Mercury in the Grand Calumet River/

Indiana Harbor Canal and Lake Michigan,

Lake County, Indiana,

August 2001 and May 2002

By Martin R. Risch

U.S. Department of the Interior

U.S. Geological Survey

PreparedincooperationwiththeIndianaDepartmentofEnvironmentalManagement

ScientificInvestigationsReport 2005-5034
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2005

For sale by U.S. Geological Survey, Information Services 

Box 25286, Denver Federal Center 

Denver, CO 80225

For more information about the USGS and its products: 

Telephone: 1-888-ASK-USGS 

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

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.
iii

Contents

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

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

PurposeandScope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Mercury intheEnvironment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

DescriptionoftheStudyArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Previous InvestigationsofMercury intheStudyArea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Mercury inSurfaceWater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Mercury inFish,Sediment,AtmosphericDeposition,andGroundWater. . . . . . . . . . . . . . . . . . . . . . . . 6

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

StudyDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

SamplingLocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

SamplingProcedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

EquipmentandSupplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

WatercraftandVehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

SampleCollection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Water-QualityAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

QualityControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Streamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Mercury intheGrandCalumetRiver/IndianaHarborCanalandLakeMichigan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

TotalMercuryandMethylmercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Mercury inEnvironmentalSamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Mercury inQuality-Control Field-BlankSamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

FactorsAffectingMercuryConcentrationsandMercuryTransport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

WeatherandStreamflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

SuspendedSedimentandSuspendedFineParticulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

NaturalVariabilityofMercuryConcentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Water-QualityConstituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

TotalMercury Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Implications foraTotalMaximumDaily Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

ComparisonswithHistoricalData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Mercury inEffluentSamples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Mercury inGround-WaterDischarge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

InputsofMercury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

SummaryandConclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

ReferencesCited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
iv 

Appendixes—

1–1.—1–6. Tablesoftotalmercuryandmethylmercuryconcentrations;estimatedloadsof

combinedtotalmercury;water-qualitycharacteristics,physicalproperties,andmajor

ions;unfilteredtotalmercuryandwater-qualitycharacteristicsofeffluent samples;

totalmercury infield-blank samples;andvariabilityof selectedconstituents in

sequentialduplicatesamples,GrandCalumetRiver/IndianaHarborCanaland

LakeMichigan, LakeCounty,Indiana,August 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2–1.—2–6. Tablesoftotalmercuryandmethylmercuryconcentrations;estimatedloadsof

combinedtotalmercury;water-qualitycharacteristics,physicalproperties,andmajor

ions;unfilteredtotalmercuryandwater-qualitycharacteristicsofeffluent samples;

totalmercury infield-blank samples;andvariabilityof selectedconstituents in

sequentialduplicatesamples,GrandCalumetRiver/IndianaHarborCanaland

LakeMichigan,May 2002. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3–1. TableofU.S.GeologicalSurveyNationalWaterInformationSystemsite-identification

numbers forlocations sampledintheGrandCalumetRiver/IndianaHarborCanal

andLakeMichigan,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Figures

1.–2. Illustrations showing—

1. Sourcesofmercuryandmercurycyclinginaquaticecosystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. Accumulationandmagnificationofmercury inthefoodchain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3.–5. Maps showing—

3. Studyareaformercury intheGrandCalumetRiver/IndianaHarborCanaland

LakeMichiganinLakeCounty,Indiana,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4. LocationsofIndianamonitoringstations formercury inwetdepositionduring2001

and2002. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5. Samplinglocations formercury intheGrandCalumetRiver/IndianaHarborCanaland

LakeMichigan,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

6. Illustrationshowingperistaltic-pumpapparatusformercurysampling,August2001and

May 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

7. PhotographshowingwatercraftandU.S.GeologicalSurveypersonnelduringmercury

sampling,August 2001. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

8.–9. Maps showing—

8. Combinedtotalmercuryconcentrations intheGrandCalumetRiver/IndianaHarborCanal

andLakeMichigan,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

9. Estimatedloadsofcombinedtotalmercuryduringthetimeof samplingat selectedlocations

intheGrandCalumetRiver/IndianaHarborCanal,August 2001andMay 2002 . . . . . . . . . . . . . . . . . 23
v

Tables

1. Mercuryconcentrationsandmercurywet-depositionrates forNationalAtmosphericDeposition

ProgramMercuryDepositionNetworkmonitoringstations inIndianaandNorthAmerica . . . . . . . . . 7

2. Locations formercury samplingintheGrandCalumetRiver/IndianaHarborCanaland

LakeMichigan, LakeCounty,Indiana,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3. Constituents,containers,treatment,andpreservationfor samplingduringAugust 2001and

May 2002 inLakeCounty,Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4. Analyticalmethods for supplementaryconstituents inwater samplesduringAugust 2001and

May 2002 inLakeCounty,Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5. Rangesofcombinedtotalmercuryandmethylmercuryconcentrations inwater samples

fromgroupsof samplinglocationsontheGrandCalumetRiver/IndianaHarborCanaland

LakeMichigan, LakeCounty,Indiana,August 2001andMay 2002. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

6. Rangesofcombinedmethylmercuryasapercentageofcombinedtotalmercury inwater

samples fromgroupsof samplinglocations,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7. Rangesofparticulatetotalmercuryasapercentageofcombinedtotalmercury inwater

samples fromgroupsof samplinglocations,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8. Streamflowat 10 samplinglocationsandsuspended-sedimentconcentrationinwater samples,

August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

9. Suspended-sedimentconcentrations insequentialduplicatewater samples fromfivesampling

locations,May 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

10. Proportionsof suspendedfineparticulates,particulateorganiccarbon,andplantpigments in

sestonofwater samples fromgroupsof samplinglocations,August 2001andMay 2002 . . . . . . . . . . 21

11. Rangesofconcentrationsofdissolvedsolids,totalorganiccarbon,andsulfateinwater samples

fromgroupsof samplinglocations,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

12. Estimatedloadsofcombinedtotalmercuryduringthetimeof samplingateight sampling

locations,August 2001andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

13. Concentrationsoftotalmercury inwater samples fromsevensamplinglocations,July 1999,

August 2001,andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

14. Maximumestimatedloadsoftotalmercury inground-waterdischarges tostreamreaches

andmaximuminstantaneous loadsoftotalmercuryateight samplinglocations,August 2001

andMay 2002 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
vi

Conversion Factors, Vertical Datum,

Abbreviated Concentration Units, and Acronyms

Temperature is given in degrees Celsius (C), which may be converted to degrees Fahrenheit (

oF) 

as follows:

oF = 1.8 X o

C + 32

Vertical Datum: In this report, vertical coordinate information is referenced to the North 

American Vertical Datum of 1988 (NAVD 88).

Abbreviated concentration units used in this report (including appendix): 

Chemical concentrations are given in metric units, microgram per kilogram (μg/kg), milligram per 

liter (mg/L), microgram per liter (μg/L), or nanogram per liter (ng/L). Microgram per kilogram is a 

unit expressing the concentration of a chemical in a solid as weight (microgram) of the chemical 

per unit weight (kilogram) of soil. One mg/kg is equal to 1,000 μg/kg. Milligram or microgram 

or nanogram per liter is a unit expressing the concentration of a chemical in solution as weight 

(milligram or microgram or nanogram) of the chemical per unit volume (liter, L) of water. One 

mg/L is equivalent to 1,000 μg/L, and 1 μg/L is equivalent to 1,000 ng/L. For concentrations 

less than 7,000 mg/kg, the numerical value is the same as for concentrations in parts per million; 

1 μg/kg is equivalent to 1 part per billion. 

Specific conductance of water is expressed in microsiemens per centimeter at 25o Celsius 

(μS/cm). This unit is equivalent to micromhos per centimeter at 25o Celsius (μmho/cm), formerly 

used by the U.S. Geological Survey.

Nephelometric turbidity unit (ntu) is the unit of measurement for reporting turbidity that is based 

on use of a standard suspension of Formazin. Turbidity measured in ntu uses nephelometric 

methods that depend on passing light of a specific wavelength through the sample.

Volumes of water-quality samples are given in liters (L) and milliliters (mL).

Multiply By To obtain

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

square mile (mi2

) 2.590 square kilometer (km2)

cubic foot per second (ft3

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

pound (lb) 0.4536 kilogram (kg)

micrometer (μm) 0.000039 inch (in.)

square meter (m2

) 10.76 square foot (ft2)

gram per year (g/yr) 0.03527 ounce per year (oz/yr)

milligram (mg) 0.00003527 ounce (oz)

milligram per hour (mg/hr) 0.00003527 ounce per hour (oz/hr)

nanogram (ng) 0.00000003527 ounce (oz)

nanogram per square meter (ng/m2

) 0.0000003795 ounce per square foot (oz/ft2)
vii

Acronyms used in this report:

Acronym Description

ADCP Acoustic Doppler Current Profiler

IDEM Indiana Department of Environmental Management

MDN Mercury Deposition Network

NADP National Atmospheric Deposition Program

RPD Relative Percent Difference

TMDL Total Maximum Daily Load

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

Mercury in the Grand Calumet River/Indiana Harbor Canal 

and Lake Michigan, Lake County, Indiana, 

August 2001 and May 2002

By Martin R. Risch 

Abstract

Water samples from the Grand Calumet River/Indiana 

Harbor Canal and Lake Michigan in Lake County, Indiana, 

were collected and analyzed for mercury. Sampling was 

done with ultra-clean protocols, and mercury was analyzed 

by low-level methods during seasons of contrasting weather 

and streamflow conditions in August 2001 and May 2002. 

Total mercury concentrations in all the Grand Calumet 

River/Indiana Harbor Canal samples exceeded the 1.3 nanogram per liter Indiana water-quality standard for waters 

within the Great Lakes system. Total mercury concentrations 

in the Lake Michigan samples did not exceed the Indiana 

water-quality standard. Total mercury and methylmercury 

concentrations were larger in more samples collected during 

the wet-weather streamflow conditions in May 2002 than 

in samples collected during the dry-weather streamflow conditions in August 2001. The largest total mercury concentrations 

were in samples collected from the West Branch Grand Calumet River near wetlands and municipal-effluent outfalls 

(17.2 nanograms per liter) and in samples collected from the 

Indiana Harbor Canal near the confluence of the East Branch 

and West Branch Grand Calumet River (16.0 nanograms 

per liter). 

Particulate total mercury was the predominant form of 

total mercury detected in samples from the Grand Calumet 

River/Indiana Harbor Canal. Methylmercury concentrations 

were no more than 1.5 percent of the total mercury concentrations in August 2001 and no more than 6.2 percent in May 2002. 

Nearly all methylmercury was particulate and was correlated 

to concentrations of dissolved solids, total organic carbon, and 

sulfate. The estimated composition of most of the suspended 

solids in the water samples from the Grand Calumet River/ 

Indiana Harbor Canal was sediment larger than medium clay 

containing minimal organic carbon and plant matter. Total mercury loads in the Indiana Harbor Canal during the time of water 

sampling were as large as 703 milligrams per hour in August 

2001 and 542 milligrams per hour in May 2002. As much as 

21 percent of the instantaneous mercury load in some stream 

reaches could have come from ground-water discharge.

Data from this study have implications for a Total Maximum Daily Load (TMDL) for mercury in the Grand Calumet 

River/Indiana Harbor Canal. Comparisons of data from this 

study with historical data do not show substantial changes in the 

distribution of mercury in the study area from 1994 through 

2002. Treated municipal effluent had larger mercury concentrations than industrial effluent and presents a potential for larger 

mercury loads that could be controlled to achieve a TMDL, 

based on concentration. Mercury in ground-water discharge 

may be difficult to control to achieve a TMDL because of its 

diffuse and widespread distribution. 

Introduction

The Grand Calumet River/Indiana Harbor Canal was 

first on the Indiana Department of Environmental Management 

(IDEM) 1998 list of water bodies scheduled for development 

of a Total Maximum Daily Load (TMDL) for mercury under 

provisions of the Clean Water Act section 303(d). A TMDL 

is the largest amount of a specific pollutant (such as mercury) 

that will not cause in-stream violations of water-quality 

standards. Mercury was a parameter of concern because of 

a fish-consumption advisory for the Grand Calumet River/ 

Indiana Harbor Canal (Indiana Department of Environmental 

Management, 2001). The fish-consumption advisory was based 

on concentrations of mercury in tissue of fish from the Grand 

Calumet River/Indiana Harbor Canal that would pose a health 

risk to humans if consumed. If the mercury concentration in fish 

tissue results in a fish-consumption advisory, the Indiana waterquality standard1 of 1.3 nanograms per liter for waters within 

the Great Lakes system probably was exceeded. This standard 

protects wildlife that consume fish from health risks caused by 

mercury ingestion.

A TMDL, if developed, could be used by IDEM to limit 

mercury in discharges from permitted point sources on the 

1

Indiana Water Pollution Control Board, 2001, Title 327 of the Indiana 

Administrative Code, Article 2, Rule 1.5, section 8 (327 IAC 2-1.5-8): “Water 

quality standards applicable to all State Waters within the Great Lakes system, 

Minimum surface water quality criteria; Table 8–4: Water quality criteria for 

protection of wildlife; Mercury (including methylmercury).”
2 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Grand Calumet River/Indiana Harbor Canal in an attempt to 

achieve the Indiana water-quality standard. The mercury 

TMDL required a base line of mercury data with reporting 

limits less than the 1.3 ng/L Indiana water-quality standard. 

The IDEM historical data used reporting limits for mercury 

in water samples from the Grand Calumet River/Indiana Harbor 

Canal that were greater than the Indiana standard. Therefore, 

the historical data were not useful for a TMDL.

To attain the lower reporting limit needed for the mercury 

TMDL, IDEM requested that the U.S. Geological Survey 

(USGS) obtain data on the occurrence and distribution of mercury in the Grand Calumet River, the Indiana Harbor Canal, and 

near-shore Lake Michigan in Lake County, Indiana. The USGS 

collected samples with ultra-clean protocols and analyzed mercury by low-level methods. To get the base-line mercury data 

needed, the USGS sampled water in the Grand Calumet River/

Indiana Harbor Canal, selected discharges to the Grand Calumet River/Indiana Harbor Canal, and water in Lake Michigan 

near the water-supply intakes that eventually lead to the permitted discharges.

In addition, the USGS examined the spatial distribution of 

mercury, the proportions of total mercury and methylmercury 

in dissolved and particulate forms, seasonal differences in 

mercury concentrations, and the relation of hydrologic and 

chemical factors to mercury concentrations. This information 

could provide a basis for the Grand Calumet River/Indiana 

Harbor Canal mercury TMDL and for future efforts to develop 

a mercury TMDL for other water bodies, particularly in northwestern Indiana.

PurposeandScope

This report presents total mercury and methylmercury 

concentrations in surface-water samples collected in the Grand 

Calumet River/Indiana Harbor Canal and Lake Michigan 

during August 2001 and May 2002. Supplementary waterquality-constituent concentrations and instantaneous streamflow from those time periods also are reported. Relations 

among concentrations of mercury, water-quality constituents, 

and streamflow conditions are examined; mercury loads at the 

time of water sampling are estimated. Factors that may affect a 

mercury TMDL in the Grand Calumet River/Indiana Harbor 

Canal are discussed.

Mercury intheEnvironment

Sources of mercury in surface water include pointsource discharges of industrial and municipal wastewater and 

nonpoint-source atmospheric deposition, stormwater runoff, 

and ground-water discharge. Atmospheric deposition can contribute mercury directly to lakes and streams. Also, atmospheric 

deposition to the land can contribute mercury to stormwater 

runoff and to ground water that enters lakes and streams. 

Sources of mercury in the atmosphere can be from human activities (coal-fired power plants, waste incinerators, industrial 

boilers) or can be natural (forest fires, geologic formations, 

volcanoes). Once in the surface water, mercury can cycle 

through the sediment, the biota, the water column, and back 

to the atmosphere (fig. 1).

Methylmercury is produced from inorganic mercury by 

methylation, a microbial process that is controlled by certain 

bacteria and chemical variables such as organic matter, sulfate, 

and oxygen. Sources of mercury emissions to the atmosphere 

from human activities have been implicated for most of the 

methylmercury in fish (U.S. Environmental Protection Agency, 

1997). A national study of mercury in aquatic ecosystems 

(Krabbenhoft and others, 1999) indicated larger methylmercury 

concentrations were related to greater densities of wetlands. 

Concentrations of methylmercury magnify in the food chain 

so that higher-level organisms tend to accumulate higher concentrations of methylmercury (fig. 2). Fish living in aquatic 

ecosystems with extremely low concentrations of inorganic 

mercury are known to accumulate substantial amounts of 

methylmercury in their tissue (Krabbenhoft and Rickert, 1995). 

