U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2014–3042

May 2014

Arsenic, Iron, Lead, Manganese, and Uranium 

Concentrations in Private Bedrock Wells in 

Southeastern New Hampshire, 2012–2013

Printed on recycled paper

Major Findings:

• Nearly 3 out of 10 (28 percent) water samples from 232 private bedrock wells tested in southeastern New Hampshire contained trace-metal 

concentrations that exceed one or more of the following standards: the U.S. Environmental Protection Agency’s (EPA) maximum contaminant 

levels in public water supplies of 10 micrograms per liter (μg/L) for arsenic and 30 μg/L for uranium, the EPA action level of 15 μg/L for lead, and 

the EPA lifetime health advisory level of 300 μg/L for manganese.

• Whereas 92 percent of the study participants reported that they drink their well water, only 34 percent of those reported some type of 

treatment—and the most common reported systems were for the removal of iron and (or) manganese.

• As of 2010, estimates of the numbers of residents in the study area that may have private wells in bedrock aquifers that supply waters with 

trace-metal concentrations exceeding standards are: arsenic exceeding 10 μg/L, 49,700 people; lead exceeding 15 μg/L, 8,600 people; uranium 

exceeding 30 μg/L, 7,500 people; and manganese exceeding 300 μg/L, 14,900 people.

Introduction

Trace metals, such as arsenic, iron, lead, 

manganese, and uranium, in groundwater used 

for drinking have long been a concern because 

of the potential adverse effects on human 

health and the aesthetic or nuisance problems 

that some present. Moderate to high concentrations of the trace metal arsenic have been 

identified in drinking water from groundwater 

sources in southeastern New Hampshire, a 

rapidly growing region of the State (Montgomery and others, 2003). During the past 

decade (2000–10), southeastern New Hampshire, which is composed of Hillsborough, 

Rockingham, and Strafford Counties (fig. 1), 

has grown in population by nearly 48,700 (or 

6.4 percent) to 819,100. These three counties 

contain 62 percent of the State’s population 

but encompass only about 22 percent of the 

land area (New Hampshire Office of Energy 

and Planning, 2011). According to a 2005 

water-use study (Hayes and Horn, 2009), 

about 39 percent of the population in these 

three counties in southeastern New Hampshire uses private wells as sources of drinking 

water, and these wells are not required by the 

State to be routinely tested for trace metals or 

other contaminants.

Some trace metals have associated 

human-health benchmarks or nonhealth 

guidelines that have been established by the 

U.S. Environmental Protection Agency (EPA) 

Weare

Derry

Strafford

Hollis

Deerfield

Milton

Antrim

Lee

Dover Barrington

Rochester

Candia

Nottingham

Bedford

Wilton

Amherst

Nashua

Salem

Auburn

Deering

Hudson

Milford

Epping

Goffstown

Hillsborough

Hancock New

Boston

Mason Pelham

New

Durham

London-

 derry

Chester

Rye

Farmington

Merrimack

Durham

Exeter

Raymond

Temple

Manchester

Windham

 Peterborough

Northwood

 New

Ipswich

Greenfield Kingston

Frances-

 town

Sharon

Brook-

 line

 Lyndeborough

Fremont

Middleton

Litchfield

StraBrent- tham

wood

San- Hampton

down Danville

Portsmouth

Madbury

Atkinson

Mont

Vernon

Newton

Green-

 land

Plaistow

Newmarket

Newington

Kensington

Windsor

Bennington

Seabrook

North

Hampton

Hampton Falls

Somersworth

Newfields

Rollinsford

Greenville

South Hampton

Hampstead

East Kingston

New

Castle

71°

72°

43°

43°20'

0 5 10 MILES

0 5 10 KILOMETERS

0 50 MILES

0 50 KILOMETERS

Study

area

NEW

HAMPSHIRE

Town boundary

EXPLANATION

County

Hillsborough

Rockingham

Strafford

Town boundaries from U.S. Geological Survey

Digital data, 1968−88, 1:24,000;

Albers Equal-Area Conic projection

Standard parallels 29°30'N and 45°30'N, central meridian 71°00'W MAINE

MASSACHUSETTS

VERMONT

Figure 1. Locations of towns in Hillsborough, Rockingham, and Strafford counties in the 

southeastern New Hampshire study area.
to regulate public water supplies. The EPA 

has established a maximum contaminant level 

(MCL) of 10 micrograms per liter (μg/L) 

for arsenic (As) and a MCL of 30 μg/L for 

uranium (U) because of associated health 

risks (U.S. Environmental Protection Agency, 

2012). Iron (Fe) and manganese (Mn) are 

essential for human health, but Mn at high 

doses may have adverse cognitive effects in 

children (Bouchard and others, 2011; Agency 

for Toxic Substances and Disease Registry, 

2012); therefore, the EPA has issued a lifetime 

health advisory (LHA) of 300 μg/L for Mn. 

