U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5129

In cooperation with the Pike County Conservation District

Groundwater-Quality Assessment,

Pike County, Pennsylvania, 2007 
Cover.

Typical well completed in bedrock in Pike County. Photograph by Arthur Lilienthal, U.S. Geological Survey. 
Groundwater-Quality Assessment,

Pike County, Pennsylvania, 2007

By Lisa A. Senior

In cooperation with the Pike County Conservation District

Scientific Investigations Report 2009–5129

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2009

For product and ordering information:

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

Telephone: 1-888-ASK-USGS

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

natural hazards, and the environment:

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

Telephone: 1-888-ASK-USGS

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

U.S. Government.

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

reproduce any copyrighted materials contained within this report.

Suggested citation:

Senior, L.A., 2009, Groundwater-quality assessment, Pike County, Pennsylvania, 2007: U.S. Geological Survey

Scientific Investigations Report 2009-5129, 53 p.
iii

Contents

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

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

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

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

Hydrogeologic Setting ................................................................................................................3

Land Use........................................................................................................................................3

Previous Investigations........................................................................................................................6

Study Methods ...............................................................................................................................................6

Selection of Sampling Locations........................................................................................................6

Collection of Samples ..........................................................................................................................6

Analysis of Samples .............................................................................................................................8

Groundwater-Quality Assessment..............................................................................................................8

Inorganic Constituents.........................................................................................................................9

General Water Quality.................................................................................................................9

Major Ions.....................................................................................................................................9

Nitrate and Other Nutrients .....................................................................................................12

Trace Elements and Metals......................................................................................................13

Relation Between Dissolved and Total Major Ions and Metals................................14

Organic Compounds...........................................................................................................................19

Volatile Organic Compounds....................................................................................................19

Wastewater Compounds ..........................................................................................................19

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

Radon-222....................................................................................................................................20

Gross Alpha-Particle and Gross Beta-Particle Activity ......................................................20

Uranium .......................................................................................................................................22

Relation Between Groundwater Quality and Setting....................................................................22

Groundwater Quality and Geology..........................................................................................22

Groundwater Quality and Land Use........................................................................................24

Relation Between Groundwater Quality and Surface-Water Quality ........................................28

Temporal Aspects of Groundwater Quality ....................................................................................28

Age of Groundwater..................................................................................................................28

Change in Groundwater Quality through Time......................................................................29

Summary and Conclusions.........................................................................................................................31

Acknowledgments.......................................................................................................................................33

References Cited..........................................................................................................................................33
iv

Figures

1–2. Maps showing:

1. Geology of Pike County, Pa., showing bedrock geologic unit and extent of the

glacial aquifer near the Delaware River and locations of 20 wells sampled by

the U.S. Geological Survey in 2007 ..................................................................................4

2. Land use in Pike County, Pa., in 2005 and locations of 20 wells sampled in

2007 and selected stream water-quality monitoring sites............................................5

3–11. Graphs showing:

3. (A) Acid-neutralizing capacity and (B) specific conductance in relation

to pH in groundwater samples collected from 20 wells in Pike

County, Pa., in 2007 ............................................................................................................11

4. Chloride and boron concentrations in relation to sodium concentrations in 

groundwater samples collected from 20 wells in Pike County, Pa., in 2007 ............12

5. Concentrations of (A) dissolved iron and (B) dissolved manganese

in relation to dissolved oxygen concentrations in groundwater samples

collected from 20 wells in Pike County, Pa., in 2007.....................................................15

6. Concentrations of (A) dissolved copper and (B) dissolved zinc in relation

to pH in groundwater samples collected from 20 wells in Pike

County, Pa., in 2007 ............................................................................................................16

7. Dissolved and total concentrations of iron, in order of increasing total iron

concentrations, in groundwater samples collected from six wells in

Pike County, Pa., in 2007 ...................................................................................................18

8. Total arsenic and lead concentrations in relation to total iron concentrations

in groundwater samples collected from six wells in Pike County, Pa., in 2007.......18

9. Radon-222 activities in groundwater samples from 20 wells in different

geologic units, Pike County, Pa., 2007 ............................................................................23

10. Concentrations of (A) chloride and (B) nitrite plus nitrate as nitrogen in 

groundwater samples from 20 wells in different land-use areas, Pike

County, Pa., 2007 ................................................................................................................25

11. Concentrations of (A) chloride and (B) nitrite plus nitrate as nitrogen

in groundwater from five wells sampled at time intervals ranging from 6 to 25

years in the period from 1982 to 2007, Pike County, Pa. .............................................30
v

Tables

1. Geologic unit and land use for 20 wells sampled in Pike County, Pa., during the

2007 assessment...........................................................................................................................7

2. Annual average concentrations of selected constituents in precipitation at

Milford, Pa., 2006...........................................................................................................................9

3. Minimum, median, and maximum values for well characteristics, field

measurements, and concentrations of dissolved major ions and nutrients in

groundwater samples collected from 20 wells in Pike County, Pa., in 2007 .....................10

4. Minimum, median, and maximum values for concentrations of dissolved metals

in groundwater samples collected from 20 wells and concentrations of

dissolved and total metals in groundwater from 6 of the 20 wells in Pike 

County, Pa., in 2007 .....................................................................................................................13

5. Concentrations of major ions, iron, and manganese in filtered and unfiltered

samples from well PI-308 collected August 30 and September 9, 2007,

respectively, in Pike County, Pa. ..............................................................................................17

6. Detected dissolved organic compounds in groundwater samples collected

from 20 wells in Pike County, Pa., in 2007 ...............................................................................19

7. Minimum, median, and maximum values for activities of dissolved radionuclides

and uranium concentrations in groundwater samples collected from 20 wells

in Pike County, Pa., in 2007 ........................................................................................................21

8. Detected organic wastewater and volatile organic compounds and

concentrations of inorganic and nutrient wastewater indicators in groundwater 

samples collected from 20 wells in Pike County, Pa., in 2007..............................................26

9. Estimated apparent ages in years before 2007 for groundwater samples from

four wells in Pike County, Pa., in 2007 .....................................................................................29

10. Construction characteristics and location of 20 wells sampled in 2007 in Pike

County, Pa. ...................................................................................................................................35

11. Field measurements and results of laboratory analyses for concentrations of

major ions, nutrients, and selected metals and trace elements in groundwater

samples from 20 wells in Pike County, Pa., 1982–2007 .........................................................36

12. Results of laboratory analysis for volatile organic compounds in groundwater

samples from 20 wells in Pike County, Pa., 2001 and 2007...................................................41

13. Results of laboratory analysis for organic wastewater compounds in water

samples from 20 wells in Pike County, Pa., 2001 and 2007...................................................45

14. Results of laboratory analysis for radionuclide activities in water from 20 wells in

Pike County, Pa., 2001 and 2007................................................................................................52

15. Dissolved gas data used to calculate excess air and recharge temperature for

CFC and SF6 age-dating and measured concentrations of CFC and SF6 gases in

groundwater samples collected from four wells in Pike County, Pa., in 2007..................53
vi

Conversion Factors and Datums

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

Area

acre 4,047 square meter (m2)

acre 0.4047 hectare (ha)

acre 0.4047 square hectometer (hm2)

acre 0.004047 square kilometer (km2)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2)

Volume

gallon (gal) 3.785 liter (L)

gallon (gal) 0.003785 cubic meter (m3)

gallon (gal) 3.785 cubic decimeter (dm3)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

cubic foot per second per square

mile [(ft3/s)/mi2]

0.01093 cubic meter per second per square

kilometer [(m3/s)/km2]

gallon per minute (gal/min) 0.06309 liter per second (L/s)

Radioactivity

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

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

°F=(1.8×°C)+32

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.

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).
Abstract

Pike County, a 545 square-mile area in northeastern 

Pennsylvania, has experienced the largest relative population 

growth of any county in the state from 1990 to 2000 and its 

population is projected to grow substantially through 2025. 

This growing population may result in added dependence and 

stresses on water resources, including the potential to reduce 

the quantity and degrade the quality of groundwater and 

associated stream base flow with changing land use. Groundwater is the main source of drinking water in the county and 

is derived primarily from fractured-rock aquifers (shales, 

siltstones, and sandstones) and some unconsolidated glacial 

deposits that are recharged locally from precipitation. The 

principal land uses in the county as of 2005 were public, residential, agricultural, hunt club/private recreational, roads, and 

commercial. The public lands cover a third of the county and 

include national park, state park, and other state lands, much 

of which are forested. Individual on-site wells and wastewater 

disposal are common in many residential areas.

In 2007, the U.S. Geological Survey, in cooperation 

with the Pike County Conservation District, began a study to 

provide current information on groundwater quality throughout the county that will be helpful for water-resource planning. 

The countywide reconnaissance assessment of groundwater 

quality documents current conditions with existing land uses 

and may serve as a baseline of groundwater quality for future 

comparison.

Twenty wells were sampled in 2007 throughout Pike 

County to represent groundwater quality in the principal land 

uses (commercial, high-density and moderate-density residential with on-site wastewater disposal, residential in a sewered 

area, pre-development, and undeveloped) and geologic units 

(five fractured-rock aquifers and one glacial unconsolidated 

aquifer). Analyses selected for the groundwater samples were 

intended to identify naturally occurring constituents from the 

aquifer or constituents introduced by human activities that 

pose a health risk or otherwise were of concern in groundwater in the county. The analyses included major ions, nutrients, 

selected trace metals, volatile organic compounds (VOCs), 

selected organic wastewater compounds, gross alpha-particle 

and gross beta-particle activity, uranium, and radon-222. 

Analyses of the 20 samples were primarily for dissolved constituents, but six samples were analyzed for both dissolved and 

total metals.

Results of the 2007 sampling indicated few water-quality 

problems, although concentrations of some constituents 

indicated influence of human activities on groundwater. No 

constituent analyzed exceeded any primary drinking-water 

standard or maximum contaminant level (MCL) established 

by the U.S. Environmental Protection Agency. Radon-222 

levels were greater than, or equal to, the proposed MCL of 

300 picocuries per liter (pCi/L) in water from 15 (75 percent) 

of the 20 wells. Radon-222 levels did not exceed the alternative MCL of 4,000 pCi/L in any groundwater sample. Radon222 is naturally occurring, and the greatest concentrations (up 

to 2,650 pCi/L) were in water samples from wells in members 

of the Catskill Formation, a fractured-rock aquifer. The dissolved arsenic concentration of 3.9 micrograms per liter (μg/L) 

in one sample was greater than the health-advisory (HA) level 

of 2 μg/L but less than the MCL of 10 μg/L. Recommended 

or secondary maximum contaminant levels (SMCLs) were 

exceeded for pH, dissolved iron, and dissolved manganese.

In six samples analyzed for dissolved and total concentrations of selected metals, total concentrations commonly were 

much greater than dissolved concentrations of iron, and to a 

lesser degree, for arsenic, lead, copper, and manganese. Concentrations of iron above the SMCL of 300 μg/L may be more 

widespread in the county for particulate iron than for dissolved 

iron. The total arsenic concentration in one of the six samples 

was greater than the HA level of 2 μg/L but less than the MCL 

of 10 μg/L. The total manganese concentration of 361 μg/L in 

one sample exceeded the HA of 300 μg/L for manganese in 

drinking water.

Chloride concentrations were above the estimated natural 

background levels of 1 to 5 mg/L in about half of the wells, 

indicating that human activities may have influenced groundwater quality. Nitrate concentrations were less than the estimated natural background level of less than 0.8 mg/L as N in 

all but two groundwater samples. Boron concentrations equal 

to or greater than 20 mg/L are above natural background levels 

and were measured in wells with elevated sodium and chloride 

levels, indicating probable association with septic effluent and 

(or) road salt linked to residential development.

Groundwater-Quality Assessment, Pike County, 

Pennsylvania, 2007

By Lisa A. Senior
2 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Anthropogenic organic compounds were detected at low 

or trace levels in groundwater from 10 of the 20 wells, indicating human activities at the land surface have affected groundwater quality to some degree. These compounds included 

VOCs in 3 groundwater samples and a few organic wastewater 

compounds in 10 groundwater samples. The highest VOC concentration measured was 39 μg/L of Freon-11 and indicated 

local groundwater contamination by improper disposal of the 

compound. DEET (N,N-diethyl-meta-toluamide), an insect 

repellent, was the most frequently detected organic wastewater 

compound.

Concentrations of chloride and nitrite plus nitrate as 

nitrogen generally were greater in water from wells in the 

commercial and residential areas with on-site wastewater 

disposal than in undeveloped and sewered areas. The anthropogenic compound DEET was detected in water from wells 

in most land-use areas, including undeveloped. Most other 

organic wastewater compounds and VOCs, except for the one 

well sample with Freon-11 contamination, were detected in 

water from wells in commercial and residential areas with onsite wastewater disposal.

Age-dating by measurement of chlorofluorocarbons 

(CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6) 

in groundwater in samples from three wells yielded a range 

of ages from 6 to 54 years before 2007, with younger water 

in the glacial aquifer and older water in the bedrock aquifer. 

These findings indicate that groundwater in both aquifer types 

probably is susceptible to contamination by human activities 

at or near the land surface. Comparison of chloride and nitrate 

concentrations in the 2007 samples with samples collected 

previously in five wells since 1982 showed that concentrations 

of these constituents remained similar through time in samples 

from some wells but increased up to three-fold, especially for 

chloride, in others. The two wells with the largest increases 

in chloride were in a residential and commercial area along 

Route 209, a major transportation corridor in eastern Pike 

County.

Overall, based on this reconnaisance study, groundwater 

quality in Pike County is relatively good with no constituents 

exceeding any primary water-quality standards. The low levels 

of anthropogenic organic compounds detected and elevated 

concentrations of chloride and related constituents (boron 

and nitrate) relative to background levels indicate that human 

activities have influenced groundwater quality in some parts 

of the county.

Introduction

Pike County in northeastern Pennsylvania has experienced the largest relative population growth of any county in 

the state during the period 1990–2000 (U.S. Census Bureau, 

2000). The 2006 Pike County Comprehensive Plan update 

(Pike County Commissioners, 2006) estimated as much as 

a 20-percent increase in population by the year 2010, and 

continued substantial increases are projected through 2025. 

This growing population may result in added dependence and 

stresses on groundwater, the primary source for drinking water 

in the county. As the demand for acceptable water quantity and 

quality for drinking-water supplies increases, contaminants 

associated with land-use changes have the potential to degrade 

water quality. On-site wastewater disposal is widespread. 

Residential growth in Pike County is associated with probable commercial development and additional infrastructure 

will most likely be needed to meet the needs of the increasing 

population.

Extensive land-use changes have the potential to reduce 

the quantity and affect the quality of water that recharges the 

groundwater system and eventually discharges to streams. 

At present (2009), high-quality streams that support healthy 

aquatic life and provide recreational fisheries are important 

assets of the county. This evolving landscape presents Pike 

County officials with current and future challenges not only 

in maintaining adequate groundwater quantity and quality 

capable of sustaining the influx of new residents but also in 

preserving base flow and base-flow quality in county streams.

The most recent countywide assessment of groundwater resources was done in the early 1980s (Davis, 1989) and 

was limited in scope. After more than 20 years of development, little is known about the current quantity and quality of 

groundwater in Pike County. Pike County officials, charged 

with managing water resources, need reliable information that 

characterizes those resources and provides a basis for scientifically defensible decisions to preserve and (or) mitigate potentially impaired water resources throughout the county.

Characterization of groundwater quality is an essential 

component in the planning process. In 2007, the U.S. Geological Survey (USGS), in cooperation with the Pike County 

Conservation District (PCCD), began a countywide reconnaissance assessment of groundwater quality. This report presents 

current (2007) groundwater-quality conditions within the 

context of existing land uses and may serve as a baseline of 

groundwater quality for future comparison. The 2007 assessment in Pike County may also be used as a basis for comparison of groundwater quality in other areas of Pennsylvania 

and neighboring states and to evaluate groundwater quality in 

relation to geology and land use.

In 2007, the USGS, in cooperation with the PCCD, also 

established an observation-well network to monitor groundwater levels. With continued collection of water-level data, 

the observation-well network (U.S. Geological Survey, 2009a) 

may be used for monitoring long-term trends, drought, and 

(or) for prediction of low streamflow conditions.

Purpose and Scope

This report describes the methods used and results for 

a reconnaissance groundwater-quality assessment based on 

samples collected from 20 wells throughout Pike County in 

summer-fall 2007. Samples were analyzed for major ions, 
Introduction 3

nutrients, selected trace metals, volatile organic compounds 

(VOCs), selected organic wastewater compounds, gross 

alpha-particle and gross beta-particle activity, uranium, and 

radon-222. Analyses of the 20 samples were for dissolved 

constituents, but 6 samples were analyzed for both dissolved 

and total metals.

Measured concentrations of analyzed constituents in 

groundwater are compared to U.S. Environmental Protection 

Agency (USEPA) drinking-water standards. The relations 

between concentrations of dissolved and total metals for 6 of 

the 20 samples are presented. The relations between observed 

groundwater quality and the factors of geology and land use 

near the well are discussed. Chloride and nitrate concentrations in base flow at three Pennsylvania Department of 

Environmental Protection (PADEP) stream reference sites in 

Pike County briefly are discussed as an indicator of groundwater quality and land use. For five wells sampled at least twice 

from 1982 to 2007, the apparent change in groundwater quality through time is described.

Description of Study Area

Pike County covers 545 mi2 in northeastern Pennsylvania 

and is flanked on the north and east by the Delaware River, 

which forms the boundary between the county and the adjacent states of New York and New Jersey (fig. 1). Land-surface 

elevations are highest [over 2,000 ft above the North American 

Vertical Datum of 1988 (NAVD 88), formerly referred to as 

sea level] in the southwestern corner of the county and lowest 

along the Delaware River (as low as about 320 ft above NAVD 

88). Davis (1989) described the climate and general physical 

characteristics of the county.

Hydrogeologic Setting

Most of the county is underlain by Devonian-age 

fractured-rock aquifers (shales, siltstones, and sandstones) 

(fig. 1); high-yielding unconsolidated Quaternary-age glacial 

deposits are present in a band parallel to the Delaware River 

on the eastern edge of the county and in some upland stream 

valleys. These aquifers are recharged locally by precipitation and subsequently discharge to streams. In Pike County, 

local, intermediate, and regional groundwater-flow systems 

are thought to be present; local and intermediate flow systems 

discharge to streams and larger tributaries, respectively, and 

the deeper regional system discharges to the Delaware River 

(Davis, 1989). Only a small part of recharge is thought to enter 

and flow through the deeper regional flow system (Davis, 

1989). For the surface-water system, streams radiate from near 

the center of Pike County and eventually drain toward the 

Delaware River.

Berg and others (1980) mapped the bedrock geologic 

units that underlie Pike County, in order of decreasing age 

from east to west, as the Marcellus Formation, Mahantango 

Formation, Trimmers Rock Formation, Towamensing Member 

of the Catskill Formation, undivided Long Run and Walcksville Members of the Catskill Formation, and undivided 

Poplar Gap and Packerton Members of the Catskill Formation 

(fig. 1). These geologic units consist of sedimentary rocks that 

generally show a trend from finer-grained rocks (shales and 

siltstones) in the older units in the eastern part of the county 

to coarser-grained rocks (sandstones and conglomerates) in 

younger units in the western part of the county. Unconsolidated glacial deposits cover part of the bedrock units and vary 

in thickness and type. Davis (1989) describes the rock types, 

aquifer properties, and hydrogeology of the county in more 

detail. Alternate geologic mapping published by Davis (1989) 

shows the Delaware River and Laxawaxen Members of the 

Catskill Formation underlying the area mapped by Berg and 

others (1980) as the undivided Long Run and Walcksville 

Members of the Catskill Formation (fig. 1).

Land Use

As of 2005, the principal land uses in the county are 

public (33 percent), residential (24 percent), agricultural 

(23 percent), hunt club/private recreational (14 percent), 

roads (2 percent), and commercial (2 percent) (fig. 2) (Pike 

County Commissioners, 2006). The public lands include 

state park, state game, state natural area, and national park 

parcels, much of which are forested, as are hunt club parcels. 

Most of the land designated in agricultural use also is forested 

and privately owned, with little in actual cultivation or other 

agricultural operations. The 24 percent of land in residential 

use includes the classifications rural residential (4 percent), 

residential (10 percent), and vacant residential (10 percent).

Population has been growing in Pike County since 1940 

(Davis, 1989). The increase in population of Pike County 

from 1990 to 2000 was ranked 36th out of 3,141 counties in 

the United States, with an increase of 65.6 percent (or 18,366 

people) from a 1990 population of 27,966 to a 2000 population of 46,302 (U.S. Census Bureau, 2000). The period from 

1970 to 1980 also was a time of relatively large population 

growth, increasing 54.6 percent to a population of 18,271 in 

1980 (Davis, 1989). Because much land is public or private 

forested land, the population growth was in limited areas as 

can been seen by the distribution of residential land in Pike 

County (fig. 2). The largest population centers are the boroughs of Milford and Matamoras (fig. 1) in the eastern part of 

the county. In addition to the census population, use of land 

for recreation results in seasonal increases in population and 

potential stresses on the groundwater system and associated 

surface waters.

Groundwater is the main source of drinking water in the 

county. Individual on-site wells are common in many residential areas, although large wells supply some developments. 

The boroughs of Milford and Matamoras are served by public 

supplies whose sources are springs and wells, respectively. 

On-site wastewater disposal is common in residential areas; 

sand mounds are more commonly used than septic systems in 

recent developments (John Jose, Pike County Conservation 
4 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Figure 1. Geology of Pike County, Pa., showing bedrock geologic unit and extent of the glacial aquifer near the Delaware River and locations of 20 wells sampled by the U.S. Geological Survey in 2007.

GREENE

PORTER

DINGMAN

LEHMAN

LACKAWAXEN

SHOHOLA

BLOOMING GROVE

PALMYRA

DELAWARE

WESTFALL

MILFORD

MATAMORAS

BOROUGH

MILFORD BOROUGH

562

559

558

557

556

555

554

553 552

551

550

524

480

464

380

308

288

211

561

390

380562551

211

558308

75°15' 75° 74°45' 74°30'

41°30'41°15'

EXPLANATION

LAND USE NEAR WELL AND LOCAL WELL NUMBER (prefix PI- omitted)

MUNICIPALITY BOUNDARY: TOWNSHIP OR BOROUGH

CommercialPre-development (large-scale mixed-landuse development)Residential, high-density, on-site wastewater disposalResidential, moderate-density, on-site wastewater disposalResidential, seweredUndeveloped

BEDROCK GEOLOGIC UNIT

Poplar Gap and Packerton Members of Catskill Formation, undivided

Long Run and Walcksville Members of Catskill Formation, undividedTowamensing Member of Catskill FormationTrimmers Rock FormationMahantango FormationMarcellus Formation

0 6 12 MILES 3

0 10 20 KILOMETERS 5

WAYNE COUNTY

MONROE COUNTY

NEW YORK

NEW JERSEY

PENNSYLVANIA

Pike County

APPROXIMATE BOUNDARY OF GLACIAL AQUIFER BY DELAWARE RIVER

Geology from Miles and Whitfield, 2001 Base from U.S. Geological Survey digital data, 1972, 1:2,000,000 Albers Equal-Area Conic Projection Standard parallels 29°30’N, central meridian 77°45’W

D e l a

w a r e R i v e r

D e l a w a r e R vi e r
Introduction 

5

Figure 2. Land use in Pike County, Pa., in 2005 and locations of 20 wells sampled in 2007 and selected stream water-quality monitoring sites.

