Prepared in cooperation with the West Virginia Department of Environmental Protection, 

Division of Water and Waste Management

Groundwater Quality in West Virginia, 1993–2008

Scientific Investigations Report 2012–5186

U.S. Department of the Interior

U.S. Geological Survey
Cover. The geology of West Virginia and locations of groundwater-quality sampling sites, wells, and springs, in the West Virginia 

ambient monitoring network, 1993–2008. See figure 1 for an explanation of the geology.
Groundwater Quality in West Virginia, 

1993–2008

By Douglas B. Chambers, Mark D. Kozar, Jeremy S. White, and Katherine S. Paybins

Prepared in cooperation with 

the West Virginia Department of Environmental Protection, 

Division of Water and Waste Management

Scientific Investigations Report 2012–5186

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Chambers, D.B., Kozar, M.D., White, J.S., and Paybins, K.S., 2012, Groundwater quality in West Virginia, 1993–2008: 

U.S. Geological Survey Scientific Investigations Report 2012–5186, 47 p.
iii

Contents

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

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

Previous Investigations........................................................................................................................2

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

Study Area, Design, and Methods ..............................................................................................................3

Well Selection .......................................................................................................................................4

Collection of Site Environmental Setting Information.....................................................................4

Wells Representing Unconsolidated Alluvial Aquifers...................................................................5

Wells Representing Consolidated Bedrock Aquifers .....................................................................5

Distribution of Wells among Environmental Settings .....................................................................7

Well Sampling........................................................................................................................................7

Statistical Methods...............................................................................................................................8

Quality Assurance..........................................................................................................................................8

Blank Samples.......................................................................................................................................8

Replicate Samples..............................................................................................................................10

Groundwater Quality In West Virginia......................................................................................................11

Water-Quality Characteristics .........................................................................................................11

Specific Conductance...............................................................................................................11

pH..................................................................................................................................................11

Dissolved Oxygen and Temperature.......................................................................................14

Major Ions............................................................................................................................................14

Calcium........................................................................................................................................14

Magnesium .................................................................................................................................15

Potassium....................................................................................................................................15

Sodium ........................................................................................................................................15

Bicarbonate from Field Alkalinity............................................................................................15

Chloride........................................................................................................................................18

Sulfate..........................................................................................................................................18

Water Types................................................................................................................................18

Nutrients...............................................................................................................................................19

Nitrogen.......................................................................................................................................23

Phosphorus.................................................................................................................................24

Fecal-Indicator Bacteria ...................................................................................................................24

Trace Elements....................................................................................................................................24

Arsenic.........................................................................................................................................24

Aluminum.....................................................................................................................................27

Iron ...............................................................................................................................................30

Manganese.................................................................................................................................30

Lead..............................................................................................................................................32

Zinc...............................................................................................................................................34

Barium..........................................................................................................................................34

Radon-222.............................................................................................................................................35
iv

Organic Compounds...........................................................................................................................38

Volatile Organic Compounds....................................................................................................38

Semi-Volatile Compounds ........................................................................................................39

Pesticides....................................................................................................................................39

Relations Among Water-Quality Characteristics and Environmental Settings .................................42

Implications for Further Studies of West Virginia Groundwater Resources .....................................43

Summary and Conclusions.........................................................................................................................44

References Cited..........................................................................................................................................45

Figures

1. Map showing the geology of West Virginia and locations of groundwater-quality 

sampling sites, wells, and springs in the West Virginia ambient monitoring network, 

1993–2008 .......................................................................................................................................3

2. Boxplots showing distribution of specific conductance values in groundwater 

samples from the West Virginia ambient monitoring network, grouped by geologic 

age of the aquifers, 1993–2008 .................................................................................................12

3. Boxplots showing distribution of pH in groundwater samples from the West Virginia 

ambient monitoring network, grouped by geologic age of the aquifers, 1993–2008 .......12

4. Map showing distribution of pH values for all groundwater samples from 

the West Virginia ambient monitoring network, 1993–2008.................................................13

5. Boxplots showing distribution of calcium concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age 

of the aquifers, 1993–2008 .........................................................................................................14

6. Boxplots showing distribution of magnesium concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993–2008 ....................................................................................................................16

7. Boxplots showing distribution of potassium concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993–2008 ....................................................................................................................16

8. Boxplots showing distribution of sodium concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993–2008 ....................................................................................................................17

9. Boxplots showing distribution of bicarbonate in groundwater samples from the 

West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993–2008 ....................................................................................................................17

10. Boxplots showing distribution of chloride concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of 

the aquifers, 1993–2008..............................................................................................................18

11. Boxplots showing distribution of sulfate concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of 

the aquifers, 1993–2008..............................................................................................................19
v

12. Piper trilinear plots of indicating major ion composition of groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993-2008: A, Quaternary aquifers; B, Cambrian, Ordovician, and Silurian 

aquifers; C, Devonian aquifers; D, Mississippian aquifers; E, Pennsylvanian 

aquifers; and F, Permian aquifers ............................................................................................20

13. Boxplots showing distribution of nitrate and nitrite concentrations in groundwater 

samples from the West Virginia ambient monitoring network, grouped by geologic 

age of the aquifers, 1993–2008 .................................................................................................23

14. Maps showing distribution of groundwater samples from the West Virginia ambient 

monitoring network with at least one colony-forming unit of fecal indicator bacteria 

per 100 milliliters of sample, 1993–2008: A, Fecal coliform and B, Escherichia coli........25

15. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for total arsenic, 1993–2008..................................................27

16. Boxplots showing distribution of aluminum concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age 

of the aquifers, 1993–2008 .........................................................................................................28

17. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for total aluminum, 1993–2008..............................................29

18. Boxplots showing distribution of iron concentrations in groundwater samples from 

the West Virginia ambient monitoring network, grouped by geologic age of 

the aquifers, 1993–2008..............................................................................................................30

19. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for total iron, 1993–2008 ........................................................31

20. Boxplots showing distribution of manganese concentrations in groundwater 

samples from the West Virginia ambient monitoring network, grouped by geologic 

age, 1993–2008 ............................................................................................................................32

21. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for total manganese, 1993–2008 ..........................................33

22. Boxplots showing distribution of zinc concentrations in groundwater samples from 

the West Virginia ambient monitoring network, grouped by geologic age of the 

aquifers, 1993–2008 ....................................................................................................................34

23. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for total barium, 1993–2008...................................................35

24. Boxplots showing distribution of barium concentrations in groundwater samples 

from the West Virginia ambient monitoring network, grouped by geologic age of 

the aquifers, 1993–2008..............................................................................................................36

25. Boxplots showing distribution of radon-222 in groundwater samples from the West 

Virginia ambient monitoring network, grouped by geologic age, 1993–2008 ...................36

26. Map showing distribution of groundwater samples from the West Virginia ambient 

monitoring network analyzed for radon-222, 1993–2008 ......................................................37

27. Boxplots showing distribution of the number of volatile organic compounds detected 

per groundwater sample from the West Virginia ambient monitoring network, 

grouped by dominant rock type, 1993–2008 ...........................................................................39

28. Map showing distribution of samples from the West Virginia ambient monitoring 

network analyzed for pesticides and the number of pesticides detected per 

groundwater sample, 1993–2008..............................................................................................42

29. Boxplots showing distribution of the number of pesticides detected per groundwater 

sample from the West Virginia ambient monitoring network, grouped by dominant 

rock type, 1993–2008 ..................................................................................................................43
vi

Tables

1. Aquifer settings represented in the design of the ambient groundwater waterquality network..............................................................................................................................6

2. The distribution of samples by geologic age of aquifer.........................................................8

3. Water-quality characteristics, major ions, metals, trace elements, nutrients, 

radon-222, and fecal indicator bacteria analyzed for in groundwater samples from 

the West Virginia ambient monitoring network, 1993–2008...................................................9

4. Statistical summary of major ions for groundwater samples from West Virginia 

ambient monitoring network, 1993–2008.................................................................................15

5. Statistical summary of metals and trace elements for groundwater samples from 

West Virginia ambient monitoring network, 1993–2008........................................................26

6. Volatile organic compounds analyzed for in groundwater samples from West 

Virginia ambient monitoring network, 1993–2008..................................................................38

7. Semi-volatile organic compounds analyzed for in selected groundwater samples 

from the West Virginia ambient monitoring network, 1993–2008........................................40

8. Pesticides and pesticide degradates analyzed for in 77 groundwater samples from 

the West Virginia ambient monitoring network, 1993–2008.................................................41

9. Principal components analysis showing distribution of eigenvector loadings for 

the first two principal components for samples from the West Virginia ambient 

monitoring network, 1993–2008 ................................................................................................44
vii

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in) 2.54 centimeter (cm)

inch (in) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

yard (yd) 0.9144 meter (m)

Area

square mile (mi2

) 259.0 hectare (ha)

square mile (mi2

) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

million gallons (Mgal) 3,785 cubic meter (m3)

cubic inch (in3

) 16.39 cubic centimeter (cm3) 

Mass

ounce, avoirdupois (oz) 28.35 gram (g) 

ton per year (ton/yr) 0.9072 metric ton per year

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

°F=(1.8×°C)+32

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

°C=(°F-32)/1.8

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

(NAVD 88).

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

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

*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
Groundwater Quality in West Virginia, 1993–2008

By Douglas B. Chambers, Mark D. Kozar, Jeremy S. White, and Katherine S. Paybins

Abstract

Approximately 42 percent of all West Virginians rely 

on groundwater for their domestic water supply. However, 

prior to 2008, the quality of the West Virginia’s groundwater resource was largely unknown. The need for a statewide 

assessment of groundwater quality prompted the U.S. Geological Survey (USGS), in cooperation with West Virginia 

Department of Environmental Protection (WVDEP), Division of Water and Waste Management, to develop an ambient 

groundwater-quality monitoring program.

The USGS West Virginia Water Science Center sampled 

300 wells, of which 80 percent were public-supply wells, over 

a 10-year period, 1999–2008. Sites for this statewide ambient groundwater-quality monitoring program were selected 

to provide wide areal coverage and to represent a variety 

of environmental settings. The resulting 300 samples were 

supplemented with data from a related monitoring network of 

24 wells and springs. 

All samples were analyzed for field measurements 

(water temperature, pH, specific conductance, and dissolved 

oxygen), major ions, trace elements, nutrients, volatile 

organic compounds, fecal indicator bacteria, and radon-222. 

Sub-sets of samples were analyzed for pesticides or semivolatile organic compounds; site selection was based on local 

land use. 

Samples were grouped for comparison by geologic 

age of the aquifer. Groups included Cambrian, Ordovician, 

Silurian, Devonian, Pennsylvanian, Permian, and Quaternary 

aquifers. A comparison of samples indicated that geologic 

age of the aquifer was the largest contributor to variability in 

groundwater quality. 

This study did not attempt to characterize drinking water 

provided through public water systems. All samples were of 

raw, untreated groundwater. Drinking-water criteria apply to 

water that is served to the public, not to raw water. However, 

drinking-water criteria, including U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL), 

non-enforceable secondary maximum contaminant level 

(SMCL), non-enforceable proposed MCL, or non-enforceable 

advisory health-based screening level (HBSL), were used as 

benchmarks against which to compare analytical results. 

Constituent concentrations were less than the MCLs in 

most samples. However, some samples exceeded non-enforceable SMCLs, proposed MCLs, or advisory HBSLs. Radon-222 

concentrations exceeded the proposed MCL of 300 picocuries 

per liter (pCi/L) in 45 percent of samples, and iron concentrations exceeded the SMCL of 300 micrograms per liter (μg/L) 

in 57 percent of samples. Manganese concentrations were 

greater than the SMCL (50 μg/L) in 62 percent of samples 

and greater than the HBSL (300 μg/L) in 25 percent of the 

samples. Other sampled constituents, including organic compounds and trace elements, exceeded drinking-water criteria at 

much lower frequencies.

The radon-222 median concentrations in samples from 

Cambrian, Ordovician, Silurian, Permian, and Quaternary 

aquifers exceeded the proposed 300 pCi/L MCL. Although 

median radon concentrations for wells in Devonian, Mississippian, and Pennsylvanian aquifers were less than the proposed 

MCL, radon concentrations greater than the proposed MCL 

were measured in samples from aquifers of all geologic ages.

The median iron concentrations for samples from 

Devonian and Pennsylvanian aquifers were greater than the 

300 μg/L SMCL. Iron concentrations exceeded the SMCL 

in aquifers of all geologic ages, except Cambrian. Median 

concentrations of manganese exceeded the SMCL in samples 

from Devonian, Pennsylvanian, and Quaternary aquifers. As 

with iron, manganese concentrations were found to exceed 

the SMCL in at least one sample from aquifers of all geologic 

ages, except Cambrian. 

Pesticides were detected most frequently and in higher 

concentrations in limestone-dominated areas. Most of West 

Virginia’s agriculture is concentrated in those areas. 

This study, the most comprehensive assessment of West 

Virginia groundwater quality to date, indicates the water quality of West Virginia’s groundwater is generally good; in the 

majority of cases raw-water samples met primary drinking 

water-criteria. However, some constituents, notably iron and 

manganese, exceeded the secondary drinking-water criteria in 

more than half the samples.
2 Groundwater Quality in West Virginia, 1993–2008

Introduction

Groundwater is an important resource for the people of 

West Virginia. The use of groundwater has been most recently 

described by Atkins (2007). Approximately 70 million gallons 

of groundwater per day (Mgal/d) are withdrawn to supply the 

42 percent of all West Virginians who rely on groundwater 

for their domestic water supply, including drinking water. Of 

that 42 percent of West Virginians reliant upon groundwater 

resources for domestic water use, 23 percent obtain water 

from privately owned wells and 19 percent from public-supply 

wells. Water census data from 2004 show that industry, irrigation, commercial, and mining uses accounted for 54 million 

gallons per day (Mgal/d) in groundwater withdrawals. Commercial groundwater use, which includes restaurants and 

motels as well as churches and schools, was estimated to be 

16 Mgal/d in 2004. 

Although widely used and generally considered to be of 

good quality, West Virginia’s groundwater resources are not 

without problems. These range from “nuisance” problems, 

such as staining of fixtures by high iron and manganese concentrations, to the presence of contaminants at concentrations 

that have possible adverse human health effects. Fecal-indicator bacteria and nutrients occur in groundwater throughout 

West Virginia, indicating the susceptibility of groundwater to 

contamination from surface sources. The variability of specific 

water-quality characteristics across the State is likely attributable to regional variations in environmental setting, such as 

local lithology and principal aquifer characteristics, land use 

and land cover, well construction, and topographic setting.

Since 1993, the U.S. Geological Survey (USGS) West 

Virginia Water Science Center, in cooperation with the West 

Virginia Department of Environmental Protection (WVDEP), 

Division of Water and Waste Management, has collected 

groundwater samples in an effort to characterize the ambient 

quality of the State’s groundwater. The initial statewide ambient groundwater-quality monitoring program’s study design 

called for the collection of samples from 17 wells and 9 springs 

selected to represent the differences in hydrogeologic settings 

throughout West Virginia. However, in 1999 the approach was 

changed to improve the geographic coverage of the sampling.

Previous Investigations

An earlier statewide analysis of groundwater quality 

(Mathes and others, 1998) was conducted by analyzing existing data available in the USGS National Water Information 

System (NWIS) database and data for the 26 sites that comprised the initial statewide ambient groundwater monitoring 

network. Results of that investigation did not indicate any 

statistically significant seasonal variation in groundwater 

quality. The highest median nitrate plus nitrite concentrations were present in water from Cambro-Ordovician limestone aquifers. Median dissolved manganese concentrations 

typically exceeded the 50 micrograms per liter (μg/L) U.S. 