Recommended secondary maximum contaminant levels (SMCLs) for Fe (300 μg/L) 

and Mn (50 μg/L) were established primarily 

as nonhealth guidelines—based on aesthetic 

considerations, such as taste or the staining 

of laundry and plumbing fixtures—because 

these contaminants, at the SMCLs, are not 

considered to present risks to human health. 

Because lead (Pb) contamination of drinking water typically results from corrosion of 

plumbing materials belonging to water-system 

customers but still poses a risk to human 

health, the EPA established an action level 

(AL) of 15 μg/L for Pb instead of an MCL 

or SMCL (U.S. Environmental Protection 

Agency, 2012). The 15-μg/L AL for Pb has 

been adopted by the New Hampshire Department of Environmental Services for public 

water systems, and if exceeded, the public 

water system must inform their customers 

and undertake additional actions to control 

corrosion in the pipes of the distribution 

system (New Hampshire Department of 

Environmental Services, 2013).

Unlike the quality of drinking water 

provided by public water suppliers, the quality 

of drinking water obtained from private wells 

in New Hampshire is not regulated; consequently, private wells are sampled only when 

individual well owners voluntarily choose to 

sample them. The U.S. Geological Survey 

(USGS), in cooperation with the EPA New 

England, conducted an assessment in 2012–13 

to provide private well owners and State and 

Federal health officials with information on 

the distribution of trace-metal (As, Fe, Pb, 

Mn, and U) concentrations in groundwater 

from bedrock aquifers in the three counties 

of southeastern New Hampshire (fig. 1). This 

fact sheet analyzes data from water samples 

collected by a randomly selected group of 

private well owners from the three-county 

study area and describes the major findings 

for trace-metal concentrations.

Sampling Strategy

A database maintained by the New 

Hampshire Department of Environmental 

Services containing information on private 

bedrock wells was used to randomly select 

wells from within the three-county study area 

(New Hampshire Department of Environmental Services, 2010). Sampling instructions and 

sample bottles were mailed to well owners 

who agreed to participate in this study. Samples were obtained from 232 participants—

approximately 30 percent of all the well 

owners who received a letter requesting their 

participation. About 143 of the participants 

from this study also participated in a previous 

arsenic study (Montgomery and others, 2003). 

Each study participant in the current study 

was asked to collect a raw-water sample from 

a location within the home prior to any treatment. Most of the samples (60 percent) were 

collected from a kitchen faucet, 16.5 percent 

were collected from an outside spigot, 15 

percent from a spigot off the pressure tank, 

and 8.5 percent from a bathroom faucet or 

other location. The samples were acidified 

with ultrapure nitric acid by USGS personnel 

and then submitted to the EPA New England 

Regional Laboratory in Chelmsford, Massachusetts, for analysis according to EPA 

method 200.8 (U.S. Environmental Protection 

Agency, 1994). The minimum reporting levels 

for the studied trace metals are listed in table 

1. A quality-assurance project plan was developed to assure the quality of the data obtained 

from this study. Forty-two quality-control 

(QC) samples represented 15 percent of the 

total samples received and included duplicate, 

field-blank, and standard reference samples. 

Online access to the environmental and QC 

sample results is available at: http://pubs.usgs.

gov/fs/2014/3042/. Results from the analysis 

of the QC samples indicated no contamination 

issues or measurable bias.

The Range of Trace-Metal 

Concentrations

Arsenic concentrations in 232 groundwater samples received ranged from less than 

(<) 1 to 140 μg/L; Fe concentrations ranged 

from <55 to 16,000 μg/L; Pb concentrations 

ranged from <0.2 to 290 μg/L; Mn concentrations ranged from <0.5 μg/L to 1,700 μg/L; 

and U concentrations ranged from <1 to 

270 μg/L (table 1). Arsenic, Pb, and Mn 

were detected in more than 50 percent of the 

samples, and U was detected in 49.1 percent 

of the samples (table 1). Iron was detected in 

the fewest number of samples (40.5 percent), 

probably as a result of its high minimum 

reporting level of 55 μg/L (table 1). The 

analytical results show, on the basis of humanhealth benchmarks and nonhealth guidelines, 

What is the Difference Between Milligrams per Liter and Micrograms 

per Liter?