Mercury in Indiana’s water is a public-health and environmental concern. In Indiana, mercury has been detected in nearly 

all fish-tissue samples collected since 1983 (Stahl, 1997). Concentrations of mercury in some fish caught in Indiana waters 

have prompted health officials to issue advisories that warn 

about human consumption of these fish (Indiana State Department of Health and others, 2000). Mercury—especially in its 

organic form, methylmercury—can affect the central nervous 

system of adults and children. A primary exposure to methylmercury for humans is from eating fish caught in rivers and 

lakes. Because their nervous systems are still in development, 

infants and young children are predicted to have a greater susceptibility than adults to methylmercury’s detrimental effects 

(National Research Council, 2000). Mercury in Indiana’s water 

is an environmental concern because fish-eating wildlife can 

suffer damage to the central nervous system from mercury contamination (Krabbenhoft and Wiener, 1999)

DescriptionoftheStudyArea

The Grand Calumet River/Indiana Harbor Canal in Lake 

County in northwestern Indiana consists of the East Branch 

Grand Calumet River, the West Branch Grand Calumet River, 

and the Indiana Harbor Canal; a part of the West Branch 

extends into Illinois (fig. 3). As described in Renn (2000), 

the East Branch Grand Calumet River starts near the Grand Calumet Lagoons, flows west, and discharges to the Indiana Harbor 

Canal. Streamflow in the West Branch Grand Calumet River 

divides at a topographic high approximately 1.5 mi west of the 

confluence with the Indiana Harbor Canal. East of the divide, 

the West Branch flows toward the Indiana Harbor Canal; west 

of the divide, the West Branch flows toward Illinois. The Indiana Harbor Canal primarily flows north, discharges into the 

Indiana Harbor, and then into Lake Michigan. 
Introduction 3

Figure 1. Sources of mercury and mercury cycling in aquatic ecosystems. (Modified from 

Krabbenhoft and Rickert, 1995.)

VOLATILIZATION and

RE-DEPOSITION 

INORGANIC MERCURY

SEDIMENTATION

METHYLATION

METHYLMERCURY FOOD-CHAIN MAGNIFICATION

ATMOSPHERIC DEPOSITION 

OVERLAND RUNOFF

METHYLMERCURY

SEDIMENTATION

DE-METHYLATION

OUTFLOW POINT-SOURCE DISCHARGE STORMWATER DISCHARGE 

WET DEPOSITION

DRY DEPOSITION

GROUND-WATER DISCHARGE 

INORGANIC MERCURY METHYLMERCURY

METHYLATION

DE-METHYLATION

 DIFFUSION and

RE-SUSPENSION

Figure 2. Accumulation and magnification of mercury in the food chain. 

(Modified from National Wildlife Federation, 2000.)

 

 

 

Phytoplankton and Bacteria

Insects and Zooplankton

Small Fish and

 Aquatic Animals

Predator Fish

Increasing Mercury Concentration

Birds and

Mammals
4 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Figure 3. Study area for mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan in Lake County, Indiana, August 2001 and May 2002.

Grand Calumet 

River

Grand Calumet

Branch

East

Branch

Calumet River

Grand

West

Indiana Harbor Canal

ILLINOIS

INDIANA

INDIANA

STUDY

AREA

0

0 1

1 2

2

4

4

5

5

3

3

MILES

KILOMETERS

Gary 

Harbor

COOK COUNTY

LAKE COUNTY

Buffington

Harbor

Indiana

Harbor

Gary Airport

Base from U.S. Geological Survey digital data, 1:100,000, 1983

Albers equal-area conic projection

Standard parallels 29o 30' and 45o 30', central meridian -86o

Lake Michigan

Lagoons

87o 87 15' 00'' o 30' 00''

41o 40' 00''

41o 37' 30''

Wolf 

Lake

Lake

George

TYPICAL DIRECTION OF FLOW (from Renn, 2000)

Lake George Canal

EXPLANATION

(west)

(east)
Introduction 5

According to Crawford and Wangsness (1987) almost 

all of the flow in the Grand Calumet River/Indiana Harbor 

Canal resulted from industrial and municipal discharges, 

and substantial flow variations have occurred in the East 

Branch and West Branch Grand Calumet River and in the 

Indiana Harbor Canal. Also, changes in Lake Michigan water 

levels temporarily can reverse the direction of flow in the 

Indiana Harbor Canal and parts of the East Branch and West 

Branch Grand Calumet River. Parts of the Grand Calumet 

River/Indiana Harbor Canal have been dredged, channelized, 

and lined with metal sheet pile. The contribution from surfacewater runoff is small. The drainage area of the Grand Calumet 

River Basin is indeterminate (Stewart and others, 1999) but is 

estimated to be less than 50 mi2 (David Cohen, U.S. Geological Survey, 1999, oral commun.).

Fenelon and Watson (1993) report that the study area is 

underlain by a surficial aquifer that consists primarily of dune, 

beach, and lacustrine sands ranging from 0 to 65 ft in thickness. 

Thickest in the east, where the maximum saturated thickness is 

45 ft, the aquifer thins to the west and pinches out in lacustrine 

clay near the Indiana-Illinois state line. The aquifer is underlain 

by till and lacustrine clay that ranges from 50 to 140 ft in thickness. Model simulations of ground-water flow estimated the 

aquifer discharges about 15 ft3/s to sewers, about 10 ft3/s to 

the Grand Calumet River/Indiana Harbor Canal, and about 

4 ft3/s to Lake Michigan.

Previous InvestigationsofMercury intheStudyArea

Historically, concentrations of mercury in water samples 

analyzed by low-level methods have exceeded the Indiana 

water-quality standard of 1.3 ng/L total mercury in the Grand 

Calumet River/Indiana Harbor Canal but generally have not 

exceeded the standard in Lake Michigan. Previous investigations summarized in this section of the report indicated much 

of the reported mercury in surface water could be in particulate 

form, probably arising, in part, from contaminated sediment. 

Methylmercury was not determined in many of the historical 

analyses. Overall, mercury was detected in and appeared to 

be cycling from the atmosphere to ground water, surface water, 

and sediment; from sediment into surface water; and from 

surface water and sediment into fish. 

Mercury in Surface Water

Limited historical data were available for mercury in Lake 

Michigan and the Grand Calumet River/Indiana Harbor Canal. 

Two data sets were summarized for this report—the Lake Michigan Mass Balance Study in 1994 and 1995 sponsored by the 

U.S. Environmental Protection Agency (USEPA) and USGS 

sampling in July 1999.

Mercury in Lake Michigan

As part of the Lake Michigan Mass Balance Study, watercolumn samples from offshore and open water Lake Michigan 

were collected in 1994 and 1995 (Mason and Sullivan, 1997). 

Samples were collected and analyzed with methods comparable 

to low-level methods. From 132 samples, the mean concentration of total mercury was 0.32 ng/L; 36 percent of the total 

mercury was in particulate form. From 26 samples, the mean 

concentration of methylmercury was 0.013 ng/L; 25 percent of 

the methylmercury was in particulate form. Mercury concentrations were not stratified with depth, nor was there a north-south 

trend in concentrations. A budget for sources and sinks of mercury in Lake Michigan estimated that atmospheric deposition 

accounted for about 80 percent of the total input; about 17 percent of the total input was from tributaries (Mason and Sullivan, 

1997).

Mercury in the Grand Calumet River/ 

Indiana Harbor Canal

As part of the Lake Michigan Mass Balance Study, 11 

selected tributaries were sampled, including the Indiana Harbor 

Canal (Hurley and others, 1996). The study included 10 

USEPA-designated Areas of Concern and 1 background site. 

Samples were collected with ultra-clean protocols and analyzed 

by low-level methods. Two samples were collected at the Indiana Harbor Canal—one during summer base flow and one after 

a late summer/early fall storm. The total mercury concentration 

during base flow was 13.5 ng/L, of which 12.2 ng/L (90 percent) was particulate mercury. The total mercury concentration 

after the summer/fall storm was 7.75 ng/L, of which 7.25 ng/L 

(94 percent) was particulate mercury. In the two samples, the 

suspended particulate matter was 7 and 8 mg/L and the dissolved organic carbon was 3.25 and 3.50 mg/L. Among the 

trace metals detected (mercury, lead, zinc, cadmium, and 

copper), most were in the particulate form and mercury was 

the highest percentage particulate.The highest percentage for 

particulate metals in all the tributaries sampled was reported 

for the Indiana Harbor Canal. Contaminated sediments were 

implicated as a likely source of the particulate metals, including 

mercury (Hurley and others, 1996).

During July 1999, the USGS collected unfiltered samples 

for total mercury analysis by the low-level method—four from 

the Indiana Harbor Canal and six from the Grand Calumet 

River. The samples were collected without ultra-clean protocols, but quality-control blanks did not indicate laboratory- or 

sampling-artifact mercury (Richard Duwelius, U.S. Geological 

Survey, 2001, oral commun.). Mercury concentrations in the 

Indiana Harbor Canal ranged from 2.1 to 5.2 ng/L and from 1.5 

to 19 ng/L in the Grand Calumet River (Stewart and others, 

2001).
6 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Mercury in Fish, Sediment, 

Atmospheric Deposition, and Ground Water

Historical mercury data were summarized in this report for 

samples of a common and widespread fish species and for samples of streambed-sediment collected by IDEM in the study 

area. Data regarding mercury in atmospheric wet deposition 

were summarized for 2001 and 2002 from a monitoring station 

near the study area and compared with statewide, regional, and 

national atmospheric-deposition data. Mercury data from 

ground-water samples in the study area were summarized, 

including estimated loads of mercury in ground water discharged to the Grand Calumet River/Indiana Harbor Canal.

Mercury in Fish

The 2000 Indiana Fish Consumption Advisory (Indiana 

State Department of Health and others, 2000) listed a “do not 

eat because of high levels of contamination” advisory for fish 

from the Grand Calumet River/Indiana Harbor Canal. Mercury 

is the contaminant listed in the advisory for 12 size classes of 

seven species of fish in the Lake County tributaries of Lake 

Michigan, resulting in a “do not eat” or “limit consumption” 

advisory. 

A variety of fish species have been observed in the Grand 

Calumet River/Indiana Harbor Canal (Newhouse and others, 

1997); carp is one of the most common and widespread species. 

IDEM collected 9 to 22 individual carp at five locations in the 

Grand Calumet River/Indiana Harbor Canal, 1980 through 

1996, and obtained mercury analysis of whole carp and carp 

fillets (James Stahl, Indiana Department of Environmental 

Management, 2001, written commun.). Maximum concentrations of mercury for 66 samples of carp tissue from mixed-size 

classes and preparations (whole or fillet) at the five locations 

ranged from 142 to 267 μg/kg. Some of the maximum concentrations of mercury in carp in the Grand Calumet River/Indiana 

Harbor Canal approach the USEPA water-quality criterion 

for methylmercury, 300 μg/kg in fish tissue (U.S. Environmental Protection Agency, 2001a). Although reported as total 

mercury, nearly all of the mercury in fish tissue is presumed 

to be methylmercury, the form of mercury that bioaccumulates 

and biomagnifies in the food chain (U.S. Environmental Protection Agency, 1997 and 2001a). 

Mercury in Streambed Sediment

Streambed sediments can cycle mercury into the aquatic 

ecosystem for decades or longer (U.S. Environmental Protection Agency, 1997 and 2001a). Eight streambed-sediment 

composite samples collected by IDEM in 1994 and 1996 from 

six locations in the Grand Calumet River/Indiana Harbor Canal 

ranged from 20 to 230 μg/kg mercury on a dry-weight basis 

(James Stahl, Indiana Department of Environmental Management, 2000, written commun.). Among all IDEM streambedsediment data, the mean mercury concentration for Lake 

County was 300 μg/kg, compared with a statewide mean 

of 58 μg/kg and statewide 95th percentile of 341 μg/kg 

(Wente, 1997).

Mercury in Atmospheric Deposition

Atmospheric deposition, primarily wet deposition, can be 

a substantial source of mercury input to aquatic ecosystems 

(U.S. Environmental Protection Agency, 1997 and 2001a). 

Mason and Sullivan (1997) attributed atmospheric deposition 

as 80 percent of the total mercury input in the estimated total 

mercury budget for Lake Michigan.

In 2001 and 2002, wet-deposition samples were collected 

near the study area at the Indiana Dunes National Lakeshore, a 

monitoring site in the National Atmospheric Deposition Program (NADP) Mercury Deposition Network (MDN). The 

NADP is a cooperative research support program that collectively operates wet-deposition monitoring stations in North 

America and has sponsored the MDN since 1996. In 2002, the 

MDN had more than 70 active monitoring stations, including 

4 in Indiana (fig. 4).

Data for mercury concentrations and mercury wetdeposition rates at the Indiana Dunes National Lakeshore in 

2001 and 2002 are summarized in table 1; concentrations and 

rates for the Indiana and North American MDN stations are 

included for comparison. (If data from the Indiana Dunes 

National Lakeshore monitoring station are representative of the 

Grand Calumet River Basin drainage area, the atmospheric wet 

deposition of mercury in the basin in 2001 and 2002 was 

approximately 1,330 grams per year2.)

Mercury in Ground Water

Duwelius and others (1996) reported concentrations of 

mercury in the ground water of the Calumet region in Indiana 

and Illinois in June 1993; this study area includes the Grand 

Calumet River/Indiana Harbor Canal. Ultra-clean protocols 

were not used for mercury-sample collection and low-level 

methods were not used for mercury analysis. Mercury was 

detected at concentrations larger than 0.1 or 0.2 μg/L in 53 percent (69 of the 129) of the ground-water samples collected 

in the study area. Of the samples in which mercury was 

detected, 67 percent (46 of 69) were from the surficial aquifer. 

The maximum mercury concentration was 1.1 μg/L; the 

USEPA drinking-water standard (Maximum Contaminant 

Level) for mercury is 2 μg/L. Some of the estimated mercury 

concentrations between 0.1 to 0.2 μg/L could have been artifacts because mercury was detected in the laboratory blanks; 

2

The estimate for atmospheric wet deposition of mercury was computed 

with a 129.5-km2 (50-mi2) drainage area multiplied by the sum of the total 

annual mercury wet deposition of mercury at the Indiana Dunes National Lakeshore monitoring station (20,640 ng/m2).
Introduction 7

Figure 4. Locations of Indiana monitoring stations for mercury in wet 

deposition during 2001 and 2002.

EXPLANATION

MERCURY DEPOSITION NETWORK

 MONITORING STATION

Indiana Dunes 

National Lakeshore

Table 1. Mercury concentrations and mercury wet-deposition rates for National Atmospheric Deposition Program Mercury 

Deposition Network monitoring stations in Indiana and North America.

[ng/L, nanogram per liter; ng/m2, nanogram per square meter]

a

Data from U.S. Geological Survey (2003).

b

Data from National Atmospheric Deposition Program (2000) and Sweet and Prestbo (1999).

Monitoring station(s) Time period

Annual mean 

concentration 

of total mercury 

(ng/L)

Mean weekly 

wet deposition 

of total mercury 

(ng/m2

)

Annual total 

wet deposition 

of total mercury 

(ng/m2

)

Indiana Dunes National Lakeshorea 2001 12.0 226 11,050

Indiana Dunes National Lakeshorea 2002 13.0 213 9,590

Four monitoring stations in Indianaa 2001 11.6 225 11,900

Four monitoring stations in Indianaa 2002 12.8 253 11,500

Mercury Deposition Network stations 

in North Americab

1996 through1999 10.0 200 10,000
8 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

more confidence was reported for concentrations larger than 

1 μg/L. Mercury, ranging from 0.14 to 1.1 μg/L, was detected 

in 75 percent of the samples from 12 wells screened in the surficial aquifer near the Gary Airport; the median concentration 

was 0.14 μg/L, which is equivalent to 140 ng/L. 

Willoughby and Siddeeq (2001) calculated chemical loads 

from ground water to the Grand Calumet River/Indiana Harbor 

Canal with historical ground-water-quality data and two different daily ground-water fluxes. The fluxes were based on 

two different horizontal hydraulic-conductivity values for 

the surficial aquifer (Fenelon and Watson, 1993). For mercury, 

estimated maximum loads from ground water ranged from 

8.3 to 83 mg/hr for selected reaches of the river.

Methods

This section describes the study design and selection of 

sampling locations for mercury in the Grand Calumet River/

Indiana Harbor Canal and Lake Michigan. The sampling procedures and equipment are discussed. The analytical methods and 

quality assurance for field determinations and laboratory analysis are explained. The technique for instantaneous streamflow 

measurement is described.

StudyDesign

Previous investigations indicated much of the mercury in 

Lake Michigan tributaries was particulate (Hurley and others, 

1996); it is likely then that suspended sediment in these tributaries included particulate mercury. From 1996 through 1998, 

the USGS analyzed 1,856 suspended-sediment samples and 

streamflow values from the Indiana Harbor Canal (Renn, 2000). 