Environmental Protection Agency (USEPA) secondary maximum contaminany level (SMCL) (U.S. Environmental Protection Agency, 2009b) in water samples from Lower-, Middle-, 

and Upper-Pennsylvanian; Devonian; and Holocene alluvial 

aquifers. Median dissolved iron concentrations typically 

exceeded the 300 μg/L USEPA SMCL (U.S. Environmental 

Protection Agency, 2009b) in water samples from Lower- and 

Middle-Pennsylvanian and Devonian aquifers. Median dissolved concentrations of iron and manganese were greatest in 

water from shallow wells and from wells in valley settings. 

Statistically significant relations of sodium and calcium concentrations in water with well depth indicated the occurrence 

of cation- exchange processes.

McCoy and Kozar (2007) used dissolved gases in 

groundwater of West Virginia, collected as part of the statewide ambient groundwater-quality monitoring program, to 

define a relation between groundwater age and topographic 

setting in the Appalachian Plateaus Physiographic Province 

(Fenneman and Johnson, 1946); older waters were found in 

valley settings, and younger waters dominated in hilltop wells. 

A similar pattern was not found in the Valley and Ridge Physiographic Province. The dissolved gas data set also included 

methane concentrations (White and Mathes, 2006; Mathes and 

White, 2006). Methane, a combustible gas that can accumulate 

in confined spaces at explosive levels, was found in concentrations exceeding the U.S. Office of Surface Mining’s action 

level of 28 milligrams per liter (mg/L) (Eltschlager and others, 

2001) in samples from some wells, primarily in West Virginia’s southern coal fields.

Patterns of land use can affect the water quality of 

underlying aquifers. Agricultural practices in West Virginia 

are concentrated in areas of Quaternary alluvium or limestone 

lithologies with high transmissivities (Kozar and Mathes, 

2001). Much of West Virginia’s chemical industry is located in 

areas with alluvial aquifers that are very susceptible to surface 

contamination (Kozar and Mathes, 2001). Coal mining, a 

major land use in much of West Virginia, can affect groundwater quality (McAuley and Kozar, 2006). Concentrations of 

several dissolved constituents considered to be characteristic 

of coal mining, including but not limited to sulfate, iron, manganese, and total dissolved solids, were significantly higher in 

wells adjacent to mined areas (McAuley and Kozar, 2006). 

Purpose and Scope

The purpose of this report is to summarize groundwaterquality data collected as part of cooperative USGS-WVDEP 

monitoring program for public-supply wells and to examine 

relations among water-quality characteristics and the environmental setting of the sampled wells. Results from field measurements and laboratory analyses of groundwater samples are 

used to describe physical and chemical properties and concentrations of fecal indicator bacteria, major ions, nutrients, trace 

elements, and radon. Subsets of samples are further analyzed 

to determine the concentrations of pesticides, semi-volatile 
Study Area, Design, and Methods 3

organic compounds, volatile organic compounds, and dissolved gases. A summary of dissolved gas data collected as 

part of this study can be found in McCoy and Kozar (2007). 

Study Area, Design, and Methods

West Virginia lies entirely within the Appalachian 

Mountains with parts of the State in three physiographic 

provinces (Fenneman and Johnson, 1946), regions with similar 

rock types and groundwater characteristics. The western and 

central parts of the State lie within the Appalachian Plateaus 

Physiographic Province. The Appalachian Plateaus consist of 

sub-horizontal consolidated sedimentary rocks of Devonian to 

Permian age (fig. 1). These rocks have been highly dissected 

by stream erosion resulting in steep hills and deeply incised 

valleys. Valleys are filled in part with unconsolidated sediments of Quaternary age. 

The eastern part of the State lies primarily in the Valley 

and Ridge Physiographic Province, named for the series of 

northeast-southwest trending valleys and ridges formed from 

Cambrian to Silurian aquifers. These strata are consolidated 

sedimentary rocks that are extensively faulted and sharply 

folded. The Blue Ridge Physiographic Province includes only 

the very easternmost edge of the Eastern Panhandle of West 

Virginia. In contrast to the sedimentary rocks of the Appalachian Plateaus and Valley and Ridge Physiographic Provinces, 

the Blue Ridge Physiographic Province is underlain by crystalline rock. 

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Sampled wells and springs

Multiple samples

Single samples

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 1. The geology of West Virginia and locations of groundwater-quality sampling sites, wells, and springs in the West Virginia 

ambient monitoring network, 1993–2008.
4 Groundwater Quality in West Virginia, 1993–2008

Two aquifer types, unconsolidated alluvial deposits and 

sedimentary bedrock aquifers, underlie most of West Virginia 

(Kozar and Brown, 1995). The alluvial aquifers occur primarily along the Ohio and Kanawha Rivers. Seven bedrock 

aquifers, ranging in geologic age from Cambrian to Permian, 

underlie most of West Virginia (Puente, 1985). These principal 

aquifers differ in hydraulic characteristics, such as specific 

capacity, specific yield, and transmissivity (Kozar and Mathes, 

2001), and in water quality (Kozar and Brown, 1995).

One of the strongest influences on groundwater-quality 

characteristics is aquifer geology. Sites were selected in a way 

that would best represent the local environmental setting, provide the best areal coverage of the State, and represent a variety of topographic settings. The environmental settings were 

considered to be a combination of the dominant aquifer type 

and aquifer age, physiography, and topographic setting. The 

two major aquifer types in West Virginia are unconsolidated 

alluvium of Quaternary age and consolidated bedrock aquifers, 

which range from Permian- to Cambrian-aged aquifers. As 

previously mentioned, West Virginia lies in the Appalachian 

Plateaus, Valley and Ridge, and Blue Ridge Physiographic 

Provinces. Topographic settings consisted of valley, hillside, 

or hilltop settings.

Well Selection

Wells throughout West Virginia were sampled as part 

of this study (fig. 1). Wells were selected from a database of 

public-supply wells maintained by the West Virginia Bureau 

for Public Health. To provide additional geographic coverage 

in areas with few public-supply wells, domestic wells, USGS 

water-level network wells, other types of wells, or springs 

were sampled. 

Minimum criteria for a well to be considered for sampling were (1) well less than 25 years old, (2) minimum yield 

of 5 gallons per minute, and (3) adequate plumbing system for 

sampling water prior to treatment. The minimum information 

required for each well included well depth, length of casing, location (latitude/longitude), and contributing geologic 

unit (aquifer). Available well-construction information was 

recorded (age, depth, and casing length). Copies of driller’s 

logs were obtained where available. However, as these logs 

were not required throughout the majority of the period in 

which the wells were drilled they were not available for nearly 

90 percent of the wells. An on-site inspection was conducted 

to identify signs of the well for rust in the casing and adequate 

well pad construction to prevent surface contaminants entering 

the well bore. Existing submersible pumps were most commonly used for water-sample collection, but in a small number 

of wells, turbine pumps, jet pumps, or a portable submersible 

pump were used. Well and site characteristics were obtained 

during a site visit, from drilling logs, and from well-owner 

records, where available. If both the minimum criteria and the 

minimum information requirements were met, the well was 

selected for sampling.

Each year during 1999–2008, a set of 30 wells, most of 

which were public-supply wells, was selected for one-time 

sampling. The result is a dataset of 300 wells sampled over the 

10-year period, 1999–2008, since the new sampling regimen 

was implemented. Data from the 300 samples were combined 

with data from a representative sample from each of 15 wells, 

two wells were excluded due to incomplete data sets, and nine 

springs in the initial program. The representative samples were 

selected on the basis of central tendency of the sample among 

all samples from that site and completeness of data. This 

selection process yielded 324 wells of which 239 were publicsupply wells, 45 were domestic wells, and the remainder a mix 

of industrial, mining, and other uses.

Collection of Site Environmental Setting 

Information

A geographic information system (GIS) was used to 

assemble information to define the environmental setting of 

individual well sites. Each well was attributed with spatial 

data describing the geology, land cover, elevation, and other 

factors, all of which are described in detail below. 

Surficial geology for each well was determined using a 

200- or a 300-meter radius buffer around the well overlain 

with the 1:250,000-scale surficial geology data (Cardwell and 

others, 1968). The larger buffer distance was used if carbonate 

rocks were present in greater than 50 percent of a 50-meter 

well buffer. Most of the wells, 289, are completed in noncarbonate rocks, whereas 35 wells are completed in carbonate 

rocks. One lithologic unit is present in the buffer zone for 223 

wells, two lithologic units for 82 wells, three lithologic units 

for 16 wells, and four lithologic units for 3 wells.

The land-use/land-cover data used to calculate percent 

of land cover is from the National Land Cover Dataset of 

2001 (NLCD2001) (Multiple Resolution Land Characteristics Consortium, 2007). The zone of influence from land 

cover for wells in the Appalachian Plateaus of West Virginia 

is fairly constrained as a result of relatively short and limited groundwater flow paths (McAuley and Kozar, 2006). 

Thus, land-cover data from the NLCD2001 was chosen for a 

100-meter-radius buffer zone around each well sampled, with 

each land cover represented as a percentage of that 100-meter 

buffer zone. For each of the 14 land covers present in the well 

buffer zones, the maximum land cover ranges from 24 percent 

to 100 percent. The median for each land cover ranges from 

0 percent to 29 percent; only developed open space (16 percent) and forested areas (29 percent) have medians greater 

than zero. This analysis demonstrates that the land cover 

around the sampled wells tends to be fairly heterogeneous, 

biased slightly towards developed open space and forested 

land covers.

Population density is a measure of approximately how 

many people per square mile live near each well. This analysis 

used block-group population density (U.S. Census Bureau, 

2002) within a 100-meter buffer zone around each of the 
Study Area, Design, and Methods 5

wells. For each 100-meter buffer, a weighted average population density was calculated by multiplying the population 

density for each block group that intersects the buffer by its 

corresponding area within the buffer, summing the resulting 

buffer block-group populations, and dividing by the buffer 

zone. Buffer population densities for the wells range from 

4 to 3,798 people per square mile, with a median of 34 people 

per square mile and a standard deviation of 437 people per 

square mile.

The topographic setting of each well is a qualitative 

measure based on the steepness of or near the site as described 

in field notes and a well’s location on Digital Raster Graphics 

(DRGs) of USGS Topographic Maps at the 1:24,000 scale. 

Three categories are defined—valley, hillside, or hilltop. Some 

ambiguity exists in this qualitative measure, especially in the 

karst landscape of the Eastern Panhandle of West Virginia. 

Most of the wells in this study are found in valley settings 

(208), with hilltop being the next most common (87) and hillside settings the least common (29).

Physiographic province and section were generated for 

each well by intersecting the point representing the well with 

physiographic data at the 1:7,000,000 scale (U.S. Geological 

Survey, 1998), which is based on the work of Fenneman and 

Johnson (1946). The physiographic provinces are defined by 

strong similarities in topography and geology. The Appalachian Physiographic Province covers about 83 percent of West 

Virginia; 73 percent or 238 of the sampled wells are located 

in this physiographic province. Of these, 22 wells are in the 

Allegheny Mountain Section, and 216 are in the Kanawha Section. All 85 Valley and Ridge Physiographic Province wells are 

located in the Middle Section. The Blue Ridge Physiographic 

Province covers a very small territory within West Virginia, 

and only two wells are located in its Northern Section.

Wells Representing Unconsolidated Alluvial 

Aquifers

In West Virginia, alluvial aquifers of Quaternary age occur 

in river valleys of the Appalachian Plateaus and Valley and 

Ridge Physiographic provinces. In the Appalachian Plateaus, 

the greatest extent of alluvial aquifer is found in the Ohio River 

Valley. Other Appalachian Plateaus alluvial aquifers are the 

Kanawha River Valley, Monongahela River Valley, and Teays 

Valley aquifers. Smaller, isolated alluvial aquifers also occur 

in the Appalachian Plateaus. In the Valley and Ridge Physiographic Province, alluvial aquifers are found in the South 

Branch Potomac River Valley, the Greenbrier River Valley, and 

along several Potomac River Basin tributaries. 

Rivers have and continue to serve as transportation corridors. This use led to river valleys, in which alluvial aquifers 

are found, being early centers of settlement in West Virginia. 

Today, eight of West Virginia’s nine cities with populations 

greater than 15,000 (U.S. Census Bureau, 2002) and their associated industrial land uses are at least partly located in alluvial 

settings. Additionally, much of the agricultural activities in 

West Virginia’s Appalachian Plateaus occur within alluvial 

river valleys.

A total of 49 alluvial aquifer wells were sampled in West 

Virginia. Of these, 40 sampled alluvial wells were in the Appalachian Plateaus Physiographic Province and 35 of the sampled 

alluvial wells were in the Ohio River Valley (table 1). Of the 

remaining sampled Appalachian Plateaus alluvial wells, three 

were in Kanawha River Valley alluvial aquifers and one each 

in alluvial aquifers of the Little Kanawha River and Meadow 

River Valleys. Nine alluvial aquifer wells were sampled in 

the Valley and Ridge Physiographic Province, seven in the 

Potomac River Basin, and two in the Greenbrier River Valley.

Wells Representing Consolidated Bedrock 

Aquifers

Consolidated bedrock aquifers are the most common type 

of aquifer in West Virginia and, therefore, account for an overwhelming majority, 275 of 324, of the wells sampled (table 1). 

Wells in bedrock aquifers were sampled in all three of West 

Virginia’s Physiographic Provinces. The aquifers range in age 

from Permian aquifers, the youngest, to Cambrian aquifers, 

the oldest.

Permian aquifers are found in northwestern West Virginia 

in the Appalachian Plateaus Physiographic Province. Land 

cover in areas of Permian lithology is, as is true for much of 

West Virginia, predominantly forest. Land uses include oil and 

natural gas production, as well as coal mining. Permian aquifers are primarily nearly horizontal layers of shale with sandstone, limestone, and coal (Kozar and Brown, 1995). A total of 

19 wells were sampled in Permian aquifers. All Permian wells 

are in areas where sandstone is the dominant lithology. Of the 

Permian wells, 16 are in valley settings, and 3 are on hillsides.

Pennsylvanian aquifers cover a greater portion of West 

Virginia than aquifers of other ages. Pennsyslvanian-aged 

geologies, all within the Appalachian Plateaus Physiographic 

Province, include much of West Virginia’s extensive coal beds. 

The Pennsylvanian aquifers are nearly horizontal sandstone 

with shale, siltstone, coal, and limestone (Kozar and Brown, 

1995). More Pennsylvanian-aquifer wells were sampled, 142, 

than any other age class of aquifer. The Pennsylvanian aquifers 

is the only environmental setting in which hilltop wells were 

more numerous than other topographic settings. Pennsylvanian-aquifer wells were sampled in both sandstone- and shaledominated areas. Of the 106 Pennsylvanian-aquifer wells in 

sandstone-dominated areas, 57 were in hilltop settings, 11 on 

hillsides, and 38 in valleys. Hilltop settings were more numerous for the 36 wells located in shale-dominated areas as well, 

with 24 wells in hilltop settings, three on hillsides, and nine 

sampled wells in valleys.