Route 6

I-84

Route 209

562

561

559

558

557 556

555

554

553

552

551

550

524

480

464 390

380

308

288

211

01432097

01431554

Kintz Creek

Blooming Grove Creek

562

561

559

558

557 556

555

554

553

552

551

550

524

480

464 390

380

308

288

211

01438760

01432097

01431554

Adams

Creek

Blooming Grove Creek

Kintz Creek

Route 739

75°15' 75° 74°45' 74°30'

41°30'41°15'

EXPLANATIONLAND USE

AgricultureBusiness parkCommercialHunt clubIndustrialOther club/private recreationPublic landsResidentialResidential vacantRoadRural residentialUtilitiesWater

GEOLOGIC UNIT OF WELL AND LOCAL WELL NUMBER (prefix PI- omitted)

Glacial outwash or kame terracePoplar Gap and Packerton Members of the Catskill FormationLong Run and WalcksvilleMembers of the Catskill FormationTowamensing Member of theCatskill FormationTrimmers Rock FormationMahantango Formation

WATERSHED

STREAM STATION AND NUMBER AND STREAM NAME

Base from U.S. Geological Survey digital data, 1972, 1:2,000,000, Albers Equal-Area Conic Projection Standard parallels 29°30’N, central meridian 77°45’W Land use from Pike County Commissioners, 2006

0 6 12 MILES 3

0 10 20 KILOMETERS 5

01438760

Adams

Creek

480555561551211558
6 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

District, oral commun., 2007). Some developments are sewered and have sewage-treatment systems that discharge treated 

effluent to land areas or to surface water.

Previous Investigations

A countywide assessment of groundwater resources, 

including evaluation of general groundwater quality (major 

ions, nutrients, iron, and manganese) and, for some samples, 

selected trace metals, was done in the early 1980s (Davis, 

1989). An investigation of nitrate and chloride in the glacial 

aquifer underlying Route 209 north of Milford in Pike County 

was done in 1991 (Senior, 1994). In 2001, groundwater from 

four wells in the glacial aquifer near the Delaware River was 

sampled and analyzed for major ions, nutrients, trace metals, pesticides, volatile organic compounds (VOCs), and 

radon-222 as part of the National Water-Quality Assessment 

(NAWQA) in the Delaware River Basin (Durlin and Schaffstall, 2002). Pesticides were not detected in the 2001 samples 

and consequently were not included in the 2007 assessment 

described in this report.

Study Methods

To provide a current assessment of groundwater quality 

in Pike County, 20 wells throughout the county were selected 

to represent groundwater quality in the main land uses and 

geologic units were sampled in 2007. Although the main geologic units and land uses were included, the assessment should 

be considered a reconnaissance because of the small number 

of samples in each geologic unit or land-use category. The 

laboratory analyses selected for the samples were intended to 

identify naturally occurring constituents from the aquifer or 

anthropogenic constituents that pose a health risk or otherwise 

were of concern in groundwater in the county. The samples 

were analyzed for major ions, nutrients, selected trace metals, VOCs, a suite of organic wastewater compounds, gross 

alpha-particle and gross beta-particle activity, and radon-222. 

Descriptions follow of the sample locations and collection and 

analytical procedures for the 2007 reconnaissance groundwater-quality assessment in Pike County.

Selection of Sampling Locations

Wells in each of six main geologic units and six land-use 

categories (table 1) were selected for sampling to represent 

groundwater quality throughout the county (figs. 1 and 2). Of 

the six main geologic units, five are fractured-bedrock aquifers and one is an unconsolidated aquifer (kame terrace and 

outwash deposits by the Delaware River are considered as one 

glacial aquifer for this report). Other less-areally extensive glacial or alluvial deposits in upland areas or smaller stream valleys that may form aquifers were not sampled. The six landuse categories included commercial, high-density residential 

with on-site wastewater disposal, moderate-density residential 

with on-site wastewater disposal, residential in a sewered area, 

pre-development downgradient from the proposed largescale mixed-use land development, and undeveloped. For the 

residential areas with on-site wastewater disposal, relative 

density was determined from field observation where areas 

with lots generally about 1 acre or less were considered high 

density and areas with lots 2 acres or greater were considered 

moderate density. Two of the four wells (PI-308 and PI-556) 

in the undeveloped category are within the Delaware Water 

Gap National Recreation Area and the other two (PI-553 and 

PI-555) were near state park, state natural area, state game, or 

privately held game lands (fig. 2).

All sampled wells were domestic-supply wells serving 

individual residences. Well depth and other construction data 

were available for all but one of the wells sampled (table 1). 

Additional construction information can be found in table 10 

(at the back of the report).

Collection of Samples

Samples from 20 wells were collected from August 27 

through October 18, 2007. Sample collection and processing 

were done using standard methods (Wilde and others, 1999; 

Wilde and others, 2004). Groundwater samples were collected 

from wells using existing pumps and plumbing but bypassing 

any treatment systems. Water levels in the wells were measured prior to pumping, and wells were pumped until field 

measurements (pH, temperature, specific conductance, and 

dissolved oxygen concentration) stabilized before collecting 

the sample.

Samples for analysis of dissolved constituents were 

filtered in the field using a 0.45-micron polyethersulfone 

capsule filter. Samples for analysis of dissolved major cations 

and trace elements were preserved using nitric acid. Samples 

for organic wastewater compound analysis were unfiltered and 

collected in baked glass bottles; these samples were subsequently filtered through a glass-fiber filter at the laboratory 

before analysis. Samples for VOC analysis were collected in 

triplicate 40-mL vials and preserved with hydrochloric acid in 

the field.

Samples for age-dating by use of chlorofluorocarbons 

(CFCs), sulfur hexafluoride (SF6), and other dissolved gases 

(nitrogen, oxygen, argon, carbon dioxide, and methane) 

(Plummer and Friedman, 1999) were collected in glass bottles 

by methods described by U.S. Geological Survey (2009b). For 

the gas samples, bottles were filled through tubing connected 

to the pump and inserted into the bottle. Bottles were filled 

from the bottom up and allowed to overflow at least three 

volumes before capping. Samples for CFCs were collected 

through refrigeration-grade copper tubing in 125 mL glass 

bottles that are filled and capped underwater. Samples for 

SF6 were collected in plastic safety-coated 1-L glass bottles. 

Samples for the other dissolved gases (such as nitrogen) were 
Study Methods 7

Table 1. Geologic unit and land use for 20 wells sampled in Pike County, Pa., during the 2007 assessment.

[ft, feet; ft bls, feet below land surface; ft avd, feet above North American Vertical Datum of 1988; Geologic unit: Glacial units—112KMTC, Kame terrace; 

112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River 

Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the 

Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation; —, no data]

U.S. Geological

Survey

local well

number

Geologic

unit Land use Sampledate

Well 

depth

(ft)

Depth to 

water

(ft bls)

Altitude 

of land 

surface

(ft avd)

Wells listed by geologic unit

PI-480 112KMTC Residential, high-density, on-site wastewater 20070905 213 88.24 465

PI-464 112OTSH Commercial 20070828 142 17.32 430

PI-308 112OTSH Undeveloped 20070830 108 29.94 350

PI-288 341PGPK Residential, moderate-density, on-site wastewater 20070906 151 49.25 1,650

PI-555 341PGPK Undeveloped 20070830 380 116.92 1,789

PI-390 341DLRV1 Commercial 20071002 325 34.70 1,340

PI-557 341LRBW Residential, high-density, on-site wastewater 20070904 350 49.80 1,433

PI-561 341LRBW Residential, high-density, on-site wastewater 20071002 250 94.86 1,301

PI-559 341LRBW Residential, moderate-density, on-site wastewater 20070912 400 — 1,259

PI-553 341LRBW Undeveloped 20070829 610 124.35 1,510

PI-551 341TMSG Residential, high-density, on-site wastewater 20070828 250 58.28 1,110

PI-524 341TMSG Residential, moderate-density, on-site wastewater 20071001 380 56.82 1,139

PI-550 341TMSG Residential, moderate-density, on-site wastewater 20070827 250 54.08 1,207

PI-380 341TMRK Commercial 20070905 98 — 900

PI-562 341TMRK Pre-development (large-scale mixed-use development) 20071018 200 18.06 840

PI-554 341TMRK Residential, high-density, on-site wastewater 20070829 238 77.82 1,055

PI-211 341TMRK Residential, moderate-density, on-site wastewater 20070827 450 71.15 712

PI-552 341TMRK2 Residential, moderate-density, on-site wastewater 20070828 — 65.88 975

PI-558 344MNNG Residential, sewered 20070905 300 16.42 440

PI-556 344MNNG Undeveloped 20070830 400 54.05 719

Wells listed by land use

PI-380 341TMRK Commercial 20070905 98 — 900

PI-390 341DLRV1 Commercial 20071002 325 34.70 1,340

PI-464 112OTSH Commercial 20070828 142 17.32 430

PI-480 112KMTC Residential, high-density, on-site wastewater 20070905 213 88.24 465

PI-551 341TMSG Residential, high-density, on-site wastewater 20070828 250 58.28 1,110

PI-554 341TMRK Residential, high-density, on-site wastewater 20070829 238 77.82 1,055

PI-557 341LRBW Residential, high-density, on-site wastewater 20070904 350 49.80 1,433

PI-561 341LRBW Residential, high-density, on-site wastewater 20071002 250 94.86 1,301

PI-211 341TMRK Residential, moderate-density, on-site wastewater 20070827 450 71.15 712

PI-288 341PGPK Residential, moderate-density, on-site wastewater 20070906 151 49.25 1,650

PI-524 341TMSG Residential, moderate-density, on-site wastewater 20071001 380 56.82 1,139

PI-550 341TMSG Residential, moderate-density, on-site wastewater 20070827 250 54.08 1,207

PI-552 341TMRK2 Residential, moderate-density, on-site wastewater 20070828 — 65.88 975

PI-559 341LRBW Residential, moderate-density, on-site wastewater 20070912 400 — 1,259

PI-558 344MNNG Residential, sewered 20070905 300 16.42 440

PI-562 341TMRK Pre-development (large-scale mixed-use development) 20071018 200 18.06 840

PI-308 112OTSH Undeveloped 20070830 108 29.94 350

PI-553 341LRBW Undeveloped 20070829 610 124.35 1,510

PI-555 341PGPK Undeveloped 20070830 380 116.92 1,789

PI-556 344MNNG Undeveloped 20070830 400 54.05 719 1

Mapped as 341LRBW by Berg and others (1980).

2

Depth of well unknown and geologic unit for well completion based on bedrock mapping at well location, where geologic units are relatively flat lying and 

domestic wells are generally less than 500 feet in depth.
8 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

collected in 150 mL glass bottles that were filled and capped 

underwater.

Analysis of Samples

Selected physical and chemical constituents were measured while sampling each well. The pH, water temperature, 

acid-neutralizing capacity (ANC), specific conductance, and 

dissolved oxygen concentration for groundwater samples were 

measured in the field using standard methods (U.S. Geological 

Survey, variously dated).

Water samples were sent to the USGS National WaterQuality Laboratory (NWQL) in Denver, Colo., for analyses 

of inorganic constituents, organic compounds, and radon222. Analyses for dissolved inorganic constituents included 

major ions (calcium, magnesium, sodium, potassium, silica, 

sulfate, chloride, and fluoride), nutrients (nitrate, nitrite, 

ammonium, and orthophosphate), and selected trace elements 

and metals (arsenic, boron, cobalt, copper, iron, manganese, 

mercury, molybdenum, nickel, selenium, uranium, and zinc). 

In addition, unfiltered samples from 6 of the 20 wells were 

analyzed for selected total metals (arsenic, copper, iron, lead, 

and manganese). Analyses for organic compounds included a 

suite of about 65 compounds commonly present in domestic 

or industrial wastewater (such as detergent metabolites, food 

additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic 

aromatic hydrocarbons, and high-use domestic pesticides) 

(Zaugg and others, 2002; Zaugg and Leiker, 2006). Many of 

these wastewater compounds are potential endocrine-disrupters (compounds that disturb normal biological processes) or 

are toxic. Samples for gross alpha-particle and gross betaparticle activity at 72-hours and 30-day counting times were 

analyzed at a private laboratory under contract to the NWQL. 

Water samples for age-dating by CFCs and SF6 were analyzed 

by the USGS Chlorofluorocarbon Laboratory in Reston, Va., 

using methods described by U.S. Geological Survey (2009b) 

and by Busenberg and others (2006). Results of all analyses 

are presented in tables 11–15 at the back of the report.

For quality assurance, a field blank sample was collected 

at well PI-557 and analyzed for dissolved inorganic constituents, nutrients, trace metals, VOCs, and organic wastewater 

compounds. Results showed that none of the constituents or 

compounds analyzed for in the blank were detected, indicating 

that field equipment or sampling methodology did not contaminate the sample. No additional quality-assurance samples 

were collected; however, quality-assurance samples such as 

replicates and blanks collected for other studies using the same 

equipment, personnel, and procedures within 2 years of this 

study resulted in few to no apparent quality-assurance problems for these constituents (Senior and Cinotto, 2007). For the 

analysis of organic wastewater compounds, the NWQL adds 

compounds (surrogates) to the environmental sample that are 

similar chemically to some compounds analyzed to determine 

the relative sensitivity of the analysis to measure these types 

of compounds. The percent recovery reported by the NWQL 

for surrogates added to the samples undergoing analysis for 

wastewater compounds (see table 13 at the back of the report) 

were within the range commonly reported by NWQL (Zaugg 

and Leiker, 2006) for all but surrogate bisphenol-A-d3, for 

which the recoveries were very low. The very low surrogate 

recoveries indicate that the laboratory results for the compound bisphenol-A are questionable. For other surrogates, the 

recoveries indicate acceptable analytical results but are of limited use for assessing method compound recoveries because 

the surrogates are not necessarily chemically representative of 

every method compound (Zaugg and others, 2002).

The concentrations of major ions typically are reported 

in milligrams per liter, which are approximately equivalent 

to parts per million. Nitrogen compounds, such as nitrate 

and ammonia, are reported in milligrams per liter as nitrogen 

(as N), and phosphorus compounds, such as orthophosphate, 

are reported in milligrams per liter as phosphorus (as P). The 

concentrations of trace elements and organic compounds typically are reported in micrograms per liter, which are approximately equivalent to parts per billion.

Groundwater-Quality Assessment

The groundwater-quality assessment was intended to 

provide data on the occurrence in Pike County groundwater of 

naturally occurring constituents and constituents introduced 

by human activities. The 2007 assessment may be used to 

evaluate overall groundwater quality in the county, identify 

constituents that may pose a health risk, identify areas where 

land use may have impacted groundwater quality, and serve 

as a baseline for future evaluations to determine the effect of 

land-use changes on groundwater quality.

Both naturally occurring constituents and constituents 

introduced by human activities may pose a risk to human 

health when present at elevated concentrations in groundwater 

used for drinking-water supply. The USEPA has established 

maximum contaminant levels (MCLs) for some constituents 

in drinking water to protect human health. These MCLs may 

be used as a guideline for private well owners but must be 

followed for public drinking-water supplies. Other non-regulatory drinking-water standards include health advisory (HA) 

levels, listed by USEPA for selected constituents that have no 

MCL or, in some cases, in addition to the MCL, and secondary 

maximum contaminant levels (SMCLs) for selected constituents that pose no health risk but at a certain concentration may 

have adverse effects, such as taste or staining, on the use of 

water.

A discussion of the analyzed constituents in water from 

20 wells sampled in 2007 in Pike County follows. Complete 

results for laboratory analyses of groundwater samples collected in 2007 are listed in tables 11–15 at the back of the 

report.
Groundwater-Quality Assessment 9

Inorganic Constituents

The amount and relative proportion of inorganic constituents in groundwater reflect dissolution of minerals in 

the soils and aquifer materials and other chemical processes 

in the subsurface. In addition, some constituents are present 

in precipitation that recharges the aquifer but also may be 

introduced into the aquifer by recharge from areas affected 

by human activities. For example, sodium and chloride are 

present in low concentrations in precipitation in Pike County 

(table 2) and also may be introduced to groundwater in areas 

that receive salt from highway deicing or through discharge of 

septic-system effluent.

Although precipitation is relatively dilute, as a result of 

evaporation, conservative constituents in precipitation can 

become more concentrated in recharge. The concentration of 

conservative constituents in recharge derived from precipitation may be estimated to be about twice of that in precipitation, on the basis of rates of recharge relative to precipitation from Davis (1989). Thus, the concentration of chloride 

from precipitation in recharge would be about 0.5 mg/L or 

twice that for average precipitation at Milford, Pa., in 2006 

(table 2). The concentrations of most analyzed constituents 

have remained relatively stable since precipitation monitoring 

began in 1982, with the exception of sulfate, nitrate, and pH 

(Lynch and others, 2007a). The concentrations of sulfate and 

nitrate and the level of acidity declined at Milford over that 

24-year period.

General Water Quality

Groundwater samples from about half of the 20 wells 

were slightly acidic. The median pH was 6.8, just below the 

neutral value of 7.0 pH units, and the pH was equal to or less 

than the SMCL lower limit of 6.5 in 9 (45 percent) of the 20 

samples (table 3). Precipitation that falls on Pike County is 

acidic, had an average pH of about 4.5 in 2006 (table 2), and 

is neutralized by reactions with soils and aquifer minerals. 

The ANC and specific conductance are properties that may be 

related to mineral dissolution. ANC consists largely of bicarbonate alkalinity. The specific conductance is proportional to 

the amount and type of dissolved charged ions in solution. In 

the groundwater samples from Pike County, ANC and specific 

conductance generally tended to increase with pH (fig. 3), suggesting that mineral dissolution results in reducing acidity.

Hardness of the water samples ranged from 23 to 

140 mg/L as calcium carbonate (CaCO3), which indicates the 

water is very soft (less than 75 mg/L as CaCO3) to soft (less 

than 140 mg/L as CaCO3). Hardness reflects the concentrations of calcium and magnesium ions, which are released into 

groundwater from the dissolution of calcium- and magnesiumbearing minerals. Hard water decreases lathering of soap and 

increases accumulation of mineral deposits in plumbing and 

cooking utensils. No health-related standards are established 

specifically for hardness in drinking water.

Dissolved oxygen concentrations were low (less than 

1 mg/L) in 9 (45 percent) of the 20 well samples. Low 

concentrations of dissolved oxygen are related to chemical 

or biochemical reactions that consume oxygen and may be 

associated with reducing conditions that promote the release of 

some metals. The chemical reactions that consume oxygen can 

be naturally occurring in soils or aquifer materials.

Major Ions

Major ions generally comprise most of the dissolved constituents in groundwater. The major ions consist of positively 

charged cations (calcium, magnesium, sodium, and potassium) balanced by negatively charged anions (bicarbonate, 

chloride, sulfate, and fluoride). Silica is a major constituent 

that commonly occurs as an uncharged ion. Nitrate, discussed 

in the section on nutrients, is an anion that sometimes may 

be present in large enough concentrations to be considered a 

major ion.

The range and median concentrations of major ions in 

water from 20 wells sampled in Pike County in 2007 are listed 

in table 3. In the 20 groundwater samples, the only drinkingwater standard exceeded for major ions was the sodium 

concentration in one sample (from well PI-524). The highest 

sodium concentration of 39.9 mg/L exceeded the HA level 

of 20 mg/L for individuals on sodium-restricted diets and the 

taste threshold SMCL value of 30 mg/L.

The concentrations of many major ions may be related 

to the concentrations of other major or minor constituents or 

to water-quality characteristics, such as pH. These relations 

provide information about the sources of the ions and chemical controls on these constituents in groundwater. The highest 

sodium concentration is associated with the highest boron 

concentration. Sodium concentrations are generally related to 

both chloride and boron concentrations (fig. 4), indicating salt 

Table 2. Annual average concentrations of selected 

constituents in precipitation at Milford, Pa., 2006.

[Source of data is Lynch and others (2007a) and Lynch and others (2007b); 

Concentration is weighted by volume; mg/L, milligrams per liter; mg/L as 

N, milligrams per liter as nitrogen; ng/L, nanograms per liter]

Chemical

constituent Concentration Units

pH 4.510 pH units

Calcium .077 mg/L

Sodium .133 mg/L

Magnesium .022 mg/L

Potassium .030 mg/L

Chloride .255 mg/L

Sulfate 1.418 mg/L

Nitrate as N .228 mg/L as N

Ammonia as N .163 mg/L as N

Mercury 7.500 ng/L
10 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Table 3. Minimum, median, and maximum values for well characteristics, field measurements, and concentrations of dissolved 

major ions and nutrients in groundwater samples collected from 20 wells in Pike County, Pa., in 2007.

[MCL, maximum contaminant level; HA, health advisory; SMCL, secondary maximum contaminant level; ft bls, feet below land surface; ft, feet; gal/min, 

gallons per minute; °C, degrees Celsius; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L as CaCO3, milligrams per 

liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; -, no standard or not applicable; <, less 

than; E, estimated value]

Constituent Units Number

of samples Minimum Median Maximum Drinking-water standard1

MCL HA SMCL

Well characteristics and sampling data

Depth of well ft bls 19 98 250 610 - - -

Depth to water level ft bls 18 16.4 55.5 124 - - -

Altitude of land surface ft 20 350 1,083 1,790 - - -

Flow rate, instantaneous, gal/min 20 2.5 5 15 - - -

Pump or flow period prior to 

sampling

minutes 20 53 90 190 - - -

Temperature, air °C 20 15 25 29 - - -

Field measurements of water quality

Dissolved oxygen mg/L 20 .1 3.3 10.8 - - -

Dissolved oxygen percent of saturation 20 0 30 94 - - -

pH standard units 20 5.7 6.8 8.3 - - 6.5–8.5

Specific conductance μS/cm 20 70 185 351 - - -

Temperature, water °C 20 9.2 11.1 12.6 - - -

Acid neutralizing capacity mg/L as CaCO3 20 12 53.5 114 - - -

Dissolved inorganic constituents

Calcium mg/L 20 5.5 15.9 46.9 - - -

Magnesium mg/L 20 1.12 5.9 11.3 - - -

Potassium mg/L 20 .20 .54 .80 - - -

Sodium mg/L 20 1.4 6.9 39.9 - 20 30-60

Chloride mg/L 20 .53 7.6 39.9 - - 250

Fluoride mg/L 20 .05E .09E .21 4 - 2

Silica as SiO2 mg/L 20 4.8 9.9 16.9 - - -

Sulfate mg/L 20 .4 11.7 29.6 - 500 250

Hardness mg/L as CaCO3 20 23 64.5 140 - - -

Dissolved nutrients

Ammonia mg/L as N 20 <.010 <.020 .063 - 30 taste 

threshold

Nitrite plus nitrate2 mg/L as N 20 <.04 .205 2.00 10 - -

Nitrite mg/L as N 20 3<.002 <.002 .47 1 - -

Orthophosphate mg/L as P 20 4<.006 .012 .055 - - -

1

From U.S. Environmental Protection Agency, 2006.