Unlike in other streams in Indiana, no statistical relation 

between streamflow and suspended sediment was shown in the 

Indiana Harbor Canal; however, suspended-sediment concentrations were seasonally highest in spring and lowest in late 

summer. Therefore, mercury sampling was done in summer 

2001 and spring 2002 to investigate any influence of suspended 

sediment on particulate mercury. Dry summer weather and wet 

spring weather offered a contrast in streamflow with and without storm runoff. Also, summer and spring provided contrast in 

air and water temperature, affecting microbiological activity for 

methylmercury production.

Mercury can be dissolved in water and bound to suspended 

particulate matter in water (U.S. Environmental Protection 

Agency, 1997). In this study, dissolved total mercury and dissolved methylmercury were analyzed in filtered water samples. 

Particulate total mercury and particulate methylmercury were 

analyzed from the filters. To evaluate potential transport of 

mercury, water samples were analyzed for organic carbon, 

major ions and nutrients, and dissolved solids. To evaluate

potential transport of particulate mercury, the concentrations 

of suspended sediment, suspended fine particulates, and plant 

pigments (chlorophyll-a and pheophytin-a) were determined 

from residue on filters.

The capability for load estimates was included in the study 

design. Instantaneous streamflow measurements were made at 

flowing-water sampling locations so that hydrologic conditions 

could be compared. Sampling was done in a synoptic, shortduration time period so that hydrologic conditions would be 

similar. To collect water-supply and effluent samples at their 

facilities during the USGS sampling, IDEM coordinated with 

one municipality and two industries that had permitted outfalls 

in the study area.

SamplingLocations

Previous investigations and a conceptual understanding of 

mercury sources and mercury transport in the study area were 

used to select sampling locations. Among the factors considered 

were

• Water withdrawn from Lake Michigan is discharged 

to the Grand Calumet River/Indiana Harbor Canal 

in noncontact cooling water and treated effluent 

from industries and in treated effluent from municipal 

outfalls. 

• Ground-water discharges through streambed sediments 

along much of the Grand Calumet River and parts 

of the Indiana Harbor Canal during typical flow 

conditions. 

• Wetland density is greatest in two areas along the East 

Branch and West Branch Grand Calumet River where 

potentially larger concentrations of methylmercury 

could be found.

A total of 17 sampling locations on the Grand Calumet 

River/Indiana Harbor Canal and Lake Michigan (fig. 5) were 

selected and are described in downstream order in table 2. Of 

the 14 surface-water sampling locations, 8 locations on the 

Grand Calumet River/Indiana Harbor Canal correspond with 

mercury sampling by the USGS in 1999; 10 locations on the 

Grand Calumet River/Indiana Harbor Canal include 8 stream 

reaches designated in a previous investigation by the USGS to 

estimate chemical loads from ground water to the Grand Calumet River/Indiana Harbor Canal (Willoughby and Siddeeq, 

2001). Five locations on the Grand Calumet River (M19, M14, 

M13, M12, and M9) were near wetlands. Three locations on 

Lake Michigan (IH1, LM1, and LM2) were near industrial 

water-supply intakes. IDEM requested the USGS sample 

treated effluent at three locations—an industrial outfall on 

the Indiana Harbor Canal (IO1) and two municipal outfalls 

on the West Branch Grand Calumet River (MO1 and MO2).
Methods 9 Figure 5. Sampling locations for mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan in Lake County, Indiana, August 2001 and May 2002.

Indiana

Harbor Canal

ILLINOIS

INDIANA

INDIANA

STUDY

AREA

0

0 1

1 2

2

4

4

5

5

3

3

MILES

KILOMETERS

Gary 

Harbor

COOK COUNTY

LAKE COUNTY

Buffington

Harbor

Indiana

Harbor

Gary Airport

M2

M4

M6

M7

M12

M9 M13

M14

M16 M19

M18

IO1

MO2

MO1

LM2

LM1

IH1

SAMPLING LOCATION AND IDENTIFICATION

Base from U.S. Geological Survey digital data, 1:100,000, 1983

Albers equal-area conic projection

Standard parallels 29o 30' and 45o 30', central meridian -86o

M13

Lake Michigan

87o 87 15' 00'' o 30' 00''

41o 40' 00''

41o 37' 30''

APPROXIMATE STREAM REACH AND DESIGNATION (from Willoughby and Siddeeq, 2001)

Wolf 

Lake

Lake

George

B A C D

E

F

G

H

River Grand Calumet

Branch

East

Branch

Grand Calumet 

West

Lake George Canal

D

U.S. GEOLOGICAL SURVEY STREAMFLOW-GAGING STATION AND IDENTIFICATION 05536357

05536357

04092750

EXPLANATION

Grand Calumet 

Lagoons

(west)

(east)

River
10 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 2. Locations for mercury sampling in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, 

August 2001 and May 2002.

[Locations listed in downstream order; reach designations A through H from Willoughby and Siddeeq (2001)—see figure 5; ID, identification; 

M, location in main channel of Grand Calumet River/Indiana Harbor Canal; MO, location at municipal outfall; IO, location at industrial outfall; 

IH, location in Indiana Harbor; LM, location in Lake Michigan]

Location 

ID Location name Location purpose

M19a

a

Mercury sampling location in July 1999 (Stewart and others, 2001).

Grand Calumet Lagoons, west Upstream from all outfalls; wetland area; 

minimal flow.

M18a East Branch Grand Calumet River 

downstream from the Grand Calumet Lagoons, west

Headwaters of East Branch Grand Calumet River; 

upstream from all outfalls; upstream end of Reach A; 

minimal flow.

M16 East Branch Grand Calumet River at Bridge St. Downstream end of reach A; downstream from industrial 

cooling-water and treated process-water outfalls.

M14 East Branch Grand Calumet River at Cline Ave. Near the downstream end of reach B; 

downstream from municipal outfall; wetland area.

M13a East Branch Grand Calumet River at Kennedy Ave. Near the downstream end of reach C; wetland area.

M12a West Branch Grand Calumet River at Hohman Ave. Near the downstream end of reach E; 

upstream from municipal outfalls; wetland area.

MO1 West Branch Grand Calumet River municipal outfall 1 Assessment of municipal effluent.

M9a West Branch Grand Calumet River at Indianapolis Blvd. Near the downstream end of reach D; 

downstream from municipal outfalls; wetland area.

MO2 West Branch Grand Calumet River municipal outfall 2 Assessment of municipal effluent.

M7a Indiana Harbor Canal at Columbus Dr. Near the downstream end of reach F; 

integrates East Branch and West Branch of 

Grand Calumet River.

M6a Indiana Harbor Canal at Lake George Canal Near the downstream end of reach G.

IO1 Indiana Harbor Canal industrial outfall Assessment of industrial effluent.

M4 Indiana Harbor Canal at Dickey Rd. Upstream from industrial outfalls; 

integrates Lake George Canal.

M2a Indiana Harbor Canal at mouth of Indiana Harbor Downstream end of reach H; 

downstream from outfalls on Indiana Harbor Canal; 

confluence of Indiana Harbor Canal with Lake Michigan.

IH1 Indiana Harbor near industrial intake Assessment of water supply for industrial discharge.

LM1 Lake Michigan near industrial intake 1 Assessment of water supply for industrial discharge.

LM2 Lake Michigan near industrial intake 2 Assessment of water supply for industrial discharge.
Methods 11

SamplingProcedures

This section describes the ultra-clean protocols for collection of water and effluent samples for low-level mercury 

analysis, along with the specific equipment, supplies, and 

watercraft that were used. Three types of sampling approaches 

are explained. Methods for mercury analysis and quality control 

are identified.

Equipment and Supplies

Water samples were obtained with a peristaltic-pump 

apparatus (fig. 6). A Teflon weight with intake ports was lowered with a Kevlar hand line to the desired sampling depths. The 

weight was connected to an optimal length of small-diameter 

Teflon tubing inserted in a short piece of silicone flex tubing at 

the pump head. When used, a Teflon filter holder with a preloaded glass-fiber particulate filter was connected to the flex 

tubing. Mercury-sampling supplies were prepared at the USGS 

Mercury Research Laboratory in Wisconsin. Following the 

ultra-clean protocols, the weights, hand lines, and single-use 

sets of sampling supplies3 were decontaminated in a Class 100 

clean room environment, double bagged, and placed in shipping 

containers (Olson and others, 2000). A portable glove box 

was used for sample preservation in the field. The mercurysampling equipment and supplies used were consistent with 

USEPA Method 1669 (U.S. Environmental Protection Agency, 

1996). 

An isokinetic, depth-integrating sampler was used for 

collection of suspended-sediment samples, consistent with 

the USGS National Field Manual (Wilde and Radtke, 1998). 

A portable, multi-parameter electronic meter was used to measure water-quality characteristics (pH, specific conductance, 

dissolved oxygen concentration, and water temperature). A portable turbidimeter (Hach model 2100P) was used to measure 

turbidity. A portable pH meter with temperature compensation 

and a digital titrator were used for alkalinity determinations.

Watercraft and Vehicles

Sample collection on the Grand Calumet River/Indiana 

Harbor Canal, Grand Calumet Lagoons (west), and Indiana 

Harbor was done from an inflatable, rubberized boat with 

wooden floors and transom (fig. 7). The boat was held stationary by a cable tagline stretched across the stream channel and a 

resin-coated anchor. All anchor lines were nylon. Sample collection on Lake Michigan was done from the stern of an 

anchored, fiberglass ship. A mobile water-quality laboratory 

was used to process samples and to complete alkalinity titrations. Watercraft and vehicle procedures were consistent with 

USEPA Method 1669.

Sample Collection

Water samples for total mercury and methylmercury 

analysis were collected by ultra-clean trace-metals protocols 

consistent with the USEPA (1996), Wilde and Radtke (1998), 

and Horowitz and others (1994). Ultra-clean protocols are 

designed to avoid the unintentional introduction of low levels of 

trace metals, such as mercury, into a sample. Two USGS personnel collected samples. To protect sample integrity, sampling 

personnel wore disposable coveralls, hats, face shields, and 

powder-free disposable gloves (fig. 7). 

3Teflon tubing, Teflon bottles, silicone flex tubing and Teflon filter 

holders.

Figure 6. Peristaltic-pump apparatus for mercury sampling, August 2001 and May 2002, in Lake County, Indiana.

Peristaltic pump

Teflon weight with

sample intake ports

Kevlar hand line to 

Teflon tubing raise and lower weight Silicone flex tubing

Teflon filter holder and filter

Teflon sample bottle

Volume-measurement vessel
12 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Figure 7. Watercraft and U.S. Geological Survey personnel during mercury sampling, Lake County, Indiana, August 2001.

Three types of sampling approaches were used to 

collect a representative sample for each location, following 

procedures in Wilde and Radtke (1998). 

1. At locations in the Grand Calumet River/Indiana 

Harbor Canal, depth-integrated composite samples 

were collected at the center of three equal-width 

sections. Stream width was measured with an incremented tagline, and stream depth was determined 

at the center of each section with a weighted measuring tape. At each sampling interval, the pump 

intake was raised and lowered at a constant rate 

until the desired sample volume was obtained. 

2. At locations in the Grand Calumet Lagoons (west), 

Indiana Harbor, and Lake Michigan, samples were 

composited with equal portions from the center 

of three equal-length sections of a single vertical. 

Length of the water column was determined at 

each vertical with a weighted measuring tape. 

3. At locations of effluent outfalls, point samples 

were collected in the center of flow.

The mercury-sampling supplies for a location were sorted 

into plastic boxes inside a larger supply box to isolate them 

from airborne mercury. Repeated glove changes were made so 

that sample bottles were handled only with new gloves. Teflon

bottles provided by the USGS Mercury Research Laboratory 

were pre-cleaned, pre-charged with high-purity 1-percent 

hydrochloric acid, and quality assured as described in the laboratory’s quality-assurance plan. Bottles were shaken, and 

the acid was discarded before filling. For filtered samples, at 

least 1.5 L of sample water were pumped through a 0.45-μm 

pore-size filter—one filter for particulate total mercury analysis 

and another filter for particulate methylmercury analysis. Water 

samples for mercury and methylmercury analysis were kept in 

the dark immediately after collection until they were preserved 

with high-purity hydrochloric acid under controlled conditions 

in a glove box in the mobile laboratory. Filters for particulate 

mercury and methylmercury analysis were frozen on dry ice. 

Table 3 lists containers, treatment, and preservation for mercury 

and supplementary constituents.

Water-QualityAnalysis

Mercury and organic carbon analyses were done by the 

USGS Mercury Research Laboratory. Analysis for total mercury was by "oxidation, purge and trap, and cold vapor atomic 

fluorescence spectrometry" (Olson and DeWild, 1997a), equivalent to USEPA Method 1631 (U.S. Environmental Protection 

Agency, 1999). Analysis for methylmercury was by "aqueous-
Methods 13

Table 3. Constituents, containers, treatment, and preservation for sampling during August 2001 and May 2002 in Lake County, Indiana.

[mL, milliliter; HCl, high-purity hydrochloric acid added to a concentration of 1 percent (%) by volume; μm, micrometer; °C, degree Celsius; < , less than; 

L, liter; ]

Constituent Container Volume Treatment Preservation

Total mercury, unfiltered Teflon, pre-cleaneda

a

Sample containers were 25-percent filled with high-purity 1-percent hydrochloric acid that was discarded before samples were collected.

500 mL None HCl to 1%; keep in darkness.

Methylmercury, unfiltered Teflon, pre-cleaneda 250 mL None HCl to 1%; keep in darkness.

Dissolved total mercury Teflon, pre-cleaneda 500 mL .45-μm quartz-fiber filter HCl to 1%; keep in darkness.

Dissolved methylmercury Teflon, pre-cleaneda 250 mL .45-μm quartz-fiber filter HCl to 1%; keep in darkness.

Particulate total mercury .45-μm quartz-fiber filter None 1.5-L sample per filter Freeze with dry ice immediately.

Particulate methylmercury .45-μm quartz-fiber filter None 1.5-L sample per filter Freeze with dry ice immediately.

Total organic carbon Glass vial, new 40 mL None Chill to 4°C.

Dissolved organic carbon Glass vial, new 40 mL .45-μm capsule filter Chill to 4°C.

Dissolved solids Polyethylene, new 250 mL .45-μm capsule filter Chill to 4°C.

Dissolved chloride, sulfate, 

phosphate, and fluoride

Polyethylene, new 250 mL .45-μm capsule filter Chill to 4°C.

Dissolved calcium, magnesium, 

potassium, sodium, iron, 

silica, and manganese

Polyethylene, new 250 mL .45-μm capsule filter 1 Molar nitric acid to 

pH < 2; chill to 4°C.

Chlorophyll-a, pheophytin-a 

phytoplankton biomass

Three .7-μm glass-fiber 

filters

None 125-mL sample per filter Place in petri dish; wrap in foil; 

freeze with dry ice 

immediately.

Suspended sediment Glass, tared 1 L None None.

phase ethylation and gas chromatography separation with cold 

vapor atomic fluorescence detection" (DeWild and others, 

2002) equivalent to USEPA Method 1630 (U.S. Environmental 

Protection Agency, 1998). All total mercury and methylmercury determinations were made on duplicate aliquots from 

each sample, and concentrations in this report are the averages 

of the duplicate-aliquot analyses. Detection limits for total mercury and methylmercury in groups of samples were determined 

by the laboratory through analysis of calibration standards and 

blanks. Detection limits are listed with the analytical results in 

the appendixes (table 1–1, table 2–1).

Analysis for most supplementary constituents (dissolved 

solids, dissolved major ions, nutrients, and plant pigments) was 

done by the USGS National Water Quality Laboratory in Colorado. Analysis for suspended sediment was done by the USGS 

Northeastern Region Sediment Laboratory in Kentucky. Incremental titrations for calcium-carbonate alkalinity were done in 

the mobile laboratory. Dissolved major ions and nutrients were 

analyzed in approximately half of the water samples selected to 

be representative of the study area. Supplementary constituents 

and analytical methods are listed in table 4. 

QualityControl

Approximately one third of all samples analyzed for mercury were quality-control field-blank samples used to determine 

if mercury was introduced unintentionally into samples. Fieldblank water for mercury analysis was provided by the USGS 

Mercury Research Laboratory. Parts of the sampling apparatus 

were isolated for preparation of field-blank samples, including 

the tubing, filter holder, sample bottle, and blank-water container. Blanks for the tubing and filter holder were pumped from 

the blank-water container with the peristaltic pump. The field 

blank for the sample bottle was poured from the blank-water 

container. Field-blank samples were preserved, handled, and 

transported with the other water samples. Samples of the preservative and blank water were obtained at the Mercury Research 
14 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 4. Analytical methods for supplementary constituents in water samples during August 2001 and May 2002 

in Lake County, Indiana.

