aquifer the wells sample. The lower transmissivity and 

subsequent slower movement of water may be an indication 

that wastewater from higher concentration disposal periods 

are still moving into the wells causing the concentrations to 

still be rising. The increasing concentrations of chloride in the 

RWMC area may be the result of chloride in wastes buried at 

RWMC moving into the aquifer, or from chloride in wastewater 

disposed at upgradient facilities finally reaching these wells. 

Perched groundwater analyzed for statistically significant 

trends in chloride concentration showed that 11 perched 

groundwater wells had decreasing trends, 4 had increasing 

chloride concentration trends, and 18 had no trend (table 7). 

Most of the wells around the INTEC showed decreasing trends 

(fig. 19) and the trends are attributed to changes in disposal. 

Two of the wells (USGS 73 and PW 9) with increasing trends 

are in close proximity to each other and sample water from the 

same deep perched water zone, just south of the ATR Complex 

(fig. 19). Samples collected from the other two wells showed 

increasing trends (TRA A13 and A77) from a shallow perched 

zone. Chloride concentration trends generally were similar to 

the trend in specific conductance (appendixes B and D).

Chloride (along with sodium, sulfate, and some 

nitrate) concentrations in wells USGS 34–39 and USGS 

112–113 may have been influenced by episodic recharge 

from the Big Lost River. Chloride, sodium, and sulfate 

concentrations seem to be inversely correlated with an increase 

in groundwater levels for wells USGS 35 and 39 (fig. 20).
Water-Quality Characteristics and Trends 31

tac14-0956_fig17

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 18 and 19 

See figures 18 and 19

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

108 105 

104 

RWMC M14S 

Rifle 

Range 

RWMC

M13S 

RWMC

M12S 

RWMC M11S 

106 127 

CFA 2 CFA 1 

Color of identifier is indicator of chloride concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

 CFA 1

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 17. Areal distribution of chloride concentration trends in water from selected aquifer wells at and near the Idaho 

National Laboratory, Idaho.
32 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig18

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation

ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 

44 

45 

46 

47 

48 84 

TRA

Disposal

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Color of identifier is indicator of chloride concentration 

trend; red color indicates increasing trend; green

indicates decreasing trend; and black indicates no 

trend

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43 ̊

30’

43 ̊

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Figure 18. Areal distribution of chloride concentration trends in water from selected aquifer wells 

at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 33

tac14-0956_fig19

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

TRA A 77

PW 6

PW 1

PW 3

PW 4

PW 2

PW 5

Color of identifier is indicator of chloride concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

 92

Radioactive Waste

Management Complex

Subsurface

Disposal 

Area Transuranic

Storage

Area

113°03’ 113°02’30”

43°

30’

43°

29’

30”

0

0

3,000 FEET

1,000 METERS

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

CWP 2

CWP 4

TRA A13

Figure 19. Areal distribution of chloride concentration trends in water from selected perched groundwater wells at 

the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, Idaho National Laboratory, Idaho.
34 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig 20ab

Depth

Chloride

Sodium

Sulfate

EXPLANATION

10

0

20

30

40

50

Concentration, in milligrams per liter

A. USGS 35 (433339112565801) 465

467

469

471

473

475

477

479

481

483

485

10

0

20

30

40

50

60

70

198919901991199219931994

199519951995199519952000200120022003200420052006200720082009201020112012

2013

B. USGS 39 (433343112570001) 465

470

475

480

485

490

Depth to water, in feet below land surface

Year

Figure 20. Fluctuations in chloride, sodium, and sulfate concentrations relative to water-level changes at wells 

(A) USGS 35 and (B) USGS 39 and (C) changes in streamflow from the Big Lost River, Idaho.
Water-Quality Characteristics and Trends 35

tac14-0956_fig20cd

Big

Lost

Big Lost River below

Mackay Reservoir,

near Mackay, Idaho

13127000

Mackay

Reservoir

Spreading

areas

13132513

INL diversion at head,

near Arco, Idaho 

13132520

Idaho National

Laboratory

Arco

Mackay

River

Big Lost River below

INL diversion,

near Arco, Idaho

Streamflow, in thousands of acre-feet per water year

100

200

300

400

500

0

Partial water year

97-year average:

218,900 acre-feet per year

1970 1980 1990 2000 2010

00000 0 0

Streamflow, in thousands of acre-feet per water year

0

100

200

300

400

0 000

2.0 2.3

0

Water year

1904 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Water year

D

EXPLANATION

13132513 INL diversion at 

head, near Arco, Idaho

13132520 Big Lost River below 

INL diversion, near Arco, 

Idaho

Total streamflow upstream of diversion

C. Station 13127000, Big Lost River below Mackay Reservoir, near Mackay, Idaho

EXPLANATION

Figure 20.—Continued
36 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

 Wells USGS 34, 36, 38, and USGS 112–113 show similar 

patterns with concentrations decreasing during wet periods 

when there is more recharge from the Big Lost River and 

thus increasing groundwater levels, and increasing during dry 

periods, when there is no recharge from the Big Lost River 

(fig. 20). Although groundwater levels visually appear to 

have some effect, when using water level as a covariant in the 

statistical model, no significant effect on trend occurs (table 3). 

Sodium

Sodium has been discharged in wastewater at INL 

facilities since they were established. The background 

concentration of sodium in water from the ESRP aquifer near 

the INL generally is less than 10 mg/L (Robertson and others, 

1974, p. 155). Samples were routinely collected and analyzed 

for sodium from 59 aquifer wells and 24 perched groundwater 

wells. Aquifer well CFA LF 3-9 was not analyzed for sodium, 

and wells RWMC M1SA, RWMC M3S, RWMC M7S, and 

USGS 128 had only one analysis each for sodium. Perched 

groundwater wells USGS 92, CWP 1, 2, 3, 5, and 8 were not 

analyzed for sodium, and wells CWP 4, PW 6, PW 7, TRA 

A 13, and TRA A 77 had insufficient data for trend analyses. 

Summary statistics and trends are given in table 7.

Sodium analyses were done by various laboratories until 

1989 and most analyses since have been done at the NWQL. 

The datasets included some outlier values, and if the value did 

not seem reasonable compared with the specific conductance, 

the outlier value was not used in the trend analyses. Only 

analyses by the NWQL for 1989–2012 are included in the 

trend analyses. Sodium trends in water from aquifer wells and 

perched groundwater wells at the INL are shown in figures 21, 

22, and 23.

Of the 59 aquifer wells analyzed for statistically 

significant sodium concentration trends, 22 wells showed 

a decreasing trend, 14 showed an increasing trend, and 

23 showed no trend (figs. 21 and 22, table 7). Sodium hydrate 

was a predominant constituent in wastewater discharged to 

the chemical-waste infiltration pond at the ATR Complex 

(Davis, 2010). South and east of the ATR Complex, sodium 

showed increasing trends in a few wells (fig. 22). Sodium and 

chloride were two of the predominant chemical constituents 

in wastewater discharged at the INTEC (Pittman and others, 

1988; Orr and Cecil, 1991; Bartholomay and others, 2000). 

South of the INTEC, trends in sodium generally were similar 

to trends in chloride, with the exception of well USGS 39, 

which had an increased sodium trend and no chloride trend. 

Some of the water from wells showing decreasing trends in 

chloride showed no trends in sodium at the INTEC (figs. 18

and 22). Sodium and chloride were predominant constituents 

discharged in wastewater at the Central Facilities Area (CFA) 

(Bartholomay and others, 2000). Some wells downgradient of 

the CFA and near the southern boundary of the INL showed 

increasing trends in sodium, whereas there was no trend in 

chloride (figs. 17 and 21). The increasing trend for sodium 

could be due to the long-term disposal of wastewater at 

upgradient facilities. The lack of trend for chloride could be 

because it is more mobile in groundwater (Hem, 1989, p. 118) 

than sodium and, thus, more dispersed in the aquifer system. 

The increasing sodium trend in the Rifle Range well is likely 

the result of the redirection of discharge from the INTEC to 

the new percolation ponds 2 mi southwest of the INTEC. Five 

perched groundwater wells analyzed for sodium trends had 

decreasing trends, 1 (USGS 71) had an increasing trend, and 

18 had no trend (fig. 23, table 7).

Fluoride

Fluoride was discharged in wastewater to percolation 

ponds at the INTEC during 1971–98 (Bartholomay and others, 

2000). Background concentrations of fluoride in the ESRP 

aquifer in the southwestern part of the INL range from about 

0.1 to 0.3 mg/L (Robertson and others, 1974, p. 75). The MCL 

for fluoride in drinking water is 4 mg/L (U.S. Environmental 

Protection Agency, 2013). Samples were routinely collected 

and analyzed for fluoride from four wells used in this study. 

Summary statistics and trends calculated are given in table 7.

Fluoride concentration trends for four aquifer wells 

(CPP 1, USGS 34, 38, and 77) near the INTEC are shown 

in table 7. Other aquifer and perched groundwater wells 

were sampled sporadically for fluoride; however, data from 

those wells were not sufficient to determine statistically 

significant trends. For the four aquifer wells with sufficient 

data, two (USGS 38 and USGS 77) showed increasing 

trends and two (CPP 1 and USGS 34) showed no trend. All 

fluoride concentrations were within the background range of 

0.1 to 0.3 mg/L, indicating that wastewater disposal has not 

had an appreciable effect on fluoride concentrations in the 

ESRP aquifer near the INTEC (Davis and others, 2013). The 

increasing trends probably are due to changes in the reporting 

standards by the NWQL and not the result of actual changes in 

the concentrations of fluoride in the aquifer. 

Sulfate

Sulfate has been discharged in wastewater at the INL 

facilities since they were established. The background sulfate 

concentrations in water from the ESRP aquifer in the southcentral part of the INL range from about 10 to 40 mg/L 

(Robertson and others, 1974, p. 72). The secondary MCL for 

sulfate in drinking water is 250 mg/L (U.S. Environmental 

Protection Agency, 2013). Sulfate was routinely analyzed 

for water samples from 48 aquifer wells and 22 perched 

groundwater wells used in this study. 
Water-Quality Characteristics and Trends 37

tac14-0956_fig21

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 22 and 23 

See figures 22 and 23

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

108 105 

104 

RWMC M14S 

Rifle 

Range 

RWMC

M13S 

RWMC

M12S 

RWMC M11S 

106 127 

CFA 2 CFA 1 

Color of identifier is indicator of sodium concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

CFA 1 

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information

MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 21. Areal distribution of sodium concentration trends in water from selected aquifer wells at and near the Idaho 

National Laboratory, Idaho.
38 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig22

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation ponds Big

Lost

River

Spreading area

89 

87 RWMC

Production

88 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 

112 113 

85 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 44 

45 

46 

47 

48 84 

TRA 

Disposal

CPP 1 

40 

120 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Color of identifier is indicator of sodium concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43°

30’

43°

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Figure 22. Areal distribution of sodium concentration trends in water from selected aquifer wells 

at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 39

tac14-0956_fig23

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

56 55

 60

 53

61

 71

PW 1

PW 3

PW 4

PW 2

PW 5

Color of identifier is indicator of sodium concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

EXPLANATION

PW 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

LINCOLN BOULEVARD

 54

Figure 23. Areal distribution of sodium concentration trends in water from selected perched groundwater wells at 

the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, Idaho National Laboratory, Idaho.
40 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Sulfate analyses were done by various laboratories until 

1989, and most analyses since then have been done at the 

NWQL. The datasets include some outlier values, and if the 

value did not seem reasonable compared with the specific 

conductance of the well, the outlier value was not used in 

the trend analyses. Sulfate trends and summary statistics for 

water from sites at the INL from 1989 to 2012 are shown in 

figures 24–26, table 7, and appendix D.

Forty-eight aquifer wells were analyzed for statistically 

significant sulfate concentration trends; 24 had decreasing 

trends, 13 had increasing trends, and 11 had no trend. 

Most aquifer wells that had increasing trends were located 

downgradient of the INTEC or ATR Complex, in the general 

direction of regional groundwater flow toward the southwest. 

The increasing trend in these wells may be attributable to 

disposal of sulfate-enriched wastewater at the ATR Complex 

cold and chemical waste ponds. As with chloride and sodium, 

some wells appear to be affected by episodic recharge from 

the Big Lost River, which dilutes sulfate concentrations in 

the groundwater (fig. 20). Closer to the facilities, sulfate 

trends either decreased or there was no trend (figs. 24 and 25, 

table 7). Most perched groundwater wells near the INTEC 

and ATR Complex showed decreasing or no trends, with the 

exception of well PW 4, east of the percolation ponds at the 

INTEC, which showed an increasing trend (fig. 26).

Nitrite Plus Nitrate (as N)

Wastewater containing nitrate was injected into the 

ESRP aquifer through the INTEC disposal well from 1952 to 

February 1984, and was discharged to the INTEC percolation 

ponds after February 1984 (Orr and Cecil, 1991). Because 

nitrite analyses indicate that almost all nitrite plus nitrate 

concentrations are nitrate (as N), concentrations will be 

referred to as nitrate in this report. Background concentrations 

of nitrate in groundwater not affected by wastewater disposal 

from INL facilities generally are less than 1 mg/L (Robertson 

and others, 1974, p. 73). The MCL for nitrate in drinking 

water is 10 mg/L (U.S. Environmental Protection Agency, 

2013). Nitrate was routinely analyzed for water samples from 

59 aquifer wells and 1 perched groundwater well. Nitrate 

trends and summary statistics for water from wells at the 

INL for 1989–2012 are shown in figures 27–28, table 7, 

and appendix D.

Fifty-nine aquifer wells were analyzed for trends in 

nitrate concentrations. Of those, 28 showed a decreasing trend, 

8 showed an increasing trend, and 23 showed no trend (figs. 27

and 28). As was shown for chloride, sodium, and sulfate 

for wells near the Big Lost River, the nitrate concentrations 

decreased during periods when water levels were higher, 

probably due to recharge and dilution from Big Lost River 

seepage, and increased when recharge from Big Lost seepage 

was less (Bartholomay and others, 2012) (appendix D). 

Most of the wells around INTEC showed decreasing or 

no trend, which probably is due to discontinued use of the 

disposal well in 1984 and the percolation ponds in 2002. The 

increasing concentration in USGS 67 (fig. 28) is puzzling 

and may indicate another source of contamination rather than 

the percolation ponds. Only one perched groundwater well 

(USGS 50) was analyzed for a trend in nitrate. Results for this 

well indicated a decreasing trend (table 7) which probably was 

due to discontinued use of the INTEC disposal well in 1984.

Orthophosphate (as P)

Orthophosphate (as P) has not been a major constituent 

discharged in wastewater at the INL; only about 9 kg was 

discharged in liquid effluent at the INL from 1971 to 1998 

(French and others, 1999). Water samples from 59 aquifer 

wells and 1 perched groundwater well were routinely analyzed 

for orthophosphate (as P). Summary statistics and trends for 

orthophosphate (as P) are given in table 7.

Orthophosphate (as P) concentrations were near or less 

than the reporting levels for most of the samples in most of 

the wells. Of the 59 aquifer wells analyzed for statistically 

significant orthophosphate concentration trends, 26 had 

increasing trends and 33 had no trend. The increasing trends 

could be due to anthropogenic influence from activities 

upgradient of the INL or could be due to changes in data 

reporting by the NWQL rather than actual changes in 

concentrations in the aquifer. Prior to 2003, results were 

rounded to the nearest tenth and since 2003, results are 

rounded to the nearest hundredth of a milligram per liter. The 

only perched aquifer well analyzed for an orthophosphate 

trend at the INTEC was USGS 50; results indicated no 

trend (table 7). 

Trace Elements

A suite of trace elements including aluminum, antimony, 

arsenic, barium, beryllium, cadmium, cobalt, copper, lead, 

manganese, molybdenum, nickel, silver, uranium, and zinc 

were routinely collected from two wells (USGS 65 and 

USGS 84). Water samples were analyzed for chromium from 

25 aquifer wells and 21 perched groundwater wells. Samples 

for selenium analysis were collected from wells USGS 65 

and USGS 84 downgradient of the ATR Complex. Selenium 

was considered a constituent of concern in the 1993 INL 

groundwater-monitoring plan at that facility (Sehlke and 

Bickford, 1993). Neither well had sufficient data for statistical 

analysis of beryllium and silver.

Results of trend tests for trace element concentrations 

are shown in appendix D. Summary statistics and trend 

test results are given in table 7. Well USGS 65 showed a 

decreasing trend for barium, cadmium, cobalt, lead, and zinc, 

increasing trends for arsenic, molybdenum, and uranium, and 

no trend for aluminum, antimony, copper, manganese, nickel, 

and selenium. Well USGS 84 showed decreasing trends for 

cadmium, cobalt, copper, lead, nickel, and zinc, an increasing 

trend for arsenic, and no trend for aluminum, antimony, 

barium, manganese, molybdenum, selenium and uranium. 
Water-Quality Characteristics and Trends 41

tac14-0956_fig24

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 25 and 26 

See figures 25 and 26

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

Rifle 

Range 

CFA 1 

CFA 1 

CFA 2 

Color of identifier is indicator of sulfate concentration 

trend; red color indicates increasing trend; and green

indicates decreasing trend

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 24. Areal distribution of sulfate concentration trends in water from selected wells at and near the Idaho National 

Laboratory, Idaho.
42 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig25

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation ponds Big

Lost

River

Spreading area

87 RWMC

Production

88 

120 

MTR TEST 

65 

79 

76 

58 

39 

35 

34 

36 

37 

38 

112 113 

85 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 

44 

45 

46 

47 

48 84 

TRA

Disposal

CPP 1 

40 

Color of identifier is indicator of sulfate concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

89 

EXPLANATION

CPP 1

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43°

30’

43°

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Figure 25. Areal distribution of sulfate concentration trends in water from selected aquifer wells 

at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the 

Radioactive Waste Management Complex, Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 43

tac14-0956_fig26

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste ponds

Cold-waste ponds

INTEC

DISPOSAL

WELL

Idaho Nuclear

Technology and

Engineering Center

Advanced Test Reactor Complex

Percolation ponds

Tank farm

(approximately

located) Big

Lost

River

PW 9

PW 8

 78

 73

72

 70

 69

 68

 66

 50

 63 

 62

 55

 60

61

 71

PW 4

PW 2

Color of identifier is indicator of sulfate concentration 

trend; red color indicates increasing trend; green indicates 

decreasing trend; and black indicates no trend

EXPLANATION

CWP 1

Well in the U.S. Geological Survey perched 

groundwater-quality monitoring network and 

identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

0

0

3,000 FEET

1,000 METERS

43°

35’

43°

34’

112°58’ 112°56’

Idaho 

National 

Laboratory

Map areas

LINCOLN BOULEVARD

CWP 8

CWP 3

CWP 1

 54

Figure 26. Areal distribution of sulfate concentration trends in water from selected perched groundwater wells at 

the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and the Radioactive Waste 

Management Complex, Idaho National Laboratory, Idaho.
44 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

tac14-0956_fig27

Big 

Southern

Butte

East

Butte

Middle

Butte

BITTERROOT

RANGE

LEMHI RANGE

LOST RIVER RANGE

33

26

26

20

20

See figures 28 and 29 

See figures 28 and 29

ATR Complex

INTEC

MFC

PBF

NRF

TAN

RWMC

IDAHO NATIONAL 

LABORATORY BOUNDARY

Mud

Lake

Big

Lost

River

Little

Lost River

Birch

Creek

Camas

Creek

Atomic

City

Howe

Arco

Mud

Lake Terreton

Big Lost River

playas and 

sinks

SPREADING

AREAS

124 

105 108 

104 

RWMC M14S 

RWMC

M13S 

RWMC

M12S 

RWMC M11S 

127 

CFA 1 

CFA 1 

CFA 2 

Color of identifier is indicator of nitrate plus nitrite (as N) 

concentration trend; red color indicates increasing trend; 

green indicates decreasing trend; and black indicates no 

trend

Well in the U.S. Geological Survey aquifer 

water-quality monitoring network and 

identifier

Local well identifier—Number indicates only USGS 

well; other names are local well names. See table 2 

for more information MFC—Materials and Fuels Complex 

CFA—Central Facilities Area

INTEC—Idaho Nuclear Technology and Engineering Center

NRF—Naval Reactors Facility

RWMC—Radioactive Waste Management Complex

TAN—Test Area North

PBF—Power Burst Facility

EXPLANATION

Selected facilities at the Idaho National Laboratory

ATR Complex—Advanced Test Reactor Complex—formerly known as

Reactor Technology Complex (RTC) and Test Reactor

Area (TRA)

Boundary of Idaho National Laboratory

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

113°15’ 113°00’ 45’

44°

00’

43°

30’

45’

112°30’ 112°15’

0 5 10 MILES

0 5 10 KILOMETERS

IDAHO

BOISE

Eastern 

Snake River

Idaho Plain

National

Laboratory

Twin

Falls

Pocatello

Idaho

Falls

Figure 27. Areal distribution of nitrite plus nitrate (as N) concentration trends in water from selected wells at and near the 

Idaho National Laboratory, Idaho.
Water-Quality Characteristics and Trends 45

tac14-0956_fig28

Color of identifier is indicator of nitrate plus nitrite (as N) 

concentration trend; red color indicates increasing trend; 

green indicates decreasing trend; and black indicates no 

trend

33

LINCOLN BOULEVARD

Transuranic

storage

area

Subsurface

disposal area

Radioactive Waste 

Management Complex

Advanced Test

Reactor Complex

Idaho Nuclear

Technology and

Engineering Center

Chemical-waste pond

Sanitary-waste pond

Evaporation ponds

Radioactive-waste

ponds

Cold-waste ponds

Percolation ponds Big

Lost

River

Spreading area

89 

87 

RWMC M3S 

RWMC M7S 

RWMC

Production

88 

120 

MTR TEST 

65 

76 

39 

35 

34 

36 

37 

38 

112 113 

85 

128 

CFA LF 2-10 

77 

111 

57 

82 

67 

116 

115 

20 

114 

51 

123 

52 

59 

CPP 2 

41 

42 

43 

44 

45 

46 

47 

48 84 

TRA

Disposal

CPP 1 

CPP 1 

CFA LF 3-9 

40 

EXPLANATION

Well in the U.S. Geological Survey 

aquifer water-quality monitoring 

network and identifier

Local well identifier—Number 

indicates only USGS well, other 

names are local well names

Base from U.S. Geological Survey digital data, 1:24,000 and 1:100,000

Universal Transverse Mercator projection, Zone 12

Datum is North American Datum of 1927

Idaho 

National 

Laboratory

Map areas

0 1,000 METERS

0 3,000 FEET

0

0 3,000 FEET

1,000 METERS

113 ̊03’

43°

30’

43°

29’

113 ̊02’

112°58' 57' 56' 55' 112°54'

43°

35'

34'

43°

33'

Figure 28. Areal distribution of nitrite plus nitrate (as N) concentration trends in water from 

selected aquifer wells at the Advanced Test Reactor Complex, Idaho Nuclear Technology and 

Engineering Center, and the Radioactive Waste Management Complex, Idaho National Laboratory, 

Idaho.
46 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Chromium

Disposal of chromium in wastewater has occurred at the 

ATR Complex, INTEC, and the Power Burst Facility (PBF) 

(Davis, 2010, p. 37). Background concentrations of chromium 

in water from the ESRP aquifer at the INL range from 2 to 

3 μg/L (Orr and others, 1991, p. 41). The MCL for chromium 

in drinking water is 100 μg/L (U.S. Environmental Protection 

Agency, 2013). Water samples were routinely collected 

and analyzed for chromium from 25 aquifer wells and 

21 perched groundwater wells. Summary statistics and trend 

test results for chromium concentrations are shown in table 7

and appendix D.

Of the 25 aquifer wells analyzed for statistically 

significant chromium concentration trends, 8 showed 

decreasing trends, 3 showed increasing trends, and 14 showed 

no trend. The three wells that showed increasing trends 

(CPP 1, USGS 34, and USGS 38) are located at or just 

downgradient of the INTEC. One well downgradient of the 

ATR Complex (USGS 65) showed a decreasing trend. Most 

of the other wells showing decreasing trends (Rifle Range 

Well, CFA LF- 2-10, RWMC M12S, RWMC M14S, USGS 77, 

USGS 87, and USGS 127) are near the CFA and the RWMC.

Of the 21 perched groundwater wells analyzed for 

chromium, 13 showed a decreasing trend, 1 well (USGS 

68, at the ATR Complex) showed an increasing trend, and 

7 showed no trend. All of the perched groundwater wells 

showing decreasing trends (CWP 3, PW 8-9, USGS 54-55, 

USGS 60-63, USGS 70-71, USGS 73, and USGS 78) are 

south or southeast of the ATR Complex. Decreasing trends 

in chromium concentrations in this area probably are due to 

discontinued disposal at the ATR complex.

Total Organic Carbon

Total organic carbon (TOC) is used as a general 

indicator of groundwater contamination and as a screen for 

other organic compounds in the aquifer. As part of the INL 

groundwater-monitoring program adopted in 1994, the USGS 

began collecting and analyzing water from several wells at 

the INL for TOC. Water samples were routinely analyzed for 

TOC from 15 aquifer wells but no water samples from perched 

groundwater wells were analyzed. Summary statistics and 

trend test results for TOC concentrations are shown in table 7

and appendix D. Four wells near the RWMC (RWMC M11S, 

RWMC M12S, RWMC M13S, and RWMC M14S) showed 

decreasing trends for TOC; no wells showed increasing trends, 

and 11 wells had no trend.

Volatile Organic Compounds

Volatile organic compounds (VOCs) are present in water 

from the ESRP aquifer because of historical waste-disposal 

practices at the INL. The VOCs were used for degreasing, 

decontamination, and other activities at INL facilities (Mann 

and Knobel, 1987, p. 1). An estimated 88,400 gal of organic 

waste was buried before 1970 in the SDA at the RWMC 

(Mann and Knobel, 1987, p. 1). These buried organic wastes 

included about 24,400 gal of carbon tetrachloride; 39,000 gal 

of lubricating oil; and about 25,000 gal of other organic 

compounds, including trichloroethane, trichloroethylene, 

perchloroethylene, toluene, and benzene. VOC concentrations 

for nine aquifer wells were analyzed for trends. At 

other aquifer wells, data were not sufficient to evaluate 

concentration trends, or the concentrations were all less than 

the reporting level. Concentration trends in aquifer wells 

with VOC data are given in table 8 (at back of report) and 

appendix E. 