Mississippian aquifers are primarily found in southeast 

West Virginia and straddle the transition between the Appalachian Plateaus and Valley and Ridge Physiographic Provinces. The Mississippian aquifers are “moderately folded, 

predominantly sandstone and limestone with shale” (Kozar 
6 Groundwater Quality in West Virginia, 1993–2008

Table 1. Aquifer settings represented in the design of the ambient 

groundwater water-quality network

Aquifer/setting Lithology Number of wells

Quaternary (49 wells)

Ohio River Valley Alluvium 35

Kanawha River Valley Alluvium 3

Other Appalchian Plateaus valleys Alluvium 2

South Branch Potomac River Valley Alluvium 3

Greenbrier River Valley Alluvium 2

Other Valley and Ridge valleys Alluvium 4

Permian (19 wells)

Appalchian Plateaus hillside Sandstone 3

Appalchian Plateaus valley Sandstone 16

Pennsylvanian (142 wells)

Appalchian Plateaus hilltop Sandstone 57

Appalchian Plateaus hillside Sandstone 11

Appalchian Plateaus valley Sandstone 38

Appalchian Plateaus hilltop Shale 24

Appalchian Plateaus hillside Shale 3

Appalchian Plateaus valley Shale 9

Mississippian (45 wells)

Appalchian Plateaus hilltop Limestone 3

Appalchian Plateaus hillside Limestone 2

Appalchian Plateaus valley Limestone 10

Appalchian Plateaus hillside Sandstone 1

Appalchian Plateaus valley Sandstone 4

Appalchian Plateaus hilltop Shale 1

Appalchian Plateaus hillside Shale 4

Appalchian Plateaus valley Shale 9

Appalchian Plateaus hillside Shale/sandstone 2

Appalchian Plateaus valley Shale/sandstone 8

Valley and Ridge hillside Sandstone 1

Devonian (41 wells)

Appalchian Plateaus valley Shale 6

Valley and Ridge hillside Limestone 1

Valley and Ridge hillside Sandstone 1

Valley and Ridge hillside Sandstone/limestone 2

Valley and Ridge valley Sandstone/limestone 1

Valley and Ridge hilltop Shale 6

Valley and Ridge hillside Shale 10

Valley and Ridge valley Shale 14

Silurian (8 wells)

Valley and Ridge hillside Limestone 3

Valley and Ridge valley Limestone 2

Valley and Ridge hilltop Sandstone 1

Valley and Ridge hillside Sandstone 2

Ordovician (9 wells)

Valley and Ridge hillside Limestone 1

Valley and Ridge valley Limestone 6

Valley and Ridge hillside Shale 1

Valley and Ridge valley Shale 1

Cambrian (11 wells)

Blue Ridge hillside Phyllite 1

Blue Ridge hillside Quartzite 1

Valley and Ridge hillside Dolostone 1

Valley and Ridge hilltop Limestone 3

Valley and Ridge valley Limestone 2

Valley and Ridge hillside Shale/sandstone 2

Valley and Ridge valley Shale/sandstone 1
Study Area, Design, and Methods 7

and Brown, 1995), in other words, a more complex setting 

than either the Pennsylvanian or Permian aquifers. Land cover 

is predominantly forest with areas of agriculture, especially in 

the Greenbrier River Valley and its surrounding karst terranes. 

The 45 sampled wells in Mississippian aquifers comprise 11 

combinations of physiography, lithology, and topography. Of 

the 45 wells, 44 are in the Appalachian Plateaus Province and 

only one in the Valley and Ridge Province. The 44 Appalachian Plateau wells consisted of 15 wells in limestone, 10 of 

which are in valley settings, 2 on hillsides, and 3 on hilltops; 

5 in sandstone, 4 in valleys and 1 on a hillside; 14 in shale, 9 

in valleys, 4 on hillsides, and 1 on a hilltop; and 10 wells in 

areas of mixed shale/sandstone aquifers, 8 in valleys and 2 

on hillsides. 

The Devonian aquifers are primarily in the Valley and 

Ridge Physiographic Province of West Virginia’s Eastern Panhandle and along the State’s eastern boundary with Virginia. 

However, a section of Devonian aquifers are in the Appalachian Plateaus Province in northeast West Virginia. Forested 

areas are the dominant land cover, with agricultural practices 

taking place in the valleys. Kozar and Brown (1995) described 

Devonian aquifers in West Virginia as ranging from “nearly 

horizontal” to “very folded,” depending on geologic formation or group. Lithology of Devonian aquifers also varies 

widely, with some formations dominated by shale and siltstone 

and other formations dominated by limestone and sandstone. 

Forty-one wells tapping Devonian aquifers were sampled, 35 

in the Valley and Ridge Province and 6 in the Appalachian 

Plateaus. Of the 35 Valley and Ridge wells, 30 were in shaledominated areas, 14 in valleys, 10 on hillsides, and 6 on hilltops; 3 were in areas with sandstone/limestone aquifers, 1 in a 

valley and the other 2 on hillsides; and one well each in areas 

of limestone aquifers and sandstone aquifers, both located on 

hillsides. The six wells located in the Appalachian Plateaus 

Province all tapped shale aquifers in valley settings.

In West Virginia, Silurian aquifers occur in the Valley 

and Ridge Province and primarily in the Eastern Panhandle, 

usually in narrow bands within areas dominated by Devonianaged rocks. Typically, Silurian aquifers consist of highly 

folded limestone, sandstone, and shale (Kozar and Brown, 

1995). Land cover and land use are similar to those in the surrounding Devonian-dominated areas. Samples were collected 

from eight Silurian aquifer wells, three in hillside limestone 

settings, two in limestone-dominated valleys, two in sandstone 

hillsides, and one on a sandstone-dominated hilltop.

The Ordovician aquifers of West Virginia are in the Valley and Ridge Province, with the greatest extent of Ordovician lithology found in the easternmost portion of the Eastern 

Panhandle. West Virginia’s Ordovician aquifers include karst 

terranes, these being most common in the State’s Eastern Panhandle. Land uses in this portion of West Virginia are dominated by agriculture but this area is also experiencing rapid 

residential development. The Ordovician aquifers of West 

Virginia consist of highly folded beds of limestone, shale and 

sandstone (Kozar and Brown, 1995). Nine wells in Ordovician 

aquifers were samples, six in limestone valley settings, one 

on a limestone hillside, one shale hillside, and one in a shale 

valley setting.

The oldest aquifers in West Virginia are the Cambrian 

aquifers, located in the easternmost part of the State. West 

Virginia’s Cambrian aquifers occur in both the Valley and 

Ridge and the Blue Ridge Provinces. Land cover in the Valley 

and Ridge portion of Cambrian lithology is similar to land 

cover in areas of Ordovician lithology. However, forest land 

cover dominated the Blue Ridge Province portion of Cambrian lithology. The Cambrian aquifers are highly folded and 

dominated by limestone or shale and sandstone (Kozar and 

Brown, 1995). Water was collected from 11 Cambrian-aquifer 

wells, 9 in the Valley and Ridge Province and 2 in the Blue 

Ridge Province. Environmental settings for Valley and Ridge 

Province wells included three wells in limestone hilltop settings, two wells in limestone valley settings, two wells in shale 

and sandstone hillside settings, and one well each in shaleand-sandstone valley and dolostone hillside settings. Both 

of the Blue Ridge Province wells are in hillside settings, one 

located in an area dominated by phyllite and the other in an 

area dominated by quartzite.

Distribution of Wells among Environmental 

Settings

The distribution of samples among the environmental 

settings, especially combinations of consolidated or unconsolidated aquifers and the geologic age of the aquifer, is uneven 

(table 2). Unconsolidated alluvial aquifers of Quaternary age 

represent less than 3 percent of the total area of West Virginia, 

yet more than 15 percent of all samples were collected in this 

setting. Similarly, Cambrian bedrock aquifers represent less 

than 1 percent of West Virginia’s total area, yet more than 

3 percent of all samples were from this setting. In contrast, 

Permian bedrock aquifers represent more than 20 percent of 

West Virginia; however, less than 6 percent of all samples 

were collected in this environmental setting. These disparities 

in sampling rates among environmental settings were largely 

driven by the distribution of population which is a primary 

factor in the distribution of wells.

Well Sampling

Groundwater samples were collected during the late 

spring and summer months. Prior to sampling, wells were 

purged to remove stagnant water from the casings and ensure 

that representative water samples were collected from the 

target aquifer. A minimum of one casing volume was purged 

from most wells; high-use public-supply wells that did not 

require purging or very low-yielding wells that would not 

recover from purging were pumped until field measurements 

stabilized. Field measurements of characteristics, including 

dissolved oxygen, pH, specific conductance, water temperature, and turbidity, were monitored during purging by using 

a multi-parameter water-quality meter, which was calibrated 
8 Groundwater Quality in West Virginia, 1993–2008

Table 2. The distribution of samples by geologic age of aquifer.

Geologic age 

of aquifer

Area, in 

square miles

Percent of 

total area

Number of 

samples

Percent of 

samples

Samples per 

square mile

Cambrian 228 0.9 11 3.4 0.048

Ordovician 381 1.6 9 2.8 0.024

Silurian 478 2.0 8 2.5 0.017

Devonian 3,473 14.3 41 12.7 0.012

Mississippian 2,611 10.8 45 13.9 0.017

Pennsylvanian 11,477 47.4 142 43.8 0.012

Permian 4,933 20.4 19 5.9 0.004

Quaternary 621 2.6 49 15.1 0.079

daily. Water level was also monitored where possible. Sample 

tubing typically was connected to a 3⁄4-in. hose bib as close to 

the well head as possible, and pumps were kept on to prevent 

contamination from plumbing or back flow from holding 

tanks. Existing plumbing and well-casing materials included, 

but were not limited to, steel, galvanized steel, copper, polyvinyl chloride (PVC), and other plastics. The purging procedure 

prescribed was assumed to have prevented contamination from 

plumbing materials. Samples were collected after field measurements stabilized, according to standard USGS protocols 

for the collection of water-quality data (U.S. Geological Survey, 2006). To prevent environmental contamination, samples 

were typically collected and processed inside a mobile field 

laboratory or a portable chamber assembled near the well. 

All samples were analyzed for field measurements, alkalinity, fecal indicator bacteria (fecal coliforms, total coliforms, 

and Escherichia coli), major ions, trace elements, nutrients, 

volatile organic compounds (VOCs), and Radon-222 (table 3). 

Field determinations, including field measurements, alkalinity, 

and biological indicators, were processed on site according to 

standard protocols (U.S. Geological Survey, 2006). Subsets of 

samples were collected and analyzed for pesticides or semivolatile organic compounds. 

Samples were processed according to standard USGS 

protocol (Wilde and others, 2004). Samples for analysis of 

dissolved major ions were filtered at 0.45 micrometer. Trace 

element analyses were performed on unfiltered samples. Nutrient analyses were performed on both filtered and unfiltered 

samples. Samples were then shipped daily by overnight courier to USGS laboratories for analysis.

Statistical Methods

Descriptive and summary statistics were calculated using 

Spotfire S-PLUS 8.1 statistical and graphing software (TIBCO 

Software, Inc., 2008). Descriptive and summary statistics for 

censored data sets, those with values less than the reporting 

level, were calculated using the Regression on Order Statistics (ROS) and adjusted maximum likelihood estimation 

(AMLE) techniques (TIBCO Software Inc., 2008). Statistics 

were not calculated for sample sets of less than 10 items. 

Kruskal-Wallace rank test or ANOVA were used, as appropriate, for comparisons of medians among groups. A Tukey’s 

Honest-Significant-Difference post hoc test was used for 

multiple comparisons. 

Relations among several variables were analyzed through 

Principal Components Analysis (PCA). Analysis of groundwater-quality data for geochemical processes was performed 

using the PCA routine in SAS (SAS Institute Inc., 1999). PCA 

of groundwater-quality and environmental-setting data was 

performed in S-PLUS. 

Quality Assurance

Quality-assurance samples, blanks and replicates, were 

collected during each year of sampling. Blank samples are 

used to determine the extent to which sampling procedures 

may contaminate samples, thereby biasing analytical results. 

Replicate samples are used to determine the variability inherent in the collection and analysis of environmental samples. 

Together, blank and replicate samples can be used to characterize the accuracy and precision of water-quality data. 

All quality-assurance samples were collected and processed 

according to protocols described in the USGS National Field 

Manual for the Collection of Water-Quality Data (U.S. Geological Survey, 2006).

Blank Samples

Blank samples consist of water of known quality, certified to not contain the constituents of interest in concentrations 

greater than a stated level, completely or partially processed in 

the same manner as an environmental sample. Any departure 

of the blank sample’s analytical results from the blank water’s 

known quality is an indication of contamination through 

handling, collecting, or processing the sample. Equipment 
Quality Assurance 9

Table 3. Water-quality characteristics, major ions, metals, trace elements, nutrients, radon-222, and fecal indicator bacteria analyzed 

for in groundwater samples from the West Virginia ambient monitoring network, 1993–2008.

[RL, reporting limit; NA, not applicable; °C, degrees Celsius; μS/cm, microsiemens per centimeter, mm/Hg, millimeters in mercury; mg/L, milligrams per 

liter; NTU, nephelometric turbidity units; CaCO3, calcium carbonate; H+, hydrogen ion; wf, filtered water sample; wu, unfiltered sample; inflect, inflectionpoint titration; recov, recoverable; ANC, acid neutralizing capacity; ROE, residue on evaporation; μg/L, micrograms per liter; N, nitrogen; NH4

+

, ammonium; 

NO3+NO2, nitrate plus nitrite; P, phosphorus; pCi/L, picocuries per liter; M-FC, fecal coliform membrane filtration procedure; MPN, most probable number; 

cfu, colony-forming unit; NA-MUG, nutrient agar-4-methylumbelliferyl-b-D-glucuronide; M-Endo, modified Endo’s agar]

Constituent or property RL Constituent RL

Water temperature, °C NA Arsenic, wu, μg/L 0.2–4

pH, standard units NA Barium, wu, recov μg/L 0.6

Specific conductance at 25°C, μS/cm NA Beryllium, wu, recov μg/L 0.4–1

Air pressure, mm/Hg NA Cadmium, wu, μg/L 0.01–0.5

Dissolved oxygen, mg/L NA Chromium, wu, recov μg/L 0.4–1

Turbidity, NTU NA Iron, wu, recov μg/L 2-6

Alkalinity, inflect, field mg/L CaCO3 1 Lead, wu, recov μg/L 0.6–2

Acidity, heated, mg/L as H+ 0.1 Manganese, wu, recov μg/L 0.2–1

Acidity, mg/L, as CaCO3 1 Mercury, wu, recov μg/L 0.01–0.1

Bicarbonate, mg/L 1 Nickel, wu, recov μg/L 0.12–1

Carbonate, mg/L 1 Selenium, wu, μg/L 0.08–4

Calcium, wu, recov, mg/L 0.04 Thallium,wu, μg/L 0.08–2

Magnesium, wu, recov, mg/L 0.008 Zinc, wu, recov μg/L 1–2

Potassium, wu, recov, mg/L 0.1 Ammonia, mg/L as N 0.01–0.04

Sodium, wu, recov, mg/L 0.24–0.05 Ammonia, mg/L NH4

+ NA

ANC, mg/L of CaCO3 5 NO3

+NO2, mg/L as N 0.02–0.06

Bromide, wf, mg/L 0.02–0.2 Nitrate, mg/L as N NA

Chloride, wf, mg/L 0.2 Nitrite, mg/L as N 0.002–0.01

Fluoride, wu, mg/L 0.1–0.12 Total nitrogen, mg/L 0.06

Fluoride, wf, mg/L 0.1 Orthophosphate, mg/L as P 0.006–0.03

Sulfate, wf, mg/L 0.07–0.9 Phosphorus, mg/L 0.004–0.02

Residue, ROE at 105°C, mg/L 13 Radon-222, pCi/L 10–30

Residue, ROE at 180°C, mg/L 10 E. coli, Colilert, MPN/100 mL 1

Organic carbon, mg/L 0.1–0.4 E. coli, NA-MUG, cfu/100 mL 1

Aluminum, wu, recov μg/L 2–4 Fecal coliform, M-FC, cfu/100 mL 1

Antimony, wu, μg/L 0.1–1 Total coliform, Colilert, MPN/100 mL 1

Total coliform, M-Endo, cfu/100 mL 1
10 Groundwater Quality in West Virginia, 1993–2008

and field blank samples were collected throughout the study 

period. Equipment blank samples, processed by pumping 

blank water through sampling equipment in a laboratory setting, were used to determine if either equipment or cleaning 

procedures were a potential source of contaminants. Field 

blank samples, pumped through sampling equipment at field 

sites prior to collection of an environmental sample, were used 

to identify possible additional sources of contamination in the 

sampling procedure. Types of blank water used in this study 

included inorganic blank water and pesticide-grade, nitrogenpurged VOC-free blank water; both blank-water types are 

certified by the USGS National Water Quality Laboratory. 

