U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2018–1071

Prepared in cooperation with the City of Chicago, Department of Water Management; City of East Chicago, 

Utilities Department; Indiana Department of Environmental Management, Drinking Water Branch; National 

Institutes of Health/National Institute of Environmental Health Sciences (NIH/NIEHS); University of Illinois at 

Chicago, School of Public Health

Concentrations of Lead and Other Inorganic Constituents 

in Samples of Raw Intake and Treated Drinking Water 

From the Municipal Water Filtration Plant and Residential 

Tapwater in Chicago, Illinois, and East Chicago, Indiana, 

July–December 2017

Concentrations of Lead and Other Inorganic 

Constituents in Samples of Raw Intake and 

Treated Drinking Water From the Municipal 

Water Filtration Plant and Residential 

Tapwater in Chicago, Illinois, and 

East Chicago, Indiana, July–December 2017

By Kristin M. Romanok,Dana W. Kolpin,Shannon M. Meppelink, 

Michael J. Focazio,Maria Argos, Mary E. Hollingsworth, R. Blaine McCleskey,

Andrea R. Putz, Alan Stark, Christopher P. Weis, Abderrahman Zehraoui, and 

Paul M. Bradley

Prepared in cooperation with the City of Chicago, Department of Water 

Management; City of East Chicago, Utilities Department; Indiana Department of 

Environmental Management, Drinking Water Branch; National Institutes of Health/

National Institute of Environmental Health Sciences (NIH/NIEHS); University of 

Illinois at Chicago, School of Public Health

Open-File Report 2018–1071

U.S. Department of the Interior

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

RYAN K. ZINKE, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2018

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

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

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

Suggested citation:

Romanok, K.M., Kolpin, D.W., Meppelink, S.M., Focazio, M.J., Argos, M., Hollingsworth, M.E., McCleskey, R.B., 

Putz, A.R., Stark, A., Weis, C.P., Zehraoui, A., and Bradley, P.M., 2018, Concentrations of lead and other inorganic 

constituents in samples of raw intake and treated drinking water from the municipal water filtration plant and 

residential tapwater in Chicago, Illinois, and East Chicago, Indiana, July–December 2017: U.S. Geological Survey 

Open-File Report 2018–1071, 10 p., https://doi.org/10.3133/ofr20181071.

ISSN 2331-1258 (online)
iii

Contents

Acknowledgments........................................................................................................................................iv

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

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

Background............................................................................................................................................3

Purpose and Scope ..............................................................................................................................3

Methods...........................................................................................................................................................3

Sampling Site Selection.......................................................................................................................3

Sampling Methods................................................................................................................................4

Analytical Methods...............................................................................................................................7

National Water Quality Laboratory ...........................................................................................7

Redox Chemistry Laboratory .....................................................................................................7

Quality Assurance/Quality Control............................................................................................7

Results .............................................................................................................................................................7

Chicago and East Chicago Water Filtration Plant Sampling..........................................................8

Chicago Area Tapwater Sampling .....................................................................................................8

Discussion.......................................................................................................................................................8

EPA Guidance on Reducing Pb Exposure in Home Drinking Water......................................................9

References Cited............................................................................................................................................9

Figure

1. Diagram showing a typical water distribution system from untreated source water, 

through water filtration plant to treated residential tap water, with and without pointof-use filtration device.................................................................................................................2

Tables

1. Concentration results of lead analyzed by the U.S. Geological Survey, National Water 

Quality Laboratory, Denver, Colorado, and Redox Chemistry Laboratory, Boulder, 

Colorado, for the U.S. Geological Survey Environmental Health Mission Area, Water 

and Wastewater Infrastructure Project, Tapwater Study, Chicago, Illinois, and 

East Chicago, Indiana, July–December, 2017 ..........................................................................5

2. Maximum concentrations of trace elements detected in tapwater in the U.S. Geological 

Survey Environmental Health Mission Area, Water and Wastewater Infrastructure 

Project, Tapwater Study, Chicago, Illinois, and East Chicago, Indiana,

July–December, 2017 ...................................................................................................................8
iv

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 2.590 square kilometer (km2) 

Volume

ounce, fluid (fl. oz) 0.02957 liter (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.

Data

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

Supplemental Information

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).

Conversion Factors

Acknowledgments

The authors extend appreciation to Miguel Del Toral, Peggy Donnelly, and Kimberly Harris with 

the U.S. Environmental Protection Agency, Region 5. 

We also acknowledge the assistance of Paul Buszka, David Lampe, and Cheryl Silcox (retired) with 

the U.S. Geological Survey Ohio-Kentucky-Indiana Water Science Center, and Celeste Journey and 

Kelly Smalling for providing colleague reviews.
1

U.S. Geological Survey.

2

University of Illinois.

3

Indiana Department of Environmental Management.

4

Chicago Department of Water Management.

5

National Institutes of Health/NIEHS.

6

East Chicago Utilities Department.

