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Cover: Illustrations of largemouth bass, and yellow perch have been supplied courtesy 

of the Ohio State Environmental Protection Agency.
Sources of Mercury in Sediments, Water, 

and Fish of the Lakes of Whatcom County, 

Washington

By Anthony J. Paulson

Prepared in cooperation with the

Whatcom County Health Department and the

Washington State Department of Ecology

Scientific Investigations Report 2004-5084

U.S. Department of the Interior

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

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

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

Box 25286, Denver Federal Center

Denver, CO 80225-0286

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.

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

reproduce any copyrighted materials contained within this report.

Suggested citation:

Paulson, A.J., 2004, Sources of mercury in sediments, water, and fish of the Lakes of Whatcom County, Washington: 

U.S. Geological Survey Scientific Investigations Report 2004-5084, 98 p.
iii

Contents

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

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

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

Acknowledgments ................................................................................. 3

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

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

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes 

in Whatcom County ................................................................................. 6

Atmospheric Inputs ................................................................................. 6

Deposition of Mercury from Non-Local Atmospheric Sources ........................ 6

Local Atmospheric Sources and Total Mercury Emission Rates ........................ 8

Municipal and Sludge Incinerators ................................................... 8

Chlor-Alkali Plant ........................................................................ 10

Other Mercury Air Sources in Whatcom County .................................... 12

Model of Mercury Deposition to Lakes in Whatcom County from a 

Unit Mercury Emission .................................................................. 12

Estimates of Mercury Deposition to Lakes in Whatcom County from 

Known Sources ........................................................................ 15

Thermal Reduction Company, Inc. Municipal Waste Incinerator ............... 17

Olivine Corporation Municipal Waste Incinerator ................................. 17

City of Bellingham Sewage Sludge Incinerator .................................... 21

Georgia-Pacific Chlor-Alkali Plant ................................................... 21

Summary of Deposition from Local Air Emissions ................................. 22

Tributary Riverine Inputs ........................................................................... 23

Ground-Water Sources ........................................................................... 30

Mercury in Lake Whatcom and Other Lakes in Whatcom County ................................. 31

Sediments .......................................................................................... 31

Surface Sediments ........................................................................... 31

Mercury Sedimentation in Lakes ............................................................ 33

Water Column ....................................................................................... 40

Fish ................................................................................................... 40

Smallmouth Bass .............................................................................. 43

Largemouth Bass .............................................................................. 44

Cutthroat Trout ................................................................................. 46

Yellow Perch ................................................................................. 48

Brown Bullhead .............................................................................. 49

Other Species ................................................................................. 49

Biogeochemical Behavior of Mercury in Lake Whatcom .......................................... 51

Mass Balances of Mercury in Lake Whatcom ...................................................... 52

Suggestions for Future Studies ........................................................................ 53

Summary and Conclusions .............................................................................. 54

References Cited .......................................................................................... 55
iv

Appendix A. Analysis of Mercury in Fish and Assessment of Quality of 

Data Used in the Report ............................................................... 59

Appendix B. Estimates of Atmospheric Deposition to Lakes in Whatcom County for 

Sources Emitting a Hypothetical Unit of Mercury Emission in 

Bellingham, Ferndale, and at the Bellingham Airport .............................. 63

Appendix C. Method for Calculating Missing Flow Data for the Tributaries of 

Lake Whatcom ........................................................................... 72

Appendix D. Analysis of Core Sections and Estimates of Sedimentation Rates in 

Lakes in Whatcom County ............................................................ 73
v

Figures

1. Map showing location of study area and lakes in 

Whatcom County, Washington ............................................................... 2

2. Map showing location of the basins of Lake Whatcom 

and its tributaries, Whatcom County, Washington ....................................... 5

3. Profile showing historical concentrations of mercury in 

ice core from Upper Fremont Glacier, Wyoming .......................................... 7

4. Diagram showing timelines of local atmospheric sources of mercury ............... 8

5. Diagram showing concepts of a simple model of the 

deposition of mercury ........................................................................ 14

6. Map showing location of sources of mercury emissions,

sediment core sampling sites, and solid waste sites, with the 

1996 wind field at Georgia-Pacific meteorological station 

superimposed, Bellingham, Washington ................................................... 15

7. Graphs showing estimates of atmospheric deposition of mercury 

as a function of times of significantly different operations for 

the three basins of Lake Whatcom and Lake Terrell and Fazon 

and Wiser Lakes, Whatcom County, Washington ....................................... 19

8. Hydrographs showing daily mean flows of tributaries to 

Lake Whatcom, Washington, June 2002 – May 2003 .................................... 26

9. Graph showing correlation of total mercury and specific 

conductance in Olsen Creek, tributary to Lake Whatcom, Washington ............... 28

10. Graph showing relation of total organic carbon and total 

mercury to percentage of fines (<0.004 mm) in samples of surface 

sediments collected in 2002 near tributaries and in the three basins 

of Lake Whatcom, Washington ............................................................ 32

11. Graph showing relation of methyl-mercury to total organic 

carbon in samples of surface sediments from the three basins 

of Lake Whatcom, Washington, 2002 ...................................................... 33

12. Profiles showing relation of enrichment ratio of mercury with 

time in sediment cores from the three basins of Lake Whatcom, 

and Lake Terrell and Fazon and Wiser Lakes, Whatcom County, 

Washington, 2002 .............................................................................. 37

13. Bar graph showing historical, pre-1964, peak and recent rates 

of mercury accumulation in core sections from Lake Whatcom, 

Washington .................................................................................... 39

14. Graphs showing estimated partitioning of mercury between the 

dissolved and particulate phases in five samples in the upper 

water column and two samples in the near-bottom water column 

of the three basins of Lake Whatcom, Washington ....................................... 42

15. Graph showing relation of concentration of mercury in fillets 

to total length of smallmouth bass in Lake Whatcom, Washington ..................... 44

16. Graph showing relation of concentrations of mercury in fillets 

to total length of largemouth bass in selected lakes of 

Whatcom County, Washington. ............................................................ 45
vi

Figures — Continued

17. Graph showing relation of concentration of mercury in fillets 

to total length of cutthroat trout in Lake Samish and the 

three basins of Lake Whatcom, Washington ............................................. 47

18. Graph showing relation of concentration of mercury in fillets 

to a conditioning factor for large cutthroat trout in 

Lake Whatcom, Washington ............................................................... 47

19. Graph showing relation of concentration of mercury in fillets 

to total length of yellow perch in Tennant Lake and 

Lake Whatcom, Washington ............................................................... 49

 20. Graph showing relation of concentration of mercury to total 

length of brown bullhead in Lake Whatcom, Washington .............................. 50
vii

Tables

1. Statistics on lakes in Whatcom County, Washington .................................... 4

2. Measured deposition of atmospheric mercury (Hg) in the 

Pacific Northwest, 1997-2002 ............................................................... 6

3. Rate of emission of mercury (Hg) and other characteristics 

related to local sources of mercury in Whatcom County, Washington ............... 9

4. Matrix of confidence category for estimates of mercury (Hg) 

deposition based on source of emission and speciation data ........................... 16

5. Estimates of deposition rates of mercury to lakes in 

Whatcom County from local emission sources, Washington ........................... 18

6. Summary of analyses of water samples from the mouth of the 

tributaries to Lake Whatcom, Washington, July 2002 to May 2003 ..................... 24

7. Concentrations of mercury (Hg) at the terminus of the Nooksack River 

diversion, Whatcom County, Washington, October 2001–August 2003 ............... 28

8. Annual loadings of mercury (Hg) to Lake Whatcom, Washington, 

from tributary inflows, June 2002 – May 2003 ............................................. 29

9. Summary of concentrations and sedimentation rates of mass, 

total organic carbon, mercury (Hg), lead, lead-210, cesium-137, 

and total organic carbon in sediment cores from lakes in 

Whatcom County, Washington ............................................................... 34

10. Summary of analyses of mercury (Hg) in sediment cores from lakes 

in Whatcom County, Washington, September 2002 ....................................... 36

11. Concentrations of total and dissolved mercury (Hg) and 

methyl-mercury in Lake Whatcom, Washington, October 2001 ........................ 41