Historically, concentrations of VOCs in water samples 

from several wells at and near the RWMC exceeded the 

reporting levels (Bartholomay and others, 2000). However, 

concentrations for all VOCs except carbon tetrachloride were 

less than the MCL for drinking water (U.S. Environmental 

Protection Agency, 2013). Trend test results for carbon 

tetrachloride concentrations in water from the RWMC 

Production Well (appendix E) indicate a statistically 

significant increase in concentrations has occurred since 

1987 (table 8 and appendix E). Concentrations have routinely 

exceeded the MCL for carbon tetrachloride in drinking water 

(5 μg/L) since 1998. 

Davis and others (2013) indicated that more recent 

data collected since 2005 may be showing indications that 

concentrations are leveling off in the RWMC Production 

well. To further test this statement, a trend analyses was run 

on the dataset from 2005 through 2012 (fig. 29). The trend 

test on that dataset had a p-value of 0.054, and still shows a 

positive increase, but the trend is not considered significant 

using the criteria for this report. The lack of a more recent 

significant increasing trend may indicate that engineering 

practices designed to reduce VOC concentration movement 

to the aquifer are having a positive effect. The RWMC 

Production well also had increasing trends for trichloroethene, 

trichloromethane, tetrachloroethene, 1,1,1-trichloroethane, 

and tribromomethane (table 7, appendix E). During 2009–11, 

water from well USGS 87, just north of the RWMC (fig. 3), 

had detectable concentrations of carbon tetrachloride, 

and exceeded the MCL for the first time in 2011 (Davis 

and others, 2013). Concentrations of carbon tetrachloride 

from this well have had an increasing trend since 1987 

(table 8, appendix E). Well USGS 87 also had increasing 

concentration trends for trichloroethene, trichloromethane, 

dichlorodifluoromethane, but not a significant trend for 

1,1,1-trichloroethane and tetrachloroethene. Well USGS 120, 

south of the RWMC (fig. 3), had increasing concentration 

trends of carbon tetrachloride and trichloromethane and no 

significant trends for tetrachloroethene, 1,1,1-trichloroethane, 

and trichloroethene (table 8, appendix E). Well USGS 88 

had decreasing concentration trends for carbon tetrachloride, 

trichloroethene, and 1,1,1-trichloroethane, and no 

significant trend for trichloromethane (table 8, appendix E). 
Factors Influencing Water-Quality Trends at Each Well 47

tac14-0956_fig29

RWMC Production (433002113021701)

Carbon tetrachloride, in micrograms per liter

2005 2006 2007 2008 2009 2010 2011 2012 2013

4

6

8

10

12

Regression, p = 0.054

Figure 29. Carbon tetrachloride trend from Radioactive Waste Management Complex Production well, Idaho National 

Laboratory, Idaho, 2005–12.

Wells near the INTEC and ATR Complex (USGS 34, 

USGS 38, USGS 65, and USGS 77) had decreasing 

trends for 1,1,1-trichloroethane. Well USGS 77 also had a 

decreasing trend for 1,1,-dichloroethene. Wells USGS 34, 

USGS 38, and USGS 65 had no significant trend for 

dichlorodifluoromethane, and wells USGS 77 and 84 had 

decreasing trends for dichlorodifluoromethane. All other 

VOCs in all of the wells not mentioned had concentrations less 

than their respective reporting levels.

Factors Influencing Water-Quality 

Trends at Each Well 

Chloride, chromium, nitrate, sodium, and sulfate are 

the primary non-radioactive constituents that have been 

discharged in wastewater at INL facilities. Additionally, 

elevated concentrations of these constituents in water samples 

also can come from other anthropogenic sources. Tritium and 

strontium-90 are the primary radioactive constituents that have 

been discharged in wastewater at INL facilities. Because of 

this, these are the primary constituents discussed for each well. 

Aquifer Wells near Idaho Nuclear Technology 

and Engineering Center

CPP-1.—Trend test results for this well indicate that 

chloride, nitrate, sulfate, and tritium concentrations show 

decreasing trends, chromium shows an increasing trend, and 

fluoride, sodium, and strontium-90 show no trend (tables 5

and 7). The decreasing trends are attributed to discontinued 

disposal of these constituents at the INTEC along with 

continued dilution and dispersion in the aquifer system, and to 

radioactive decay for tritium. 

CPP-2.—Chloride, nitrate, and sulfate concentrations 

show decreasing trends and sodium, strontium-90, and tritium 

show no trend (tables 5 and 7). The decreasing trends are 

attributed to discontinued disposal of these constituents at the 

INTEC along with continued dilution and dispersion in the 

aquifer system. 

Rifle Range well.—Sodium and chloride concentrations 

show an increasing trend, and chromium, sulfate, and tritium 

show a decreasing trend, and strontium-90 shows no trend 

(tables 5 and 7). The increases in sodium and chloride are 

related to waste disposal into the new INTEC percolation 

ponds upgradient of this well beginning in 2002. The 

decreasing trends are attributed to discontinued disposal of 

these constituents, continued dilution and dispersion in the 

aquifer system, and to radioactive decay for tritium.

USGS 20.—Chloride, sodium, and nitrate concentrations 

all show increasing trends, tritium shows a decreasing trend, 

and sulfate and strontium-90 show no trend (tables 5 and 7). 

The decreasing trend for tritium can probably be attributed to 

lack of recent wastewater disposal and to radioactive decay. 

The increasing trends of the other constituents are probably 

due to a mass of water from periods of higher wastewater 

disposal reaching this well and increasing the overall 

concentration in the aquifer over time.

USGS 34.—Chloride, sodium, 1,1,1,-trichloroethane, 

tritium, and strontium-90 concentrations all show decreasing 

trends, sulfate and chromium show increasing trends, and 

nitrate and fluoride show no trend (tables 5 and 7). The 

decreasing trends for sodium, chloride, 1,1,1,-trichloroethane, 

tritium, and strontium-90 probably can be attributed to lack 

of recent wastewater disposal, and to radioactive decay in 

the case of tritium and strontium-90. Sulfate and chromium 

increases could be the result of wastewater discharged at 

the ATR Complex finally reaching this well and causing 

concentrations to increase. Several of the constituents 
48 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

(especially sulfate) (appendix D) show fluctuating 

concentrations with rising and declining water levels, so 

dilution or lack of dilution from recharge also be may 

contributing to the concentration changes.

USGS 35.—Chloride, nitrate, sodium, and tritium 

concentrations show decreasing trends, sulfate shows an 

increasing trend, and strontium-90 shows no trend (tables 5

and 7). The decreasing trends for chloride, nitrate, and sodium 

and tritium can probably be attributed to lack of recent 

wastewater disposal and to radioactive decay in the case of 

tritium. Sulfate increases could be the result of wastewater 

discharged at the ATR Complex finally reaching this well and 

causing concentrations to increase. Several of the constituents 

(especially sulfate) (appendix D, fig. 20) show fluctuating 

concentrations with rising and declining water levels, so 

dilution or lack of dilution from recharge may also be 

contributing to the concentration changes.

USGS 36.—Chloride, nitrate, sodium, tritium, and 

strontium-90 concentrations all show decreasing trends, 

and sulfate shows an increasing trend (tables 5 and 7). The 

decreasing trends for sodium, chloride, nitrate, tritium, and 

strontium-90 probably can be attributed to lack of recent 

wastewater disposal and to radioactive decay in the case of 

tritium and strontium-90. Sulfate increases could be the result 

of wastewater discharged at the ATR Complex finally reaching 

this well and causing concentrations to increase.

USGS 37.—Chloride, sodium, nitrate, tritium, and 

strontium-90 concentrations all show decreasing trends, 

and sulfate shows an increasing trend (tables 5 and 7). 

The decreasing trends for sodium, chloride, tritium, and 

strontium-90 probably can be attributed to lack of recent 

wastewater disposal and to radioactive decay in the case of 

tritium and strontium-90. Sulfate increases could be the result 

of wastewater discharged at the ATR Complex finally reaching 

this well and causing concentrations to increase.

USGS 38.—Chloride, nitrate, sodium, 

1,1,1,-trichloroethane, tritium, and strontium-90 

concentrations all show decreasing trends, and chromium, 

fluoride, and sulfate show an increasing trend (tables 5, 

7, and 8). The decreasing trends for sodium, chloride, 

1,1,1,-trichloroethane, tritium, and strontium-90 probably 

can be attributed to lack of recent wastewater disposal and 

to radioactive decay in the case of tritium and strontium-90. 

Chromium and sulfate increases could be the result of 

wastewater discharged at the ATR Complex finally reaching 

this well and causing concentrations to increase.

USGS 39.—Tritium concentrations show a decreasing 

trend, sulfate and sodium show increasing trends, and 

chloride, nitrate and strontium-90 show no trend (tables 5 and 

7, appendixes C and D). This well is near the Big Lost River 

and concentrations of all the constituents seem to fluctuate 

opposite to increases and decreases with water levels in the 

aquifer (fig. 20). For example, all the concentrations were the 

lowest when the water level was at its highest around 2000. 

USGS 40.—Chloride, sulfate, tritium, and strontium-90 

concentrations all show decreasing trends, and nitrate and 

sodium show no trend (tables 5 and 7). The decreasing trends 

for chloride, sulfate, tritium, and strontium-90 probably can 

be attributed to lack of recent wastewater disposal and to 

radioactive decay in the case of tritium and strontium-90.

USGS 41.—Chloride, sulfate, tritium, and strontium-90 

concentrations all show decreasing trends, and nitrate and 

sodium show no trend (tables 5 and 7). The decreasing trends 

for chloride, sulfate, tritium, and strontium-90 probably can 

be attributed to lack of recent wastewater disposal and to 

radioactive decay in the case of tritium and strontium-90.

USGS 42.—Chloride, sulfate, tritium, and strontium-90 

concentrations show decreasing trends, and nitrate and sodium 

show no trend (tables 5 and 7). The decreasing trends probably 

can be attributed to dilution and dispersion and the lack of 

recent wastewater disposal near this well and to radioactive 

decay for tritium and strontium-90.

USGS 43.—Chloride, tritium, and strontium-90 

concentrations show decreasing trends, and nitrate, sulfate, 

and sodium show no trend (tables 5 and 7). The decreasing 

trends probably can be attributed to dilution and dispersion 

and the lack of recent wastewater disposal near this well and 

to radioactive decay for tritium and strontium-90.

USGS 44.—Chloride, nitrate, sodium, tritium, and 

strontium-90 concentrations show decreasing trends and 

sulfate shows no trend (tables 5 and 7). The decreasing trends 

probably can be attributed to dilution and dispersion and 

the lack of recent wastewater disposal near this well and to 

radioactive decay for tritium and strontium-90.

USGS 45.—Chloride, sulfate, tritium, and strontium-90 

concentrations show decreasing trends, and nitrate and sodium 

show no trend (tables 5 and 7). The decreasing trends probably 

can be attributed to dilution and dispersion and the lack of 

recent wastewater disposal near this well and to radioactive 

decay for tritium and strontium-90.

USGS 46.—Chloride, nitrate, sodium, sulfate, tritium, 

and strontium-90 concentrations show decreasing trends 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay for 

tritium and strontium-90.

USGS 47.—Chloride, sodium, sulfate, tritium, and 

strontium-90 concentrations show decreasing trends, and 

nitrate shows no trend (tables 5 and 7). The decreasing trends 

probably can be attributed to dilution and dispersion and 

the lack of recent wastewater disposal near this well and to 

radioactive decay for tritium and strontium-90.

USGS 48.—Chloride, sulfate, tritium, and strontium-90 

concentrations show decreasing trends, and nitrate and sodium 

show no trend (tables 5 and 7). The decreasing trends probably 

can be attributed to dilution and dispersion and the lack of 

recent wastewater disposal near this well and to radioactive 

decay for tritium and strontium-90.
Factors Influencing Water-Quality Trends at Each Well 49

USGS 51.—Nitrate and tritium concentrations show 

decreasing trends, chloride, sodium, and sulfate show 

increasing trends, and strontium-90 shows no trend (tables 5

and 7). The decreasing trends probably can be attributed to 

dilution and dispersion and the lack of recent wastewater 

disposal near this well and to radioactive decay for tritium. 

The increasing trends for the other constituents may be due 

to remnant movement of these constituents from the old 

percolation ponds until 2002 when the new percolation ponds 

were put into service; as appendix D shows, concentrations do 

start to decrease slightly after 2002. 

USGS 52.—Chloride, tritium, and strontium-90 

concentrations show decreasing trends, and nitrate, sulfate, 

and sodium show no trend (tables 5 and 7). The decreasing 

trends probably can be attributed to dilution and dispersion 

and the lack of recent wastewater disposal near this well and 

to radioactive decay for tritium and strontium-90.

USGS 57.—Chloride, nitrate, sodium, sulfate, tritium, 

and strontium-90 concentrations show decreasing trends 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay for 

tritium and strontium-90.

USGS 59.—Chloride, nitrate, sodium, sulfate, tritium, 

and strontium-90 concentrations all show decreasing trends 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay for 

tritium and strontium-90.

USGS 67.—Chloride, sodium, sulfate, tritium, and 

strontium-90 concentrations show decreasing trends and 

nitrate shows an increasing trend (tables 5 and 7). The 

decreasing trends probably can be attributed to dilution and 

dispersion and the lack of recent wastewater disposal near this 

well and to radioactive decay for tritium and strontium-90. 

Nitrate concentrations have fluctuated through the period 

of record (appendix D) and the increase may indicate 

another possible source of contamination other than the 

infiltration ponds. 

USGS 77.—Chloride, chromium, sulfate, nitrate, and 

tritium concentrations show decreasing trends, fluoride shows 

an increasing trend, and sodium and strontium-90 show no 

trend (tables 5 and 7). The decreasing trends probably can 

be attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay 

for tritium.

USGS 82.—Chloride, nitrate, sodium, and tritium 

concentrations show decreasing trends, and sulfate and 

strontium-90 show no trend (tables 5 and 7). The decreasing 

trends probably can be attributed to dilution and dispersion 

and the lack of recent wastewater disposal near this well and 

to radioactive decay for tritium.

USGS 84.—Tritium concentrations show a decreasing 

trend, and chloride, nitrate, sodium, sulfate, and strontium-90 

show no trend. This well is near the Big Lost River, and 

concentrations of all the constituents seem to fluctuate 

opposite to increases and decreases of water levels in the 

aquifer (appendixes C and D). For example, all concentrations 

(except for the trace elements) were the lowest when the water 

level was at its highest about 1998–2000. The large decrease 

in zinc in the mid-2000s (appendix D) is probably due to the 

change of a galvanized sample pipe to stainless steel.

USGS 85.—Tritium, chloride, nitrate, and sodium 

concentrations show decreasing trends, and sulfate shows an 

increasing trend and strontium-90 shows no trend (tables 5

and 7). The decreasing trends are attributed to discontinued 

wastewater disposal at the INTEC and to radioactive decay for 

tritium. The increasing trend for sulfate could be due to water 

from the ATR Complex finally reaching this well. 

USGS 111.—Nitrate, sodium, sulfate, and tritium 

concentrations show decreasing trends, and chloride and 

strontium-90 show no trend (tables 5 and 7). The decreasing 

trends probably can be attributed to dilution and dispersion 

and the lack of recent wastewater disposal near this well and 

to radioactive decay for tritium.

USGS 112.—Chloride, nitrate, sodium, sulfate, tritium, 

and strontium-90 concentrations all show decreasing trends 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay for 

tritium and strontium-90.

USGS 113.—Chloride, sulfate, sodium, tritium, and 

strontium-90 concentrations show decreasing trends and 

nitrate shows no trend (tables 5 and 7). The decreasing trends 

probably can be attributed to dilution and dispersion and 

the lack of recent wastewater disposal near this well and to 

radioactive decay for tritium.

USGS 114.—Nitrate and tritium concentrations show 

decreasing trends, chloride shows an increasing trend, and 

sodium, sulfate, and strontium-90 show no trend (tables 5

and 7). The decreasing trends for nitrate and tritium probably 

can be attributed to lack of recent wastewater disposal near 

this well and to radioactive decay for tritium. The increase in 

chloride is probably due to the variable wastewater disposal in 

the past and slower groundwater movement to this well than to 

other wells in this area. 

USGS 115.—Tritium concentrations show a decreasing 

trend, chloride and sulfate show increasing trends, and nitrate, 

sodium, and strontium-90 show no trend (tables 5 and 7). 

The decreasing trends for tritium probably can be attributed 

to lack of recent wastewater disposal near this well and to 

radioactive decay. The increase in chloride and sulfate is 

probably due to variable wastewater disposal in the past and 

slower groundwater movement to this well than to other wells 

in this area. 
50 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

USGS 116.—Nitrate, sulfate, and tritium concentrations 

show decreasing trends, chloride shows an increasing trend, 

and sodium and strontium-90 show no trend (tables 5 and 7). 

The decreasing trends probably can be attributed to lack of 

recent wastewater disposal near this well and to radioactive 

decay for tritium. The increase in chloride is probably due 

to the more variable wastewater disposal of this constituent 

compared to the others in the past and slower groundwater 

movement to this well than to other wells in this area. 

USGS 123.—Chloride, nitrate, sulfate, sodium, tritium, 

and strontium-90 concentrations all show decreasing trends 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well, deepening of the well, and 

to radioactive decay for tritium and strontium-90. The large 

drop in concentrations in 2005 (appendix C and D) are due 

the deepening of this well in 2004 (Forbes and others, 2007), 

which resulted in sampling a larger zone of the upper part of 

the aquifer, thereby diluting future samples. 

USGS 128.—Chloride, nitrate, and tritium concentrations 

show decreasing trends, and strontium-90 shows no trend 

(tables 5 and 7). The decreasing trends probably can be 

attributed to dilution and dispersion and the lack of recent 

wastewater disposal near this well and to radioactive decay 

for tritium.

Aquifer Wells near Advanced Test 

Reactor Complex

MTR TEST.—Chloride, nitrate, sodium, sulfate, and 

tritium concentrations all show decreasing trends (tables 5

and 7). The decreasing trends are attributed to discontinued 

disposal of these constituents at the ATR Complex, along with 

clean-up of ponds the constituents were disposed of in the 

past. Although concentrations of tritium and sodium generally 

are decreasing, they show increases from 1990 to 1994 before 

decreasing (appendixes C and D); the increases were probably 

due to disposal in the radioactive-waste ponds reaching the 

aquifer before the ponds were taken out of service in the case 

of tritium and due to variable disposal in the chemical waste 

pond in the case of sodium. 

TRA Disposal.—Tritium, nitrate, sodium, and sulfate 

concentrations show decreasing trends and chloride and 

strontium-90 show no trend (tables 5 and 7). The decreasing 

trends are attributed to discontinued disposal of these 

constituents at the ATR Complex along with continued 

dilution and dispersion in the aquifer system, and because of 

radioactive decay for tritium. 

USGS 58.—Tritium concentrations show a decreasing 

trend, sodium and sulfate show increasing trends, and 

chloride, chromium, and strontium-90 show no trend (tables 5

and 7). The decreasing trends for tritium probably can be 

attributed to lack of recent wastewater disposal near this well 

and to radioactive decay. The increasing sodium and sulfate 

concentrations are probably due to wastewater disposal in the 

chemical and cold waste ponds at the ATR Complex.

USGS 65.—Chromium and tritium concentrations 

show decreasing trends, sodium and sulfate show increasing 

trends, and chloride, nitrate, and strontium-90 show no trend 

(tables 5 and 7). The decreasing trends for chromium and 

tritium probably can be attributed to lack of recent wastewater 

disposal and to radioactive decay in the case of tritium. The 

increasing sodium and sulfate concentrations are probably due 

to wastewater disposal in the chemical and cold waste ponds at 

the ATR Complex. The large decrease in zinc in the mid-2000s 

(table 7) is probably due to the change of a galvanized sample 

pipe to stainless steel.

USGS 76.—Tritium concentrations show a decreasing 

trend, sodium and sulfate show increasing trends, and 

chloride, chromium, nitrate, and strontium-90 show no trend 

(tables 5 and 7). The decreasing trend for tritium probably 

can be attributed to lack of recent wastewater disposal near 

this well and to radioactive decay. The increasing sodium and 

sulfate concentrations are probably due to wastewater disposal 

in the chemical and cold waste ponds at the ATR Complex.

USGS 79.—Chloride concentrations show a decreasing 

trend, and sodium, sulfate, and tritium show no trend (tables 5

and 7). The decreasing trend for chloride probably can be 

attributed to Big Lost River seepage in this part of the aquifer 

diluting the amount of chloride.

Aquifer Wells near Central Facilities Area

CFA-1.—Tritium, nitrate, and sulfate concentrations 

show decreasing trends and chloride, sodium, and 

strontium-90 show no trend (tables 5 and 7). The decreasing 

trends are attributed to discontinued disposal of these 

constituents at the INTEC along with continued dilution 

and dispersion in the aquifer system and also because of 

radioactive decay for tritium. 

CFA-2.—Chloride, sodium, sulfate, and nitrate 

concentrations all show increasing trends, tritium shows 

a decreasing trend, and strontium-90 shows no trend 

(tables 5 and 7). The decreasing trend for tritium probably 

can be attributed to lack of recent wastewater disposal and 

to radioactive decay. The increasing trends of the other 

constituents are probably due to a mass of water from periods 

of high wastewater disposal reaching this well and increasing 

the overall concentration in the aquifer over time. Busenberg 

and others (2001) indicated that this well contains about 

three-quarters young water , whereas CFA 1 consists of only 

about half young water, so this well may be more influenced 

by past wastewater disposal. This well is in the southern part 

of the CFA, and the increasing nitrate trend could be attributed 

to leakage from disposal at the former CFA mercury pond 

(U.S. Department Energy, 2011).
Factors Influencing Water-Quality Trends at Each Well 51

CFA LF 2-10.—Tritium, nitrate, and chromium 

concentrations show decreasing trends, sodium shows an 

increasing trend, and chloride and strontium-90 show no 

trend (tables 5 and 7). The decreasing trends are attributed to 

discontinued disposal of these constituents at the INTEC along 

with continued dilution and dispersion in the aquifer system 

and because of radioactive decay for tritium. The increasing 

sodium trend may be due to a mass of water from a previous 

higher disposal period reaching this well and increasing the 

overall concentration in the aquifer; this trend may be an 

indication that sodium is moving more slowly in the aquifer 

than some of the other constituents. 

CFA LF 3-9.—Nitrate concentrations show a decreasing 

trend, chloride shows an increasing trend, and tritium and 

strontium-90 show no trend (tables 5 and 7). The decreasing 

trend for nitrate is attributed to discontinued disposal at the 

INTEC along with continued dilution and dispersion in the 

aquifer system. The increasing trend for chloride is attributed 

to variable chloride disposal finally reaching this well and 

three of the four values collected since 2002 decreased from 

previous samples (appendix D).

USGS 127.—Sodium concentrations show an increasing 

trend, chromium shows a decreasing trend, and chloride, 

nitrate, tritium, and strontium-90 show no trend (tables 5 and 

7). The increasing trend of sodium probably is due to a mass 

of water from periods of higher wastewater disposal reaching 

this well and increasing the overall concentration in the 

aquifer over time. Although regional flow paths indicate that 

wastewater should move through this area, the water chemistry 

in this well is indicative of natural aquifer background, except 

for chromium.

Aquifer Wells near Radioactive Waste 

Management Complex

RWMC M3S.—Chloride concentrations show an 

increasing trend and nitrate, tritium, and strontium-90 show 

no trend (tables 5 and 7). The increasing chloride trend may 

be due to a mass of water from periods of higher wastewater 

disposal reaching this well and increasing the overall 

concentration in the aquifer over time, or may be due to slow 

seepage from buried waste at RWMC.

RWMC M7S.—Chloride and nitrate concentrations 

show an increasing trend and tritium and strontium-90 show 

no trend (tables 5 and 7). The increasing chloride and nitrate 

trends may be due to a mass of water from periods of higher 

wastewater disposal reaching this well and increasing the 

overall concentrations in the aquifer over time, or may be due 

to slow seepage from buried waste at RWMC. 

RWMC M11S.—Trend test results for constituents in 

water from this well indicate no trends for any of the major 

constituents for which trend analyses were completed (tables 5 

and 7). 

RWMC M12S.—Chloride and nitrate concentrations 

show increasing trends, chromium has a decreasing trend, 

and tritium and sodium show no trend (tables 5 and 7).The 

increasing chloride and nitrate trends may be due to a mass of 

water from periods of higher wastewater disposal reaching this 

well and increasing the overall concentrations in the aquifer 

over time. 

RWMC M13S.—Trend test results for constituents in 

water from this well indicate no trends for any of the major 

constituents for which trend analyses were completed (tables 5

and 7). Although regional flow paths indicate that wastewater 

from the INTEC/ATR Complex disposal should move 

through this area, the water chemistry in this well seems to be 

indicative of natural aquifer background concentrations except 

for chromium.

RWMC M14S.—Chromium and tritium concentrations 

show decreasing trends and no trend for chloride, nitrate, and 

sodium (tables 5 and 7). The decreasing concentrations are 

probably due to dilution and dispersion in the aquifer and also 

due to radioactive decay for tritium. 

RWMC Production.—Chloride and sodium 

concentrations along with the VOCs 1,1,1-trichloroethane, 

tetrachloroethene, carbon tetrachloride, trichloroethene, 

trichloromethane, and tribromomethane (tables 7 and 8, 

appendixes D and E) show increasing trends. Nitrate, sulfate, 

tritium, and strontium-90 show no trend. The increasing 

constituent trends are likely due to the movement of wastes 

buried at the RWMC moving to the aquifer.

USGS 87.—Chromium and nitrate concentrations show 

a decreasing trend; chloride, sodium, trichloromethane, 

trichloroethene, carbon tetrachloride, dichlorodifluoromethane, 

and tritium show increasing trends; and sulfate and 

strontium-90 show no trend (tables 5, 7, and 8). Both sodium 

and chloride show large increases in 2005 (appendix D). This 

well is along the flow path downgradient of the new INTEC 

percolation ponds installed in 2002, so the changes in these 

concentrations are attributed to disposal in the new ponds. The 

increases in the VOCs are attributed to continued leakage from 

buried waste at RWMC.

USGS 88.—Concentrations of 1,1,1-trichloroethane, 

carbon tetrachloride, nitrate, sodium, sulfate, and 

trichloroethene show decreasing trends, and chloride, 

tritium, and strontium-90 show no trend (tables 5, 7, and 8). 

The decreasing concentrations of the constituents may be 

an indication that clean-up at RWMC is having a positive 

influence on the aquifer where this well is located. 