Concentrations of Lead and Other Inorganic Constituents 

in Samples of Raw Intake and Treated Drinking Water 

From the Municipal Water Filtration Plant and Residential 

Tapwater in Chicago, Illinois, and East Chicago, Indiana, 

July–December 2017

By Kristin M. Romanok,1 Dana W. Kolpin,1 Shannon M. Meppelink,1 Michael J. Focazio,1 Maria Argos,2

Mary E. Hollingsworth,3 R. Blaine McCleskey,1 Andrea R. Putz,4 Alan Stark,4 Christopher P. Weis,5

Abderrahman Zehraoui,6 and Paul M. Bradley1

Abstract

The U.S. Geological Survey (USGS) Environmental 

Health Mission Area (EHMA) is providing comprehensive 

science on sources, movement, and transformation of contaminants and pathogens in watershed and aquifer drinking-water 

supplies and in built water and wastewater infrastructure 

(referred to as the USGS Water and Wastewater Infrastructure 

project) in the Greater Chicago Area and elsewhere in the 

United States, to fill data gaps identified by stakeholders and 

collaborators in drinking water and public health. EHMA 

Water and Wastewater Infrastructure research specifically 

provides insight into natural factors in the environment as well 

as those water-infrastructure components and processes (such 

as source-water corrosivity, treatment, plumbing, and so forth) 

that might influence human exposure to chemical and microbial contaminants at the residential tap. This infrastructureexposure research role is fulfilled uniquely by the USGS and 

not by the U.S. Environmental Protection Agency (EPA), 

other agencies, or municipalities that focus on regulatory and 

policy activities and related compliance. The USGS approach 

to assessing the possible links between human health and 

chemical contaminant and pathogen exposure in drinking 

water is conducted in collaboration with public health experts 

and includes comprehensive characterization of the presence/

absence and concentrations of more than 500 organic and 27 

inorganic chemical constituents at the point of use (tap). 

Laboratory results for lead and other inorganic contaminants in Chicago, Illinois, and East Chicago, Indiana, residential 

tapwater are being released to ensure the timely release of 

quality-assured data to participants in the study. Concentrations 

of lead and other inorganic constituents were assessed in 

drinking water at the point of use (kitchen tap or filter) in 45 

residential locations and in two locations within each of the two 

Chicago water purification plants and the two East Chicago 

water filtration plants during July–December 2017. Three 

methods were used for analyzing lead. The most sensitive 

method had a reporting limit of 0.020 micrograms per liter 

(μg/L). When using the most sensitive analytical method, lead 

was detected in 39 of 45 residential tapwater samples, with 

concentrations ranging from less than 0.020 μg/L to 5.31 μg/L 

(median of the detected values = 0.481 μg/L). Concentrations 

of lead also were detected in Lake Michigan intake water at 

all water purification/filtration plant facilities at concentrations 

ranging from 0.083 to 0.330 μg/L, but were not detected above 

the reporting limit in any samples of treated, pre-distribution 

drinking water at any of the water purification/filtration 

plant facilities.

Because the USGS Water and Wastewater Infrastructure 

project in the Greater Chicago Area is focused on the 

potential human exposure to a broad suite of organic and 

inorganic contaminants in drinking water and is not focused 

specifically on lead, the sampling protocol did not include 

“first-draw,” stagnant sampling and samples were collected 

with point-of-use treatment in place, if present. Thus, the lead 

results reported herein are not appropriate for assessment 

of compliance with the EPA 1991 Lead and Copper Rule.

Information resources for lead mitigation and water filtration 

are provided. 
2 Lead and Inorganic Constituents in Water From the Filtration Plant and Tapwater in Chicago, Ill., and East Chicago, Ind.

Figure 1. Typical water distribution system from untreated source water, through water filtration plant (WFP) to treated 

residential tap water, with and without point-of-use (POU) filtration device.

Introduction

Population growth, increased urbanization, complex 

environmental contaminant mixtures, and aging water-supply 

infrastructure have raised public concerns about the quality 

and long-term sustainability of drinking water across the 

United States. For decades, the U.S. Geological Survey 

(USGS) has assessed the quantity and quality of the Nation’s 

ambient groundwater and surface-water drinking-water 

supplies (https://www.usgs.gov/science/mission-areas). 

To help address the public’s concerns about water quality 

and to provide regulatory and public health agencies 

the scientific context for managing human-health risks 

associated with exposure to contaminants in drinking water, 

the USGS Environmental Health Mission Area (EHMA, 

https://www2.usgs.gov/envirohealth/) has initiated water and 

wastewater infrastructure research. The focus of the research 

is on (1) assessing point-of-use (tapwater) drinking-water 

exposure pathways for a broad range of potential environmental contaminants and (2) exploring infrastructure-related 

factors that could alter or transform chemical constituents or 

microbial communities in drinking water (such as treatment 

plant technology, distribution system characteristics, private 

plumbing components, and point-of-use treatment) (fig. 1). 