12. Concentrations of total mercury (Hg) at the intake gatehouse on 

Lake Whatcom, Washington ............................................................... 43

13. Concentrations of total mercury (Hg) and other characteristics of 

largemouth bass and yellow perch collected from Tennant Lake, 

Washington, May 10, 2002 .................................................................. 45

14. Average concentrations of mercury (Hg) and other characteristics 

of cutthroat trout collected from Lake Whatcom and Lake Samish, 

Washington, 2000-01 ........................................................................ 46

15. Average concentrations of mercury (Hg) and other characteristics 

of yellow perch collected from Lakes Whatcom, Padden, Samish, 

and Tennant Lake, Washington, 2000-02 ................................................... 48

16. Average concentrations of mercury (Hg) and other characteristics 

of brown bullhead collected from Lakes Whatcom and Terrell and 

Wiser Lake, Washington, 2000-01 ............................................................ 50

17. Summary of recent annual inputs of sediment and mercury (Hg) 

from known sources to Lake Whatcom, Washington, 1998-2003 ........................ 52
viii

Conversion Factors, Datums, and Abbreviations

CONVERSION FACTORS

Metric to Inch-Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch

millimeter (mm) 0.03937 inch

meter (m) 3.281 foot 

kilometer (km) 0.6214 mile

Area

square meter (m2) 10.76 square foot

square centimeter (cm2) 0.1550 square inch

 0.001076 square foot 

square kilometer (km2) 0.3861 square mile

 247.1 acre

Volume

cubic meter (m3) 264.2 gallon

liter (L) 0.2642 gallon

Flow rate

liter per year (L/yr) 0.2642 gallon per year

Mass

gram (g) 0.03527 ounce, avoirdupois

gram per hour (g/hr) 0.03527 ounce per hour

kilogram (kg) 2.205 pound, avoirdupois

kilogram (kg/d) 2.205 pound per day

megagram (Mg) 1.102 ton, short

Loads

gram per hour (g/hr) 0.0529 pound per day

 19.295 pound per year

Inch-Pound to Metric 

ton per hour (ton/hr) 0.9072 metric ton per hour

mile (mi) 1.609 kilometer

acre 0.4047 hectare

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

pound, avoirdupois (lb) 0.4536 kilogram

pound per year (lb /yr) 0.4536 kilogram per year

ton, short (2,000 lb) 0.9072 megagram (Mg)
ix

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

°F=1.8 °C+32.

DATUMS

Vertical coordinate information is referenced to NGVD29; horizontal coordinate information is 

referenced to the North American Datum of 1983 (NAD 83).

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

ABBREVIATIONS

dscm dry standard cubic meter 

g/kg gram per kilogram

g/ton gram per ton

μg/L microgram per liter

μg/g microgram per gram

μg/kg microgram per kilogram

(μg/m2)/yr microgram per square meter per year

mg/L milligram per liter

(mg/kg) milligram per kilogram

(mg/cm2)/yr milligram per square centimeter per year

ng/L nanogram per liter

ng/mg nanogram per milligram

ng/m3 nanogram per cubic meter

ng/cm2 nanogram per square centimeter

(ng/cm2)/yr nanogram per square centimeter per year

pCi/cm2 picocuries per square centimeter
Abstract

Concerns about mercury (Hg) contamination in Lake 

Whatcom, Washington, were raised in the late 1990s after a 

watershed protection survey reported elevated concentrations 

of Hg in smallmouth bass. The U.S. Geological Survey, the 

Whatcom County Health Department, and the Washington 

State Department of Ecology (Ecology) cooperated to develop 

a study to review existing data and collect new data that 

would lead to a better understanding of Hg deposition to Lake 

Whatcom and other lakes in Whatcom County, Washington.

A simple atmospheric deposition model was developed 

that allowed comparisons of the deposition of Hg to the 

surfaces of each lake. Estimates of Hg deposition derived 

from the model indicated that the most significant deposition 

of Hg would have occurred to the lakes north of the City of 

Bellingham. These lakes were in the primary wind pattern of 

two municipal waste incinerators. Of all the lakes examined, 

basin 1 of Lake Whatcom would have been most affected by 

the Hg emissions from the chlor-alkali plant and the municipal 

sewage-sludge incinerator in the City of Bellingham. The 

length-adjusted concentrations of Hg in largemouth and 

smallmouth bass were not related to estimated deposition rates 

of Hg to the lakes from local atmospheric sources. 

Total Hg concentrations in the surface sediments of Lake 

Whatcom are affected by the sedimentation of fine-grained 

particles, whereas organic carbon regulates the concentration 

of methyl-Hg in the surface sediments of the lake. Hg 

concentrations in dated sediment core samples indicate that 

increases in Hg sedimentation were largest during the first 

half of the 20th century. Increases in Hg sedimentation were 

smaller after the chlor-alkali plant and the incinerators began 

operating between 1964 and 1984. Analysis of sediments 

recently deposited in basin 1 of Lake Whatcom, Lake Terrell, 

and Lake Samish indicates a decrease in Hg sedimentation. 

Concentrations of Hg in Seattle precipitation and in 

tributary waters were used to calculate current (2002-03) 

loadings of Hg to Lake Whatcom. Hg in tributaries contributed 

59 percent of the total Hg, whereas non-local atmospheric 

deposition was estimated to have contributed 41 percent of the 

303 grams of Hg entering Lake Whatcom each year. However, 

these inputs cannot be verified without a better understanding 

of the sources of sediment to Lake Whatcom.

Introduction

Lake Whatcom is a large, natural lake in Whatcom 

County, Washington, near the western edge of the Cascade 

Range foothills (fig. 1). The lake is a source of drinking 

water for about 86,000 Whatcom County residents and 

is used for sport fishing, swimming, and other types of 

recreation. Concerns about mercury (Hg) contamination 

in Lake Whatcom were raised in the late 1990s after a 

watershed protection survey (Serdar and others, 1999) 

reported a concentration of 0.50 μg/g (microgram per gram, 

wet weight) in a composite sample of smallmouth bass fillets. 

For comparison, the national average concentration of Hg is 

0.36 μg/g for sport fish fillets, and 0.34 μg/g for smallmouth 

bass (U.S. Environmental Protection Agency, 1992). Hg 

concentrations in sediment samples also were higher than the 

silt-clay fraction of reference sediments from the Puget Sound 

Basin (Serdar and others, 1999). 

To address concerns about possible Hg contamination in 

Lake Whatcom, Whatcom County Health and Human Services 

Department and the Washington State Departments of Health, 

Ecology, and Fish and Wildlife conducted a second study to 

help determine if consumers of Lake Whatcom fish were at 

risk from Hg exposure (Serdar and others, 2001). The second 

study confirmed that Hg concentrations in smallmouth bass 

from Lake Whatcom were elevated relative to the national 

average concentration. The average Hg concentration was 0.49 

μg/g, whereas the maximum concentration was 1.84 μg/g. 

These concentrations can be compared to the tissue-residue 

criterion of 0.3 μg/g methyl-Hg issued recently by the U.S. 

Environmental Protection Agency (2001).

Environmental managers require information on the 

current loadings of Hg to Lake Whatcom in order to focus any 

future action in an effective manner. Sources of Hg in Lake 

Whatcom are thought to include atmospheric deposition from 

global and local sources, discharges from tributaries (including 

the diversion from the Nooksack River), landfills, dumpsites, 

and local mining operations. Local interest has focused on a 

chlor-alkali plant that operated in the City of Bellingham and 

emitted mercury to the atmosphere from the early 1960s until 

2000. There has been particular interest in assessing the rate 

and speciation of emissions from the chlor-alkali plant and the 

resulting atmospheric deposition of Hg to Lake Whatcom.