Analysis of blank samples varied with blank purpose. 

Each year prior to sampling, an equipment blank sample was 

processed with inorganic blank water in the West Virginia 

Water Science Center laboratory. These blank samples were 

analyzed for major ions, metals, trace elements, and nutrients. 

Field blank samples were analyzed for the same suite of constituents. In addition, field blank samples of pesticide-grade, 

nitrogen-purged, VOC-free blank water were processed on site 

and analyzed for pesticides or VOC’s.

In general, results of blank-sample analyses indicated 

that equipment cleaning and sampling procedures were sufficient to prevent sample contamination. However, some blank 

samples contained detectable concentrations of target analytes. 

These are discussed by analyte or analyte class in the following paragraphs.

Aluminum was detected in both blank samples from 

1999, at concentrations of 4 and 7 micrograms per liter (μg/L). 

The majority of concentrations for environmental samples, 

19 of 30, were below the higher blank concentration. Furthermore, the median aluminum concentration in environmental 

samples from 1999 was 5 μg/L and for all other sampling 

periods combined it was below detection levels that ranged 

from 2 to 4 μg/L. It seems likely that analyses for aluminum 

for all environmental samples collected in 1999 were biased 

high; therefore, aluminum results for environmental samples 

collected during this period were excluded from the analysis 

of ambient groundwater data. Aluminum was not detected in 

blank samples from any other year.

Calcium was detected in three blank samples, one each 

from 1999, 2005, and 2006. The calcium detection in 1999 

was 0.02 mg/L, the laboratory reporting level for that year. 

The detection of calcium in blank samples from 2005 and 

2006 were both estimated values, 0.02 and 0.03 mg/L, respectively. The lowest concentration in any environmental sample 

was 0.7 mg/L, and the median value for all environmental 

samples was 31.3 mg/L. It is unlikely blank contamination significantly influenced the analysis of any environmental sample 

or the interpretation of the data.

Sodium was detected in a blank sample in 1999 at a 

concentration of 0.2 mg/L, the laboratory reporting level. 

The lowest value in any environmental sample that year was 

6.8 mg/L. It is unlikely this low-level of sodium detected in 

one blank sample significantly influenced results for environmental samples collected during this year.

Ammonia was detected at the 0.01 mg/L laboratory 

reporting level in approximately 25 percent of all blank samples. The persistent detection of ammonia at the threshold of 

quantification indicates a persistent source of contamination. 

However, the mean concentration in environmental samples 

was an order of magnitude greater, 0.22 mg/L. The low-level 

concentrations of ammonia detected in blank samples were 

not considered to have influenced the interpretation of nitrate 

and nitrite data, neither of which were detected in any blank 

sample. No other nutrient species, nitrogen or phosphorus, was 

detected in any blank sample.

Concentrations of pesticides were detected in only one 

blank sample analyzed for these compounds. Both deethylatrazine and prometon were detected in a blank sample collected 

in 2000. Deethylatrazine, an atrazine degradation product, 

was detected at an estimated concentration 0.002 μg/L and 

prometon was remarked with an “M” code, indicating the 

compound’s presence had been verified but not quantified. This blank sample was collected following equipment 

cleaning after sampling a well where multiple pesticides 

were detected, including deethylatrazine and atrazine. The 

compounds detected in the blank sample may represent contamination remaining following cleaning. However, neither 

deethylatrazine nor prometon were detected in subsequent 

pesticides samples. 

A detectable concentration of a target compound was 

found in only one VOC blank sample. Trichloromethane was 

detected in a blank sample from 2007 at a concentration of 

0.6 μg/L. Trichloromethane was detected in an environmental 

sample from the previous day, albeit at a lower concentration, 

0.1 μg/L. Trichloromethane was not detected in any of the 

next eight environmental samples collected. The detection of 

trichloromethane in this blank sample appears to be anomalous 

and did not affect results for any environmental samples.

Replicate Samples

Comparison of results among replicate samples can 

provide insight into the sources of variability that are inherent 

in sample collection, processing, and analysis. Sample collection protocols (U.S. Geological Survey, 2006) require that 

environmental samples be collected after three casing volumes 

are purged from the well and field measurements of water 

temperature, specific conductance, dissolved oxygen, pH, and 

turbidity have stabilized. Once these criteria have been met it 

is assumed that the water being sampled is both representative of the aquifer and constant through the duration of sample 

collection and that any variability among the main sample and 

replicate sample is primarily attributable to sample processing 

and analysis (Koterba and others, 1995). 

Variability for a replicate sample pair was quantified by calculating the relative percent difference (RPD) of 
Groundwater Quality In West Virginia 11

the samples. The RPD was calculated using the following 

formula: 

R1 − R2

R1 + R2

2

⎛

⎝

⎜ ⎞

⎠

⎟

⎛

⎝

⎜

⎜

⎜

⎞

⎠

⎟

⎟

⎟

×100 ,

Where 

R1 is the concentration of the analyte in the first 

replicate sample and 

R2 is the concentration of the analyte in the 

second replicate sample.

Generally, concentrations in replicate sample pairs differed by small amounts, typically less than 15 RPD. Many of 

the replicate sample pairs with RPDs greater than 15 were for 

comparisons of estimated values or for values very close to 

the reporting level, where a difference of the smallest reported 

increment of change is greater than 15 RPD and may be attributable to rounding error. However, some constituent replicate 

sample pairs that differed by more than 15 RPD that did not fit 

these criteria and are discussed by analyte below.

Three lead replicate sample pairs, two collected in 2006 

and one collected in 2007, differed by more than 15 RPD, 

from 15.4 to 35.3 RPD. Laboratory quality-assurance data 

from the period when the two 2006 replicate sample pairs 

were analyzed indicate method spike recoveries, an indication of the ability to accurately measure a sample of known 

concentration, were greater than normal for this analytical run, perhaps contributing to increased sample variability. The difference in the 2007 replicate sample pair most 

likely reflects cumulative sample processing and analytical 

variability contributions.

Replicate chromium samples were generally in good 

agreement, with RPDs less than 15, with the exception of two 

replicate sample pairs collected in 2006. The chromium concentrations in these sample pairs, differing by 16 and 40 RPD, 

were reported using an interim reporting level that was subsequently increased to a level that resulted in these sample pairs 

being reported as either “less than” or “estimated” values. 

Replicate nutrient samples were within acceptable ranges 

of differences. The only occurrences of RPDs greater than 15 

was for very low–level concentrations, where the concentration in one replicate sample was below the reporting level 

and in the other sample was either minimally greater than the 

reporting level or an estimated value.

Groundwater Quality In West Virginia

Concentrations of water-quality constituents were compared to existing regulatory and non-regulatory water-quality 

criteria, either USEPA primary and secondary maximum 

contaminant levels (MCLs and SMCLs) (U.S. Environmental 

Protection Agency, 2009b) or health-based screening levels 

(HBSLs; Toccalino and others, 2008). These criteria are applicable to finished drinking water, not the raw water samples 

collected for this study. These criteria are used to provide a 

benchmark against which water-quality characteristics and 

constituents are compared and may be useful for resource 

managers charged with protecting and managing drinkingwater resources. For example, the comparisons can provide 

an indication of when contaminant concentrations in ambient 

water resources may warrant further study or monitoring. The 

use of comparisons implies neither compliance nor non-compliance with drinking-water standards. The sample data for 

this study can be accessed through the USGS NWISWeb portal for West Virginia water-quality samples (http://waterdata.

usgs.gov/wv/nwis/qw/). 

Water-Quality Characteristics 

Specific conductance and pH of groundwater provide a 

general indication of water quality and often bear a signature 

of the source aquifer. These characteristics also influence other 

chemical constituents present by affecting solubility, partitioning, and valence states. Although much of the variability of 

specific conductance and pH in groundwater is due to natural 

factors, anthropogenic activities, such as coal mining, also 

contribute to this variability (McAuley and Kozar, 2006). 

Specific Conductance

Specific conductance, the ability of water to conduct an 

electrical current, is dependent upon the amount of dissolved 

ions present in the water. In this study, specific conductance 

ranged from 29 microsiemens per centimeter (μS/cm) to 

2,610 μS/cm with a median value of 444 μS/cm. The median 

value for this study closely agrees with a median value of 

417 μS/cm for samples from 2,137 domestic wells in the principal aquifers of the United States (DeSimone, 2008). Median 

values for specific conductance did not differ greatly among 

the aquifers (fig. 2). In a comparison of sets of more than 10 

samples, each set representing the geologic age of aquifers 

(Cambrian, Devonian, Mississippian, Pennsylvanian, Permian, 

and Quaternary), the median value for specific conductance 

was highest, 648 μS/cm, for wells in Cambrian aquifers and 

lowest, 283 μS/cm, for wells in Devonian aquifers.

pH

The measure of acidity or alkalinity of a solution, pH, 

plays an important role in the solubility of metals. The pH of 

samples collected in this study ranged from 4.2 to 10.0, with 

an overall median of 7.1. pH did not differ greatly with respect 

to geologic age, with the exception of Permian aquifers; 

median values of pH ranged from 6.9 in samples from Cambrian aquifers and Quaternary aquifers to about 8.4 in samples 

from Permian aquifers (fig. 3). The USEPA has established 

a SMCL for pH. The SMCL is a recommendation, based on 
12 Groundwater Quality in West Virginia, 1993–2008 Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

Specific conductance, in microsiemen per centimeter

104

103

102

101

11 9 8 41 45 142 19 49

Geologic age

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 2. Distribution of specific conductance values in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age of the aquifers, 1993–2008. Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

pH, in standard units

11 9 8 41 45 142 19 49

Geologic age

4

5

6

7

8

9

10

11

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency upper secondary 

maximum contaminant level

U.S. Environmental Protection 

Agency lower secondary 

maximum contaminant level

Individual value

Figure 3. Distribution of pH in groundwater samples from the West Virginia ambient monitoring network, grouped by geologic 

age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) recommended upper and lower values for the 

secondary maximum contaminant level are shown.
Groundwater Quality In West Virginia 13

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

pH, in standard units

4.2–6.5

6.6–8.5

8.6–10.0

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 4. Distribution of pH values for all groundwater samples from the West Virginia ambient monitoring network, 1993–2008.
14 Groundwater Quality in West Virginia, 1993–2008

aesthetic effects, primarily taste, that ideally pH would fall 

within the range of 6.5 to 8.5 (U.S. Environmental Protection Agency, 2009b). Most samples, 77 percent, fell within 

the USEPA recommended SMCL range (U.S. Environmental 

Protection Agency, 2009b) with 13 percent of samples falling 

below the recommended minimum of 6.5 and 10 percent 

exceeding the recommended maximum of 8.5 (fig. 4).

Dissolved Oxygen and Temperature

Dissolved oxygen concentration and water temperature 

were measured primarily to monitor stability of water-quality 

characteristics during well purging and to ensure that the 

well was adequately purged and the well bore contained only 

water from the surrounding aquifer at the time of sample 

collection. 

Dissolved oxygen in groundwater is from recharge of the 

aquifer with oxygenated water. Over time, dissolved oxygen can be depleted due to reactions with oxidizable matter 

(Hem, 1986). However, dissolved oxygen concentrations in 

groundwater vary, in part due to availability of oxidizable 

matter, recharge rate, and residence time in the aquifer. In 

this study, dissolved oxygen concentrations ranged from less 

than (<) 1 mg/L to 13 mg/L, with a median concentration of 

<1 mg/L. Dissolved oxygen concentrations did vary by geologic setting, with median concentrations less than 2 mg/L in 

all geologies, except those dominated by limestone, dolostone, 

or mixed limestone and sandstone surficial lithologies, where 

median concentrations were 5.5 mg/L, 5.8 mg/L (one sample 

only), and 4.9 mg/L, respectively. 

Water temperature ranged from 6.5°C to 21.5°C, with a 

median for all samples of 13.8°C. No pattern in differences 

among environmental settings was noted. 

Major Ions

The major ions calcium, magnesium, potassium, sodium, 

bicarbonate from field alkalinity, chloride, and sulfate exert a 

strong influence on water quality and geochemical processes. 

Calcium

Calcium (Ca) is the most common alkaline-earth element and a major component of many common minerals 

(Hem, 1985). Calcium concentrations ranged from 0.7 mg/L 

to 286 mg/L (fig. 5, table 4). Samples from wells that tap 

Cambrian aquifers had the highest median Ca concentration 

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Calcium, in milligrams per liter

11 9 8 41 45 142 19 49

Geologic age

10-1

100

101

102

103

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 5. Distribution of calcium concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008.
Groundwater Quality In West Virginia 15

Table 4. Statistical summary of major ions for groundwater samples from West Virginia ambient monitoring network, 1993–2008.

[mg/L, milligram per liter; SMCL, secondary maximum contaminant level (U.S. Environmental Protection Agency, 2009b); <, less than; NA, not applicable; 

--, not reported]

Major ions Reporting 

units

Method 

reporting 

level

Minimum 

concentration

Maximum 

concentration

Median 

value

SMCL

SMCL value

Samples 

exceeding 

SMCL 

Calcium, unfiltered, recoverable mg/L 0.04 0.70 286 31.3 NA --

Magnesium, unfiltered, recoverable mg/L 0.08 0.10 68.3 6.4 NA --

Potassium, unfiltered, recoverable mg/L 0.08 <0.1 16 1.4 NA --

Sodium, unfiltered, recoverable mg/L 0.1–0.24 0.20 475 27 NA --

Bicarbonate, filtered mg/L 1 <1 829 191 NA --

Chloride, filtered mg/L 0.20 <0.2 736 16.6 250 4

Sulfate, filtered mg/L 0.07–0.9 <0.07 767 14.7 250 9

(85 mg/L). The lowest median Ca concentration was in 

samples from wells in Permian aquifers (median 14 mg/L). 

The highest measured concentration, 286 mg/L, was in a 

sample from a well in the Pennsylvanian-aged Monongahela 

Group aquifer.

Magnesium

Magnesium is similar to calcium in many aspects but 

differs significantly from calcium in geochemical behavior 

(Hem, 1985). Magnesium values for all samples ranged from 

0.1 mg/L to 68.3 mg/L (fig. 6; table 4). Median values ranged 

from 2.7 mg/L for wells in Permian aquifers to 22 mg/L for 

wells in Cambrian aquifers. 

Potassium

Potassium is an essential nutrient and is a limiting 

resource in some ecosystems. Overall, potassium concentrations ranged from values less than the reporting level of 

0.08 mg/L (minimum value of <0.1 mg/L) to 16 mg/L with a 

median value of 1.4 mg/L (table 4). The highest median value 

for potassium was 1.80 mg/L for samples from Cambrian 

aquifers (fig. 7). Wells completed in Mississippian aquifers 

had the lowest median potassium value, 0.71 mg/L. 

Sodium

Sodium is the most abundant alkali-metal (Hem, 1985). 

Sodium concentration varied greatly within and among wells 

representing aquifers of different geologic ages; concentrations in samples from Pennsylvanian aquifers span the entire 

range from 0.2 mg/L to 475 mg/L (fig. 8; table 4). The median 

sodium concentration was lowest in Cambrian aquifers 

(6.39 mg/L), and the median concentration of sodium was 

highest in Permian aquifers (130 mg/L).

Bicarbonate from Field Alkalinity

Dissolved inorganic carbon in groundwater is result of 

the dissolution of atmospheric and soil-zone carbon dioxide 

(CO2), as well as reactions with carbonate rocks (Hem, 1985). 