2

Because nitrite concentrations were low except for one sample, nitrate is nearly equivalent to nitrite plus nitrate.

3

Estimated values less than the reporting level were reported for eight samples at concentrations of E0.001 mg/L as N.

4

Estimated values less than the reporting level were reported for two samples at concentrations of E0.004 and E0.005 mg/L as N.
Groundwater-Quality Assessment 11

Figure 3. (A) Acid-neutralizing capacity and (B) specific conductance in relation to pH in 

groundwater samples collected from 20 wells in Pike County, Pa., in 2007.

0

20

40

60

80

100

120

0

50

100

150

200

250

300

350

400

5 6 7 8 9

pH

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER CENTIMETER

ACID-NEUTRALIZING CAPACITY, 

IN MILLIGRAMS PER LITER AS CaCO3

A

B
12 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

and possibly borax (a sodium borate compound) as sources of 

these ions in groundwater.

Chloride concentrations greater than a few milligrams 

per liter probably represent influence of human activities on 

groundwater quality. The amount of chloride from precipitation (table 2) probably contributes on average less than 1 mg/L 

of choride to recharge concentrations. Natural background 

concentrations of chloride in groundwater are estimated to 

range from 1 to 5 mg/L. Chloride concentrations were greater 

than 6 mg/L in water from 10 of 20 wells sampled in 2007, 

indicating that groundwater quality at and near the 10 wells 

may be affected by human activities such as use of de-icing 

salts on roads and(or) septic systems.

Nitrate and Other Nutrients

Nitrogen and phosphorus compounds occur naturally and 

are essential nutrients for plant growth. Nitrogen and phosphorus compounds also are present in elevated concentrations in 

domestic and municipal wastewater. Elevated concentrations 

of nutrients may result in impairment of surface waters (where 

impairment is related to algal growth) and may pose a health 

risk when consumed in drinking water. The principal soluble 

nitrogen compounds of nitrate (NO3

-

), nitrite (NO2

-

), and 

ammonia (NH4 

+

) were included in analyses of groundwater 

samples collected in 2007. Orthophosphate (PO4

-

), a soluble 

form of phosphorus, was also analyzed in the samples. The 

laboratory analyses determine nitrite plus nitrate so nitrite concentrations must be subtracted to obtain nitrate concentrations.

Ammonia is a reduced form of nitrogen, it is the predominant nitrogen compound in septic-tank effluent, and it oxidizes to nitrate in the presence of oxygen. Nitrite (NO2

-

) is a 

less-oxidized form of nitrogen than nitrate (NO3

-

) and may be 

formed during an intermediate step in nitrification, a process 

in which ammonia is oxidized. Nitrite also may accumulate in 

groundwater during denitrification (Smith and others, 2004), 

a process in which nitrate is reduced to nitrogen gas usually 

in the absence of oxygen. Nitrification and denitrification 

reactions generally are biologically mediated. In low-oxygen 

environments, ammonia and nitrite will be more stable than 

nitrate. Conversely, where oxygen is present in higher quantities, nitrate is the more stable form.

Low concentrations of ammonia, nitrite, nitrate and 

orthophosphate were measured in most of the 20 groundwater 

samples, and no drinking-water standards for these compounds were exceeded (table 3). Ammonia concentrations 

were less than the reporting level of 0.02 mg/L as N in all but 

6 groundwater samples that had concentrations ranging from 

0.025 to 0.063 mg/L as N. Nitrite concentrations were less 

than or equal to the reporting level of 0.002 mg/L as N in all 

but two groundwater samples that had concentrations of 0.005 

Figure 4. Chloride and boron concentrations in relation to sodium concentrations in groundwater 

samples collected from 20 wells in Pike County, Pa., in 2007.

0

10

20

30

40

50

60

70

80

90

0 10 20 30 40 50

CHLORIDE

BORON

OR

CHLORIDE, IN MILLIGRAMS PER LITER

BORON, IN MICROGRAMS PER LITER

SODIUM, IN MILLIGRAMS PER LITER
Groundwater-Quality Assessment 13

and 0.47 mg/L as N, respectively. The highest concentrations 

of nitrite and ammonia were measured in samples that had low 

dissolved oxygen concentrations (0.2 or less mg/L)

Nitrate concentrations (calculated by subtracting nitrite 

concentration from the reported sum of nitrite plus nitrate 

concentration) were less than 0.8 mg/L as N in all but one 

groundwater sample that had about 2 mg/L as N, suggesting 

that most nitrate concentrations are within the range of estimated natural background levels. An estimated concentration 

of nitrate derived from precipitation (table 2) in recharge is 

up to about 0.8 mg/L as N, assuming no nitrogen loss and that 

all ammonia was converted to nitrate. Nitrate can be reduced, 

however, in low-oxygen environments such as were observed 

in 9 (45 percent) of the 20 well samples that had dissolved 

oxygen concentrations less than 1 mg/L. Many of the low 

nitrate concentrations might be attributed to nitrate reduction 

in soils and in the groundwater system.

Orthophosphate concentrations were less than 0.02 mg/L 

as P in all but five groundwater samples that had concentrations ranging from 0.02 to 0.055 mg/L as P. Concentrations of 

orthophosphate greater than 0.02 mg/L in eastern Pennsylvania commonly represent slight enrichment from human-related 

sources (Andrew Reif, U.S. Geological Survey, oral commun. 

2008).

Trace Elements and Metals

The dissolved trace elements and metals selected for 

analyses included boron (an indicator of domestic wastewater), and iron and manganese (known water-quality problem 

constituents). Analyses also included a suite of the following 

constituents that may pose health risks and that have established drinking-water MCLs or HA levels: arsenic, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, 

selenium, and zinc (table 4). Complete results are listed in 

table 11 at the back of the report.

Boron occurs naturally but may be elevated above 

background levels in areas that receive recharge affected by 

Table 4. Minimum, median, and maximum values for concentrations of dissolved metals in groundwater samples collected from 20 

wells and concentrations of dissolved and total metals in groundwater from 6 of the 20 wells in Pike County, Pa., in 2007.

[MCL, maximum contaminant level; HA, health advisory; SMCL, secondary maximum contaminant level; μg/L, micrograms per liter; <, less than; -, no 

standard]

Constituent Minimum Median Maximum MCL HA SMCL

Dissolved metals in 20 groundwater samples (μg/L)

Aluminum <1.6 <1.6 7.9 - - -

Arsenic <.12 .29 3.5 10 2 -

Boron 5 8.8 77 - 1,000 -

Cadmium .04 .04 .08 5 - -

Chromium .06 .12 .14 100 - -

Copper .4 9.75 72.2 1,300 - 1,000

Iron 4 17.5 675 - - 300

Lead .08 .16 2.2 15 - -

Manganese .2 15.8 292 - 300 50

Mercury <.01 <.01 <.01 2 - -

Molybdenum .01 .01 1.5 - 40 -

Nickel .09 .3 2.7 - 100 -

Selenium .04 .08 1.3 50 - -

Zinc 4 6 73 - 2,000 5000

Dissolved and total metals in a subset consisting of 6 of 20 groundwater samples (μg/L)

Arsenic, total .1 1.3 3.9 10 2 -

Arsenic, dissolved .09 .34 .69 10 2 -

Copper, total 7.1 18.45 92.2 1,300 - 1,000

Copper, dissolved .97 10 32.4 1,300 - 1,000

Iron, total 237 4,230 8,760 - - 300

Iron, dissolved 14 89 675 - - 300

Lead, total .34 1.09 11.8 15 - -

Lead, dissolved <.12 <.12 .3 15 - -

Manganese, total 12.4 200 361 - 300 50

Manganese, dissolved 2.2 169 248 - 300 50
14 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

wastewater, such as septic-tank effluent. Boron minerals, 

such as borax (sodium borate), commonly are used as laundry additives. Based on relations between sodium, chloride, 

and boron (fig. 4), boron concentrations less than 20 μg/L 

probably represent natural background levels in Pike County. 

Boron concentrations of 20 μg/L or greater are associated with 

elevated chloride concentrations (greater than 20 mg/L) and 

probably represent some contributions from anthropogenic 

sources and were measured in 6 of 20 groundwater samples in 

2007; the maximum concentration was 77 μg/L (table 4 and 

table 11 at the back of the report).

Concentrations of dissolved iron and manganese previously were reported to be elevated above SMCLs of 300 μg/L 

and 50 μg/L, respectively, in groundwater samples collected 

in a countywide assessment in 1982 (Davis, 1989). In the 

1982 study, iron concentrations were greater than the SMCL 

of 300 μg/L in 4 (7 percent) of 59 samples, and manganese 

concentrations were greater than the SMCL of 50 μg/L in 23 

(40 percent) of 58 samples. The 2007 assessment also shows 

concentrations of dissolved iron and manganese in groundwater samples elevated above the SMCLs; the maximum concentrations were 675 and 292 μg/L, respectively (table 4). In 

the 2007 study, concentrations of dissolved iron were greater 

than 300 μg/L in 3 (15 percent) of 20 samples, and concentrations of dissolved manganese were greater than 50 μg/L in 7 

(35 percent) of 20 samples. Two samples in 2007 had dissolved manganese concentrations (267 and 292 μg/L) close to 

the HA of 300 μg/L. In 2007, most concentrations of dissolved 

iron and manganese above the SMCLs of 300 and 50 μg/L, 

respectively, were in groundwater samples with low dissolved 

oxygen concentrations (0.2 mg/L or less) (fig. 5), which indicates geochemical control on concentrations of these metals.

Of the other dissolved metals analyzed in the 2007 

assessment, none were present in concentrations that exceeded 

established MCLs (table 4). The concentration of 3.5 μg/L 

for dissolved arsenic in one groundwater sample (from well 

PI-464), however, was greater than the HA level of 2 μg/L. 

This sample also had the highest concentration (0.055 mg/L as 

P) of orthophosphate, an ion that can interfere with sorption of 

arsenic ions on aquifer materials, suggesting that this relatively high arsenic may occur partly as a result of the elevated 

orthophosphate concentration. Dissolved arsenic concentrations in the other 19 groundwater samples ranged from less 

than 0.12 to 0.83 μg/L.

The concentrations of some metals may be above natural 

background levels. Concentrations of dissolved copper and 

zinc greater than 20 μg/L are associated with acidic water 

(pH less than 6.5) (fig. 6), suggesting that copper and zinc 

might be leached from household plumbing. Copper and zinc 

are common components in the manufacture of metal pipes 

and plumbing fixtures and are susceptible to dissolution in 

acidic water. The highest concentration of dissolved copper 

(72 μg/L) was in the same sample that had the highest concentration of dissolved zinc (73 μg/L).

Mercury was selected for analysis because of the mercury-related fish advisories issued by the PADEP for lakes 

in Pike County (Pennsylvania Department of Environmental 

Protection, 2009). Dissolved mercury was not detected in any 

of the groundwater samples collected in 2007. The laboratory 

reporting level for mercury in water is 0.01 μg/L. Mercury is 

present in precipitation in Pike County at an average concentration of about 7.5 nanograms per liter (ng/L) (table 2), which 

is equivalent to 0.0075 μg/L. If all the mercury in precipitation 

entered the aquifers through recharge, the mercury concentration in recharge would be no greater than about 0.015 μg/L, 

or just above the laboratory reporting level for water analysis. 

Based on results from the 2007 assessment, dissolved mercury 

was not elevated above the detection level and does not appear 

to be a problem in groundwater in Pike County.

Relation Between Dissolved and Total Major Ions and 

Metals

Most groundwater samples collected and analyzed by 

USGS in Pike County and elsewhere have been analyzed for 

dissolved constituents. Major ions are predominantly in the 

dissolved phase in groundwater, as can be seen by comparing 

filtered and unfiltered samples from a well (PI-308) in Pike 

County. Major ion concentrations in the sample collected and 

analyzed for dissolved ions in this study were about the same 

as in the sample collected a week later for a different study 

and analyzed for total constituents (table 5). The difference 

between total and dissolved concentrations represents the concentration of particulate phase in the sample, which typically 

is negligible for major ions.

However, the particulate phase may be important for 

some trace metals. Treatment of water to reduce unwanted 

levels of constituents partly depends on how that constituent occurs. For example, a sediment filter may remove most 

of the constituent in the particulate phase but little to none 

of the constituents in the dissolved phase. To investigate the 

relation between dissolved and total concentrations of a few 

metals, 6 of the 20 groundwater samples collected in 2007 

were selected for additional analyses of total metals—arsenic, 

copper, lead, iron, and manganese. Iron and manganese oxides 

can form particulates that are present in groundwater and may 

act to adsorb other metals. The samples selected for additional 

analyses represent a range of chemical characteristics (pH, 

specific conductance, and dissolved oxygen concentration) 

as well as different geologic units and land uses (see wells 

PI-390, PI-550, PI-553, PI-554, PI-556, and PI-562 in table 11 

at the back of the report). However, because only six samples 

were analyzed for dissolved and total concentrations, results 

may not be representative of the county as a whole.

Results show that total concentrations of some metals 

can be much higher than concentrations of dissolved metals in 

groundwater in Pike County, indicating that these metals occur 

in higher concentrations in the particulate phase than in the 

dissolved phase. Because the number of samples analyzed for 

dissolved and total metal concentrations was relatively small 

(6), results should be considered indicative rather than definitive for the countywide assessment.
Groundwater-Quality Assessment 15

0

100

200

300

400

500

600

700

800

0

50

100

150

200

250

300

350

0 2 4 6 8 10 12

SECONDARY MAXIMUM CONTAMINANT LEVEL

SECONDARY MAXIMUM CONTAMINANT LEVEL

DISSOLVED IRON, IN MICROGRAMS PER LITER DISSOLVED MANGANESE, IN MICROGRAMS PER LITER

DISSOLVED OXYGEN CONCENTRATION, IN MILLIGRAMS PER LITER

A

B

Figure 5. Concentrations of (A) dissolved iron and (B) dissolved manganese in relation to 

dissolved oxygen concentrations in groundwater samples collected from 20 wells in Pike 

County, Pa., in 2007.
16 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

0

10

20

30

40

50

60

70

80

0

10

20

30

40

50

60

70

80

5 6 7 8 9

pH

DISSOLVED COPPER, IN MICROGRAMS PER LITER DISSOLVED ZINC, IN MICROGRAMS PER LITER

A

B

Figure 6. Concentrations of (A) dissolved copper and (B) dissolved zinc in relation to pH in 

groundwater samples collected from 20 wells in Pike County, Pa., in 2007
Groundwater-Quality Assessment 17

Table 5. Concentrations of major ions, iron, and manganese in filtered and unfiltered samples from 

well PI-308 collected August 30 and September 9, 2007, respectively, in Pike County, Pa.

[mg/L, milligrams per liter; μg/L, micrograms per liter; <, less than; —, could not calculate for less-than values]

Filtered1

(collected 

8/30/2007)

Unfiltered2

(collected 

9/6/2007)

Absolute

difference3

Percent

difference4

Calcium (mg/L) 8.93 9.38 0.45 5.0

Magnesium (mg/L) 1.83 1.84 .01 .5

Potassium (mg/L) .73 .78 .05 6.8

Sodium (mg/L) 6.24 6.40 .16 2.6

Fluoride (mg/L) <.10 <.18 — —

Silica (mg/L) 9.00 8.95 -.05 -.6

Iron (μg/L) 373 3,350 2,977 798.1

Manganese (μg/L) 20.4 33.6 13.2 64.7

1

 Filtered samples yield results for dissolved constituents.

2

 Unfiltered samples yield results for total constituents (dissolved plus particulate).

3

 Absolute difference = unfiltered concentration - filtered concentration.

4

 Percent difference = 100 × (absolute difference/filtered concentration)

The largest differences between dissolved and total 

concentrations were for iron. Concentrations of total iron were 

from about 90 to 8,300 μg/L greater than concentrations of 

dissolved iron, and in samples from two wells (PI-390 and 

PI-550), were more than 100 times greater than dissolved iron 

concentrations (fig. 7, table 11 at the back of the report). The 

difference between total and dissolved iron concentrations is 

the concentration of particulate iron, which represented from 

about 38 to more than 99 percent of iron measured in the 

samples. The SMCL of 300 μg/L was exceeded in two of the 

six groundwater samples analyzed for dissolved iron and in 

five of the six groundwater samples analyzed for total iron, 

suggesting that particulate iron may be a water-quality problem more frequently in Pike County than dissolved iron. The 

cause of high concentrations of particulate iron is unknown, 

although high concentrations of particulate iron in some cases 

may be related to use of existing plumbing for collecting well 

samples despite pumping wells for 40 minutes or longer to 

flush plumbing before collecting samples, because particulate 

iron may accumulate in pressure tanks.

The ratio of total iron to dissolved iron concentrations 

appears generally related to dissolved oxygen concentrations 

in the six groundwater samples—total iron is higher relative to 

dissolved iron in water with more oxygen. In the two samples 

with oxygen concentrations greater than 1 mg/L, the concentrations of total iron were more than 100 times greater than 

concentrations of dissolved iron, whereas in most (3 of 4) samples with dissolved oxygen concentrations less than 1 mg/L, 

the concentrations of total iron were less than 20 times greater 

than concentrations of dissolved iron. This apparent result 

is consistent with higher concentrations of dissolved iron in 

water with less oxygen (fig. 5). Thus, in oxygenated groundwater, the potential for high concentrations of particulate iron 

is greater than for high concentrations of dissolved iron. About 

half (11 of 20) the wells in the 2007 assessment had dissolved 

oxygen concentrations greater than 1 mg/L.

For metals other than iron, relative differences between 

total and dissolved concentrations (measured as a ratio of 

total to dissolved concentrations) generally were least for 

manganese and copper and somewhat higher for arsenic and 

lead. The ratio of total to dissolved concentrations was less 

than 1.3 for manganese in five of six samples and less than 

1.6 for copper in five of six samples. These results indicate 

manganese and copper mostly are present in the dissolved 

phase. Manganese concentrations exceeded the SMCL in four 

of the six groundwater samples for both dissolved and total 

manganese. The total manganese concentration of 361 μg/L in 

one groundwater sample (from well PI-562) exceeded the HA 

of 300 μg/L. No concentrations of dissolved or total copper 

exceeded the drinking-water standards.

The ratio of total to dissolved concentrations ranged 

from 7.1 to 18.9 for arsenic in 3 of 6 samples and was greater 

than 3.8 for lead in all 6 samples, indicating the particulate 

phase of arsenic and lead can be higher in concentration than 

the dissolved phase of these metals. The HA level of 2 μg/L 

was exceeded by total arsenic in one groundwater sample. No 

drinking-water standard was exceeded by concentrations of 

dissolved or total lead, although the maximum lead concentration measured in the study (11.8 μg/L) was for total lead 

(table 4).

Higher concentrations of total iron appear to be associated with higher concentrations of total arsenic and total lead 

in general (fig. 8) but not with higher concentrations of copper 

or manganese, suggesting perhaps that arsenic and (or) lead 
18 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Figure 8. Total arsenic and lead concentrations in relation to total iron concentrations in groundwater 

samples collected from six wells in Pike County, Pa., in 2007.

Figure 7. Dissolved and total concentrations of iron, in order of increasing total iron concentrations, in groundwater samples 

collected from six wells in Pike County, Pa., in 2007.

1

10

100

1,000

10,000

PI-556 PI-553 PI-550 PI-390 PI-554 PI-562

SECONDARY MAXIMUM CONTAMINANT LEVEL

DISSOLVED OR TOAL IRON CONCENTRATION,

IN MICROGRAMS PER LITER

WELL-WATER SAMPLE

(0.2)

(0.1)

(5.3)

(8.4)

(0.7)

(0.2)

DISSOLVED OXYGEN

CONCENTRATION, 

IN MILLIGRAMS 

DISSOLVED

TOTAL

(0.2) 

EXPLANATION

PER LITER

0

2

4

6

8

10

12

14

0 2,000 4,000 6,000 8,000 10,000

LEAD

ARSENIC

TOTAL ARSENIC OR LEAD, IN MICROGRAMS PER LITER

TOTAL IRON, IN MICROGRAMS PER LITER

EXPLANATION
Groundwater-Quality Assessment 19

may adsorb on iron oxide particles. Additional investigation 

would be needed to determine geochemical relations and processes controlling the distribution of metals between dissolved 

and particulate phases.

Organic Compounds

The organic compounds analyzed in samples for the 

2007 groundwater-quality assessment included human-made 

VOCs and organic wastewater compounds. Detection of these 

compounds in groundwater indicates infiltration of recharge 

affected by human activities.

Volatile Organic Compounds

VOCs largely consist of human-made organic compounds, many of which commonly are used as solvents, such 

as trichloroethylene (TCE). VOCs may be associated with 

industrial activities and may be present in septic-tank effluent. Of the 29 regulated VOC compounds analyzed in the 20 

groundwater samples, only 3 were detected at or above the 

reporting level: 1,1,1-trichloroethane (TCA) at 0.2 μg/L, 

trichlorofluoromethane (Freon-11) at 39 μg/L, and trichloromethane (TCM, also known as chloroform) at 0.8 μg/L 

(table 6). Samples from three wells (PI-554, PI-556, and 

PI-559) each had only one of these VOC compounds (chloroform, Freon-11, and TCA, respectively) (table 12 at the back 

of the report). Thus, 3 (15 percent) of 20 groundwater samples 

had at least 1 VOC, but the detection frequency of each VOC 

was 1 (5 percent) of 20 groundwater samples. The concentrations of TCA, Freon-11, and chloroform in the samples did 

not exceed any established USEPA drinking-water standards 

(table 6). Although the measured VOC concentrations do not 

pose an established health risk, the detection of these humanmade compounds in groundwater indicates a low level of 

groundwater contamination by human activities.

TCA has been used as an industrial solvent, but its use is 

being phased out since 1996 as part of an international treaty 

to reduce gases that have a role in depleting the ozone layer 

of the earth (United Nations Environment Programme, 2006). 

Freon-11 was widely used as a refrigerant until 1996, when 

its use and uses of some other gases were banned because of 

their role in depleting the ozone layer. Chloroform is used as a 

solvent and reagent in synthesis of organic chemicals and can 

be produced as a by-product when chlorine bleach reacts with 

some other organic compounds in domestic wastewater.