The USGS EHMA is collaborating with the University 

of Illinois at Chicago (UIC) School of Public Health and 

the National Institutes of Health/National Institute of 

Environmental Health Sciences (NIH/NIEHS) to assess the 

quality and potential human-health concerns of residential 

tapwater in the Greater Chicago area, including in the city 

of East Chicago, Indiana. The USGS EHMA is focusing 

on developing comprehensive datasets that document the 

presence and (or) absence and concentrations of more than 

500 organic and 27 inorganic chemical constituents as well 

as conducting analyses to determine the presence of bacterial 

community composition in tapwater to provide insights into 

infrastructure-related factors that might influence contaminant 

exposures at the point of use. These datasets are scoped 

and collected in collaboration with UIC and NIH/NIEHS 

to explore associations between contaminant exposures in 

drinking water and human health. The overall project objective 

is to characterize the occurrence of a broad range of possible 

organic and inorganic constituents in tapwater and possible 

links to human health. Lead (Pb) contamination of tapwater is 

a concern for residents of Chicago, Illinois, and East Chicago, 

Indiana, because of the existence of legacy lead service lines 

in both public and private (curb to tap premise plumbing) 

segments of the municipal drinking-water distribution 

systems, the documented occurrence of low orthophosphate 

levels in the drinking-water system, the documented industrial 

lead contamination of surface soils and ongoing Superfund 

assessment and mitigation in East Chicago, and concerns 

that active remediation of soil contamination may alter the 

structural integrity and biochemical quality of the drinkingwater supply in East Chicago (EPA, 2018d). Thus, the timely 

release of quality-assured data on concentrations of Pb and 

other inorganic constituents in tapwater samples collected 

as part of the EHMA’s Water and Wastewater Infrastructure 

Project’s Greater Chicago Area investigation is an important 

part of the EHMA’s Tapwater Exposure Study.
Methods 3

Background

The U.S. Environmental Protection Agency (EPA) has 

established human-health regulations and guidelines for 

inorganic drinking-water constituents under the National 

Primary Drinking Water Regulations (NPDWR) (EPA, 2018c) 

and the Lead and Copper Rule (LCR) of 1991 (EPA, 2008, 

2018a). These standards include Maximum Contaminant 

Level (MCL), Maximum Contaminant Level Goal (MCLG), 

and Treatment Technique Action Level (TTAL) concentration 

standards to limit contaminants in public drinking water. 

Compliance monitoring in regard to these standards is based 

on established EPA sample-collection methods (EPA, 2016). 

In the current report, reference to these standards is for 

comparison purposes only. 

 The TTAL for Pb is 15 micrograms per liter (μg/L) 

(additional information available at EPA, 2008, 2018a). 

Exceedance of the TTAL for samples collected using EPA 

protocols may require additional tapwater quality monitoring, 

corrosion control treatment, source water monitoring/

treatment, public education, and replacement of lead 

service lines (EPA, 2008). For example, the City of East 

Chicago currently (2018) uses orthophosphate at an average 

concentration of 1.35 milligrams per liter (mg/L) for corrosion 

inhibition (Indiana General Assembly, 2018) and, under a fund 

from the Indiana Department of Environmental Management 

(IDEM), is replacing lead service lines in three Superfund 

zones to address concerns about Pb in tapwater. The NPDWR 

MCLG is defined as the level in drinking water below which 

there is no known or expected risk to health and is a nonenforceable public health goal (EPA, 2018c). The EPA has 

set the MCLG for Pb at zero (EPA, 2018c), “because lead is a 

toxic metal that can be harmful to human health even at low 

exposure levels” (EPA, 2018b).

The LCR is intended to minimize Pb levels in drinking 

water primarily through corrosion control and monitoring 

of community-water-system tapwater samples (EPA, 2008, 

2018a). The monitoring of Pb contaminants in tapwater 

under the LCR is focused on the protection of human health, 

including vulnerable populations (infants, young children, 

pregnant women), from possible contamination related to 

Pb-based materials (Pb pipes, Pb solder, and so forth) in the 

drinking-water distribution system (EPA, 2008, 2017, 2018a, 

2018c; Triantafyllidou and Edwards, 2012). Lead contaminants originating from Pb-based plumbing materials can leach 

into drinking water, leading to increasing dissolved concentrations under static conditions over time (Triantafyllidou 

and Edwards, 2012). Consequently, the protocol for LCR 

compliance monitoring is intended to target a presumptive 

“worst-case” exposure (EPA, 2008, 2016; Triantafyllidou and 

Edwards, 2012). Guidance for LCR compliance monitoring 

stipulates collection of “first-draw,” stagnant (minimum of 

6 hours since the last draw, typically overnight) samples of 

cold tapwater from a faucet without point-of-use treatment in 

homes in the service area that are considered to be at greatest 

risk of elevated Pb concentrations (EPA, 2016). 

In contrast, the USGS EHMA Greater Chicago Area 

Tapwater Exposure Study is being conducted to assess the 

potential human exposure to a broad suite of organic and 

inorganic contaminants in drinking water. This study is not 

focused specifically on Pb, and the sampling protocol does 

not include first-draw, stagnant sampling. All samples were 

collected with faucet screens (aerator screens) and point-of-use 

treatment equipment left in place. Domestic tapwater sample 

collections were distributed throughout the day, resulting in a 

range of pre-sample flushing periods. Information on resident 

water use prior to the beginning of sampling was not obtained. 