This dissolved inorganic carbon as bicarbonate ions, carbonate ions, and free carbon dioxide can reach equilibria and 

constitute a buffer system that is resistant to changes in pH 

(Wetzel, 2001). The proportions of bicarbonate, carbonate, and 

free carbon dioxide in water is closely linked to pH. Below a 

pH of about 4.3, only free carbon dioxide and carbonic acid 

exist. At a pH of approximately 4.3 bicarbonate increases and 

is the dominant form of dissolved inorganic carbon between 

pH 7 and pH 9 (Wetzel, 2001). At a pH of approximately 8.3 

the proportion of carbonate ions starts to increase, and at pH 

values greater than 9 carbonate becomes the dominant form of 

dissolved inorganic carbon. 

Bicarbonate concentrations were determined by field 

titrations for alkalinity. Alkalinity is the capacity of water to 

neutralize an acid and is expressed in mg/L of calcium carbonate (CaCO3

). Although noncarbonate species can contribute to 

alkalinity, Hem (1985) stated that with some rare exceptions 

“the alkalinity of natural waters can be assigned entirely to 

dissolved bicarbonate and carbonate without serious error.”

The bicarbonate ion was the prevalent form of dissolved 

inorganic carbon in all samples. This is not surprising given 

the range of pH for all samples was from 4.1 to 10. Carbonate 

was detected in less than 3 percent of samples. Both the low 

and high bicarbonate concentrations for this study, less than 1 

and 826 mg/L, were measured in samples from wells in Pennsylvanian aquifers (fig. 9; table 4). Wells in Devonian aquifers 

had the lowest median bicarbonate, 144 mg/L, of the geologic 

age classes. The highest median bicarbonate was measured in 

water samples from Cambrian aquifers and Ordivician aquifers, 354 mg/L and 356 mg/L, respectively. Additionally, the 

greatest difference in median alkalinity was between sandstone 

and limestone settings.
16 Groundwater Quality in West Virginia, 1993–2008 Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

Magnesium, in milligrams per liter

80

60

40

20

0

11 9 8 41 45 142 19 49

Geologic age

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 6. Distribution of magnesium concentrations in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age of the aquifers, 1993–2008. Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

Potassium, in milligrams per liter

11 9 8 41 45 142 19 49

Geologic age

10-2

10-1

100

101

102

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 7. Distribution of potassium concentrations in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age of the aquifers, 1993–2008.
Groundwater Quality In West Virginia 17

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Sodium, in milligrams per liter

103

101

102

100

10-1

11 9 8 41 45 142 19 49

Geologic age

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 8. Distribution of sodium concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. Cambrian Ordovician Silurian Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Bicarbonate, in milligrams per liter

900

800

600

400

700

500

300

200

100

0

11 9 8 41 45 142 19 49

Geologic age

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Individual value

Figure 9. Distribution of bicarbonate in groundwater samples from the West Virginia ambient monitoring network, grouped by 

geologic age of the aquifers, 1993–2008.
18 Groundwater Quality in West Virginia, 1993–2008

Chloride

Chloride, the most abundant halide (Hem, 1985), ranged 

in concentration from less than the 0.2 mg/L minimum reporting level to 736 mg/L with a median value of 16.6 mg/L 

(table 4). Most wells, 80 percent, had chloride values from 

1.8 mg/L to 77 mg/L. Median values, by geologic ages of 

aquifers, ranged from 6.6 mg/L for wells in Devonian aquifers 

to 28 mg/L for wells in Quaternary aquifers (fig. 10). 

The SMCL for chloride is 250 mg/L (U.S. Environmental 

Protection Agency, 2009b). Samples from four wells exceeded 

this concentration. All four were from areas of Pennsylvanian 

aquifers.

Sulfate

In West Virginia pyrite-bearing rock formations are 

a major source of sulfate in groundwater. MacAuley and 

Kozar (2006) found groundwater sulfate concentrations to be 

increased in mined areas of West Virginia’s Northern Appalachian Coal Basin. 

Although sulfate concentrations ranged from less than a 

reporting level of 0.07 mg/L to 767 mg/L with a median value 

of 14.7 mg/L for all samples, most wells (80 percent) had 

sulfate concentrations of 0.3 mg/L to 86 mg/L. Median sulfate 

concentrations varied widely by geologic age of the aquifers, 

from a low of 6.7 mg/L for wells in Pennsylvanian aquifers to 

58.6 mg/L for wells in Quaternary aquifers (fig. 11). Sulfate 

concentrations exceeding the SMCL of 250 mg/L (U.S. Environmental Protection Agency, 2009b) were found in samples 

from nine wells (table 4). 

Water Types

Natural waters can be classified by “water type” on the 

basis of major-ion composition. Water samples with a specific cation or anion constituting more than one-half the total 

cations or anions can be classified by water type, calcium 

carbonate type water, for example (Hem, 1985). However, 

waters in which no single cation or anion constitutes greater 

than one-half of the total cations or anions are classed as 

mixed-type waters (Hem, 1985). Samples from aquifers classified by geologic age typically reflect a signature characteristic of the rock type, although the rock-type signatures may 

overlap broadly. Calcium was the dominant cation in most 

samples from wells in Quaternary aquifers (fig. 12A); the 

dominant anion in most samples from Quaternary aquifers was 

bicarbonate with some samples having a sulfate or chloride 

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Chloride, in milligrams per liter

11 9 8 41 45 142 19 49

Geologic age

10-2

10-1

100

101

102

103

104

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Individual value

Figure 10. Distribution of chloride concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) secondary maximum 

contaminant level of 250 milligrams per liter for finished drinking water is shown.
Groundwater Quality In West Virginia 19

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Sulfate, in milligrams per liter

11 9 8 41 45 142 19 49

Geologic age

10-2

10-1

100

101

102

103

104

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Individual value

Figure 11. Distribution of sulfate concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) secondary maximum 

contaminant level of 250 milligrams per liter for finished drinking water is shown.

signature. Samples from wells in Cambrian, Ordovician, and 

Silurian aquifers, which are predominantly limestone rocks in 

West Virginia, were almost uniformly a calcium bicarbonate 

type water (fig. 12B). Limestone is primarily calcite, which is 

CaCO3 (Hem, 1985). Water types from wells in Devonian aquifers were typically either calcium bicarbonate or magnesium 

bicarbonate (fig. 12C). Samples from Mississippian aquifers 

were primarily calcium bicarbonate water with some sodium/

potassium carbonate water (fig. 12D). The strong calcium 

carbonate signature is likely due to the many Mississippian 

limestone formations present in West Virginia. Water samples 

from wells in Pennsylvanian aquifers, representing seven formations, were highly variable with no strong signature of water 

type (fig. 12E). Water samples from wells in Permian aquifers 

(fig. 12F) were either a calcium bicarbonate type or a sodium 

bicarbonate type. 

Nutrients

All life requires several elements; these “essential” 

nutrients are foundations of the cells that constitute living 

organisms. Of the essential nutrients, nitrogen and phosphorus 

are often limiting nutrients, available at proportionately lower 

concentrations that limit growth and production. Nutrients are 

derived from mineral sources as well as organic matter, including plant and animal matter, excreted waste, and atmospheric 

deposition of combustion by-products. To increase yields, 

nitrogen and phosphorus, along with potassium, are often 

added to croplands as fertilizers. Although much of West Virginia receives very little nitrogen or phosphorus from farm or 

non-farm fertilizers, some areas of West Virginia receive high 

rates of animal-manure fertilizer application. More than 6,000 

kilograms per square kilometer of nitrogen from animal manure 

was applied to agricultural areas and grasslands in the counties 

of the Eastern Panhandle in 1997 (Ruddy and others, 2006). 

Application of farm and non-farm nitrogen fertilizers decreased 

throughout much of West Virginia from 1987 to 1997, whereas 

application of nitrogen as animal manure increased in many 

areas of the State during the same period. Much of West Virginia lies in an area that receives high loads of nitrogen from 

atmospheric deposition, greater than 400 kilograms per square 

kilometer (Ruddy and others, 2006). Regardless of the source, 

nutrients can make their way into groundwater.
20 Groundwater Quality in West Virginia, 1993–2008

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

A. Quaternary aquifers

20

40

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

B. Cambrian, Ordovician, and Silurian aquifers

20

40

EXPLANATION

Cambrian

Ordovician

Silurian

Figure 12. Piper trilinear plots of 

indicating major ion composition of 

groundwater samples from the West 

Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 

1993–2008: A, Quaternary aquifers; 

B, Cambrian, Ordovician, and Silurian 

aquifers; C, Devonian aquifers; D, 

Mississippian aquifers; E, Pennsylvanian 

aquifers; and F, Permian aquifers.
Groundwater Quality In West Virginia 21

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

C. Devonian aquifers

20

40

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

D. Mississippian aquifers

20

40

Figure 12. Piper trilinear plots of 

indicating major ion composition of 

groundwater samples from the West 

Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 

1993–2008: A, Quaternary aquifers; B, 

Cambrian, Ordovician, and Silurian 

aquifers; C, Devonian aquifers; D, 

Mississippian aquifers; E, Pennsylvanian 

aquifers; and F, Permian aquifers.

—Continued
22 Groundwater Quality in West Virginia, 1993–2008

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

E. Pennsylvanian aquifers

20

40

Percent

Calcium

60

40

20

0

Chloride, fluoride, nitrite plus nitrate

0

20

40

60

80

100

Sulfate

Percent

100

20

0

Carbonate plus bicarbonate

100

80

60

40

20

0

80

60

40

20

0

Percent

100

80

0

20

40

60

80

100

Magnesium

0

20

40

60

80

100

0

0

20

40

60

80

0

Sodium plus potassium

80

60

40

100

Sulfate plus chloride

60

80

100

Calcium plus magnesium

100

80

60

40

20

100

F. Permian aquifers

20

40

Figure 12. Piper trilinear plots of 

indicating major ion composition of 

groundwater samples from the West 

Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 

1993–2008: A, Quaternary aquifers; B, 

Cambrian, Ordovician, and Silurian 

aquifers; C, Devonian aquifers; D, 

Mississippian aquifers; E, Pennsylvanian 

aquifers; and F, Permian aquifers.

—Continued
Groundwater Quality In West Virginia 23

Nitrogen

Several species of nitrogen are commonly found in 

groundwater including nitrate, nitrite, ammonia, and organic 

nitrogen. Nitrogen in groundwater can come from percolation 

of fertilizers into aquifers; wastewater discharge, including 

leachate from wastewater-treatment plants and septic tanks; 

and natural sources. In general, nitrogen species occur at relatively low levels in West Virginia groundwater. 

Although many species of nitrogen are commonly found 

in groundwater, an MCL has been established only for nitrate, 

at 10 mg/L as N, and nitrite, at 1 mg/L as N (U.S. Environmental Protection Agency, 2009b). Concentrations less than 

10 and 1 mg/L as N for nitrate and nitrite, respectively, protect 

infants younger than 6 months from potentially lethal methemoglobinemia, also known as “blue baby syndrome.” Nitrate 

was detected in less than 40 percent of the samples and nitrite 

in less than 11 percent of the samples. For all samples, nitrate 

plus nitrite concentrations ranged from less than a method 

reporting level of 0.02 mg/L to 11 mg/L, and the median 

value for nitrate plus nitrite was less than the reporting level. 

Median nitrate plus nitrite concentrations also were less than 

the reporting levels in samples from wells that tap Devonian, 

Mississippian, Pennsylvanian, and Permian aquifers (fig. 13). 

The highest nitrate plus nitrite concentration of 11 mg/L 

(nitrite concentration in this sample was less than 0.01 mg/L), 

the only value to exceed the nitrate MCL, was from a well in 

a Quaternary aquifer; Cambrian aquifers, dominated by limestone rocks, had the highest median value, 3.20 mg/L as N. 

The highest nitrate plus nitrite values were consistently from 

either an alluvium- or limestone-dominated setting. These 

are settings where West Virginia’s agricultural activities are 

concentrated; aquifers have greater transmissivity (Kozar and 

Mathes, 2001); and the potential is great for rapid transport 

of contaminants, such as excess fertilizer, from the surface 

to groundwater.

Analyses were performed for ammonia and total nitrogen concentrations. Concentrations ranged from less than 

a method reporting level of 0.01 mg/L to 2.76 mg/L as N. 

Ammonia was found in concentrations greater than the 

reporting level in 238 samples. Ammonia was the dominant 

nitrogen species found in sandstone, shale, and mixed shalesandstone dominated areas. Ammonia used in the treatment 

of coal-mine drainage is a possible source in these areas. 

Analyses for total nitrogen were performed only on samples 

collected after 2004. Total nitrogen concentrations ranged 

from less than 0.06 mg/L to 7.48 mg/L. A qualitative review 

of the data indicates that nitrate accounts for most of the total 

nitrogen in limestone-dominated areas, whereas ammonia 

accounts for most of the total nitrogen in sandstone- and 

shale-dominated areas. This may reflect the different sources 

of nitrogen in these areas.

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Nitrate and nitrite, filtered, in milligrams per liter

11 9 8 41 45 142 19 49

Geologic age

10-3

10-2

10-1

100

101

102

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency maximum contaminant 

level

Individual value

Figure 13. Distribution of nitrate and nitrite concentrations in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) maximum contaminant 

level of 10 milligrams per liter for finished drinking water is shown.
24 Groundwater Quality in West Virginia, 1993–2008

Phosphorus

Phosphorus, the other major nutrient measured as part 

of this study, was commonly detected both as total phosphorus, analyses for which were performed on all samples, 

and orthophosphate, analyses for which were performed 

only on samples collected from 2005 through 2008. Most 

values, 90 percent, for total phosphorus and orthophosphate 

were less than 0.15 and 0.085 mg/L, respectively. No MCLs, 

SMCLs, or HBSLs have been established for total phosphorus 

or orthophosphate.

Concentrations of total phosphorus and orthophosphate 

were highest in areas dominated by mixed shale–sandstone 

rocks. Total phosphorus concentrations in areas dominated by 

either sandstone or shale rocks were similar to those in areas 

of mixed shale–sandstone rocks. However, orthophosphate 

concentrations were lower in both sandstone- and shaledominated areas than in the mixed shale–sandstone areas. The 

lowest median values for total phosphorus and orthophosphate 

were for samples from limestone-dominated areas, 0.01 mg/L 

and 0.006 mg/L, respectively. 

Fecal-Indicator Bacteria

Fecal-indicator bacteria occur naturally in the intestines 

of warm-blooded animals, including humans, and are excreted 

in feces. Although fecal-indicator bacteria rarely cause illness 

themselves, their presence in groundwater indicates the possible presence of pathogens associated with fecal contamination from sewage, agricultural activities, or other sources. 

The preferred fecal-indicator bacteria analyses have changed 

over time, as simpler more accurate tests have been developed 

for indicator bacteria that have strong correlations with the 

occurrence of illness. Over the course of this study, several 

indicator bacteria and methods of analysis have been used. 

Fecal coliform bacteria, identified and enumerated using the 

fecal coliform membrane filtration method (M-FC), have been 

analyzed for throughout the duration of this study (American 

Public Health Association and others, 2005b). Various tests 

for Escherichia coli (E. coli), a species of gut bacteria with a 

strong correlation to illness following consumption or contact 

with contaminated water, have been used during this study. 

Beginning in 2006, the Colilert© defined substrate method was 

used to determine concentrations of E. coli in water samples 

(American Public Health Association and others, 2005a). 

 The USEPA MCL (U.S. Environmental Protection 

Agency, 2009b) stipulates that a positive result for either 

fecal coliform or E. coli in a routine sample triggers a repeat 

sample. A violation of the MCL occurs if the repeat sample is 

also positive. Although repeat samples were not collected from 

any site in this study, a positive result from the single sample 

collected was a presumptive indication of contamination by 

fecal matter. 