In this fact sheet, metal concentrations are reported in micrograms per liter. Another 

common reporting level is milligrams per liter. A concentration of 1 milligram per liter (mg/L) 

is equivalent to 1,000 μg/L. Because most metals are usually detected at concentrations below 

1 mg/L, the use of the μg/L reporting level allows a laboratory to report many results as whole 

numbers instead of mixed numbers in which “0.0” precedes the significant digits. The EPA 

and State health agencies generally use milligrams per liter in their literature on drinkingwater standards. For example, the EPA MCL of arsenic is 0.010 mg/L, which is equivalent 

to 10 μg/L.

Table 1. Summary of arsenic, iron, manganese, lead, and uranium concentrations in 

groundwater samples from private bedrock wells in southeastern New Hampshire, 2012–13.

[Water samples were collected by the study participants from untreated sources in the home. No., number; MRL, 

minimum reporting level; μg/L, micrograms per liter; Min, minimum; Max, maximum; As, arsenic; Fe, iron; Mn, 

manganese; Pb, lead; U, uranium; <, less than]

Trace metal

Number 

of 

samples

MRL,

in μg/L

Percent of 

samples 

equal to or 

exceeding the 

MRL

Concentration, in μg/L

Min Median Max

Total arsenic (as As) 232 1 57.3 <1 1.6 140

Total iron (as Fe) 232 55 40.5 <55 <55 16,000

Total manganese (as Mn) 232 0.5 87.5 <0.5 10.5 1,700

Total lead (as Pb) 232 0.2 64.2 <0.2 0.36 290

Total uranium (as U) 232 1 49.1 <1 <1 270
that concentrations of As in 40 samples (17.2 

percent) exceeded the MCL of 10 μg/L, 

concentrations of U in 6 samples (2.6 percent) 

exceeded the MCL of 30 μg/L, concentrations 

of Mn in 12 samples (5.2 percent) exceeded 

the LHA of 300 μg/L, concentrations of Mn in 

62 samples (26.7 percent) exceeded the SMCL 

of 50 μg/L, and concentrations of Fe in 39 

samples (16.8 percent) exceeded the SMCL of 

300 μg/L (table 2). Seven samples (3 percent) 

had Pb concentrations that exceeded the EPA 

AL of 15 μg/L. Overall, 28 percent of the 

wells had concentrations of As, Mn, Pb, or U 

that exceeded a human-health benchmark or 

nonhealth guideline.

Trace-Metal Occurrence in 

Relation to Geology

There were distinct spatial patterns of 

trace-metal concentrations greater than their 

respective human-health benchmarks or nonhealth guidelines within the study area (fig. 2). 

Data were analyzed in relation to mapped 

bedrock geologic units (referred to hereafter 

as “geologic units”) identified on the State 

geologic map of New Hampshire (Lyons and 

others, 1997). Geologic units are rock types 

that have unique characteristics and, thus, are 

defined on the basis of factors such as mineral 

composition, age, and processes of rock formation. Trace-metal (As, Fe, Mn, and U) data 

from the groundwater samples were grouped 

according to the geologic units in which the 

sampled wells were located. The Pb data were 

not analyzed in relation to the geologic units 

because materials used for the construction of 

wells, pumps, spigots, and water-distribution 

lines can have components that contain leachable amounts of Pb. These manmade materials 

are possible sources of the Pb detected in the 

water samples.

Out of 35 geologic units within 

the three-county study area, 21 geologic 

units were represented by at least one 

groundwater sample. Two geologic units 

had only 1 sample, 10 geologic units had 

2 to 9 samples, and 9 geologic units had 10 

or more samples (table 2). The 21 geologic 

units were further grouped into three bedrock 

categories (felsic igneous, mafic igneous, 

metasedimentary) based on similarities among 

the characteristics of the geologic units (table 

2). The percentage of wells in each geologic 

unit with trace-metal concentrations exceeding human-health benchmarks or nonhealth 

guidelines was computed, and then geologic 

units were grouped together into selected 

percentage ranges, as shown in figure 2.