Sources of Mercury in Sediments, Water, and Fish of the 

Lakes of Whatcom County, Washington

By Anthony J. Paulson
Purpose and Scope

In 2002, the Whatcom County Health Department 

(WCHD) contacted the U.S. Geological Survey (USGS) 

to evaluate existing data, with the broad objectives of 

determining the presence of Hg in Lake Whatcom and its 

possible sources. During discussions on the scope of the 

project, USGS became aware that the Washington State 

Department of Ecology (Ecology) was planning a survey of 

surface sediments of Lake Whatcom for Hg and also would be 

collecting three sediment cores in Lake Whatcom to determine 

the historical sedimentation of Hg in the lake. In addition, 

Ecology was planning to conduct year-long water sampling 

in 10 tributaries to Lake Whatcom for the analysis of total Hg 

and ancillary physical parameters (pH, specific conductance, 

and total suspended solids) and a statewide survey of Hg in 

sports fish that included several lakes in Whatcom County. 

As both USGS and Ecology began to plan their efforts 

to understand the sources, transformation, and fate of Hg in 

Lake Whatcom, the agencies decided to coordinate sampling 

efforts. A joint Quality Assurance Project Plan (QAPP) was 

developed in which USGS personnel were to assist Ecology in 

the collection of surface-sediment samples and sediment cores 

in Lake Whatcom (Norton, 2002). With the efficiencies gained 

from the joint effort, the USGS was able to collect a core from 

each of five additional lakes in Whatcom County in order to 

assess the regional deposition of Hg in lake sediments. WCHD 

contracted with Ecology to analyze the USGS cores from the 

five other lakes in order to obtain analytical data that were 

consistent with the cores from Lake Whatcom. In addition, 

fish tissue samples were analyzed for Hg concentrations in 

a variety of fish species collected from five other lakes in 

Whatcom County. 

The overall goal of the project reported here was to 

determine the potential sources of Hg to Lake Whatcom and 

other lakes in Whatcom County and the transformation and 

fate of Hg in Lake Whatcom. The more specific objectives for 

this project were as follows:

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Figure 1. Location of study area and lakes in Whatcom County, Washington. 

2 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington
1. Use differences in Hg accumulation rates in other lakes 

in Whatcom County along with other data to infer the 

Hg deposition from known local and regional sources of 

airborne mercury and to determine if accumulation rates 

can be attributed to global sources.

2. Use available data on concentrations of Hg in the tissue 

of fish from Lake Whatcom and other lakes in Whatcom 

County to help identify sources of mercury.

3. Estimate the relative importance of potential sources of 

Hg in Lake Whatcom tributaries and in water diverted 

from the Middle Fork of the Nooksack River by 

examining the relation between concentrations of Hg 

in surface sediments of the lake and the proximity of 

potential sources.

4. Investigate the possibility that geochemical, biological, 

and physical processes occurring in Lake Whatcom or 

in connected wetlands affect the distribution of Hg in 

sediment and fish tissue.

5. Suggest additional sampling or other information needed 

to confirm Hg sources and refine the understanding 

of processes identified after completing the first four 

objectives.

Acknowledgments 

The author is grateful to the following individuals for 

their assistance in completing this study. 

• Stuart Magoon, Karin Fedderson, and Pam Covey 

(Ecology) arranged and managed the contract analysis.

• Dean Momohara, Randy Knox, Sara Sekerak, Sally 

Cull, and Meredith Jones of the Ecology Manchester 

Laboratory conducted the analysis of metals and 

conventional constituents.

• Dean Momohara and Karin Fedderson (Ecology) 

performed quality-assurance review of the radio-dating 

data.

• Karen Payne (USGS) and Dale Norton, Randy Coots, 

Brandee Era-Miller, Morgan Roose, and Dave Serdar 

(Ecology) assisted in collection of the sediment 

and core samples under a wide range of weather 

conditions.

• Joan Vandersypen (Western Washington University) 

provided flow data on several of the tributaries and 

sediment data on Lake Whatcom, and Peg Wendling 

(City of Bellingham) provided data on the operations 

of the Nooksack Diversion and the municipal sewage 

sludge incinerator.

• Art Johnson and Dave Serdar (Ecology) provided 

valuable technical oversight.

• Theresa Olsen (USGS) and Randy Coots (Ecology) 

provided GIS technical assistance.

• C.G. Laird (USGS) input data to the USGS National 

Water Information System (NWIS) database.

• Karen Payne (USGS) managed spreadsheets for initial 

compilation and interpretations of the data used in this 

report.

• Michael Majewski, Mark E. Brigham, and Rick 

Wagner (USGS), Dale Norton (Ecology), and Don 

Vesper (Whatcom County Health Department) 

reviewed the report and provided many valuable 

comments.

Description of Study Area

The surface area of Lake Whatcom covers 20.3 km2, 

and the total drainage area is about 142 km2 (table 1), with 

more than 3,600 housing units, of which about 785 have onsite septic systems (Morris Arthur, Whatcom County Health 

Department, oral commun., 2003). The lake is divided into 

three distinct basins by glacial sills. Basins 1 and 2 (fig. 2) 

are relatively small and shallow (maximum depths of 29 and 

21 m, respectively). Basin 1 is in the most urbanized part 

of the drainage basin, lying largely within the city limits of 

Bellingham, and therefore has few on-site septic systems 

along the shoreline (less than 50 m from the lake). In contrast, 

most of the 198 on-site septic units within 50 m of the lake are 

along the shore of basin 3 between Olsen and Smith Creeks, 

along South Bay to Brannian Creek, and near the outflow of 

Blue Canyon Creek (Morris Arthur, Whatcom County Health 

Department, oral commun., 2003). Basin 3, which has a 

maximum depth of about 103 m, contains 96 percent of the 

lake volume. Several streams drain to Lake Whatcom, and to 

maintain optimal lake levels, water is diverted to the lake from 

the Middle Fork Nooksack River.

After Lake Whatcom, Lake Samish and Baker Lake were 

the largest and deepest of the lakes sampled within Whatcom 

County (fig. 1). Like Lake Whatcom, Lake Samish has a 

highly developed shoreline. In addition, a major interstate 

highway passes adjacent to Lake Samish. Small perennial 

streams that drain into Lake Samish provide only a portion 

of the outflow of the lake. In contrast, the water balance for 

Baker Lake is dominated by flow from 13 creeks draining 

769.2 km2. Fazon Lake, Wiser Lake, and Lake Terrell (referred 

to as the three northern lakes) are small catchment lakes north 

of Bellingham, are surrounded primarily by agricultural and 

forest lands, and have little channelized surface-water inflow. 

Wiser Lake is more developed than either Lake Terrell or 

Fazon Lake, and a major arterial street that bisects Wiser Lake 

permits only limited water exchange between the two parts. 

In contrast, Lake Terrell is part of a wildlife refuge and its 

surface area comprises 24 percent of the area of the drainage 

basin. Tennant Lake also is surrounded by a wildlife refuge. 

The land around Lake Padden (south of Bellingham) has been 

developed as a park and golf course.

Description of Study Area 3
Table 1. Statistics on lakes in Whatcom County, Washington

[Source of data: WCP&DS, Whatcom County Planning and Development Services. km2, square kilometer; m, meter; m3, cubic meter. NA, not applicable; 

–, no data]

Lake Lake area 

(km2)

Drainage 

area

(km2)

Watershed use (percentage of total) Shoreline 

percentage 

developed

Number of 

homes Lake Agriculture Forest Urban/

suburban

Whatcom 

 Basin 1 2.1 – – – – – – –

 Basin 2 1.6 – – – – – – –

 Basin 3 16.6 – – – – – – –

 Total 20.3 142.0 14 1.3 78 7 – –

Terrell 1.8 7.4 – – – – 0 NA

– 133.7 7 50 36 7 – –

Wiser .4 9.7 – – – – 47 30

– 132.3 1.9 80.2 11.7 6 – –

Fazon .1 2.5 – – – – 0 NA

1

8.7 2.2 42 48 7

Samish–east arm 2.8 23.8 – – – – 91 171

 Total for both arms 88.2 195 4 6 88 3 – –

Baker 14.6 769.2 – – – – – –

Tennant .1 2.4 5 78 17 0 0 NA

Padden .6 6.8 – – – – 0 NA

– 115.6 4.2 1.1 49 45 – –

Lake Depth (m) Volume

(107 m3) Inflows Outflows Source of data

Median Maximum

Whatcom

 Basin 1 9 29 1.94 3 gaged one Pelletier, 1998

 Basin 2 11 21 1.80 none – Pelletier, 1998

 Basin 3 54 103 88.4 6 gaged; 1 ungaged – Pelletier, 1998

 Total – – – – – WCP&DS, written commun., 2004

Terrell 2 3 .37 intermittent one ungaged Bortleson and others, 1976

– – – – – WCP&DS, written commun., 2004

Wiser 2 3 .075 intermittent one Bortleson and others, 1976

– – – – – WCP&DS, written commun., 2004

Fazon 3 5 .037 none none Bortleson and others, 1976

Samish–east arm 9 23 2.94 perennial one Bortleson and others, 1976

 Total for both arms – – – – – WCP&DS, written commun., 2004

Baker – 86 13 – Puget Sound Energy, 2002

Tennant .9 1.8 .011 1 ungaged – Dion and others, 1976

Padden 8 18 .53 intermittent one Bortleson and others, 1976

– – – – – WCP&DS, written commun., 2004

1

Drainage area calculations from WCP&DS include drainages downstream of lake.