Trace element samples were the 11th (USGS National Water 

Quality Laboratory, NWQL) and 12th (Redox Chemistry 

Laboratory, RCL) containers in the sample collection 

sequence and were collected approximately 5 minutes after 

the faucet was turned on. Considering only the water used 

during the collection process, the USGS protocol involves 

flushing approximately 12 liters (3 gallons) of water prior 

to trace element sample collection. The tapwater Pb results 

reported herein are not appropriate for assessment of LCR 

compliance, because the samples were not collected using a 

first-draw, stagnant sampling protocol and, where present, 

were collected with the point-of-use treatment in place.

Purpose and Scope

The purpose of this report is to describe the site selection, 

sampling protocol, and inorganic chemical analytical methods 

used for the collection of samples of residential tapwater as well 

as samples of untreated (raw intake water) and treated (finished 

water) pre-distribution water from two Chicago water purification plants and two East Chicago water filtration plants during 

the EHMA’s Water and Wastewater Infrastructure Project’s 

Greater Chicago Area Tapwater Exposure Study. Samples 

discussed in this report were collected in Chicago, Illinois, 

and East Chicago, Indiana, during July–December 2017. This 

sampling was planned and implemented in cooperation with the 

UIC School of Public Health, City of Chicago Department of 

Water Management, City of East Chicago Utilities Department, 

and other non-governmental organizations. EPA regulations 

presented in this report are provided for reference only.

Methods

Site selection, sampling protocols, and analytical methods 

are described in this section.

Sampling Site Selection

Sampling sites were selected on the basis of the 

availability and permission of Chicago and East Chicago 

community volunteers. Sites in Chicago were selected to 

ensure equal number of samples and broad spatial coverage of 
4 Lead and Inorganic Constituents in Water From the Filtration Plant and Tapwater in Chicago, Ill., and East Chicago, Ind.

residences within the service areas of the two water filtration 

plants. Sites in East Chicago were selected to ensure samples 

were collected from residences within the area of documented 

soil Pb contamination and to provide broad spatial coverage of 

the East Chicago study area. One-time site access of approximately 30 minutes was required to complete the sampling 

of the domestic water supply at a kitchen tap. Samples were 

collected during July–December 2017 from a total of 45 

residences (table 1). All domestic tapwater station names, 

station numbers, location information, and collection times 

and dates are anonymized. Latitude and longitude data are 

generalized and do not indicate exact sampling site location. 

Additionally, for comparison purposes, water-quality samples 

were collected from the raw-water intake in Lake Michigan 

and from post-treatment (pre-distribution) locations two times 

each at the Chicago (July, November) water purification plant 

facilities and at the two East Chicago (August, September) 

water filtration plant facilities in operation at the time of 

residential sample collection (table 1). A water-parcel-tracking 

(Lagrangian) sampling approach was not used in this study. In 

other words, collections were not timed to sample a theoretical 

parcel of water as it moved from the raw-water intake 

through the filtration plant water and distribution system to 

individual residences.

Sampling Methods

Domestic tapwater sampling site visits were distributed 

throughout the day, as dictated by residents’ in-home availability. Detailed protocols, following guidelines established 

by the USGS (U.S. Geological Survey, variously dated), were 

provided to USGS personnel who conducted the sampling 

(Romanok and others, 2018b). An initial set of disposable 

gloves was donned to lay out a clean polyethylene (chamber 

bag) workspace on the floor in front of the kitchen sink 

and to record date and time on pre-labeled sample bottles. 

Fresh gloves were then donned to fill and cap narrow-neck 

sample bottles; sample collection began immediately after 

the faucet was turned on. Samples were collected with the 

faucet screen (aerator screen) in place. If the tap was equipped 

with a point-of-use treatment or other filtration device, the 

tapwater sample was collected post-treatment/filtration and the 

treatment device was visually inspected and noted along with 

the resident’s recollection of the device maintenance history 

(table 1). Approximately 30 containers for each sample were 

filled with cold tapwater in the same sequence established 

for previous USGS tapwater studies in order to improve 

comparison of results. After all samples were collected at a 

given site, field properties (dissolved oxygen [mg/L], water 

temperature [degrees Celsius], specific conductance [microsiemens per centimeter at 25 degrees Celsius, μS/cm], and 

pH [standard units]) were measured in an open chamber with 

water flowing (Romanok and others, 2018b). Total sample 

collection time (including measurements of field properties) 

was approximately 20 minutes. No information was obtained 

about the composition or materials in residential (curb-to-tap) 

drinking-water service lines and plumbing. 