Wastewater Compounds

Selected organic compounds present in industrial and 

domestic wastewater have been identified as having potential for endocrine disruption in living organisms. Methods to 

detect and measure these compounds at low concentrations 

in water (Zaugg and others, 2002) may provide sensitive 

indication of groundwater and surface-water contamination 

by wastewater. At present, drinking-water standards have 

been established for only a few of these organic wastewater 

compounds.

Of the 60 organic wastewater compounds analyzed, 5 

were detected at low levels in groundwater samples collected 

in Pike County in 2007 (table 6). Concentrations of these 

compounds in most samples were detected below the laboratory reporting level but could not be quantified (reported by 

the laboratory as “M,” meaning measured) and are considered 

trace levels. DEET (N,N-diethyl-meta-toluamide, an insect 

repellent) was the most frequently detected compound, being 

Table 6. Detected dissolved organic compounds in groundwater samples collected from 20 wells in Pike County, Pa., in 2007.

[MCL, maximum contaminant level; HA, health advisory; MRL, method reporting level; μg/L, micrograms per liter; M, measured but not quantified below 

MRL; —, minumum equals maximum because only one detection; -, no standard; E, estimated value below MRL; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran]

Organic compound

Number of 

samples with 

detections

Percent of 

samples with 

detection

MRL

Detected concentration

MCL

(μg/L)

HA

Minimum (μg/L) (μg/L)Maximum

(μg/L)

Volatile organic compounds

1,1,1-trichloroethane 1 5 <0.1 — 0.2 200 -

trichlorofluromethane 1 5 <.2 — 39 - 2,000

chloroform 1 5 <.1 — .8 180 70

Organic wastewater compounds

DEET 9 45 <0.1 - <0.2 M .2 - -

HHCB 3 15 <.5 M E.1 - -

tributyl phosphate 1 5 <.2 — M - -

triphenyl phosphate 1 5 <0.1 - <0.2 — E.1 - -

tris(2-butoxyethyl) phosphate 1 5 <0.4 - <0.5 — E.1 - -

1

Includes all trihalomethanes.
20 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

present in 9 (45 percent) of the 20 groundwater samples at 

concentrations below the reporting level. HHCB (hexahydrohexamethyl cyclopentabenzopyran, a fragrance) was detected 

in 3 (15 percent) of the 20 groundwater samples. Tributyl 

phosphate (a flame retardant), triphenyl phosphate (plasticizer, 

finish, flame retardant), and tris(2-butoxyethyl)phosphate 

(a flame retardant) were each detected in 1 (5 percent) of 

the 20 groundwater samples. In a national reconnaissance 

study of the occurrence of wastewater compounds in groundwater, DEET was the most frequently detected compound, 

measured in 35 percent of samples, and triphenyl phosphate 

was measured in about 4 percent of the samples (Barnes and 

others, 2008). All five of the organic wastewater compounds 

detected in groundwater in Pike County samples commonly 

have been found in surface waters affected by wastewater 

discharges (Kolpin and others, 2002; Focazio and others, 

2008; Tertuliani and others, 2008). In a study of the persistence of organic wastewater contaminants through a drinkingwater treatment plant, DEET, HHCB, tributyl phosphate, and 

tris(2-butoxyethyl) phosphate were present in raw and finished 

water (Stackelberg and others, 2004). Results from the 

drinking-water-treatment study suggest that these and other 

compounds may also persist in the natural environment.

At least one organic wastewater compound was detected 

in 10 of the 20 groundwater samples. Multiple organic wastewater compounds were detected in three groundwater samples. 

The sample from well PI-552 had the most (four) organic 

wastewater compounds detected (table 13 at the back of the 

report). Two organic wastewater compounds were detected 

in samples from wells PI-554 and PI-555, and only one 

wastewater compound was detected in the remaining seven 

groundwater samples with detections (PI-211, PI-308, PI-464, 

PI-480, PI-551, PI-556, and PI-557). Samples from two wells 

with detections of organic wastewater compounds (PI-554 and 

PI-556) also had one VOC detection.

Radionuclides

Radioactive elements or radionuclides occur naturally 

in geologic materials and may be present in soils, unconsolidated deposits, and bedrock. The principal parent radioactive 

elements are uranium, thorium, and potassium. The decay 

of radioactive parent elements through nuclear disintegration emits associated alpha particles, beta particles, and (or) 

gamma radiation and produces daughter products that may 

also be radioactive. The half-life of a radionuclide is the 

amount of time required for one-half of the original parent radionuclide to undergo radioactive decay. The activity 

is a measure of the rate of decay and, in water, commonly 

is expressed in units of picocuries per liter. One picocurie 

is equivalent to 2.2 nuclear disintegrations per minute. The 

USEPA (2006) has established or proposed drinking-water 

standards for only some radionuclides, including two radium 

isotopes (radium-226 and radium-228), gross alpha-particle 

and gross beta-particle activity, radon-222, and uranium.

Radon-222

Radon-222 is produced from the decay of radium-226, 

itself a daughter product in the uranium-238 decay chain. 

Radon-222 is a gas that is soluble in water. Radon-222 has a 

half-life of about 3.8 days and decays by alpha-particle emission to polonium-218 and a series of relatively short-lived 

radionuclides that are non-gaseous. Radon-222 has the longest 

half-life of the 34 isotopes of radon. Radon-222 may pose a 

health risk, especially when in air, and may be released into 

household air from well water when that water is used and 

agitated (as in showering or washing clothes).

The USEPA has proposed two standards for radon-222 in 

drinking water, a MCL of 300 pCi/L or the alternative MCL of 

4,000 pCi/L (U.S. Environmental Protection Agency, 2007). 

The standard of 4,000 pCi/L would be for public drinkingwater systems in states that implement management of multimedia mitigation programs (programs to address the health 

risks of radon-222 in indoor air) and the lower standard of 

300 pCi/L would befor public drinking-water systems in states 

that do not implement multimedia mitigation programs.

Radon-222 activities were greater than or equal to the 

proposed MCL of 300 pCi/L in water from 15 (75 percent) 

of the 20 wells sampled in Pike County in 2007. Radon-222 

activities did not exceed the alternative MCL of 4,000 pCi/L 

in any groundwater samples. The highest radon-222 activity 

measured was 2,650 pCi/L and was present at that level in 

water samples from two wells (PI-288 and PI-551) completed 

in members of the Catskill Formation (table 7 and table 14 at 

the back of the report).

Gross Alpha-Particle and Gross Beta-Particle 

Activity

During radioactive decay, alpha particles or beta particles 

are emitted depending on the radioactive isotope undergoing 

decay. For example, during decay, radium-226 releases alpha 

particles and radium-228 releases beta particles. The analyses 

for gross alpha-particle and gross beta-particle radioactivity measure the sum of each type of particle release rate and 

will include particles from all radionuclides present. Gross 

alpha-particle and gross beta-particle analyses in water do not 

identify which radionuclides are present but can be used to 

screen for elevated radionuclides.

The USEPA has established drinking-water standards 

for gross alpha-particle and gross beta-particle activities. The 

MCLs for gross alpha-particle and gross beta-particle activities are expressed in different units. The MCL of 15 pCi/L for 

gross alpha-particle activity uses the units as directly reported 

by the laboratory. The MCL for gross beta-particle activity is 

4 millirem per year, which is a dose and requires calculation 

on the basis of estimates of exposure and biological efficiency 

of specific radionuclides. The units of picocuries per liter cannot be directly converted to millirem without additional information. However, elevated levels of gross beta activity may be 
Groundwater-Quality Assessment 21

Table 7. Minimum, median, and maximum values for activities of dissolved radionuclides and uranium concentrations in groundwater 

samples collected from 20 wells in Pike County, Pa. in 2007.

[MCL, maximum contaminant level; HA, health advisory; SMCL, secondary maximum contaminant level; AMCL, alternative maximum contaminant level; 

R, radchem no detect; Th-230, thorium-230; Cs-137, cesium-137; pCi/L, picocuries per liter; -, no standard; μg/L, micrograms per liter; mrem/yr, millirem per 

year]

Constituent Units

Number of 

samples 

with

detections

Minimum Median Maximum MCL HA Remarks

Radon-222 pCi/L 20 90 610 2,650 300 150 AMCL of 4,000 pCi/L

Gross alpha-particle radioactivity1

72-hour count pCi/L 3 R-1.2 R0.1 2 15 -

30-day count pCi/L 0 R-2.4 R-0.2 R0.6 15 -

Gross beta-particle radioactivity2

72-hour count pCi/L 5 R-1.9 R0.4 1.4 4 mrem/yr - MCL expressed in 

terms of dose

30-day count pCi/L 7 R-0.4 R0.6 2.4 4 mrem/yr - MCL expressed in 

terms of dose

Uranium

(natural)

μg/L 17 3.03 .08 1.15 30 20

1

 Gross alpha-particle activity, based on Th-230 curve.

2

 Gross beta-particle activity, based on Cs-137 curve.

3

Value less than the reporting level of less than 0.04 μg/L was reported for one sample.
22 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

used to screen for presence of beta-emitting radionuclides that 

warrant further investigation.

Gross alpha-particle and gross beta-particle activities in 

samples collected from the 20 wells in 2007 were counted by 

the laboratory at two different times after collection, 72 hours 

and 30 days (table 14 at the back of the report), to provide 

information on the presence of radionuclides with half-lives of 

different lengths. Short-lived radionuclides decay quickly and, 

if present, will be associated with a decrease in radioactivity 

from 72 hours to 30 days. Increases in radioactivity over that 

time period indicate in-growth of longer-lived radionuclides in 

the water sample.

 None of the groundwater samples had elevated gross 

alpha-particle activities that exceeded drinking-water MCLs 

at either 72 hours or 30 days (table 7). The low level of 

gross beta-particle activities measured in the 20 groundwater 

samples (less than 3 pCi/L) probably do not correspond to an 

exceedence of the standard of 4 millirem per year. Many of the 

reported laboratory results were less than zero, indicating that 

background radiation in the laboratory analyses was greater 

than the radiation in these samples. Gross alpha-particle activities tended to be slightly higher in the 72-hour counts than 

in the 30-day counts, indicating the presence of short-lived 

alpha-particle emitters. Gross beta-particle activities tended 

to be slightly lower in the 72-hour counts than in the 30-day 

counts, indicating ingrowth of beta-particle-emitting radionuclides in the sample. Overall, the results indicate low potential 

for the presence of elevated activities of radionuclides other 

than radon-222 in the groundwater samples from Pike County 

in 2007.

Uranium

Uranium is a naturally occurring element with three natural isotopes—uranium-238, uranium-235, and uranium-234—

that are all radioactive. The long-lived uranium-238 is the 

most abundant uranium isotope in nature. Uranium measured 

by chemical methods, as was done for the 2007 assessment, 

typically includes all uranium isotopes present in the sample 

and is reported as natural uranium. The USEPA has established 

a MCL of 30 μg/L for uranium in drinking water on the basis 

of health risks posed by uranium metal toxicity, although some 

risk is caused by uranium radioactivity. The USEPA also lists a 

HA level of 20 μg/L for uranium.

None of the groundwater samples collected in Pike 

County in 2007 had uranium concentrations that exceeded 

either the HA of 20 μg/L or the MCL of 30 μg/L in drinking water (table 7 and table 14 at the back of the report). The 

highest uranium concentration in water from the 20 wells 

sampled was 1.15 μg/L. Thus, although the observed radon222 concentrations indicate that uranium probably is present in 

aquifer materials in Pike County, the uranium does not appear 

to dissolve in groundwater in concentrations large enough to 

exceed an established drinking-water standard.

Relation Between Groundwater Quality and 

Setting

Groundwater acquires solutes through natural and 

anthropogenic loading of constituents in the recharge area, 

including from precipitation, weathering reactions of minerals in the soil and aquifer materials, and constituents applied 

by human activities at or near the surface. Additional solutes 

may be acquired as groundwater flows through the aquifer. 

On the basis of the hydrogeology described by Davis (1989), 

groundwater that supplies most domestic wells completed in 

upland areas of Pike County in the fractured bedrock aquifer is 

derived principally from local recharge and will be influenced 

by land use and geology near the well. In wells completed in 

the glacial deposits along the Delaware River, some component of water in that aquifer may have originated in the upland 

bedrock areas but most water supplying a well is assumed to 

be derived locally.

Although the number of wells sampled in the 2007 

groundwater-quality assessment is too small to permit a rigorous statistical comparison of differences in groundwater quality among different land uses and geologic units, results are 

presented to infer some relations between groundwater quality 

and these factors.

Groundwater Quality and Geology

Naturally occurring constituents might be expected to differ among geologic units because of differences in mineralogy, 

recharge rates, traveltimes, and other aquifer characteristics. 

These constituents include most major ions, selected trace elements, and radionuclides.

Differences in concentrations of some constituents in 

groundwater from the six geologic units sampled were indicated by the limited data. These constituents included potassium, silica, sulfate, nitrite plus nitrate as nitrogen, selenium, 

and radon-222. Concentrations of potassium and nitrite plus 

nitrate as nitrogen tended to be higher in water from the glacial deposits and the Long Run and Walcksville Members of 

the Catskill Formation, undivided, than in water from the other 

geologic units. The higher permeability of the glacial deposits 

compared to soils on bedrock aquifers may explain the higher 

concentrations of nitrite plus nitrate as nitrogen. Sulfate and 

selenium concentrations also tended to be higher in water from 

the glacial deposits than from the other geologic units. Silica 

concentrations were highest in water from the Trimmers Rock 

Formation.

Radon-222 activities were highest in water from the 

bedrock aquifers and lowest in the water from the glacial 

deposits (fig. 9), perhaps reflecting in part the occurrence of 

uranium-bearing minerals in the aquifers. Radon-222 activities in groundwater ranged from 90 to 2,650 pCi/L (median 

of 1,150 pCi/L) for bedrock aquifers and ranged from 230 

to 490 pCi/L (median of 470 pCi/L) for the glacial deposits. 

Among the bedrock units, radon-222 activities appeared high-
Groundwater-Quality Assessment 23

0

500

1,000

1,500

2,000

2,500

3,000

341PGPK 341LRBW 341TMSG 341TMRK 344MNNG GLACIAL

Long Run and Walcksville Members of Catskill Formation, undivided

Mahantango Formation

Outwash (112OTSH) and Kame terrace (112KMTC)

Poplar Gap and Packerton Members of Catskill Formation, undivided

Towamensing Member of Catskill Formation

Trimmers Rock Formation

341PGPK

341LRBW

341TMSG

341TMRK

344MNNG

GLACIAL

PROPOSED MAXIMUM CONTAMINANT LEVEL

RADON-222, IN PICOCURIES PER LITER

EXPLANATION

GEOLOGIC UNIT

Figure 9. Radon-222 activities in groundwater samples from 20 wells in different geologic 

units, Pike County, Pa., 2007. (Geologic units are shown on fig. 2.)
24 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

est in water from the Poplar Gap and Packerton Members of 

the Catskill Formation, undivided (median of 2,540 pCi/L), 

followed by water from the Towamensing Member (median of 

2,460 pCi/L) and Long Run and Walcksville Members, undivided (median of 1,700 pCi/L), of the Catskill Formation; and 

lowest in water from the Trimmers Rock Formation (median 

of 150 pCi/L) (fig. 9). Montgomery (1969) noted that uranium 

minerals, a likely source of radon-222, occur in Catskill Formation rocks elsewhere in Pennsylvania.

Groundwater Quality and Land Use

Human activities at the land surface can contribute 

constituents or contaminants to groundwater. The predominant land uses associated with human activities that have the 

potential to affect groundwater quality in Pike County are 

residential and commercial. In Pike County, residential onsite wastewater disposal is common and has the potential to 

contribute salts (chloride compounds), nutrients (nitrogen and 

phosphorus compounds), boron (a laundry additive), VOCs, 

and organic wastewater compounds to groundwater. Bacteria 

and other compounds present in wastewater were not analyzed 

in this study but also have potential to affect groundwater 

quality. Large areas of paved surfaces (parking lots) near commercial zones and roads throughout the county have seasonal 

application of de-icing salts that may infiltrate into groundwater. Other compounds such as pesticides and herbicides, not 

included in this study, also may be applied near roadways, on 

lawns, or in agricultural areas.

Of the constituents included in analyses of the 20 groundwater samples collected in 2007 in Pike County, only a few 

differences in individual constituent concentrations among 

the different land uses were indicated by the limited data. 

Water from one (PI-556) of the four wells in the undeveloped 

area had a number of constituents that indicated unexpected 

contamination (such as Freon-11) that likely indicates nearby 

improper disposal of the chemical and is not related to the land 

use. Constituents with probable differences in concentrations 

among different land uses included chloride, nitrite plus nitrate 

as nitrogen, and manganese.

Chloride concentrations tended to be highest in groundwater from wells in the high- and moderate-density residential 

areas with on-site wastewater disposal and lowest in some 

of the undeveloped and sewered areas (fig. 10A, table 8). A 

water sample from a well in a commercial area also had an 

elevated (40 μg/L) chloride concentration. The highest boron 

and ammonia concentrations were in samples that also had 

elevated chloride concentrations from wells in commercial 

and residential areas with on-site wastewater disposal. The 

combination of elevated chloride, boron, and ammonia concentrations suggests septic effluent as a source. Road salt may 

be a main source of chloride in samples with elevated chloride 

concentrations but not elevated concentrations of boron or 

nitrogen compounds. Chloride concentrations were less than 

the estimated low-range natural background of 1 mg/L from 

precipitation in two of the wells in undeveloped areas.

Concentrations of nitrite plus nitrate as nitrogen tended 

to be higher in wells in high- and moderate-density residential areas with on-site septic and commercial areas (fig. 10B). 

Water samples from the two wells in the sewered residential 

and pre-development areas had among the lowest concentrations of chloride and nitrite plus nitrate as nitrogen as did two 

of the four wells in the undeveloped areas, suggesting human 

activities had less impact on water quality in those land-use 

areas.

Manganese concentrations tended to be lowest in water 

from wells in the high-density residential areas with on-site 

wastewater disposal and the sewered residential area compared 

to water from wells in other land-use areas. It is unknown why 

low manganese concentrations occurred in water from these 

areas.

The detection of VOCs in groundwater samples appears 

somewhat related to land use. VOCs were detected in water 

from only three wells, two (PI-554 and PI-559) in residential 

areas with on-site wastewater disposal and one (PI-556) in an 

undeveloped area with probable local contamination (table 8). 

The VOCs detected in water from wells in residential areas, 

TCA and chloroform, are likely associated with the on-site 

wastewater disposal. The well (PI-556) in the undeveloped 

area had 39 μg/L of freon-11, a compound used as a refrigerant and solvent whose presence and concentration indicate 

groundwater contamination by improper chemical disposal 

such as dumping. No VOCs or wastewater compounds were 

detected in the two wells in the sewered residential and predevelopment areas.

Of the five organic wastewater compounds detected in 

groundwater in Pike County, no strong relation between land 

use and detection in groundwater was apparent for DEET or 

HHCB. DEET was detected most often and was measured at 

very low levels in samples from about half of the 20 wells and 

in most categories of land use, including commercial, residential with on-site septic (high and moderate density), and 

undeveloped. The frequent detection of DEET at low levels in 

Pike County probably is related to the high mobility and persistence of DEET in the environment, as noted in other studies 

throughout the United States (Barnes and others, 2008). As 

described previously, all samples in Pike County were from 

residential wells and, thus, in areas where DEET may be used. 

HHCB was detected in water from three wells, two wells in 

residential areas with on-site wastewater disposal, and one 

well in an undeveloped area. HHCB, like DEET, commonly is 

detected in surface waters affected by wastewater discharges 

(Barnes and others, 2008; Focazio and others, 2008). However, the other three organic wastewater compounds, triphenyl 

phosphate, tributyl phosphate, and tris(2-butoxylethyl) phosphate, were each detected only once and were present in water 

samples from two wells (PI-211 and PI-552) in moderatedensity residential areas with on-site disposal.

Four groundwater samples had more than one organic 

wastewater compound or VOC detected and were from an area 

with residential on-site wastewater disposal land use and from 

an area with undeveloped land use. The sample with the most 
Groundwater-Quality Assessment 25

0

5

10

15

20

25

30

35

40

45

0

0.5

1.0

1.5

2.0

2.5

CHLORIDE, IN MILLIGRAMS PER LITER

NITRITE PLUS NITRATE, IN MILLIGRAMS 

PER LITER AS NITROGEN

CommercialHigh-density residential

with on-site wastewater disposal

Moderate-density residential

with on-site wastewater disposal

Sewered residentialPre-developmentUndeveloped

LAND USE NEAR WELL

A

B

ESTIMATED UPPER RANGE OF 

NATURAL BACKGROUND CONCENTRATION

ESTIMATED UPPER RANGE OF 

NATURAL BACKGROUND CONCENTRATION

Figure 10. Concentrations of (A) chloride and (B) nitrite plus nitrate as nitrogen in 

groundwater samples from 20 wells in different land-use areas, Pike County, Pa., 2007.
26 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Table 8. Detected organic wastewater and volatile organic compounds and concentrations of inorganic and nutrient 

wastewater indicators in groundwater samples collected from 20 wells in Pike County, Pa., in 2007.