4 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington
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Figure 2. Location of the basins of Lake Whatcom and its tributaries, Whatcom County, Washington (from Norton, 2004).

Description of Study Area 5
Study Methods

Methods for analyses of Hg in fish reported in this 

document are described in appendix A (at back of report). 

Most data presented in this report were obtained from 

previous studies. All data related to Hg sources or existing 

conditions of fish, water, and sediment in the lakes of 

Whatcom County used in this report were assessed for the 

quality of sampling, processing, and analytical procedures. 

The results of those quality-assurance assessments also are 

included in appendix A. 

Evaluation of Possible Sources of 

Mercury to Lake Whatcom and Other 

Lakes in Whatcom County

Background inputs of aqueous Hg to any body of water 

are determined by deposition from the global reservoir 

of atmospheric Hg. Deposition from local natural and 

anthropogenic sources of atmospheric Hg is added to this 

global deposition. Atmospheric deposition of Hg to land 

surfaces also serves as the initial source of Hg from surfaceand ground-water inputs of Hg. As precipitation containing 

Hg percolates through the aquifer, the Hg can be sequestered 

by organic matter or inorganic minerals. In contrast, 

additional Hg can be released from natural aquifer materials. 

Anthropogenic sources of Hg in ground water could include 

historical application of pesticides on lawns and agricultural 

lands, release from dumps and landfills, or discharges from 

septic systems. Direct precipitation and ground water that 

contain both natural and anthropogenic Hg combine to form 

surface waters. Particulate matter that contains Hg is added to 

these surface waters by runoff from roads and buildings and by 

processes that erode natural geologic formations. In addition, 

precipitation washes various surfaces that may contain Hg, 

such as paint on residential siding, driveways, roads, lawns, 

and motor vehicles. 

Atmospheric Inputs

Deposition of Mercury from Non-Local 

Atmospheric Sources

Accurate, direct measurement of Hg in precipitation 

has been achieved only in the last decade, with the advent 

of ultra-trace analytical techniques combined with the 

sensitive cold-vapor atomic fluoresce spectrometry (CVAFS) 

analysis. Such data are not available for Hg concentrations in 

precipitation or in dryfall in Whatcom County. In 1997, the 

first Pacific Northwest precipitation sampler in the national 

Mercury Deposition Network (MDN) was installed at a 

site located in an open area on the National Oceanic and 

Atmospheric Administration Sand Point facility in Seattle, 

Washington. Annual deposition of total Hg was fairly constant 

at 6.2 μg/m2 between 1998 and 2002 (National Atmospheric 

Deposition Program, 1999, 2000, 2001, 2002, 2003). 

The annual precipitation-averaged concentration of Hg in 

precipitation ranged from about 6 to 10 nanograms per liter 

(ng/L) during 1998-2002 (table 2). In 2001, a precipitation 

sampler was installed on Reifle Island, British Columbia, and 

Table 2. Measured deposition of atmospheric mercury (Hg) in the Pacific Northwest, 1997-2002

[To convert annual deposition to ng/cm2 multiply by 0.1. ng/cm2, nanogram per square centimeter; 

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

Year

Annual deposition 

of Hg

(μg/m2)

Precipitationaveraged 

concentration of 

Hg in precipitation 

(ng/L)

Source of data

Seattle, Washington

1997 17.3 18.3 National Atmospheric Deposition Program, 1998

1998 5.3 5.9 National Atmospheric Deposition Program, 1999

1999 8.0 8.5 National Atmospheric Deposition Program, 2000

2000 6.2 9.8 National Atmospheric Deposition Program, 2001

2001 5.9 6.3 National Atmospheric Deposition Program, 2002

2002 5.7 9.1 National Atmospheric Deposition Program, 2003

Reifle Island, British Columbia

2001 5.5 6.0 National Atmospheric Deposition Program, 2002

2002 3.2 4.8 National Atmospheric Deposition Program, 2003

6 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington
data collected indicated an annual Hg deposition and annual 

precipitation-averaged Hg concentration similar to that at the 

Seattle sampling site. The deposition of Hg at the Seattle and 

Reifle Island sites represents Pacific Northwest deposition 

plus deposition from sources local to the two sites. A Hgdeposition value of 6.2 (μg/m2)/yr is used as an upper limit for 

regional deposition in the Pacific Northwest. 

The annual Hg deposition at the Seattle sampling site 

(17.3 μg/m2) during 1997 (National Atmospheric Deposition 

Program, 1998) was considerably higher than the annual 

Hg deposition from 1998 to 2002. The higher annual Hg 

deposition and precipitation-averaged concentration may 

have been an artifact of the initial start-up of the precipitation 

sampler in 1997, or may have been due to the general decrease 

in Hg deposition with time observed around the world. Hg 

deposition in North America is thought to be decreasing. Hg 

in ice cores from the Upper Fremont Glacier in Wyoming 

(fig. 3) peaked in 1984 (Schuster and others, 2002), whereas 

deposition in upper Midwest peat bogs peaked in the 1960s 

(Benoit and others, 1994). Hg concentrations in recently 

accumulated ice in Greenland also were only 60 percent of the 

Hg concentrations in ice that accumulated between 1940 and 

1960 (Boutron and others, 1998).

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Figure 3. Historical concentrations of mercury in ice core from Upper Fremont Glacier, Wyoming.

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 7
Local Atmospheric Sources and Total Mercury 

Emission Rates

Municipal and Sludge Incinerators

Nationwide, utility and commercial boilers that burn 

coal and municipal and medical waste incinerators contribute 

about 80 percent of the total Hg loading to the atmosphere 

(U.S. Environmental Protection Agency, 1997a). Between 

1974 and 1997, one municipal waste incinerator operated 

continuously within Whatcom County and a second municipal 

incinerator operated intermittently from 1984 to 1997. A 

third incinerator operated in Skagit County, to the south of 

Whatcom County, and its deposition of Hg is considered part 

of the regional deposition. Municipal solid waste contains 

mercury originating from common household items, with 

household batteries being the major contributor (87 percent in 

1989). By 1991, Hg content in all batteries, except button or 

“coin” cells, had decreased from about 1 to 0.025 percentage 

by weight. The Mercury-Containing and Rechargeable Battery 

Management Act was intended to eliminate Hg disposal in 

municipal solid waste after 1996. Similarly, the Mercury 

Chemical Action Plan (Peele, 2003) describes elements of a 

statewide campaign “to virtually eliminate the use and release 

of human-caused mercury in Washington State and take steps 

to further minimize human exposure to mercury.” Hg content 

in paint residues is thought to have peaked around 1975 and 

decreased to insignificant levels by 2000, as a result of the 

1990s ban of Hg in interior and exterior paints. Other sources 

of Hg in municipal solid waste include electrical equipment, 

fluorescent bulbs, personal thermometers, thermostats, dental 

supplies, and special paper coatings. 