USGS 89.—Nitrate concentrations show a decreasing 

trend, and chloride, sodium, sulfate, tritium, and strontium-90 

show no trend (tables 5 and 7). The decreasing concentrations 

of nitrate may be an indication that clean-up at RWMC is 

having a positive influence on the aquifer where this well 

is located. 
52 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

USGS 120.—Chloride, sodium, sulfate, and 

tetrachloroethene concentrations show decreasing trends, 

carbon tetrachloride and trichloromethane show an increasing 

trend, and nitrate, tritium, and strontium-90 show no trend 

(tables 5, 7, and 8). Sodium, sulfate, and several VOCs 

show large increases in the late 1990s and early 2000s and, 

conversely, nitrate shows a decrease in the same period 

(appendixes C and E). This well is near the INL spreading 

areas (fig. 1) and was influenced by spreading area water 

from 1996 to 1999 (Bartholomay and others, 2000; Nimmo 

and others, 2002). The nitrate decrease corresponds with 

an increase of dilution from spreading area water, but the 

other constituent increases do not. The increase of the VOCs 

may suggest a large movement of contaminants from the 

unsaturated zone below the RWMC during this period and 

spreading area recharge may have been a factor that influenced 

the increase in the movement of the buried waste. 

Aquifer Wells South of Facilities

USGS 104.—Chloride, sodium, and nitrate 

concentrations show increasing trends, and tritium shows no 

trend (tables 5 and 7). The increasing trends may represent 

the overall increase due to a mass of water from higher 

wastewater disposal periods reaching this well and increasing 

the overall concentration in the aquifer over time.

USGS 105.—Sodium and chloride concentrations show 

decreasing trends, nitrate shows an increasing trend, and 

tritium shows no trend (tables 5 and 7). The decreasing sodium 

and chloride may be an indicator that the sodium and chloride 

concentrations are originating from a different source than 

INTEC disposal and may have different travel times than other 

wells near the southern border. The presence of chromium 

concentrations above background concentrations may suggest 

some water originates from the ATR Complex area. 

USGS 106.—Tritium concentrations show a decreasing 

trend, sodium shows an increasing trend, and chloride shows 

no trend (tables 5 and 7). The increasing trend for sodium may 

be due to a mass of water from periods of higher wastewater 

disposal reaching this well and increasing the overall 

concentration in the aquifer over time. The decreasing tritium 

concentration is probably due to radioactive decay. 

USGS 108.—Chloride, nitrate, sodium, and tritium 

concentrations show no trend (tables 5 and 7). Concentrations 

of the inorganic constituents generally are at levels considered 

as background for the ESRP and water from this well probably 

represents well-mixed aquifer water with little influence from 

wastewater disposal.

USGS 124.—Chloride and nitrate concentrations show 

increasing trends, and sodium and tritium show no trend 

(tables 5 and 7). The increasing trends may be due to a mass of 

water from periods of higher wastewater disposal reaching this 

well and increasing the overall concentration in the aquifer 

over time. 

Perched Groundwater Wells near Idaho Nuclear 

Technology and Engineering Center

PW 1.—Chloride, tritium, and strontium-90 

concentrations show decreasing trends and sodium shows 

no trend (tables 5 and 7). This well gets all of its water from 

leakage from the old percolation ponds at the INTEC that were 

taken out of service in 2002 and the trends are attributed to 

variable wastewater disposal. 

PW 2.—Chloride, sodium, and tritium concentrations 

show decreasing trends, and sulfate and strontium-90 show 

no trend (tables 5 and 7). This well gets all of its water from 

leakage from the old percolation ponds at the INTEC that were 

taken out of service in 2002 and the trends are attributed to 

variable wastewater disposal. 

PW 3.—Chloride, tritium, and strontium-90 

concentrations show a decreasing trend and sodium shows 

no trend (tables 5 and 7). This well gets all of its water from 

leakage from the old percolation ponds at the INTEC that were 

taken out of service in 2002 and the trends are attributed to 

variable wastewater disposal. 

PW 4.—Chloride, sodium, strontium-90 and tritium 

concentrations show decreasing trends, and sulfate shows 

an increasing trend (tables 5 and 7). This well gets most of 

its water from leakage from the old percolation ponds at the 

INTEC that were taken out of service in 2002 and the trends 

are attributed to variable wastewater disposal. 

PW 5.—Tritium and strontium-90 concentrations show 

decreasing trends, and chloride and sodium show no trend 

(tables 5 and 7). This well gets all of its water from leakage 

from the old percolation ponds at the INTEC that were taken 

out of service in 2002 and the trends are attributed to variable 

wastewater disposal. 

PW 6.—Tritium concentrations show a decreasing 

trend and chloride and strontium-90 show no trend (tables 5

and 7). This well gets all of its water from leakage from 

the old percolation ponds at the INTEC that were taken out 

of service in 2002 and the trends are attributed to variable 

wastewater disposal.

USGS 50.—Chloride, nitrate, tritium, and strontium-90 

concentrations show decreasing trends, and sodium and sulfate 

show no trend (tables 5 and 7). This well gets most of its water 

from leakage from cracks in the old INTEC disposal well and 

leaky pipes around INTEC and the trends can be attributed to 

variable wastewater disposal and radioactive decay. The well 

was abandoned in 2009. 

Perched Groundwater Wells near Advanced 

Test Reactor Complex

CWP 1.—Sulfate concentrations show a decreasing trend 

and chloride, chromium, tritium, and strontium-90 show no 

trend (tables 5 and 7). This well gets most of its water from 
Factors Influencing Water-Quality Trends at Each Well 53

leakage from the cold waste ponds at the ATR Complex and 

the trend and lack of trends is due to variable discharge of the 

constituents in the wastewater. 

CWP 2.—Chloride concentrations show no trend 

(table 7). This well gets most of its water from leakage from 

the cold waste ponds at the ATR Complex and the lack of 

trend is due to variable discharge in the wastewater. 

CWP 3.—Chromium concentrations show a decreasing 

trend and chloride, sulfate, tritium, and strontium-90 show no 

trend (tables 5 and 7). This well gets most of its water from 

leakage from the cold waste ponds at the ATR Complex and 

the trends are due to variable discharge of the constituents in 

the wastewater. 

CWP 4.—Chloride concentrations show a decreasing 

trend and tritium and strontium-90 show no trend (tables 5 and 

7). This well gets most of its water from leakage from the cold 

waste ponds at the ATR Complex and the decreasing trend is 

attributed to variable wastewater disposal. 

CWP 5.—Tritium concentrations show no trend (table 5). 

CWP 8.—Chloride and sulfate concentrations show 

decreasing trends and chromium, tritium, and strontium-90 

show no trend (tables 5 and 7). This well gets most of its water 

from leakage from the cold waste ponds at the ATR Complex 

and the trends are attributed to variable wastewater disposal. 

 PW 8.—Chromium, sulfate, tritium, and strontium-90 

concentrations show decreasing trends, and chloride and 

sodium show no trend (tables 5 and 7). This well gets most 

of its water from leakage from the old radioactive-waste 

infiltration ponds that were discontinued in 1993 and from 

leakage from the cold waste ponds near the ATR Complex. 

The trends are attributed to variable wastewater disposal and 

to radioactive decay for tritium and strontium-90. 

PW 9.—Chromium, sodium, sulfate, and tritium 

concentrations show decreasing trends, chloride shows an 

increasing trend, and strontium-90 shows no trend (tables 5

and 7). This well gets most of its water from leakage from the 

old radioactive-waste infiltration ponds that were discontinued 

in 1993 and from leakage from the cold waste ponds near 

the ATR Complex. The trends are attributed to variable 

wastewater disposal and to radioactive decay for tritium.

TRA A 13.—Tritium and strontium-90 concentrations 

show decreasing trends, and chloride shows an increasing 

trend (tables 5 and 7). This well gets most of its water from 

leakage from the old radioactive-waste infiltration ponds 

that were discontinued in 1993. The trends can be attributed 

to variable discharge and radioactive decay. Sampling was 

discontinued in 2008 and the well was later abandoned. 

TRA A 77.—Tritium concentrations show a decreasing 

trend, chloride and strontium-90 show increasing trends 

(table 5 and 7). This well gets most of its water from 

leakage from a retention basin prior to flow to the old 

radioactive‐waste infiltration ponds that were discontinued 

in 1993. The trends can be attributed to variable wastewater 

disposal and radioactive decay and a different affinity for 

strontium-90 to absorb to sediments and then possibly 

get reintroduced later to the water column through cation 

exchange. Sampling was discontinued in 2008 and the well 

was later abandoned. 

USGS 53.—Tritium and strontium-90 concentrations 

show decreasing trends, and chloride, chromium, and sodium 

show no trend (tables 5 and 7). This well previously was used 

as a disposal well and gets most of its water from leakage 

from the old radioactive-waste infiltration ponds that were 

discontinued in 1993 and from leakage from the cold waste 

ponds near the ATR Complex. The trends (or lack of trends) 

are attributed to variable wastewater disposal, discontinuation 

of disposal to the radioactive waste ponds, and radioactive 

decay for tritium and strontium-90.

USGS 54.—Chromium, sulfate, tritium, and strontium-90 

concentrations show decreasing trends, and chloride and 

sodium show no trend (tables 5 and 7). This well historically 

got most of its water from leakage from the old radioactivewaste infiltration ponds that were discontinued in 1993 

and from leakage from the cold waste ponds near the ATR 

Complex. The trends (or lack of trends) are attributed to 

variable wastewater disposal, discontinuation of disposal to 

the radioactive waste ponds, and radioactive decay for tritium 

and strontium-90.

USGS 55.—Chloride and chromium concentrations 

show decreasing trends, strontium-90 shows an increasing 

trend, and sodium, sulfate, and tritium show no trend (tables 5

and 7). This well historically got most of its water from 

leakage from the old radioactive-waste infiltration ponds 

that were discontinued in 1993 and from leakage from the 

cold waste ponds near the ATR Complex. The trends (or 

lack of trends) are attributed to variable wastewater disposal. 

Strontium-90 shows an increasing trend through 2006 and 

then concentrations decrease (appendix C). The increase 

could be due to sodium discharge into the chemical waste 

pond exchanging with strontium-90 making it mobile; the 

subsequent decrease after 2006 could be due to the closing of 

the chemical waste ponds in 1999. Although sodium does not 

show a statistically significant trend, sodium concentrations 

in this well do somewhat show an inverse relationship with 

strontium-90 concentrations (appendixes C and D).

USGS 56.—Tritium concentrations show a decreasing 

trend, and chloride, chromium, sodium, and strontium-90 

show no trend (tables 5 and 7). This well gets most of its 

water from leakage from the old radioactive-waste infiltration 

ponds that were discontinued in 1993 and from leakage from 

the cold waste ponds near the ATR Complex. The trends (or 

lack of trends) are attributed to variable wastewater disposal, 

discontinuation of disposal to the radioactive waste ponds, and 

radioactive decay for tritium.

USGS 60.—Chromium, sulfate, and tritium 

concentrations show decreasing trends, and chloride, 

sodium, and strontium-90 show no trend (tables 5 and 7). 

This well gets most of its water from leakage from the old 
54 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

radioactive‐waste infiltration ponds that were discontinued 

in 1993 and from leakage from the cold waste ponds near the 

ATR Complex. The trends (or lack of trends) are attributed to 

variable wastewater disposal.

USGS 61.—Chromium, sodium, and tritium 

concentrations show decreasing trends, and chloride, sulfate, 

and strontium-90 show no trend (tables 5 and 7). This well 

gets most of its water from leakage from the old radioactivewaste infiltration ponds that were discontinued in 1993 

and from leakage from the cold waste ponds near the ATR 

Complex and the trends (or lack of trends) are attributed 

to variable wastewater disposal and to radioactive decay 

for tritium. 

USGS 62.—Chromium and tritium concentrations 

show decreasing trends, and chloride, chromium, sulfate, and 

strontium-90 show no trend (tables 5 and 7). This well gets 

most of its water from leakage from the old radioactive-waste 

infiltration ponds that were discontinued in 1993 and from 

leakage from the cold waste ponds near the ATR Complex. 

The trends (or lack of trends) are attributed to variable 

wastewater disposal and to radioactive decay for tritium. 

USGS 63.—Chromium, sulfate, tritium, and strontium-90 

concentrations show a decreasing trend, and chloride and 

sodium show no trend (tables 5 and 7). This well gets most 

of its water from leakage from the old radioactive-waste 

infiltration ponds that were discontinued in 1993 and from 

leakage from the cold waste ponds near the ATR Complex. 

The trends (or lack of trends) are attributed to variable 

wastewater disposal and to radioactive decay for tritium and 

strontium-90. 

USGS 66.—Tritium concentrations show a decreasing 

trend, and chromium, sodium, sulfate, and strontium-90 show 

no trend (tables 5 and 7). This well gets most of its water from 

leakage from the old radioactive-waste infiltration ponds that 

were discontinued in 1993 and from leakage from the cold 

waste ponds near the ATR Complex. The trends (or lack of 

trends) are attributed to variable wastewater disposal and to 

radioactive decay for tritium. 

USGS 68.—Chloride, sodium, and sulfate concentrations 

show decreasing trends, chromium shows an increasing 

trend, and tritium and strontium-90 show no trend (tables 5

and 7). This well gets most of its water from leakage from 

the chemical waste infiltration ponds that were discontinued 

in 1999 and the cold waste-ponds at the ATR Complex. The 

trends are attributed to variable wastewater disposal. 

USGS 69.—Chloride and sulfate concentrations show 

decreasing trends, and chromium, sodium, tritium, and 

strontium-90 show no trend (tables 5 and 7). This well gets 

most of its water from leakage from the old radioactive-waste 

infiltration ponds that were discontinued in 1993 and from 

leakage from the cold waste ponds near the ATR Complex. 

The trends (or lack of trends) are attributed to variable 

wastewater disposal. 

USGS 70.—Chloride, chromium, tritium, and 

strontium-90 concentrations show decreasing trends, and 

sulfate and sodium show no trend (tables 5 and 7). This well 

historically got most of its water from leakage from the old 

radioactive waste infiltration ponds that were discontinued in 

1993 and from leakage from the cold waste ponds near the 

ATR Complex. The trends (or lack of trends) are attributed 

to variable wastewater disposal, discontinuation of disposal 

to the radioactive waste infiltration ponds, and to radioactive 

decay for tritium and strontium-90.

USGS 71.—Chromium and tritium concentrations show 

decreasing trends; sodium shows an increasing trend; and 

chloride, sulfate, and strontium-90 show no trend (tables 5 and 

7). This well gets most of its water from leakage from the old 

radioactive-waste infiltration ponds that were discontinued 

in 1993 and from leakage from the cold waste ponds near the 

ATR Complex and the trends (or lack of trends) are attributed 

to variable wastewater disposal and to radioactive decay 

for tritium. 

USGS 72.—Sulfate concentrations show a decreasing 

trend, and chloride, chromium, sodium, tritium, and 

strontium-90 show no trend (tables 5 and 7). This well 

probably gets most of its water from leakage from landscape 

irrigation water and from other unknown sources around 

the ATR Complex and possibly some minimal influence by 

wastewater ponds around the ATR Complex. The decreasing 

sulfate may be an indication that the water was influenced by 

the chemical waste pond and the decreases are probably due to 

the discontinued use of the pond in 1999. 

USGS 73.—Chromium and tritium concentrations show 

decreasing trends, chloride shows an increasing trend, and 

sodium, sulfate, and strontium-90 show no trend (tables 5 and 

7). This well gets most of its water from leakage from the old 

radioactive-waste infiltration ponds that were discontinued 

in 1993 and from leakage from the cold waste ponds near 

the ATR Complex. The trends are attributed to variable 

wastewater disposal and to radioactive decay for tritium.

USGS 78.—Chromium concentrations show a decreasing 

trend, and chloride, sulfate, sodium, tritium and strontium-90 

show no trend (tables 5 and 7). This well probably gets all of 

its water from recharge from the Big Lost River (Orr, 1999), 

and the increasing chromium may be due to variable reporting 

levels as only four concentrations exceeded the reporting 

level (appendix D). 

Perched Groundwater Well at Radioactive 

Waste Management Complex

USGS 92.—Chloride, tritium, and strontium-90 

concentrations show no trend (tables 5 and 7). 
Summary and Conclusions 55

Summary and Conclusions

The U.S. Geological Survey (USGS), in cooperation 

with the U.S. Department of Energy, has maintained a 

water-quality monitoring network at the Idaho National 

Laboratory (INL) since 1949 to define the quality of water 

for human and industrial use and to better understand the 

location and movement of contaminants in the eastern Snake 

River Plain aquifer underlying the INL. Trends in constituent 

concentrations for 64 regional aquifer wells and 35 perched 

groundwater wells were analyzed from 1981 through 2012. 

Constituents analyzed included some combination of tritium, 

strontium-90, cesium-137, plutonium-238, plutonium-239, 

-240 (undivided), americium-241, gross alpha- and betaparticle radioactivity, calcium, magnesium, potassium, silica, 

sodium, bromide, chloride, fluoride, sulfate, nitrate (as N), 

orthophosphate (as P), chromium and other trace elements, 

and total organic carbon. The wells selected for analysis in this 

report likely were affected by wastewater disposal practices 

at the INL. Concentration trends were determined to assist 

with future management decisions concerning which wells to 

sample and which constituent types to monitor.

Water-quality trends were determined from groundwater 

data collected after the date of pump installations to eliminate 

variability associated with sample-collection methods. 

Concentration trends also were from data sets from the 

same laboratory, either the USGS National Water Quality 

Laboratory or the Department of Energy Radiological and 

Environmental Sciences Laboratory. Data not used for 

the trend analyses included data from special INL studies, 

data collected prior to 1981 when laboratory methods were 

unknown and quality assurance data were not routinely 

collected, and data collected from different depths in the 

aquifer using a thief sampler. Outlier data that did not correlate 

with field-specific conductance measurements and replicate 

values were not used.

The data were processed using custom computer scripts 

developed in the R programming language. All R functions 

written for this report are stored in an R-package called 

“Trends.” In addition to the base packages included with 

R, Trends depends on the “Survival” package. The Trends 

package identifies statistical trends in water-quality data for 

multiple constituents and sample sites using a parametric 

survival regression model for left-censored data (values 

reported as less than a laboratory reporting level [LRL]), 

interval-censored data (data with an associated uncertainty), 

and uncensored data. This “Trends” package also calculates 

summary statistics of mean, median, minimum, maximum, 

and standard deviation for multiple constituents, and 

automates plotting the data and regression lines.

 A significance level of 0.05 was selected to determine if 

the result of the test was statistically significant. A two-sided 

p-value that was less than or equal to 0.05 indicated that there 

was a statistically significant correlation, or trend, in the data. 

The sign of the percent change per year indicated whether 

there was an increasing or decreasing trend if a significant 

correlation existed. If p-values were greater than 0.05, there 

was no statistically significant correlation, or trend, between 

time and concentration.

Data for field measurements of pH, specific conductance, 

and water temperature were analyzed for trends. Of the 

64 aquifer wells measured for pH, 43 of the wells had a 

decreasing pH trend, and 20 wells had no trend. Only one 

well showed an increasing trend in pH. Of the 35 perched 

groundwater wells measured, 12 had a decreasing pH trend, 

3 had an increasing pH trend, and 20 had no trend. It was 

difficult to assess whether or not the trends for pH were due 

to actual changes in the aquifer or perched groundwater, or 

because of variability in the sample collection methods or 

meter types. 

Sixty-four aquifer wells were analyzed for a trend in 

specific conductance; 34 had a decreasing trend, 16 had no 

trend, and 14 had an increasing trend. Most of the wells that 

showed decreasing or no trend are located near the Idaho 

Nuclear Technology and Engineering Center (INTEC), 

and the decreasing trends may be a response to decreased 

wastewater disposal since 1989 or discontinued use of the old 

percolation ponds south of the INTEC in 2002. Most aquifer 

wells that showed an increasing trend are located south and 

southeast of the INTEC, or north of the RWMC. Most of the 

specific conductance data in perched groundwater wells near 

the INTEC and the Advanced Test Reactor Complex (ATR 

Complex) showed either a decreasing trend or no trend. 

Sixty-four aquifer wells were evaluated for temperature 

trends; 32 showed a decreasing trend, 29 showed no trend, and 

3 showed an increasing trend. Of the 35 perched groundwater 

wells analyzed for temperature trends, 13 showed a decreasing 

trend, 17 showed no trend, and 5 showed an increasing trend. 

All the perched groundwater wells with an increasing trend in 

temperature are near the ATR Complex.

Of the 63 aquifer wells that were analyzed for tritium 

concentration trends, 45 showed decreasing trends, 1 

showed an increasing trend, and 18 showed no trends. Of the 

33 perched groundwater wells that were analyzed for tritium 

trends, 22 showed a decreasing trend and 11 showed no trend. 

The decreasing trends can be attributed to decreased disposal 

at facilities and to the radioactive decay of tritium.

Fifty-two aquifer wells were analyzed for strontium-90 

concentration trends; 20 showed a decreasing strontium-90 

trend and 32 showed no trend. Of the 32 perched groundwater 

wells that were analyzed for strontium-90 trends, 11 showed 

a decreasing trend, 19 showed no trend, and 2 showed an 

increasing trend. The two wells that showed an increasing 

trend (TRA A 77 and USGS 55) are near the radioactivewaste infiltration ponds at the ATR Complex, and could 

be influenced by strontium-90 that was discharged to the 

radioactive-waste infiltration ponds before they were replaced 

by lined evaporation ponds in 1993.
56 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Water from 63 wells was analyzed for chloride 

concentration trends. Thirty-one of these wells had decreasing 

trends, 17 had no trend, and 15 had an increasing trend. Most 

wells near the INTEC and ATR Complex showed decreasing 

or no trends for chloride, probably the result of decreased 

disposal of wastewater and (or) discontinued use of the old 

percolation ponds south of the INTEC and redirection of 

discharge to the new percolation ponds 2 miles southwest of 

the INTEC in 2002. Chloride concentrations in some wells 

south of the INTEC were influenced by episodic recharge from 

the Big Lost River; chloride concentrations decreased during 

wetter periods when there is probably more recharge from the 

Big Lost River, and increased during dry periods, when there 

is less recharge.

 Perched groundwater analyzed for chloride concentration 

trends showed that 10 perched groundwater wells had 

decreasing trends, 18 had no trend, and 4 had increasing 

chloride concentration trends.

Sodium hydrate was a predominant constituent in 

wastewater discharged to the chemical-waste infiltration 

pond at the ATR Complex, and sodium and chloride were 

predominant chemical constituents in wastewater discharged 

at the INTEC and the Central Facilities Area (CFA). Of the 

59 aquifer wells analyzed for sodium concentration trends, 

22 wells showed a decreasing trend, 23 showed no trend, 

and 14 showed an increasing trend. The increasing trend for 

sodium in some wells could be due to the long term influence 

of wastewater disposal from upgradient facilities and the 

lack of trend for chloride could be because it is more mobile 

than sodium and more dispersed in the aquifer system. Five 

perched groundwater wells analyzed for sodium trends 

had decreasing trends, 18 had no trend, and 1 well had an 

increasing trend. 

Forty-eight aquifer wells were analyzed for sulfate 

concentration trends; 24 had decreasing trends, 11 had no 

trend, and 13 had increasing trends. Most aquifer wells that 

had increasing trends were located downgradient of the 

INTEC or ATR Complex, in the general direction of regional 

groundwater flow to the southwest. Closer to the facilities, 

sulfate trends either decreased or there was no trend. Most 

perched groundwater wells near the INTEC and ATR Complex 

showed decreasing or no trends. 

Fifty-nine aquifer wells were analyzed for trends in 

nitrate concentrations; 28 showed a decreasing trend, 23 

showed no trend, and 8 showed an increasing trend. As was 

shown for chloride, sodium, and sulfate for wells near the Big 

Lost River, the nitrate concentrations fluctuated in response to 

recharge from the Big Lost River. Only one well completed in 

perched groundwater at the INTEC was analyzed for a nitrate 

trend; it had a decreasing trend. 

Trace element concentrations from two wells were 

analyzed for trends. Well USGS 65 showed no trend for 

aluminum, antimony, copper, manganese, nickel, and 

selenium. Barium, cadmium, cobalt, lead, and zinc had 

decreasing trends, and arsenic, molybdenum, and uranium 

had increasing trends. Well USGS 84 showed no trend for 

aluminum, antimony, barium, manganese, molybdenum, 

selenium and uranium. Cadmium, cobalt, copper, lead, nickel, 

and zinc showed decreasing trends, and arsenic showed an 

increasing trend.

Twenty-five aquifer wells were analyzed for chromium 

concentration trends; 14 showed no trend, 8 showed 

decreasing trends, and 3 showed increasing trends. The three 

wells that showed increasing trends are located at or just 

downgradient of the INTEC. One well downgradient of the 

ATR Complex showed a decreasing trend. Most of the other 

wells showing decreasing trends are located near the CFA 

and the Radioactive Waste Management Complex (RWMC). 

Of the 21 perched groundwater wells analyzed for chromium 

trends, 7 showed no trend, 13 showed a decreasing trend, and 

1 showed an increasing trend. All the perched groundwater 

wells that had decreasing trends are south or southeast of the 

ATR Complex and the decreasing trends are probably due to 

discontinued disposal. 

Volatile organic compound (VOC) concentration 

trends were analyzed for nine aquifer wells for this study. 

Historically, concentrations of VOCs in water samples 

from several wells at and near the RWMC exceeded the 

reporting levels. Concentrations for all VOCs except carbon 

tetrachloride were less than the maximum contaminant level 

(MCL) for drinking water. A plot of carbon tetrachloride 

concentrations in water from the RWMC Production Well 

indicates that concentration trends in this well have increased 

since 1987; however, trend analyses of data collected since 

2005 show no statistically significant trend indicating that 

engineering practices designed to reduce movement of volatile 

organic compounds to the aquifer may be having a positive 

effect on the aquifer. The RWMC Production well also had 

increasing trends for trichloroethene, trichloromethane, 

tetrachloroethene, 1,1,1-trichloroethane, and tribromomethane.