Two samples were collected in polyethylene containers for 

trace element analysis (Fishman and Friedman, 1989; Hoffman 

and others, 1996; Hergenreder, 2011; USEPA, 2014). For the 

first sample, an acid-rinsed, 250-milliliter (mL), narrow-neck 

(28-mL) polyethylene bottle was pre-rinsed three times with 

sample water, and samples were collected as follows. Approximately 20 mL of tapwater was collected, capped, vigorously 

shaken, and discarded. The bottle was then filled to the shoulder 

with tapwater, preserved with 2 mL of 7.5 Normality, ultrapure 

grade, nitric acid (HNO3), capped, shaken to completely mix, 

sealed in two self-closing plastic bags, and placed on ice. The 

trace element samples and other chemical analysis samples for 

each location were shipped together overnight, on ice, to the 

USGS Organic Geochemistry Research Laboratory (OGRL) 

in Lawrence, Kansas. All trace element samples were then 

aggregated into a single cooler and shipped overnight on ice 

to the USGS NWQL in Denver, Colorado. The second trace 

element sample was collected in a 15-mL polyethylene Falcon 

tube, acidified with 150 microliters of 7.5 Normality, ultrapure 

grade, nitric acid, similarly bagged, and shipped overnight to the 

RCL in Boulder, Colo. Because the trace element samples were 

the 11th and 12th containers in the sample collection sequence, 

these samples were collected approximately 5 minutes after 

the faucet was turned on and after approximately 12 liters 

(3 gallons) of water flow.
Methods 5

Table 1. Concentration results of lead analyzed by the U.S. Geological Survey, National Water Quality Laboratory, Denver, Colorado, 

and Redox Chemistry Laboratory, Boulder, Colorado, for the U.S. Geological Survey Environmental Health Mission Area, Water and 

Wastewater Infrastructure Project, Tapwater Study, Chicago, Illinois, and East Chicago, Indiana, July–December, 2017.—Continued

[Samples were collected, during five trips, as part of the U.S. Geological Survey Environmental Health Mission Area, Water and Wastewater Infrastructure 

Project, Tapwater Study, East Chicago, Indiana, July–December 2017. Reporting levels: ICP-MS, 0.020 μg/L; GFAAS, 0.600 μg/L; ICP-OES, 0.008 mg/L. 

Abbreviations: ICP-MS, inductively coupled plasma-mass spectrometry; ICP-OES, inductively coupled plasma-optical emission spectrometry; GFAAS, 

graphite furnace atomic absorption spectrometry; mg/L, milligrams per liter; μg/L, micrograms per liter; WFP, water filtration plant; WT, treated water; WS, 

surface water; NA, not analyzed; <, less than; —, not relevant]

Station number State Station name Medium 

code

Sampling 

trip

Lead

(μg/L, 

ICP-MS1)

Lead 

(μg/L, 

GFAAS2)

Lead 

(mg/L, 

ICP-OES3)

Point-of-use 

treatment2

414500087320009 Illinois 38N-15E-29 001 (raw water) WS Trip 1 0.098 NA NA —–

414500087320010 Illinois 38N-15E-29 002 (pre-distribution 

water)

WT Trip 1 <0.020 NA NA —

415300087360009 Illinois 39N-14E-10 001 (raw water) WS Trip 1 0.083 <0.6 <0.008 —

415300087360010 Illinois 39N-14E-10 002 (pre-distribution 

water)

WT Trip 1 <0.020 NA NA —

91808900008 Indiana IN5245012 LAKE EAST 

CHICAGO WATER WORKS 

(WFP 1 pre-distribution)

WT Trip 2 <0.020 <0.600 <0.008 —

413700087270001 Indiana 37N 9W 28 003 WT Trip 2 2.49 2.61 <0.008 Yes

413700087270002 Indiana 37N 9W 33 004 WT Trip 2 0.020 <0.600 <0.008 Yes

413700087280001 Indiana 37N 9W 29 002 WT Trip 2 0.090 <0.600 <0.008 No

413700087280002 Indiana 37N 9W 28 007 WT Trip 2 1.15 <0.600 <0.008 Yes

413800087260001 Indiana 37N 9W 22 006 WT Trip 2 1.92 1.16 <0.008 No

413800087260002 Indiana 37N 9W 27 012 WT Trip 2 0.740 <0.600 <0.008 No

413800087270001 Indiana 37N 9W 21 013 WT Trip 2 0.280 <0.600 <0.008 No

413800087270002 Indiana 37N 9W 22 005 WT Trip 2 0.060 <0.600 <0.008 No

413800087280001 Indiana 37N 9W 29 001 WT Trip 2 0.530 <0.600 <0.008 No

413900087260001 Indiana IN5245012 LAKE 00087 INTAKE 1

LAKE MICHIGAN 

(WFP 1 raw water)

WS Trip 2 0.130 <0.600 <0.008 —

413900087260003 Indiana IN5245012 LAKE 05021 INTAKE 2

LAKE MICHIGAN 

(WFP 2 raw water)

WS Trip 2 0.210 <0.600 <0.008 —

413900087260004 Indiana 37N 9W 22 008 

(WFP 2 pre-distribution)

WT Trip 2 <0.020 <0.600 <0.008 —

91808900008 Indiana IN5245012 LAKE EAST 

CHICAGO WATER WORKS 

(WFP 1 pre-distribution)

WT Trip 3 <0.020 <0.600 <0.008 —

413900087260001 Indiana IN5245012 LAKE 00087 INTAKE 1

LAKE MICHIGAN 

(WFP 1 raw water)

WS Trip 3 0.250 <0.600 <0.008 —

413900087260003 Indiana IN5245012 LAKE 05021 INTAKE 2

LAKE MICHIGAN 

(WFP 2 raw water)

WS Trip 3 0.330 <0.600 <0.008 —

413900087260004 Indiana 37N 9W 22 008 

(WFP 2 pre-distribution)