The Thermal Reduction Company, Inc. of Ferndale, 

Washington (also known as Recomp, Inc.) started incinerating 

municipal and medical waste in 1974 (fig. 4) with eight 

modular incinerators that provided little pollution control 

(Northwest Air Pollution Authority, Mount Vernon, 

Washington, written commun., 2003). The results of a source 

emissions test in 1985 indicated that the facility was not 

in compliance for emissions of particulate matter. In 1986, 

the eight modular units were replaced with two CS 2000 

incinerator units equipped with an electrostatic precipitator as 

the primary pollution-control device. On December 15, 1988, 

three 2-hour emissions tests were conducted at a burn rate of 

about 4 to 5 tons of waste per hour, with an exit temperature of 

255 °C at the electrostatic precipitator. Hg emissions averaged 

39.7 g/hr (table 3) and between 0.002 and 0.065 percent was 

captured by a filter (AM Test, Inc., Redmond, Washington, 

written commun., 1989). The results of this test indicated an 

average Hg specific-emission release of 9.1 g/metric ton of 

solids burned. In 1993, the air-pollution control device on the 

two-unit incinerator was modernized to include a dry sorbent 

scrubber equipped with a baghouse. Emission tests were not 

conducted between the time the new devices were installed 

and when the incinerator stopped reporting operational data in 

1997. 

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Figure 4. Timelines of local atmospheric sources of mercury.

8 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington
Table 3. Rate of emission of mercury (Hg) and other characteristics related to local sources of mercury in Whatcom County, Washington

[Annual tonnage: Incinerators is in tons of waste burned; chlor-alkali plants is in tons of chlorine produced. Mercury emission: Values in parentheses () are 

estimates described in text section “Estimates of Mercury Deposition to Lakes in Whatcom County from Known Sources.” Form of emitted mercury: RGM, 

reactive gaseous mercury. g/hr, gram per hour. NA, not analyzed; –, unknown]

Source Year Annual 

tonnage Temperature

Mercury 

emission 

(g/hr)

Form of emitted 

mercury

(particulate:RGM: 

vaporous)

References and notes

Incinerators

Thermal Reduction 

Company, Inc.

(municipal waste)

1974-96 – – (39.7) [5:65:30] Emission from 1989 test, 5 percent particulate 

Hg based on particulate violations

1986-92 78,500 256 39.7 [0:70:30] AM Test, Inc., Redmond, Washington, written 

comm., 1989

1992-97 76,900 – (19) [0:62:38] Estimated from reductions in RGM and vaporous 

Hg (van Velzen and others, 2002)

Olivine Corporation

(municipal waste)

1984-90 31,500 – (25) [10:60:30] Hg emissions estimated from Thermal Reduction 

Company’s emission factor

1991-97 43,600 – (25) [0:62:38] Estimated from reductions in RGM and vaporous 

Hg (van Velzen and others, 2002)

City of Bellingham 

(municipal sewage 

sludge)

1974-92 – – (4.5) – Estimated from reductions in RGM and vaporous 

Hg (van Velzen and others, 2002)

1993 – – .0037 Particulate 

emission = 

0.2 percent of 

total

City of Bellingham, written commun., 1993

1993 9,550 – 3.4 – AmTest-Air Quality, Inc., Preston, Washington, 

written commun., 1994 

1993-2002 6,825 – 2.4 – Above test and five days a week operation 

2003 3,622 – 1.16 – Yearly average based on 33 percent usage 

reported in 2002

2003 – – – [0.2:10: 90] Speciation based on estimated chlorine 

concentration

Chlor-Alkali plant

Georgia-Pacific Hypo 

Stack

1975 – – 5.7 [0:100:0] Georgia-Pacific, Inc., written comm., 1975

1981 79,200 9 .0139 [0:100:0] Chris Lee, Georgia-Pacific, Inc., written comm., 

1981

1995 76,700 15 <.0003 [0:100:0] AmTest-Air Quality, Inc., written comm., 1995

Georgia-Pacific hydrogen 

steam from chlor-alkali 

plant

1975 – – 17.9 Unknown Georgia-Pacific, Inc., written comm., 1975

1981 79,200 9 14.8 – Chris Lee, Georgia-Pacific, Inc., written comm., 

1981

1987 90,200 9 17.4 – Ed Dahlgren, Georgia-Pacific, Inc., written 

comm., 1988

1995 76,700 15 22.5 – AmTest-Air Quality, written comm., 1995

Fugitive emissions

Sweden 82,300 Ambient 10.5 [0.05:1:99] Wangberg and others, 2003.

North Carolina – – 21 [NA:2:98] Kinsey, 2003; Landis and others, 2004

Refinery

British Petroleum, 

Cherry Point

2002 – – 0.47 – Sally Otterson, Ecology, Redmond, Washington, 

written commun., 2004

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 9
Olivine Corporation, located on Thomas Road to 

the east of the Bellingham Airport, received conditional 

approval to operate a 50-ton-per-day incinerator in 1984. 

Olivine Corporation received a number of extensions of their 

conditional approval to operate a municipal waste incinerator 

and operated it intermittently through 1990 (reported annual 

hours of operation ranged from 3,650 to 4,050). By March 

4, 1991, a dry sorbent scrubber with a baghouse had been 

installed at the incinerator. Operational data were not available 

for 1988, 1989, and 1993, and Olivine Corporation stopped 

reporting operational data to the Northwest Air Pollution 

Authority in 1998. Hg emission tests were not conducted 

at this incinerator before or after the installation of the dry 

scrubbers. 

The City of Bellingham began incinerating the sludge 

from its Post Point wastewater-treatment plant onsite in 

1973. The primary air pollution control device for this 

incinerator was a tray scrubber, in which water is dripped 

into the stream of exiting gases from the incinerator. With 

the expansion of the wastewater-treatment plant in 1993, the 

air-pollution devices were upgraded to include a wet Venturi 

scrubber and an electrostatic precipitator (Larry Bateman, 

City of Bellingham, oral commun., 2003). On November 4 

and 5, 1993, an atmospheric Hg emission rate was 3.4 g/hr 

at the Post Point wastewater-treatment plant. Simultaneous 

with the emissions test, the Hg content of the sludge being 

incinerated was measured (Am Test-Air Quality, Inc., Preston, 

Washington, written commun., 1994). Hg content of the 

sludge is measured bimonthly and the Hg emissions rates are 

reported annually, based on the 1993 emissions test adjusted 

for changes in the Hg content of the sludge relative to the 1993 

sludge measurements. The average emission rate for 2002 

reported to Ecology was 0.31 g/hr (Sally Otterson, Washington 

State Department of Ecology, oral commun., 2004). 

Chlor-Alkali Plant

Chlor-alkali plants, such as the Georgia-Pacific plant in 

downtown Bellingham, are known to be significant sources 

of atmospheric Hg, and a number of studies have documented 

elevated concentrations of Hg in the air, soils, and vegetation 

near chlor-alkali plants (Maserti and Ferrara, 1991; Ebinghaus 

and Kruger, 1996; and Lodenius, 1998). Hg concentrations 

in soils were elevated by a factor of six near the boundary of 

an Italian chlor-alkali plant compared to background soils 

(Maserti and Ferrara, 1991). Concentrations of Hg in leaves 

of bushes near the chlor-alkali plant were correlated with 

soil Hg concentrations. Hg concentrations in air decreased 

with distance from the plant, and the authors state, “Typical 

background values (3 to 5 ng/m3) are reached within a radius 

of 4 to 5 km from the emission point with an asymmetry in the 

spatial distribution due to the presence of prevailing north and 

north-east winds.” 

In a study of soils near three chlor-alkali plants in 

Europe, Biester and others (2002) suggested that direct uptake 

of atmospheric Hg by foliage and litterfall is one process by 

which Hg is incorporated into forest soils. At one chlor-alkali 

plant, “the highest concentrations were found downwind 

(main wind direction) from the plant in a distance of about 

250 m from the plant.” At the second plant, background Hg 

concentrations were found within 4 km downwind from 

the plant. Biester and others (2002) noted a correlation of 

Hg soil concentrations with landscape cover, soil type, and 

ground elevation of the soils in relation to the elevation of the 

stack of the chlor-alkali plant. The relation with elevation is 

demonstrated in their statement “Moreover, Hg concentrations 

in soils sampled in the valley at distance of more than 500 m 

from the plant rapidly decrease to values near the background, 

whereas Hg concentrations in forest soils on the mountain 

exceed 1,000 μg/kg even at a distance of 1 km.” The intensity 

of their soil sampling allowed an estimate of the total 

inventory of Hg retained in the soils. Only 1 to 2 percent of the 

estimated total atmospheric emissions were found in the soils 

(upper 20 cm) within a distance of 1 km downwind (within a 

90o arc) of three chlor-alkali plants that have been operating 

for 25 to 30 years. 