 Results of this analysis indicate that 

the geologic units and bedrock categories 

were markedly different in terms of As, Fe, 

Mn, and U concentrations that exceeded 

human-health benchmarks and (or) nonhealth 

guidelines (table 2). None of the samples from 

wells in the Massabesic Gneiss Complex or 

Gray biotite granite had concentrations of 

As that exceeded 10 μg/L, yet these geologic 

units had the largest percentages (8.7 and 

11.1 percent, respectively) of samples with 

concentrations of U that exceeded 30 μg/L. 

In contrast, 30.3 percent of the samples 

from wells in the Spaulding Tonalite had As 

concentrations that exceeded 10 μg/L, but 

none of the samples had U concentrations 

that exceeded 30 μg/L. The felsic igneous, 

mafic igneous, and metasedimentary bedrock 

categories each had at least one geologic unit 

in which 20 percent or more of the samples 

had concentrations of As that exceeded 

10 μg/L. Samples with high U (greater than 

30 μg/L) were primarily from wells in three 

geologic units that are part of the felsic igneous bedrock category (table 2). The largest 

U concentration (270 μg/L) was in a water 

sample from a well in the Two-mica granite 

of northern and southeastern New Hampshire. 

The largest As concentration (140 μg/L) was 

in a water sample from a well in the Spaulding Tonalite.

Similar geologic units can have markedly different percentages of samples with 

As concentrations exceeding the MCL of 

10 μg/L. For example, 11.6 percent of the 

water samples from wells in the Berwick 

Formation had concentrations of As exceeding 

the MCL, whereas 22.2 percent of the water 

samples from wells in the Berwick Formation, unnamed member, had As concentrations 

exceeding the MCL (table 2). The main difference between the two geologic units is that 

the Berwick Formation, unnamed member, 

contains more calc-silicate minerals than the 

Berwick Formation (Lyons and others, 1997). 

The study done by Montgomery and others 

(2003) had similar findings.

High concentrations of Fe and Mn 

occurred throughout the study area (fig. 2). 

However, geologic units in which more than 

30 percent of water samples had Fe and Mn 

concentrations exceeding their respective 

SMCLs (50 μg/L for Mn and 300 μg/L for 

Fe) were predominantly from the metasedimentary bedrock category. Only samples from 

wells in the Concord Granite, a member of the 

felsic igneous bedrock category, had similarly 

high percentages of Mn (53.9 percent) and 

Fe (30.8 percent) concentrations exceeding 

SMCLs (table 2).

Water Treatment

More than 92 percent of the study 

participants reported that they use the water 

from their private wells as drinking water, 

and 34 percent of those participants who use 

their wells for drinking reported some type 

of water-treatment system. Water softeners 

(44 participants) and sediment filters (25 participants) were the most commonly reported 

treatment systems. Only four participants specifically reported treating for As; none for U 

or Pb. The most common complaints reported 

by the participants were about problems with 

Fe and Mn. Therefore, it is not surprising that 

a greater percentage of wells with high Fe 

and (or) Mn concentrations—above SMCLs 

at which these metals cause staining and taste 

problems—have a treatment system than other 

wells do (table 3). Among wells with As or 

U concentrations above the MCL, there is 

no significant difference between the wells 

that have a treatment system and those that 

do not (table 3). This insignificant difference 

indicates that owners of private bedrock wells 

are more likely to treat their well water for 

contaminants that can be seen or tasted, such 

as Fe and Mn, than for invisible and tasteless 

contaminants, such as U or As.

Human Health Implications

High concentrations of As and U in 

drinking water have been associated with 

adverse health outcomes, primarily cancers, and currently are regulated by Federal 

standards for public water supplies (U.S. 

Environmental Protection Agency, 2012). 

New research also has shown that children 

exposed to high concentrations of Mn in 

drinking water may be at risk for cognitive 

problems (Bouchard and others, 2011). Potential health effects from long-term exposure to 

Pb concentrations above the AL could delay 

physical and mental development in infants 

and children, cause children to show slight 

deficits in attention span and learning ability, 

and cause kidney problems and high blood 

pressure in adults (U.S. Environmental Protection Agency, 2012). Unlike the other trace 

metals described, Fe ingested from drinking 

water is not directly associated with adverse 

health effects.

In this section, an estimate of the 

number of people with private wells with 

high As, U, Pb, and Mn concentrations is 

presented. According to the most current U.S. 