WT Trip 3 <0.020 <0.600 <0.008 —

413700087260001 Indiana 37N 9W 27 018 WT Trip 3 1.12 0.921 <0.008 No

413700087270003 Indiana 37N 9W 33 015 WT Trip 3 0.480 <0.600 <0.008 Yes

413700087270004 Indiana 37N 9W 27 017 WT Trip 3 0.020 <0.600 <0.008 Yes

413800087260003 Indiana 37N 9W 22 016 WT Trip 3 <0.020 <0.600 <0.008 Yes

413800087260004 Indiana 37N 9W 27 019 WT Trip 3 1.58 1.38 <0.008 No

413800087280002 Indiana 37N 9W 29 014 WT Trip 3 1.36 1.00 <0.008 No
6 Lead and Inorganic Constituents in Water From the Filtration Plant and Tapwater in Chicago, Ill., and East Chicago, Ind.

Table 1. Concentration results of lead analyzed by the U.S. Geological Survey, National Water Quality Laboratory, Denver, Colorado, 

and Redox Chemistry Laboratory, Boulder, Colorado, for the U.S. Geological Survey Environmental Health Mission Area, Water and 

Wastewater Infrastructure Project, Tapwater Study, Chicago, Illinois, and East Chicago, Indiana, July–December, 2017.—Continued

[Samples were collected, during five trips, as part of the U.S. Geological Survey Environmental Health Mission Area, Water and Wastewater Infrastructure 

Project, Tapwater Study, East Chicago, Indiana, July–December 2017. Reporting levels: ICP-MS, 0.020 μg/L; GFAAS, 0.600 μg/L; ICP-OES, 0.008 mg/L. 

Abbreviations: ICP-MS, inductively coupled plasma-mass spectrometry; ICP-OES, inductively coupled plasma-optical emission spectrometry; GFAAS, 

graphite furnace atomic absorption spectrometry; mg/L, milligrams per liter; μg/L, micrograms per liter; WFP, water filtration plant; WT, treated water; WS, 

surface water; NA, not analyzed; <, less than; —, not relevant]

Station number State Station name Medium 

code

Sampling 

trip

Lead

(μg/L, 

ICP-MS1)

Lead 

(μg/L, 

GFAAS2)

Lead 

(mg/L, 

ICP-OES3)

Point-of-use 

treatment2

414100087320001 Illinois 37N 15E 18 021 WT Trip 4 0.489 <0.600 <0.008 No

414200087400001 Illinois 37N 14E 7 023 WT Trip 4 0.03 <0.600 <0.008 Yes

414200087400002 Illinois 37N 14E 7 024 WT Trip 4 5.31 5.46 <0.008 No

414300087320001 Illinois 37N 15E 6 020 WT Trip 4 3.74 3.28 <0.008 No

414300087330001 Illinois 37N 15E 7 022 WT Trip 4 0.404 <0.600 <0.008 No

414500087320010 Illinois 38N-15E-29 002 

(pre-distribution water)

WT Trip 4 <0.020 <0.600 <0.008 —

415300087360009 Illinois 39N-14E-10 001 (raw water) WS Trip 4 0.104 0.52 <0.008 —

415300087360010 Illinois 39N-14E-10 002 

(pre-distribution water)