Fecal matter and fecal indicator bacteria can be introduced to wells by percolation of nearby surface sources, surface runoff flowing into inadequately cased or grouted wells, 

or failure of subsurface sewage lines and septic tanks. Fecal 

coliform bacteria were detected in 32 of 320 wells sampled 

from 1993 to 2008; E. coli were detected in 8 of 90 samples 

analyzed using the Colilert© method (American Public Health 

Association and others, 2005) from 2006 to 2008. No strong 

spatial patterns were observed in the occurrence of fecal 

coliform bacteria or E. coli (fig. 14). However, samples from 

springs, which are particularly susceptible to contamination 

from surface activities, frequently had quantifiable concentrations of fecal coliform bacteria. Fecal coliform bacteria were 

detected in 67 percent of spring samples (6 of 9), whereas 

fecal coliform bacteria were detected in approximately 8 percent of well samples.

Trace Elements

Trace elements typically occur in natural waters in 

concentrations less than 1.0 mg/L (Hem, 1985). Although 

these elements occur at low concentrations, they may have 

adverse health effects or unpleasant aesthetic effects, such as 

a displeasing taste or odor of drinking water, staining of teeth 

or skin, or staining of plumbing fixtures or laundry. Of the 15 

trace elements that were analyzed for in samples (table 5), the 

USEPA has developed primary MCLs for 10 trace elements 

and SMCLs for another 4 trace elements (U.S. Environmental 

Protection Agency, 2009b). Additionally, HBSLs have been 

developed for manganese, nickel, and zinc (Toccalino and 

others, 2008). 

In samples collected as part of this study, antimony, 

beryllium, cadmium, chromium, mercury, and selenium were 

rarely detected and when detected did not exceed any drinking-water criteria. Thallium was not detected in any sample. 

Arsenic, aluminum, barium, iron, manganese, lead, nickel, 

and zinc were routinely detected in samples, and all but nickel 

exceeded a drinking-water criterion. 

Arsenic

Arsenic, a metalloid element, when consumed in drinking water can cause bladder, lung, and skin cancers and can 

also be responsible for neurological and cardiovascular effects 

(National Research Council, 2001; World Health Organization, 2006). In 2006, the MCL for total arsenic was lowered 

from 50 μg/L to 10 μg/L (Federal Register, 2001). Arsenic 

concentrations ranged from less than a method reporting level 

of 0.2 μg/L in many wells to 138 μg/L in a well completed in 

a Mississippian aquifer in Summers County, West Virginia; 

arsenic was not present in a detectable concentration in more 

than 60 percent of the samples. 

Arsenic concentrations differed by geologic age of aquifers with median concentrations less than the method detection level in Mississippian, Pennsylvanian, and Quaternary 

aquifers. The highest median concentration for any rock type 

was 1.16 μg/L, which was present in a sample from a well in a 

Permian aquifer.
Groundwater Quality In West Virginia 25

40°

38°

82°

78°

80°

40°

38°

82°

78°

80°

EXPLANATION

Fecal coliform bacteria, 

in colony-forming 

units per 100 milliliters

Less than 1

1–250

EXPLANATION

Escherichia coli, in colony-forming 

units per 100 milliliters

Less than 1

1–34

A

B

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Base from West Virginia Department of Environmental Protection, 2005

Figure 14. Distribution of 

groundwater samples from 

the West Virginia ambient 

monitoring network with at 

least one colony-forming unit 

of fecal indicator bacteria 

per 100 milliliters of sample, 

1993–2008: A, Fecal coliform 

and B, Escherichia coli.
26 Groundwater Quality in West Virginia, 1993–2008 Table 5. Statistical summary of metals and trace elements for groundwater samples from West Virginia ambient monitoring network, 1993–2008. [μg/L, microgram per liter; MCL, maximum contaminant level (U.S. Environmental Protection Agency, 2009b); SMCL, secondary maximum contaminant level (U.S. Environmental Protection Agency, 2009b); HBSL, health-based screening level (Toccalino and others, 2008); <, less than; NA, not applicable; --, not reported] Trace element in unfiltered samples Method reporting level Minimum concentration Maximum concentration Median value Criteria MCL SMCL HBSL MCL value Samples exceeding MCL SMCL value Samples exceeding SMCL HBSL value Samples exceeding HBSL Aluminum, recoverable, μg/L <2–4 <2 25,800 3 NA -- 200 17 NA -- Antimony, μg/L <0.1–1 <0.1 5.6 <1 6 0 NA -- NA -- Arsenic, μg/L <0.2–4 <0.2 138 <4 10 15 NA -- NA -- Barium, recoverable, μg/L <0.4–0.6 1.6 7,430 138 2,000 6 NA -- NA -- Beryllium, recoverable, μg/L <0.04–1 <0.04 2 <1 4 0 NA -- NA -- Cadmium, μg/L <0.01–0.5 <0.04 2.4 <0.5 5 0 NA -- NA -- Chromium, recoverable, μg/L <0.04–1 <0.04 30 <1 100 0 NA -- NA -- Iron, recoverable, μg/L <2.0–6.0 <2.0 133,000 427 NA -- 300 169 NA --

Lead, recoverable, μg/L <0.06–2 <0.06 71 <2 15 4 NA -- NA --

Manganese, recoverable, μg/L <0.06–1 <0.06 7,800 94 NA -- 50 183 300 74Mercury, recoverable, μg/L <0.01–0.1 <0.01 0.8 <0.1 2 0 NA -- NA --

Nickel, recoverable, μg/L <0.12–1 <0.12 60 0.1 NA -- NA -- 100 0

Selenium, μg/L <0.08–4 <0.08 7 <4 50 0 NA -- NA --

Thallium, μg/L <0.18–2 <0.18 <2 <2 2 0 NA -- NA --

Zinc, recoverable, μg/L <1–2 <1–2 9,810 6 NA -- 5,000 1 2,000 5
Groundwater Quality In West Virginia 27

Although most arsenic concentrations were less than the 

reporting level, samples from 15 wells exceeded the 10 μg/L 

MCL (fig. 15). Arsenic concentrations exceeding the MCL 

were found in six samples from Pennsylvanian aquifers, four 

from Devonian aquifers, two from Mississippian aquifers, and 

one each from Silurian, Permian, and Quaternary aquifers. 

Aluminum

Aluminum, the third most common crustal element, 

typically occurs in concentrations less than 0.1 mg/L in natural waters (Hem, 1985). Currently there is no health-based 

criterion for aluminum, although there is some concern about 

aluminum neurotoxicity (World Health Organization, 2006). 

A SMCL of 50 to 200 μg/L (U.S. Environmental Protection 

Agency, 2009b) has been established for aluminum for aesthetic effects, primarily discoloration of water. The lower limit 

is a goal concentration for finished water, but the range allows 

regulators to set system-by-system limits. Aluminum concentrations in this study ranged from less than a method reporting 

level of 2 μg/L to 25,800 μg/L with a median value of 3 μg/L. 

Most of the values, 80 percent, ranged from the method reporting level to 88 μg/L.

Aluminum concentrations differed significantly with 

geologic age of the aquifer (Kruskal-Wallis rank sum test 

p-value = 0.0008). Median aluminum values ranged from less 

than the method reporting level of 2 μg/L for samples from 

wells in areas of Cambrian and Quaternary aquifers to 7 μg/L 

for samples from wells in Permian aquifers (fig. 16). 

Concentrations of aluminum exceeded the 50 μg/L 

SMCL goal in 12 percent of samples and the upper SMCL 

limit 200 μg/L in 5 percent of samples. Most of the samples 

with aluminum concentrations exceeding the SMCL were 

from Pennsylvanian aquifers, accounting for 24 of 35 exceedances of the lower limit and 12 of the 17 exceedances of the 

upper limit. Samples exceeding the SMCL were evenly distributed throughout the eastern part of West Virginia (fig. 17). 

40°

38°

82°

78°

80°

EXPLANATION

Total arsenic, in micrograms 

per liter

Not detected

0.2–10

10.1–140

0 30 60 MILES

O

0 30 60 KILOMETERS hio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Base from West Virginia Department of Environmental Protection, 2005

Figure 15. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for total arsenic, 

1993–2008. Samples exceeding the U.S. Environmental Protection Agency (2009b) maximum contaminant level of 10 micrograms 

per liter for finished drinking water are shown in red.
28 Groundwater Quality in West Virginia, 1993–2008 Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

Total aluminum, in micrograms per liter

9 7 8 40 42 128 19 38

Geologic age

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency upper secondary 

maximum contaminant level

U.S. Environmental Protection 

Agency lower secondary 

maximum contaminant level

Individual value

10-1

100

101

102

103

104

105

Figure 16. Distribution of aluminum concentrations in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) secondary 

maximum contaminant levels of 50 and 200 micrograms per liter for finished drinking water are shown.
Groundwater Quality In West Virginia 29

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total aluminum, in 

micrograms per liter

Less than 2.0–50.0

50.1–200

201–26,000

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 17. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for total aluminum, 

1993–2008. Samples exceeding the U.S. Environmental Protection Agency (2009b) secondary maximum contaminant level (SMCL) of 

50 micrograms per liter (μg/L) for finished drinking water are shown in yellow; those exceeding the U.S. Environmental Protection 

Agency (2009b) SMCL of 200 μg/L for finished drinking water are shown in red.
30 Groundwater Quality in West Virginia, 1993–2008

Iron

Iron is the second most abundant metal in the earth’s 

crust but usually occurs in natural waters as a trace element 

(Hem, 1985). A major source of iron in West Virginia’s waters 

is the oxidation of pyrite, a common mineral in Appalachian 

coal-bearing lithologies (Rose and Cravotta, 1998). The 

USEPA has established a SMCL for iron of 300 μg/L (U.S. 

Environmental Protection Agency, 2009b) for aesthetic reasons, primarily the staining of laundry and plumbing fixtures. 

In this study, iron concentrations ranged from less than the 

method reporting level of 2.0 μg/L to 133,000 μg/L with a 

median value of 427 μg/L (table 5). 

Iron concentrations differed significantly with the 

geologic age of aquifers (Kruskal-Wallis rank sum test 

p-value < 0.001) with median values ranging from 14 μg/L 

in samples from Cambrian aquifers to 922 μg/L in samples 

from Pennsylvanian aquifers (fig. 18). Most of the samples, 

57 percent, exceeded the 300 μg/L SMCL, with most 

exceedances in Pennsylvanian aquifers (fig. 19). The proportion of samples exceeding the SMCL stands in marked 

contrast to the 19.1 percent of wells nationally (DeSimone, 

2008). The median iron concentrations in samples from 

Devonian and Pennsylvanian aquifers were greater than the 

SMCL (fig. 18). 

Manganese

Manganese, although a relatively abundant element, 

occurs at approximately one-fiftieth of the crustal abundance 

of iron (Hem, 1985). Manganese commonly occurs at high 

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total iron, in micrograms per liter

11 9 8 41 45 142 19 49

Geologic age

10-1

100

101

102

103

104

106

105

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Individual value

Figure 18. Distribution of iron concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. U.S. Environmental Protection Agency (2009b) secondary maximum 

contaminant level of 300 micrograms per liter for finished drinking water is shown.
Groundwater Quality In West Virginia 31

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total iron, in micrograms 

per liter

Less than 2–300

301–133,000

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 19. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for total iron, 

1993–2008. Samples exceeding the U.S. Environmental Protection Agency (2009b) secondary maximum contaminant level of 

300 micrograms per liter for finished drinking water are shown in red.
32 Groundwater Quality in West Virginia, 1993–2008

concentrations with high iron concentrations because both 

elements are derived from clay minerals in sedimentary rocks 

(Larsen and Mann, 2005). The USEPA has established a manganese SMCL for aesthetic reasons, primarily the staining of 

laundry and plumbing fixtures, of 50 μg/L (U.S. Environmental Protection Agency, 2009b). In addition to the SMCL, there 

is a HBSL of 300 μg/L (Toccalino and others, 2008) based 

on studies indicating increased risk of central nervous system effects (U.S. Environmental Protection Agency, 2009a). 

Manganese concentrations in this study ranged from less than 

the method reporting level of 0.06 μg/L to 7,800 μg/L with a 

median value of 94 μg/L (table 5). Concentrations of most of 

the samples, 80 percent, were between 1 μg/L and 631 μg/L; 

62 percent of the samples exceeded the SMCL, and 25 percent 

exceeded the HBSL.

The lowest median manganese concentration by rock 

type was 1.0 μg/L for samples from wells in Cambrian aquifers (fig. 20). The highest median concentration, 160 μg/L, 

was from wells in Quaternary aquifers. Manganese concentrations differed significantly by geologic age of the aquifer 

(Kruskal-Wallis rank sum test p-value < 0.001). 

Manganese concentrations in most samples, more than 

62 percent, exceeded the 50 μg/L SMCL. More than 25 percent exceeded the HBSL of 300 μg/L (fig. 21). The proportion 

of samples exceeding either the MCL or the HBSL in this 

study is much higher than the proportions that DeSimone 

(2008) found in a nationwide analysis of groundwater from 

domestic wells in which only 21.3 percent exceeded the 

SMCL and 5.22 percent exceeded the HBSL. Although the 

manganese values exceeding the SMCL appear to be distributed somewhat evenly across the study area, SMCL exceedances were more prevalent in water samples from Pennsylvanian aquifers (fig. 21). Additionally, manganese concentrations 

exceeding the HBSL were more frequent in southern West 

Virginia where lower Pennsylvanian aquifers dominate. These 

findings concur with earlier studies that noted higher manganese contaminations in groundwater from Pennsylvanian rocks 

(Mathes and others, 1998; Rose and Cravotta, 1998). 

Lead

Lead has been widely used in plumbing, in paints, and as 

a fuel additive, all uses that have contributed to its widespread 

occurrence in the environment (Hem, 1985). Lead toxicity 

is well established; neurotoxic effects, developmental delays 

in children, and other health effects have led the USEPA to 

establish a public health goal of zero concentration (U.S. Environmental Protection Agency, 2009b). Most of the samples, 

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total manganese, in micrograms per liter

11 9 8 41 45 142 19 49

Geologic age

10-2

10-1

100

101

102

103

105

104

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Health-based screening level

(Toccalino and others, 2008)

Individual value

Figure 20. Distribution of manganese concentrations in groundwater samples from the West Virginia ambient monitoring 

network, grouped by geologic age, 1993–2008. The red line denotes the U.S. Environmental Protection Agency (2009b) secondary 

maximum contaminant level for finished drinking water of 50 micrograms per liter (μg/L); the blue line denotes a health-based 

screening level (Toccalino and others, 2008) of 300 μg/L.
Groundwater Quality In West Virginia 33

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total manganese, 

in micrograms per liter

Less than 0.06–50.0

50.1–300

301–7,800

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 21. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for total manganese, 

1993–2008. Samples exceeding the U.S. Environmental Protection Agency (2009b) secondary maximum contaminant level of 

50 micrograms (μg/L) are in yellow; samples exceeding the health-based screening level (Toccalino and others, 2008) of 300 μg/L 

are in red.
34 Groundwater Quality in West Virginia, 1993–2008

62 percent, had no detectable lead (<0.06 μg/L), and 90 percent of samples had concentrations less than 1.8 μg/L. The 

15 μg/L action level, a concentration requiring use of additional treatment techniques if found in more than 10 percent of 

samples, for lead was exceeded in four samples in concentrations ranging from 17 to 71 μg/L. 

Zinc

Zinc occurs in the Earth’s crust at approximately the 

same abundance as copper and nickel but is more soluble 

than either of those metals (Hem, 1985). Zinc is widely used 

in metallurgy, as a component of brass and bronze, and to 

prevent corrosion through galvanizing. These and other uses 

contribute to the wide distribution of zinc in the environment. 