Near a 10-year-old Cuban chlor-alkali plant, rapid 

decreases in Hg concentrations in soils and vegetation 

also were observed with increasing distance from the site. 

Gonzalez (1991) states “... that from 5 km on, it is not 

possible to find differences in concentrations with respect to 

more remote sites, even along the main wind direction (ENE).” In this location, a lake is located 3 to 15 km upstream of 

the plant, but the lake is downwind along one of the prevailing 

wind directions. Gonzalez (1991) concludes “the dam waters 

are not polluted by Hg, suggesting that the atmospheric 

emissions of Hg by the plant are not significant.”

In the chlor-alkali industrial process, electrolysis is used 

to generate chlorine gas (Cl2) and caustic soda (NaOH) from 

NaCl in a two-step process. The Georgia-Pacific chlor-alkali 

plant in Bellingham went into production with 26 mercury 

electrolysis cells in 1964 with a capacity of 122 tons of 

chlorine per day (Perry, 1974). The capacity of the plant was 

increased by about 50 tons of chlorine per day in late 1977 

with the construction of six additional mercury cells (GeorgiaPacific Inc., Bellingham, Washington, written commun., 

1975). The chlorine production had increased to 220 tons by 

1990 due to more efficient electrolysis.

In the first step of the chlor-alkali process, mercury 

electrolysis cells produced chlorine gas and an intermediate 

sodium-mercury amalgam (Na(Hg)) according to the equation: 

NaCl + Hg => 1⁄2Cl2 + Na(Hg). (1)

10 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Mercury-laden vapors associated with the outlet end 

box and inlet end box on each cell were collected by a fume 

air system under a slight vacuum. The gas passed through a 

water heat exchanger and then through a glycol/water heat 

exchanger. A demister then was used to recover particulate 

mercury from the vapor stream and additional mercury was 

removed from the air in the brine de-chlorination stack. In 

February 1975, the Hg emission rate from the chlorine side 

of the process (fume air system) was 5.7 g/hr. A scrubber 

was installed during the modernization and expansion of the 

plant in the late 1970s. After the modernization, the fume 

air stream passed through this scrubber and was discharged 

through the hypo stack at a temperature of about 23 oC (Ed 

Dahlgren, Georgia-Pacific, Inc., Bellingham, Washington, 

written commun., 1988). In 1981, a mercury source-emissions 

test (Chris Lee, Georgia-Pacific, Inc., written commun., 1981) 

indicated a release of 0.0139 g/hr from the hypo stack. In 

1995, the Hg emission rate from the hypo stack based on test 

results was less than 0.0003 g/hr (AmTest-Air Quality, Inc., 

Preston, Washington, written commun., 1995). 

In the second step of the process, caustic soda was 

produced and mercury was regenerated during the dissociation 

of the sodium-mercury amalgam that was produced during the 

first step:

Although these Hg emission rates reflected the potential 

amount of airborne Hg leaving the chlor-alkali plant, they did 

not reflect the actual atmospheric loading from the GeorgiaPacific industrial complex. During the emission tests in 1975, 

1981, 1987, and 1995, the hydrogen gas stream from the chloralkali plant was directed to the stack for accurate Hg emissions 

measurements. As early as 1972, the hydrogen gas stream 

from the chlor-alkali plant was piped to the nearby lignin 

plant of the Georgia-Pacific paper mill, where the hydrogen 

was burned as an energy source. When accounting for all 

equipment operation rates in the lignin plant from 1971 to 

1999, an estimated 80 to 85 percent of the hydrogen produced 

by the chlor-alkali plant was burned in the lignin plant spray 

dryers [(Roger J. (Chip) Hilarides, Georgia-Pacific, Inc., oral 

commun., 2003]. 

The hydrogen line that ran from the chlor-alkali plant to 

the lignin plant was uninsulated and unheated. Seven traps 

were placed in the line to collect condensed elemental Hg. 

The line generally was at ambient temperature or lower. As 

a result, there were periodic operational problems associated 

with freezing of residual moisture in the line during the 

winter. The maintenance crews replaced the traps in the late 

autumn and put steam heat through the lines to keep the traps 

warm during cold spells. Chlor-alkali plant cell renewers and 

maintenance personnel routinely drained elemental Hg from 

these hydrogen line traps and returned it to the plant for reuse. 

The exact amount or frequency of the Hg recovered from 

the hydrogen line was not documented. According to facility 

maintenance personnel, about 10 lb of Hg was recovered 

from each of seven traps that were drained each autumn. 

Additionally, during the course of the year, six other traps 

(three on the chlor-alkali plant side and three on the lignin 

plant side) were drained twice a month of about 10 lb of Hg, 

or a total of 240 lb/yr from these traps. Therefore, by the 

estimate of Georgia-Pacific, Inc., personnel, 310 lb of liquid 

mercury were removed each year from the hydrogen line to the 

lignin plant (Roger J. (Chip) Hilarides, oral commun., 2003), 

which reduces the Hg loading to the lignin plant by 16.1 g/hr. 

This estimate of Hg drained from the line is larger than the 

flow of Hg entering the line in hydrogen stream as measured 

by the 1981 Hg emission test and represented at least a 70-

percent reduction to the Hg loading to the lignin plant for the 

other three Hg emission tests. Although the amount of Hg 

estimated to have been collected in the line to the lignin plant 

may have been too high, most of the Hg going to the lignin 

plant during the winter months probably condensed in the line 

and was collected by Georgia-Pacific, Inc., personnel, thus, 

most of the Hg measured during the stack test did not enter the 

atmosphere. 

After being generated in the decomposers, hydrogen 

gas containing some Hg vapor passed through several heat 

exchangers to reduce the temperature to between 8 and 15 oC, 

at which point Hg condenses and drops out of the gas stream. 

Hg vapor concentrations decrease with decreasing temperature 

of the air stream if the Hg vapor is in equilibrium with the 

glycol-cooled hydrogen heat exchanger. In the final stage of 

pollution control, the hydrogen gas passes through a demister 

to reduce particulate Hg in the air stream before exiting the 

hydrogen stack (Ed Dahlgren, Georgia-Pacific, Inc., written 

commun., 1988; Cazzaro, 2002). A Hg source test in 1975 

indicated an emission rate of 17.9 g/hr from the hydrogen 

stream. A second demister was added to the hydrogen stack 

during the late 1970s expansion and renovation. In the late 

1970s, the graphite anodes were replaced with titanium 

anodes, which are thought to reduce Hg emissions from chloralkali plants due to reduced maintenance. Three emission tests 

of the hydrogen stream were performed at the Bellingham 

Georgia-Pacific chlor-alkali plant between 1981 and 1995 

(table 3) and indicated a release of between 14.8 and 22.5 g/hr, 

depending on production rate and outlet temperature.

1

(1)

Na(Hg) + H2O => NaOH + 1⁄2H2 + Hg. (2)

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 11 
The third source of Hg is general evasion of solid Hg 

from the Hg electrolysis cell room. If the operator follows the 

general housekeeping rules outlined in Review of National 

Emission Standards for Mercury (U.S. Environmental 

Protection Agency, 1984), an Hg emission rate of 1.3 kg/d 

can be assumed (40 CFR 61 Subpart E). The Hg emission rate 

from the mercury cell room at the Georgia-Pacific plant in 

Bellingham was never measured. Hg emission rates from cell 

rooms of chlor-alkali plants are difficult to measure and have 

been measured with modern analytical instrumentation only at 

a few plants. At a Swedish chlor-alkali plant built in 1924 with 

a chlorine production similar to that of the Bellingham plant, 

the Hg emissions from the cell house averaged 10.5 g/hr in 

2001 (Wangberg and others, 2003). However, little information 

about the operation of the Swedish plant is given except that 

plant-reported Hg emissions per metric ton of chlorine were 

less than the European average. The emission rate of Hg from 

the cell room of a North Carolina chlor-alkali plant under 

controlled conditions was 21.6 g/hr (Kinsey, 2003). These 

measured Hg emission rates are considerably less than the 

U.S. default emission rate (51.6 g/hr) listed in 40 CFR 61 

Subpart E. Given the differences in industrial processes and 

institutional controls, caution is advised when generalizing the 

Hg emissions on the basis of data from different chlor-alkali 

plants. Even within a single plant, Hg emission rates may 

vary over short periods due to variable operational schedules 

(routine versus invasive maintenance). The Hg emission rates 

between similarly equipped plants also are probably affected 

by the diligence of the operators and the maintenance of 

industrial and pollution devices.