WT Trip 4 <0.020 <0.600 <0.008 —

415400087420001 Illinois 40N 13E 36 028 WT Trip 4 1.78 1.51 <0.008 No

415400087420002 Illinois 40N 13E 36 029 WT Trip 4 1.34 1.77 <0.008 No

415500087410001 Illinois 40N 13E 36 026 WT Trip 4 0.031 <0.600 <0.008 No

415500087410002 Illinois 40N 13E 25 027 WT Trip 4 1.53 1.30 <0.008 No

415500087420001 Illinois 40N 13E 25 030 WT Trip 4 0.344 <0.600 <0.008 No

415600087380001 Illinois 40N 14E 28 025 WT Trip 4 0.133 <0.600 <0.008 No

415700087410001 Illinois 40N 13E 13 033 WT Trip 4 0.8 0.94 <0.008 No

415700087440001 Illinois 40N 13E 15 031 WT Trip 4 1.75 1.43 <0.008 No

415800087390001 Illinois 40N 14E 17 034 WT Trip 4 <0.020 <0.600 <0.008 No

415800087420001 Illinois 40N 13E 11 032 WT Trip 4 3.43 3.10 <0.008 No

414400087440001 Illinois 38N 13E 34 045 WT Trip 5 0.481 <0.600 <0.008 No

414600087390001 Illinois 38N 14E 20 044 WT Trip 5 <0.020 <0.600 <0.008 No

414700087340001 Illinois 38N 14E 12 047 WT Trip 5 0.4 <0.600 <0.008 No

414700087350001 Illinois 38N 14E 11 048 WT Trip 5 2.06 1.41 <0.008 No

414700087350002 Illinois 38N 14E 11 049 WT Trip 5 0.616 <0.600 <0.008 No

414700087350003 Illinois 38N 14E 14 050 WT Trip 5 0.486 <0.600 <0.008 No

414700087350004 Illinois 38N 14E 12 051 WT Trip 5 <0.020 <0.600 <0.008 No

414800087350001 Illinois 38N 14E 11 052 WT Trip 5 0.0200 <0.600 <0.008 No

414800087360001 Illinois 38N 14E 3 043 WT Trip 5 0.03 <0.600 <0.008 No

414800087360002 Illinois 38N 14E 11 046 WT Trip 5 1.63 1.00 <0.008 No

414900087360001 Illinois 38N 14E 2 042 WT Trip 5 0.047 <0.600 <0.008 No

415400087410001 Illinois 39N 13E 01 039 WT Trip 5 <0.020 <0.600 <0.008 No

415500087460001 Illinois 40N 13E 32 038 WT Trip 5 3.37 7.60 <0.008 No

415800087390002 Illinois 40N 14E 08 040 WT Trip 5 <0.020 <0.600 <0.008 No

420000087380001 Illinois 41N 14E 32 041 WT Trip 5 0.032 <0.600 <0.008 No

1

Fishman and Friedman (1989); Hoffman and others (1996).

2

Hergenreder (2011).

3

EPA (2014).
Results 7

Analytical Methods

Samples from 45 residential kitchen taps and the four 

Chicago and four East Chicago water filtration plant locations 

(two locations in each of the four facilities) were analyzed at 

the NWQL and RCL for concentrations of trace elements by 

using three analytical methods. Results for all trace element 

analytes, in milligrams per liter and micrograms per liter, are 

available for download at (Romanok and others, 2018a). Lead 

concentrations are summarized in table 1.

National Water Quality Laboratory

Whole-water samples were analyzed for 27 trace 

elements, including Pb, as described in (Fishman and 

Friedman, 1989; Hoffman and others, 1996). Briefly, samples 

were digested with hydrochloric acid, heated, and analyzed 

by inductively coupled plasma-mass spectrometry (ICP-MS) 

or by atomic absorption (cadmium and calcium) (as described 

in Fishman and Friedman, 1989; Hoffman and others, 1996). 

Trace element concentrations, including Pb, are reported in 

microgram per liter concentrations. The reporting level (RL) 

type used by the NWQL varies by analyte. The RL type used 

to report Pb concentrations is DLBLK, meaning the detection 

level is determined using blank data. A description of how 

this RL is determined can be found in U.S. Geological Survey 

(2015). The detection level for Pb, for this analytical method, 

was 0.020 μg/L.

Redox Chemistry Laboratory 

Whole-water samples were analyzed for 32 inorganic 

constituents and alkalinity at the RCL. Cations and trace 

elements were analyzed using inductively coupled plasmaoptical emissions spectrometry (ICP-OES); anions were 

analyzed using ion chromatography; and alkalinity was 

determined using an automated titration, with first derivative 

near pH 4.5 (Pfaff, 1993; EPA, 2014). Trace element cations 

(including Pb) and anions are reported in milligrams per liter, 

and alkalinity is reported in milligrams per liter of bicarbonate. 

Concentrations of lead were also analyzed by graphitefurnace, atomic-absorption spectrometry (GFAAS), and results 

are reported in micrograms per liter. The method detection 

limit (MDL) (Childress and others, 1999; EPA, 2005) for 

Pb by GFAAS was 0.600 μg/L. The MDL for Pb, using the 

ICP-OES method, was 0.008 mg/L.

Quality Assurance/Quality Control

Field blanks were collected as part of the quality 

assurance/quality control (QAQC) protocols at three sites 

(station numbers: 414500087320010, 91808900008, 

413900087260001) and analyzed at the NWQL and RCL to 

determine if any contamination bias was introduced during 

sampling. Field blank samples analyzed at the NWQL had 

detections for two trace elements, copper (0.400 μg/L) and 

silver (0.200 μg/L) (Romanok and others, 2018a). Reporting 

limits for copper and silver are 0.200 and 0.030 μg/L, 

respectively. Additionally, field blanks analyzed at RCL 

had detections for alkalinity (6.0 mg/L, as bicarbonate) and 

calcium (0.013 and 0.021 mg/L) (Romanok and others, 

2018a). Method detection limits for alkalinity and calcium are 

2.00 mg/L, as bicarbonate, and 0.006 mg/L, respectively. Lead 

was not detected in any field blank, using any method.

Results

Lead concentration results are summarized in table 1. 

Concentration data for all analyzed trace elements and 

alkalinity are provided in Romanok and others (2018a). 

Inorganic constituents regulated under the NPDWR or LCR 

are summarized in table 2. Respective standards are listed for 

reference only.
8 Lead and Inorganic Constituents in Water From the Filtration Plant and Tapwater in Chicago, Ill., and East Chicago, Ind.

Chicago and East Chicago Water Filtration 

Plant Sampling

Four water purification/filtration plant facilities (two in 

Chicago; two in East Chicago) supplied drinking water to 

residences included in 2017 Chicago Area Tapwater Exposure 

Study. Samples of raw water from Lake Michigan (7 total 

samples) and treated, pre-distribution drinking water (8 total 

samples) were collected at all four facilities during the 

residential tapwater sampling period. Lead, which has an RL 

of 0.020 μg/L, was detected only in raw-water intake samples 

(at all four facilities, in all collected samples) and only by 

using the most sensitive NWQL method (ICP-MS) (Fishman 

and Friedman, 1989; Hoffman and others, 1996) (table 1). 