[mg/L, milligram per liter; CaCO3, calcium carbonate]

Constituent Analytical method Published reference Reporting limit 

(mg/L)

Chloride Ion chromatography Fishman and Friedman, 1989 0.08

Fluoride Ion-selective electrode Fishman and Friedman, 1989 .16

Sulfate Ion chromatography Fishman and Friedman, 1989 .11

Phosphate, ortho Colorimetry Fishman, 1993 .018

Alkalinity, CaCO3 Incremental titration Wilde and Radtke, 1998 1.0

Calcium Inductively coupled plasma spectrometry Fishman, 1993 .011

Magnesium Inductively coupled plasma spectrometry Fishman, 1993 .008

Sodium Inductively coupled plasma spectrometry Fishman, 1993 .06

Potassium Atomic absorption flame spectrometry Fishman and Friedman, 1989 .09

Silica Colorimetry Fishman and Friedman, 1989 .48

Iron Inductively coupled plasma spectrometry Fishman, 1993 .01

Manganese Inductively coupled plasma spectrometry Fishman, 1993 .0032

Dissolved solids Gravimetric Fishman and Friedman, 1989 10

Organic carbon Heat-assisted persulfate oxidation Olson and DeWild, 1997b .1 

Chlorophyll-a Fluorometry, chromatography Britton and Greeson, 1989 .0001 

Pheophytin-a Fluorometry, chromatography Britton and Greeson, 1989 .0001 

Sestona

a

Ash-free dry weight.

Gravimetric Fishman and Friedman, 1989 .1

Suspended sediment Gravimetric Guy, 1969 1.0

Laboratory from what remained in the containers after use in 

the field. The laboratory also provided analysis of blank water 

not transported to the field. 

Laboratory quality-control samples were prepared and 

analyzed in a manner consistent with USEPA Method 1631 

(U.S. Environmental Protection Agency, 1999). Field and laboratory quality-control data were evaluated according to the 

USEPA Method 1631 and Guidance for Implementation of 

Method 1631 (U.S. Environmental Protection Agency, 2001b).

Field-collected, laboratory-blind, sequential duplicate 

samples were collected to investigate the natural variability 

of constituent concentrations in flowing and still water. The 

duplicate sample was collected immediately following the first 

sample at each of the three horizontal or vertical sections.

Streamflow

Instantaneous streamflow was measured, where flow 

was sufficient, while water samples were collected at sampling 

locations on the Grand Calumet River/Indiana Harbor Canal. 

Acoustic Doppler current profiler (ADCP) methods were used 

in August 2001 at sampling locations M16, M14, M13, and M6 

and in May 2002 at sampling locations M16 and M13. A 1200-

kilohertz ADCP was deployed from a tethered platform, and 

data were collected on a portable field computer with radio 

telemetry. USGS protocols for ADCP measurements (Lipscomb, 1995) were followed; streamflow data were processed, 

checked, and archived. Standard USGS methods for measurement of streamflow (Rantz and others, 1982) were used in 

August 2001 at sampling location M9 and in May 2002 at 
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 15

sampling locations M14 and M9. A Price AA mechanical current meter and 30-lb sounding weight suspended from a bridge 

crane and connected to an electronic discharge-measurement 

interface collected and processed the streamflow data. For 

the 60-minute periods of water sampling at locations M7, 

M4, and M2, streamflow was computed as the mean of four 

15-minute-interval values from USGS streamflow-gaging 

station 04092750. For sampling location M12, the nearest 

hourly instantaneous streamflow value from USGS streamflowgaging station 05536357 on the West Branch Grand Calumet 

River was used. 

Mercury intheGrandCalumetRiver/

IndianaHarborCanalandLakeMichigan

This section describes the results from August 2001 and 

May 2002 for total mercury and methylmercury in the Grand 

Calumet River/Indiana Harbor Canal and Lake Michigan, 

including the quality-control samples. A discussion of the 

relation of streamflow, sampling locations, and water-quality 

constituents to mercury concentrations is presented. Estimated 

loads of total mercury at the time of sampling are presented, and 

mercury concentrations in effluent are summarized. Implications for a mercury TMDL are discussed.

TotalMercuryandMethylmercury

Laboratory determinations of “total mercury” for this 

study included inorganic mercury and methylmercury, although 

methylmercury also was determined separately. In this report, 

total mercury or methylmercury determinations from a filtered 

sample are termed “dissolved total mercury” or “dissolved 

methylmercury.” When the filters were processed at the laboratory and analyzed for total mercury or methylmercury, determinations from a filter are particulate-bound mercury, termed 

“particulate total mercury” or “particulate methylmercury.” 

The sum of dissolved and particulate total mercury concentrations is termed “combined total mercury.” The sum of dissolved 

and particulate methylmercury is termed “combined methylmercury.” When dissolved methylmercury was not detected, 

the combined methylmercury is assumed to be equivalent to the 

particulate methylmercury. Total mercury or methylmercury 

determinations from an unfiltered sample are termed “unfiltered 

total mercury” or “unfiltered methylmercury.” 

Samples collected during August 2001 from the Grand 

Calumet River/Indiana Harbor Canal and Lake Michigan were 

analyzed for dissolved and particulate total mercury and dissolved and particulate methylmercury; effluent samples were 

analyzed for unfiltered total mercury. Samples collected during 

May 2002 from the Grand Calumet River/Indiana Harbor Canal 

and Lake Michigan were analyzed for dissolved and particulate 

total mercury; effluent samples were analyzed for unfiltered 

total mercury. All of the 2002 samples were analyzed for unfiltered methylmercury. Because dissolved methylmercury 

was not detected in 13 of the 14 samples for 2001 (appendix: 

table 1–1), 5 samples were analyzed for dissolved and particulate methylmercury in 2002.

Mercury concentrations listed in the appendixes and 

discussed in this section are mean values from analysis of duplicate aliquots from each sample bottle. For sampling locations 

with field-duplicate samples, the largest concentration is used 

to report the maximum range of concentrations and to estimate 

the maximum instantaneous mercury load; these values may 

be more relevant to application of the data in a TMDL. Both 

concentrations from field-duplicate samples are used in the discussion of natural variability in the section, Factors Affecting 

Mercury Concentrations and Mercury Transport. Combined 

total mercury and combined methylmercury concentrations 

are used in discussions of samples collected during 2001 and 

2002. For sampling locations from 2002 without combined 

methylmercury concentrations, the unfiltered methylmercury 

concentration was substituted.

Mercury inEnvironmentalSamples

Ranges of combined total mercury and methylmercury 

concentrations in water samples from groups of sampling locations are presented in table 5. The largest combined total mercury concentrations during August 2001 (appendix: table 1–1) 

were in the Indiana Harbor Canal near the confluence of the 

East Branch and West Branch Grand Calumet River (M7, 

16.0 ng/L) and in the West Branch Grand Calumet River near 

wetlands and municipal-effluent outfalls (M9, 15.9 ng/L). 

The largest combined total mercury concentration during 

May 2002 (appendix: table 2–1) was in the West Branch Grand 

Calumet River near wetlands (M12, 17.2 ng/L). The largest 

combined methylmercury concentrations were in the West 

Branch Grand Calumet River during August 2001 (M12, 

0.091 ng/L; M9, 0.050 ng/L) and during May 2002 (M12, 

0.181 ng/L; M9, 0.147 ng/L). Combined methylmercury as 

a percentage of the combined total mercury concentration 

was as large as 1.5 percent during August 2001 and 6.2 percent 

during May 2002 (table 6).

During August 2001 (fig. 8), the combined total mercury 

concentrations in all samples from the Grand Calumet River/

Indiana Harbor Canal exceeded the Indiana water-quality 

standard of 1.3 ng/L for waters in the Great Lakes system; the 

mean concentration was 5.89 ng/L. Combined total mercury 

concentrations at three locations in Lake Michigan (maximum 

0.34 ng/L) were less than the standard. The maximum concentration in the West Branch Grand Calumet River (15.9 ng/L at 

M9) was larger than the maximum concentration in the East 

Branch Grand Calumet River (5.2 ng/L at M16) and similar 
16 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 5. Ranges of combined total mercury and methylmercury concentrations in water samples from groups 

of sampling locations on the Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, 

Indiana, August 2001 and May 2002.

[Concentrations of mercury in nanogram per liter (ng/L); IDs, identifications; < , less than reporting limit listed]

Group of sampling locations 

and location IDs

Ranges of combined 

total mercury concentrationsa

a

Combined total mercury is the sum of dissolved and particulate concentrations.

b

Combined methylmercury is the sum of dissolved and particulate concentrations. Unfiltered methylmercury concentrations assumed equivalent to combined methylmercury at selected locations during May 2002.

Ranges of combined 

methylmercury concentrationsb

August 2001 May 2002 August 2001 May 2002

East Branch Grand Calumet River 

(M18, M16, M14, M13)

2.56 - 5.25 1.63 - 7.25 0.008 - 0.013 <0.002 - 0.117

West Branch Grand Calumet River 

(M12, M9)

6.30 - 15.9 5.48 - 17.2 .050 - .091 .147 - .181

Indiana Harbor Canal 

(M7, M6, M4, M2)

2.28 - 16.0 4.38 - 6.87 .010 - .024 <.002 - .068

Grand Calumet Lagoons, west 

(M19)

3.17 3.21 .030 .046

Lake Michigan near water intakes 

(IH1, LM1, LM2)

 .18 - .34 1.31 - 3.06 .001 - .004 <.002 - .004

Table 6. Ranges of combined methylmercury as a percentage of combined 

total mercury in water samples from groups of sampling locations on the 

Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, 

Indiana, August 2001 and May 2002.

[IDs, identifications]

Group of sampling locations 

and location IDs

Combined methylmercury 

as a percentage of 

combined total mercury 

concentrationa

a

Combined total mercury and combined methylmercury is the sum of dissolved 

and particulate concentrations. Unfiltered methylmercury concentrations assumed 

equivalent to combined methylmercury at selected locations during May 2002.

August 2001 May 2002

East Branch Grand Calumet River 

(M18, M16, M14, M13)

0.2 - 0.5 0 - 6.2

West Branch Grand Calumet River 

(M12, M9)

.4 - 1.4 1.1 - 2.7

Indiana Harbor Canal 

(M7, M6, M4, M2)

.1 - .4 0 - 1.2

Grand Calumet Lagoons, west 

(M19)

.9 1.4 

Lake Michigan near water intakes 

(IH1, LM1, LM2)

.6 - 1.5 0 - .3
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 17 Figure 8. Combined total mercury concentrations in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan in Lake County, Indiana, August 2001 and May 2002. Grand Calumet River

East

Branch

Indiana

Harbor Canal

ILLINOIS

INDIANA

INDIANA

STUDY

AREA

0

0 1

1 2

2

4

4

5

5

3

3

MILES

KILOMETERS

Gary 

Harbor

COOK COUNTY

LAKE COUNTY

Buffington

Harbor

Indiana

Harbor

Gary Airport

Base from U.S. Geological Survey digital data, 1:100,000, 1983

Albers equal-area conic projection

Standard parallels 29o 30' and 45o 30', central meridian -86o

Lake Michigan

87o 87 15' 00'' o 30' 00''

41o 40' 00''

41o 37' 30''

Wolf 

Lake

Lake

George

6.3

17.2

15.9

5.5

16.0

5.8

4.0

4.7 2.7

7.2 5.2

1.6

0.34

1.3

2.6

1.9

3.2

3.2

7.6

6.4

2.3

4.4

0.26

2.1

0.18

3.1

3.4

6.9

SAMPLING LOCATION

SAMPLING-LOCATION IDENTIFICATION

COMBINED TOTAL MERCURY CONCENTRATION (DISSOLVED AND PARTICULATE, IN NANOGRAMS PER LITER), AUGUST 2001

COMBINED TOTAL MERCURY CONCENTRATION (DISSOLVED AND PARTICULATE, IN NANOGRAMS PER LITER), MAY 2002

IH1

M2

M4

M7

M12

M9 M13

M14

M16 M18

M19

LM2

LM1

M6

Lake George Canal

Branch Grand Calumet

River

West

EXPLANATION

Grand Calumet 

Lagoons

(west)

(east)

6.3

17.2

M12
18 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

to the maximum concentration in the Indiana Harbor Canal 

(16.0 ng/L at M7). The proportion of combined total mercury as 

combined methylmercury was less than 0.5 percent in the Grand 

Calumet River/Indiana Harbor Canal, with the exception of 

M19 (0.9 percent) and M12 (1.4 percent). The largest proportion was in Lake Michigan—1.5 percent at LM1 (appendix: 

table 1–1).

During May 2002 (fig. 8), the combined total mercury 

concentrations in all samples from the Grand Calumet River/

Indiana Harbor Canal exceeded the Indiana water-quality 

standard of 1.3 ng/L; the mean concentration was 6.28 ng/L. 

Combined total mercury at three locations in Lake Michigan 

was equal to or greater than the standard (1.3–3.1 ng/L). The 

maximum concentration in the West Branch Grand Calumet 

River (17.2 ng/L at M12) was larger than the maximum concentration in the East Branch Grand Calumet River (7.2 ng/L at 

M14) and the Indiana Harbor Canal (6.9 ng/L at M6). The proportion of combined total mercury as combined methylmercury 

in the Grand Calumet River/Indiana Harbor Canal generally 

was largest in the East Branch Grand Calumet River headwaters 

(6.2 percent at M18) and the West Branch Grand Calumet River 

(2.7 percent at M9) (appendix: table 2–1).

Most of the combined total mercury in the Grand Calumet 

River/Indiana Harbor Canal and Lake Michigan samples 

was particulate during August 2001 and May 2002 (table 7), 

with the exception of one sample from the Grand Calumet 

Lagoons, west, in 2001 and one sample from Lake Michigan 

in 2002 (appendixes: table 1–1, table 2–1). Particulate methylmercury was detected in all samples for which it was analyzed 

during August 2001 and May 2002.

Combined total mercury and methylmercury concentrations in the Grand Calumet River/Indiana Harbor Canal were 

significantly larger than those in Lake Michigan during August 

2001 and May 2002 (Wilcoxon-Mann-Whitney rank-sum test, 

p = 0.0001 for total mercury; p = 0.004 for methylmercury)4. 

Total mercury concentrations during August 2001 were not 

significantly different than those during May 2002 (WilcoxonMann-Whitney rank-sum test, p= 0.30), but methylmercury 

concentrations during May 2002 were significantly larger than 

those during August 2001 (Wilcoxon-Mann-Whitney rank-sum 

test, p = 0.001). 

Mercury inQuality-Control Field-BlankSamples

Quality-control field-blank samples were prepared before 

and after collecting groups of water samples from the Grand 

Calumet River/Indiana Harbor Canal and Lake Michigan. 

During 2001, five field-blank samples were prepared, and 

analyses detected dissolved total mercury (appendix: table 1–

5). The field blanks5 indicated approximately 0.27 ng/L total 

mercury in some water samples potentially was from collection, 

handling, transport, or storage. Dissolved total mercury concentrations were less than five times that of the field blanks6

(1.35 ng/L) in 11 samples collected during 2001; dissolved 

concentrations were not used to compute combined total 

mercury in these 11 samples (appendix: table 1–1). During 

2002, six field-blank samples were prepared, and analyses 

detected total mercury (appendix: table 2–5). The field blanks 

indicated approximately 0.02 ng/L total mercury potentially 

was from collection, handling, transport, or storage. Total mercury concentrations were more than five times that of the field 

blanks (0.1 ng/L) in every sample; all the dissolved and particulate total mercury concentrations were used to compute 

combined total mercury in these samples for 2002 (appendix: 

table 2–1).

Table 7. Ranges of particulate total mercury as a percentage of 

combined total mercury in water samples from groups of sampling 

locations on the Grand Calumet River/Indiana Harbor Canal and 

Lake Michigan, Lake County, Indiana, August 2001 and May 2002.

[IDs, identifications]

4

The Wilcoxon-Mann-Whitney rank-sum test (Helsel and Hirsch, 1995) 

is a nonparametric procedure used to evaluate the distributions of values in two 

groups. In this statistical analysis, a significance level of 0.05 or less was used 

to accept a statistical difference in the distributions. The p-value is the significance level attained by the data—the smaller the p-value, the more believable 

the statistical difference.

5

Data from field blanks used according to U.S. Environmental Protection 

Agency (2001b). 6

Sample concentrations less than five times field-blank concentrations are 

rejected for use in enforcement of water-quality standards (Indiana Department 

of Environmental Management, Office of Water Quality, Chemistry Section, 

written commun., 2001); 0.27 ng/L multiplied by 5 equals 1.35 ng/L.