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Table 4 63

Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells

Idaho Nuclear Technology and Engineering Center

CPP 1 433433112560201 pH 46 7.44 8.08 7.96 7.92 0.125 -0.151 0.000 –

Specific conductance 46 350 465 405 405 18.2 -0.387 0.000 –

Temperature 46 11.6 13.0 12.0 12.1 0.333 -0.158 0.010 –

CPP 2 433432112560801 pH 39 7.42 8.14 7.95 7.89 0.168 -0.192 0.000 –

Specific conductance 39 365 426 405 400 18.0 -0.449 0.000 –

Temperature 39 11.5 13.7 12.0 12.2 0.501 0.101 0.279 none

RIFLE RANGE 433243112591101 pH 13 7.31 7.99 7.85 7.77 0.194 0.091 0.643 none

Specific conductance 13 418 488 450 451 26.0 1.20 0.007 +

Temperature 13 12.1 13.6 12.4 12.5 0.395 0.065 0.787 none

USGS 20 433253112545901 pH 40 7.48 8.06 7.95 7.92 0.127 -0.059 0.143 none

Specific conductance 40 280 394 362 360 21.3 0.617 0.000 +

Temperature 40 11.1 14.0 12.6 12.6 0.603 -0.059 0.614 none

USGS 34 433334112565501 pH 38 7.69 8.12 7.98 7.93 0.110 -0.074 0.034 –

Specific conductance 38 380 455 424 424 20.4 0.035 0.773 none

Temperature 38 11.0 13.0 12.0 12.0 0.466 -0.273 0.005 –

USGS 35 433339112565801 pH 38 7.59 8.10 7.98 7.94 0.119 -0.167 0.000 –

Specific conductance 38 372 490 440 430 23.7 -0.109 0.427 none

Temperature 38 11.0 13.5 11.6 11.8 0.523 -0.242 0.022 –

USGS 36 433330112565201 pH 56 7.64 8.09 7.91 7.89 0.100 -0.097 0.001 –

Specific conductance 56 418 601 491 503 61.0 -1.31 0.000 –

Temperature 56 11.5 14.0 12.5 12.6 0.531 -0.541 0.000 –

USGS 37 433326112564801 pH 40 7.46 8.05 7.90 7.88 0.111 -0.088 0.009 –

Specific conductance 40 345 828 618 622 142 -1.82 0.000 –

Temperature 40 11.0 14.0 13.0 13.1 0.681 -0.609 0.000 –

USGS 38 433322112564301 pH 37 7.64 8.78 7.84 7.90 0.239 -0.181 0.016 –

Specific conductance 37 417 979 732 698 200 -3.21 0.000 –

Temperature 37 10.3 15.0 13.5 13.4 0.958 -0.730 0.000 –

USGS 39 433343112570001 pH 57 7.38 8.13 7.98 7.93 0.158 -0.174 0.000 –

Specific conductance 57 361 453 420 416 23.4 0.066 0.626 none

Temperature 57 10.6 13.8 11.6 11.7 0.616 0.311 0.009 +
64 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. 

p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 40 433411112561101 pH 56 7.46 8.06 7.94 7.92 0.119 -0.043 0.265 none

Specific conductance 56 418 593 471 476 38.2 -0.603 0.002

–

Temperature 56 11.8 14.5 13.1 13.2 0.552 -0.512 0.000

–

USGS 41 433409112561301 pH 38 7.57 8.07 7.95 7.91 0.116 -0.114 0.002

–

Specific conductance 38 409 521 446 451 26.6 -0.594 0.000

–

Temperature 38 11.3 13.5 12.3 12.2 0.378 -0.222 0.003

–

USGS 42 433404112561301 pH 38 7.30 8.08 7.95 7.91 0.148 -0.109 0.023

–

Specific conductance 38 384 498 443 445 27.4 -0.600 0.000

–

Temperature 38 11.6 13.5 12.2 12.3 0.355 -0.237 0.001

–

USGS 43 433415112561501 pH 37 7.60 8.30 8.05 8.02 0.170 -0.191 0.000

–

Specific conductance 37 445 590 483 483 28.2 -0.698 0.000

–

Temperature 37 11.8 15.0 12.9 13.0 0.597 -0.418 0.000

–

USGS 44 433409112562101 pH 46 7.44 8.10 7.94 7.89 0.147 -0.115 0.008

–

Specific conductance 46 369 446 420 413 22.1 -0.743 0.000

–

Temperature 46 11.0 14.5 11.7 11.9 0.691 -0.356 0.006

–

USGS 45 433402112561801 pH 39 7.51 8.12 7.96 7.89 0.154 -0.182 0.000

–

Specific conductance 39 384 455 427 422 18.5 -0.549 0.000

–

Temperature 39 11.0 13.1 12.0 12.2 0.458 -0.039 0.664 none

USGS 46 433407112561501 pH 38 7.36 8.03 7.97 7.89 0.157 -0.133 0.008

–

Specific conductance 38 381 515 437 437 27.9 -0.774 0.000

–

Temperature 38 11.7 13.5 12.1 12.3 0.450 -0.260 0.004

–

USGS 47 433407112560301 pH 44 7.33 8.01 7.91 7.85 0.143 -0.180 0.000

–

Specific conductance 44 410 572 478 481 37.1 -0.446 0.010

–

Temperature 44 11.2 15.0 13.8 13.7 0.767 -0.613 0.000

–

USGS 48 433401112560301 pH 39 7.42 8.66 7.88 7.88 0.191 -0.129 0.031

–

Specific conductance 39 395 525 460 461 25.6 -0.437 0.002

–

Temperature 39 11.8 14.2 13.1 13.1 0.457 -0.262 0.003

–

USGS 51 433350112560601 pH 38 7.57 8.83 8.15 8.06 0.308 -0.472 0.000

–

Specific conductance 38 460 960 725 687 137 2.60 0.000

+

Temperature 38 12.5 14.1 13.3 13.3 0.398 -0.120 0.103 none
Table 4 65

Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater 

wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 52 433414112554201 pH 39 7.46 8.66 7.91 7.90 0.185 -0.207 0.000 –

Specific conductance 39 416 489 455 452 18.8 -0.320 0.002 –

Temperature 39 12.3 14.0 13.0 13.0 0.359 -0.217 0.001 –

USGS 57 433344112562601 pH 57 7.44 8.80 7.89 7.85 0.177 0.024 0.632 none

Specific conductance 57 407 1,020 805 769 178 -2.46 0.000 –

Temperature 57 10.8 15.5 13.3 13.4 0.749 -0.702 0.000 –

USGS 59 433354112554701 pH 37 7.68 8.43 7.99 8.03 0.181 -0.236 0.000 –

Specific conductance 37 389 1,040 519 567 172 -1.73 0.005 –

Temperature 37 12.9 15.4 14.1 14.2 0.616 -0.243 0.027 –

USGS 67 433344112554101 pH 32 7.44 8.47 7.87 7.86 0.170 -0.199 0.000 –

Specific conductance 32 519 909 704 717 135 -1.09 0.018 –

Temperature 32 11.5 14.5 13.3 13.4 0.630 -0.476 0.000 –

USGS 77 433315112560301 pH 38 7.34 8.07 7.88 7.82 0.159 -0.146 0.004 –

Specific conductance 38 550 847 730 721 78.4 -0.431 0.111 none

Temperature 38 11.0 15.5 12.1 12.2 0.690 -0.204 0.112 none

USGS 82 433401112551001 pH 55 7.09 8.16 8.04 7.99 0.177 -0.176 0.001 –

Specific conductance 55 321 406 343 342 12.0 -0.190 0.018 –

Temperature 55 11.2 15.0 12.1 12.2 0.553 -0.173 0.090 none

USGS 84 433356112574201 pH 36 7.61 8.41 8.00 7.97 0.173 -0.231 0.000 –

Specific conductance 36 376 460 429 420 25.3 -0.164 0.295 none

Temperature 36 10.0 13.1 12.4 12.3 0.608 0.253 0.060 none

USGS 85 433246112571201 pH 40 7.33 8.06 7.95 7.91 0.142 -0.141 0.002 –

Specific conductance 40 422 605 497 496 49.9 -1.23 0.000 –

Temperature 40 10.5 13.5 12.4 12.4 0.485 -0.245 0.012 –

USGS 111 433331112560501 pH 40 7.78 8.64 8.04 8.05 0.153 0.031 0.492 none

Specific conductance 40 553 817 615 645 78.5 -0.864 0.000 –

Temperature 40 11.0 15.0 13.1 13.2 0.714 -0.124 0.336 none

USGS 112 433314112563001 pH 61 7.39 8.17 7.88 7.85 0.137 -0.092 0.016 –

Specific conductance 61 435 1,015 783 778 172 -2.98 0.000 –

Temperature 61 11.8 15.5 13.3 13.4 0.599 -0.522 0.000 –
66 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. 

p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 113 433314112561801 pH 59 7.55 8.08 7.90 7.87 0.110 -0.045 0.156 none

Specific conductance 59 480 1,129 978 931 176 -2.76 0.000

–

Temperature 59 12.1 14.6 13.0 13.0 0.385 -0.091 0.169 none

USGS 114 433318112555001 pH 59 7.40 8.04 7.88 7.83 0.140 -0.178 0.000

–

Specific conductance 59 545 638 570 578 21.4 0.225 0.005

+

Temperature 59 12.2 14.8 13.2 13.3 0.606 -0.244 0.014

–

USGS 115 433320112554101 pH 59 7.34 8.21 7.94 7.89 0.158 -0.165 0.000

–

Specific conductance 59 369 494 403 408 23.6 0.265 0.032

+

Temperature 59 12.3 14.0 13.0 13.0 0.325 0.030 0.584 none

USGS 116 433331112553201 pH 58 7.32 8.22 8.02 7.98 0.151 0.008 0.851 none

Specific conductance 58 515 725 608 607 52.9 0.591 0.002

+

Temperature 58 11.3 14.0 12.5 12.5 0.461 -0.246 0.004

–

USGS 123 433352112561401 pH 33 7.61 9.14 7.89 7.92 0.255 0.197 0.020

+

Specific conductance 33 351 832 699 629 172 -4.01 0.000

–

Temperature 33 10.8 15.0 14.0 13.9 0.734 -0.137 0.382 none

USGS 128 433250112565601 pH 11 7.55 8.02 7.74 7.77 0.165 -0.315 0.089 none

Specific conductance 11 436 531 440 450 27.6 -1.16 0.020

–

Temperature 11 10.9 12.7 12.1 12.0 0.571 0.158 0.712 none

Advanced Test Reactor Complex

MTR TEST 433520112572601 pH 38 7.57 8.10 7.93 7.91 0.123 -0.114 0.005

–

Specific conductance 38 395 711 525 521 98.8 -2.36 0.000

–

Temperature 38 12.2 14.0 13.0 13.1 0.387 -0.237 0.002

–

TRA Disposal 433506112572301 pH 41 7.47 8.11 7.90 7.86 0.148 -0.111 0.009

–

Specific conductance 41 418 495 460 456 21.0 -0.582 0.000

–

Temperature 41 12.7 17.0 13.4 13.6 0.949 -0.243 0.093 none

USGS 58 433500112572502 pH 35 7.42 8.23 7.95 7.91 0.173 -0.185 0.002

–

Specific conductance 35 416 460 443 442 9.29 -0.118 0.038

–

Temperature 35 12.3 13.5 12.7 12.8 0.282 -0.032 0.582 none

USGS 65 433447112574501 pH 61 7.52 8.27 7.98 7.94 0.134 -0.123 0.001

–

Specific conductance 61 572 643 609 612 14.5 0.118 0.025

+

Temperature 61 11.2 14.0 13.2 13.3 0.479 -0.340 0.000

–
Table 4 67

Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater 

wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Advanced Test Reactor Complex—Continued

USGS 76 433425112573201 pH 42 7.62 8.21 8.00 7.97 0.117 -0.121 0.000 –

Specific conductance 42 422 470 445 444 9.26 -0.082 0.096 none

Temperature 42 12.1 13.6 12.5 12.6 0.348 -0.222 0.001 –

USGS 79 433505112581901 pH 38 7.59 8.14 7.94 7.91 0.135 -0.095 0.030 –

Specific conductance 38 350 422 393 391 15.0 -0.122 0.219 none

Temperature 38 12.0 13.0 12.5 12.4 0.256 -0.015 0.781 none

Central Facilities Area

CFA 1 433204112562001 pH 60 7.55 7.98 7.81 7.79 0.103 -0.120 0.000 –

Specific conductance 60 560 733 662 651 46.5 0.076 0.635 none

Temperature 60 9.50 13.0 12.0 12.0 0.437 0.054 0.527 none

CFA 2 433144112563501 pH 55 7.35 8.07 7.82 7.76 0.150 -0.222 0.000 –

Specific conductance 55 580 864 701 699 86.3 1.81 0.000 +

Temperature 55 10.5 12.5 12.0 12.0 0.364 0.060 0.383 none

CFA LF 3-9 433216112571001 pH 12 7.50 7.89 7.73 7.73 0.123 -0.055 0.585 none

Specific conductance 12 657 819 723 724 46.2 0.351 0.374 none

Temperature 12 11.2 13.4 12.5 12.4 0.655 -0.754 0.025 –

CFA LF 2-10 433216112563301 pH 31 7.50 8.10 7.97 7.92 0.156 -0.139 0.035 –

Specific conductance 31 452 504 488 483 17.1 -0.433 0.000 –

Temperature 31 12.3 13.5 12.6 12.6 0.231 0.085 0.155 none

USGS 127 433058112572201 pH 18 7.49 8.23 8.08 7.99 0.220 -0.099 0.571 none

Specific conductance 18 287 307 303 301 5.70 -0.296 0.013 –

Temperature 18 11.4 14.2 11.7 11.8 0.620 0.014 0.962 none

Radioactive Waste Management Complex

RWMC M1SA 432956113030901 pH 8 8.32 8.72 8.39 8.43 0.129 -0.023 0.789 none

Specific conductance 8 277 288 283 283 3.77 -0.028 0.708 none

Temperature 8 12.0 13.3 12.6 12.7 0.396 0.352 0.048 +

RWMC M3S 433008113021801 pH 21 7.56 9.18 8.08 8.01 0.335 0.092 0.514 none

Specific conductance 21 348 376 369 368 6.61 0.048 0.454 none

Temperature 21 12.3 13.8 13.0 12.9 0.427 -0.167 0.148 none

RWMC M7S 433023113014801 pH 23 7.45 9.07 8.10 8.03 0.320 -0.107 0.399 none

Specific conductance 23 328 365 356 354 8.11 0.223 0.003 +

Temperature 23 12.4 14.0 13.3 13.4 0.430 -0.022 0.831 none
68 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. 

p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Radioactive Waste Management Complex—Continued

RWMC M11S 433058113010401 pH 15 7.47 8.30 7.87 7.93 0.245 -0.208 0.274 none

Specific conductance 15 266 345 299 306 21.7 -0.629 0.142 none

Temperature 15 14.1 17.4 16.5 16.3 0.792 0.097 0.754 none

RWMC M12S 433118112593401 pH 14 7.53 8.06 7.93 7.88 0.165 -0.038 0.782 none

Specific conductance 14 363 383 373 373 5.48 0.223 0.020

+

Temperature 14 11.8 13.1 12.2 12.3 0.392 -0.404 0.049

–

RWMC M13S 433037113002701 pH 15 7.51 8.33 8.12 8.05 0.236 -0.020 0.913 none

Specific conductance 15 253 267 261 261 3.26 -0.121 0.117 none

Temperature 15 13.9 16.2 14.7 14.9 0.784 -0.887 0.005

–

RWMC M14S 433052113025001 pH 15 7.62 8.08 7.90 7.89 0.126 -0.015 0.880 none

Specific conductance 15 370 389 379 379 6.06 -0.305 0.002

–

Temperature 15 12.5 13.4 13.1 13.1 0.252 -0.071 0.551 none

RWMC Production 433002113021701 pH 277 6.79 8.32 7.96 7.91 0.220 -0.200 0.000

–

Specific conductance 277 348 411 389 387 14.3 0.499 0.000

+

Temperature 277 12.0 15.1 12.9 12.9 0.378 -0.048 0.056 none

USGS 87 433013113024201 pH 63 7.63 8.23 8.08 8.04 0.098 0.015 0.572 none

Specific conductance 63 335 385 358 357 8.79 0.192 0.000

+

Temperature 63 11.7 15.8 14.0 13.9 0.703 -0.386 0.001

–

USGS 88 432940113030201 pH 63 7.23 8.60 8.30 8.22 0.237 -0.298 0.000

–

Specific conductance 63 549 605 580 581 9.81 -0.080 0.035

–

Temperature 63 9.80 14.7 13.7 13.7 0.824 -0.052 0.727 none

USGS 89 433005113032801 pH 63 7.95 8.95 8.32 8.32 0.178 0.015 0.745 none

Specific conductance 63 359 392 380 379 7.81 -0.008 0.863 none

Temperature 63 11.0 15.0 13.0 13.1 0.732 -0.269 0.028

–

USGS 120 432919113031501 pH 64 7.77 8.35 8.18 8.14 0.126 -0.115 0.001

–

Specific conductance 64 372 511 449 449 31.0 -0.586 0.000

–

Temperature 64 10.9 13.0 11.6 11.7 0.484 0.099 0.255 none

South of facilities

USGS 104 432856112560801 pH 59 7.54 8.52 8.03 7.98 0.159 -0.178 0.000

–

Specific conductance 59 305 333 327 325 7.27 0.123 0.018

+

Temperature 59 11.6 13.6 12.0 12.1 0.347 -0.081 0.211 none
Table 4 69

Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater 

wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

South of facilities—Continued

USGS 105 432703113001801 pH 33 7.61 8.23 8.02 8.01 0.137 -0.153 0.009 –

Specific conductance 33 363 390 380 379 5.41 -0.184 0.000 –

Temperature 33 13.2 14.5 13.7 13.7 0.294 -0.185 0.011 –

USGS 106 432959112593101 pH 42 7.49 8.09 7.95 7.89 0.154 -0.207 0.000 –

Specific conductance 42 382 410 399 397 7.33 0.029 0.495 none

Temperature 42 13.4 14.5 13.8 13.9 0.289 -0.138 0.004 –

USGS 108 432659112582601 pH 35 7.36 8.20 8.02 7.98 0.152 -0.152 0.014 –

Specific conductance 35 345 362 355 354 4.92 0.156 0.000 +

Temperature 35 12.5 13.5 13.0 13.0 0.225 -0.048 0.385 none

USGS 124 432307112583101 pH 30 7.66 8.08 7.93 7.91 0.112 -0.051 0.299 none

Specific conductance 30 356 374 368 367 5.01 -0.029 0.543 none

Temperature 30 13.0 14.2 13.5 13.5 0.233 0.139 0.020 +

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center

PW 1 433349112560701 pH 44 7.60 9.34 8.03 8.10 0.339 0.252 0.153 none

Specific conductance 44 814 1,545 1,197 1,139 178 -3.28 0.000 –

Temperature 44 9.60 18.0 14.9 14.8 2.14 -1.23 0.052 none

PW 2 433344112555601 pH 34 7.64 8.37 7.97 8.02 0.201 0.301 0.005 +

Specific conductance 34 860 1,340 1,180 1,166 120 -1.62 0.000 –

Temperature 34 12.5 19.5 14.5 14.8 1.64 -0.775 0.070 none

PW 3 433351112555701 pH 31 7.72 8.38 8.01 8.00 0.163 0.134 0.157 none

Specific conductance 31 857 1,452 1,240 1,210 149 -1.24 0.029 –

Temperature 31 11.2 19.5 15.6 15.7 1.79 0.147 0.787 none

PW 4 433348112554901 pH 51 6.78 8.55 7.97 7.90 0.335 -0.331 0.017 –

Specific conductance 52 627 1,447 1,218 1,169 209 -2.64 0.000 –

Temperature 52 9.10 17.0 14.0 13.8 1.82 -0.446 0.274 none

PW 5 433348112555701 pH 30 7.20 8.27 7.93 7.95 0.209 0.281 0.035 +

Specific conductance 30 737 1,473 1,195 1,198 176 -1.23 0.107 none

Temperature 30 9.80 19.0 16.4 15.6 2.21 1.26 0.084 none

PW 6 433353112562201 pH 30 7.94 10.5 9.50 9.23 0.689 0.233 0.586 none

Specific conductance 30 560 950 771 777 105 1.77 0.013 +

Temperature 30 9.00 14.1 11.3 11.4 1.38 -0.292 0.660 none
70 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. 

p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Perched groundwater wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 50 433419112560201 pH 40 7.63 8.50 7.96 7.97 0.177 0.115 0.092 none

Specific conductance 40 655 1,130 856 887 118 -1.68 0.000

–

Temperature 40 14.2 20.3 17.6 17.4 1.40 -0.134 0.596 none

Advanced Test Reactor Complex

CWP 1 433459112572601 pH 26 7.44 8.20 7.97 7.94 0.162 0.008 0.885 none

Specific conductance 26 372 1,110 561 715 289 0.163 0.887 none

Temperature 26 12.9 22.0 17.7 17.7 2.88 -1.11 0.005

–

CWP 2 433458112572401 pH 11 7.63 8.63 8.27 8.20 0.326 -0.113 0.712 none

Specific conductance 11 223 725 455 440 147 -2.15 0.405 none

Temperature 11 14.5 19.0 15.8 16.0 1.52 -1.27 0.030

–

CWP 3 433455112572501 pH 25 7.55 9.40 8.11 8.17 0.338 -0.131 0.233 none

Specific conductance 25 390 1,038 647 664 219 0.557 0.548 none

Temperature 25 11.6 21.5 17.3 16.8 2.46 -0.911 0.018

–

CWP 4 433454112572601 pH 14 7.91 9.40 8.47 8.47 0.471 0.131 0.618 none

Specific conductance 14 231 615 393 395 120 -2.32 0.077 none

Temperature 14 11.5 20.5 17.5 17.2 2.13 -0.145 0.823 none

CWP 5 433455112572901 pH 9 7.63 8.61 8.06 8.02 0.295 0.294 0.377 none

Specific conductance 9 327 980 491 588 248 -3.17 0.367 none

Temperature 9 12.0 21.7 17.5 17.4 3.18 0.534 0.758 none

CWP 8 433500112573001 pH 23 7.39 8.57 7.99 8.04 0.310 -0.097 0.371 none

Specific conductance 23 269 756 418 427 107 -0.356 0.586 none

Temperature 23 13.4 23.3 17.0 17.6 3.28 -0.877 0.070 none

PW 7 433446112574602 pH 14 7.36 8.55 7.96 7.91 0.344 -0.028 0.976 none

Specific conductance 14 379 670 520 529 72.4 -9.42 0.000

–

Temperature 14 10.0 15.0 11.0 11.6 1.74 -1.20 0.696 none

PW 8 433456112572001 pH 60 7.26 9.24 7.73 7.75 0.270 0.021 0.777 none

Specific conductance 60 281 914 750 716 140 0.099 0.854 none

Temperature 60 13.5 19.0 17.0 16.9 1.11 -0.401 0.009

–

PW 9 433500112575401 pH 59 7.24 8.19 7.73 7.72 0.130 -0.039 0.302 none

Specific conductance 59 475 663 610 612 34.4 -0.272 0.036

–

Temperature 59 11.0 19.0 16.5 16.2 1.25 0.002 0.990 none
Table 4 71

Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater 

wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

TRA A 13 433502112572802 pH 20 6.83 8.92 7.25 7.35 0.424 0.175 0.566 none

Specific conductance 20 405 944 733 712 156 -0.324 0.814 none

Temperature 20 14.0 21.0 17.1 16.9 1.93 -1.28 0.026 –

TRA A 77 433507112573801 pH 22 8.00 9.85 9.19 9.06 0.573 -1.35 0.021 –

Specific conductance 22 48.0 342 69.5 118 93.7 21.0 0.000 +

Temperature 21 12.5 25.0 18.5 18.2 3.23 -4.60 0.002 –

USGS 53 433503112573401 pH 14 6.89 7.72 7.64 7.53 0.257 -0.345 0.005 –

Specific conductance 14 320 835 637 619 161 0.119 0.908 none

Temperature 14 14.9 18.0 16.8 16.5 0.988 -0.587 0.006 –

USGS 54 433503112572801 pH 55 7.32 7.94 7.74 7.72 0.128 -0.136 0.000 –

Specific conductance 55 447 965 706 697 157 -0.574 0.278 none

Temperature 55 11.6 21.0 17.7 17.8 1.35 -0.531 0.004 –

USGS 55 433508112573001 pH 31 7.26 7.68 7.47 7.48 0.123 0.012 0.787 none

Specific conductance 31 445 849 635 634 77.0 -0.680 0.036 –

Temperature 31 12.2 15.5 13.5 13.7 0.871 0.776 0.000 +

USGS 56 433509112573501 pH 17 7.36 8.38 7.93 7.88 0.259 -0.085 0.432 none

Specific conductance 17 330 2,420 606 763 532 0.174 0.925 none

Temperature 17 13.1 17.5 15.9 15.6 1.33 -0.900 0.002 –

USGS 60 433456112571901 pH 44 7.28 7.95 7.74 7.71 0.126 -0.100 0.011 –

Specific conductance 44 451 885 681 687 123 -0.049 0.911 none

Temperature 44 14.0 19.0 16.1 16.2 1.14 -0.623 0.000 –

USGS 61 433453112571601 pH 38 7.54 7.99 7.85 7.82 0.109 -0.079 0.029 –

Specific conductance 38 477 718 622 621 66.7 0.090 0.751 none

Temperature 38 11.5 15.8 13.5 13.3 0.882 0.864 0.000 +

USGS 62 433446112570701 pH 38 7.28 8.99 7.73 7.72 0.262 -0.301 0.000 –

Specific conductance 38 486 882 751 724 106 0.443 0.274 none

Temperature 38 12.0 17.5 16.4 16.2 1.05 0.622 0.001 +

USGS 63 433455112574001 pH 38 7.32 7.85 7.71 7.67 0.121 -0.136 0.001 –

Specific conductance 38 467 843 764 715 103 0.178 0.651 none

Temperature 38 16.8 21.0 18.3 18.3 0.828 -0.213 0.055 none
72 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 4. Summary statistics and trend analyses for field measurements of pH, specific conductance, and water temperature for aquifer and perched groundwater wells after installation of dedicated pumps at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Field measurement: pH is in standard units; specific conductance is in microsiemens per centimeter at 25 degrees Celsius; temperature is in degrees Celsius. Slope: In percent change per year. 

p value: for linear trend over time. Trend: +, increasing; –, decreasing]