Census Bureau data (New Hampshire Office 

of Energy and Planning, 2011), approximately 

319,000 people in 2010 obtained drinking 

water from private wells in the three-county 

study area. Recent well data from the State of 
Table 2. Summary of the percentages of water samples with arsenic, iron, manganese, and uranium concentrations exceeding humanhealth benchmarks and nonhealth guidelines, by geologic unit, from private bedrock wells in southeastern New Hampshire, 2012–2013.

[Geologic units are from Lyons and others (1997). Major bedrock categories are described in detail in Flanagan and others (2012). Color shadings indicate the percentage of wells with exceedances above concentration thresholds in ranges of <1 percent , 1 to 10 percent , >10 to 20 percent , >20 to 30 percent , and 

>30 percent . MCL, enforceable U.S. Environmental Protection Agency (EPA) maximum contaminant level for public water systems; LHA, EPA lifetime health 

advisory level determined using EPA toxicity data and methods; SMCL, EPA secondary maximum contaminant level; >, greater than; <, less than]

Geologic unit 

Number 

of 

samples

Human-health benchmark Nonhealth guideline

Percent of 

study area 

underlain 

by geologic 

unit2

MCL MCL LHA SMCL SMCL

Percent of water samples with concentrations 

(in micrograms per liter) of:

 

Uranium Arsenic Manganese Manganese Iron

 >30 >10 >300 >50 >300

Felsic igneous bedrock

Mesoperthitic biotite granite1 3 0 0 0 0 0 1

Kinsman Granodiorite 20 0 20 5 20 20 8

Massabesic Gneiss Complex 23 8.7 0 0 21.7 4.4 10

Spaulding Tonalite 33 0 30.3 3 27.3 15.2 10

Concord Granite 13 7.7 7.7 15.4 53.9 30.8 7

Gray biotite granite 9 11.1 0 0 0 0 3

Two-mica granite of northern and southeastern New 

Hampshire1

2 50 50 0 0 0 2

Mafic igneous bedrock

Exeter Diorite 10 0 50 0 10 20 3

Metasedimentary bedrock

Berwick Formation 43 2.3 11.6 4.7 20.9 11.6 16

Berwick Formation, unnamed member 19 0 22.2 0 21.1 10.5 6

Eliot Formation 9 0 22.2 11.1 33.3 22.2 <1

Kittery Formation 6 0 16.7 0 16.7 0 3

Rangely Formation, pink to green calc-silicate and purple 

biotite granofels1

1 0 0 0 100 0 <1

Littleton Formation1 2 0 50 0 50 0 2

Perry Mountain Formation 8 0 12.5 0 37.5 25 6

Rangely Formation, undivided1 2 0 0 0 0 50 <1

Rangely Formation, lower part 11 0 18.2 18.2 45.5 45.5 4

Rangely Formation, upper part 10 0 20 10 60 40 5

Rye Complex1 3 0 0 33.3 33.3 33.3 2

Smalls Falls Formation, undivided 4 0 25 0 25 0 1

Madrid Formation1 1 0 0 100 100 100 <1

Overall for the study area 232 2.6 17.2 5.2 26.7 16.8

1

Water-quality results from three or fewer samples do not necessarily represent the actual groundwater-quality conditions of wells in this geologic unit.

2

Six percent of the three-county study area was underlain by 14 individual geologic units from which no water samples were received.

New Hampshire indicate that about 90 percent 

of the State’s rural residents obtain their drinking water from bedrock wells (New Hampshire Department of Environmental Services, 

2010). By using these U.S. Census Bureau 

and State of New Hampshire data and the percentages of human-health benchmark exceedances for the three-county study area (table 2), 

it can be estimated that in the study area 

49,700 people and 7,500 people, respectively, 

obtain their drinking water from bedrock 

wells with As concentrations greater than the 

MCL of 10 μg/L and U concentrations greater 

than the MCL of 30 μg/L. About 8,600 people 

may have drinking water from bedrock wells 

with Pb concentrations greater than the AL of 

15 μg/L, and more than 14,900 people may 

have drinking water with Mn concentrations 

that exceed the LHA of 300 μg/L. For individual households, the likelihood of having high 

As, U, or Mn concentrations depends in part 

on the location of the household’s well within 

a particular geologic unit. The likelihood of 

having high Pb concentrations might depend 

more on the geochemical conditions of the 

groundwater (such as low pH) and the condition of the components used in the plumbing 

system within the individual household.
EXPLANATION

Iron, in micrograms 

 per liter

< 55

55 to 300

> 300

43°20’ 