[Shaded values indicate concentrations above estimated natural background. μg/L, micrograms per liter; mg/L, milligrams per liter; VOCs, volatile 

organic compounds; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; tb-phos, tributyl phosphate; tp-phos, 

triphenyl phosphate; t2b-phos, tris(2-butoxyethylphosphate); TCA, 1,1,1-trichloroethane; TCM, trichloromethane or chloroform; B, boron; Na, 

sodium, Cl, chloride; NH4 as N, ammonia as nitrogen; NO2+NO3 as N, nitrite plus nitrate as nitrogen; PO4 as P, orthophosphate as phosphorus; <, less 

than; E, estimated; M, measured but not quantified below method reporting level; Geologic unit: Glacial units—12KMTC, Kame terrace; 112OTSH, 

Olean outwash; 341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill 

Formation; Bedrock units—341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of 

the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

Well

number Geologic unit Organic wastewater compounds (μg/L) VOCs (μg/L)

DEET HHCB tb-phos tp-phos t2b-phos TCA freon-11 TCM

Commercial

PI-380 341TMRK

PI-390 341DLRV1

PI-464 112OTSH M

Residential, high-density, on-site wastewater

PI-480 112KMTC M

PI-551 341TMSG M

PI-554 341TMRK M M 0.8

PI-557 341LRBW M

PI-561 341LRBW

Residential, moderate-density, on-site wastewater

PI-211 341TMRK E0.1

PI-288 341PGPK

PI-524 341TMSG

PI-550 341TMSG

PI-552 341TMRK M E0.1 M E.1

PI-559 341LRBW 0.2

Residential, sewered

PI-558 344MNNG

Pre-development (large-scale mixed-use land development)

PI-562 341TMRK

Undeveloped

PI-308 112OTSH M

PI-553 341LRBW

PI-555 341PGPK 0.2 M

PI-556 344MNNG M 39.0 1

Mapped as 341LRBW by Berg and others (1980).
Groundwater-Quality Assessment 27

Table 8. Detected organic wastewater and volatile organic compounds and concentrations of inorganic and nutrient 

wastewater indicators in groundwater samples collected from 20 wells in Pike County, Pa., in 2007.—Continued

[Shaded values indicate concentrations above estimated natural background. μg/L, micrograms per liter; mg/L, milligrams per liter; VOCs, volatile 

organic compounds; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; tb-phos, tributyl phosphate; tp-phos, 

triphenyl phosphate; t2b-phos, tris(2-butoxyethylphosphate); TCA, 1,1,1-trichloroethane; TCM, trichloromethane or chloroform; B, boron; Na,

sodium, Cl, chloride; NH4 as N, ammonia as nitrogen; NO2+NO3 as N, nitrite plus nitrate as nitrogen; PO4 as P, orthophosphate as phosphorus; <, 

less than; E, estimated; M, measured but not quantified below method reporting level; Geologic unit: Glacial units—112KMTC, Kame terrace; 

112OTSH, Olean outwash; 341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member 

of Catskill Formation; Bedrock units—341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing 

Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

Well

number

Inorganic and nutrient wastewaster indicators (mg/L)

B Na Cl NH4 as N NO2+NO3 as N PO4 as P

Commercial

PI-380 28.0 17.8 39.9 0.059 <0.06 0.011

PI-390 13.0 3.9 5.4 .027 .63 .007

PI-464 5.4 4.3 5.3 <.020 1.19 .055

Residential, high-density, on-site wastewater

PI-480 5.3 13.2 38.1 <.020 .52 E.005

PI-551 10.0 9.2 30.1 <.020 .41 .009

PI-554 20.0 11.2 22.4 E.012 .22 <.006

PI-557 20.0 12.0 21.9 <.020 2.00 .029

PI-561 10.0 4.4 10.2 <.020 .41 .015

Residential, moderate-density, on-site wastewater

PI-211 20.0 14.1 26.8 .059 <.06 .011

PI-288 5.0 2.7 4.4 E.010 .56 .016

PI-524 77.0 39.9 24.4 .059 <.04 .020

PI-550 5.3 4.4 2.4 E.016 E.05 .011

PI-552 8.9 6.9 2.6 E.016 <.06 .011

PI-559 5.3 7.0 23.6 <.020 .32 .012

Residential, sewered

PI-558 8.7 3.1 1.6 <.020 E.04 .018

Pre-development (large-scale mixed-use land development)

PI-562 7.3 5.6 3.2 .025 <.04 E.004

Undeveloped

PI-308 8.2 6.2 9.8 <.020 .19 <.006

PI-553 5.3 7.8 .5 <.020 <.06 .020

PI-555 6.0 1.4 .9 <.020 .36 .021

PI-556 33.0 9.3 5.2 .063 E.04 .016
28 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

(four) organic wastewater compounds detected was from a 

well (PI-554) in a moderate-density residential area with onsite wastewater disposal. Two organic wastewater compounds 

and a VOC were detected in water from a well (PI-552) in a 

high-density residential area with on-site wastewater disposal. 

DEET and HHCB were detected in water from a residential 

well (PI-555) in an undeveloped area. DEET and Freon-11 

were detected in water from a well (PI-556) in an undeveloped 

area thought to be affected by contamination.

Relation Between Groundwater Quality and 

Surface-Water Quality

Groundwater discharge to streams is the source of stream 

base flow (groundwater component as opposed to runoff). 

Some constituents dissolved in groundwater, especially 

relatively soluble constituents that are not adsorbed onto soils 

or aquifer materials or readily degraded in the groundwater 

system, may be transported in groundwater and discharge to 

streams in the drainage area. In headwater areas and small 

streams, groundwater discharge originates locally. Multiple 

levels of groundwater flow systems may be present from 

shallow local flow to deeper regional flow. In Pike County, 

groundwater may also discharge to swampy areas and to lakes 

and ponds, whether naturally occurring or where created artificially by placement of dams on streams.

Data on stream water quality collected by USGS for 

PADEP are available for six stream sites in Pike County. These 

sites are sampled as part of the PADEP statewide waterquality network (WQN). Some sites in the WQN are identified by PADEP as reference sites to represent water quality 

in watersheds with low levels of human influence in different 

regions of the state and typically receive no direct discharges 

from human activities, such as wastewater treatment plants 

(WWTPs), and are sampled monthly for 5 years. Base-flow 

quality at these reference stream sites will reflect quality of the 

groundwater discharge to the streams. Three of the six WQN 

stream sites in Pike County are reference sites.

Chloride is a relatively conservative (remains in solution, unaffected by degradation, sorption, or other chemical 

processes) constituent in groundwater and surface-water 

systems and can be used, for example, to investigate the 

relation between groundwater and surface-water quality. In 

Pike County, stream water-quality data are available for one 

former WQN reference site (014738760 Adams Creek at 

Dingmans Ferry, WQN 192) and two current WQN reference sites (01432097 Blooming Grove Creek at Glen Eyre, 

WQN site 197 and 01431554 Kintz Creek at Romersville, 

WQN site 199) (fig. 2). Chloride concentrations in the lowest flows (less than 2 (ft3

/s)/mi2, estimated to represent base 

flow) at these sites ranged from 8.5 to 15.1 mg/L in Adams 

Creek (2002–2004), from 8.5 to 15.5 mg/L in Blooming Grove 

Creek (2005–2008), and from 3.9 to 5.5 mg/L in Kintz Creek 

(2005–2008); the medians were 11.8, 10.8, and 4.5 mg/L, 

respectively. Although overall chloride concentrations are relatively low, the higher chloride concentrations in stream base 

flow at Adams Creek and Blooming Grove Creek compared 

to Kintz Creek indicate higher levels of human influence in 

the Adams Creek and Blooming Grove Creek watersheds. 

The upper areas of Adams Creek and Blooming Grove Creek 

watersheds are in residential land-use areas with major roads 

(routes 739 and I-84, 6, respectively) whereas most of Kintz 

Creek is vacant residential land (fig. 2). On the basis of the 

results of the 2007 groundwater-quality assessment, areas in 

residential land use generally have higher chloride concentrations in groundwater than undeveloped areas in Pike County.

Nitrate is a less conservative constituent in the environment than chloride but may be relatively elevated in stream 

base flow in watersheds with elevated nitrate concentrations in 

groundwater. Nitrate concentrations in the lowest flows at the 

three WQN reference sites in Pike County ranged from less 

than 0.04 to 0.27 mg/L as N in Adams Creek (2002–2004), 

from less than 0.04 to 0.08 mg/L as N in Blooming Grove 

Creek (2005–2008), and from less than 0.04 to 0.12 mg/L as N 

in Kintz Creek (2005–2008); the medians were 0.10, less than 

0.04, and 0.07 mg/L as N, respectively. All the nitrate concentrations were low and within the range of estimated natural 

background levels. Of the three sites, Adams Creek had the 

highest chloride and nitrate concentrations, which probably 

reflects a higher degree of impact by human activities in that 

watershed compared to the other two.

Temporal Aspects of Groundwater Quality

Groundwater quality can change through time because 

of (1) changes in land use and sources at the land surface, 

(2) changes in recharge and direction of groundwater flow, or 

(3) transport and chemical reactions in the aquifer. Changes 

in groundwater quality may result in increased risks to human 

health if water-quality standards are exceeded or in other 

undesirable effects, such as elevated concentrations of iron 

and manganese, on non-consumptive water use. Some variability in groundwater quality may be seasonal if related to the 

natural hydrological cycle; other variability may show a trend 

reflecting long-term changes in land use.

Age of Groundwater

The age of groundwater may be used to evaluate potential 

for contamination by human activities in the recharge area. For 

example, young groundwater recharged within the last 5 years 

will be more affected by recent land use than old groundwater 

recharged more than 500 years ago. Techniques to date relatively young groundwater (less than 50 years old) have been 

developed using the concentration of anthropogenic gases 

(such as chlorofluorocarbons) released into the atmosphere 

that equilibrate with recharge (Busenberg and Plummer, 2000; 

Plummer, 2005; International Atomic Energy Agency, 2006). 

The technique actually dates the introduction of these gases 

to recharge rather than the age of the water itself. A statewide 
Groundwater-Quality Assessment 29

Table 9. Estimated apparent ages in years before 2007 for groundwater samples from four wells in Pike County, Pa., in 2007. Ages 

based on piston-flow model for gas in recharge. (Replicate samples analyzed for each well.)

[SF6, sulfur hexafluoride; CFC-11, trichlorofluoromethane; CFC-12, dichlorodifluoromethane; CFC-113, trichlorotrifluorothane; —, no data because sample 

bottle broken; contam., contaminated, sample could not be analyzed; NP, not possible ratio]

Well Replicate

Age in years, based on single gas Age in years, based on ratio of gases

SF6 SF6 local1 CFC-11 CFC-12 CFC-113 CFC-11/

CFC-12

CFC-113/

CFC-12

CFC-113/

CFC-11

PI-308 1 5.7 9.2 contam. contam. 19.2 NP NP NP

2 — — — — 19.2 NP NP NP

PI-553 1 38.7 40.7 49.7 53.2 50.2 36.2 30.2 28.7

2 39.2 40.7 50.7 53.7 51.7 40.2 32.7 29.2

PI-555 1 16.7 18.7 33.7 30.7 25.2 NP 22.2 16.7

2 16.7 18.7 34.2 30.2 25.7 NP 22.7 16.7

PI-556 1 contam. contam. contam. contam. contam. contam. contam. contam.

2 contam. contam. contam. contam. contam. contam. contam. contam.

1

Enrichment factor of 1.2 used for SF6 due to local use of gas estimated to be up to about 20 percent greater than Northern Hemisphere clean air levels for 

area 75-100 miles west of New York City based on data from Santella and others (2008).

study in Virginia used this approach to determine that all 

groundwater in fractured-rock terrains and most of the shallow 

groundwater in the unconsolidated Coastal Plain aquifers were 

susceptible to near-surface contamination (Nelms and others, 

2003). In general, younger water is most susceptible to nearsurface contamination but would be expected to flush out of 

the aquifer more quickly than older water.

Water from 4 of the 20 wells sampled in 2007 was 

selected for age-dating by analysis of the gases CFC-11 

(trichlorofluoromethane or CFCl3), CFC-12 (dichlorodifluoromethane or CF2

Cl2), CFC-113 (trichlorotrifluoroethane 

or C2F3Cl3), and SF6 (sulfur hexafluoride). The four wells 

(PI-308, PI-553, PI-555, and PI-556) were in relatively undeveloped areas of Pike County (fig. 2). Three of the wells were 

completed in bedrock and one well (PI-308) was completed in 

the glacial outwash or kame terrace aquifer near the Delaware 

River. Duplicate samples from each well were collected for 

analysis. Dissolved gas samples were also collected to allow 

calculation of recharge temperature and excess air (table 15 at 

the back of the report) for better estimation of age-dating by 

CFC and SF6 methods (Busenberg and Plummer, 1992; U.S. 

Geological Survey, 2009b).

Apparent ages ranged from 17 to 34 years and 39 to 

54 years for samples from two bedrock wells (PI-555 and 

PI-553, respectively) and from 6 to 19 years for the well in 

the glacial aquifer (PI-308) (table 9). The chlorofluorocarbons 

may be affected by chemical processes, such as sorption and 

degradation, to a greater extent than SF6, (Han and others, 

2006), and if CFC concentrations have been reduced by chemical processes, ages estimated from CFCs may be somewhat 

older than those estimated from SF6. Estimated ages from SF6

(table 9) are slightly younger than those estimated from CFCs. 

The water sample from well PI-556 could not be used for agedating because the sample had elevated levels of CFC-11 (also 

known as Freon-11), possibly from improper waste disposal in 

the area that resulted in groundwater contamination.

Change in Groundwater Quality through Time

Five of the 20 wells sampled in 2007 were sampled by 

USGS at least once before; the time elapsed between sampling 

ranged from 6 to 25 years. Two wells were in residential areas 

(PI-288 and PI-480), two wells were in commercial areas 

(PI-380 and PI-464), and one well was in an undeveloped area 

(PI-308) (fig. 2). All but one well (PI-288) are in the eastern, 

more-developed part of Pike County. Four of the five wells 

were sampled twice and one well (PI-480) was sampled three 

times. Samples collected at the different times were analyzed 

for major ions, nutrients, iron, and manganese, allowing for a 

comparison of a limited set of constituents. Because elevated 

concentrations of chloride and nitrite plus nitrate as nitrogen 

commonly were associated in the 2007 groundwater samples 

with the predominant types of development in Pike County, 

residential and commercial, comparison of these constituents 

are discussed.

Chloride concentrations showed little change in some 

well samples and large changes in others, suggesting changes 

related to development intensity vary spatially throughout the 

county. The chloride concentrations were relatively similar in 

samples collected in three of the wells (PI-288, PI-308, and 

PI-464) in different land uses (residential, undeveloped, and 

commercial, respectively) over time spans ranging from 6 to 

25 years, indicating relatively stable inputs. However, chloride concentrations in samples from two other wells increased 

substantially over time spans that ranged from 16 to 25 years 

(fig. 11A). Chloride concentrations tripled in water from 

well PI-380 in a commercial area and more than doubled in 

water from well PI-480 in a residential area to concentrations 

near 40 mg/L (table 11 at the back of the report). These large 
30 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

0

5

10

15

20

25

30

35

40

45

CHLORIDE, IN MILLIGRAMS PER LITER

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

PI-380 PI-464 PI-288 PI-480 PI-308

NITRITE PLUS NITRATE, IN 

MILLIGRAMS PER LITER AS NITROGEN

Commercial Residential, on-site wastewater Undeveloped

LESS

THAN

DETECTION

(25)

(25)

(25)

(25)

(16)

(16)

(16)

(16)

(6)

(6)

WELL-SAMPLE REPLICATES, WITH LAND USE

(25)

PRE-2007 SAMPLE

2007 SAMPLE

A

B

YEARS BETWEEN SAMPLES

Figure 11. Concentrations of (A) chloride and (B) nitrite plus nitrate as nitrogen in groundwater from five 

wells sampled at time intervals ranging from 6 to 25 years in the period from 1982 to 2007, Pike County, Pa.
Summary and Conclusions 31

increases in chloride concentrations were in water samples 

from wells along the Route 209 corridor.

Similar to chloride, concentrations of nitrite plus nitrate 

as nitrogen showed little change in some well samples and 

larger changes in others. Nitrogen compounds are not necessarily as conservative as chloride, however, and can change 

through time related to chemical reactions rather than to 

changes in the groundwater of the wells (PI-288, PI-308, and 

PI-380) in different land uses (residential, undeveloped, and 

commercial, respectively) over time spans ranging from 6 to 

25 years (fig. 11B). Concentrations of nitrite plus nitrate as 

nitrogen in samples from two other wells (PI-480 and PI-464) 

increased by 0.30 to 0.47 mg/L as N over 16-year time spans. 

The groundwater samples from well PI-480 in a residential 

area also showed a relatively large increase in chloride concentration, reflecting loads from potential septic and road-salt 

sources.

Summary and Conclusions

Pike County in northeastern Pennsylvania has experienced the largest relative population growth of any county in 

the state during the period 1990–2000, and its population is 

projected to increase substantially through 2025. This growing population may result in added dependence and stresses 

on water resources, including the potential to degrade the 

quality of groundwater and associated stream base flow with 

changing land use. The most recent county-wide assessment of 

groundwater resources done in the early 1980s was limited in 

scope and, after more than 20 years of development, little was 

known about the current quantity and quality of groundwater 

in Pike County.

In 2007, the U.S. Geological Survey, in cooperation 

with the Pike County Conservation District, began a study to 

provide current information on groundwater quality throughout the county that will be helpful for water-resource planning. 

The countywide reconnaissance assessment of groundwater 

quality documents current conditions with existing land uses 

and may serve as a baseline of groundwater quality for future 

comparison in Pike County. The 2007 assessment may also be 

used as a basis for comparison of groundwater quality in other 

areas of Pennsylvania and to evaluate groundwater quality in 

relation to geology and land use.

Pike County covers 545 square miles and is underlain by 

Devonian-age fractured-rock aquifers (shales, siltstones, and 

sandstones); high-yielding unconsolidated Quaternary-age 

glacial deposits are present in a band parallel to the Delaware River on the eastern edge of the county and in some 

upland stream valleys. These aquifers are recharged locally by 

precipitation and discharge to streams. The bedrock geologic 

units that underlie Pike County are, in order of decreasing age, 

Marcellus Formation, Mahantango Formation, Trimmers Rock 

Formation, Towamensing Member of the Catskill Formation, 

undivided Long Run and Walcksville Members of the Catskill 

Formation, and undivided Poplar Gap and Packerton Members 

of the Catskill Formation. Glacial deposits cover part of the 

bedrock units and vary in thickness and type.

As of 2005, the principal land uses in the county were 

public (33 percent), residential (24 percent), agricultural 

(23 percent), hunt club/private recreational (14 percent), roads 

(2 percent), and commercial (2 percent). The public lands 

include state park, state game, state natural area, and national 

park parcels, much of which are forested, as are hunt club 

parcels. Use of land for seasonal recreation results in seasonal 

increases in population.

Groundwater is the main source of drinking water in the 

county. Individual on-site wells are common in many residential areas, although large wells supply some developments. 

On-site wastewater disposal is common in residential areas; 

sand mounds are more commonly used than septic systems in 

the more recent developments, although some developments 

are sewered and have sewage-treatment systems that discharge 

treated effluent to land areas or to surface water.

For this reconnaissance assessment of groundwater quality in Pike County, 20 wells were sampled in 2007 throughout 

the county to represent groundwater quality in the principal 

land uses and geologic units. The laboratory analyses selected 

for the samples were intended to identify naturally occurring constituents from the aquifer or constituents introduced 

by human activities that pose a health risk or otherwise were 

of concern in groundwater in the county. The samples were 

analyzed for major ions, nutrients, selected trace metals, 

volatile organic compounds (VOCs), selected organic wastewater compounds, gross alpha-particle and gross beta-particle 

activity, uranium, and radon-222. Wells in each of six main 

geologic units (five fractured-rock aquifers and one glacial 

unconsolidated aquifer) and six land-use categories (commercial, high-density residential with on-site wastewater disposal, 

moderate-density residential with on-site wastewater disposal, 

residential in a sewered area, pre-development downgradient 

from a proposed large-scale mixed-use land development, and 

undeveloped) were selected for sampling.

Results of the sampling were compared to established 

USEPA drinking-water standards. No established primary 

drinking-water standard or maximum contaminant level 

(MCL) was exceeded by any constituent analyzed. However, 

radon-222 activities were greater than or equal to the proposed 

MCL of 300 pCi/L in water from 15 (75 percent) of the 20 

wells sampled in Pike County in 2007. Radon-222 did not 

exceed the alternative MCL of 4,000 pCi/L in any groundwater sample. The gross alpha-particle and gross beta-particle 

activities were low and did not indicate potential for elevated 

radioactivity other than radon-222. The dissolved arsenic 

concentration of 3.9 μg/L in one sample was greater than 

the health advisory level of 2 μg/L but less than the MCL of 

10 μg/L.

Concentrations of dissolved iron and dissolved manganese and pH exceeded the recommended or secondary 

maximum contaminant levels (SMCLs). Groundwater samples 

from about half of the 20 wells tended to be slightly acidic 
32 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

(median pH was 6.8), and the pH was equal to or less than the 

SMCL lower limit of 6.5 in 9 (45 percent) of the 20 samples. 

Concentrations of dissolved iron were greater than the SMCL 

of 300 μg/L in 3 (15 percent) of 20 samples, and concentrations of dissolved manganese were greater than the SMCL of 

50 μg/L in 7 (35 percent) of 20 samples. Most concentrations 

of dissolved iron and manganese above the SMCLs of 300 

and 50 μg/L, respectively, were in groundwater samples with 

low dissolved oxygen concentrations (0.2 mg/L or less), which 

indicates geochemical control on these metals. Although not 

elevated above drinking-water standards, higher concentrations of copper and zinc were related to lower pH, suggesting 

dissolution of plumbing or naturally occurring metals in acidic 

well water.

Six samples were analyzed for both dissolved and total 

concentrations of selected metals. Total concentrations commonly were much greater than dissolved concentrations of 

iron, in particular, and to a lesser degree for arsenic, lead, 

and copper. Concentrations of dissolved and total manganese 

were relatively similar. Concentrations above the SMCL of 

300 μg/L may be more widespread in the county for particulate iron than for dissolved iron. Higher concentrations of total 

arsenic and total lead appeared to be associated with higher 

concentrations of total iron, suggesting that arsenic and lead 

may sorb onto iron particulates in groundwater. The total 

arsenic concentration in one of the six samples was greater 

than the health advisory level of 2 μg/L but less than the MCL 

of 10 μg/L. The total manganese concentration of 361 μg/L 

in one sample was greater than the health advisory level of 

300 μg/L for manganese.

About half of the groundwater samples had chloride 

concentrations above the estimated natural background levels 

of about 1 to 5 mg/L, indicating that human activities may 

have influenced groundwater quality. Nitrate concentrations 

were less than the estimated natural background level of less 

than 0.8 mg/L as N in all but two groundwater samples. Boron 

concentrations equal to or greater 20 mg/L were above natural 

background levels and were measured in groundwater from 

six wells with elevated sodium and chloride levels, indicating probable association with septic effluent and (or) road salt 

linked to residential development.

Anthropogenic organic compounds were detected at low 

levels in water from 10 of the 20 wells, indicating human 

activities at the land surface have affected groundwater quality 

to some degree. These compounds included VOCs in three 

groundwater samples and a few organic wastewater compounds in nine groundwater samples. The highest measured 

VOC concentration was 39 μg/L of Freon-11 and indicated 

local groundwater contamination by improper disposal of the 

compound. DEET, an insect repellent, was the most frequently 

detected organic wastewater compound at trace levels.

The relations between groundwater quality and geology 

and land-use factors were investigated. Because of the small 

sample size, comparisons between geologic and land-use factors could not be evaluated with rigorous statistics. The nonstatistical, preliminary review indicated some water-quality 

differences were apparent for different geologic units. Higher 

radon-222 activities generally were measured in water samples 

from wells in the Catskill Formation; the highest activities 

(greater than 2,600 pCi/L) were measured in water from the 

Poplar Gap and Packerton Members, undivided. Radon-222 

activities were lower in water from the Trimmers Rock Formation and the glacial units.

Concentrations of chloride and nitrite plus nitrate as 

nitrogen tended to be greater in water from wells in the commercial and residential areas with on-site wastewater disposal 

than in undeveloped and sewered areas. DEET was detected 

in water from wells in most land-use areas, including undeveloped. Except for the one well sample with the Freon-11 

contamination, VOCs and most other organic wastewater 

compounds detected were in water from wells in commercial 

and residential areas with on-site wastewater disposal. These 

results indicate greater impacts on groundwater quality where 

land use is more intensive.