Local name

Site 

identifier

Field 

measurement

Sample 

size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

USGS 66 433436112564801 pH 27 6.59 8.23 7.68 7.68 0.295 -0.248 0.017

–

Specific conductance 27 517 860 710 698 74.9 -0.003 0.991 none

Temperature 27 11.0 14.8 12.4 12.4 1.02 0.259 0.220 none

USGS 68 433516112573901 pH 44 6.57 7.28 7.04 7.03 0.175 0.195 0.001

+

Specific conductance 44 1.60 7,010 5,555 4,871 1,800 -11.4 0.000

–

Temperature 44 11.0 17.7 14.0 14.0 1.08 0.503 0.004

+

USGS 69 433450112573001 pH 28 7.55 8.20 7.89 7.86 0.157 -0.198 0.000

–

Specific conductance 28 421 682 567 565 71.9 -1.16 0.000

–

Temperature 28 12.5 16.5 15.4 15.2 0.936 0.516 0.002

+

USGS 70 433504112571001 pH 38 7.40 8.03 7.76 7.73 0.144 -0.140 0.003

–

Specific conductance 38 445 808 661 661 81.2 -0.231 0.488 none

Temperature 38 12.6 16.0 13.5 13.5 0.655 0.014 0.907 none

USGS 71 433439112571501 pH 33 7.08 8.20 7.91 7.85 0.225 -0.002 0.977 none

Specific conductance 33 564 870 640 649 50.0 0.193 0.290 none

Temperature 33 10.0 16.8 11.8 12.0 1.59 -0.171 0.594 none

USGS 72 433519112574601 pH 25 6.64 7.97 7.68 7.68 0.259 -0.199 0.033

–

Specific conductance 25 458 860 604 593 87.3 -0.360 0.331 none

Temperature 25 13.6 19.5 15.7 15.7 1.59 -0.749 0.000

–

USGS 73 433502112575401 pH 37 7.40 8.22 7.81 7.81 0.196 -0.101 0.108 none

Specific conductance 37 432 1,030 569 578 98.2 0.329 0.370 none

Temperature 37 14.0 18.0 15.8 15.8 1.00 -0.368 0.020

–

USGS 78 433413112573501 pH 18 7.12 8.30 8.07 7.99 0.303 -0.122 0.469 none

Specific conductance 18 321 419 350 352 19.9 0.139 0.550 none

Temperature 18 9.10 12.7 10.2 10.5 1.12 -1.01 0.024

–

Radioactive Waste Management Complex

USGS 92 433000113025301 pH 22 7.63 8.70 8.02 8.02 0.265 -0.012 0.902 none

Specific conductance 22 770 1,080 961 957 66.6 0.058 0.789 none

Temperature 22 8.10 17.5 9.8 10.2 1.90 -0.815 0.067 none
Table 5 73

Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence 

so no trend is interpreted. Slope: In percent change per year. p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells

Idaho Nuclear Technology and Engineering Center

CPP 1 433433112560201 Tritium 75 0 51,700 1.2 NA NA -102 0.000 –

Strontium-90 73 0 26 NA NA NA NA NA NAC

CPP 2 433432112560801 Tritium 63 0 15,500 0.0 NA NA -179 0.103 none

Strontium-90 63 0 22 NA NA NA NA NA NAC

RIFLE RANGE 433243112591101 Tritium 14 420 3,250 1,070 NA NA -6.94 0.000 –

Strontium-90 13 0 5.0 NA NA NA NA NA NAC

USGS 20 433253112545901 Tritium 56 2,420 17,700 8,595 NA NA -6.00 0.000 –

Strontium-90 56 0 14 NA NA NA NA NA NAC

USGS 34 433334112565501 Tritium 54 0 11,600 3,723 NA NA -7.23 0.000 –

Strontium-90 52 0 11 3.3 NA NA -2.73 0.000 –

USGS 35 433339112565801 Tritium 54 0 21,500 4,476 NA NA -6.28 0.000 –

Strontium-90 53 0 16 NA NA NA NA NA NAC

USGS 36 433330112565201 Tritium 72 900 48,700 7,347 NA NA -13.9 0.000 –

Strontium-90 72 0 30 12 NA NA -5.56 0.000 –

USGS 37 433326112564801 Tritium 72 1,210 83,800 24,508 NA NA -13.2 0.000 –

Strontium-90 71 0 23 14 NA NA -5.09 0.000 –

USGS 38 433322112564301 Tritium 54 780 91,100 15,494 NA NA -15.4 0.000 –

Strontium-90 53 0 38 18 NA NA -3.43 0.000 –

USGS 39 433343112570001 Tritium 73 0 8,700 2,933 NA NA -4.00 0.000 –

Strontium-90 73 0 13 NA NA NA NA NA NAC

USGS 40 433411112561101 Tritium 91 750 425,000 8,753 NA NA -13.8 0.000 –

Strontium-90 89 0 210 33 NA NA -9.08 0.000 –

USGS 41 433409112561301 Tritium 56 0 136,000 4,459 NA NA -12.2 0.000 –

Strontium-90 53 5 100 18 NA NA -6.22 0.000 –

USGS 42 433404112561301 Tritium 56 0 210,000 3,415 NA NA -11.3 0.000 –

Strontium-90 54 0 129 14 NA NA -4.72 0.000 –

USGS 43 433415112561501 Tritium 54 600 200,000 6,442 NA NA -9.63 0.000 –

Strontium-90 53 0 39 1.6 NA NA -14.5 0.000 –

USGS 44 433409112562101 Tritium 55 0 396,000 89 NA NA -41.8 0.000 –

Strontium-90 54 0 180 3.7 NA NA -17.3 0.000 –

USGS 45 433402112561801 Tritium 56 0 189,000 1,695 NA NA -12.5 0.000 –

Strontium-90 55 0 64 1.1 NA NA -21.3 0.000 –

USGS 46 433407112561501 Tritium 55 0 365,000 2,831 NA NA -18.0 0.000 –

Strontium-90 53 0 140 14 NA NA -9.89 0.000 –
74 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence so no trend is interpreted. Slope: In percent change per year. 

p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 47 433407112560301 Tritium 79 340 292,000 8,436 NA NA -10.2 0.000

–

Strontium-90 77 6 128 54 NA NA -3.55 0.000

–

USGS 48 433401112560301 Tritium 57 0 77,700 5,879 NA NA -9.18 0.000

–

Strontium-90 55 0 56 21 NA NA -2.79 0.000

–

USGS 51 433350112560601 Tritium 53 4,130 39,800 17,684 NA NA -5.12 0.000

–

Strontium-90 53 0 15 NA NA NA NA NA NAC

USGS 52 433414112554201 Tritium 55 520 169,000 6,167 NA NA -11.63 0.000

–

Strontium-90 55 0 76 13 NA NA -8.09 0.000

–

USGS 57 433344112562601 Tritium 80 800 173,000 16,813 NA NA -15.04 0.000

–

Strontium-90 79 0 80 33 NA NA -7.06 0.000

–

USGS 59 433354112554701 Tritium 53 0 79,500 5,256 NA NA -12.82 0.000

–

Strontium-90 53 0 30 13 NA NA -2.69 0.000

–

USGS 67 433344112554101 Tritium 50 2,700 173,000 22,553 NA NA -11.80 0.000

–

Strontium-90 49 6 57 21 NA NA -5.17 0.000

–

USGS 77 433315112560301 Tritium 54 3,040 85,900 27,085 NA NA -9.81 0.000

–

Strontium-90 53 0 13 NA NA NA NA NA NAC

USGS 82 433401112551001 Tritium 72 0 40,400 250 NA NA -28.57 0.000

–

Strontium-90 72 0 14 NA NA NA NA NA NAC

USGS 84 433356112574201 Tritium 52 0 9,400 2,566 NA NA -4.79 0.000

–

Strontium-90 26 0 6.0 NA NA NA NA NA NAC

USGS 85 433246112571201 Tritium 55 1,220 31,100 9,712 NA NA -11.39 0.000

–

Strontium-90 55 0 12 NA NA NA NA NA NAC

USGS 111 433331112560501 Tritium 56 2,310 149,000 17,247 NA NA -13.22 0.000

–

Strontium-90 56 0 19 NA NA NA NA NA NAC

USGS 112 433314112563001 Tritium 76 770 80,700 14,697 NA NA -16.66 0.000

–

Strontium-90 76 6 41 25 NA NA -6.46 0.000

–

USGS 113 433314112561801 Tritium 74 1,720 96,000 14,815 NA NA -15.88 0.000

–

Strontium-90 73 0 27 14 NA NA -4.663 0.000

–

USGS 114 433318112555001 Tritium 74 6,240 34,100 21,613 NA NA -6.389 0.000

–

Strontium-90 74 0 14 NA NA NA NA NA NAC

USGS 115 433320112554101 Tritium 74 600 18,200 5,004 NA NA -11.20 0.000

–

Strontium-90 74 0 12 NA NA NA NA NA NAC

USGS 116 433331112553201 Tritium 73 1,200 21,600 6,481 NA NA -10.80 0.000

–

Strontium-90 73 0 10 NA NA NA NA NA NAC
Table 5 75

Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.—Continued[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence 

so no trend is interpreted. Slope: In percent change per year. p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 123 433352112561401 Tritium 33 2,610 31,400 12,358 NA NA -12.82 0.000 –

Strontium-90 33 0 41 16 NA NA -19.79 0.000 –

USGS 128 433250112565601 Tritium 11 1,050 3,400 2,004 NA NA -10.04 0.001 –

Strontium-90 11 0 7.8 5.1 NA NA -6.77 0.125 none

Advanced Test Reactor Complex

MTR TEST 433520112572601 Tritium 46 0 3,500 280 NA NA -14.6 0.001 –

TRA Disposal 433506112572301 Tritium 57 1,260 27,000 6,747 NA NA -4.17 0.000 –

Strontium-90 33 0 9.0 NA NA NA NA NA NAC

USGS 58 433500112572502 Tritium 49 380 16,100 2,489 NA NA -4.99 0.000 –

Strontium-90 31 0 400 NA NA NA NA NA NAC

USGS 65 433447112574501 Tritium 96 3,070 132,000 36,216 NA NA -12.4 0.000 –

Strontium-90 96 0 12 NA NA NA NA NA NAC

USGS 76 433425112573201 Tritium 77 0 8,800 2,600 NA NA -5.31 0.000 –

Strontium-90 77 0 21 NA NA NA NA NA NAC

USGS 79 433505112581901 Tritium 55 0 1,800 NA NA NA NA NA NAC

Central Facilities Area wells

CFA 1 433204112562001 Tritium 95 4,200 38,500 19,185 NA NA -6.73 0.000 –

Strontium-90 53 0 10 NA NA NA NA NA NAC

CFA 2 433144112563501 Tritium 91 3,770 29,100 15,486 NA NA -5.70 0.000 –

Strontium-90 51 0 9.0 NA NA NA NA NA NAC

CFA LF 3-9 433216112571001 Tritium 13 4,500 24,700 NA NA NA NA NA NAC

Strontium-90 13 0 5.0 NA NA NA NA NA NAC

CFA LF 2-10 433216112563301 Tritium 31 770 7,700 3,533 NA NA -8.04 0.000 –

Strontium-90 29 0 5.0 NA NA NA NA NA NAC

USGS 127 433058112572201 Tritium 18 0 540 NA NA NA NA NA NAC

Strontium-90 17 0 5.2 NA NA NA NA NA NAC

Radioactive Waste Management Complex

RWMC M3S 433008113021801 Tritium 21 640 1,400 NA NA NA NA NA NAC

Strontium-90 21 0 6.0 NA NA NA NA NA NAC

RWMC M7S 433023113014801 Tritium 21 0 1,700 1,144 NA NA -3.35 0.113 none

Strontium-90 21 0 6.0 NA NA NA NA NA NAC
76 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence so no trend is interpreted. Slope: In percent change per year. 

p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Radioactive waste management complex—Continued

RWMC M11S 433058113010401 Tritium 15 0 500 NA NA NA NA NA NAC

RWMC M12S 433118112593401 Tritium 14 670 1,100 NA NA NA NA NA NACRWMC M13S 433037113002701 Tritium 15 0 500 NA NA NA NA NA NACRWMC M14S 433052113025001 Tritium 15 600 1,310 1,318 NA NA -4.46 0.009

–

RWMC Production 433002113021701 Tritium 100 0 2,700 NA NA NA NA NA NAC

Strontium-90 96 0 12 NA NA NA NA NA NAC

USGS 87 433013113024201 Tritium 98 0 2,900 822 NA NA 0.513 0.004

+

Strontium-90 97 0 13 NA NA NA NA NA NAC

USGS 88 432940113030201 Tritium 96 0 1,800 NA NA NA NA NA NAC

Strontium-90 95 0 10 NA NA NA NA NA NAC

USGS 89 433005113032801 Tritium 98 0 1,100 NA NA NA NA NA NAC

Strontium-90 97 0 11 NA NA NA NA NA NAC

USGS 120 432919113031501 Tritium 69 0 1,100 NA NA NA NA NA NAC

Strontium-90 68 0 11 NA NA NA NA NA NAC

South of facilities

USGS 104 432856112560801 Tritium 90 0 2,200 1,242 NA NA -0.071 0.879 none

USGS 105 432703113001801 Tritium 62 0 1,690 15 NA NA -24.1 0.328 none

USGS 106 432959112593101 Tritium 76 0 5,300 2,048 NA NA -5.79 0.000

–

USGS 108 432659112582601 Tritium 54 0 1,700 5 NA NA -25.9 0.435 none

USGS 124 432307112583101 Tritium 31 0 640 NA NA NA NA NA NAC

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center

PW 1 433349112560701 Tritium 55 0 179,000 90.6 NA NA -75.3 0.000

–

Strontium-90 55 0 25 5.01 NA NA -21.3 0.000

–

PW 2 433344112555601 Tritium 44 0 180,000 1,034 NA NA -72.2 0.000

–

Strontium-90 44 0 17 0.847 NA NA -44.5 0.125 none

PW 3 433351112555701 Tritium 42 0 294,000 963 NA NA -67.6 0.000

–

Strontium-90 42 0 23 6.64 NA NA -16.7 0.000

–

PW 4 433348112554901 Tritium 61 0 141,000 1,292 NA NA -27.7 0.000

–

Strontium-90 61 0 16 2.48 NA NA -6.90 0.044

–

PW 5 433348112555701 Tritium 40 0 212,000 492 NA NA -69.2 0.000

–

Strontium-90 40 0 23 4.88 NA NA -23.4 0.001

–
Table 5 77

Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.—Continued[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence 

so no trend is interpreted. Slope: In percent change per year. p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center—Continued

PW 6 433353112562201 Tritium 41 5,900 34,300 19,166 NA NA -8.78 0.000 –

Strontium-90 41 0 12 0.026 NA NA -31.0 0.448 none

USGS 50 433419112560201 Tritium 75 15,000 230,000 93,663 NA NA -9.59 0.000 –

Strontium-90 74 95 550 273 NA NA -5.83 0.000 –

Advanced test reactor complex

CWP 1 433459112572601 Tritium 41 0 1,200 NA NA NA NA NA NAC

Strontium-90 25 0 7.3 NA NA NA NA NA NAC

CWP 3 433455112572501 Tritium 40 0 1,100 NA NA NA NA NA NAC

Strontium-90 24 0 10 NA NA NA NA NA NAC

CWP 4 433454112572601 Tritium 28 0 1,130 NA NA NA NA NA NAC

Strontium-90 13 0 6.2 NA NA NA NA NA NAC

CWP 5 433455112572901 Tritium 17 0 1,000 NA NA NA NA NA NAC

CWP 8 433500112573001 Tritium 37 0 1,400 NA NA NA NA NA NAC

Strontium-90 24 0 6.8 1.02 NA NA 4.45 0.539 none

PW 8 433456112572001 Tritium 70 0 359,000 1,825 NA NA -26.2 0.000 –

Strontium-90 55 0 23 12.3 NA NA -3.81 0.000 –

PW 9 433500112575401 Tritium 67 9,900 271,000 122,398 NA NA -13.5 0.000 –

Strontium-90 54 0 23 NA NA NA NA NA NAC

TRA A 13 433502112572802 Tritium 49 0 152,000 23.2 NA NA -103 0.000 –

Strontium-90 18 18.8 283 54.4 NA NA -15.3 0.000 –

TRA A 77 433507112573801 Tritium 60 0 5,570,000 937,465 NA NA -22.2 0.000 –

Strontium-90 19 1,000 38,800 2,746 NA NA 19.1 0.034 +

USGS 53 433503112573401 Tritium 32 320 2,010,000 452,225 NA NA -23.3 0.000 –

Strontium-90 14 17.9 139 83.6 NA NA -5.25 0.000 –

USGS 54 433503112572801 Tritium 90 0 1,860,000 3,251 NA NA -36.9 0.000 –

Strontium-90 51 29 170 82.8 NA NA -6.28 0.000 –

USGS 55 433508112573001 Tritium 53 0 495,000 12,535 NA NA -0.98 0.651 none

Strontium-90 32 0 65.1 17.2 NA NA 12.3 0.000 +

USGS 56 433509112573501 Tritium 35 1,400 1,910,000 542,473 NA NA -19.2 0.000 –

Strontium-90 17 0 74 33.0 NA NA 3.46 0.126 none
78 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 5. Summary statistics and trend test results for selected radiochemical constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1981–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Tritium and strontium-90 in picocuries per liter. Minimum: Value of 0 indicates a concentration and uncertainty that is less than three times the sample standard deviation or reporting level; other values represent smallest concentration without uncertainty that was greater than the reporting level. Trend: +, increasing; –, decreasing, NAC could not be calculated because of lack of convergence so no trend is interpreted. Slope: In percent change per year. 

p value: For linear trend over time. NA, value could not be calculated]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Perched groundwater wells—Continued

Advanced test reactor complex—Continued

USGS 60 433456112571901 Tritium 74 0 529,000 243 NA NA -24.4 0.000

–

Strontium-90 40 0 12.4 0.985 NA NA -0.69 0.908 none

USGS 61 433453112571601 Tritium 53 1,180 314,000 15,435 NA NA -15.3 0.000

–

Strontium-90 37 0 8.2 NA NA NA NA NA NAC

USGS 62 433446112570701 Tritium 53 0 253,000 690 NA NA -32.5 0.000

–

Strontium-90 36 0 10 NA NA NA NA NA NAC

USGS 63 433455112574001 Tritium 54 0 135,000 87.3 NA NA -38.4 0.000

–

Strontium-90 37 0 17 3.69 NA NA -5.99 0.000

–

USGS 66 433436112564801 Tritium 40 0 125,000 8,293 NA NA -20.0 0.000

–

Strontium-90 27 0 8.1 NA NA NA NA NA NAC

USGS 68 433516112573901 Tritium 80 0 4,500 NA NA NA NA NA NAC

Strontium-90 42 0 12 NA NA NA NA NA NAC

USGS 69 433450112573001 Tritium 43 0 1,100 NA NA NA NA NA NAC

Strontium-90 27 0 9.0 NA NA NA NA NA NAC

USGS 70 433504112571001 Tritium 56 500 382,000 27,748 NA NA -18.2 0.000

–

Strontium-90 38 2.6 63 42.1 NA NA -2.23 0.024

–

USGS 71 433439112571501 Tritium 45 380 112,000 8,009 NA NA -17.9 0.000

–

Strontium-90 31 0 9.0 NA NA NA NA NA NAC

USGS 72 433519112574601 Tritium 33 0 2,300 19.5 NA NA -1.27 0.881 none

Strontium-90 23 0 9.0 NA NA NA NA NA NAC

USGS 73 433502112575401 Tritium 55 1,660 491,000 59,970 NA NA -12.4 0.000

–

Strontium-90 37 0 9.0 NA NA NA NA NA NAC

USGS 78 433413112573501 Tritium 20 0 900 NA NA NA NA NA NAC

Strontium-90 18 0 5.5 NA NA NA NA NA NAC

Radioactive Waste Management Complex

USGS 92 433000113025301 Tritium 42 0 1,200 NA NA NA NA NA NAC

Strontium-90 40 0 10.2 NA NA NA NA NA NAC
Table 6 79

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells

Idaho Nuclear Technology and Engineering Center

CPP 1 Tritium 93 33 1972–2012 180 ± 60 in 2010 to 54,100 ± 800 in 1981

Strontium-90 88 10 1972–2012 1.4 ± 0.3 in 1986 to 28 ± 3 in 1974

Cesium-137 33 1 1982–2012 100 ± 30 in 1986

Plutonium-239, 240 30 0 1985–2012 N/A

Plutonium-238 30 0 1985–2012 N/A

Americium-241 30 0 1985–2012 N/A

Gross alpha 31 1 1982–2012 3.5 ± 1 in 2009

Gross beta 31 5 1982–2012 5.4 ± 1 in 2012 to 19 ± 1.7 in 2009

CPP 2 Tritium 79 9 1972–2012 600 ± 200 in 1978 to 16,700 ± 400 in 1981

Strontium-90 79 0 1972–2012 N/A

Rifle Range Tritium 14 14 1988–2012 720 ± 70 in 2011 to 3,700 ± 150 in 1988

Strontium-90 14 0 1988–2012 N/A

Cesium-137 13 0 1988–2012 N/A

USGS 20 Tritium 82 81 1966–2012 2,810 ± 130 in 2012 to 339,000 ± 4,000 in 1966

Strontium-90 67 0 1966–2012 N/A

USGS 34 Tritium 81 79 1966–2012 520 ± 150 in 2000 to 24,900 ± 700 in 1978

Strontium-90 65 15 1968–2012 2.4 ± 0.8 in 2003 to 33 ± 3 in 1979

Cesium-137 30 0 1969–2012 N/A

Plutonium-239, 240 29 0 1990–2012 N/A

Plutonium-238 29 0 1990–2012 N/A

Americium-241 29 0 1990–2012 N/A

Gross alpha 28 0 1994–2012 N/A

Gross beta 28 5 1994–2012 3.9 ± 1.1 in 2010 to 5.5 ± 1 in 2009

USGS 35 Tritium 71 67 1972–2012 470 ± 140 in 2000 to 24,200 ± 900 in 1987

Strontium-90 63 6 1972–2012 3.6 ± 0.8 in 1996 to 20 ± 2 in 1987

USGS 36 Tritium 100 100 1966–2012 1,240 ± 90 in 2012 to 91,000 ± 3,000 in 1968

Strontium-90 82 82 1973–2012 3.6 ± 0.6 in 2009 to 40 ± 4 in 1985

USGS 37 Tritium 106 106 1966–2012 1,000 ± 200 in 1977 to 160,000 ± 3,000 in 1968

Strontium-90 94 83 1968–2012 4.2 ± 0.7 in 2007 to 34 ± 3 in 1980

Cesium-137 27 0 1969–2012 N/A

Plutonium-239, 240 31 0 1982–2012 N/A

Plutonium-238 31 0 1982–2012 N/A

Americium-241 30 1 1982–2012 0.09 ± 0.03 in 1992

USGS 38 Tritium 81 81 1966–2012 1,020 ± 80 in 2012 to 264,000 ± 3,000 in 1966

Strontium-90 63 62 1968–2012 5.4 ± 0.7 in 2012 to 41.4 ± 1.3 in 2006

Cesium-137 30 0 1969–2012 N/A

Plutonium-239, 240 29 0 1990–2012 N/A

Plutonium-238 29 0 1990–2012 N/A

Americium-241 29 0 1990–2012 N/A

Gross alpha 28 0 1994–2012 N/A

Gross beta 28 4 1994–2012 9.4 ± 1.3 in 2010 to 16.5 ± 1.6 in 2008

USGS 39 Tritium 90 86 1972–2012 630 ± 150 in 2000 to 10,600 ± 400 in 1980

Strontium-90 83 0 1972–2012 N/A

USGS 40 Tritium 130 130 1972–2010 1,230 ± 160 in 2000 to 824,000 ± 4,000 in 1974

Strontium-90 123 123 1972–2010 9.2 ± 1.4 in 1997 to 410 ± 20 in 1979

Cesium-137 92 14 1978–2010 100 ± 30 in 1987 to 237 ± 45 in 1983
80 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 40 Plutonium-239, 240 77 4 1982–2010 0.036 ± 0.005 in 1982 to 5.5 ± 0.4 in 1987

—Continued Plutonium-238 77 7 1982–2010 0.11 ± 0.03 in 1983 to 1.31 ± 0.09 in 1983

Americium-241 67 1 1983–2010 1 ± 0.2 in 1987

USGS 41 Tritium 81 80 1972–2012 540 ± 160 in 1999 to 142,000 ± 2,000 in 1983

Strontium-90 69 69 1972–2012 7.7 ± 0.8 in 2009 to 200 ± 10 in 1980

USGS 42 Tritium 82 75 1972–2012 510 ± 140 in 1999 to 216,000 ± 2,000 in 1983

Strontium-90 70 66 1972–2012 3.3 ± 0.8 in 1999 to 150 ± 7 in 1983

USGS 43 Tritium 73 71 1972–2012 1,200 ± 200 in 1988 to 366,000 ± 2,000 in 1977

Strontium-90 63 21 1972–2012 2.3 ± 0.7 in 2003 to 127 ± 8 in 1977

Cesium-137 53 1 1978–2012 138 ± 41 in 1978

Plutonium-239, 240 26 0 1982–2012 N/A

Plutonium-238 27 0 1982–2012 N/A

Americium-241 25 0 1986–2012 N/A

USGS 44 Tritium 73 28 1967–2012 500 ± 100 in 1988 to 402,000 ± 2,000 in 1981

Strontium-90 64 44 1972–2012 2.2 ± 0.7 in 2003 to 210 ± 10 in 1981

Cesium-137 54 2 1981–2012 50 ± 14 in 2010 to 60 ± 15 in 1988

USGS 45 Tritium 74 57 1972–2012 410 ± 130 in 1998 to 195,000 ± 2,000 in 1981

Strontium-90 66 29 1972–2012 2 ± 0.6 in 2004 to 79 ± 5 in 1982

USGS 46 Tritium 72 68 1972–2012 320 ± 70 in 2010 to 371,000 ± 2,000 in 1981

Strontium-90 63 58 1972–2012 3.3 ± 0.7 in 2010 to 240 ± 10 in 1980

Cesium-137 52 0 1981–2012 N/A

USGS 47 Tritium 116 116 1972–2012 520 ± 60 in 2011 to 301,000 ± 3,000 in 1981

Strontium-90 104 104 1972–2012 15 ± 3 in 1986 to 152 ± 8 in 1981

Cesium-137 77 3 1978–2012 90 ± 30 in 1985 to 200 ± 50 in 1984

Plutonium-239, 240 34 2 1974–2012 0.003 ± 0.0007 in 1975 to 0.03 ± 0.008 in 1974

Plutonium-238 34 5 1974–2012 0.006 ± 0.001 in 1975 to 0.5 ± 0.06 in 1983

Americium-241 33 0 1974–2012 N/A

USGS 48 Tritium 81 81 1972–2012 950 ± 160 in 2,000 to 123,000 ± 2,000 in 1974

Strontium-90 72 72 1972–2012 9.9 ± 0.8 in 2000 to 62 ± 2 in 1989

USGS 51 Tritium 76 76 1972–2012 3,200 ± 400 in 1977 to 57,000 ± 2,000 in 1972

Strontium-90 69 5 1972–2012 2.5 ± 0.7 in 2008 to 20 ± 3 in 1973

USGS 52 Tritium 72 72 1972–2012 760 ± 80 in 2012 to 245,000 ± 2,000 in 1978

Strontium-90 65 65 1973–2012 3.9 ± 0.8 in 2010 to 104 ± 6 in 1980

USGS 57 Tritium 107 107 1972–2012 800 ± 200 in 1977 to 239,000 ± 2,000 in 1977

Strontium-90 102 102 1973–2012 7.5 ± 0.7 in 1998 to 105 ± 7 in 1979

Cesium-137 14 0 1997–2012 N/A

USGS 59 Tritium 78 78 1972–2012 500 ± 70 in 2012 to 81,900 ± 800 in 1981

Strontium-90 70 66 1972–2012 6 ± 2 in 1974 to 39 ± 3 in 1981

USGS 67 Tritium 67 67 1972–2012 3,120 ± 140 in 2011 to 462,000 ± 2,000 in 1977

Strontium-90 60 59 1972–2012 8.8 ± 0.6 in 2002 to 69 ± 4 in 1982

USGS 77 Tritium 79 79 1966–2012 3,490 ± 150 in 2011 to 241,000 ± 3,000 in 1966

Strontium-90 67 7 1968–2012 2 ± 0.5 in 1998 to 7 ± 2 in 1988

Cesium-137 28 0 1969–2012 N/A

Plutonium-239, 240 27 0 1990–2012 N/A

Plutonium-238 27 0 1990–2012 N/A
Table 6 81

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 77 Americium-241 27 0 1990–2012 N/A