Group of sampling locations 

and location IDs

Particulate total mercury 

as a percentage of 

combined total mercurya

in water samples

 August 2001 May 2002

a

Combined total mercury computed as the sum of dissolved mercury and 

particulate mercury concentration in a water sample, compared with the particulate total mercury measured in that same sample.

East Branch Grand Calumet River 

(M18, M16, M14, M13)

100 66.2 - 94.8

West Branch Grand Calumet River 

(M12, M9)

 88.8 - 100 76.6 - 89.8

Indiana Harbor Canal 

(M7, M6, M4, M2)

100 86.0 - 88.6

Grand Calumet Lagoons, west 

(M19)

 26.2 80.6

Lake Michigan near water intakes 

(IH1, LM1, LM2)

100 47.3 - 85.9
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 19

FactorsAffectingMercuryConcentrationsand

MercuryTransport

This section discusses factors affecting mercury concentrations and mercury transport in the study area. Contrasts in 

the weather and streamflow between the two sampling periods 

are described. The relations of suspended sediment, suspended 

fine particulates, and water-quality constituents to mercury 

concentrations are discussed. Natural variability in mercury 

concentrations is examined. 

Weather and Streamflow

The study was designed to provide contrasts in weather 

and streamflow between August 2001 and May 2002 to identify 

potential seasonal differences in mercury and methylmercury in 

the Grand Calumet River/Indiana Harbor Canal. As intended, 

the two sampling periods differed in weather and streamflow.

During sampling in August 2001, weather generally was 

dry and warm; during sampling in May 2002, weather generally 

was wet and cool. Records from the weather station at the Indiana Dunes National Lakeshore approximately 10 mi east of the 

study area (Louis Brenan, National Park Service, 2002, written 

commun.) were used to summarize weather conditions. Samples were collected August 21–24 and August 28–29, 2001, 

from the Grand Calumet River/Indiana Harbor Canal. At 

the Indiana Dunes National Lakeshore, 0.28 in. of rain was 

recorded August 21–24; no rain fell August 28–29, 2001. The 

mean air temperature at the Indiana Dunes National Lakeshore 

weather station August 21–29, 2001, was 22.2°C (71.9°F) and 

ranged from 13.9 to 30.5°C (57–86.9°F). Samples were collected May 6–9 and May 15, 2002, from the Grand Calumet 

River/Indiana Harbor Canal. At the Indiana Dunes National 

Lakeshore, 2.1 in. of rain were recorded May 6–9; 2.6 in. of 

rain were recorded May 12–15, 2002, even though May 15 was 

dry. The mean air temperature at the Indiana Dunes National 

Lakeshore weather station May 6–15, 2002, was 12.2°C 

(53.9°F) and ranged from 4.4 to 23.4°C (39.9–74.1°F). The 

mean water temperatures measured at sampling locations on 

the Grand Calumet River/Indiana Harbor Canal were 26.5°C, 

August 21–29, 2001, and 16.4°C, May 6–15, 2002.

Streamflow during the time of sampling at six of nine 

locations on the Grand Calumet River/Indiana Harbor Canal 

(table 8) was greater in May 2002 than in August 2001. A 

statistical difference in the distribution of streamflow values 

was not observed for 2001 and 2002 (Wilcoxon-Mann-Whitney 

rank-sum test, p = 0.14). 

Suspended Sediment and 

Suspended Fine Particulates

Suspended sediment and suspended fine particulates were 

determined in this study because they could be related to particulate mercury transport in the Grand Calumet River/Indiana 

Harbor Canal. Organic carbon and plant pigments were determined to estimate the composition of the suspended sediment 

and suspended fine particulates.

In the Indiana Harbor Canal study by Renn (2000), the 

mean suspended-sediment concentration for 1,856 samples 

from 1996 through 1998 was 15 mg/L and the range was 1 to 

97 mg/L. Mean suspended-sediment concentration in the Grand 

Calumet River/Indiana Harbor Canal was 11.4 mg/L in August 

2001 and 15.8 mg/L in May 2002. The maximum values in 

August 2001 (45.3 mg/L; table 8) and May 2002 (32.2 mg/L; 

table 8) were less than the 97 mg/L maximum for 1996 through 

1998. 

The mean suspended-sediment concentration in water 

samples from sampling locations on the Grand Calumet River/

Indiana Harbor Canal (table 8) was larger in May 2002 

(15.8 mg/L) than in August 2001 (11.4 mg/L). The suspendedsediment concentrations at 7 of 10 sampling locations on the 

Grand Calumet River/Indiana Harbor Canal were larger in May 

2002 than in August 2001. A statistical difference in the distributions of suspended-sediment concentrations in the Grand 

Calumet River/Indiana Harbor Canal was noted between 2001 

and 2002 but at a 0.06 level of significance (Wilcoxon-MannWhitney rank-sum test, p = 0.06). 

The variability of suspended-sediment concentrations in 

the Grand Calumet River/Indiana Harbor Canal was demonstrated in sequential duplicate samples collected at multiple 

verticals across the stream channel at five sampling locations 

in May 2002 (table 9). Suspended-sediment concentrations 

differed by 2.0 to 54.1 mg/L and the relative percent difference 

(RPD) was 19 to 132 percent. Another indication of variability 

in suspended-sediment concentrations was that sequential 

duplicate samples from location M13 on the East Branch Grand 

Calumet River in August 2001 differed by 3.7 mg/L, a RPD of 

49 percent (appendix: table 1–6).

Suspended-sediment concentrations in water samples 

from the study area were determined from solids retained on a 

1.5-μm pore-size filter. Seston concentrations in water samples 

from the study area were determined from the ash-free dry 

weight of solids retained on a 0.7-μm pore-size filter. Seston 

includes suspended sediments that are solids larger than 1.5 μm 

and suspended fine particulates that are solids from 0.7 to 

1.5 μm. Suspended-fine-particulate concentrations were computed as the difference of seston and suspended-sediment 

concentrations (appendixes: table 1–3, table 2–3). The proportion of suspended fine particulates of the seston in the water 

samples from the Grand Calumet River/Indiana Harbor Canal 

in 2001 and 2002 averaged 11 percent (table 10); no fine particulates were measured in most of the samples. 
20 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 8. Streamflow at 10 sampling locations and suspended-sediment concentration in 

water samples, Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, 

August 2001 and May 2002.

[ID, identification; ft3/s, cubic foot per second; mg/L, milligram per liter; GCR, Grand Calumet River; 

-- , no data]

Sampling location and ID 

Streamflow 

(ft3

/s) 

Suspended-sediment 

concentration 

(mg/L)

August 

2001

May 

2002

August 

2001

May 

2002

M18 East Branch GCR -- -- 8.5 21.6

M16 East Branch GCR 467 446 13.2 7.2

M14 East Branch GCR 529 540 7.1 13.6

M13 East Branch GCR 691 629 9.4 32.1

M12 West Branch GCR 7.9 40 4.7 13.7

M9 West Branch GCR 44.6 159 45.3 12.4

M7 Indiana Harbor Canal 431 580 10.9 15.1

M6 Indiana Harbor Canal 94.2 -- 3.2 5.3

M4 Indiana Harbor Canal 551 834 6.2 32.2

M2 Indiana Harbor Canal 578 782 5.8 4.8

Mean 377 501 11.4 15.8

Table 9. Suspended-sediment concentrations in sequential duplicate water samples from 

five sampling locations on the Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, 

May 2002.

[mg/L, milligram per liter; ID, identification; RPD, relative percent difference; GCR, Grand Calumet River; 

-- , no data]

Suspended-sediment concentration 

(mg/L)

Sampling location and ID Vertical 1 Vertical 2 Vertical 3 Maximum 

differencea

a

Maximum difference of concentrations computed by subtracting smallest concentration from largest concentration.

RPDb

b

Relative percent difference computed as difference between concentrations divided by the average, 

multiplied by 100.

M16 East Branch GCR 7.1 6.3 8.3 2.0 27

M14 East Branch GCR 12.5 15.2 -- 2.7 19

M13 East Branch GCR 67.9 18.0 13.8 54.1 132

M9 West Branch GCR 14.2 11.0 -- 3.2 25

M7 Indiana Harbor Canal 20.0 18.0 5.5 14.5 114
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 21

Table 10. Proportions of suspended fine particulates, particulate organic carbon, and plant pigments (chlorophyll-a and 

pheophytin-a) in seston of water samples from groups of sampling locations on the Grand Calumet River/Indiana Harbor 

Canal, Lake County, Indiana, August 2001 and May 2002.

[IDs, identifications; -- , no data]

Group of sampling locations 

and location IDs

Proportion 

of 

suspended fine 

particulates 

(percent)

Proportion 

of 

particulate organic carbon 

(percent)

Proportion 

of 

plant pigments 

(percent)

August 

2001

May 

2002

August 

2001

May 

2002

August 

2001

May 

2002

East Branch Grand Calumet River 

(M18, M16, M14, M13)

0 - 37 0 - 13 0.38 - 2.5 0.80 - 1.3 0.02 - 0.07 0.03 - 0.29

West Branch Grand Calumet River 

(M12, M9)

0 - 61 0 - 5 .35 - 1.5 .20 - 1.2 .03 - .33 .08

Indiana Harbor Canal 

(M7, M6, M4, M2)

0 0 - 35 4.3 0 - 15 .02 .04 - .09

Grand Calumet Lagoons, west 

(M19)

-- 0 -- 1.1 -- .15

Mean (all locations, 2001 and 2002) 11 2.1 .08

The seston could include inorganic and organic solids. 

The proportion of organic solids in the seston was estimated 

with the concentration of particulate organic carbon. Particulate organic carbon was computed as the difference of total and 

dissolved organic carbon in water samples from the study area 

(appendixes: table 1–3, table 2–3). The proportion of particulate organic carbon in the seston of the water samples from the 

Grand Calumet River/Indiana Harbor Canal in 2001 and 2002 

averaged 2.1 percent (table 10). The highest proportion of 

particulate organic carbon (15 percent) was in the May 2002 

sample from M2 in the Indiana Harbor.

The particulate organic carbon could include plants 

and animals (phytoplankton and zooplankton) and nonliving 

carbon. An estimate of the plant matter in the seston was 

made with the sum of the concentrations of two plant pigments 

(chlorophyll-a and pheophytin-a) from water samples in the 

study area. The proportion of these two plant pigments in 

the seston of the water samples from the Grand Calumet River/ 

Indiana Harbor Canal averaged 0.08 percent (table 10). 

The highest proportion of plant pigment in the seston was 

0.33 percent in the August 2001 sample from M12 in the West 

Branch Grand Calumet River and 0.29 percent in the May 2002 

sample from M18 in the East Branch Grand Calumet River 

(table 10).

With these data, the estimated composition of most 

of the suspended solids in the water samples from the Grand 

Calumet River/Indiana Harbor Canal was sediment larger than 

1.5 μm containing approximately 2 percent particulate organic 

carbon and less than 0.1 percent plant pigment. Sediment 

larger than 1.5 μm includes medium clay, silt, and sand 

(Horowitz, 1991).

Natural Variability of Mercury Concentrations

Natural variability of mercury concentrations was demonstrated with 18 total mercury and 9 methylmercury sequential 

duplicate samples (appendixes: table 1–6, table 2–6). Relative 

percent difference7 (RPD) was used to quantify the natural 

variability. Among the duplicate samples from the Grand 

Calumet River/Indiana Harbor Canal and Lake Michigan, 

dissolved total mercury concentrations varied as much as 

75.4 percent (median, 44.2 percent); particulate total mercury 

varied as much as 155.6 percent (median, 24.1 percent); 

and unfiltered total mercury varied as much as 8.9 percent 

(median, 2.8 percent). Particulate methylmercury varied as 

much as 46.2 percent (median, 6.5 percent), and unfiltered 

methylmercury varied as much as 20.6 percent (median, 

9.3 percent).

7

Relative percent difference (RPD) is a percentage computed by subtracting one concentration from the other and dividing the difference by 

the average of the two concentrations, then multiplying by 100 to obtain 

a percentage.
22 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

The combined and particulate total mercury concentrations in the Grand Calumet River/Indiana Harbor Canal in 

2001 and 2002 were not correlated to suspended-sediment 

concentrations (Kendall’s tau correlation coefficient, p = 0.38 

for combined total mercury; p = 0.59 for particulate total 

mercury).8

The natural variability of mercury in water from the study 

area should be considered when single samples or small data 

sets are evaluated without duplicate samples for comparison. 

It is possible that the distribution of suspended sediment 

and suspended fine particulates (horizontally and vertically 

in the channel of the Grand Calumet River/Indiana Harbor 

Canal or vertically in the Grand Calumet Lagoons, west, or 

Lake Michigan) contributed to the variability of total mercury 

and methylmercury concentrations in duplicate samples.

Water-Quality Constituents

The largest values of water-quality characteristics and 

largest concentrations of major ions and nutrients generally 

were measured in samples from the West Branch Grand Calumet River at sites M9 and M12 and from the East Branch Grand 

Calumet River headwaters at site M18 (appendixes: table 1–3, 

table 2–3). The range and maximum concentrations of dissolved solids, total organic carbon, and sulfate are summarized 

in table 11. Combined total mercury concentrations in 2001 

and 2002 were not significantly correlated to concentrations of 

dissolved solids, total organic carbon, or sulfate (Kendall’s tau 

correlation coefficient, p = 0.16 for dissolved solids; p = 0.38 

for total organic carbon; p = 0.35 for dissolved organic carbon; 

p = 0.40 for sulfate). Combined methylmercury concentrations 

in 2001 and 2002, however, were significantly correlated to 

dissolved solids, total organic carbon, and sulfate (Kendall’s 

tau correlation coefficient, p = 0.0008 for dissolved solids; 

p = 0.004 for total organic carbon; p = 0.0006 for dissolved 

organic carbon; p = 0.02 for sulfate).

TotalMercury Loads

Total mercury loads during the time of sampling were 

estimated with the combined total mercury concentrations in 

water samples and instantaneous streamflow values concurrent 

with the hour of water-sample collection at eight locations with 

streamflow data. Table 12 presents the estimated combined 

total mercury loads (mg/hr) for the East Branch and West 

Branch Grand Calumet River and the Indiana Harbor Canal in 

the study area during August 2001 and May 2002. Estimated 

instantaneous mercury loads in the Indiana Harbor Canal were 

as large as 703 mg/hr in August 2001 and 542 mg/hr in May 

2002 (fig. 9). The largest loads were in the Indiana Harbor 

Canal and in the East Branch Grand Calumet River because of 

more streamflow. Generally, the loads in the Indiana Harbor 

Canal decreased between M7 and M2 or M4 and M2, indicating 

that mercury may be deposited with streambed sediment, corresponding to decreases in particulate mercury concentrations 

(appendixes: table 1–1, table 2–1). A statistical difference was 

not observed between estimated total mercury loads in August 

2001 and May 2002 (Wilcoxon-Mann-Whitney rank-sum 

test, p = 0.68). Data for the load estimates are in the appendixes 

(table 1–2, table 2–2).

8

The Kendall’s tau correlation coefficient (Helsel and Hirsch, 1995) 

is a nonparametric, rank-based procedure to evaluate the relation between two 

variables. In this statistical analysis, a significance level of 0.05 or less was 

used to accept a statistical relation between the two variables. The p-value is 

the significance level attained by the data—the smaller the p-value, the more 

believable the statistical relation.

Table 11. Ranges of concentrations of dissolved solids, total organic carbon, and sulfate in water samples from groups of sampling 

locations on the Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, August 2001 and May 2002.