Other atmospheric releases of Hg may be associated 

with the handling of clarifier solids from the treatment of 

wastewater generated from the Georgia-Pacific chlor-alkali 

plant and stockpiling of brine sludge in the early 1970s. 

Brine sludge was stockpiled in an impoundment basin until a 

recovery system was developed in 1973. The initial method 

of treatment was roasting the brine sludge and recovering the 

Hg in condensers. About 9.5 g/hr of Hg left the condensers, 

where 90 percent was removed (Perry, 1974). The 1 g/hr of 

Hg leaving the stack that originated from the roasting of brine 

sludge would not have been included in the total Hg emissions 

that were measured in 1975. Roasting was abandoned in late 

1974 in favor of chemical stabilization. 

Georgia-Pacific personnel (Roger J. (Chip) Hilarides, 

oral commun., 2003) verified that wood burned in the hog fuel 

burner was not contaminated with Hg. Burning of wood waste 

and old clarifier sludge was reported in the 5000 block of 

Everson-Goshen Road in 1979 (Glen Hallman, Northwest Air 

Pollution Authority, written commun., December 3, 1979; Bob 

Bishop, Washington State Department of Ecology, Olympia, 

Washington, written commun., December 7, 1979). 

Other Mercury Air Sources in Whatcom County

 The estimate of the Hg emissions from the Cherry 

Point refinery west of Ferndale was 0.47 g/hr for 2002, based 

on production rates and emission factors (Sally Otterson, 

written commun., 2004). Hg emissions from the release of 

dental fillings (about 1 mg/body) during the cremation of 

bodies (U.S. Environmental Protection Agency, 1997a) are 

not further considered. Although cement plants had operated 

in Whatcom County, they had closed by the 1970s before 

air emission measurements were required, and therefore the 

historical emissions from cement plants will not be assessed 

and considered. Mercury is not included in the Ecology’s 

Toxic Release Inventory and Hazardous Waste databases for 

the Intalco aluminum smelter or a second refinery at Ferndale.

Model of Mercury Deposition to Lakes in 

Whatcom County from a Unit Mercury Emission

There is considerable debate in the scientific literature 

as to whether deposition of Hg to lakes is a result of global or 

local sources (Hanisch, 1998). “Assuming constant emission 

rates, the quantity of mercury deposited on a regional and 

local scale can vary depending on source characteristics 

(especially the species of mercury emitted), meteorological 

and topographical attributes, and other factors” (Expert Panel 

on Mercury Atmospheric Processes, 1994). Hg emitted to the 

atmosphere in the vapor phase (Hgo) generally will remain 

in the atmosphere between 6 months and 2 years (Fitzgerald, 

1989; Lindqvist, 1994). The residence time of Hg in the 

atmosphere reflects a combination of direct diffusion into 

water and the oxidation to Hg(II), which is rapidly removed by 

rainfall and dryfall. Therefore, local Hg sources emitted to the 

atmosphere in the Hgo form will likely not result in significant 

increases in near-field deposition of Hg, but will simply add to 

the global atmospheric pool. 

Only Hg emitted in the particulate or oxidized (Hg(II)) 

reactive gaseous mercury (RGM) forms are likely to be 

deposited in significant amounts near the source. The 

atmospheric residence time of particulate-phase mercury is 

on the order of about a week (Pacyna and others, 1996). An 

estimated 5 to 10 percent of the initial reactive Hg emissions is 

deposited within 100 km of the sources (U.S. Environmental 

Protection Agency, 1997b). Contact with ground vegetation 

results in removal of atmospheric reactive Hg. However, 

methods to quantify this removal are difficult. Scavenging 

parameters based on vertical gradients of atmospheric Hg 

suggest removal mechanisms of Hg that are similar to those of 

nitric acid; however, Lindberg and Stratton (1997) state, “it is 

not possible [to] prove whether the concentrations gradients 

are statistically significant.” The deposition of particulate or 

reactive forms of Hg is known to be influenced by rainfall.

12 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Although single rainfall events have been known to 

remove one-half the RGM, the relatively uniform rainfall 

concentrations across southern Florida have been interpreted 

to mean that scavengable Hg (that is, RGM) is uniformly 

distributed on the time scales (residence times) of days to 

weeks during the wet season (Guentzel and others, 2001). In 

the absence of significant upwind local sources of particulate 

or reactive Hg, the direct deposition of Hg to the surfaces of 

lakes in the greater Bellingham area will be similar. 

Data are not available on the forms of atmospheric Hg 

in the gases emitted by sources in Whatcom County or on the 

concentrations and forms of Hg in air masses above lakes of 

interest in Whatcom County after major Hg emitters began 

operating. Most of the worldwide effort in characterizing the 

speciation of Hg for atmospheric sources has concentrated 

on major energy-combustion sources, such as coal-fired 

electrical plants. A literature search indicated only two studies 

in which the forms of Hg emitted from the Hg electrolysis 

cell rooms of chlor-alkali plants were determined, and only 

one study in which the forms of Hg emitted by a municipal 

waste incinerator were investigated. Because the forms of Hg 

in a gas stream depend on the complex interaction between 

materials and industrial processes, the operations of a specific 

plant may affect the forms of Hg being emitted. Given the 

paucity of total Hg emission data for major Hg sources in 

Whatcom County, the lack of any local speciation data, and 

few worldwide measurements of Hg speciation for the types 

of plants operating in Whatcom County, a simple model that 

provides a rough estimate of Hg deposition for the emission 

sources described above is warranted, rather than applying a 

complex model with numerous input terms for which local 

data are not available.

A simple model based on first principles was developed 

for this project and is described in appendix B (at back 

of report). The model is used primarily to estimate, in 

a consistent manner, the deposition of Hg to lakes in 

Whatcom County from among past local sources of Hg. 

The simplifications of the plume dynamics allow use of an 

analytical solution to estimate the deposition rate without 

having to numerically estimate the concentration of each 

Hg species, i, in the air mass. Deposition to the aquatic and 

terrestrial surfaces depends primarily on the reactivity constant 

for species i, - ki, which is the measure of how fast Hg is 

removed from the atmosphere and is inversely proportional 

to the atmospheric half-life of each species. In the model, 

the deposition of the three forms of Hg (vaporous elemental, 

reactive gaseous, and particulate) initially emitted from a 

source are considered independently, and the total deposition 

is the sum of the deposition of the three species (Depi).

where

Qi,0 is the emission of species i from the source,

x is the distance between the source and lake of interest, 

and

u is the wind speed, and α is the angle of the plume 

dispersion.

The only simplification of the model is that the Hg from 

the source laterally disperses across the width of the plume 

as defined by tan(α) • x. Equation 3 can be broken down 

into terms that easily relate the emissions rate to transport 

concepts (fig. 5). The Qi,0 /u represents the dilution of the 

emission source of species i by the wind field, much as the 

initial concentration of a pollutant in a river resulting from 

a point source discharge is dependent on the velocity of a 

river. The term e-ki /u • x represents the decrease in the transport 

of the Hg species with distance from the source resulting 

from the deposition of species i between the source and 

distance x. The term 1/ (tan(α) • x) represents the decrease 

in the concentration of species i in the plume, and therefore 

deposition over an area, by the lateral dispersion of the plume 

with distance from the source. In most cases, deposition is 

independent of the plume angle. As the degree of lateral 

dispersion is increased (increasing α), the hourly deposition 

at a given site under a given plume will decrease. Because 

deposition will occur over a greater area, the number of hours 

that a given site is under a plume will increase. Only when a 

site is in a zone of wind shear will deposition be dependent on 

α. Note that the deposition also is independent of the thickness 

of the plume. Although expanding the thickness of the plume 

will decrease the concentration of species i in the plume, 

deposition will occur over a taller air column. 