—Continued Gross alpha 24 1 1995–2012 4 ± 1 in 2008 

Gross beta 24 5 1995–2012 8.4 ± 1 in 2009 to 14.6 ± 1.4 in 2008

USGS 82 Tritium 87 45 1972–2012 500 ± 130 in 1997 to 42,800 ± 800 in 1983

Strontium-90 80 3 1972–2012 2.4 ± 0.7 in 2008 to 8 ± 2 in 1991

USGS 84 Tritium 69 66 1972–2012 540 ± 60 in 2011 to 12,000 ± 2,000 in 1973

Strontium-90 26 0 1994–2012 N/A

Cesium-137 28 0 1981–2012 N/A

Plutonium-239, 240 28 0 1994–2012 N/A

Plutonium-238 28 0 1994–2012 N/A

Americium-241 28 0 1994–2012 N/A

Gross alpha 28 1 1994–2012 4.2 ± 1 in 2008 

Gross beta 28 12 1994–2012 2.4 ± 0.8 in 2012 to 4.4 ± 0.59 in 2001

USGS 85 Tritium 81 81 1966–2012 1,520 ± 100 in 2012 to 55,900 ± 900 in 1978

Strontium-90 68 29 1968–2012 2.1 ± 0.6 in 1998 to 9 ± 3 in 1977

USGS 111 Tritium 56 56 1985–2012 2,700 ± 130 in 2012 to 164,000 ± 5,000 in 1986

Strontium-90 56 2 1985–2012 11 ± 2 in 1987 to 28 ± 3 in 1989

USGS 112 Tritium 76 76 1985–2012 1,010 ± 80 in 2012 to 88,200 ± 2,500 in 1986

Strontium-90 76 76 1985–2012 8.6 ± 0.8 in 2006 to 53 ± 4 in 1987

USGS 113 Tritium 74 74 1985–2012 2,050 ± 110 in 2012 to 108,000 ± 4,000 in 1986

Strontium-90 73 72 1985–2012 5.9 ± 0.8 in 2010 to 30 ± 3 in 1986

Cesium-137 16 0 1994–2012 N/A

USGS 114 Tritium 74 74 1985–2012 7,020 ± 260 in 2011 to 37,700 ± 1,200 in 1986

Strontium-90 74 2 1985–2012 2.1 ± 0.6 in 2003 to 8 ± 2 in 1987

USGS 115 Tritium 74 74 1985–2012 1,150 ± 80 in 2008 to 20,600 ± 800 in 1985

Strontium-90 74 1 1985–2012 2.5 ± 0.7 in 2008

USGS 116 Tritium 73 73 1985–2012 1,800 ± 200 in 2002 to 24,300 ± 900 in 1985

Strontium-90 73 0 1985–2012 N/A

USGS 123 Tritium 33 33 1991–2012 2,940 ± 110 in 2012 to 33,800 ± 800 in 1993

Strontium-90 33 25 1991–2012 2.9 ± 0.7 in 2005 to 53 ± 4 in 1991

USGS 128 Tritium 11 11 2001–2012 1,290 ± 80 in 2012 to 4,300 ± 300 in 2001

Strontium-90 11 11 2001–2012 3.5 ± 0.7 in 2011 to 9.6 ± 0.8 in 2004

Advanced Test Reactor Complex

MTR Test Tritium 58 21 1972–2012 420 ± 140 in 2007 to 4,400 ± 300 in 1991

TRA Disposal Tritium 57 57 1985–2012 1,530 ± 90 in 2011 to 29,100 ± 700 in 1992

Strontium-90 33 1 1987–2012 4.1 ± 0.9 in 2004

Cesium-137 50 0 1986–2012 N/A

USGS 58 Tritium 87 82 1962–2012 590 ± 70 in 2012 to 140,000 ± 20,000 in 1967

Strontium-90 40 1 1969–2012 155 ± 8 in 1980

Cesium-137 37 0 1969–2012 N/A

USGS 65 Tritium 133 133 1969–2012 3,550 ± 160 in 2012 to 206,000 ± 3,000 in 1972

Strontium-90 119 4 1972–2012 2.1 ± 0.7 in 2000 to 18 ± 3 in 1976

Cesium-137 89 1 1981–2012 120 ± 20 in 1988

Plutonium-239, 240 31 0 1982–2012 N/A

Plutonium-238 32 0 1982–2012 N/A
82 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells—Continued

Advanced Test Reactor Complex—Continued

USGS 65 Americium-241 31 0 1984–2012 N/A

—Continued Gross alpha 29 0 1994–2012 N/A

Gross beta 29 6 1994–2012 3.2 ± 0.55 in 2007 to 6.8 ± 1.1 in 2009

USGS 76 Tritium 110 107 1972–2012 570 ± 70 in 2012 to 8,000 ± 2,000 in 1972

Strontium-90 94 4 1975–2012 6 ± 2 in 1975 to 30 ± 3 in 1987

Cesium-137 72 1 1981–2012 57.7 ± 17 in 1982

USGS 79 Tritium 80 10 1972–2012 420 ± 140 in 2000 to 900 ± 300 in 1987

Central Facilities Area

CFA 1 Tritium 138 138 1966–2012 4,770 ± 190 in 2012 to 118,000 ± 2,000 in 1968

Strontium-90 59 2 1968–2012 1.9 ± 0.6 in 2012 to 8 ± 2 in 1979

CFA 2 Tritium 126 126 1966–2012 4,280 ± 170 in 2011 to 76,000 ± 2,000 in 1974

Strontium-90 55 0 1968–2012 N/A

CFA LF 2-10 Tritium 31 31 1993–2012 1,220 ± 150 in 2007 to 9,200 ± 500 in 1993

Strontium-90 29 2 1993–2012 2.1 ± 0.7 in 2003 to 2.4 ± 0.7 in 2008

Cesium-137 30 0 1994–2012 N/A

Gross alpha 29 1 1994–2012 3 ± 1in 2009

Gross beta 29 5 1994–2012 3.7 ± 1 in 2008 to 5.9±1 in 2009

CFA LF 3-9 Tritium 13 13 1993–2007 5,400 ± 300 in 2007 to 28,000 ± 1,100 in 1993

Strontium-90 13 2 1993–2007 2.5 ± 0.8 in 2005 to 2.6 ± 0.7 in 1995

USGS 127 Tritium 18 0 2000–2012 N/A

Strontium-90 17 1 2000–2012 3.1 ± 0.7 in 2003

Cesium-137 18 0 2000–2012 N/A

Gross alpha 18 1 2000–2012 3.5 ± 1 in 2009

Gross beta 18 5 2000–2012 3.4 ± 0.9 in 2007 to 4.5 ± 0.68 in 2005

Radioactive Waste Management Complex

RWMC M1S Plutonium-239, 240 22 1 1993–2012 0.006 ± .001 in 2001

Plutonium-238 22 0 1993–2012 N/A

Americium-241 22 0 1993–2012 N/A

RWMC M3S Tritium 21 21 1993–2012 900 ± 70 in 2011 to 2,000 ± 300 in 1996

Strontium-90 21 0 1993–2012 N/A

RWMC M7S Tritium 21 21 1993–2012 760 ± 70 in 2011 to 1,600 ± 200 in 1998

Strontium-90 21 1 1993–2012 2.3 ± 0.7 in 2008

RWMC M11S Tritium 15 0 2000–2012 N/A

Cesium-137 14 1 2000–2012 27 ± 9 in 2012

Gross alpha 15 1 2000–2012 2.7 ± 0.8 in 2008

Gross beta 15 8 2000–2012 2.5 ± 0.8 in 2009 to 5.6 ± 0.8 in 2010

RWMC M12S Tritium 14 14 2000–2012 890 ± 70 in 2012 to 1,700 ± 200 in 2001

Cesium-137 14 1 2000–2012 30 ± 10 in 2004

Gross alpha 14 1 2000–2012 3.2 ± 0.9 in 2008

Gross beta 14 6 2000–2012 3.5 ± 0.8 in 2009 to 4.9 ± 0.8 in 2010

RWMC M13S Tritium 15 0 2000–2012 N/A

Cesium-137 15 0 2000–2012 N/A

Gross alpha 15 1 2000–2012 2.3 ± 0.7 in 2008

Gross beta 15 6 2000–2012 2.8 ± 0.8 in 2009 to 4.44 ± 0.765 in 2001
Table 6 83

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells—Continued

Radioactive Waste Management Complex—Continued

RWMC M14S Tritium 15 15 2000–2012 910 ± 70 in 2012 to 1,800 ± 200 in 2001

Cesium-137 15 0 2000–2012 N/A

Gross alpha 15 1 2000–2012 3.2 ± 0.9 in 2008

Gross beta 15 8 2000–2012 2.8 ± 0.8 in 2009 to 5.6 ± 1in 2008

RWMC

production

Tritium 113 113 1975–2012 780 ± 70 in 2011 to 2,300 ± 400 in 1988

Strontium-90 106 1 1977–2012 6 ± 2 in 1987

Cesium-137 63 1 1977–2012 34 ± 11 in 2012

Plutonium-239, 240 62 0 1975–2012 N/A

Plutonium-238 65 0 1975–2012 N/A

Americium-241 65 1 1975–2012 0.003 ± 0.001 in 2001

USGS 87 Tritium 148 111 1972–2012 600 ± 200 in 1976 to 7,000 ± 2,000 in 1973

Strontium-90 140 9 1972–2012 2.8 ± 0.7 in 2003 to 23 ± 4 in 1987

Cesium-137 124 4 1972–2012 30 ± 10 in 1974 to 90 ± 30 in 1986

Plutonium-239, 240 117 1 1972–2012 0.03 ± 0.008 in 1974

Plutonium-238 120 3 1972–2012 0.029 ± 0.008 in 1973 to 0.04 ± 0.009 in 1973

Americium-241 119 4 1972–2012 0.04 ± 0.01 in 1972 to 0.3 ± 0.02 in 1973

Gross alpha 30 0 1972–2012 N/A

Gross beta 29 10 1994–2012 3.3 ± 0.9 in 2009 to 4.6 ± 0.9 in 2012

USGS 88 Tritium 149 2 1972–2011 900 ± 300 in 1986 to 6,000 ± 2,000 in 1973

Strontium-90 141 7 1972–2011 6 ± 2 in 1979 to 58 ± 4 in 1973

Cesium-137 124 2 1972–2011 24 ± 5 in 1972 to 30 ± 9 in 1987

Plutonium-239, 240 119 2 1972–2011 0.04 ± 0.009 in 1974 to 0.04 ± 0.01 in 1976

USGS 88 Plutonium-238 122 5 1972–2011 0.028 ± 0.007 in 1973 to 0.27 ± 0.03 in 1973

Americium-241 121 8 1972–2011 0.02 ± 0.006 in 1982 to 0.13 ± 0.02 in 1973

USGS 89 Tritium 152 2 1972–2012 1,000 ± 200 in 1977 to 10,000 ± 2,000 in 1973

Strontium-90 144 4 1972–2012 2.5 ± 0.7 in 2008 to 6 ± 2 in 1975

Cesium-137 102 5 1981–2012 24 ± 7 in 1976 to 90 ± 10 in 1972

Plutonium-239, 240 99 5 1972–2012 0.03 ± 0.01 in 1974 to 0.29 ± 0.02 in 1973

Plutonium-238 101 3 1972–2012 0.021 ± 0.006 in 1973 to 0.04 ± 0.01 in 1974

Americium-241 102 7 1972–2012 0.011 ± 0.002 in 1973 to 5 ± 1 in 1972

USGS 120 Tritium 69 3 1987–2012 240 ± 60 in 2009 to 290 ± 60 in 2010

Strontium-90 68 0 1987–2012 N/A

Cesium-137 67 0 1987–2012 N/A

Plutonium-239, 240 62 0 1989–2012 N/A

Plutonium-238 65 0 1987–2012 N/A

Americium-241 65 1 1987–2012 0.06 ± 0.02 in 1993

Gross alpha 27 1 1994–2012 3.7 ± 1 in 2008

Gross beta 27 9 1994–2012 2.7 ± 0.7 in 2009 to 7 ± 1.1 in 2008

South of facilities

USGS 104 Tritium 91 79 1980–2012 740 ± 110 in 2007 to 2,400 ± 400 in 1984

USGS 105 Tritium 63 11 1980–2007 150 ± 50 in 1999 to 1,960 ± 90 in 1983

Cesium-137 23 0 1987–2007 N/A

Gross alpha 23 0 1987–2007 N/A

Gross beta 23 5 1987–2007 4 ± 1 in 2004 to 4.4 ± 0.65 in 1998

USGS 106 Tritium 78 78 1980–2012 500 ± 60 in 2011 to 6,500 ± 400 in 1983
84 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Aquifer wells—Continued

South of facilities—Continued

USGS 108 Tritium 55 1 1980–2008 1,800 ± 100 in 1983

Cesium-137 24 0 1989–2008 N/A

Gross alpha 23 0 1994–2008 N/A

Gross beta 23 8 1994–2008 4 ± 1 for several to 4.46 ± 0.83 in 2001

USGS 124 Tritium 31 6 1994–2012 180 ± 60 in 2000 to 340 ± 80 in 1995

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center

PW 1 Tritium 55 25 1987–2002 600 ± 200 in 1994 to 194,000 ± 5,000 in 1988

Strontium-90 55 30 1987–2002 2.6 ± 0.8 in several to 34 ± 3 in 1988

Cesium-137 14 0 1987–2002 N/A

PW 2 Tritium 44 34 1987–2002 390 ± 130 in 1998 to 195,000 ± 5,000 in 1988

Strontium-90 44 17 1987–2002 2.1 ± 0.5 in 1998 to 16 ± 2 in 1988

Cesium-137 15 0 1987–2002 N/A

PW 3 Tritium 42 26 1987–2002 450 ± 140 in 2002 to 318,000 ± 8,000 in 1988

Strontium-90 42 30 1987–2002 2 ± 0.5 in 1998 to 22 ± 2 in 1988

Cesium-137 15 0 1987–2002 N/A

PW 4 Tritium 61 48 1987–2006 480 ± 140 in 1999 to 14,900 ± 500 in 1988

Strontium-90 61 43 1987–2006 1.8 ± 0.6 in 1997 to 18 ± 2 in 1988

Cesium-137 19 0 1987–2006 N/A

PW 5 Tritium 40 21 1987–2002 600 ± 200 in 1992 to 230,000 ± 6,000 in 1988

Strontium-90 40 26 1987–2002 2.5 ± 0.8 in 2000 to 25 ± 3 in 1989

Cesium-137 15 0 1987–2002 N/A

PW 6 Tritium 41 41 1987–2000 7,100 ± 400 in 1997 to 36,700 ± 800 in 1988

Strontium-90 41 3 1987–2000 5.7 ± 1.5 in 1997 to 21 ± 3 in 1990

Cesium-137 10 0 1987–2000 N/A

USGS 50 Tritium 112 112 1967–2008 15,900 ± 300 in 2008 to 2,526,000 ± 10,000 in

1968

Strontium-90 107 107 1972–2008 101 ± 2 in 2007 to 820 ± 30 in 1972

Cesium-137 69 1 1981–2008 26.3 ± 6.8 in 1981

Advanced Test Reactor Complex

CWP 1 Tritium 41 0 1982–2012 N/A

Strontium-90 25 2 1989–2012 2 ± 0.6 in 2004 to 3.1 ± 0.7 in 1999

CWP 2 Tritium 21 0 1983–2001 N/A

Strontium-90 9 0 1990–2001 N/A

CWP 3 Tritium 40 0 1982–2012 N/A

Strontium-90 24 1 1989–2012 3 ± 0.7 in 2011

CWP 4 Tritium 28 0 1982–2010 N/A

Strontium-90 13 0 1989–2010 N/A

CWP 5 Tritium 17 0 1982–2001 N/A

Strontium-90 8 0 1989–2001 N/A

CWP 8 Tritium 37 1 1982–2012 800 ± 200 in 1988

Strontium-90 24 2 1989–2012 5.4 ± 0.8 in 2009 to 6.4 ± 1.2 in 2003

PW 8 Tritium 70 61 1987–2012 240 ± 70 in 2009 to 377,000 ± 6,000 in 1992

Strontium-90 55 53 1989–2012 2.5 ± 0.7 in 2003 to 24.7 ± 1.4 in 1995

Cesium-137 26 0 1987–2012 N/A
Table 6 85

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

PW 9 Tritium 67 67 1987–2012 10,500 ± 200 in 2012 to 295,000 ± 8,000 in 1987

Strontium-90 54 4 1989–2012 2.1 ± 0.7 in 2008 to 14 ± 3 in 1990

Cesium-137 26 0 1987–2012 N/A

TRA A 13 Tritium 78 43 1972–2001 900 ± 200 in 1983 to 718,000 ± 6,000 in 1972

Strontium-90 24 24 1972–2001 22.1 ± 1.1 in 2001 to 339 ± 4 in 1972

Cesium-137 29 1 1980–2001 1,000 ± 200 in 1972

TRA A 77 Tritium 92 92 1972–1997 560 ± 130 in 1997 to 5,630,000 ± 20,000 in 1983

Strontium-90 25 25 1972–1997 170 ± 10 in 1972 to 43,000 ± 1,400 in 1995

Cesium-137 31 28 1972–1997 180 ± 50 in 1933 to 42,300 ± 1,800 in 1996

USGS 53 Tritium 53 53 1968–2012 530 ± 70 in 2012 to 2,040,000 ± 10,000 in 1983

Strontium-90 19 18 1972–2012 20.9 ± 1 in 2011 to 368 ± 2.5 in 1972

Cesium-137 19 1 1980–2012 118 ± 37 in 1983

USGS 54 Tritium 147 130 1962–2012 180 ± 60 in 2009 to 1,890,000 ± 10,000 in 1983

Strontium-90 58 58 1972–2012 6 ± 1 in 1980 to 817 ± 8 in 1972

Cesium-137 38 0 1980–2012 N/A

USGS 55 Tritium 78 78 1962–2012 900 ± 200 in 1994 to 537,000 ± 14,000 in 1986

Strontium-90 37 36 1972–2012 6 ± 2 in 1993 to 70.5 ± 1.8 in 2006

Cesium-137 30 0 1981–2012 N/A

USGS 56 Tritium 61 60 1962–2012 1,670 ± 90 in 2012 to 1,970,000 ± 20,000 in 1983

Strontium-90 21 19 1972–2012 0.011 ± 0.001 in 1972 to 89 ± 5 in 1991

Cesium-137 22 0 1980–2012 N/A

USGS 60 Tritium 109 71 1966–2011 410 ± 130 in 1997 to 973,000 ± 7,000 in 1970

Strontium-90 46 21 1970–2011 0.014 ± 0.001 in 1972 to 11 ± 3 in 1976

Cesium-137 34 0 1970–2011 N/A

USGS 61 Tritium 71 71 1966–2011 1,480 ± 100 in 2012 to 546,000 ± 5,000 in 1971

Strontium-90 41 4 1972–2012 1.6 ± 0.5 in 1998 to 180 ± 10 in 1973

Cesium-137 32 1 1982–2012 12 ± 4 in 2010

USGS 62 Tritium 78 59 1962–2012 300 ± 100 in 2000 to 692,000 ± 5,000 in 1969

Strontium-90 39 17 1972–2012 2.2 ± 0.7 in 2003 to 4.4 ± 0.7 in 2011

Cesium-137 33 0 1980–2012 N/A

USGS 63 Tritium 71 40 1962–2012 180 ± 60 in 2006 to 673,000 ± 5,000 in 1969

Strontium-90 42 25 1970–2012 2.1 ± 0.6 in 2002 to 13 ± 2 in 1991

Cesium-137 32 1 1970–2012 32 ± 10 in 2008

USGS 66 Tritium 60 60 1966–2012 240 ± 60 in 2011 to 258,000 ± 3,000 in 1974

Strontium-90 30 1 1972–2012 3.5 ± 0.9 in 2004

Cesium-137 21 1 1980–2012 31 ± 0.5 in 1980

USGS 68 Tritium 108 5 1972–2012 190 ± 60 in 2005 to 47,400 ± 900 in 1979

Strontium-90 46 2 1972–2012 4 ± 1 in 1972 to 6 ± 2 in 1991

Cesium-137 37 2 1972–2012 27 ± 9 in 2012 to 310±90 in 1972

Gross alpha 18 0 1999–2012 N/A

Gross beta 18 7 1999–2012 3.2 ± 0.2 in 2007 to 8.5 ± 1.1 in 2012

USGS 69 Tritium 65 23 1967–2012 230 ± 60 in 2012 to 260,000 ± 20,000 in 1967

Strontium-90 31 2 1970–2012 2.4 ± 0.8 in 2004 to 7 ± 2 in 1976

Cesium-137 22 0 1970–2012 N/A
86 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012

Table 6. Summary of water-quality results for selected radiochemical constituents in water from aquifer and perched groundwater 

wells at and near the Idaho National Laboratory, Idaho.—Continued

[See figures 2 and 3 for well locations. Data available at http://waterdata.usgs.gov/nwis. Local name: Local well identifier used in this study. Constituent: 

Concentrations in picocuries per liter. Concentration ranges: For values equal to or greater than the reporting level (three sample standard deviations) and year 

concentration was sampled. Uncertainty is one sample standard deviation; ±, plus or minus; N/A, no values greater than reporting level]

Local 

name

Constituent Number of 

samples

Number greater than 

reporting level

Period of 

record

Concentration range greater 

than reporting level

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

USGS 70 Tritium 84 84 1962–2012 710 ± 70 in 2011 to 900,000 ± 6,000 in 1970

Strontium-90 41 41 1972–2012 5 ± 0.8 in 2006 to 78 ± 5 in 1989

Cesium-137 34 1 1981–2012 27 ± 9 in 2012

USGS 71 Tritium 66 66 1962–2012 590 ± 70 in 2011 to 338,000 ± 3,000 in 1972

Strontium-90 34 1 1970–2012 3.7 ± 0.8 in 2004

Cesium-137 27 0 1970–2012 N/A

USGS 72 Tritium 37 3 1974–2012 450 ± 70 in 2012 to 2,900 ± 200 in 1989

Strontium-90 26 1 1974–2012 17 ± 3 in 1974

Cesium-137 21 0 1984–2012 N/A

Gross alpha 12 0 1999–2012 N/A

Gross beta 12 5 1999–2012 3.4 ± 1 in 2008 to 5.6 ± 1 in 2009

USGS 73 Tritium 86 85 1962–2012 1,930 ± 90 in 2012 to 533,000 ± 14,000 in 1986

Strontium-90 40 3 1970–2012 2.1 ± 0.7 in 2011 to 4.4 ± 0.9 in 2004

Cesium-137 35 0 1970–2012 N/A

USGS 78 Tritium 24 0 1972–2012 N/A

Strontium-90 19 2 1972–2012 2.6 ± 0.7 in 2008 to 3.1 ± 0.8 in 2004

Cesium-137 11 0 1986–2012 N/A

Radioactive Waste Management Complex

USGS 92 Tritium 49 10 1972–2012 300 ± 100 in 2000 to 580 ± 70 in 2012

Strontium-90 47 2 1972–2012 7.2 ± 1 in 1998 to 9 ± 2 in 1980

Cesium-137 48 3 1972–2012 60 ± 10 in 1972 to 200 ± 10 in 1972

Plutonium-239, 240 43 0 1972–2012 N/A

Plutonium-238 47 2 1972–2012 0.025 ± 0.008 in 1974 to 0.39 ± 0.05 in 1994

Americium-241 45 2 1974–2012 0.041 ± 0.012 in 1976 to 0.14 ± 0.04 in 1992
Table 7 87