Stream-monitoring data in watersheds with no point 

discharges were reviewed to assess the relation between 

groundwater quality and surface-water quality. Chloride and 

nitrate concentrations were highest in stream base flow in the 

watershed with the most development (roads and residential 

land use) indicating groundwater quality in that watershed has 

been affected by human activities.

Age-dating of groundwater in samples from three wells 

yielded a range of ages from 6 to 54 years before 2007; the 

younger water was in the glacial aquifer and the older water 

was in the bedrock aquifer. Age-dating can be used to estimate 

susceptibility of groundwater to contamination by human 

activities at or near the land surface—younger water is generally more susceptible to contamination than older water is.

Five of the wells sampled in 2007 were sampled previously at least once since 1982. Comparison of chloride and 

nitrate concentrations in the 2007 samples with previous 

samples showed that concentrations of these constituents 

remained similar through time in some wells but increased up 

to three-fold, especially for chloride, in others. The two wells 

with the largest increases in chloride were in a residential and 

commercial area along the Route 209 corridor.

Overall, based on this reconnaissance study, groundwater 

quality in Pike County is relatively good with no constituents 

exceeding any established primary water-quality standards. 

The low levels of human-made organic compounds detected 

and relatively elevated concentrations of chloride and related 

constituents (boron and nitrate) indicate that human activities have influenced groundwater quality in some parts of the 

county.
Acknowledgments 33

Acknowledgments

The cooperation of the Pike County Conservation District 

(PCCD) and the property owners who permitted the collection of groundwater samples from their wells is gratefully 

acknowledged. Personnel from PCCD were instrumental in 

developing the scope and providing information about potential sampling locations. The assistance of Lindsay Hale and 

Leif Olson of the U.S. Geological Survey in sample collection 

also is greatly appreciated.

References Cited

Barnes, K.K., Kolpin, D.W., Furlong, E.T., Zaugg, S.D., 

Meyer, M.T., and Barber, L.B., 2008, A national reconnaissance of pharmaceuticals and other organic wastewater 

contaminants in the United States—I) Groundwater: Science of the Total Environment, v. 402, p. 192–200.

Berg, T.M., Edmunds, W.E., Geyer, A.R., and others, comps., 

1980, Geologic map of Pennsylvania: Pennsylvania Geological Survey, 4th ser., map 1, scale 1:250,000, 2 sheets.

Busenberg, Eurybiades, and Plummer, L.N, 1992, Use of chlorofluorocarbons (CCl3F and CCl2F2) as hydrologic tracers 

and age-dating tools; The alluvium and terrace system of 

central Oklahoma: Water Resources Research, v. 28, no. 9, 

p. 2257–2283.

Busenberg, Eurybiades, and Plummer, L.N., 2000, Dating 

young ground water with sulfur hexafluoride—Natural 

and anthropogenic sources of sulfur hexafluoride: Water 

Resources Research, v. 36, no. 10, p. 3011–3030.

Busenberg, Eurybiades, Plummer, L.N., Cook, P.G., Solomon, 

D.K., Han, L.F., Gröning, M., and Oster, H., 2006, Chapter 

12 Sampling and analytical methods in International Atomic 

Energy Agency (IAEA), Use of chlorofluorocarbons in 

hydrology—A guidebook: International Atomic Energy 

Agency STI/PUB/1238, p. 199–220.

Davis, D.K., 1989, Groundwater resources of Pike County, 

Pennsylvania: Pennsylvania Geological Survey, 4th ser., 

Water Resource Report 65, 63 p.

Durlin, R.R., and Schaffstall, W.P., 2002, Water resources 

data, Pennsylvania, water year 2001, volume 1. Delaware 

River Basin: U.S. Geological Survey Water-Data Report 

PA-01-1, 615 p.

Focazio, M.J., Kolpin, D.W., Barnes, K.K., Furlong, E.T., 

Meyer, M.T., Zaugg, S.D., Barber, L.B., and Thurman, 

M.E., 2008, A national reconnaissance for pharmaceuticals 

and other organic wastewater contaminants in the United 

States—II) Untreated drinking water sources: Science of 

the Total Environment, v. 402, p. 201–216.

Han, L.F., Groening, M., Plummer, L.N., and Solomon, D.K., 

2006, Chapter 11 Comparison of the CFC technique with 

other techniques 3H, 3H/3He, 85Kr, in International Atomic 

Energy Agency (IAEA), Use of chlorofluorocarbons in 

hydrology—A guidebook: International Atomic Energy 

Agency STI/PUB/1238, p. 191–198.

International Atomic Energy Agency (IAEA), 2006, Use of 

chlorofluorocarbons in hydrology—A Guidebook: International Atomic Energy Agency STI/PUB/1238, 277 p.

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

Zaugg, S.D., Barber, L.B., and Buxton, H.T., 2002, Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999–2000—A national reconnaissance: Environmental Science & Technology, v. 36, 

p. 1202–1211.

Lynch, J.A., Horner, K.S., Grimm, J.W., Boyer, Elizabeth, and 

Carrick, Hunter, 2007a, Atmospheric deposition—Spatial 

and temporal variations in Pennsylvania 2006: University 

Park, Pa., The Pennsylvania State University, Penn State 

Institutes of Energy and the Environment, accessed Feb. 10, 

2009, at http://www.dep.state.pa.us/dep/DEPUTATE/

airwaste/aq/acidrain/report/report/htm

Lynch, J.A., Grimm, J.W., Horner, K.S., Carrick, H.C., and 

Boyer, Elizabeth, 2007b, Mercury deposition in Pennsylvania—2006 status report: University Park, Pa., The 

Pennsylvania State University, Penn State Institutes of 

Energy and the Environment, accessed Feb. 20, 2009, at 

http://www.dep.state.pa.us/dep/DEPUTATE/airwaste/aq/

acidrain/report_hg/report.htm

Miles, C.E., and Whitfield, T.G., 2001, comps., Bedrock geology of Pennsylvania: Pennsylvania Geological Survey, 

4th ser., digital dataset, scale 1:250,000.

Montgomery, Arthur, 1969, The mineralogy of Pennsylvania 

1922–1965: Philadephia, Pa., The Academy of Natural 

Sciences Special Publication no. 9, 104 p.

Nelms, D.L., Harlow, G.E., Jr., Plummer, L.N., and 

Busenberg, Eurybiades, 2003, Aquifer susceptibility in Virginia, 1998–2000: U. S. Geological Survey 

Water-Resources Investigations Report 03-4278, 58 p. 

(http://pubs.usgs.gov/wri/wri034278/)

Pennsylvania Department of Environmental Protection, 

2009, Commonwealth of Pennsylvania 2009 fish consumption public health advisory: Harrisburg, Pa., Commonwealth of Pennsylvania, accessed Feb. 20, 2009, at 

http://www.depweb.state.pa.us/watersupply/cwp/

view.asp?a=1261&q=453946

Pike County Commissioners, 2006, Pike County Comprehensive Plan update: Pike County, Pa., accessed Mar. 20, 

2009, at http://www.pikepa.org/Compplan.htm
34 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Plummer, N.L., and Friedman, L.C., 1999, Tracing and dating young water: U.S. Geological Survey Fact Sheet 

FS-134-99, 4 p.

Plummer, L.N., 2005, Dating of young groundwater, in Aggarwal, P.K., Gat, J.R., and Froehlich, K.F.O., eds., Isotopes 

in the Water Cycle—Past, Present and Future of a Developing Science: Dordrecht, The Netherlands, Springer, 

p. 193–220.

Santella, Nicholas, Ho, D.T., Schlosser, Peter, and Stute, 

Martin, 2008, Widespread elevated atmospheric SF6 mixing ratios in the Northeastern United States—Implications 

for groundwater dating: Journal of Hydrology, v. 349, 

p. 139–146.

Senior, L.A., 1994, Geohydrology of, and nitrogen and chloride in, the glacial aquifer, Milford-Matamoras area, Pike 

County, Pennsylvania: U.S. Geological Survey WaterResources Investigations Report 93-4109, 43 p.

Senior, L.A., and Cinotto, P.J., 2007, Effect of on-site wastewater disposal on quality of ground water and base flow—

A pilot study in Chester County, southeastern Pennsylvania, 

2005: U.S. Geological Survey Scientific Investigations 

Report 2007-1253, 50 p.

Smith, R.L., Bohlke, J.K., Garabedian, S.P., Revesz, K.M., 

and Yoshinari, Tadashi, 2004, Assessing denitrification 

in groundwater using a natural gradient tracer test with 

15N—In situ measurement of a sequential multistep 

reaction: Water Resources Research, v. 40, W07101, 

doi:10.029/2003WR002919.

Stackelberg, P.E., Furlong, E.T., Meyer, M.T., Zaugg, S.D., 

Henderson, A.K., and Reissman, D.B., 2004, Persistence 

of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking-water treatment plant: Science of the Total Environment, v. 329, p. 

99–113.

Tertuliani, J.S., Alvarez, D.A., Furlong, E.T., Meyer, M.T., 

Zaugg, S.D., and Koltun, G.F., 2008, Occurrence of organic 

wastewater compounds in the Tinkers Creek watershed 

and two other tributaries to the Cuyahoga River, Northeast 

Ohio: U.S. Geological Survey Scientific Investigations 

Report 2008–5173, 60 p.

United Nations Environment Programme, 2006, Handbook for 

the Montreal Protocol on substances that deplete the ozone 

layer (7th ed.): Nairobi, Kenya, accessed Feb. 18, 2009, at 

http://ozone.unep.org/Publications/MP_Handbook/

Section_1.1_The_Montreal_Protocol/

U.S. Census Bureau, 2000, United States Census 2000 ranking 

tables for counties—Population in 2000 and population 

change from 1990 to 2000 (PHC-T-4): accessed Mar. 3, 

2009, at http://www.census.gov/population/www/cen2000/

briefs/phc-t4/index.html

U.S. Environmental Protection Agency, 2006, 2006 Edition of 

the drinking water standards and health advisories: U.S. 

Environmental Protection Agency EPA 822-R-06-013.

U.S. Environmental Protection Agency, 2007, Proposed 

radon in drinking water rule: accessed Feb. 18, 2009, at 

http://www.epa.gov/safewater/radon/proposal.html

U.S. Geological Survey, 2009a, Pennsylvania active water 

level network—Pike County: accessed May 15, 2009, at 

http://groundwaterwatch.usgs.gov/StateMaps/PA.html

U.S. Geological Survey, 2009b, The Reston Chlorofluorocarbon Laboratory: Reston, Va., accessed May 12, 2009, at 

http://water.usgs.gov/lab/.

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

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

Geological Survey Techniques of Water-Resources 

Investigations, book 9, chaps. A1-A9, available online at 

http://pubs.water.usgs.gov/twri9A

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

eds., September 1999, Collection of water samples: U.S. 

Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A4, accessed February 7, 2007, at 

http://pubs.water.usgs.gov/twri9A4

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

eds., April 2004, Processing of water samples (version 

2.1): U.S. Geological Survey Techniques of WaterResources Investigations, book 9, chap. A5, accessed 

February 9, 2007, at http://pubs.water.usgs.gov/twri9A5/

(Separate updates for 5.6.1.F, “Wastewater, pharmaceutical, 

and antibiotic compounds).

Zaugg, S.D., and Leiker, T.J., 2006, Review of methods 

performance and improvements for determining wastewater 

compounds (Schedule 1433): U.S. Geological Survey 

National Water Quality Technical Memorandum 2006.01.

Zaugg, S.D., Smith, S.G., Schroeder, M.P., Barber, L.B., and 

Burkhardt, M.R., 2002, Methods of analysis by the U.S. 

Geological Survey National Water Quality Laboratory—

Determination of wastewater compounds by polystyrenedivinylbenzene solid-phase extraction and capillary-column 

gas chromatography/mass spectrometry: U.S. Geological 

Survey Water-Resources Investigations Report 01-4186, 

37 p. (Method ID: O-1433-01)
 35

Table 10. Construction characteristics and location of 20 wells sampled in 2007 in Pike County, Pa.

[NAD 83, North American Datum of 1983; DDMMSS, degrees, minutes, seconds; NAVD 88, North American Vertical Datum of 1988; —, no data; Twp., 

township; Geologic unit: 112KMTC, Kame terrace; 112OTSH, Olean outwash; 341PGPK, Poplar Gap and Packerton Members of Catskill Formation, 

undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 

341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

U.S. 

Geological

Survey

local 

well

number

Site identification 

number

Latitude 

(NAD 83), 

DDMMSS

Longitude 

(NAD 83), 

DDMMSS

Landsurface 

altitude, 

feet 

above 

NAVD 88

Well 

depth, 

feet

Casing 

length, 

feet

Year 

drilled Township Geologic Unit

PI-211 410812074581501 410820 745812 711 450 43 1975 Lehman 341TMRK

PI-288 411700075145801 411658 751457 1,649 151 23 1980 Greene 341PGPK

PI-308 410612074591501 410611 745916 349 108 103 1961 Lehman 112OTSH

PI-380 411500074534001 411500 745340 899 98 20 1979 Delaware 341TMRK

PI-390 412115075031401 412115 750314 1,339 325 42 1980 Blooming Grove 341DLRV

PI-464 412114074431801 412114 744318 429 142 142 1984 Westfall 112OTSH

PI-480 411957074462601 411957 744625 464 213 213 1981 Westfall 112KMTC

PI-524 411849074533901 411848 745335 1,138 380 182 2004 Dingman 341TMSG

PI-550 411538074555601 411538 745557 1,206 250 160 1991 Delaware 341TMSG

PI-551 411006074580101 411005 745803 1,109 250 42 1985 Lehman 341TMSG

PI-552 412141074462301 412140 744625 974 — — — Westfall 341TMRK

PI-553 412303075074301 412303 750744 1,509 610 195 1997 Blooming Grove 341LRBW

PI-554 411452074543601 411451 745437 1,054 238 — — Delaware 341TMRK

PI-555 412009075142901 412009 751431 1,788 380 40 1999 Palmyra 341PGPK

PI-556 411738074505001 411737 745051 718 400 51 1999 Delaware 344MNNG

PI-557 411833074582201 411833 745824 1,432 350 66 1977 Dingman 341LRBW

PI-558 410525075021701 410525 750219 439 300 21 1985 Lehman 344MNNG

PI-559 412920075072201 412920 750723 1,258 400 42 1990 Lackawaxen 341LRBW

PI-561 412506074543901 412506 745441 1,300 250 42 1984 Shohola 341LRBW

PI-562 410731075002701 410730 750028 839 200 40 1977 Lehman 341TMRK
36 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 11. Field measurements and results of laboratory analyses for concentrations of major ions, nutrients, and selected metals and trace elements in groundwater samples from 20 wells in Pike County, Pa., 1982–2007. [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; LSD, land surface datum; gal/min, gal- lons per minute; mm Hg, millimeters of mercury; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L as CaCO3, milligrams per liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; Geologic unit: Glacial units— 112KMTC, Kame terrace; 112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill For- mation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation] U.S. Geo- logical Survey local well number Geologic unit Sample date Time Depth to water level (feet below LSD) (72019) Pump flow rate, instanta- neous (gal/min) (00059) Pump or flow period prior to sampling (minutes) (72004) Barometric pressure (mm Hg) (00025) Dissolved oxygen (mg/L) (00300) Dissolved oxygen (percent of saturation) (00301) pH, water, unfiltered field (standard units) (00400) pH, water, unfiltered lab (standard units) (00403) PI-211 341TMRK 8/27/2007 1400 71.15 5 120 755 0.2 2 7.7 7.8 PI-288 341PGPK 6/2/1982 1615 — — — — — — 5.7 6.2 PI-288 341PGPK 9/6/2007 1200 49.25 15 60 747 10.8 94 6.0 7.8 PI-308 112OTSH 7/16/2001 1200 30.11 2 120 752 7.3 66 6.2 6.5 PI-308 112OTSH 8/30/2007 1600 29.94 5 80 750 9.5 87 6.1 6.5 PI-380 341CSKL 7/27/1982 1515 — — — — — — 7.7 7.7 PI-380 341TMRK 9/5/2007 1400 — 2.5 90 760 .2 2 7.9 7.7 PI-390 341DLRV 10/2/2007 1000 34.70 5 100 740 8.4 76 5.7 6.4 PI-464 112OTSH 10/29/1991 1445 — — — — .2 — 7.3 7.9

PI-464 112OTSH 8/28/2007 1330 17.32 6.4 53 746 .2 2 8.2 8.3PI-480 112KMTC 10/25/1991 1053 — — — — 1.2 — 6.9 8.0PI-480 112KMTC 7/11/2001 1200 86.99 5.9 40 740 3.1 30 7.7 7.7PI-480 112KMTC 9/5/2007 1800 88.24 5 90 761 3.8 34 7.8 7.7PI-524 341TMSG 4/17/2006 1200 — — — — — — — —PI-524 341TMSG 10/1/2007 1400 56.82 6.5 80 750 .1 0 8.3 8.3PI-550 341TMSG 8/27/2007 1730 54.08 5 140 755 5.3 48 6.4 7.1PI-551 341TMSG 8/28/2007 1000 58.28 5 105 746 3.7 34 6.2 6.8PI-552 341TMRK 8/28/2007 1600 65.88 5 85 746 .3 2 7.3 7.6PI-553 341LRBW 8/29/2007 1000 124.35 6.2 140 735 .1 1 7.2 7.6PI-554 341TMRK 8/29/2007 1430 77.82 5 90 746 .7 6 6.0 6.5PI-555 341PGPK 8/30/2007 1000 116.92 8.6 90 724 4.6 40 6.8 7.1PI-556 344MNNG 8/30/2007 1230 54.05 5 190 750 .2 2 7.7 7.8PI-557 341LRBW 9/4/2007 1700 49.80 5 95 730 6.0 55 6.2 6.2PI-558 344MNNG 9/5/2007 1100 16.42 5 120 761 8.6 79 6.5 6.9PI-559 341LRBW 9/12/2007 1100 — 5 130 730 4.8 43 6.8 7.3PI-561 341LRBW 10/2/2007 1500 94.86 5 65 740 2.9 26 6.4 6.6PI-562 341TMRK 10/18/2007 1100 18.06 5 60 760 .2 2 7.3 7.9
 37

Table 11. Field measurements and results of laboratory analyses for concentrations of major ions, nutrients, and selected metals and trace elements in groundwater samples from20 wells in Pike County, Pa., 1982–2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; LSD, land surface datum; gal/min, gallons per minute; mm Hg, millimeters of mercury; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L as CaCO3, milligrams per liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; Geologic unit: Glacial units—112KMTC, Kame terrace; 112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

U.S. Geological

Survey

local well

number

Sample

date

Specific

conductance, wat 

unf lab

(μS/cm at

25 °C) 

(90095)

Specific 

conductance, wat 

unf

(μS/cm at

25 °C) 

(00095)

Temperature,

air

(°C)

(00020)

Temperature,

water

(°C)

(00010)

Hardness, 

water

(mg/L as 

CaCO3) 

(00900)

Calcium 

water,

filtered 

(mg/L) 

(00915)

Magnesium, 

water,

filtered 

(mg/L) 

(00925)

Potassium, 

water,

filtered 

(mg/L) 

(00935)

Sodium 

fraction 

of cations 

(percent) 

(00932)

Sodium, 

water,

filtered 

(mg/L) 

(00930)

PI-211 8/27/2007 282 275 28 12.6 100 27 8.73 0.69 23 14.1

PI-288 6/2/1982 66 72 — 10.0 22 6.8 1.1 .50 14 1.6PI-288 9/6/2007 72 70 25.5 9.2 23 7.38 1.13 .41 20 2.71PI-308 7/16/2001 105 100 — 10.4 32 9.55 1.93 .72 26 5.24PI-308 8/30/2007 102 101 25 11.1 30 8.93 1.83 .73 31 6.24PI-380 7/27/1982 297 305 — 13.0 130 32 11 <.10 — 12PI-380 9/5/2007 353 340 22 11.7 130 33.3 11.3 .20 23 17.8PI-390 10/2/2007 81 79 15 10.9 25 5.47 2.67 .80 25 3.92PI-464 10/29/1991 189 185 — 11.5 84 27 4.1 .50 9 4PI-464 8/28/2007 215 205 29 12.2 90 28.2 4.68 .53 9 4.28PI-480 10/25/1991 311 300 — 10.5 140 47 6.2 .50 8 5.7PI-480 7/11/2001 336 329 — 11.8 140 45.7 6.17 .47 12 9.04PI-480 9/5/2007 363 351 24 10.0 140 46.9 6.31 .55 17 13.2PI-524 4/17/2006 — — — — — — — — — —PI-524 10/1/2007 303 299 15 11.1 62 15.5 5.69 .24 58 39.9PI-550 8/27/2007 100 97 25 10.5 41 10.4 3.73 .28 19 4.42PI-551 8/28/2007 216 206 24 11.1 74 18.1 7.02 .46 21 9.21PI-552 8/28/2007 215 207 25 11.0 89 23.7 7.21 .25 14 6.92PI-553 8/29/2007 98 95 25 11.4 33 8.03 3.1 .63 34 7.8PI-554 8/29/2007 190 185 29 11.2 59 14.5 5.6 .58 29 11.2PI-555 8/30/2007 149 142 25 9.2 70 22.4 3.3 .59 4 1.42PI-556 8/30/2007 216 211 25 11.5 87 24.7 6.18 .21 19 9.32PI-557 9/4/2007 195 185 25 10.9 62 14.2 6.36 .66 29 12PI-558 9/5/2007 93 90 20.5 11.6 36 11 1.98 .39 16 3.07PI-559 9/12/2007 237 231 20 10.6 93 25.3 7.29 .78 14 6.95PI-561 10/2/2007 163 162 20 10.5 67 16.2 6.51 .58 12 4.42PI-562 10/18/2007 149 147 18 11.7 61 14.4 6.08 .30 17 5.59
38 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 11. Field measurements and results of laboratory analyses for concentrations of major ions, nutrients, and selected metals and trace elements in groundwater samples from 20 wells in Pike County, Pa., 1982–2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; LSD, land surface datum; gal/min, gallons per minute; mm Hg, millimeters of mercury; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L as CaCO3, milligrams per liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; Geologic unit: Gla- cial units—112KMTC, Kame terrace; 112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation] U.S. Geo- logical Survey local well number Sample date ANC, wat unf fixed end point, field (mg/L as CaCO3) (00410) ANC, wat unf infl pt titr., field (mg/L as CaCO3) (00419) Chloride, water, filtered (mg/L) (00940) Silica, water, filtered (mg/L as SiO2) (00955) Sulfate water, filtered (mg/L) (00945) Residue water, filtered, sum of con- stituents (mg/L) (70301) Ammonia water, filtered (mg/L as N) (00608) Nitrite + nitrate water filtered (mg/L as N) (00631) Nitrite water, filtered (mg/L as N) (00613) Ortho- phosphate, water, filtered, (mg/L as P) (00671) PI-211 8/27/2007 — 78 26.8 14.2 20 E159 0.059 <.06 0.002 0.011 PI-288 6/2/1982 112 — 3.5 4 9 34 <.010 .55 <.010 .01 PI-288 9/6/2007 — 21 4.44 4.8 6.74 E43 E.010 .56 E.001 .016 PI-308 7/16/2001 — 214 9.3 8.79 12.7 E57 E.02 .13 E.003 <.02 PI-308 8/30/2007 — 17 9.81 9 13.1 E61 <.020 .19 <.002 <.006 PI-380 7/27/1982 1114 — 13 16 16 169 .07 <.100 <.010 .01 PI-380 9/5/2007 — 98 39.9 13.9 10.8 E186 .059 <.06 E.001 .011 PI-390 10/2/2007 — 12 5.42 7 10.8 E46 .027 .63 E.001 .007 PI-464 10/29/1991 64 — 5.6 8.2 29 120 <.010 .72 .47 .04