Lake Michigan raw-water intake Pb concentrations ranged 

from 0.083 to 0.330 μg/L, with a median of 0.130 μg/L 

(table 1). Lead was not detected in any samples of treated, 

pre-distribution drinking water at either facility. No other 

inorganic constituents were detected in raw intake water or 

in treated, pre-distribution drinking water in excess of the 

respective EPA MCLG (public health goal) (table 2). 

Table 2. Maximum concentrations of trace elements detected in tapwater for the U.S. Geological Survey Environmental Health 

Mission Area, Water and Wastewater Infrastructure Project, Tapwater Study, Chicago, Illinois, and East Chicago, Indiana, 

July–December, 2017.

[U.S. Environmental Protection Agency (EPA) standards and public health goals are listed for reference only. Abbreviations: MCL, EPA Maximum 

Contaminant Level; TTAL, EPA Treatment Technique Action Level; —, not analyzed; mg/L, milligrams per liter; RLC, Redox Chemistry Laboratory; 

NWQL, National Water Quality Laboratory; <, less than]

Trace element MCL1

(mg/L)

Public health goal1

(mg/L)

Maximum value, RCL 

(mg/L)

Maximum value, NWQL2

(mg/L)

Antimony 0.006 0.006 <0.030 0.00019

Arsenic 0.010 zero < 0.040 0.001

Barium 2.00 2.00 0.108 0.022

Beryllium 0.004 0.004 <0.0005 0.00004

Cadmium 0.005 0.005 <0.003 0.00009

Chromium 0.100 (total) 0.100 0.002 0.0007

Copper 1.30 TTAL 1.30 0.019 0.036

Fluoride 4.00 4.00 0.723 —

Lead 0.015 TTAL zero 0.0083/<0.0084 0.005

Selenium 0.050 0.050 <0.040 0.0003

Thallium 0.002 0.0005 — 0.00002

Uranium 0.030 zero <0.010 0.0004

1

EPA (2009).

2

Fishman and Friedman (1989); Hoffman and others (1996).

3

Hergenreder (2011).

4

EPA (2014).

Chicago Area Tapwater Sampling

Lead was detected at or above the RL (0.020 μg/L) 

in 39 (87 percent) of the 45 residential tapwater samples 

collected for this study (table 1). Lead concentrations in 

tapwater ranged from below the reporting limit to 5.31 μg/L, 

with a median of 0.481 μg/L. The MCLG for Pb is zero, and 

39 of 45 tapwater samples had detectable Pb concentrations 

when using the most sensitive method of analysis. No other 

inorganic constituents were detected in tapwater in excess of 

the corresponding EPA MCLG (public health goal) (table 2).

Discussion

The steps suggested by the EPA (2018a) to reduce Pb 

exposure in home drinking water include installation and 

proper maintenance of a point-of-use (at the tap) water filter 

that is certified to remove Pb. Six of the 15 East Chicago 

homes and one of the 30 Chicago homes sampled for this 

study had point-of-use (at the tap) water filters installed at 
References Cited 9

the time of sampling, and some of the lowest tapwater Pb 

concentrations in the study were observed in four of these 

locations. The fifth highest concentration of Pb detected in the 

study (2.49 μg/L) corresponded to an unmaintained point-ofuse filter unit. 

The results of sampling reported for Pb and inorganic 

constituents in Chicago Area tapwater are only a subset of a 

broad suite of chemical constituents and microbial communities being assessed by the USGS as part of ongoing studies 

of tapwater in the Greater Chicago Area and elsewhere in the 

United States. The completed sample collections and datasets 

are intended to provide insight into those water infrastructure 

components and processes (such as source-water corrosivity, 

treatment, plumbing, and so forth) that might influence human 

exposure to chemical and microbial contaminants at the 

residential tap. Conducted in collaboration with colleagues 

and stakeholders from academia, public health agencies, and 

water utilities, this work can contribute to the foundational 

understanding of potential associations between human-health 

effects and drinking-water exposures at the tap.

EPA Guidance on Reducing Pb 

Exposure in Home Drinking Water

The EPA lists five approaches to reduce exposure to Pb in 

home drinking water (EPA, 2018a).

• “Use only cold water for drinking, cooking and making

baby formula. Boiling water does not remove lead

from water.

• Regularly clean your faucet’s screen (also known as an

aerator).

• Consider using a water filter certified to remove lead

and know when it’s time to replace the filter.

• Before drinking, flush your pipes by running your tap,

taking a shower, doing laundry or a load of dishes.

• Contact your water system to learn more about sources

of lead and removing lead service lines.”

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Romanok and others—Lead and Other Inorganic Constituents in Water From the Filtration Plant and Tapwater in Chicago, Ill., and East Chicago, Ind.—Open-File Report 2018–1071

ISSN 2331-1258 (online)

https://doi.org/10.3133/ofr20181071