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells

Idaho Nuclear Technology and Engineering Center

CPP 1 433433112560201 Chloride 46 12.6 23.0 16.4 16.4 2.21 -1.39 0.000 –

Sodium 46 7.60 9.76 8.20 8.26 0.410 0.123 0.264 none

Sulfate 32 21.2 29.0 23.6 23.7 1.58 -0.613 0.002 –

Nitrate plus nitrite as N 35 0.779 1.23 0.961 0.994 0.118 -0.907 0.002 –

Orthophosphate as P 35 0.010 0.035 0.021 0.022 0.005 0.951 0.134 none

Fluoride 32 0.100 0.300 0.229 0.229 0.039 1.02 0.069 none

Chromium 42 0.000 14.0 5.84 NA NA 1.30 0.036 +

Total organic carbon 18 0.000 4.58 0.430 NA NA -0.768 0.832 none

CPP 2 433432112560801 Chloride 39 10.3 20.0 15.4 15.2 2.30 -1.56 0.000 –

Sodium 39 7.10 9.00 7.83 7.85 0.387 0.100 0.382 none

Sulfate 9 17.2 29.0 24.0 24.1 3.12 -3.58 0.001 –

Nitrate plus nitrite as N 22 0.732 1.50 0.870 0.910 0.155 -1.13 0.002 –

Orthophosphate as P 22 0.010 0.064 0.020 0.024 0.011 2.65 0.004 +

Chromium 35 0.000 14.0 5.45 NA NA 0.942 0.075 none

RIFLE RANGE 433243112591101 Chloride 13 8.78 42.4 28.8 26.0 12.4 13.2 0.000 +

Sodium 12 8.23 16.4 13.1 12.7 3.17 6.95 0.001 +

Sulfate 13 30.2 33.1 31.2 31.5 1.02 -0.638 0.011 –

Chromium 13 5.01 20.5 10.1 11.7 4.43 -9.02 0.000 –

USGS 20 433253112545901 Chloride 39 21.0 35.5 27.7 26.9 3.23 1.48 0.000 +

Sodium 26 7.80 9.56 8.47 8.53 0.438 0.501 0.000 +

Sulfate 20 17.0 23.0 19.9 19.8 1.42 -0.007 0.978 none

Nitrate plus nitrite as N 26 0.420 1.43 1.10 1.14 0.216 1.89 0.001 +

Orthophosphate as P 26 0.000 0.025 0.012 NA NA 2.76 0.010 +

USGS 34 433334112565501 Chloride 37 9.33 25.0 14.0 15.0 4.40 -2.89 0.000 –

Sodium 33 7.73 15.5 9.44 9.82 1.57 -1.11 0.002 –

Sulfate 29 21.3 44.8 29.0 32.5 8.06 3.14 0.000 +

Nitrate plus nitrite as N 33 0.570 1.50 1.04 1.03 0.192 -0.701 0.196 none

Fluoride 28 0.184 0.300 0.202 0.216 0.026 -0.360 0.329 none

Orthophosphate as P 33 0.000 0.033 0.020 NA NA 2.47 0.000 +

Chromium 29 0.000 30.3 17.1 NA NA 4.05 0.002 +

Total organic carbon 18 0.000 2.10 0.535 NA NA -3.99 0.328 none
88 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 35 433339112565801 Chloride 37 6.75 32.0 12.0 14.8 6.39 -3.61 0.000

–

Sodium 24 7.02 18.0 9.11 9.71 2.47 -1.69 0.002

–

Sulfate 19 23.8 46.5 40.1 38.0 8.16 2.76 0.000

+

Nitrate plus nitrite as N 24 0.658 2.20 1.04 1.12 0.353 -2.05 0.004

–

Orthophosphate as P 24 0.016 0.030 0.024 0.024 0.005 -0.044 0.942 none

USGS 36 433330112565201 Chloride 55 13.0 81.3 41.0 41.8 20.8 -7.73 0.000

–

Sodium 24 9.29 26.6 16.1 16.8 6.29 -4.91 0.000

–

Sulfate 20 23.9 41.2 29.3 32.5 6.42 2.26 0.000

+

Nitrate plus nitrite as N 25 0.978 3.00 1.60 1.74 0.682 -5.23 0.000

–

Orthophosphate as P 25 0.000 0.040 0.024 NA NA 0.258 0.681 none

USGS 37 433326112564801 Chloride 39 18.7 147 78.0 79.7 44.8 -8.46 0.000

–

Sodium 23 14.4 49.5 32.0 31.3 13.0 -5.49 0.000

–

Sulfate 19 26.3 39.4 31.0 33.0 4.57 1.73 0.000

+

Nitrate plus nitrite as N 24 1.12 3.40 2.76 2.22 0.904 -5.93 0.000

–

Ammonia 24 0.000 0.140 0.009 NA NA -6.97 0.127 none

Orthophosphate as P 24 0.000 0.230 0.019 NA NA -1.48 0.394 none

USGS 38 433322112564301 Chloride 37 15.4 192 110 108 62.2 -11.6 0.000

–

Sodium 33 11.7 93.0 46.7 45.8 23.1 -8.63 0.000

–

Sulfate 29 25.0 38.0 30.0 31.2 3.88 0.844 0.024

+

Nitrate plus nitrite as N 32 0.190 3.60 2.64 2.24 0.970 -3.96 0.020

–

Fluoride 29 0.100 0.300 0.228 0.232 0.041 1.36 0.032

+

Orthophosphate as P 32 0.000 0.032 0.019 NA NA 2.18 0.013

+

Chromium 29 0.000 19.4 9.85 NA NA 6.39 0.000

+

Total organic carbon 18 0.000 1.74 0.418 NA NA 0.282 0.940 none

USGS 39 433343112570001 Chloride 56 6.46 68.0 11.2 11.9 7.87 -1.12 0.128 none

Sodium 23 6.66 9.48 8.24 8.21 0.775 0.579 0.026

+

Sulfate 18 23.3 45.9 40.1 37.7 8.08 2.47 0.000

+

Nitrate plus nitrite as N 23 0.624 1.06 0.954 0.908 0.125 0.674 0.104 none

Orthophosphate as P 23 0.014 0.030 0.021 0.022 0.005 0.343 0.614 none

USGS 40 433411112561101 Chloride 56 16.3 39.0 24.0 25.0 5.88 -2.62 0.000

–

Sodium 22 9.50 20.0 13.7 13.8 2.25 -0.648 0.221 none

Sulfate 18 23.1 29.0 24.5 24.9 1.56 -0.575 0.020

–
Table 7 89

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 40 Nitrate plus nitrite as N 22 2.187 11.0 5.36 5.29 1.88 1.03 0.393 none

Ammonia 22 0.000 0.041 0.011 NA NA -0.268 0.927 none

Orthophosphate as P 22 0.000 0.041 0.020 NA NA -0.135 0.917 none

USGS 41 433409112561301 Chloride 37 16.9 32.0 19.8 21.4 3.80 -1.92 0.000 –

Sodium 24 8.70 14.0 10.7 10.9 1.43 0.013 0.972 none

Sulfate 19 22.5 30.0 24.6 24.6 1.69 -0.725 0.003 –

Nitrate plus nitrite as N 24 1.47 6.31 2.95 3.03 1.13 -0.064 0.951 none

Orthophosphate as P 24 0.018 0.120 0.029 0.031 0.020 -0.665 0.513 none

USGS 42 433404112561301 Chloride 37 15.0 31.0 20.0 21.4 4.22 -1.66 0.000 –

Sodium 24 8.05 13.1 10.4 10.3 1.46 0.082 0.846 none

Sulfate 19 22.3 27.0 23.8 24.2 1.18 -0.534 0.005 –

Nitrate plus nitrite as N 23 1.11 3.90 2.10 2.35 0.851 -0.071 0.950 none

Orthophosphate as P 23 0.010 0.038 0.022 0.024 0.006 2.04 0.010 +

Ammonia 23 0.000 0.041 0.006 NA NA -7.61 0.261 none

USGS 43 433415112561501 Chloride 36 19.9 34.0 25.2 25.2 3.38 -1.35 0.000 –

Sodium 23 11.0 20.0 15.3 15.5 2.11 -0.069 0.866 none

Sulfate 18 21.9 25.6 23.4 23.6 0.950 -0.300 0.054 none

Nitrate plus nitrite as N 23 3.88 20.6 6.10 7.11 3.40 -1.15 0.254 none

Ammonia 23 0.000 0.041 0.010 NA NA -2.73 0.169 none

Orthophosphate as P 23 0.000 0.032 0.017 NA NA 2.19 0.065 none

USGS 44 433409112562101 Chloride 46 9.76 26.0 15.6 16.0 4.19 -3.13 0.000 –

Sodium 24 7.01 9.10 8.04 8.10 0.499 -0.520 0.005 –

Sulfate 19 20.5 24.3 22.8 22.8 1.00 -0.296 0.094 none

Nitrate plus nitrite as N 24 0.715 1.20 0.859 0.935 0.154 -1.94 0.000 –

Orthophosphate as P 24 0.010 0.055 0.023 0.024 0.008 1.33 0.135 none

USGS 45 433402112561801 Chloride 44 13.9 23.0 19.0 19.0 2.43 -0.883 0.002 –

Sodium 24 8.11 12.1 9.48 9.64 1.06 0.516 0.077 none

Sulfate 19 20.8 25.4 23.5 23.4 1.15 -0.421 0.025 –

Nitrate plus nitrite as N 24 0.947 1.51 1.17 1.17 0.142 -0.457 0.174 none

Orthophosphate as P 24 0.010 0.030 0.021 0.021 0.005 1.55 0.032 +

USGS 46 433407112561501 Chloride 48 14.0 30.0 19.0 19.3 3.99 -2.06 0.000 –

Sodium 23 8.00 15.0 9.43 9.92 1.58 -0.817 0.045 –
90 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 46 Sulfate 19 21.6 27.0 23.7 23.8 1.28 -0.480 0.022

–

Nitrate plus nitrite as N 23 1.07 5.30 1.72 2.04 0.946 -3.01 0.002

–

Orthophosphate as P 23 0.019 0.036 0.026 0.026 0.005 0.750 0.150 none

Ammonia 23 0.000 0.041 0.007 NA NA -5.85 0.174 none

USGS 47 433407112560301 Chloride 44 11.4 44.0 27.5 27.7 6.80 -2.39 0.000

–

Sodium 23 7.39 22.0 14.0 14.1 3.33 -1.75 0.004

–

Sulfate 19 22.6 31.0 25.5 26.4 2.65 -1.18 0.001

–

Nitrate plus nitrite as N 23 0.817 10.4 3.47 4.31 2.05 -1.19 0.414 none

Orthophosphate as P 23 0.000 0.043 0.029 NA NA 1.77 0.032

+

USGS 48 433401112560301 Chloride 38 13.1 50.0 26.6 26.4 6.22 -1.75 0.000

–

Sodium 24 7.98 20.0 14.0 13.9 2.68 -1.03 0.059 none

Sulfate 19 22.7 29.0 25.9 25.8 1.66 -0.708 0.005

–

Nitrate plus nitrite as N 24 0.936 5.20 2.63 2.59 0.903 -1.10 0.304 none

Orthophosphate as P 24 0.000 0.038 0.025 NA NA 1.22 0.132 none

USGS 51 433350112560601 Chloride 35 62.0 194 139 129 39.0 4.28 0.000

+

Sodium 23 20.0 50.8 31.3 30.9 7.21 2.52 0.000

+

Sulfate 19 24.0 30.3 28.2 28.1 1.49 0.574 0.008

+

Nitrate plus nitrite as N 24 2.07 3.80 2.91 2.97 0.532 -2.36 0.000

–

Ammonia 24 0.000 0.092 0.015 NA NA -8.73 0.007

–

Orthophosphate as P 24 0.000 0.031 0.011 NA NA 4.97 0.000

+

USGS 52 433414112554201 Chloride 38 20.4 33.0 27.8 26.9 3.48 -1.37 0.000

–

Sodium 24 11.7 19.2 14.3 14.3 2.11 -0.686 0.074 none

Sulfate 19 23.0 28.0 26.0 25.9 1.14 -0.281 0.098 none

Nitrate plus nitrite as N 24 1.90 4.50 2.90 3.05 0.753 -0.531 0.445 none

Orthophosphate as P 24 0.000 0.031 0.021 NA NA 1.76 0.026

+

USGS 57 433344112562601 Chloride 57 20.7 200 139 125 53.8 -7.09 0.000

–

Sodium 23 12.2 78.1 42.0 42.9 23.0 -6.86 0.000

–

Sulfate 19 23.3 36.0 29.9 28.4 3.98 -1.92 0.000

–

Nitrate plus nitrite as N 23 1.73 3.70 3.00 2.87 0.713 -3.02 0.000

–

Orthophosphate as P 23 0.000 0.171 0.024 NA NA 0.720 0.653 none

USGS 59 433354112554701 Chloride 36 17.1 210 41.9 63.9 55.7 -5.97 0.001

–

Sodium 23 9.99 75.0 12.3 24.2 19.2 -5.37 0.001

–
Table 7 91

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 59 Sulfate 18 23.6 31.3 25.1 25.8 1.94 -0.730 0.010 –

Nitrate plus nitrite as N 23 1.03 3.00 1.36 1.53 0.522 -2.15 0.002 –

Ammonia 23 0.000 0.040 0.013 NA NA -5.51 0.003 –

Orthophosphate as P 23 0.000 0.035 0.021 NA NA 2.06 0.006 +

USGS 67 433344112554101 Chloride 30 46.4 171 118 116 45.2 -3.76 0.000 –

Sodium 19 24.7 54.0 39.0 38.5 10.2 -3.09 0.000 –

Sulfate 18 27.5 31.5 29.2 29.3 1.37 -0.617 0.000 –

Nitrate plus nitrite as N 20 2.53 5.57 4.33 4.29 1.02 1.78 0.011 +

Orthophosphate as P 20 0.000 0.041 0.020 NA NA 1.71 0.167 none

USGS 77 433315112560301 Chloride 37 71.7 162 130 125 23.5 -1.61 0.001 –

Sodium 32 32.0 46.0 35.3 36.4 3.77 0.295 0.283 none

Sulfate 27 27.9 33.0 31.0 30.8 1.37 -0.616 0.000 –

Nitrate plus nitrite as N 32 2.20 4.90 3.31 3.52 0.741 -2.40 0.000 –

Fluoride 27 0.164 0.279 0.203 0.210 0.023 0.996 0.001 +

Orthophosphate as P 32 0.000 0.041 0.015 NA NA 2.83 0.003 +

Chromium 27 0.000 16.4 11.3 NA NA -2.37 0.001 –

Total organic carbon 17 0.000 2.1 0.424 NA NA -2.41 0.499 none

USGS 82 433401112551001 Chloride 54 15.0 26.1 17.5 17.9 1.69 -0.557 0.004 –

Sodium 23 10.0 11.6 10.5 10.6 0.442 -0.317 0.015 –

Sulfate 19 20.0 23.0 21.4 21.5 0.697 0.051 0.687 none

Nitrate plus nitrite as N 24 0.500 0.800 0.550 0.569 0.071 -0.719 0.016 –

Ammonia 24 0.000 0.041 0.004 NA NA -11.89 0.164 none

Orthophosphate as P 24 0.000 0.076 0.017 NA NA 0.845 0.538 none

USGS 84 433356112574201 Chloride 35 5.79 15.0 9.70 9.48 2.26 -0.423 0.505 none

Sodium 32 6.86 10.0 8.55 8.63 0.980 0.193 0.559 none

Sulfate 28 23.6 38.0 31.6 31.2 4.21 0.061 0.891 none

Nitrate plus nitrite as N 28 0.626 1.10 0.866 0.875 0.141 0.908 0.095 none

Aluminum 28 2.51 9.19 4.79 4.75 1.61 -1.39 0.212 none

Molybdenum 28 1.00 2.29 1.68 1.68 0.419 -0.572 0.535 none

Barium 28 74.6 96.0 82.1 83.7 6.36 0.141 0.586 none

Uranium 28 1.00 2.00 1.65 1.65 0.221 -0.485 0.318 none

Orthophosphate as P 28 0.000 0.030 0.018 NA NA 3.68 0.000 +
92 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 84 Total organic carbon 18 0.000 2.65 0.399 NA NA -0.608 0.881 none

Chromium 34 0.000 33.0 13.9 NA NA -1.34 0.410 none

Nickel 28 0.000 4.00 0.617 NA NA -7.58 0.021

–

Lead 28 0.000 19.0 4.39 NA NA -44.4 0.000

–

Copper 28 0.000 2.36 1.31 NA NA -7.42 0.001

–

Cobalt 28 0.000 1.00 0.109 NA NA -8.77 0.015

–

Cadmium 28 0.000 1.00 0.165 NA NA -25.3 0.000

–

Arsenic 28 0.000 3.00 1.35 NA NA 1.95 0.024

+

Antimony 28 0.000 1.00 0.118 NA NA -0.856 0.689 none

Manganese 28 0.000 1.00 0.233 NA NA 0.802 0.771 none

Selenium 28 0.000 2.60 1.26 NA NA 1.44 0.068 none

Zinc 28 0.000 472 131 NA NA -39.7 0.000

–

USGS 85 433246112571201 Chloride 38 14.8 74.0 34.8 38.1 17.9 -7.32 0.000

–

Sodium 26 10.5 27.0 17.0 17.7 5.29 -4.11 0.000

–

Sulfate 20 25.3 40.2 31.4 32.9 5.25 1.89 0.000

+

Nitrate plus nitrite as N 26 1.05 3.10 1.56 1.76 0.658 -4.94 0.000

–

Orthophosphate as P 26 0.000 0.034 0.020 NA NA 1.94 0.013

+

USGS 111 433331112560501 Chloride 40 14.0 162 110 116 27.2 -0.440 0.623 none

Sodium 23 21.3 39.5 25.3 27.8 6.00 -1.83 0.000

–

Sulfate 19 26.6 37.0 28.8 29.2 2.18 -0.677 0.013

–

Nitrate plus nitrite as N 24 2.27 3.80 2.41 2.63 0.454 -1.70 0.000

–

Orthophosphate as P 24 0.000 0.023 0.010 NA NA 2.25 0.024

+

USGS 112 433314112563001 Chloride 61 21.6 200 130 127 54.2 -8.52 0.000

–

Sodium 25 15.6 78.7 47.0 44.6 21.5 -6.33 0.000

–

Sulfate 21 27.8 40.0 29.8 30.8 3.25 -0.872 0.005

–

Nitrate plus nitrite as N 25 1.35 4.30 2.68 2.58 0.923 -4.94 0.000

–

Orthophosphate as P 25 0.010 0.033 0.021 0.022 0.005 2.19 0.000

+

USGS 113 433314112561801 Chloride 59 15.7 240 190 175 58.4 -6.14 0.000

–

Sodium 23 25.4 98.7 74.9 66.2 26.1 -6.06 0.000

–

Sulfate 21 26.8 43.0 31.0 31.8 4.46 -1.66 0.000

–

Orthophosphate as P 24 0.000 0.036 0.019 NA NA 2.77 0.003

+

Nitrate plus nitrite as N 24 0.000 5.10 2.14 NA NA 0.998 0.638 none
Table 7 93

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

USGS 114 433318112555001 Chloride 59 64.0 101 81.0 81.8 8.31 0.857 0.000 +

Sodium 25 19.6 23.8 22.0 22.2 0.975 0.172 0.173 none

Sulfate 21 25.0 29.0 27.3 27.3 1.07 0.186 0.177 none

Nitrate plus nitrite as N 25 2.53 4.10 3.43 3.43 0.504 -1.94 0.000 –

Orthophosphate as P 25 0.000 0.021 0.012 NA NA -0.575 0.604 none

USGS 115 433320112554101 Chloride 59 33.0 54.3 38.0 38.8 4.69 0.856 0.000 +

Sodium 24 9.72 19.4 15.0 14.9 1.95 0.677 0.065 none

Sulfate 20 20.0 26.0 22.4 22.7 1.79 0.539 0.046 +

Nitrate plus nitrite as N 24 0.962 1.57 1.38 1.37 0.123 -0.211 0.448 none

Orthophosphate as P 24 0.000 0.021 0.010 NA NA -0.616 0.542 none

USGS 116 433331112553201 Chloride 58 12.0 131 92.9 91.4 18.7 1.93 0.005 +

Sodium 24 24.8 35.2 29.0 29.6 2.76 0.490 0.060 none

Sulfate 20 30.1 38.0 34.0 33.6 2.19 -0.907 0.000 –

Nitrate plus nitrite as N 24 2.18 3.20 2.80 2.72 0.286 -0.997 0.000 –

Orthophosphate as P 24 0.000 0.027 0.013 NA NA 1.37 0.191 none

USGS 123 433352112561401 Chloride 33 20.0 150 105 88.1 44.8 -10.1 0.000 –

Sodium 22 9.41 56.0 39.5 32.6 18.2 -9.69 0.000 –

Sulfate 18 20.7 31.0 28.0 25.9 4.20 -2.74 0.000 –

Nitrate plus nitrite as N 22 0.763 5.00 3.74 2.71 1.65 -9.33 0.000 –

Orthophosphate as P 22 0.000 0.605 0.028 NA NA 2.07 0.428 none

USGS 128 433250112565601 Chloride 11 14.4 53.3 15.2 19.7 11.5 -8.74 0.000 –

Nitrate plus nitrite as N 11 1.05 2.18 1.15 1.25 0.319 -4.48 0.000 –

Orthophosphate as P 11 0.016 0.029 0.023 0.023 0.005 5.57 0.000 +

Advanced Test Reactor Complex

MTR TEST 433520112572601 Chloride 37 9.24 16.0 10.9 11.7 1.82 -1.66 0.000 –

Sodium 37 8.85 42.4 15.0 17.8 8.72 -5.51 0.000 –

Sulfate 27 20.4 160 34.8 55.2 42.6 -10.0 0.000 –

Nitrate plus nitrite as N 24 0.938 1.40 1.06 1.09 0.124 -1.36 0.000 –

Orthophosphate as P 24 0.000 0.027 0.015 NA NA 3.45 0.000 +

Chromium 36 0.000 25.8 5.14 NA NA -1.33 0.252 none

TRA Disposal 433506112572301 Chloride 41 6.80 15.0 11.0 11.1 1.34 -0.177 0.517 none

Sodium 21 9.97 12.0 10.9 10.8 0.672 -0.410 0.021 –
94 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Advanced Test Reactor Complex—Continued

TRA Disposal Sulfate 17 27.9 45.0 32.5 34.5 5.23 -1.82 0.000

–

Nitrate plus nitrite as N 21 0.978 1.20 1.07 1.10 0.073 -0.666 0.000

–

Orthophosphate as P 21 0.027 0.084 0.048 0.049 0.011 -0.009 0.989 none

Chromium 37 7.73 23.0 10.3 11.5 3.19 -0.401 0.484 none

USGS 58 433500112572502 Chloride 35 10.2 13.3 12.0 11.9 0.777 0.140 0.451 none

Sodium 22 8.96 11.1 10.0 9.96 0.515 0.415 0.016

+

Sulfate 18 26.1 35.0 30.6 30.7 2.78 1.27 0.003

+

Chromium 34 8 22.9 12.2 12.3 3.00 0.634 0.331 none

USGS 65 433447112574501 Chloride 60 12.0 24.0 18.7 18.8 1.68 -0.200 0.326 none

Sodium 37 11.6 16.2 14.0 14.0 1.07 0.632 0.002

+

Sulfate 33 140 167 155 153 7.41 0.473 0.001

+

Nitrate plus nitrite as N 35 1.20 1.72 1.54 1.56 0.094 0.197 0.258 none

Chromium 57 77.8 210 174 160 35.1 -4.18 0.000

–

Barium 30 44.9 56.0 49.6 49.5 3.01 -0.805 0.000

–

Uranium 29 1.73 3.15 2.00 2.20 0.442 2.82 0.000

+

Orthophosphate as P 35 0.000 0.080 0.012 NA NA 4.34 0.001

+

Total organic carbon 18 0.000 1.33 0.437 NA NA -1.84 0.511 none

Nickel 30 0.000 10.0 0.976 NA NA 2.84 0.474 none

Molybdenum 30 0.000 10.0 2.59 NA NA 1.72 0.000

+

Lead 30 0.000 10.0 0.750 NA NA -31.1 0.000

–

Copper 30 0.000 10.0 0.973 NA NA -3.56 0.053 none

Cobalt 30 0.000 3.00 0.202 NA NA -7.80 0.008

–

Cadmium 30 0.000 1.00 0.030 NA NA -6.98 0.000

–

Arsenic 30 0.000 2.00 1.02 NA NA 2.26 0.000

+

Aluminum 30 0.000 10.2 4.68 NA NA -0.735 0.616 none

Antimony 29 0.000 1.00 0.165 NA NA -0.330 0.820 none

Manganese 30 0.000 3.00 0.292 NA NA -1.38 0.727 none

Selenium 30 0.000 2.60 1.79 NA NA 0.782 0.203 none

Zinc 30 0.000 420 83.2 NA NA -40.0 0.000

–

USGS 76 433425112573201 Chloride 41 9.90 15.0 12.0 12.1 1.16 0.232 0.298 none

Sodium 24 9.01 10.5 9.63 9.66 0.442 0.506 0.000

+

Sulfate 22 26.0 31.9 27.9 28.8 2.21 0.886 0.000

+

Nitrate plus nitrite as N 25 1.00 2.22 1.11 1.17 0.230 -0.085 0.845 none
Table 7 95

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Advanced Test Reactor Complex—Continued

USGS 76 Orthophosphate as P 25 0.000 0.080 0.020 NA NA 0.954 0.434 none

Chromium 37 0.000 18.7 11.3 NA NA -0.324 0.472 none

USGS 79 433505112581901 Chloride 38 10.7 17.0 12.4 12.6 1.35 -1.15 0.000 –

Sodium 24 7.70 12.5 8.64 8.74 0.876 0.075 0.773 none

Sulfate 19 22.0 29.8 23.5 24.5 2.43 -0.683 0.068 none

Chromium 36 0.000 14.0 6.12 NA NA -0.578 0.284 none

Central Facilities Area

CFA 1 433204112562001 Chloride 61 17.0 120 99.5 95.6 17.0 0.572 0.324 none

Sodium 61 14.0 35.3 26.0 25.3 5.21 0.388 0.419 none

Sulfate 41 26.1 37.0 30.9 30.7 2.31 -0.603 0.007 –

Nitrate plus nitrite as N 23 2.57 4.50 3.30 3.37 0.575 -1.81 0.000 –

Orthophosphate as P 23 0.000 0.030 0.016 NA NA 0.159 0.883 none

Chromium 23 0.000 22.0 14.6 NA NA -0.726 0.651 none

CFA 2 433144112563501 Chloride 55 70.0 145 104 107 19.1 2.50 0.000 +

Sodium 55 16.0 39.4 24.1 24.3 6.09 3.55 0.000 +

Sulfate 35 33.0 52.7 46.7 45.4 4.67 1.37 0.000 +

Nitrate plus nitrite as N 19 2.70 4.10 3.71 3.50 0.458 1.45 0.000 +

Orthophosphate as P 19 0.000 0.026 0.014 NA NA 1.84 0.115 none

Chromium 20 0.000 21.0 11.6 NA NA 0.805 0.571 none

CFA LF 2-10 433216112563301 Chloride 29 21.5 35.8 30.9 29.8 4.35 -0.410 0.433 none

Sodium 28 10.0 13.8 12.0 12.1 0.843 0.554 0.026 +

Nitrate plus nitrite as N 30 1.2 2.0 1.5 1.5 0.236 -1.33 0.004 –

Chromium 27 7.9 18.3 12.0 11.9 2.25 -1.59 0.007 –

Orthophosphate as P 30 0.014 0.034 0.020 0.020 0.005 1.34 0.074 none

Ammonia 30 0.000 0.041 0.010 NA NA -7.76 0.089 none

Total organic carbon 18 0.000 2.0 0.474 NA NA -3.24 0.368 none

CFA LF 3-9 433216112571001 Chloride 13 94.0 157 114 116 16.8 1.57 0.032 +

Nitrate plus nitrite as N 13 2.9 4.1 3.4 3.5 0.377 -2.16 0.001 –

Ammonia 13 0.000 0.040 0.017 NA NA 2.16 0.518 none

Orthophosphate as P 13 0.000 0.040 0.015 NA NA -5.17 0.082 none

USGS 127 433058112572201 Chloride 18 13.4 16.4 14.9 14.9 0.750 0.555 0.076 none

Sodium 18 7.6 8.9 8.3 8.3 0.343 0.630 0.015 +
96 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