PI-464 8/28/2007 — 57 5.28 9.1 29.6 E122 <.020 1.19 .47 .055PI-480 10/25/1991 92 — 18 8 42 184 <.010 .22 <.010 <.01PI-480 7/11/2001 — b78 34.4 8.53 26.1 E180 <.04 .54 <.006 <.02PI-480 9/5/2007 — 85 38.1 8.8 26.6 E194 <.020 .52 E.001 E.005PI-524 4/17/2006 — — — — — — — — — —PI-524 10/1/2007 — 114 24.4 10.1 .36 E165 .059 <.04 E.001 .02PI-550 8/27/2007 — 38 2.42 9.2 4.88 E59 E.016 E.05 .002 .011PI-551 8/28/2007 — 47 30.1 7.3 11.7 E114 <.020 .41 <.002 .009PI-552 8/28/2007 — 89 2.62 16.9 15.7 E127 E.016 <.06 <.002 .011PI-553 8/29/2007 — 50 .53 9.1 1.07 E61 <.020 <.06 <.002 .02PI-554 8/29/2007 — 47 22.4 14.1 11.3 E110 E.012 .22 <.002 <.006PI-555 8/30/2007 — 71 .9 6.5 7.61 E87 <.020 .36 <.002 .021PI-556 8/30/2007 — 90 5.2 11.2 14 E126 .063 E.04 .005 .016PI-557 9/4/2007 — 35 21.9 10.3 10.6 E106 <.020 2 <.002 .029PI-558 9/5/2007 — 24 1.56 9.6 14.9 E57 <.020 E.04 E.001 .018PI-559 9/12/2007 — 59 23.6 10.1 11.7 E123 <.020 .32 E.001 .012PI-561 10/2/2007 — 39 10.2 11.7 15.8 E91 <.020 .41 E.001 .015PI-562 10/18/2007 — 57 3.19 16.4 11.7 E93 .025 <.04 <.002 E.004

1ANC determined in laboratory.2ANC deterined on filtered sample.
 39

Table 11. Field measurements and results of laboratory analyses for concentrations of major ions, nutrients, and selected metals and trace elements in groundwater samples from 20 wells in Pike County, Pa., 1982–2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; LSD, land surface datum; gal/min, gallons per minute; mm Hg, millimeters of mercury; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L as CaCO3, milligrams per liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; Geologic unit: Glacial units—112KMTC, Kame terrace; 112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

U.S. Geological

Survey

local well

number

Sample

date

Aluminum, 

water,

filtered 

(μg/L) 

(01106)

Arsenic 

water,

filtered 

(μg/L) 

(01000)

Arsenic 

water,

unfiltered 

(μg/L) 

(01002)

Boron, 

water,

filtered 

(μg/L) 

(01020)

Cadmium 

water,

filtered 

(μg/L) 

(01025)

Chromium, 

water,

filtered 

(μg/L) 

(01030)

Copper, 

water,

filtered 

(μg/L) 

(01040)

Copper, 

water, 

unfiltered 

recoverable

(μg/L) 

(01042)

Iron,

water,

filtered 

(μg/L) 

(01046)

Iron,

water, 

unfiltered 

recoverable

(ug/L) 

(01045)

PI-211 8/27/2007 7.9 0.17 — 20 <0.04 <0.12 <0.40 — <6 —

PI-288 6/2/1982 — — — — — — — — M —PI-288 9/6/2007 E1.4 E.11 — 5 .08 .14 72.2 — 23 —PI-308 7/16/2001 <1.0 <.2 — 10 <.04 <.8 17.3 — 74 —PI-308 8/30/2007 3.8 <.12 — 8.2 <.04 E.06 10.5 — 373 —PI-380 7/27/1982 — — — — — — — — 60 —PI-380 9/5/2007 E1.1 .75 — 28 <.04 <.12 .67 — 13 —PI-390 10/2/2007 7.7 .09 1.7 13 .04 E.07 32.4 23.9 32 4,930PI-464 10/29/1991 — — — — — — — — 10 —PI-464 8/28/2007 1.6 3.5 — 5.4 <.04 <.12 .75 — 14 —PI-480 10/25/1991 — — — — — — — — 16 —PI-480 7/11/2001 <1.0 E.1 — E5 <.04 <.8 1.5 — 14 —PI-480 9/5/2007 E1.2 .12 — 5.3 <.04 E.08 1 — 21 —PI-524 4/17/2006 — — <4.0 — — — — — — —PI-524 10/1/2007 E1.2 .29 — 77 <.04 <.12 <1.0 — 32 —PI-550 8/27/2007 <1.6 .12 1.9 5.3 <.04 <.12 22.4 30.1 24 3,530PI-551 8/28/2007 <1.6 E.10 — 10 <.04 <.12 11.4 — 11 —PI-552 8/28/2007 <1.6 .34 — 8.9 <.04 <.12 <.40 — 67 —PI-553 8/29/2007 <1.6 .69 .92 5.3 <.04 <.12 10.8 8.9 14 1,060PI-554 8/29/2007 1.8 <.12 E.10 20 <.04 <.12 9.2 13 675 6,630PI-555 8/30/2007 <1.6 .31 — 6 <.04 <.12 5.3 — <6 —PI-556 8/30/2007 2.8 .55 .65 33 <.04 <.12 .97 92.2 146 237PI-557 9/4/2007 E1.1 .83 — 20 <.04 <.12 17.1 — <6 —PI-558 9/5/2007 <1.6 <.12 — 8.7 <.04 E.07 25.7 — E4 —PI-559 9/12/2007 <1.6 .65 — 5.3 <.04 <.12 10.3 — <6 —PI-561 10/2/2007 <1.6 .29 — 10 <.04 <.12 20.6 — <8 —PI-562 10/18/2007 <1.6 .55 3.9 7.3 <.04 E.11 4.7 7.1 474 8,760
40 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 11. Field measurements and results of laboratory analyses for concentrations of major ions, nutrients, and selected metals and trace elements in groundwater samples from 20 wells in Pike County, Pa., 1982–2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; LSD, land surface datum; gal/min, gallons per minute; mm Hg, millimeters of mercury; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L as CaCO3, milligrams per liter as calcium carbonate; mg/L as N, milligrams per liter as nitrogen; mg/L as P, milligrams per liter as phosphorus; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; Geologic unit: Gla- cial units—112KMTC, Kame terrace; 112OTSH, Olean outwash; Bedrock units—341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation] U.S. Geo- logical Survey local well number Sample date Lead, water, filtered (μg/L) (01049) Lead, water, unfiltered recoverable (μg/L) (01051) Manganese, water, filtered (μg/L) (01056) Manganese, water, unfiltered recoverable (μg/L) (01055) Mercury water, filtered (μg/L) (71890) Molyb- denum, water, filtered (μg/L) (01060) Nickel, water, filtered (μg/L) (01065) Selenium, water, filtered (μg/L) (01145) Zinc, water, filtered (μg/L) (01090) Hardness (mg/L as CaCO3) (00900) PI-211 8/27/2007 <0.12 — 38.8 — <0.010 E0.1 0.11 <0.08 <6 100 PI-288 6/2/1982 — — M — — — — — — 22 PI-288 9/6/2007 1.6 — .6 — <.010 <.1 .71 .12 73 23 PI-308 7/16/2001 .43 — 5 — — <.2 .71 <.3 2.8 32 PI-308 8/30/2007 .16 — 20.4 — <.010 <.1 .8 .17 <6 30 PI-380 7/27/1982 — — 180 — — — — — — 130 PI-380 9/5/2007 .23 — 114 — <.010 .3 .2 <.08 E4 130 PI-390 10/2/2007 .3 1.4 138 170 <.010 <.2 2 .06 11 25 PI-464 10/29/1991 <1 — 290 — — — — — — 84 PI-464 8/28/2007 <.12 — 267 — <.010 1 .11 1.3 <6 90

PI-480 10/25/1991 <1 — 13 — — — — — — 140PI-480 7/11/2001 .46 — 1.6 — — .3 <.06 .5 1.4 140PI-480 9/5/2007 .42 — 1.8 — <.010 .4 .34 .3 E4 140PI-524 4/17/2006 — — — — — — — — — —PI-524 10/1/2007 <.08 — 20.5 — <.010 .3 <.20 <.04 <4 62PI-550 8/27/2007 <.12 .78 2.2 12.4 <.010 E.1 .63 E.07 <6 41PI-551 8/28/2007 .34 — .3 — <.010 <.1 .25 E.06 E4 74PI-552 8/28/2007 E.09 — 292 — <.010 .4 .09 <.08 <6 89PI-553 8/29/2007 E.09 .34 215 234 <.010 E.1 .13 <.08 <6 33PI-554 8/29/2007 E.09 .68 11.2 13.2 <.010 <.1 .65 <.08 14 59PI-555 8/30/2007 <.12 — 4 — <.010 <.1 .15 .14 <6 70PI-556 8/30/2007 <.12 11.8 248 230 <.010 E.1 2.2 <.08 8 87PI-557 9/4/2007 2.23 — .9 — <.010 .2 2.7 E.06 33 62PI-558 9/5/2007 .89 — 1.7 — <.010 <.1 .72 E.06 10 36PI-559 9/12/2007 .22 — <.2 — <.010 .1 .4 .1 E5 93PI-561 10/2/2007 .92 — E.3 — <.010 <.2 E.19 .28 8 67PI-562 10/18/2007 .15 2.86 199 361 <.010 1.5 <.20 <.04 <4 61
 41

Table 12. Results of laboratory analysis for volatile organic compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; surrog, surrogate; Sch, laboratory schedule, %, percent]

U.S. Geological

Survey

local well

number

Sample 

date

Tetrachloroethene, 

water,

filtered 

(μg/L) 

(34476)

1,1,1-Trichloroethane, 

water, 

unfiltered 

(μg/L) 

(34506)

CFC-113 

water, 

unfiltered 

(μg/L) 

(77652)

1,1-Dichloroethane, 

water, 

unfiltered 

(μg/L) 

(34496)

1,1-Dichloroethene, 

water, 

unfiltered 

(μg/L) 

(34501)

1,2-Dichlorobenzene 

water, 

unfiltered 

(μg/L) 

(34536)

1,2-Dichloroethane, 

water, 

unfiltered 

(μg/L) 

(32103)

1,2-Dichloroethaned4, sur 

Sch2090 

wat unf 

% recvy 

(99832)

1,2-Dichloropropane 

water, 

unfiltered 

(μg/L) 

(34541)

1,3-Dichlorobenzene 

water, 

unfiltered 

(μg/L) 

(34566)

PI-211 8/27/2007 <0.2 <0.1 <0.1 <0.1 <0.1 <0.1 <0.2 109 <0.1 <0.1

PI-288 9/6/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 141 <.1 <.1PI-308 7/16/2001 — <.03 <.06 <.04 <.04 <.03 <.1 77.6 <.03 <.03PI-308 8/30/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 112 <.1 <.1PI-380 9/5/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 134 <.1 <.1PI-390 10/2/2007 <.1 <.1 <.1 <.1 <.1 <.1 <.2 134 <.1 <.1PI-464 8/28/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 109 <.1 <.1PI-480 7/11/2001 — <.03 <.06 <.04 <.04 <.03 <.1 109 <.03 <.03PI-480 9/5/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 141 <.1 <.1PI-524 10/1/2007 <.1 <.1 <.1 <.1 <.1 <.1 <.2 127 <.1 <.1PI-550 8/27/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 127 <.1 <.1PI-551 8/28/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 109 <.1 <.1PI-552 8/28/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 111 <.1 <.1PI-553 8/29/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 110 <.1 <.1PI-554 8/29/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 110 <.1 <.1PI-555 8/30/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 111 <.1 <.1PI-556 8/30/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 110 <.1 <.1PI-557 9/4/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 108 <.1 <.1PI-558 9/5/2007 <.2 <.1 <.1 <.1 <.1 <.1 <.2 132 <.1 <.1PI-559 9/12/2007 <.2 .2 <.1 <.1 <.1 <.1 <.2 118 <.1 <.1PI-561 10/2/2007 <.1 <.1 <.1 <.1 <.1 <.1 <.2 135 <.1 <.1PI-562 10/18/2007 <.1 <.1 <.1 <.1 <.1 <.1 <.2 110 <.1 <.1
42 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 12. Results of laboratory analysis for volatile organic compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; surrog, surrogate; Sch, laboratory schedule, %, percent] U.S. Geo- logical Survey local well number Sample date 1,4-Di- chloro- benzene water, unfiltered 

(μg/L) 

(34571)

14Bromo 

fluorobenzene 

surrog, VOC 

Sch water, 

unfiltered 

% recovery 

(99834)

Benzene 

water,

unfiltered 

(μg/L) 

(34030)

Bromodichloromethane 

water,

unfiltered 

(μg/L) 

(32101)

Tribromomethane 

water,

unfiltered 

(μg/L) 

(32104)

Chlorobenzene 

water,

unfiltered 

(μg/L) 

(34301)

cis1,2-Dichloroethene, 

water,

unfiltered 

(μg/L) 

(77093)

Dibromochloromethane 

water,

unfiltered 

(μg/L) 

(32105)

Dichlorodifluoromethane 

water,

unfiltered 

(μg/L) 

(34668)

Dichloromethane 

water,

unfiltered 

(μg/L) 

(34423)

PI-211 8/27/2007 <0.1 93.4 <0.1 <0.1 <0.2 <0.1 <0.1 <0.2 <0.2 <0.2

PI-288 9/6/2007 <.1 100 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-308 7/16/2001 <.05 93.9 <.04 <.05 <.06 <.03 <.04 <.2 <.27 <.2PI-308 8/30/2007 <.1 91.3 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-380 9/5/2007 <.1 101 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-390 10/2/2007 <.1 71.5 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-464 8/28/2007 <.1 92.1 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-480 7/11/2001 <.05 80.7 <.04 <.05 <.06 <.03 <.04 <.2 <.27 <.2PI-480 9/5/2007 <.1 98.6 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-524 10/1/2007 <.1 71.3 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-550 8/27/2007 <.1 75.6 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-551 8/28/2007 <.1 91.8 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-552 8/28/2007 <.1 91.8 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-553 8/29/2007 <.1 91.2 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-554 8/29/2007 <.1 91.3 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-555 8/30/2007 <.1 91.2 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-556 8/30/2007 <.1 91.1 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-557 9/4/2007 <.1 89.8 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-558 9/5/2007 <.1 99.5 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-559 9/12/2007 <.1 74.7 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-561 10/2/2007 <.1 72 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2PI-562 10/18/2007 <.1 84.2 <.1 <.1 <.2 <.1 <.1 <.2 <.2 <.2
 43

Table 12. Results of laboratory analysis for volatile organic compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; surrog, surrogate; Sch, laboratory schedule, %, percent]

U.S. Geological

Survey

local well

number

Sample

date

Diethyl

ether,

water,

unfiltered 

(μg/L) 

(81576)

Diisopropyl

ether,

water,

unfiltered 

(μg/L) 

(81577)

Ethylbenzene 

water,

unfiltered 

(μg/L) 

(34371)

Methyl

tertpentyl

ether,

water,

unfiltered 

(μg/L) 

(50005)

meta- + 

paraXylene, 

water,

unfiltered 

(μg/L) 

(85795)

oXylene, 

water,

unfiltered 

(μg/L) 

(71135)

Styrene 

water,

unfiltered 

(μg/L) 

(71128)

t-Butyl

ethyl

ether,

water,

unfiltered 

(μg/L) 

(50004)

Methyl 

t-butyl

ether,

water,

unfiltered 

(μg/L) 

(78032)

Tetrachloroethene, 

water,

unfiltered 

(μg/L) 

(34475)

PI-211 8/27/2007 <0.2 <0.2 <0.1 <0.2 <0.2 <0.1 <0.1 <0.1 <0.2 <0.1

PI-288 9/6/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-308 7/16/2001 <.2 <.10 <.03 <.11 <.06 <.04 <.04 <.05 <.2 <.10PI-308 8/30/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-380 9/5/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 .2 <.1PI-390 10/2/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-464 8/28/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-480 7/11/2001 <.2 <.10 <.03 <.11 <.06 <.04 <.04 <.05 <.2 <.10PI-480 9/5/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-524 10/1/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-550 8/27/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-551 8/28/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-552 8/28/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-553 8/29/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-554 8/29/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-555 8/30/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-556 8/30/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-557 9/4/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-558 9/5/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-559 9/12/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-561 10/2/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1PI-562 10/18/2007 <.2 <.2 <.1 <.2 <.2 <.1 <.1 <.1 <.2 <.1
44 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 12. Results of laboratory analysis for volatile organic compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; surrog, surrogate; Sch, laboratory schedule, %, percent] U.S. Geo- logical Survey local well number Sample date Tetra- chloro- methane water, unfiltered

(μg/L)

(32102)

Toluene

water,

unfiltered

(μg/L)

(34010)

Toluene

-d8,

surrog,

Sch2090 water, 

unfiltered

% recovery

(99833)

trans1,2-Dichloroethene,

water,

unfiltered

(μg/L)

(34546)

Trichloroethene,

water,

unfiltered

(μg/L)

(39180)

Trichlorofluoromethane

water,

unfiltered

(μg/L)

(34488)

Trichloromethane

water,

unfiltered

(μg/L)

(32106)

Vinyl

chloride,

water,

unfiltered

(μg/L)

(39175)

PI-211 8/27/2007 <0.2 <0.1 98.3 <0.1 <0.1 <0.2 <0.1 <0.2

PI-288 9/6/2007 <.2 <.1 104 <.1 <.1 <.2 <.1 <.2PI-308 7/16/2001 <.06 <.05 99.2 <.03 <.04 <.09 <.02 <.1PI-308 8/30/2007 <.2 <.1 99 <.1 <.1 <.2 <.1 <.2PI-380 9/5/2007 <.2 <.1 101 <.1 <.1 <.2 <.1 <.2PI-390 10/2/2007 <.2 <.1 96 <.1 <.1 <.2 <.1 <.2PI-464 8/28/2007 <.2 <.1 98.2 <.1 <.1 <.2 <.1 <.2PI-480 7/11/2001 <.06 <.05 94.9 <.03 <.04 <.09 <.02 <.1PI-480 9/5/2007 <.2 <.1 98.9 <.1 <.1 <.2 <.1 <.2PI-524 10/1/2007 <.2 <.1 94.1 <.1 <.1 <.2 <.1 <.2PI-550 8/27/2007 <.2 <.1 89.9 <.1 <.1 <.2 <.1 <.2PI-551 8/28/2007 <.2 <.1 99 <.1 <.1 <.2 <.1 <.2PI-552 8/28/2007 <.2 <.1 98.4 <.1 <.1 <.2 <.1 <.2PI-553 8/29/2007 <.2 <.1 98.4 <.1 <.1 <.2 <.1 <.2PI-554 8/29/2007 <.2 <.1 99 <.1 <.1 <.2 .8 <.2PI-555 8/30/2007 <.2 <.1 99.2 <.1 <.1 <.2 <.1 <.2PI-556 8/30/2007 <.2 <.1 99 <.1 <.1 39 <.1 <.2PI-557 9/4/2007 <.2 <.1 98 <.1 <.1 <.2 <.1 <.2PI-558 9/5/2007 <.2 <.1 102 <.1 <.1 <.2 <.1 <.2PI-559 9/12/2007 <.2 <.1 94.5 <.1 <.1 <.2 <.1 <.2PI-561 10/2/2007 <.2 <.1 93.8 <.1 <.1 <.2 <.1 <.2PI-562 10/18/2007 <.2 <.1 99 <.1 <.1 <.2 <.1 <.2
 45

Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent]

U.S. Geological

Survey

local well

number

Sample 

date

1,4-Dichlorobenzene 

water,

filtered 

(μg/L) 

(34572)

-1 Methylnaphthalene, 

water,

filtered 

(μg/L) 

(62054)

2,6-Dimethylnaphthalene, 

water,

filtered 

(μg/L) 

(62055)

-2 Methylnaphthalene, 

water,

filtered 

(μg/L) 

(62056)

3-betaCoprostanol,

water,

filtered 

(μg/L) 

(62057)

-3 Methyl1H-indole, 

water,

filtered 

(μg/L) 

(62058)

3-tertButyl-4-

hydroxyanisole 

water,

filtered 

(μg/L) 

(62059)

-4 Cumylphenol, 

water,

filtered 

(μg/L) 

(62060)

4-n-Octylphenol, 

water,

filtered 

(μg/L) 

(62061)

-4 Nonylphenol,

all isomers, 

water,

filtered 

(μg/L) 

(62085)

PI-211 8/27/2007 <0.1 <0.1 <0.2 <0.1 <2 <0.08 <0.6 <0.14 <2 <5

PI-288 9/6/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-308 7/16/2001 — — — — — — — — — —PI-308 8/30/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-380 9/5/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-390 10/2/2007 <.1 <.1 <.1 <.1 <1 <.08 <.6 <.1 <1 <5PI-464 8/28/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-480 7/11/2001 — — — — — — — — — —PI-480 9/5/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-524 10/1/2007 <.1 <.1 <.1 <.1 <1 <.08 <.6 <.1 <1 <5PI-550 8/27/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-551 8/28/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-552 8/28/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-553 8/29/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-554 8/29/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-555 8/30/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-556 8/30/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-557 9/4/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-558 9/5/2007 <.1 <.1 <.2 <.1 <2 <.08 <.6 <.14 <2 <5PI-559 9/12/2007 <.1 <.1 <.2 <.1 <2 <.08 — <.14 <2 <5PI-561 10/2/2007 <.1 <.1 <.1 <.1 <1 <.08 <.6 <.1 <1 <5PI-562 10/18/2007 <.1 <.1 <.1 <.1 <1 <.08 <.6 <.1 <1 <5
46 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent] U.S. Geo- logical Survey local well number Sample date 4-Nonyl phenol di- ethox- ylate, water, filtered 

(μg/L) 

(62083)

4t-Octylphenol

diethoxylate, 

water,

filtered 

(μg/L) 

(61705)

4t-Octylphenol 

monoethoxylate, 

water,

filtered 

(μg/L) 

(61706)

4-tertOctylphenol, 

water,

filtered 

(μg/L) 

(62062)