[Concentrations in milligram per liter, mg/L; IDs, identifications; -- , no data]

Group of sampling locations 

and location IDs

Dissolved solids Total organic carbon Sulfate

2001 2002 2001 2002 2001 2002

East Branch Grand Calumet River 

(M18, M16, M14, M13)

216 - 558 206 - 504 2.56 - 8.54 2.12 - 6.81 28.7 - 169 29.8 - 125

West Branch Grand Calumet River 

(M12, M9)

448 - 818 304 - 492 7.28 - 8.26 6.47 - 6.85 209 - 248 96.3

Indiana Harbor Canal 

(M7, M6, M4, M2)

194 - 292 254 - 412 2.20 - 3.10 3.32 - 5.24 54.3 42.8 - 63.0

Grand Calumet Lagoons, west 

(M19)

-- 400 10.6 6.65 -- 73.2

Lake Michigan near water intakes 

(IH1, LM1, LM2)

166 - 202 172 - 221 1.92 - 2.52 1.94 - 6.49 -- --
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 23 Figure 9. Estimated loads of combined total mercury during the time of sampling at selected locations in the Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, August 2001 and May 2002. River Grand Calumet

East

Branch

Indiana Harbor Canal

ILLINOIS

INDIANA

INDIANA

STUDY

AREA

0

0 1

1 2

2

4

4

5

5

3

3

MILES

KILOMETERS

Gary 

Harbor

COOK COUNTY

LAKE COUNTY

Buffington

Harbor

Indiana

Harbor

Gary Airport

Base from U.S. Geological Survey digital data, 1:100,000, 1983

Albers equal-area conic projection

Standard parallels 29o 30' and 45o 30', central meridian -86o

Lake Michigan

87o 87 15' 00'' o 30' 00''

41o 40' 00''

41o 37' 30''

Wolf 

Lake

Lake

George

5.07

70.0

72.2

88.8

703

341

279

304 147

399 250

74.1

425

542

134

349

72.2

88.8

SAMPLING LOCATION

SAMPLING-LOCATION IDENTIFICATION

ESTIMATED COMBINED TOTAL MERCURY LOAD (DISSOLVED AND PARTICULATE, IN MILLIGRAMS PER HOUR), AUGUST 2001

ESTIMATED COMBINED TOTAL MERCURY LOAD (DISSOLVED AND PARTICULATE, IN MILLIGRAMS PER HOUR), MAY 2002

M4

M2

M7

M9

M12

M13

M14

M16

M9

River

Grand Calumet

Branch

West

Lake George Canal

EXPLANATION

Grand Calumet 

Lagoons

(west)

(east)
24 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 12. Estimated loads of combined total mercury during the 

time of sampling at eight sampling locations on the Grand Calumet 

River/Indiana Harbor Canal, Lake County, Indiana, August 2001 

and May 2002.

[mg/hr, milligram per hour; ID, identification; GCR, Grand Calumet River]

Implications foraTotalMaximumDaily Load

Data from this study have implications for a Total Maximum Daily Load for mercury in the Grand Calumet River/ 

Indiana Harbor Canal. Comparisons of data from this study 

with historical data show consistency in a longer time scale. 

Mercury in effluent samples indicate potential mercury inputs 

that could be controlled to achieve a TMDL. Mercury in 

ground-water discharge may be difficult to control to achieve a 

TMDL because of its diffuse and widespread distribution. Other 

inputs of mercury to a TMDL are described in this section of the 

report. 

Generally, the combined total mercury loads in the Indiana Harbor Canal decreased as water flowed toward Lake 

Michigan. The largest concentrations of methylmercury and 

proportions of total mercury as methylmercury in samples from 

the East Branch and West Branch Grand Calumet River and 

in samples from the municipal outfalls on the West Branch 

Grand Calumet River appear to be related to the location of 

the wetlands.

Comparisons with Historical Data 

Total mercury concentrations (table 13) in water samples 

collected from the Grand Calumet River/Indiana Harbor Canal 

by the USGS in July 1999 generally were similar to those 

collected in August 2001 and May 2002 (Kruskal-Wallis ranksum test, p = 0.95).9

 Larger concentrations were measured 

in the West Branch Grand Calumet River (M9 and M12) than in 

the East Branch; the overall range of concentrations were similar for all 3 years. 

In comparison with the Lake Michigan Mass Balance 

Study in 1994 and 1995, the data from 2001 and 2002 in this 

study had several similarities: (a) mercury concentrations in 

the Grand Calumet River/Indiana Harbor Canal were larger 

than those in Lake Michigan; (b) mercury concentrations in 

the Grand Calumet River/Indiana Harbor Canal exceeded the 

standard, but those in Lake Michigan did not; (c) mercury was 

predominantly particulate. These data do not indicate substantial changes in the distribution of mercury in the study area from 

1994 through 2002.

Table 13. Concentrations of total mercury in water samples from 

seven sampling locations on the Grand Calumet River/Indiana 

Harbor Canal, Lake County, Indiana, July 1999, August 2001, and 

May 2002.

[Concentrations in nanogram per liter (ng/L); ID, identification; GCR, Grand 

Calumet River]

Mercury in Effluent Samples 

During August 2001 and May 2002, unfiltered mercury 

concentrations in treated effluent samples collected by the 

USGS exceeded the Indiana water-quality standard of 1.3 ng/L 

for waters in the Great Lakes system at the municipal outfall 

Estimated load 

of combined total mercurya

(mg/hr)

a

Combined total mercury concentrations are a sum of dissolved 

and particulate concentrations.

Sampling location and ID August 

2001

May 

2002

M16 East Branch GCR 250 74.1

M14 East Branch GCR 147 399

M13 East Branch GCR 279 304

M12 West Branch GCR 5.07 70.0

M9 West Branch GCR 72.2 88.8

M7 Indiana Harbor Canal 703 341

M4 Indiana Harbor Canal 425 542

M2 Indiana Harbor Canal 134 349

9

The Kruskal-Wallis rank-sum test (Helsel and Hirsch, 1995) is a nonparametric procedure to evaluate if the distributions of the three groups are 

different. A significance level of 0.05 or less was used to accept a statistical 

difference in the distributions of the three groups. The p-value is the significance attained by the data—the smaller the p-value, the more believable the 

statistical difference.

Sampling location and ID July 

1999a

a

Total mercury concentration in unfiltered sample.

b

Sum of dissolved and particulate total mercury concentrations.

August 

2001b

May 

2002b

M18 East Branch GCR 7.39 2.56 1.89

M13 East Branch GCR 3.31 3.96 4.74

M12 West Branch GCR 6.23 6.30 17.2

M9 West Branch GCR 19.0 15.9 5.48

M7 Indiana Harbor Canal 5.18 16.0 5.76

M6 Indiana Harbor Canal 2.06 3.42 6.87

M2 Indiana Harbor Canal 3.11 2.28 4.38
Mercury in the Grand Calumet River/ Indiana Harbor Canal and Lake Michigan 25

MO2 (10.8 and 2.48 ng/L) and the Indiana Harbor Canal industrial outfall IO1 (2.00 and 3.71 ng/L); the Indiana water-quality 

standard was not exceeded at the municipal outfall MO1 

(0.60 and 1.08 ng/L). Mercury concentrations in sequential 

duplicate effluent samples varied as much as 121 percent 

(median, 27.3 percent) (appendixes: tables 1–4 and 1–6, tables 

2–4 and 2–6). 

IDEM provided total mercury data for unfiltered grab samples from effluent outfalls and water intakes at two industries 

and one municipality in the study area (Kathy Luther, Indiana 

Department of Environmental Management, written commun., 

February 2002, February 2003). These samples were collected 

at the same time as the USGS samples in 2001 and 2002. 

In the data from IDEM for 2001 and 2002, the mean total 

mercury concentrations in effluent samples were (a) 1.0 ng/L 

in 2001 from 12 industrial outfalls and 2.5 ng/L in 2002 from 

4 industrial outfalls on the East Branch Grand Calumet River; 

(b) 0.72 ng/L in 2001 from 4 industrial outfalls on the Indiana 

Harbor Canal; and (c) 1.8 ng/L in 2001 and 12.2 ng/L in 2002 

from 1 municipal outfall on the East Branch Grand Calumet 

River. Also, the mean mercury concentrations in samples 

from the water-supply intakes were (a) 0.69 ng/L in 2001 

and 1.0 ng/L in 2002 for the industrial outfalls on the East 

Branch Grand Calumet River, and (b) 0.32 ng/L in 2001 

for the industrial outfalls on the Indiana Harbor Canal. (The 

USGS data for mercury in Lake Michigan near these intakes 

[LM1, LM2; appendixes: tables 1–1, 2–1] ranged from 0.26 

to 2.10 ng/L).

The effluent and water-intake data indicated mercury 

concentrations in industrial and municipal effluent could exceed the Indiana water-quality standard, even when the intake 

water from Lake Michigan contained mercury concentrations 

less than the standard. Also, mercury concentrations in municipal effluents were larger and more variable than those in 

industrial effluent, presenting a potential for larger mercury 

loads, based on concentration.

Mercury in Ground-Water Discharge

Willoughby and Siddeeq (2001) estimated the maximum 

loads of mercury in ground water discharging to eight reaches 

of the Grand Calumet River/Indiana Harbor Canal (fig. 5 and 

table 14). The maximum instantaneous load of total mercury in 

surface water (in 2001 or 2002, table 12) for the sampling locations in six of the eight reaches was compared with the estimated maximum load of mercury in ground-water discharge. In 

these six reaches, the mercury load in surface water was 2.4 to 

20.9 percent ground-water discharge. The largest contributions 

of mercury from ground water were at site M14 (20.9 percent) 

and site M16 (20 percent) in the East Branch Grand Calumet 

River and site M12 (11.9 percent) in the West Branch Grand 

Calumet River. Sites M14 and M12 are near wetlands, and site 

M16 is downstream from wetlands.

Table 14. Maximum estimated loads of total mercury in ground-water discharges to stream reaches and maximum instantaneous 

loads of total mercury at eight sampling locations on the Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, 

August 2001 and May 2002.

[ID, identification; mg/hr, milligram per hour; GCR, Grand Calumet River]

Sampling location and ID Stream reacha

a

Stream reaches are identified on figure 5.

b

Maximum estimated loads from Willoughby and Siddeeq (2001, p. 35) were in kilograms per day and were converted to an equivalent milligrams 

per hour for table 14.

Estimated 

ground-water load: 

maximum load 

of total mercury 

in 

ground-water discharge 

(mg/hr)b

Estimated 

surface-water load: 

maximum instantaneous 

load of total mercury 

in 

surface water 

(mg/hr)

Ratio of 

ground-water load 

to 

surface-water load 

(percent)

M16 East Branch GCR B 50.0 250 20.0

M14 East Branch GCR C 83.3 399 20.9

M13 East Branch GCR C 8.3 304 2.7

M12 West Branch GCR E 8.3 70 11.9

M9 West Branch GCR D 8.3 89 9.4

M7 Indiana Harbor Canal F 16.7 703 2.4

M4 Indiana Harbor Canal H 16.7 542 3.1

M2 Indiana Harbor Canal H 16.7 349 4.8
26 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Inputs of Mercury

Data are needed to determine the proportional inputs 

of mercury to the Grand Calumet River/Indiana Harbor Canal 

that contribute to a TMDL. Some of these data were provided 

through this study; other data sources are identified in this 

discussion.

• Treated Effluent. Mercury concentrations from 

municipal and industrial outfalls were obtained during 

this study; discharge volumes can be estimated from 

municipal and industrial records.

• Ground Water. Estimated mercury loading from 

ground-water discharge to eight reaches of the Grand 

Calumet River/Indiana Harbor Canal (Willoughby and 

Siddeeq, 2001) were based on mercury concentrations 

determined in ground-water samples in the study area 

(Duwelius and others, 1996).

• Atmospheric Deposition. Seasonal and annual total 

mercury wet-deposition data from the NADP Mercury 

Deposition Network station at the Indiana Dunes 

National Lakeshore can be used to estimate atmospheric deposition to the Grand Calumet River Basin.

• Noncontact Industrial Effluent. Mercury concentrations from Lake Michigan near or in the water-supply 

intakes may represent mercury in noncontact industrial 

effluent. These data were obtained during this study 

and compared with historical data.

• Stormwater Runoff. This input of mercury potentially could be inferred from atmospheric deposition 

and a runoff coefficient or with data on flow and mercury concentrations in samples from storm sewers and 

combined-sewer overflows during storms.

• Contaminated Sediment. This input of mercury 

could be estimated with concentrations in sediment. 

Releases from contaminated sediment potentially could 

be inferred by mass balance with data on the total mercury load and the proportional input from the other 

sources.

SummaryandConclusions

The Grand Calumet River/Indiana Harbor Canal was first 

on the IDEM list of water bodies scheduled for development of 

a TMDL for mercury under provisions of the Clean Water Act 

section 303(d). A TMDL, if developed, could be used by IDEM 

to limit mercury discharges from permitted point sources in an 

effort to achieve the Indiana water-quality standard of 1.3 ng/L 

total mercury for waters within the Great Lakes system. The 

mercury TMDL required a base line of data with mercury 

reporting limits less than 1.3 ng/L, but few reliable data were 

available. IDEM requested that the USGS obtain data on the 

occurrence and distribution of mercury in the Grand Calumet 

River/Indiana Harbor Canal and near-shore Lake Michigan 

with ultra-clean sampling protocols and low-level analytical 

methods. 

The USGS collected samples during warm, dry weather 

in summer 2001 and cool, wet weather in spring 2002 that 

provided a contrast in streamflow conditions and seasonal 

extremes of historical suspended-sediment concentrations. 

Total mercury and methylmercury were analyzed in water samples. Sets of filtered and particulate samples were collected to 

estimate mercury partitioning between water and particulates. 

To evaluate the types of particulates potentially transporting 

mercury, supplementary constituents were analyzed to estimate 

the size, organic-carbon content, and plant-pigment content of 

particulates in the water. Comparability of the mercury data was 

promoted by: (1) sample collection during short-duration time 

periods; (2) streamflow measurements for comparison of 

hydrologic conditions; (3) use of the same field equipment, supplies, sampling procedures, personnel, and analytical laboratory 

for all samples.

Total mercury concentrations in all the Grand Calumet 

River/Indiana Harbor Canal samples exceeded the Indiana 

water-quality standard. Most total mercury concentrations in 

the Grand Calumet River/Indiana Harbor Canal were larger 

than those in Lake Michigan. Total mercury and methylmercury 

concentrations were larger in more samples collected during 

the wet-weather streamflow conditions during May 2002 

than in samples collected during the dry-weather streamflow 

conditions during August 2001. The largest total mercury concentrations were in the West Branch Grand Calumet River near 

wetlands and municipal outfalls (17.2 ng/L) and in the Indiana 

Harbor Canal near the confluence of the East Branch and West 

Branch Grand Calumet River (16.0 ng/L). 

Methylmercury was no more than 1.5 percent of the total 

mercury concentration in August 2001 and no more than 

6.2 percent in May 2002. Methylmercury concentrations were 

correlated with concentrations of dissolved solids, total organic 

carbon, and sulfate. 

Particulate total mercury was the predominant form of 

total mercury detected in the Grand Calumet River/Indiana 

Harbor Canal, and nearly all methylmercury detected was particulate. The estimated composition of most of the particulates 

in the water samples from the Grand Calumet River/Indiana 

Harbor Canal was sediment larger than medium clay containing 

less than 2 percent particulate organic carbon and less than 

0.08 percent plant pigment. 

Estimated instantaneous total mercury loads in the Indiana 

Harbor Canal were as large as 703 mg/hr in August 2001 and 

542 mg/hr in May 2002. As much as 21 percent of the instantaneous mercury load in some stream reaches could have been 

from ground-water discharge. Municipal effluent had larger and 
Acknowledgments 27

more variable mercury concentrations than industrial effluent 

and presents a potential for larger mercury loads, based on concentration. 

This study adds to a base line of data about mercury in the 

Grand Calumet River/Indiana Harbor Canal. Comparisons of 

data from this study with historical data indicate that substantial 

changes in mercury concentrations and mercury transport in the 

study area probably have not occurred from 1994 through 2002. 

Data are needed to determine the proportional inputs of mercury 

to the Grand Calumet River/Indiana Harbor Canal from all the 

sources that contribute to a TMDL. 

Acknowledgments

The author acknowledges Mark Olson and Shane Olund 

of the USGS Mercury Research Laboratory, who provided considerable technical support and advice. Appreciation also is 

extended to Kathy Luther, formerly of the Indiana Department 

of Environmental Management Northwest Indiana Office, who 

was key to development of the study and coordination with 

industries, municipalities, and citizens in northwestern Indiana.
28 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

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no. 3, p. 942–947.
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Atmospheric Deposition Program 1999 Wet Deposition: 

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Committee on the Toxicological Effects of Methylmercury, 

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Appendixes 1–3.
32 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 1–1. Total mercury and methylmercury concentrations, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, August 2001. [ID, identification; ng/L, nanogram per liter; < , less than reporting limit listed; GCR, Grand Calumet River; IHC, Indiana Harbor Canal]

aDetection limit for particulate total mercury was 0.03 nanogram per liter for all samples.

bCombined total mercury and combined methylmercury computed as sum of dissolved and particulate concentrations except for footnote “f” belo

w.

cDetection limit for dissolved and particulate methylmercury was 0.001 nanogram per liter for all samples.

dEstimated concentration; more than 5 times and less than 10 times the mean concentration in five field blanks (table 1–5).

eConcentration in one of two sequentially collected field duplicate samples.

fConcentration was less than five times the mean concentration in five field blanks (table 1–5). Not used to compute combined total mercury concentration.