D. Iron

 Percent of wells, by grouped geologic units, with iron 

 greater than 300 micrograms per liter

72°

71°

43°

EXPLANATION

Arsenic, in micrograms 

 per liter

< 1

1 to 10

> 10

A. Arsenic

 Percentage of wells, by grouped geologic units, with arsenic 

 greater than 10 micrograms per liter

72°

71°

43°

43° 20’ 

0 10 20 MILES 5

0 20 KILOMETERS 10

Town boundaries from U.S. Geological Survey, Digital data, 1968−88,1:24,000;

Geologic units digitized from Lyons and others, 1997, 1:250,000;

Albers Equal-Area Conic projection, Standard parallels 29°30'N and 45°30'N, central meridian 71°W

Uranium, in micrograms 

 per liter

< 1

1 to 30

> 30

EXPLANATION

43°20’ 

B. Uranium

 Percent of wells, by grouped geologic units, with uranium

 greater than 30 micrograms per liter

72°

71°

43°

Manganese, in micrograms 

 per liter

< 1

1 to 50

> 50 to 300

> 300

EXPLANATION

72°

71°

43°

C. Manganese

 Percent of wells, by grouped geologic units, with manganese

 greater than 50 micrograms per liter

43°20’ 

NOTE: Individual geologic unit boundaries within a group are not shown. White areas

within maps indicate geologic units from which no samples were received

EXPLANATION

Geologic units grouped by range of percentages of wells in which trace 

metals exceed concentration thresholds: 

Less than 1

1 to 10

Greater than 10 to 20

Greater than 20 to 30

Greater than 30

Town boundary

Figure 2. Geologic units in Hillsborough, Rockingham, and Strafford counties in southeastern New Hampshire, grouped by range of 

percentages of private bedrock wells in which trace metals exceed concentration thresholds for A, arsenic, B, uranium, C, manganese, and 

D, iron. Concentrations of trace metals in water samples collected from individual wells and the spatial distribution of the wells are also 

shown. For information on the individual geologic units in each group, see table 2. See Lyons and others (1997) for the location of individual 

geologic units. <, less than; > greater than.
Table 3. Comparison of trace-metal concentrations in untreated water samples between 

nontreated and treated private bedrock wells in southeastern New Hampshire, 2012–13.

[μg/L, micrograms per liter; n, number; > greater than]

Water-quality criteria 

(concentrations are 

in μg/L)

Percent of all wells 

in study (n = 232)

Is well water treated?1

Percent of wells

No (n=151) Yes (n=79)

Arsenic > 10 17.2 17.2 16.5

Iron > 300 16.8 8 34.2

Manganese > 50 26.7 18.5 43

Lead > 15 3 1.3 6.3

Uranium > 30 2.6 3.3 1.3

1

Information on treatment systems is not known at two wells.

For additional information, contact

Office Chief, New Hampshire-Vermont Office

U.S. Geological Survey 

New England Water Science Center

331 Commerce Way, Suite 2

Pembroke, NH 03275

(603) 226-7800; dc_nh@usgs.gov

http://nh.water.usgs.gov/

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20143042

The data for this study are available in appendixes 1 through 5, which are available at: http://pubs.usgs.gov/fs/2014/3042

Water Testing and Treatment 

Guidelines:

NHDES Drinking Water and Groundwater 

Bureau, (603)-271-2513; 

email at dwgbinfo@des.nh.gov 

http://des.nh.gov/organization/divisions/water/

dwgb/well_testing/index.htm

Acknowledgments

The authors thank the citizens who 

participated in the study and the staff and 

contractors at the EPA New England Regional 

Laboratory in Chelmsford, Massachusetts, 

including Dan Boudreau, Doris Guzman, 

and Mike Dowling, for sample analysis. 

This study was done in cooperation with 

the Regional Applied Research Effort 

program of the EPA Office of Research 

and Development (ORD). The authors also 

thank Randall Ross (EPA ORD) for project 

review and coordination and Eliza Gross and 

Jonas Casey-Williams for their technical and 

editorial reviews, which greatly enhanced the 

quality of the manuscript.

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By Sarah M. Flanagan1

 , Marcel Belaval2, 

and Joseph D. Ayotte1

1

U.S. Geological Survey 

2

U.S. Environmental Protection Agency