Central Facilities Area—Continued

USGS127 Nitrate plus nitrite as N 18 0.527 0.589 0.556 0.559 0.019 0.265 0.201 none

Chromium 18 8.9 12.8 10.6 10.5 1.13 -1.37 0.039

–

Orthophosphate as P 18 0.000 0.030 0.015 NA NA 4.63 0.001

+

Radioactive Waste Management Complex

RWMC M3S 433008113021801 Chloride 20 11.8 14.9 13.2 13.2 1.06 1.19 0.000

+

Nitrate plus nitrite as N 21 0.690 0.920 0.814 0.813 0.042 0.075 0.683 none

Orthophosphate as P 21 0.009 0.040 0.019 0.019 0.007 -0.581 0.637 none

RWMC M7S 433023113014801 Chloride 20 10.9 14.4 12.1 12.3 1.14 1.38 0.000

+

Nitrate plus nitrite as N 21 0.550 0.778 0.698 0.694 0.058 1.11 0.000

+

Orthophosphate as P 21 0.012 0.060 0.020 0.022 0.010 -1.83 0.137 none

RWMC M11S 433058113010401 Chloride 15 13.2 33.1 17.6 19.7 5.59 -1.03 0.504 none

Sodium 15 10.9 13.1 11.4 11.7 0.737 -0.088 0.816 none

Nitrate plus nitrite as N 15 0.427 0.605 0.513 0.510 0.056 0.715 0.271 none

Orthophosphate as P 15 0.000 0.025 0.014 NA NA 6.32 0.000

+

Chromium 15 0.000 13.0 9.17 NA NA 0.906 0.519 none

Total organic carbon 12 0.000 0.745 0.361 NA NA -10.3 0.001

–

RWMC M12S 433118112593401 Chloride 14 15.0 17.4 16.0 16.2 0.769 1.04 0.001

+

Sodium 14 8.00 10.5 8.25 8.46 0.642 0.013 0.978 none

Nitrate plus nitrite as N 14 0.838 0.998 0.930 0.922 0.044 0.997 0.001

+

Chromium 14 12.7 20.6 13.8 15.1 2.39 -2.35 0.001

–

Orthophosphate as P 14 0.014 0.033 0.021 0.021 0.005 4.00 0.002

+

Total organic carbon 11 0.000 3.63 0.560 NA NA -22.5 0.016

–

RWMC M13S 433037113002701 Chloride 15 5.60 6.52 6.02 6.02 0.242 0.143 0.560 none

Sodium 15 9.94 12.0 11.3 11.2 0.477 0.362 0.176 none

Nitrate plus nitrite as N 15 0.328 0.413 0.360 0.363 0.019 0.465 0.151 none

Chromium 15 7.78 11.3 8.79 9.20 1.05 -1.32 0.054 none

Orthophosphate as P 15 0.009 0.079 0.016 0.020 0.017 1.55 0.634 none

Total organic carbon 12 0.000 1.67 0.417 NA NA -14.1 0.027

–

RWMC M14S 433052113025001 Chloride 15 14.1 16.7 15.4 15.3 0.733 0.234 0.425 none

Sodium 15 8.32 9.68 9.01 8.96 0.333 -0.088 0.701 none

Nitrate plus nitrite as N 14 0.831 0.964 0.893 0.901 0.041 0.336 0.251 none

Chromium 15 11.6 19.1 13.6 14.5 2.01 -1.91 0.004

–
Table 7 97

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Aquifer wells—Continued

Radioactive Waste Management Complex—Continued

RWMC M14S Orthophosphate as P 14 0.010 0.025 0.018 0.017 0.004 3.95 0.001 +

Total organic carbon 12 0.000 1.77 0.403 NA NA -18.8 0.022 –

RWMC Production 433002113021701 Chloride 63 11.0 23.4 16.6 16.8 2.65 2.18 0.000 +

Sodium 24 7.20 9.56 8.49 8.47 0.504 0.520 0.002 +

Sulfate 20 24.3 29.0 27.0 27.0 1.37 0.311 0.054 none

Nitrate plus nitrite as N 25 0.140 0.962 0.840 0.808 0.179 -0.472 0.653 none

Orthophosphate as P 25 0.000 0.074 0.018 NA NA 6.42 0.000 +

USGS 87 433013113024201 Chloride 63 11.0 37.7 14.0 15.7 5.19 2.89 0.000 +

Sodium 35 8.54 18.5 10.1 11.4 2.53 1.94 0.000 +

Sulfate 21 22.9 29.0 25.4 25.2 1.40 -0.107 0.546 none

Nitrate plus nitrite as N 35 0.438 1.60 0.743 0.741 0.187 -1.41 0.007 –

Chromium 30 1.63 18.6 13.5 11.4 4.24 -6.55 0.000 –

Orthophosphate as P 35 0.000 0.198 0.011 NA NA 2.60 0.123 none

Total organic carbon 18 0.000 3.10 0.501 NA NA -7.42 0.150 none

USGS 88 432940113030201 Chloride 61 29.0 111 84.2 84.5 9.65 0.223 0.524 none

Sodium 24 40.7 48.0 44.0 44.2 1.69 -0.215 0.050 –

Sulfate 18 27.4 64.0 58.2 55.0 9.36 -2.11 0.000 –

Nitrate plus nitrite as N 24 0.184 1.80 1.35 1.25 0.418 -4.89 0.000 –

Ammonia 23 0.000 0.398 0.033 NA NA 5.89 0.075 none

Orthophosphate as P 24 0.000 0.029 0.006 NA NA 0.759 0.712 none

USGS 89 433005113032801 Chloride 62 13.0 46.3 39.0 38.6 4.04 0.462 0.157 none

Sodium 24 13.0 21.5 19.2 19.3 1.56 0.353 0.160 none

Nitrate plus nitrite as N 25 1.63 2.10 1.76 1.78 0.119 -0.581 0.001 –

Orthophosphate as P 25 0.000 0.060 0.010 NA NA 1.65 0.142 none

Sulfate 20 0.000 38.0 35.1 NA NA -0.118 0.346 none

USGS 120 432919113031501 Chloride 63 14.8 30.0 21.8 21.9 3.64 -2.25 0.000 –

Sodium 34 13.8 47.6 26.2 28.4 9.52 -2.74 0.000 –

Sulfate 19 28.8 53.4 37.0 38.4 7.73 -1.75 0.001 –

Nitrate plus nitrite as N 34 0.563 1.10 0.841 0.809 0.110 -0.260 0.488 none

Orthophosphate as P 34 0.000 0.030 0.015 NA NA 1.49 0.064 none

Total organic carbon 17 0.000 3.22 1.14 NA NA -4.75 0.060 none

Chromium 30 0.000 14.0 8.82 NA NA -0.013 0.984 none
98 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Aquifer wells—Continued

South of facilities

USGS 104 432856112560801 Chloride 59 10.0 17.0 12.0 12.5 1.09 0.549 0.002

+

Sodium 23 8.10 9.30 8.55 8.61 0.390 0.337 0.013

+

Nitrate plus nitrite as N 23 0.660 0.869 0.776 0.770 0.069 1.22 0.000

+

Orthophosphate as P 23 0.000 0.041 0.013 NA NA 2.41 0.059 none

USGS 105 432703113001801 Chloride 33 11.7 22.0 13.3 13.9 2.03 -1.66 0.000

–

Sodium 27 11.6 14.0 13.0 13.1 0.660 -0.486 0.016

–

Nitrate plus nitrite as N 22 0.580 0.727 0.644 0.649 0.044 0.892 0.013

+

Orthophosphate as P 22 0.000 0.020 0.011 NA NA 2.09 0.218 none

Total organic carbon 13 0.000 2.20 0.552 NA NA -6.93 0.088 none

Chromium 22 0.000 14.0 8.04 NA NA 1.16 0.248 none

USGS 106 432959112593101 Chloride 42 12.0 18.0 14.9 14.7 1.07 0.260 0.126 none

Sodium 24 6.73 8.43 7.77 7.77 0.426 0.368 0.022

+

USGS 108 432659112582601 Chloride 34 13.0 20.0 14.3 14.5 1.14 -0.062 0.789 none

Sodium 28 10.0 12.0 11.0 11.0 0.394 0.119 0.380 none

Nitrate plus nitrite as N 24 0.600 1.10 0.708 0.717 0.090 0.173 0.719 none

Orthophosphate as P 24 0.000 0.018 0.011 NA NA 1.92 0.035

+

Total organic carbon 14 0.000 3.52 0.431 NA NA 10.5 0.178 none

Chromium 24 0.000 14.0 7.74 NA NA -0.053 0.955 none

USGS 124 432307112583101 Chloride 30 12.9 16.0 14.8 14.7 0.752 0.534 0.003

+

Sodium 21 8.66 10.3 9.35 9.45 0.421 0.154 0.357 none

Nitrate plus nitrite as N 21 0.660 0.869 0.794 0.780 0.053 0.686 0.010

+

Orthophosphate as P 21 0.000 0.024 0.012 NA NA 4.71 0.000

+

Perched groundwater wells

Idaho Nuclear Technology and Engineering Center

PW 1 433349112560701 Chloride 44 134 386 259 245 58.7 -5.57 0.000

–

Sodium 11 105 210 160 164 30.2 -2.73 0.087 none

PW 2 433344112555601 Chloride 34 148 311 259 247 39.7 -2.73 0.000

–

Sodium 14 106 190 160 152 25.7 -3.36 0.000

–

Sulfate 10 23.0 41.0 26.8 29.1 5.93 0.861 0.548 none

PW 3 433351112555701 Chloride 31 150 337 270 262 43.5 -2.25 0.003

–

Sodium 10 127 184 170 166 16.2 -1.22 0.178 none
Table 7 99

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Perched groundwater wells—Continued

Idaho Nuclear Technology and Engineering Center—Continued

PW 4 433348112554901 Chloride 51 79.0 325 270 254 59.2 -3.56 0.000 –

Sodium 18 83.0 190 151 141 38.2 -4.52 0.000 –

Sulfate 13 24.9 50.8 28.6 32.4 7.80 2.38 0.016 +

PW 5 433348112555701 Chloride 30 149 350 260 259 49.3 -1.48 0.122 none

Sodium 12 127 190 161 164 18.6 -1.58 0.055 none

PW 6 433353112562201 Chloride 29 13 1,500 170 199 256 -2.87 0.499 none

USGS 50 433419112560201 Chloride 38 30.0 86.0 67.0 64.9 11.8 -2.38 0.000 –

Sodium 17 20.0 69.0 62.0 60.0 11.0 -1.90 0.083 none

Sulfate 13 25.0 44.0 39.3 38.1 5.73 0.599 0.478 none

Nitrate plus nitrite as N 18 4 62.0 34.5 35.9 17.3 -6.57 0.024 –

Orthophosphate as P 18 0.012 0.102 0.040 0.042 0.019 -1.18 0.517 none

Ammonia 18 0.000 0.041 0.014 NA NA -11.1 0.028 –

Advanced Test Reactor Complex

CWP 1 433459112572601 Chloride 26 8.70 31.6 14.4 19.2 8.30 0.338 0.783 none

Sulfate 19 25.8 419 320 236 156 -7.06 0.045 –

Chromium 24 0.000 14.0 2.61 NA NA -1.09 0.515 none

CWP 2 433458112572401 Chloride 11 5.70 24.0 15.0 15.5 5.34 -3.80 0.180 none

CWP 3 433455112572501 Chloride 25 10.0 29.1 18.9 18.4 6.55 0.853 0.400 none

Sulfate 18 28.0 365 222 210 115 -3.18 0.315 none

Chromium 23 0.000 14.0 1.83 NA NA -8.35 0.000 –

CWP 4 433454112572601 Chloride 14 8.00 20.0 12.0 13.0 3.49 -2.37 0.028 –

CWP 8 433500112573001 Chloride 23 4.66 91.0 12.5 16.1 16.9 -3.86 0.003 –

Sulfate 17 26.6 240 68.9 85.9 58.4 -6.42 0.001 –

Chromium 21 0.000 14.0 0.841 NA NA -3.32 0.078 none

PW 8 433456112572001 Chloride 60 5.90 25.7 20.0 19.2 3.89 0.934 0.089 none

Sodium 23 12.0 19.4 16.1 15.8 2.10 0.324 0.420 none

Sulfate 32 66.0 298 240 224 58.3 -1.98 0.049 –

Chromium 56 0.000 40.0 9.87 NA NA -3.94 0.000 –

PW 9 433500112575401 Chloride 59 10.4 47.3 27.0 28.4 5.43 1.72 0.000 +

Sodium 22 19.0 23.0 20.9 20.9 1.26 -0.429 0.015 –
100 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

PW9 Sulfate 30 70.9 120 104 98.7 13.9 -1.22 0.003

–

Chromium 55 5.95 240 79.9 93.5 66.2 -10.1 0.000

–

TRA A 13 433502112572802 Chloride 19 3.30 53.1 27.3 28.9 11.6 6.35 0.041

+

TRA A 77 433507112573801 Chloride 22 0.300 9.82 1.15 2.39 3.06 19.9 0.018

+

USGS 53 433503112573401 Chloride 14 5.70 35.0 17.0 18.2 8.14 0.058 0.974 none

Sodium 9 9.00 30.8 15.0 17.4 7.53 1.98 0.154 none

Chromium 12 0.000 590 43.0 NA NA -13.1 0.103 none

USGS 54 433503112572801 Chloride 55 9.40 29.0 18.5 18.6 4.92 -0.780 0.208 none

Sodium 23 12.0 20.9 15.5 15.6 2.64 -0.574 0.256 none

Sulfate 31 49.9 330 220 203 89.8 -5.84 0.000

–

Chromium 51 0.000 66.0 9.08 NA NA -5.24 0.000

–

USGS 55 433508112573001 Chloride 31 12.0 32.0 20.0 21.3 5.81 -2.81 0.000

–

Sodium 20 6.40 32.0 18.6 19.8 6.02 -1.55 0.157 none

Sulfate 17 35.0 210 113 113 45.8 2.14 0.253 none

Chromium 29 15.4 130 47.0 52.0 29.3 -4.13 0.012

–

USGS 56 433509112573501 Chloride 17 7.20 34.0 16.3 17.1 7.73 0.874 0.537 none

Sodium 10 12.0 250 36.1 55.2 70.2 -0.542 0.865 none

Chromium 15 27.9 200 86.4 97.9 48.6 -2.82 0.101 none

USGS 60 433456112571901 Chloride 44 10.2 110 18.6 20.3 14.4 -1.26 0.126 none

Sodium 23 7.90 18.8 13.6 14.1 2.85 0.118 0.857 none

Sulfate 19 53.9 283 158 189 79.6 -3.55 0.031

–

Chromium 40 0.000 24.0 7.33 NA NA -2.54 0.017

–

USGS 61 433453112571601 Chloride 38 12.8 24.0 18.0 17.5 2.40 -0.308 0.387 none

Sodium 24 11.3 17.0 13.9 13.6 1.28 -0.612 0.027

–

Sulfate 19 77.0 190 162 150 34.9 -1.21 0.240 none

Chromium 36 0.000 35.0 15.7 NA NA -5.31 0.000

–

USGS 62 433446112570701 Chloride 38 12.0 25.3 20.3 19.7 3.25 0.219 0.639 none

Sodium 24 12.0 18.0 16.0 16.0 1.54 0.264 0.374 none

Sulfate 19 81.1 270 223 212 50.7 -1.51 0.188 none

Chromium 36 0.000 69.0 12.0 NA NA -5.71 0.000

–
Table 7 101

Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National 

Laboratory, Idaho, 1989–2012.—Continued

[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

USGS 63 433455112574001 Chloride 38 11.0 25.0 19.9 19.4 3.20 -0.208 0.642 none

Sodium 24 12.0 18.7 16.0 15.7 1.52 0.155 0.589 none

Sulfate 19 90.6 272 214 198 52.7 -2.92 0.002 –

Chromium 36 0.000 180 19.8 NA NA -8.94 0.000 –

USGS 66 433436112564801 Chloride 27 14.0 23.0 19.0 19.1 2.54 -0.258 0.476 none

Sodium 23 14.0 17.6 15.3 15.5 0.901 0.020 0.910 none

Sulfate 19 110 233 190 188 32.1 0.077 0.914 none

Chromium 25 0.000 100 5.23 NA NA -7.61 0.069 none

USGS 68 433516112573901 Chloride 45 9.00 75.0 35.0 34.1 11.6 -1.51 0.047 –

Sodium 24 146 1,300 642 675 340 -7.95 0.000 –

Sulfate 20 467 4,300 1,511 1,937 1,119 -8.53 0.000 –

Chromium 35 0.000 70.0 13.3 NA NA 11.9 0.000 +

USGS 69 433450112573001 Chloride 28 12.4 28.0 17.1 17.7 3.24 -1.27 0.001 –

Sodium 24 8.72 36.0 11.0 11.8 5.23 -1.31 0.063 none

Sulfate 19 46.6 164 112 109 33.3 -3.75 0.000 –

Chromium 25 0.000 14.0 1.95 NA NA -2.97 0.082 none

USGS 70 433504112571001 Chloride 38 11.7 31.0 18.1 18.8 3.41 -1.06 0.010 –

Sodium 24 11.7 21.0 15.8 15.9 1.94 -0.537 0.123 none

Sulfate 19 52.1 239 165 161 46.3 -2.45 0.053 none

Chromium 36 0.000 55.0 21.3 NA NA -4.73 0.000 –

USGS 71 433439112571501 Chloride 33 16.0 23.0 18.6 18.7 1.57 -0.068 0.746 none

Sodium 22 8.30 14.4 12.4 12.2 1.42 1.19 0.000 +

Sulfate 18 140 181 169 165 12.7 0.561 0.065 none

Chromium 31 0.000 87.0 30.8 NA NA -9.18 0.000 –

USGS 72 433519112574601 Chloride 25 10.9 83.0 16.3 19.8 14.0 -0.304 0.778 none

Sodium 18 18.5 34.2 27.4 26.5 5.17 0.088 0.905 none

Sulfate 16 25.1 38.0 27.5 29.2 4.14 -1.64 0.002 –

Chromium 14 0.000 14.0 1.33 NA NA -5.71 0.735 none

USGS 73 433502112575401 Chloride 37 19.0 214 38.1 47.9 34.2 2.26 0.044 +

Sodium 23 12.5 21.0 17.8 17.1 2.63 0.554 0.213 none

Sulfate 18 43.0 83.5 56.4 59.0 9.94 0.521 0.391 none

Chromium 35 0.000 100 42.2 NA NA -6.86 0.000 –
102 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 7. Summary statistics and trend test results for selected constituents in water from aquifer and perched groundwater wells at and near the Idaho National Laboratory, Idaho, 1989–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/ nwis). Constituent: Aluminum, antimony, arsenic, barium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, selenium, uranium, and zinc in micrograms per liter. N, nitrogen; P, phosphorus. Slope: In percent change per year. 

p value: Is for linear trend over time. The minimum values listed as 0.000 are reported as less than a reporting level in the National 

Water Information System database. Trend: +, increasing; –, decreasing. NA, value could not be calculated because some values were less than a reporting level]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

Perched groundwater wells—Continued

Advanced Test Reactor Complex—Continued

USGS 78 433413112573501 Chloride 18 3.11 5.53 4.56 4.44 0.697 1.05 0.122 none

Sodium 18 5.09 7.26 6.51 6.45 0.524 -0.693 0.057 none

Sulfate 18 12.4 21.1 19.7 19.2 1.90 0.341 0.492 none

Chromium 17 0.000 14.0 1.58 NA NA -11.5 0.000

–

Radioactive waste management complex

USGS 92 433000113025301 Chloride 19 69.0 150 87.3 91.4 18.4 0.651 0.273 none
Table 8 103

Table 8. Summary statistics and trend test results for volatile organic compounds in water from aquifer wells at and near the Idaho National Laboratory, Idaho, 1987–2012.[See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituents: All constituents in micrograms per liter. Slope: The linear trend over time in percent change per year. p value: Is for linear trend over time. Trend: +, increasing; –, decreasing; 

minimum values reported as 0.000 were reported as less than their reporting levels in the National Water Information System database. NA, value could not be calculated because some values less than reporting levels]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope p value Trend

1987–2012

Idaho Nuclear Technology and Engineering Center

USGS 34 433334112565501 Dichlorodifluoromethane 29 0.000 0.200 0.150 NA NA -0.670 0.623 none

1,1,1-Trichloroethane 29 0.000 0.400 0.151 NA NA -7.35 0.000 –

USGS 38 433322112564301 Dichlorodifluoromethane 29 0.000 0.200 0.150 NA NA -1.12 0.388 none

1,1,1-Trichloroethane 29 0.000 0.600 0.169 NA NA -8.35 0.000 –

USGS 77 433315112560301 Dichlorodifluoromethane 27 0.000 0.200 0.130 NA NA -2.46 0.011 –

1,1,1-Trichloroethane 27 0.000 0.600 0.234 NA NA -9.18 0.000 –

1,1-Dichloroethene 27 0.000 0.200 0.143 NA NA -4.35 0.000 –

USGS 84 433356112574201 Dichlorodifluoromethane 28 0.000 0.200 0.125 NA NA -6.23 0.001 –

Advanced test reactor complex

USGS 65 433447112574501 Dichlorodifluoromethane 31 0.000 0.675 0.159 NA NA -1.16 0.670 none

1,1,1-Trichloroethane 31 0.000 1.1 0.256 NA NA -9.43 0.000 –

Radioactive waste management complex

RWMC Production 433002113021701 Trichloroethene 289 0.400 4.88 2.39 2.37 1.11 7.45 0.000 +

Carbon tetrachloride 289 1.00 11.6 5.05 5.07 2.42 7.26 0.000 +

Trichloromethane 289 0.000 4.00 0.783 NA NA 11.2 0.000 +

Tetrachloroethene 289 0.000 0.467 0.232 NA NA 4.17 0.000 +

1,1,1-Trichloroethane 289 0.000 0.764 0.489 NA NA 1.21 0.000 +

Tribromomethane 289 0.000 2.76 0.008 NA NA 19.9 0.000 +

Orthophosphate as P 25 0.000 0.074 0.018 NA NA 6.42 0.000 +

USGS 87 433013113024201 Trichloroethene 71 0.000 1.70 0.392 NA NA 6.99 0.000 +

Trichloromethane 71 0.000 0.353 0.120 NA NA 5.36 0.000 +

Dichlorodifluoromethane 71 0.000 1.87 0.094 NA NA 13.0 0.000 +

Tetrachloroethene 71 0.000 0.204 0.107 NA NA 0.798 0.490 none

Carbon tetrachloride 71 0.000 5.07 1.469 NA NA 9.57 0.000 +

1,1,1-Trichloroethane 71 0.000 0.243 0.193 NA NA 0.049 0.830 none

Total organic carbon 18 0.000 3.10 0.501 NA NA -7.42 0.150 none
104 Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012 Table 8. Summary statistics and trend test results for volatile organic compounds in water from aquifer wells at and near the Idaho National Laboratory, Idaho, 1987–2012.—Continued [See figures 2 and 3 for well locations. Local name: Local well identifier used in this study. Site identifier: Unique numerical identifier used to access well data (http://waterdata.usgs.gov/nwis). Constituents: All constituents in micrograms per liter. Slope: The linear trend over time in percent change per year. 

p value: Is for linear trend over time. Trend: +, increasing; –, decreasing; 

minimum values reported as 0.000 were reported as less than their reporting levels in the National Water Information System database. NA, value could not be calculated because some values less than reporting levels]

Local name

Site 

identifier Constituent Sample size Minimum Maximum Median Mean Standard deviation Slope

p value Trend

1987–2012—Continued

Radioactive waste management complex—Continued

USGS 88 432940113030201 Trichloroethene 72 0.366 2.30 0.707 0.758 0.286 -3.82 0.000

–

Trichloromethane 72 0.000 1.00 0.457 NA NA -0.405 0.303 none

Carbon tetrachloride 72 0.500 6.10 1.60 1.76 0.879 -5.07 0.000

–

1,1,1-Trichloroethane 72 0.000 0.900 0.211 NA NA -8.32 0.000

–

Ammonia 23 0.000 0.398 0.033 NA NA 5.89 0.075 none

Orthophosphate as P 24 0.000 0.029 0.006 NA NA 0.759 0.712 none

USGS 120 432919113031501 Carbon tetrachloride 69 0.400 7.02 1.10 1.88 1.63 4.92 0.001

+

Trichloroethene 69 0.000 2.31 0.316 NA NA 3.76 0.090 none

Trichloromethane 69 0.000 1.25 0.125 NA NA 8.88 0.004

+

Tetrachloroethene 69 0.000 0.268 0.130 NA NA -1.84 0.028

–

1,1,1-Trichloroethane 69 0.000 0.646 0.185 NA NA -0.265 0.855 none

2005–2012

RWMC production 433002113021701 Carbon tetrachloride 95 4.75 11.6 7.53 7.67 1.52 1.67 0.054 none
Appendixes 105

Appendixes

Appendixes A–E are PDFs and can be downloaded from http://pubs.usgs.gov/sir/2015/5003/.

Appendix A. Package ‘Trends’ and Processing Instructions for the 2014 Trend Analysis

Appendix B. Plots of Trend Analyses for pH, Specific Conductance, and Water Temperature from 

Selected Sites, 1989–201215

Appendix C. Plots of Trend Analyses for Selected Radiochemical Constituents from Selected Sites,

1981–2012

Appendix D. Plots of Trend Analyses for Selected Constituents from Selected Sites, 1989–2012

Appendix E. Plots of Trend Analyses for Volatile Organic Compounds from Selected Sites, 

1987–2012

Publishing support provided by the U.S. Geological Survey 

Science Publishing Network, Tacoma Publishing Service Center

For more information concerning the research in this report, contact the 

Director, Idaho Water Science Center

U.S. Geological Survey 

230 Collins Road

Boise, Idaho 83702

http://id.water.usgs.gov
— Davis and others Water-Quality Characteristics and Trends for Selected Sites, Idaho National Laboratory, Idaho, 1981–2012—Scientific Investigations Report 2015–5003

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155003