5-Methyl1Hbenzotriazole, 

water,

filtered 

(μg/L) 

(62063)

9,10-Anthraquinone 

water,

filtered 

(μg/L) 

(62066)

Acetophenone, 

water,

filtered 

(μg/L) 

(62064)

AHTN,

water,

filtered 

(μg/L) 

(62065)

Anthracene,

water,

filtered 

(μg/L) 

(34221)

Benzo-[a]-

pyrene, 

water,

filtered 

(μg/L) 

(34248)

PI-211 8/27/2007 <1 <1 <1 <0.10 <2 <0.2 <0.1 <0.5 <0.1 <0.1

PI-288 9/6/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-308 7/16/2001

—

—

—

—

—

—

—

—

—

—

PI-308 8/30/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-380 9/5/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-390 10/2/2007 <1 <1 <1 <1 <.08 <.2 <.1 <.5 <.1 <.1PI-464 8/28/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-480 7/11/2001

—

—

—

—

—

—

—

—

—

—

PI-480 9/5/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-524 10/1/2007 <1 <1 <1 <1 <.08 <.2 <.1 <.5 <.1 <.1PI-550 8/27/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-551 8/28/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-552 8/28/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-553 8/29/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-554 8/29/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-555 8/30/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-556 8/30/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-557 9/4/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-558 9/5/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-559 9/12/2007 <1 <1 <1 <.10 <2 <.2 <.1 <.5 <.1 <.1PI-561 10/2/2007 <1 <1 <1 <1 <.08 <.2 <.1 <.5 <.1 <.1PI-562 10/18/2007 <1 <1 <1 <1 <.08 <.2 <.1 <.5 <.1 <.1
 47

Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent]

U.S. Geological

Survey

local well

number

Sample

date

Benzophenone 

water,

filtered 

(μg/L) 

(62067)

beta-Sitosterol,

water,

filtered 

(μg/L) 

(62068)

beta-Stigmas

tanol,

water,

filtered 

(μg/L) 

(62086)

Bisphenol A,

water,

filtered 

(μg/L) 

(62069)

Bisphenol 

A-d3 surrog, 

Sch 2033 & 

8033, water, 

filtered

% recovery 

(99583)

Bromacil, 

water,

filtered 

(μg/L) 

(04029)

Caffeine, 

water,

filtered 

(μg/L) 

(50305)

Caffeine13C, surrog, 

wat flt percent recovry 

(99959)

Caffeine-13C 

sur Sch 2033 

& 8033, wat 

flt % recvy 

(99584)

Camphor 

water,

filtered 

(μg/L) 

(62070)

PI-211 8/27/2007 <0.2 <2 <2 — 5.4 <0.4 <0.2 — 92.3 <0.1

PI-288 9/6/2007 <.2 <2 <2 — 0 <.4 <.2 — 88.2 <.1PI-308 7/16/2001 — — — — — <.03 <.010 108 — —PI-308 8/30/2007 <.2 <2 <2 M 7.9 <.4 <.2 — 84.8 <.1PI-380 9/5/2007 <.2 <2 <2 — 4.1 <.4 <.2 — 80.4 <.1PI-390 10/2/2007 <.1 <2 <1 — 0 <.4 <.1 — 89.7 <.1PI-464 8/28/2007 <.2 <2 <2 — 3.9 <.4 <.2 — 87.2 <.1PI-480 7/11/2001 — — — — — <.03 <.010 100 — —PI-480 9/5/2007 <.2 <2 <2 — 0 <.4 <.2 — 81.3 <.1PI-524 10/1/2007 <.1 <2 <1 — 0 <.4 <.1 — 95 <.1PI-550 8/27/2007 <.2 <2 <2 — 0 <.4 <.2 — 91.3 <.1PI-551 8/28/2007 <.2 <2 <2 — 4.3 <.4 <.2 — 85 <.1PI-552 8/28/2007 <.2 <2 <2 — 13.6 <.4 <.2 — 84.9 <.1PI-553 8/29/2007 <.2 <2 <2 — 0 <.4 <.2 — 82.5 <.1PI-554 8/29/2007 <.2 <2 <2 — E4.8 <.4 <.2 — 83.5 <.1PI-555 8/30/2007 <.2 <2 <2 — 0 <.4 <.2 — 44.9 <.1PI-556 8/30/2007 <.2 <2 <2 — 0 <.4 <.2 — 88.9 <.1PI-557 9/4/2007 <.2 <2 <2 — 0 <.4 <.2 — 74 <.1PI-558 9/5/2007 <.2 <2 <2 — 0 <.4 <.2 — 83 <.1PI-559 9/12/2007 <.2 <2 <2 — 0 <.4 <.2 — 83.4 <.1PI-561 10/2/2007 <.1 <2 <1 — 0 <.4 <.1 — 88.3 <.1PI-562 10/18/2007 <.1 <2 <1 — 2.9 <.4 <.1 — 84.2 <.1
48 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent] U.S. Geo- logical Survey local well number Sample date Carbaryl, water, fltrd 0.7u GF (μg/L) (82680) Carbazole, water, filtered 

(μg/L) 

(62071)

Chlorpyrifos 

water,

filtered 

(μg/L) 

(38933)

Cholesterol,

water,

filtered 

(μg/L) 

(62072)

Cotinine, 

water,

filtered 

(μg/L) 

(62005)

DecaFbiphenl

surrog,

Sch 2033 & 

8033, water, 

filtered

% recovery 

(99585)

DEET,

water,

filtered 

(μg/L) 

(62082)

Diazinon, 

water,

filtered 

(μg/L) 

(39572)

D-Limonene,

water,

filtered 

(μg/L) 

(62073)

Fluoranthene, 

water,

filtered 

(μg/L) 

(34377)

PI-211 8/27/2007 <1 <0.1 <0.2 <1 <0.400 63.7 <0.2 <0.2 <0.1 <0.1

PI-288 9/6/2007 <1 <.1 <.2 <1 <.400 59.7 <.2 <.2 <.1 <.1PI-308 7/16/2001 <.041

— <.005

—

—

—

— <.005

—

—

PI-308 8/30/2007 <1 <.1 <.2 <1 <.400 61.9

M <.2 <.1 <.1

PI-380 9/5/2007 <1 <.1 <.2 <1 <.400 55 <.2 <.2 <.1 <.1PI-390 10/2/2007 <1 <.1 <.1 <1 <.400 53.7 <.1 <.1 <.04 <.1PI-464 8/28/2007 <1 <.1 <.2 <1 <.400 54.8

M <.2 <.1 <.1

PI-480 7/11/2001 <.041

— <.005

—

—

—

— <.005

—

—

PI-480 9/5/2007 <1 <.1 <.2 <1 <.400 54.5

M <.2 <.1 <.1

PI-524 10/1/2007 <1 <.1 <.1 <1 <.400 44.9 <.1 <.1 <.04 <.1PI-550 8/27/2007 <1 <.1 <.2 <1 <.400 67.2 <.2 <.2 <.1 <.1PI-551 8/28/2007 <1 <.1 <.2 <1 <.400 49.4

M <.2 <.1 <.1

PI-552 8/28/2007 <1 <.1 <.2 <1 <.400 53.9

M <.2 <.1 <.1

PI-553 8/29/2007 <1 <.1 <.2 <1 <.400 61.4 <.2 <.2 <.1 <.1PI-554 8/29/2007 <1 <.1 <.2 <1 <.400 64.4

M <.2 <.1 <.1

PI-555 8/30/2007 <1 <.1 <.2 <1 <.400 49.8 .2 <.2 <.1 <.1PI-556 8/30/2007 <1 <.1 <.2 <1 <.400 63.4

M <.2 <.1 <.1

PI-557 9/4/2007 <1 <.1 <.2 <1 <.400 50.9

M <.2 <.1 <.1

PI-558 9/5/2007 <1 <.1 <.2 <1 <.400 55 <.2 <.2 <.1 <.1PI-559 9/12/2007 <1 <.1 <.2 <1 <.400 56.2 <.2 <.2 <.1 <.1PI-561 10/2/2007 <1 <.1 <.1 <1 <.400 50.2 <.1 <.1 <.04 <.1PI-562 10/18/2007 <1 <.1 <.1 <1 <.400 53.8 <.1 <.1 <.04 <.1
 49

Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent]

U.S. Geological

Survey

local well

number

Sample

date

Fluorathene 

-d10, surrog,

Sch 20/8033 

water,

filtered

% recovery 

(99586)

HHCB, 

water,

filtered 

(μg/L) 

(62075)

Indole, 

water,

filtered 

(μg/L) 

(62076)

Isoborneol, 

water,

filtered 

(μg/L) 

(62077)

Isophorone 

water,

filtered 

(μg/L) 

(34409)

Isopropylbenzene 

water,

filtered 

(μg/L) 

(62078)

Isoquinoline,

water,

filtered 

(μg/L) 

(62079)

Menthol 

water,

filtered 

(μg/L) 

(62080)

Metalaxyl,

water,

filtered 

(μg/L) 

(50359)

Methyl 

salicylate, 

water,

filtered 

(μg/L) 

(62081)

PI-211 8/27/2007 88.2 <0.5 <0.1 <0.1 <0.1 <0.1 <0.4 <0.2 <0.2 <0.2

PI-288 9/6/2007 81.4 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-308 7/16/2001 — — — — — — — — <.02 —PI-308 8/30/2007 84.9 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-380 9/5/2007 77.3 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-390 10/2/2007 90 <.5 <.1 <.1 <.1 <.1 <.2 <.2 <.1 <.1PI-464 8/28/2007 85 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-480 7/11/2001 — — — — — — — — <.02 —PI-480 9/5/2007 76.8 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-524 10/1/2007 93.5 <.5 <.1 <.1 <.1 <.1 <.2 <.2 <.1 <.1PI-550 8/27/2007 88.9 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-551 8/28/2007 81 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-552 8/28/2007 80.2 E.1 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-553 8/29/2007 83.8 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-554 8/29/2007 79.7 M <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-555 8/30/2007 87.9 M <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-556 8/30/2007 89.2 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-557 9/4/2007 70 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-558 9/5/2007 77.6 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-559 9/12/2007 90.5 <.5 <.1 <.1 <.1 <.1 <.4 <.2 <.2 <.2PI-561 10/2/2007 91.9 <.5 <.1 <.1 <.1 <.1 <.2 <.2 <.1 <.1PI-562 10/18/2007 85 <.5 <.1 <.1 <.1 <.1 <.2 <.2 <.1 <.1
50 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007 Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued [Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent] U.S. Geo- logical Survey local well number Sample date Metola- chlor, water, filtered (μg/L) (39415) Naphth- alene, water, filtered (μg/L) (34443) p- Cresol, water, filtered (μg/L) (62084) Phenan- threne, water, filtered (μg/L) (34462) Phenol, water, filtered (μg/L) (34466) Prome- ton, water, filtered (μg/L) (04037) Pyrene, water, filtered (μg/L) (34470) Tri- bromo- methane water, filtered (μg/L) (34288) Tri- butyl phos- phate, water, filtered (μg/L) (62089) Triclo- san, water, filtered (μg/L) (62090) PI-211 8/27/2007 <0.2 <0.1 <0.18 <0.1 <0.4 <0.4 <0.1 <0.1 <0.2 <0.2 PI-288 9/6/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2 PI-308 7/16/2001 <.013

—

—

—

— <.01

—

—

—

—

PI-308 8/30/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-380 9/5/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-390 10/2/2007 <.1 <.1 <.18 <.1 <.2 <.2 <.1 <.1 <.2 <.2PI-464 8/28/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-480 7/11/2001 <.013

—

—

—

— <.01

—

—

—

—

PI-480 9/5/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-524 10/1/2007 <.1 <.1 <.18 <.1 <.2 <.2 <.1 <.1 <.2 <.2PI-550 8/27/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-551 8/28/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-552 8/28/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1

M <.2

PI-553 8/29/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-554 8/29/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-555 8/30/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-556 8/30/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-557 9/4/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-558 9/5/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-559 9/12/2007 <.2 <.1 <.18 <.1 <.4 <.4 <.1 <.1 <.2 <.2PI-561 10/2/2007 <.1 <.1 <.18 <.1 <.2 <.2 <.1 <.1 <.2 <.2PI-562 10/18/2007 <.1 <.1 <.18 <.1 <.2 <.2 <.1 <.1 <.2 <.2
 51

Table 13. Results of laboratory analysis for organic wastewater compounds in groundwater samples from 20 wells in Pike County, Pa., 2001 and 2007.—Continued[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific constituent; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value below method reporting level; M, measured but not quantified below method reporting level; DEET, N,N-diethyl-meta-toluamide; HHCB, hexahydrohexamethyl cyclopentabenzopyran; AHTN, acetyl hexamethyl tetrahydro napthalene; surrog, surrogate; Sch, laboratory schedule; %, percent]

U.S. Geological

Survey

local well

number

Sample

date

Triethyl citrate 

water,

filtered

(μg/L) 

(62091)

Triphenyl 

phosphate, 

water,

filtered

(μg/L) 

(62092)

Tris(2-

butoxyethyl)

phosphate,

water,

filtered

(μg/L) 

(62093)

Tris(2-

chloroethyl)

phosphate, 

water,

filtered

(μg/L)

(62087)

Tris(di 

chloroi-Pr)

phosphate,

water,

filtered

(μg/L) 

(62088)

PI-211 8/27/2007 <0.4 E0.1 <0.5 <0.2 <0.2

PI-288 9/6/2007 <.4 <.2 <.5 <.2 <.2PI-308 7/16/2001 — — — — —PI-308 8/30/2007 <.4 <.2 <.5 <.2 <.2PI-380 9/5/2007 <.4 <.2 <.5 <.2 <.2PI-390 10/2/2007 <.2 <.1 <.4 <.1 <.1PI-464 8/28/2007 <.4 <.2 <.5 <.2 <.2PI-480 7/11/2001 — — — — —PI-480 9/5/2007 <.4 <.2 <.5 <.2 <.2PI-524 10/1/2007 <.2 <.1 <.4 <.1 <.1PI-550 8/27/2007 <.4 <.2 <.5 <.2 <.2PI-551 8/28/2007 <.4 <.2 <.5 <.2 <.2PI-552 8/28/2007 <.4 <.2 E.1 <.2 <.2PI-553 8/29/2007 <.4 <.2 <.5 <.2 <.2PI-554 8/29/2007 <.4 <.2 <.5 <.2 <.2PI-555 8/30/2007 <.4 <.2 <.5 <.2 <.2PI-556 8/30/2007 <.4 <.2 <.5 <.2 <.2PI-557 9/4/2007 <.4 <.2 <.5 <.2 <.2PI-558 9/5/2007 <.4 <.2 <.5 <.2 <.2PI-559 9/12/2007 <.4 <.2 <.5 <.2 <.2PI-561 10/2/2007 <.2 <.1 <.4 <.1 <.1PI-562 10/18/2007 <.2 <.1 <.4 <.1 <.1
52 Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

Table 14. Results of laboratory analysis for radionuclide activities in water from 20 wells in Pike County, Pa., 2001 and 2007.

[Value in parentheses is the parameter code–a 5-digit number used in the U.S. Geological Survey computerized data system to uniquely identify a specific 

constituent; pCi/L, picocuries per liter; μg/L, micrograms per liter; —, no data; <, less than; E, estimated value; R, radchem no detect; 2-sigma, uncertainty at 

two standard deviations; Th-230, thorium-230; Cs-137, cesium-137; Rn-222, radon-222; alpha, alpha-particle; beta, beta-particle; Geologic unit: 112KMTC, 

Kame terrace; 112OTSH, Olean outwash; 341PGPK, Poplar Gap and Packerton Members of Catskill Formation, undivided; 341DLRV, Delaware River Member of Catskill Formation; 341LRBW, Long Run and Walcksville Members of Catskill Formation, undivided; 341TMSG Towamensing Member of the Catskill 

Formation; 341TMRK, Trimmers Rock Formation; 344MNNG, Mahantango Formation]

U.S. Geological

Survey

local well

number

Geologic 

unit

Sample 

date

Alpha 

radioactivity

30 day,

water 

filtered

Th-230, 

(pCi/L) 

(62639)

Alpha 

radioactivity

72 day,

water 

filtered

Th-230, 

(pCi/L) 

(62636)

Beta

radioactivity

30 day,

water 

filtered

Cs-137, 

(pCi/L) 

(62645)

Beta

radioactivity

30 day,

water 

filtered

Cs-137, 

(pCi/L) 

(62642)

Rn-222 

2-sigma 

water, 

unfiltered 

(pCi/L) 

(76002)

Rn-222,

water,

unfiltered 

(pCi/L) 

(82303)

Uranium 

natural 

water,

filtered

(μg/L) 

(22703)

PI-211 341TMRK 8/27/2007 R-.2 R.0 R-.1 R.5 17 90 0.04

PI-288 341PGPK 9/6/2007 R.1 R-.4 R.6 R.4 46 2,650 .05

PI-308 112OTSH 7/16/2001 — — — — 28 820 <.02

PI-308 112OTSH 8/30/2007 R-.7 R-.6 R.2 1.1 20 490 <.04

PI-380 341TMRK 9/5/2007 R-2.4 R-1.2 R-.4 R.3 17 190 .1

PI-390 341DLRV 10/2/2007 R-.8 R.4 2.2 R-.1 27 730 .03

PI-464 112OTSH 8/28/2007 R.3 R.2 1.2 1.4 19 230 .59

PI-480 112KMTC 7/11/2001 — — — — 24 500 .15

PI-480 112KMTC 9/5/2007 R-1.6 R-.3 .6 R.5 21 470 .17

PI-524 341TMSG 10/1/2007 R-.1 R-1.0 R.9 .9 23 470 .22

PI-550 341TMSG 8/27/2007 R.1 R.4 R.4 R-1.9 46 2,460 .05

PI-551 341TMSG 8/28/2007 R-.3 R.1 R.1 R-.4 46 2,650 <.04

PI-552 341TMRK 8/28/2007 R-.2 1.0 R.4 R.5 17 150 .21

PI-553 341LRBW 8/29/2007 R-2.0 R.2 2.4 R.2 21 300 E.04

PI-554 341TMRK 8/29/2007 R.6 R-.7 R.1 R.1 34 1,150 <.04

PI-555 341PGPK 8/30/2007 R.5 1.3 1.4 .9 45 2,430 .33

PI-556 344MNNG 8/30/2007 R.1 2.0 R-.4 R.1 21 330 .13

PI-557 341LRBW 9/4/2007 R-.8 R-.5 .9 .9 37 1,700 .25

PI-558 344MNNG 9/5/2007 R-.3 R-.3 R.6 R-.5 37 1,730 <.04

PI-559 341LRBW 9/12/2007 R.5 R.6 R.8 R.4 43 1,880 1.15

PI-561 341LRBW 10/2/2007 R-.9 R.0 R.1 R.2 42 2,020 .05

PI-562 341TMRK 10/18/2007 R-.2 R.5 1.0 R.6 17 150 .28
 53

Table 15. Dissolved gas data used to calculate excess air and recharge temperature for CFC and SF6 age-dating and measured 

concentrations of CFC and SF6 gases in groundwater samples collected from four wells in Pike County, Pa., in 2007.

[N2, nitrogen; Ar, argon; O2, oxygen; CO2, carbon dioxide; CH4, methane, SF6, sulfur hexafluoride; trichlorotrifluorothane; CFC-11, trichlorofluoromethane; 

CFC-12, dichlorodifluoromethane; CFC-113, trichlorotrifluorothane; —, no data; °C, degrees Celsius; mg/L, milligrams per liter; mm Hg, millimeters mercury, 

BP, barometric pressure; cc, cubic centimeters; STP, standard temperature and pressure; pmol/kg, picomol per kilogram; fmol/kg, fentomol per kilogram; pptv, 

parts per trillion by volume; contam., contaminated, sample could not be analyzed]

Sample 

name

Date Time

Field

temperature

(°C)

Salinity

Recharge 

elevation 

(feet)

N2

(mg/L)

Ar

(mg/L)

O2

(mg/L)

CO2

(mg/L)

CH4

(mg/L)

PI-308 8/30/2007 1600 11.13 0.00 350 23.469 0.812 8.44 19.87 0.000

PI-308 8/30/2007 1600 11.13 .00 350 22.894 .803 8.22 20.10 .000

PI-553 8/29/2007 1000 11.45 .00 1,510 22.866 .793 .28 5.13 .000

PI-553 8/29/2007 1000 11.45 .00 1,510 22.701 .790 .31 5.16 .000

PI-555 8/30/2007 1000 9.21 .00 1,790 19.911 .727 4.43 14.77 .001

PI-555 8/30/2007 1000 9.21 .00 1,790 20.055 .730 4.64 14.60 .001

PI-556 8/30/2007 1230 11.51 .00 660 22.419 .781 .61 3.41 .003

PI-556 8/30/2007 1230 11.51 .00 660 — — — — —

Sample 

name

Date Time mm Hg cc from cc from Delta Recharge Excess Air

BP N2 Ar cc T °C cc STP/L

PI-308 8/30/2007 1600 750.3 3.918 3.918 0.000 6.1 3.9

PI-308 8/30/2007 1600 750.3 3.309 3.309 .000 6.0 3.3

PI-553 8/29/2007 1000 719.0 3.751 3.751 .000 5.2 3.8

PI-553 8/29/2007 1000 719.0 3.593 3.593 .000 5.2 3.6

PI-555 8/30/2007 1000 711.6 1.514 1.514 .000 6.4 1.5

PI-555 8/30/2007 1000 711.6 1.630 1.630 .000 6.3 1.6

PI-556 8/30/2007 1230 741.8 3.443 3.443 .000 6.9 3.4

PI-556 8/30/2007 1230 741.8 — — — — —

Sample 

name

Date Time

Corrected CFC concentrations

CFC-12 

(pmol/kg)

CFC-11 

(pmol/kg)

CFC-113 

(pmol/kg)

PI-308 08/30/07 1600 4.191 9.059 0.548

PI-308 08/30/07 1600 4.146 9.319 .547

PI-553 08/29/07 1000 .109 .201 .008

PI-553 08/29/07 1000 .104 .171 .007

PI-555 08/30/07 1000 1.638 2.497 .234

PI-555 08/30/07 1000 1.697 2.439 .228

PI-556 08/30/07 1230 16.812 contam. contam.

Sample 

name

Date Time SF6

(fmol/kg)

Calculated 

SF6 (pptv) 

partial 

pressure

PI-308 08/30/07 1600 3.173 5.130

PI-308 second bottle broken

PI-553 08/29/07 1000 .134 .213

PI-553 08/29/07 1000 .128 .208

PI-555 08/30/07 1000 1.288 2.601

PI-555 08/30/07 1000 1.316 2.624

PI-556 08/30/07 1230 16.683 111.354

PI-556 08/30/07 1230 16.964 111.831

1

Laboratory indicated possible contamination for well PI-556.


Senior—Groundwater-Quality Assessment, Pike Couty, Pennsylvania, 2007—Scientific Investigations Report 2009–5129