Dissolved total mercury Combined 

 methylmercury to 

combined 

total 

mercury 

 (percent)

Particulate 

 total 

mercury to 

combined

 total 

 mercury 

 (percent)

Sampling-location ID and name

Sample 

concentration 

(ng/L)

Detection 

limit 

(ng/L)

Particulate 

total 

mercurya 

(ng/L)

Combinedb

total 

mercury 

(ng/L)

Dissolvedc 

methylmercury 

(ng/L)

Particulatec 

methylmercury 

(ng/L)

Combinedb

 methylmercury 

(ng/L)

M19 Grand Calumet Lagoons, west 2.34d 0.004 0.83 3.17 <0.001 0.030 0.030 0.9 26.2

M18 East Branch GCR headwaters .53e, f .008 2.56e 2.56 <.001e .013e .013 .5 100

M16 East Branch GCR at Bridge St. .69f .004 5.25 5.25 <.001 .013 .013 .2 100

M14 East Branch GCR at Cline Ave. .65f .025 2.72 2.72 <.001 .008 .008 .3 100

M13 East Branch GCR at Kennedy Ave. .58e, f .025 3.96e 3.96 <.001e .012e .008 .3 100

M12 West Branch GCR at Hohman Ave. .59f .004 6.30 6.30 .045 .046 .091 1.4 100

M9 West Branch GCR at Indianapolis Blvd. 1.78e .008 14.1e 15.9 <.001e .057e .050 .4 88.8

M7 IHC at Columbus Dr. .42f .008 16.0 16.0 <.001 .015 .015 .1 100

M6 IHC at Lake George Canal .80f .008 3.42 3.42 <.001 .012 .012 .4 100

M4 IHC at Dickey Rd. 1.26e .004 7.56e 7.56 <.001e .024e .015 .3 100

M2 IHC at mouth of Indiana Harbor .51f .025 2.28 2.28 <.001 .010 .010 .4 100

IH1 Indiana Harbor near industrial intake .47e, f .008 .18 .18 <.001e .001e .001 .6 100

LM1 Lake Michigan near industrial intake 1 .52f .004 .26 .26 <.001 .004 .004 1.5 100

LM2 Lake Michigan near industrial intake 2 .45f .004 .34 .34 <.001e .004e .004 1.2 100
Estimated Loads of Combined Total Mercury 33

Table 1–2. Estimated loads of combined total mercury during the time of sampling at eight sampling locations, Grand Calumet River/ 

Indiana Harbor Canal, Lake County, Indiana, August 2001.

[ID, identification; hour start and end in military time; ft3/s, cubic foot per second; total mercury concentration is a sum of dissolved and particulate total mercury 

concentrations; ng/L, nanogram per liter; mg/hr, milligram per hour; ADCP, acoustic Doppler current profiler]

aCombined total mercury computed as sum of dissolved total mercury and particulate total mercury concentrations (table 1–1).

bCombined total mercury load calculated as product of streamflo

w, total mercury concentration, and a conversion factor (0.101941). Calculations made with 

unrounded values and presented with three significant digits for the hour of sample collection. 

cStreamflow calculated for time of sampling as mean of discharge measured during 4 to 14 stream transects with tethered acoustic Doppler current profiler.

dConcentration in one of two sequential duplicate samples.

eU.S. Geological Survey streamflow-gaging station 05536357 on West Branch Grand Calumet River at Hohman Ave. Streamflow calculated for hour of 

sampling from single value for stream stage with stage-discharge method.

fU.S. Geological Survey streamflow-gaging station 04092750 on Indiana Harbor Canal at former Canal St. bridge site—upstream from Dickey Rd. (M4) 

and downstream from confluence with Lake George Canal. Gage used acoustic Doppler velocity meter; streamflow computed with index-velocity method. 

Streamflow calculated for hour of sampling as mean of four quarter-hour instantaneous streamflow values.

Sampling-location ID and name

Date 

for 

mercury-

 load 

estimate

Hour 

for 

mercury-

 load 

estimate

Streamflow 

(ft3/s)

Source of 

streamflow 

data

Combined 

total mercury 

concentrationa

(ng/L)

Loadb of 

combined 

total 

mercury 

(mg/hr)

East Branch Grand Calumet River

M16 (at Bridge St.) 8/21/01 1500–1600 467 Tethered ADCPc 5.25 250

M14 (at Cline Ave.) 8/22/01 1130–1230 529 Tethered ADCPc 2.72 147

M13 (at Kennedy Ave.) 8/22/01 1700–1800 691 Tethered ADCPc 3.96d 279

West Branch Grand Calumet River

M12 (at Hohman Ave.) 8/23/01 1530–1530 7.9 Streamflow-gaging statione 6.30 5.07

M9 (at Indianapolis Blvd.) 8/23/01 1100–1200 44.6 Current meter 15.9d 72.2

Indiana Harbor Canal

M7 (at Columbus Dr.) 8/20/01 1800–1900 431 Streamflow-gaging stationf 16.0 703

M4 (at Dickey Rd.) 8/28/01 1230–1330 551 Streamflow-gaging stationf 7.56d 425

M2 (at mouth of Indiana Harbor) 8/29/01 1130–1230 578 Streamflow-gaging stationf 2.28 134
34 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 1–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, August 2001. [ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; n.a., not analyzed; GCR, Grand Calumet River; IHC, Indiana Harbor Canal; μg/L, microgram per liter; CaCO3, calcium carbonate; SiO2, silicon dioxide; < , less than reporting limit listed; E, estimated concentration] Sampling-location ID and name pH (s.u.) Dissolved oxygen (mg/L) Water temperature 

(°C)

Specific 

conductance 

(μS/cm)

Turbidity 

(ntu)

Suspended 

sedimenta

(mg/L)

Seston 

ash-free 

dry massb

(mg/L)

Suspended 

sediment 

to seston 

ratioc 

(percent)

M19 Grand Calumet Lagoons, west 8.4 13.0 23.5 560 17.3 14.7 n.a. n.a.

M18 East Branch GCR headwaters 7.3 4.7 20.0 1,100 19.3 8.5 13.4 63

M16 East Branch GCR at Bridge St. 8.2 7.6 29.0 368 13.9 13.2 10.6 100

M14 East Branch GCR at Cline Ave. 7.9 6.3 28.5 409 3.8 7.1 n.a. n.a.

M13 East Branch GCR at Kennedy Ave. 8.0 6.5 29.5 407 3.6 9.4 9.3 100

M12 West Branch GCR at Hohman Ave. 7.4 6.5 26.0 1,300 2.5 4.7 12.0 39

M9 West Branch GCR at Indianapolis Blvd. 7.1 6.1 24.0 1,250 3.8 45.3 11.3 100

M7 IHC at Columbus Dr. 7.9 6.6 29.0 474 n.a. 10.9 10.6 100

M6 IHC at Lake George Canal 7.7 5.4 28.0 494 5.0 3.2 n.a. n.a.

M4 IHC at Dickey Rd. 7.6 4.4 28.0 495 7.3 6.2 n.a. n.a.

M2 IHC at mouth of Indiana Harbor 8.0 6.6 26.0 369 6.9 5.8 n.a. n.a.

IH1 Indiana Harbor near industrial intake 8.1 6.6 28.5 362 1.1 1.4 n.a. n.a.

LM1 Lake Michigan near industrial intake 1 8.2 7.0 22.5 316 1.9 1.1 n.a. n.a.

LM2 Lake Michigan near industrial intake 2 8.2 7.8 22.5 295 2.2 3.6 n.a. n.a.
Water-Quality Characteristics, Physical Properties, and Major Ions 35

Table 1–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, 

August 2001.—Continued

[ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; n.a., not analyzed; 

GCR, Grand Calumet River; IHC, Indiana Harbor Canal; μg/L, microgram per liter; CaCO3, calcium carbonate; SiO2, silicon dioxide; < , less than reporting limit listed; E, estimated concentration]

Samplinglocation 

ID

Dissolved 

solids 

(mg/L)

Dissolved

organic 

carbon 

(mg/L)

Total 

organic 

carbon 

(mg/L)

Particulate 

organic 

carbond 

(mg/L)

Particulate 

carbon 

to seston 

ratioe 

(percent)

Chlorophyll-a 

(μg/L)

Pheophytin-a 

(μg/L)

Plant 

pigment 

to seston 

 ratiof 

(percent)

Dissolved 

calcium 

(mg/L)

Dissolved

magnesium 

(mg/L)

Dissolved 

sodium 

(mg/L)

M19 342 10.3 10.6 0.30 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

M18 558 8.45 8.54 .09 .67 6.06 2.88 .07 95.7 26.8 35.7

M16 216 2.52 2.56 .04 .38 2.11 1.41 .03 38.9 15.2 10.1

M14 224 2.78 2.61 0 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

M13 232 3.19 2.96 0 0 .82 .60 .02 41.6 14.7 15.0

M12 818 8.44 8.26 0 0 33.4 5.91 .33 65.9 60.4 101

M9 778 7.24 7.28 .04 .35 1.72 1.30 .03 67.4 51.8 96.6

M7 287 3.56 3.10 0 0 .92 1.22 .02 43.9 16.6 20.6

M6 286 2.92 3.01 .09 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

M4 292 2.79 2.78 0 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

M2 194 2.28 2.20 0 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

IH1 202 2.44 2.52 .08 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

LM1 170 1.94 2.02 .08 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

LM2 166 1.90 1.92 .02 n.a. n.a. n.a. n.a. n.a. n.a. n.a.
36 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 1–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, August 2001.—Continued [ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; n.a., not analyzed; GCR, Grand Calumet River; IHC, Indiana Harbor Canal; μg/L, microgram per liter; CaCO3, calcium carbonate; SiO2, silicon dioxide; < , less than reporting limit listed; E, estimated concentration]

aSuspended sediment includes solids retained on a 1.5-micrometer filter.

bSeston includes suspended sediment and suspended fine particulates retained on a 0.7-micrometer filter.

cRatio computed as suspended sediment divided by seston, expressed as percent; value larger than 100 percent displayed as 100.

d

Particulate organic carbon computed as total organic carbon minus dissolved organic carbon; negative difference displayed as zero.

eRatio computed as particulate organic carbon divided by seston, expressed as percent; zero ratio indicates zero particulate organic carbon.

fRatio computed as sum of chlorophyll-a and pheophytin-a divided by seston ash-free dry mass, expressed as percent.

Table 1–4. Unfiltered total mercury and water-quality characteristics of effluent samples, Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, August 2001.

[ID, identification; ng/L, nanogram per liter; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; GCR, Grand Calumet River; IHC, Indiana Harbor Canal]

aConcentration in one of two sequential duplicate samples.

Samplinglocation 

ID

Dissolved 

potassium 

(mg/L)

Dissolved 

iron 

(μg/L)

Dissolved 

manganese 

(μg/L)

Dissolved 

alkalinity 

as CaCO3

(mg/L)

Dissolved 

chloride 

(mg/L)

Dissolved 

sulfate 

(mg/L)

Dissolved 

fluoride 

(mg/L)

Dissolved 

silica 

as SiO2

(mg/L)

Dissolved 

orthophosphate 

(mg/L)

M18 6.1 117 434 273 76.9 169 0.87 20 <0.02

M16 2.7 <10 7 108 27.2 28.7 .47 1.2 <.02

M13 4.0 13 11 107 35.6 40.4 .45 1.7 .01E

M12 11.1 93 19 139 148 248 .98 4.9 .64E

M9 11.1 77 6 134 152 209 .99 7.5 1.0 E

M7 5.1 18 12 111 45.4 54.3 .52 2.2 .05E

Sampling-location ID and name Unfiltered total mercury (ng/L) pH (s.u.) Dissolved oxygen (mg/L) Water temperature 

(°C)

Specific conductance 

(μS/cm)

MO1 West Branch GCR municipal outfall 1 0.60 7.1 7.1 24.0 1,220

MO2 West Branch GCR municipal outfall 2 10.8a 7.3 7.9 23.5 1,180

IO1 IHC industrial outfall 2.00a 8.2 3.0 35.0 562
Total Mercury in Field-Blank Samples 37

Table 1–5. Total mercury in field-blank samples, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, 

Indiana, August 2001.

[ID, identification; ng/L, nanogram per liter; dissolved methylmercury was analyzed but not detected in any sample; -- , does not apply]

aBlank correction is sum of mercury in blank water (0.1 nanogram per liter) and mercury added from acid preservative (0.06 nanogram per liter). 

The U.S. Geological Survey Mercury Research Laboratory’s long-term total mercury concentration in the blank water was 0.1 nanogram per liter. 

Maximum concentration of mercury added to blank water from acid preservative (0.06 nanogram per liter) was based on 1.55-nanogram-per-liter 

mercury remaining in preservative after field use, diluted at 20-milliliter acid per 500-milliliter sample.

Sample ID 

Dissolved 

total 

mercury 

(ng/L)

Blankcorrected 

dissolved 

total 

mercury 

(ng/L)

Explanation

FB1 0.43 0.27 Blank-corrected concentration of mercury in filtered, pumped field blank was 

computed by subtracting 0.16 ng/La

.

FB2 .65 .49 Same as above.

FB3 .26 .10 Same as above.

FB4 .22 .06 Same as above.

FB5 .61 .45 Same as above.

Mean -- .27 Mean blank-corrected dissolved total mercury concentration in five field blanks.
38 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 1–6. Variability of selected constituents in sequential duplicate samples, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, August 2001. [ID, identification; ng/L, nanogram per liter; RPD, relative percent difference; n.a., not analyzed; mg/L, milligram per liter]

aDifference between concentration of first sample and concentration of second sample.

bRelative percent difference is the difference of the two concentrations divided by the average of the concentrations, expressed as percent (for comparative purposes).

Samplinglocation

ID

Dissolved total mercury 

(ng/L) Samplinglocation

ID

Particulate total mercury 

(ng/L) Samplinglocation

ID

Particulate methylmercury 

(ng/L)

First

sample

Second

sample

Differencea RPDb First sample Second sample Differ- encea RPDb First sample Second sample Differ- encea RPDb

M18 0.46 0.53 0.07 14.1 M18 2.56 0.32 2.24 155.6 M18 0.013 0.013 0 0

M13 .49 .58 .09 16.8 M13 3.96 3.63 .33 8.70 M13 .008 .012 .004 40

M9 .85 1.78 .93 70.7 M9 9.79 14.1 4.27 35.8 M9 .050 .057 .007 13.1

M4 1.26 .57 .69 75.4 M4 5.80 7.55 1.75 26.2 M4 .015 .024 .009 46.2

IH1 .30 .47 .17 44.2 IH1 .17 .18 .01 5.70 IH1 .001 .001 0 0

LM2 n.a. n.a. n.a. n.a. LM2 .30 .34 .04 12.5 LM2 .004 .004 0 0

Samplinglocation

ID

Unfiltered total mercury 

(ng/L) Samplinglocation

ID

Suspended sediment 

(mg/L) Samplinglocation

ID

Total organic carbon 

(mg/L)

First

sample

Second

sample

Differencea RPDb First sample Second sample Differ- encea RPDb First sample Second sample Differ- encea RPDb

MO2 2.65 10.79 8.14 121.1 M13 9.4 5.7 3.7 49.0 M13 3.0 3.1 0.1 3.3

IO1 2.00 1.52 .48 27.3 LM2 3.6 4.0 .4 10.5 LM2 1.9 2.0 .1 5.1
Total Mercury and Methylmercury Concentrations 39

Table 2–1. Total mercury and methylmercury concentrations, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, May 2002.

[ID, identification; ng/L, nanogram per liter; < , less than reporting limit listed; GCR, Grand Calumet River; n.a., not analyzed; IHC, Indiana Harbor Canal]

aDetection limit for particulate total mercury was 0.03 nanogram per liter for all samples.

bCombined total mercury and combined methylmercury computed as sum of dissolved and particulate concentrations. 

cDetection limit for dissolved methylmercury was 0.002 nanogram per liter for all samples.

dDetection limit for particulate methylmercury was 0.001 nanogram per liter for all samples.

eUnfiltered sample—detection limit was 0.002 nanogram per liter for unfiltered methylmercury.

fConcentration in one of two sequentially collected duplicate samples.