The use of brass, bronze, and galvanized plumbing fixtures 

can result in zinc entering water-supply systems. The USEPA 

has established a SMCL of 5,000 μg/L for zinc, the threshold 

concentration above which most people can sense a metallic taste due to zinc (U.S. Environmental Protection Agency, 

2009b). In addition to the USEPA SMCL, there is a HBSL of 

2,000 μg/L for zinc (Toccalino and others, 2008); high zinc 

consumption by humans can result in systemic effects, primarily affecting the balance of another essential micronutrient, 

copper (U.S. Environmental Protection Agency, 2005).

Zinc concentrations ranged from less than the method 

reporting level of 1 μg/L to 9,810 μg/L with a median concentration of 6 μg/L (table 5). Concentrations in most of the 

samples, 80 percent, ranged from less than the detection level 

to 89.2 μg/L. Concentrations of zinc did not differ significantly (p = 0.92) with the geologic age of the aquifer (fig. 22). 

Less than 2 percent of samples exceeded established criteria. 

Five samples exceeded the HBSL of 2,000 μg/L, and one 

sample exceeded the 5,000 μg/L SMCL. 

Barium

Barium is a relatively abundant element; the dissolution 

of the common mineral barite is the chief source of barium 

in water (Hem, 1985). High concentrations of barium can 

contribute to high blood pressure, leading the USEPA to 

establish a MCL of 2,000 μg/L (U.S. Environmental Protection Agency, 2009b). Additionally, both the USEPA (2012) 

and the World Health Organization (2006) have established 

criteria at 700 μg/L, the former a drinking-water advisory 

for consumption by a 10-kg child and the latter as a general 

drinking-water guideline. In this survey, barium concentrations ranged from 1.6 μg/L to 7,430 μg/L (table 5); the median 

barium concentration was 138 μg/L. Barium concentrations in 

most of the samples were from 37 μg/L to 732 μg/L. However, 

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total zinc, in micrograms per liter

11 9 8 41 45 142 19 49

Geologic age

10-1

100

101

102

103

105

104

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Health-based screening level

(Toccalino and others, 2008)

Individual value

Figure 22. Distribution of zinc concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. The red line denotes the U.S. Environmental Protection Agency (2009b) 

secondary maximum contaminant level of 5,000 micrograms per liter (μg/L); the blue line denotes a health-based screening level 

(Toccalino and others, 2008) of 2,000 μg/L.
Groundwater Quality In West Virginia 35

six samples, five from Pennsylvanian aquifers and one from a 

Quaternary aquifer, exceeded the 2,000 μg/L MCL (fig. 23). 

Barium concentrations differed significantly among geologicage classes (fig. 24). The lowest median concentrations 

were in samples from Quaternary aquifers, and the highest 

median concentrations were in samples from Permian aquifers 

(Kruskal-Wallis rank sum test p-value < 0.001). 

Radon-222

Radon-222, a radioactive gas that is a decay product of 

uranium, can be given off by groundwater as it exits spigots or showerheads and can accumulate in air to high levels 

in homes; exposure to high levels of radon can increase the 

risk of lung cancer. The USEPA has proposed a two-tiered, 

radon-222 drinking-water regulation, a 300 pCi/L MCL or a 

4,000 pCi/L alternate MCL that will be coupled with a multimedia mitigation program to reduce indoor air radon concentrations (U.S. Environmental Protection Agency, 1999). 

Radon-222 was detected in all but two samples, in 

concentrations ranging from below the reporting limit (10–

30 pCi/L) to 3,330 pCi/L; 45 percent of the samples exceeded 

the proposed MCL (300 pCi/L). The median value for all 

samples was 260 pCi/L; most of the values fell between 40 

and 1,260 pCi/L. Distinct patterns in radon concentrations 

in relation to the geologic age of the aquifer were apparent 

(fig. 25). The median values for Cambrian, Permian, and 

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total barium, in micrograms 

per liter

1.60–2,000

2,010–7,500

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 23. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for total barium, 

1993–2008. Samples exceeding the U.S. Environmental Protection Agency (2009b) maximum contaminant level of 2,000 micrograms 

per liter are in red.
36 Groundwater Quality in West Virginia, 1993–2008 Cambrian Ordovician Silurian Devonian Mississippian

Pennsylvanian

Permian

Quaternary

Barium, in micrograms per liter

11 9 8 41 45 142 19 49

Geologic age

100

101

102

103

104

105

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency secondary maximum 

contaminant level

Individual value

Figure 24. Distribution of barium concentrations in groundwater samples from the West Virginia ambient monitoring network, 

grouped by geologic age of the aquifers, 1993–2008. The red line denotes the U.S. Environmental Protection Agency (2009b) 

secondary maximum contaminant level for finished drinking water of 2,000 micrograms per liter. Cambrian Ordovician Silurian Devonian Mississippian Pennsylvanian Permian Quaternary Radon-222, in picocuries per liter

11 9 8 41 45 142 19 49

Geologic age

100

101

102

103

104

EXPLANATION

19 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

U.S. Environmental Protection 

Agency proposed maximum 

contaminant level

U.S. Environmental Protection 

Agency alternate proposed 

maximum contaminant level

Individual value

Figure 25. Distribution of radon-222 in groundwater samples from the West Virginia ambient monitoring network, grouped 

by geologic age, 1993–2008. The solid red line denotes the proposed U.S. Environmental Protection Agency (1999) maximum 

contaminant level of 300 picocuries per liter (pCi/L); the broken red line indicates the alternate proposed maximum contaminant

level of 4,000 pCi/L with multimedia mitigation program.
Groundwater Quality In West Virginia 37

Quaternary aquifers exceeded the 300 pCi/L MCL. Although 

median radon concentrations for wells in Devonian, Mississippian, and Pennsylvanian aquifers were less than the 300 pCi/L 

MCL, radon concentrations greater than the MCL were 

measured in samples from aquifers of all geologic-age classes 

(fig. 26).

The highest radon-222 concentration detected 

(3,330 pCi/L) was in a sample from a Cambrian aquifer in the 

Blue Ridge Physiographic Province in the extreme eastern 

edge of the Eastern Panhandle, an environmental setting for 

which sparse data on the occurrence and distribution of radon 

are available. The radon-222 concentration for the only other 

sample from that area was 690 pCi/L. These high concentrations and high concentrations documented by investigations 

in other parts of the Blue Ridge (Kozar and others, 2001) 

indicate that further sampling is needed to determine whether 

residents of this area are more likely to encounter groundwater 

with radon concentrations in excess of the proposed alternate 

maximum contaminant level of 4,000 pCi/L and might benefit 

from testing of indoor air and well water for radon-222. 

40°

38°

82°

78°

80°

EXPLANATION

Geologic age (Cardwell 

and others, 1968)

Cambrian

Ordovician

Silurian

Devonian

Mississippian

Pennsylvanian

Permian

Quaternary

Total radon-222, 

in picocuries per liter

Less than 10–300

301–3,350

0 30 60 MILES

0 30 60 KILOMETERS

Ohio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Appalachian Plateaus

Valley and Ridge

Blue Ridge

Physiographic provinces of West Virginia

Figure 26. Distribution of groundwater samples from the West Virginia ambient monitoring network analyzed for radon-222, 

1993–2008. Samples exceeding the proposed U.S. Environmental Protection Agency (1999) maximum contaminant level of 

300 picocuries per liter are in red.
38 Groundwater Quality in West Virginia, 1993–2008

Organic Compounds

The wide use of anthropogenic organic compounds in 

transportation, industrial processes, agriculture, and household 

products has provided multiple routes for these compounds 

to enter the environment. Organic compounds were grouped 

in three classes— two based on physical properties (volatile and semi-volatile organic compounds) and one based on 

use (pesticides). Volatile organic compounds (VOCs) typically have low vapor pressure and, in open systems, quickly 

disperse to the atmosphere. VOCs include solvents, fuel and 

fuel additives, and compounds used in industrial processes and 

chemical manufacturing (Zogorski and others, 2006). Semivolatile organic compounds, as the name implies, have lower 

volatilities and disperse to the atmosphere more slowly than 

VOCs. This group also includes various solvents, compounds 

used in industrial processes, and compounds that result from 

industrial processes, as well as polycyclic aromatic hydrocarbons (PAHs). PAHs are present in coal and oil but are also the 

result of combustion. The third class discussed, pesticides, are 

compounds used to kill unwanted organisms—plants, insects, 

or rodents, for example.

Volatile Organic Compounds

Of the 34 VOCs analyzed for, 25 were detected in at 

least one sample (table 6). In nearly 60 percent of samples in 

which VOCs were detected, only one compound was found. 

The number of VOCs found in the remaining 40 percent of 

samples ranged from two to nine. The two most frequently 

detected VOCs were trichloromethane, more commonly 

known as chloroform, and MTBE, an oxygenate added to 

gasoline to improve combustion efficiency. These compounds 

were also the two most frequently detected in a nationwide 

study of VOCs in groundwater (Zogorski and others, 2006). 

The USEPA has established drinking-water criteria for 

12 of the 25 VOCs detected. Only two VOCs, benzene and 

vinyl chloride, were detected in concentrations exceeding their 

MCLs, 5 and 2 μg/L, respectively (U.S. Environmental Protection Agency, 2009b). Concentrations of benzene, a known 

carcinogen used as a gasoline additive and industrial solvent, 

exceeded the MCL of 5 μg/L (U.S. Environmental Protection 

Agency, 2009b) in two samples, at 9.39 μg/L and 6.38 μg/L. 

Vinyl chloride, a precursor compound in plastics manufacturing and a component of polyvinyl chloride pipe, was found 

to exceed the MCL in one sample with a concentration of 

8.8 μg/L.

The distribution of VOCs in groundwater is largely the 

result of two factors—source and susceptibility. The number 

of VOCs detected in a sample was highest in alluvial and limestone settings (fig. 27), settings that are particularly susceptible 

to rapid transport of contaminants to groundwater (McCoy 

and Kozar, 2007). Proximity to a source of VOCs also figures 

Table 6. Volatile organic compounds analyzed for in 

groundwater samples from West Virginia ambient monitoring 

network, 1993–2008.

[Compounds detected in at least one sample are in bold.]

Constituent

Method 

reporting level, 

in micrograms 

per liter

Number of 

detections

Benzene 0.1 3

Chlorobenzene 0.1 3

Ethylbenzene 0.1 1

1,3-Dichlorobenzene 0.1 0

1,2-Dichlorobenzene 0.1 0

1,4-Dichlorobenzene 0.1 1

Bromoform 0.2 4

Tetrachloromethane 0.2 1

Chloroform 0.1 25

1,1,1-Trichloroethane 0.1 7

1,1,2-Trichlorotrifluoroethane 0.1 2

1,2-Dichloroethane 0.2 0

Diethyl ether 0.2 2

Ethyl tert-butyl ether 0.1 0

cis-1,2-Dichloroethylene 0.1 4

Tetrachloroethylene 0.1 5

trans-1,2-Dichloroethylene 0.1 0

Trichloroethylene 0.1 9

1,1-Dichloroethane 0.1 5

Diisopropyl ether 0.2 6

m- and p-Xylene 0.2 3

Bromodichloromethane 0.1 7

Dibromochloromethane 0.2 5

Dichlorodifluoromethane 0.2 0

Trichlorofluoromethane 0.2 0

tert-Butyl methyl ether 0.2 22

Dichloromethane 0.2 0

o-Xylene 0.1 1

1,2-Dichloropropane 0.1 0

Styrene 0.1 1

tert-Pentyl methyl ether 0.2 2

Toluene 0.1 8

Vinyl chloride 0.2 2

1,1-Dichloroethylene 0.1 2
Groundwater Quality In West Virginia 39

in the distribution of VOCs. Several of the sites where VOCs 

were detected were near known sources of VOCs, including 

documented spills, underground gasoline storage tanks, or 

industrial areas.

Semi-Volatile Compounds

The limited set of semi-volatile compound data, 18 samples collected during 2005–08, indicate that these compounds 

infrequently contaminate groundwater in West Virginia. Of the 

57 semi-volatile compounds for which samples were analyzed 

(table 7), only two, phenol and phenanthrene, were detected, 

and those were found at the threshold of detection. Phenol 

concentrations were detected in two wells in an industrialized 

area of the Ohio River alluvial aquifer, and both were estimated values, 0.1 and 0.3 μg/L. The presence of phenanthrene 

was verified in a well at an industrial site, but the concentration was too small to be quantified.

Pesticides

Pesticides were analyzed in 77 selected samples, typically 

from agricultural settings where pesticide use is greatest. Samples were analyzed for a suite of 52 pesticides (table 8), primarily herbicides and insecticides, of which 12 were detected. 

At least one pesticide was detected in 22 of the 77 samples 

for which pesticide analyses were conducted. Drinking-water 

criteria exist for 11 of the 12 detected compounds—2 MCLs 

and 9 HBSLs. Of the pesticides with drinking-water criteria, 

none were detected in concentrations exceeding the criteria. 

The two most commonly detected pesticides were deethylatrazine, a breakdown product of the herbicide atrazine, and 

atrazine itself, which were found in 16 and 15 samples, respectively. Most of the samples, 16 of 22, in which pesticides were 

detected contained detectable concentrations of 2 or more 

pesticides with as many as 7 pesticides or pesticide degradates 

detected in one sample. 

All

Quaternary alluvium

Limestone

Sandstone

Shale

Shale/sandstone

Number of volatile organic compounds detected per sample

276 39 27 123 77 10

Dominant rock type

0

1

2

3

4

5

7

6

8

9

EXPLANATION

77 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Figure 27. Distribution of the number of volatile organic compounds detected per groundwater sample from the West 

Virginia ambient monitoring network, grouped by dominant rock type, 1993–2008.
40 Groundwater Quality in West Virginia, 1993–2008

Table 7. Semi-volatile organic compounds analyzed for in selected groundwater samples from the West Virginia ambient monitoring 

network, 1993–2008.

[Compounds detected in at least one sample are in bold.]

Constituent

Laboratory 

reporting level, 

in micrograms 

per liter

Number of 

detections Constituent

Laboratory 

reporting level, 

in micrograms 

per liter

Number of 

detections

Dibenz[a,h]anthracene 0.42 0 N-Nitrosodiphenylamine 0.28 0

Chrysene 0.33 0 Hexachloroethane 0.24 0

bis(2-chloroisopropyl) ether 0.14 0 Fluoranthene 0.3 0

2,4-Dimethylphenol 0.8 0 1,2-Diphenylhydrazine 0.3 0

4,6-Dinitro-2-methylphenol 0.76 0 Indeno[1,2,3-cd]pyrene 0.38 0

4-Bromophenylphenylether 0.24 0 Isophorone 0.26 0

4-Chlorophenyl phenyl ether 0.34 0 4-Chloro-3-methylphenol 0.55 0

Fluorene 0.33 0 bis(2-Chloroethoxy)methane 0.24 0

Acenaphthene 0.28 0 Naphthalene 0.22 0

Acenaphthylene 0.3 0 2-Chloronaphthalene 0.16 0

Anthracene 0.39 0 Phenanthrene 0.32 1

Benz[a]anthracene 0.26 0 Phenol 0.28 2

1,2,4-Trichlorobenzene 0.26 0 2,4,6-Trichlorophenol 0.34 0

Hexachlorobenzene 0.3 0 2,4-Dichlorophenol 0.36 0

1,3-Dichlorobenzene 0.22 0 2,4-Dinitrophenol 1.4 0

Nitrobenzene 0.26 0 2-Chlorophenol 0.26 0

1,2-Dichlorobenzene 0.2 0 2-Nitrophenol 0.4 0

1,4-Dichlorobenzene 0.22 0 4-Nitrophenol 0.51 0

Benzidine 1,000 0 Pentachlorophenol 0.6 0

3,3’-Dichlorobenzidine 0.42 0 bis(2-Ethylhexyl) phthalate 2 0

Benzo[a]pyrene 0.33 0 Butylbenzyl phthalate 1.8 0

Benzo[b]fluoranthene 0.3 0 Di-n-butyl phthalate 2 0

Benzo[ghi]perylene 0.38 0 Diethyl phthalate 0.61 0

Benzo[k]fluoranthene 0.3 0 Dimethyl phthalate 0.36 0

bis(2-Chloroethyl)ether 0.3 0 Di-n-octyl phthalate 0.6 0

Hexachlorobutadiene 0.24 0 Pyrene 0.35 0

Hexachlorocyclopentadiene 0.5 0 2,4-Dinitrotoluene 0.56 0

N-Nitrosodi-n-propylamine 0.4 0 2,6-Dinitrotoluene 0.4 0

N-Nitrosodimethylamine 0.24 0
Groundwater Quality In West Virginia 41

Table 8. Pesticides and pesticide degradates analyzed for in 77 groundwater samples from the West Virginia ambient monitoring 

network, 1993–2008.