Dissolved total mercury Combined 

 methylmercury 

to 

combined 

 total 

mercury 

(percent)

Particulate 

total 

mercury 

to 

 combined 

total 

mercury 

(percent)

Sampling-location ID and name

Sample 

concentration

(ng/L)

Detection 

limit 

(ng/L)

Particulatea 

total 

mercury 

(ng/L)

Combinedb 

total 

mercury 

(ng/L)

Dissolvedc

methylmercury 

(ng/L)

Particulated

methylmercury 

(ng/L)

Combinedb

 methylmercury 

(ng/L)

M19 Grand Calumet Lagoons, west 0.62 0.006 2.59 3.21 <0.002 0.046 0.046 1.4 80.6

M18 East Branch GCR headwaters .64 .005 1.25 1.89 .069 .048 .117f 6.2 66.2

M16 East Branch GCR at Bridge St. .26 .005 1.37 1.63 n.a. n.a. <.002e 0 83.9

M14 East Branch GCR at Cline Ave. .37 .005 6.88 7.25 n.a. n.a. <.002e 0 94.8

M13 East Branch GCR at Kennedy Ave. .42 .005 4.32 4.74 n.a. n.a. <.002e 0 91.1

M12 West Branch GCR at Hohman Ave. 1.76 .005 15.4 17.2 n.a. n.a. .181 1.1 89.8

M9 West Branch GCR at Indianapolis Blvd. 1.28 .006 4.20 5.48 <.002 .147 .147f 2.7 76.6

M7 IHC at Columbus Dr. .81 .005 4.95 5.76 <.002 .068 .068f 1.2 86.0

M6 IHC at Lake George Canal .95 .004 5.92 6.87 n.a. n.a. .042e .6 86.2

M4 IHC at Dickey Rd. .76 .004 5.62 6.38 n.a. n.a. .046e .7 88.0

M2 IHC at mouth of Indiana Harbor .50 .003 3.88 4.38 n.a. n.a. <.002e 0 88.6

IH1 Indiana Harbor near industrial intake .43 .004 2.63 3.06 n.a. n.a. <.002e, f 0 85.9

LM1 Lake Michigan near industrial intake 1 .45 .004 1.65 2.10 n.a. n.a. <.002e 0 78.6

LM2 Lake Michigan near industrial intake 2 .69 .004 .62 1.31 <.002 .004 .004 .3 47.3
40 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 2–2. Estimated loads of combined total mercury during the time of sampling at eight sampling locations, Grand Calumet River/ Indiana Harbor Canal, Lake County, Indiana, May 2002. [ID, identification; hour start and end in military time; ft3/s, cubic foot per second; ng/L, nanogram per liter; mg/hr, milligram per hour; ADCP, acoustic Doppler current profiler]

a

Total mercury concentration is a sum of dissolved and particulate total mercury concentrations.

bMercury load calculated as product of streamflo

w, total mercury concentration, and a conversion factor (0.101941). Calculations made with unrounded values 

and presented with three significant digits for the hour of sample collection. 

cStreamflow calculated for time of sampling as mean of discharge measured during 4 to 14 stream transects with tethered acoustic Doppler current profiler.

dU.S. Geological Survey streamflow-gaging station 05536357 on West Branch Grand Calumet River at Hohman Ave. Streamflow calculated for hour of sampling 

from single value for stream stage with stage-discharge method.

eU.S. Geological Survey streamflow-gaging station 04092750 on Indiana Harbor Canal at former Canal St. bridge site—upstream from Dickey Rd. (M4) and 

downstream from confluence with Lake George Canal. Gage used acoustic Doppler velocity meter; streamflow computed with index-velocity method. Streamflow 

calculated for hour of sampling as mean of four quarter-hour instantaneous streamflow values.

Sampling-location ID and name

Date 

for 

mercury-

 load 

estimate

Hour 

for 

mercury-

 load 

estimate

Streamflow 

(ft3/s)

Source 

of 

streamflow 

data

Combined 

total 

mercury 

concentrationa

(ng/L)

Loadb of 

combined 

total 

mercury 

(mg/hr)

East Branch Grand Calumet River

M16 (at Bridge St.) 5/07/02 1500–1600 446 Tethered ADCPc 1.63 74.1

M14 (at Cline Ave.) 5/08/02 0930–1030 540 Current meter 7.25 399

M13 (at Kennedy Ave.) 5/08/02 1430–1530 629 Tethered ADCPc 4.74 304

West Branch Grand Calumet River

M12 (at Hohman Ave.) 5/09/02 1200–1300 40 Streamflow-gaging stationd 17.2 70.0

M9 (at Indianapolis Blvd.) 5/09/02 1000–1100 159 Current meter 5.48 88.8

Indiana Harbor Canal

M7 (at Columbus Dr.) 5/06/02 1630–1730 580 Streamflow-gaging statione 5.76 341

M4 (at Dickey Rd.) 5/15/02 1500–1600 834 Streamflow-gaging statione 6.38 542

M2 (at mouth of Indiana Harbor) 5/15/02 1700–1800 782 Streamflow-gaging statione 4.38 349
Water-Quality Characteristics, Physical Properties, and Major Ions 41

Table 2–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, 

Indiana, May 2002.

[ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; GCR, Grand Calumet River; 

IHC, Indiana Harbor Canal; μg/L, microgram per liter; n.a., not analyzed; CaCO3, calcium carbonate; SiO2, silicon dioxide; < , less than reporting limit listed; E, estimated concentration]

Sampling-location ID and name pH (s.u.) Dissolved oxygen (mg/L) Water temper- nature 

(°C)

Specific 

conductdance 

(μS/cm)

Turbidity 

(ntu)

Suspended 

sedimenta

(mg/L)

Seston 

ash-free 

dry massb

(mg/L)

Suspended 

sediment 

to seston 

ratioc 

(percent)

M19 Grand Calumet Lagoons, west 7.9 8.3 16.5 639 12.0 16.8 16 100

M18 East Branch GCR headwaters 7.3 5.2 14.5 851 16.2 21.6 3.3 100

M16 East Branch GCR at Bridge St. 8.1 9.6 17.5 356 .3 7.2 8.3 87

M14 East Branch GCR at Cline Ave. 7.7 7.9 17.0 442 21.6 13.6 8.6 100

M13 East Branch GCR at Kennedy Ave. 7.6 7.4 17.0 491 11.7 32.1 10 100

M12 West Branch GCR at Hohman Ave. 7.2 1.5 16.5 500 15.3 13.7 10 100

M9 West Branch GCR at Indianapolis Blvd. 7.2 6.2 15.5 813 8.9 12.4 13 95

M7 IHC at Columbus Dr. 7.3 6.7 18.0 597 8.8 15.1 10 100

M6 IHC at Lake George Canal 7.3 6.4 17.5 686 7.0 5.3 7.6 70

M4 IHC at Dickey Rd. 7.3 5.3 17.5 683 8.0 32.2 7.6 100

M2 IHC at mouth of Indiana Harbor 7.7 8.8 12.5 378 6.5 4.8 7.4 65

IH1 Indiana Harbor near industrial intake 7.8 6.8 15.5 386 4.0 2.0 6.7 30

LM1 Lake Michigan near industrial intake 1 8.2 8.6 11.5 330 3.6 1.1 6.3 17

LM2 Lake Michigan near industrial intake 2 8.0 9.8 11.0 270 4.9 4.4 5.6 79
42 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 2–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, May 2002.—Continued [ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; GCR, Grand Calumet River; HC, Indiana Harbor Canal; μg/L, microgram per liter; n.a., not analyzed; CaCO3, calcium carbonate; SiO2, silicon dioxide; < , less than reporting limit listed; E, estimated concentration] Sampling- location ID Dissolved solids (mg/L) Dissolved organic carbon (mg/L) Total organic carbon (mg/L) Particulate organic carbond (mg/L) Particulate carbon to seston ratioe (percent) Chlorophyll-a 

(μg/L)

Pheophytin-a 

(μg/L)

Plant 

pigment 

to seston 

 ratiof

(percent)

Dissolved 

calcium 

(mg/L)

Dissolved 

magnesium

(mg/L)

Dissolved 

sodium

(mg/L)

M19 400 6.48 6.65 0.17 1.1 14.96 8.97 0.15 71.9 24.7 22.8

M18 504 6.75 6.81 .06 1.8 5.00 4.42 .29 86.2 25.2 29.3

M16 206 2.05 2.12 .07 .8 1.35 1.27 .03 35.3 15.3 11.3

M14 253 2.92 3.03 .11 1.3 2.19 1.92 .05 n.a. n.a. n.a.

M13 286 3.19 3.27 .08 .8 1.70 1.96 .04 43.7 15.9 26.6

M12 304 6.83 6.85 .02 .2 4.61 3.08 .08 n.a. n.a. n.a.

M9 492 6.32 6.47 .15 1.2 6.49 4.48 .08 54.7 17.1 76.4

M7 359 4.07 4.22 .15 1.5 2.70 2.88 .06 49.2 17.0 42.3

M6 412 5.30 5.24 0 0 4.34 2.35 .09 n.a. n.a. n.a.

M4 406 4.64 4.83 .19 2.5 2.33 1.54 .05 n.a. n.a. n.a.

M2 254 2.24 3.32 1.08 14.6 1.84 1.19 .04 42.3 14.1 22.1

IH1 221 3.23 3.25 .02 .3 1.04 .59 .02 n.a. n.a. n.a.

LM1 203 1.93 1.94 .01 .2 1.34 .76 .03 n.a. n.a. n.a.

LM2 172 1.88 6.49 4.61 82.3 1.47 1.37 .05 n.a. n.a. n.a.
Water-Quality Characteristics, Physical Properties, and Major Ions 43

Table 2–3. Water-quality characteristics, physical properties, and major ions, Grand Calumet River/Indiana Harbor Canal and 

Lake Michigan, Lake County, Indiana, May 2002.—Continued

[ID, identification; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; ntu, nephelometric turbidity unit; 

GCR, Grand Calumet River; IHC, Indiana Harbor Canal; μg/L, microgram per liter; n.a., not analyzed; CaCO3, calcium carbonate; SiO2, silicon dioxide; 

< , less than reporting limit listed; E, estimated concentration]

aSuspended sediment includes solids retained on a 1.5-micrometer filter.

bSeston includes suspended sediment and suspended fine particulates retained on a 0.7-micrometer filter.

cRatio computed as suspended sediment divided by seston, expressed as percent; value larger than 100 percent displayed as 100.

d

Particulate organic carbon computed as total organic carbon minus dissolved organic carbon; negative difference displayed as zero.

eRatio computed as particulate organic carbon divided by seston, expressed as percent; zero ratio indicates zero particulate organic carbon.

fRatio computed as sum of chlorophyll-a and pheophytin-a divided by seston, expressed as percent.

Table 2–4. Unfiltered total mercury and water-quality characteristics of effluent samples, Grand Calumet River/Indiana Harbor Canal, Lake County, Indiana, May 2002.

[ID, identification; ng/L, nanogram per liter; s.u., standard unit; mg/L, milligram per liter; °C, degree Celsius; μS/cm, microsiemen per centimeter; GCR, Grand Calumet River; IHC, Indiana Harbor Canal]

aConcentration in one of two sequential duplicate samples.

Samplinglocation 

ID

Dissolved 

potassium 

(mg/L)

Dissolved 

iron 

(μg/L)

Dissolved 

manganese

(μg/L)

Dissolved 

alkalinity 

as CaCO3

(mg/L)

Dissolved 

chloride 

(mg/L)

Dissolved 

sulfate 

(mg/L)

Dissolved 

fluoride 

(mg/L)

Dissolved 

silica 

as SiO2 

(mg/L)

Dissolved 

orthophosphate 

(mg/L)

M19 5.0 220 74.3 198 49.9 73.2 0.61 1.2 <0.02

M18 5.2 303 291 241 59.4 125 .80 9.5 <.02

M16 2.5 7.6 8.4 110 23.7 29.8 .57 1.6 .02

M13 4.0 22.6 23.4 113 46.5 48.1 .57 2.9 .01E

M9 6.2 57.5 15.5 126 101 96.3 .57 6.6 .34

M7 4.9 19.0 26.7 130 66.5 63.0 .56 4.0 .06

M2 3.2 8.9 17.3 160 34.6 42.8 .33 2.9 .01E

Sampling-location ID and name Unfiltered total mercury (ng/L) pH (s.u.) Dissolved oxygen (mg/L) Water temperature 

(°C)

Specific 

conductance 

(μS/cm)

MO1 West Branch GCR municipal outfall 1 1.08a 7.1 9.0 16.0 678

MO2 West Branch GCR municipal outfall 2 2.48 7.2 8.2 15.5 792

IO1 IHC industrial outfall 3.71 7.7 6.6 23.5 678
44 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan Table 2–5. Total mercury in field-blank samples, Grand Calumet River/Indiana Harbor Canal and Lake Michigan, Lake County, Indiana, May 2002. [ID, identification; ng/L, nanogram per liter; n.a., not analyzed; -- , does not apply; < , less than reporting limit listed]

aMaximum concentration added to blank water (0.01 nanogram per liter) was based on 0.3010-per-liter mercury remaining in acid preservative after field use, diluted at 20-milliliter acid per 

500-milliliter sample.

Sample 

ID 

Unfiltered 

total 

mercury 

(ng/L)

Particulate 

total 

mercury 

(ng/L)

Total 

mercury 

in 

blank water 

(ng/L)

Blankcorrected 

total 

mercury 

 (ng/L)

Explanation

BW1 0.09 n.a. 0.08 -- Concentration of mercury in blank water poured from field container into sample bottle was 

computed by subtracting mercury from preservative (0.01 ng/L)a

.

BW2 .05 n.a. .04 -- Same as above.

BW3 .13 n.a. .12 -- Same as above.

BW4 .13 n.a. .12 -- Same as above.

Mean -- -- .09 -- Mean concentration of mercury in blank water computed from four samples.

EB1 .06 n.a. -- 0 Blank-corrected concentration of mercury in unfiltered, pumped field blank was computed by 

subtracting mean concentration in blank water (0.09 ng/L).

EB2 .07 n.a. -- 0 Same as above.

EB3 .15 n.a. --. .06 Same as above.

EB4 .11 n.a. -- .02 Same as above.

Mean -- -- -- .02 Mean blank-corrected concentration of mercury in four field blanks.

FB1 n.a. <.03 -- 0 Blank-corrected concentration of mercury on filter was computed by subtracting mean concentration 

in blank water (0.09 ng/L).

FB2 n.a. .12 -- .03 Same as above.

Mean -- -- -- .01 Mean blank-corrected concentration of mercury in two field blanks.
Variability of Selected Constituents in Sequential Duplicate Samples 45

Table 2–6. Variability of selected constituents in sequential duplicate samples, Grand Calumet River/Indiana Harbor Canal 

and Lake Michigan, Lake County, Indiana, May 2002.

[ID, identification; ng/L, nanogram per liter; RPD, relative percent difference]

a

Difference between concentration of first sample and concentration of second sample.

b

Relative percent difference is the difference of the two concentrations divided by the average of the concentrations, expressed as percent 

(for comparative purposes).

Unfiltered total mercury 

(ng/L)

Unfiltered methylmercury 

(ng/L)

Samplinglocation 

ID

First 

sample

Second 

sample Differencea RPDb First 

sample

Second 

sample Differencea RPDb

M18 2.50 2.52 0.02 0.8 0.124 0.113 0.011 9.3

M9 45.39 49.61 4.22 8.9 .198 .197 .001 .5

M7 22.94 24.00 1.06 4.5 .075 .061 .014 20.6

IH1 .91 .92 .01 1.1 n.a. n.a. n.a. n.a.

MO2 2.47 2.48 .01 .4 n.a. n.a. n.a. n.a.
46 Mercury in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan

Table 3–1. U.S. Geological Survey National Water Information System site-identification numbers 

for locations sampled in the Grand Calumet River/Indiana Harbor Canal and Lake Michigan, 

Lake County, Indiana, August 2001 and May 2002.

[ID, identification; USGS, U.S. Geological Survey; NWIS, National Water Information System]

Sampling-location ID and name

USGS NWIS 

site-identification 

 number

M19 Grand Calumet Lagoons, west USGS413649087171201

M18 East Branch Grand Calumet River headwaters USGS413630087180401

M16 East Branch Grand Calumet River at Bridge St. USGS413632087221601

M14 East Branch Grand Calumet River at Cline Ave. USGS413647087255700

M13 East Branch Grand Calumet River at Kennedy Ave. USGS413650087274201

M12 West Branch Grand Calumet River at Hohman Ave. USGS5536357

M9 West Branch Grand Calumet River at Indianapolis Blvd. USGS413651087285001

M7 Indiana Harbor Canal at Columbus Dr. USGS413822087281601

M6 Indiana Harbor Canal at Lake George Canal USGS413848087284201

M4 Indiana Harbor Canal at Dickey Rd. USGS413919087273201

M2 Indiana Harbor Canal at mouth of Indiana Harbor USGS414003087263300

IH1 Indiana Harbor near industrial intake USGS414050087264401

LM1 Lake Michigan near industrial intake 1 USGS414009087243401

LM2 Lake Michigan near industrial intake 2 USGS413821087223001

MO1 West Branch Grand Calumet River municipal outfall 1 USGS413657087293300

MO2 West Branch Grand Calumet River municipal outfall 2 USGS413659087284701

IO1 Indiana Harbor Canal industrial outfall USGS413858087280501
This report was prepared by the

U.S. Geological Survey Indiana Water Science Center

Indianapolis, Indiana