[Compounds detected in at least one sample are in bold. HCH, hexachlorocyclohexane; EPTC, S-ethyl dipropyl(thiocarbamate); DDE, 1,1-bis-

(4-chlorophenyl)-2,2-dichloroethene]

Constituent

Laboratory 

reporting level, 

in micrograms 

per liter

Number of 

detections Constituent

Laboratory 

reporting level, 

in micrograms 

per liter

Number of 

detections

alpha-HCH 0.004 0 Fonofos 0.0044 0

Acetochlor 0.01 0 Lindane 0.004 0

Alachlor 0.008 0 Linuron 0.06 0

2,6-Diethylaniline 0.006 0 Malathion 0.016 0

Atrazine 0.007 15 Parathion-methyl 0.008 0

Azinphos-methyl 0.12 0 Metolachlor 0.014 8

Benfluralin 0.014 0 Metribuzin 0.012 0

Butylate 0.004 0 Molinate 0.0026 0

Carbaryl 0.06 1 Napropamide 0.008 0

Carbofuran 0.06 0 p,p’-DDE 0.002 2

Chlorpyrifos 0.01 0 Parathion 0.02 0

cis-Permethrin 0.014 0 Pebulate 0.016 0

Cyanazine 0.022 0 Pendimethalin 0.012 0

Dacthal 0.0076 1 Phorate 0.02 0

Deethylatrazine 0.014 16 Prometon 0.012 6

Diazinon 0.005 1 Propyzamide 0.0036 0

Dieldrin 0.009 3 Propachlor 0.006 0

Disulfoton 0.04 0 Propanil 0.01 0

EPTC 0.002 0 Propargite 0.02 0

Ethalfluralin 0.006 0 Simazine 0.006 13

Ethoprophos 0.016 0 Tebuthiuron 0.028 3

Desulfinylfipronil amide 0.029 0 Terbacil 0.024 3

Fipronil sulfide 0.013 0 Terbufos 0.018 0

Fipronil sulfone 0.024 0 Thiobencarb 0.016 0

Desulfinylfipronil 0.012 0 Tri-allate 0.006 0

Fipronil 0.018 0 Trifluralin 0.018 0
42 Groundwater Quality in West Virginia, 1993–2008

The pesticide results display a spatial pattern of pesticide 

occurrence in groundwater (fig. 28), although the purposeful 

selection of sites in areas of expected pesticide occurrence 

likely influenced the pattern. Groundwater in limestonedominated areas most frequently contained greater numbers of 

pesticides detected (fig. 29). As with the occurrence of VOCs 

in groundwater, groundwater contamination by pesticides is 

a product of source and susceptibility. Agricultural lands in 

West Virginia, where pesticide use is heaviest in the State, 

are concentrated in limestone-dominated areas. These are 

also areas where surface runoff quickly infiltrates to the water 

table. Although many of the wells in the limestone-dominated 

areas were not on agricultural lands, the high transmissivity of 

Karstic limestone aquifers allows for the rapid movement of 

contaminants to nearby areas. This condition of high pesticide 

use in areas where surface-water/groundwater connectivity is 

high makes West Virginia’s limestone-dominated areas especially susceptible to pesticide contamination. 

Relations Among Water-Quality 

Characteristics and Environmental 

Settings

Groundwater quality can be affected by environmental 

settings, including the local geology that affects geochemical 

processes, topography, land cover, and population density. 

Well-construction characteristics, including well depth, casing 

length, casing material, and well grouting, also can affect the 

quality of groundwater samples. PCA was used to evaluate the 

role these factors play in contributing to the water quality of 

the sampled wells. 

Geochemical processes were evaluated by examining elemental loadings computed for the first two principle 

components. The first principal component accounted for 

22 percent of the variance in the data, and the second principal 

40°

38°

82°

78°

80°

EXPLANATION

Number of pesticides 

detected

0

1–2

3–5

6–7

0 30 60 MILES

O

0 30 60 KILOMETERS hio River

Kanawha River

OHIO

VIRGINIA

WEST VIRGINIA

PENNSYLVANIA

KENTUCKY

MARYLAND

Figure 28. Distribution of samples from the West Virginia ambient monitoring network analyzed for pesticides and the number 

of pesticides detected per groundwater sample, 1993–2008.
Implications for Further Studies of West Virginia Groundwater Resources 43

All

Quaternary alluvium

Limestone

Sandstone

Shale

Number of volatile organic compounds detected per sample

77 21 14 20 19

Dominant rock type

0

1

2

3

4

5

7

6

8

EXPLANATION

14 Number of samples

Outlier

90th percentile

75th percentile

Median

25th percentile

10th percentile

Figure 29. Distribution of the number of pesticides detected per groundwater sample from the West Virginia ambient 

monitoring network, grouped by dominant rock type, 1993–2008.

component accounted for an additional 18 percent variance in 

the data set. The first principal component (principal component 1 in table 9) showed strong negative eigenvector loadings 

for calcium, magnesium, potassium, sodium, bicarbonate, 

bromide, chloride, and sulfate, with total dissolved solids, 

indicating these constituents are the primary constituents 

responsible for the variance in total dissolved solids content 

in groundwater from the sampled wells. The second principal component (principal component 2 in table 9) showed 

strong negative eigenvector loadings for calcium, magnesium, 

sulfate, manganese, and zinc and strong positive eigenvector loadings for sodium, chloride, bromide, and bicarbonate, 

indicating cation exchange processes occurred at boundaries 

between shallow calcium/magnesium water types and deeper 

sodium/chloride type waters. 

No statistically significant relation between groundwater 

quality and well depth or groundwater quality and topographic 

setting (hilltop, hillside, or valley) was discerned in this analysis, although such relations were reported in an earlier analysis 

of domestic wells in West Virginia (Mathes and others, 

1998). The absence of relations among groundwater quality, 

well depth, or topographic setting in this present analysis is 

likely attributable primarily to sampling public-supply wells, 

whereas Mathes and others (1998) sampled domestic wells. 

Public-supply wells are typically pumped at higher rates and 

for much longer periods than domestic wells, which can result 

in cones of depression in the water table that contribute to 

differences in the origin of pumped water. Public-supply wells 

are more likely to receive ground-water recharge from a much 

broader area than domestic wells. Lastly, the population of 

hilltop wells is very small, 29 of 324. These differences tend to 

mask the effects of topography and well depth in public-supply wells, although the effects of these settings were readily 

apparent in domestic wells in the earlier study by Mathes and 

others (1998). 

Implications for Further Studies of 

West Virginia Groundwater Resources

Although this report presents the most comprehensive 

statewide analysis of groundwater quality to date, many 

questions remain to be answered. The ambient groundwater 
44 Groundwater Quality in West Virginia, 1993–2008

Table 9. Principal components analysis showing distribution 

of eigenvector loadings for the first two principal components 

for samples from the West Virginia ambient monitoring network, 

1993–2008.

[mg/L, milligram per liter; μg/L, microgram per liter; N, nitrogen; pCi/L, 

picocuries per liter; nsr, indicates that the eigenvector loading computed was 

small and not statistically significant (p>0.05) to the analysis]

Constituent Component 1 Component 2

Dissolved oxygen, mg/L 0.154 -0.158

Calcium, mg/L -0.315 -0.334

Magnesium, mg/L -0.308 -0.369

Potassium, mg/L -0.243 nsr

Sodium, mg/L -0.284 0.375

Bicarbonate, mg/L -0.309 0.208

Bromide, mg/L -0.256 0.348

Chloride, mg/L -0.264 0.354

Sulfate, mg/L -0.341 -0.333

Total dissolved solids (residue 

on evaporation), mg/L

-0.472 nsr

Aluminum, μg/L nsr nsr

Arsenic, μg/L nsr nsr

Barium, μg/L 0.177 -0.112

Iron, μg/L nsr nsr

Manganese, μg/L -0.123 -0.241

Zinc, μg/L -0.171 -0.241

Radon, pCi/L nsr nsr

Phosphorous, mg/L nsr nsr

Nitrate + nitrite, mg/L as N nsr nsr

program was designed to provide a broad assessment of the 

quality of West Virginia’s groundwater. This goal has been 

achieved. However, to gain a more complete understanding 

of the resource and the factors affecting groundwater quality, 

further sampling and studies are needed. Sampling and studies 

that would provide greater sample density in settings underrepresented in this data set, such as the Permian aquifers of 

northwest West Virginia, and measurement of more constituents, such as broader suites of pesticides and other organic 

contaminants in susceptible areas, would advance the understanding of groundwater quality in West Virginia. Sampling 

and studies to address unanswered or new questions could be 

designed in such a way as to specifically answer those questions while eliminating environmental noise or confounding 

influences. It is likely that variability due to factors other than 

geochemical processes or environmental setting masked many 

patterns in the data. Selection of sites more closely matched in 

well construction, withdrawal rates, and pump type also would 

likely reduce confounding variability.

A refocused sampling effort could clarify some unresolved patterns seen in this analysis, provide information 

on under-represented areas and settings, or address new 

questions. Further investigation of geochemical controls on 

manganese, arsenic, or radon-222 with a study design tailored 

to these questions would likely increase the understanding 

of the occurrence and distribution of these constituents in 

groundwater. For example, the collection of samples in areas 

with known elevated arsenic concentrations and analysis of 

the samples for the various arsenic species, with the collection 

of appropriate supporting data, would allow for the development of models of arsenic risk from groundwater. Collection 

of data in areas of lower population density, which are areas 

served by few public-supply wells such as the areas of Permian geology in northwest West Virginia, and, therefore, are 

sampled less densely, would increase the overall resolution, 

potentially revealing patterns not seen with current samples. 

The examination of issues that have yet to be studied or have 

only recently emerged would provide information not attainable from the current data set. Issues that could be addressed 

include the effect of injection wells on groundwater quality, 

the occurrence and distribution of industrial compounds in 

alluvial aquifers, and the effect of urbanization on groundwater resources.

The aforementioned studies do not include a temporal 

component on a scale relevant to groundwater. The original network of 26 annually sampled wells was designed, in 

part, as a trend-detection network. However, a 1-year period 

between samples is a relatively brief interval for changes in 

groundwater systems. A network of wells, sampled at a greater 

interval, can provide consistent data over time. A network of 

wells, each selected to represent an important environmental 

setting and sampled at an appropriate temporal scale, would be 

sufficient to detect broad trends and possibly predict threats to 

West Virginia’s groundwater resources.

Summary and Conclusions

The variability in the quality of West Virginia’s groundwater resources is most strongly affected by geology. Iron in 

Pennsylvanian bedrock aquifers, the presence of pesticides 

in limestone-dominated areas, and industrial compounds in 

Quaternary alluvial aquifers can all be attributed to geologic 

characteristics, either when the rock acts a as source of the 

water-quality constituent or when geologic characteristics 

contribute to aquifer susceptibility to contamination. Although 

geology exerts the strongest influence on groundwater quality, anthropogenic influences also were noted, primarily the 

presence of synthetic organic compounds, such as pesticides, 

and excess nutrients from agricultural activities. Knowledge 

of these patterns in groundwater quality can be of use to the 

approximately 42 percent of West Virginians that rely on 

groundwater for drinking water.

The 324 wells and springs sampled for this study were 

from a wide variety of environmental settings; samples were 

from both unconsolidated alluvial aquifers and consolidated 
References Cited 45

bedrock aquifers. The consolidated bedrock aquifers sampled 

ranged in age from Cambrian to Permian. The proportion of 

samples collected from each setting was not even. The density 

of sampling was highest in Quaternary alluvial aquifers and 

Cambrian bedrock aquifers and lowest in Permian bedrock 

aquifers. Sampling density within an environmental setting 

was largely a function of population density, which in turn 

determines well density.

Although this study, conducted by the U.S. Geological 

Survey in cooperation with the West Virginia Department 

of Environmental Protection, Division of Water and Waste 

Management, did not attempt to evaluate finished drinkingwater quality, drinking-water-quality criteria were used as 

benchmarks against which to compare samples. These criteria 

are not applicable to the raw-water samples analyzed in this 

study and are for illustrative purposes only. However, many 

West Virginians rely on groundwater as a drinking supply, and wells in certain environmental settings may produce water with concentrations of constituents that exceed 

drinking-water thresholds. 

Most samples contained constituent concentrations less 

than the maximum contaminant levels (MCLs). However, 

some samples exceeded non-enforceable secondary maximum 

contaminant levels (SMCLs), proposed MCLs, or advisory 

health-based screening levels (HBSLs). Radon-222 concentrations exceeded the proposed MCL of 300 picocuries per 

liter (pCi/L) in 45 percent of samples, and iron concentrations exceeded the SMCL of 300 micrograms per liter (μg/L) 

in 57 percent of samples. Manganese concentrations were 

greater than the SMCL (50 μg/L) in 62 percent of samples and 

were greater than the HBSL (300 μg/L) in 25 percent of the 

samples. Other sampled constituents, including organic compounds and trace elements, exceeded drinking-water criteria at 

much lower frequencies.

The radon-222 median values in samples from Cambrian, Ordovician, Silurian, Permian, and Quaternary aquifers 

exceeded the proposed 300-pCi/L MCL. Although median 

radon concentrations for wells in Devonian, Mississippian, 

and Pennsylvanian aquifers were less than the proposed MCL, 

radon concentrations greater than the proposed MCL were 

measured in samples from aquifers of all geologic ages.

The median iron concentrations for samples from 

Devonian and Pennsylvanian aquifers were greater than the 

300 μg/L SMCL. Iron concentrations exceeded the SMCL 

in aquifers of all geologic ages, except Cambrian. Median 

concentrations of manganese exceeded the SMCL in samples 

from Devonian, Pennsylvanian, and Quaternary aquifers. As 

with iron, manganese concentrations were found to exceed 

the SMCL in at least one sample from aquifers of all geologic 

ages, except Cambrian. 

The distribution of organic compounds in groundwater 

is largely the result of two factors—source, such as industrial activity or agriculture, and susceptibility, such as highly 

transmissive limestone and alluvial settings. Volatile organic 

compounds (VOCs) were detected with greater frequency 

in areas dominated by either limestone or alluvium. Alluvial 

settings, in addition to being highly transmissive, are where 

the majority of West Virginia’s industrial activities are located. 

Pesticides were detected most frequently and in higher 

concentrations in limestone-dominated areas. Most of West 

Virginia’s agriculture is concentrated in those areas. 

This study is one of the most comprehensive assessments 

of the water quality of West Virginia’s groundwater resources 

to date. Analysis of these samples from wells and springs 

across West Virginia provides documentation of relations 

among groundwater quality and the environmental setting of 

the wells and springs. This analysis has also identified opportunities to further refine the understanding of groundwater 

quality in West Virginia, potentially improving the management and protection of this valuable source of drinking water.

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Prepared by the West Trenton Publishing Service Center

For more information, write to:

West Virginia Water Science Center

U.S. Geological Survey

11 Dunbar Street

Charleston, WV 25301

http://wv.usgs.gov/
Chambers and others—Groundwater Quality in West Virginia, 1993–2008—Scientific Investigations Report 2012–5186