Depi

ki Qi� 0e

-

ki

u

--- � x

�

�u � tan� � � � x� = --------------------------------------

, (3)

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 13 
Given a specific wind field, deposition at a given point 

from the source was calculated knowing the emission rate of 

species i (Qi,o) and the inverse of the half-life (ki). The model 

was applied using hourly wind speed and wind direction data 

from the Georgia-Pacific (G-P) Bellingham meteorological 

site (Axel Franzmann, Northwest Air Pollution Authority, 

oral commun., 2003) during 1996 because the wind data for 

1995, the year of the last emission test, were incomplete. If the 

plume was above the target receptor (target-receptor direction 

is within wind direction ± 1⁄2α), direct deposition of Hg to 

the site (fig. 6) was calculated for that hour. Deposition for a 

unit emission of Hg (Qo = 1 g/hr) for an atmospheric half-life 

of 1 day, 1 week, 1 month, 1 quarter-year, and 1 year was 

calculated using equation 3 with the measured wind speeds at 

the Bellingham site, the distance from the source to the target 

receptor (from table B1 in appendix B), and a standard plume 

angle (α) of 20 degrees (table B1 and figs. B1-B2 in 

appendix B). 

The deposition rates to target core sites in the eight lakes/

basins are described in appendix B for unit emissions of Hg 

(1.0 g/hr) for Hg species with a range of half-lives. The total 

deposition of Hg (TotDep) to the water surface was calculated 

as the sum of the depositions from three species:

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Figure 5. Concepts of a simple model of the deposition of mercury. 

(See the accompanying text for explanation of symbols.)

where 

DepP is the deposition of particulate mercury, 

DepR is the deposition of reactive Hg, and

DepV is the deposition of vaporous mercury.

(1)

(2)

(3)

TotDep = DepP + DepR + DepV, (4)

14 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Estimates of Mercury Deposition to Lakes in 

Whatcom County from Known Sources

The model deposition rates for a unit Hg source under a 

variety of residence times provided in appendix B allow for 

the calculation of estimated total deposition to any of the eight 

lakes/basins in Whatcom County from a source at any of three 

locations: downtown Bellingham, Ferndale, or Bellingham 

airport. This calculation requires knowledge of the Hg 

emission rate to the atmosphere, the form of Hg in the plume 

once it was cooled to ambient temperatures, and the residence 

time of each of the three species. Minimum and maximum 

estimates were made by varying the residence times within the 

range reported in the literature. Residence times used ranged 

from 1 day to 1 week for particulate Hg; 1 week to 1 month 

for reactive Hg, and 3 to 12 months for vaporous Hg. These 

times reflect the overall residence of a specific species once 

emitted to the atmosphere from a source, even though there 

may be some conversion among species (for example, the 

oxidation of vaporous Hg to Hg(II) proceeds slowly before 

the Hg(II) is more rapidly removed from the atmosphere by 

rainfall).

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Figure 6. Location of sources of mercury emissions, sediment core sampling sites, and solid waste sites, with the 1996 wind field 

at Georgia-Pacific meteorological station superimposed, Bellingham, Washington. 

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 15 
The same meteorological data sets and the same 

assumptions about the reactivity of the various forms of 

atmospheric Hg were applied consistently across Hg sources 

and receptor sites. The model required total Hg emissions data 

and the speciation of Hg from that specific source. Confidence 

in the model estimates was categorized on the basis of the 

quality of the best available data used in the estimates 

(table 4). Simulations were assigned to 

• Category A if both Hg emission and speciation data 

were available for a source in Whatcom County. 

• Category B when actual total Hg emissions data from 

the source and speciation data from the literature for 

the specific type of source were used. 

• Category C when total Hg emission rates from another 

source of similar type and speciation data from the 

literature for the type of source were used. 

• Category D when actual emission data were used and 

the Hg speciation was estimated from the actual air 

chemistry of the source gases. 

• Category E when actual total Hg emissions were 

used and the speciation was estimated on the basis 

of concentrations of constituents other than Hg in 

the emissions gases obtained from the literature for 

facilities of the same type.

Table 4. Matrix of confidence category for estimates of mercury (Hg) deposition based on source of emission and speciation data

[Emission Data: Category C emission data for Thermal Reduction Company, Inc., were generated from the category B emission data and 

changes in Hg emission due to changes in control devices. Category F emission data for the City of Bellingham sewage sludge incinerator were 

generated from the Category E estimates and changes in Hg emission due to changes in control devices. –, no instances of speciation/emission 

combination]

EMISSION DATA

Total emissions measured Estimated from changes 

in control devices

Similar type of 

facility measured

SPECIATION DATA

Speciation measured Category A:

none

 – –

Similar type of facility measured Category B:

1) Thermal Reduction 

Company, Inc.; 

1986-92

 – Category C: 

1) Georgia-Pacific fugitive 

emissions from cell room 

2) Olivine Corp.; 1984-90

Estimated from change in 

control devices from measured 

speciation with similar type of 

facility 

 – Category C:

2) Thermal Reduction 

Company Inc.; 

1974-85

2) Thermal Reduction 

Company, Inc.; 

1993-97

Category D: 

1) Olivine Corp.; 1991-97

Estimated from measured air 

chemistry

Category D: GeorgiaPacific fume air – –

Estimated from estimated air 

chemistry

Category E: City of 

Bellingham sewage 

sludge incinerator; 

1993-present

Category F:

1) City of Bellingham 

sewage sludge 

incinerator; 1974-

1993

 –

No air chemistry information – No estimates made:

1) Georgia-Pacific 

hydrogen stream

No estimates made: 

1) Cherry Point oil refinery, 

British Petroleum

16 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
A change in operation and(or) the extent of abatement 

of atmospheric emissions occurred during the operations of 

all major Hg sources in Whatcom County (fig. 4). Changes in 

Hg deposition to lakes in Whatcom County were assessed as 

a result of these improvements in operations. Species-specific 

adjustments in Hg emissions published in the literature were 

used to estimate Hg emissions either before or after the 

installation of a specific type of air-pollution control device. 

When species-specific efficiencies of air-pollution control 

devices from the literature were used to adjust the species 

emission rates as a result of changes in operations, confidence 

in the simulation was downgraded one category. 

Thermal Reduction Company, Inc. Municipal Waste 

Incinerator

The 1988 Hg emission test for the Thermal Reduction 

Company, Inc., municipal waste incinerator (MWI) (39.7 

g/hr or 9.1 g/metric ton of Hg of waste burned) was used 

to estimate Hg deposition for the period when the two 

modules were equipped with only an electrostatic precipitator 

(1986–92). The one measurement in the hot flue gas of a 

MWI indicates that 70 percent of the Hg is emitted in the 

reactive form (Prestbo and Bloom, 1995) because chlorine 

gas, originating from the burning of plastics (for instance, 

vinyl chlorides) stabilizes the Hg as Hg(II). Electrostatic 

precipitators only are effective for particulates and not for 

reactive or vaporous Hg (van Velzen and others, 2002), 

and therefore the remaining 30 percent was assumed to 

be vaporous Hg (Category B simulation). The maximum 

estimate of Hg deposition to Lake Whatcom from the Thermal 

Reduction Company, Inc., MWI from 1986 to 1992, based 

on the lower bounds of residence times for each Hg species, 

ranged from 0.77 (μg/m2)/yr at the basin 1 coring site to 0.30 

(μg/m2)/yr for the basin 3 coring site (table 5, fig. 7A). In 

contrast, the maximum estimate of Hg deposition to the three 

northern lake sites from 1986 to 1992 ranged from 3.6 to 4.7 

(μg/m2)/yr, with 99 percent of the deposition originating from 

the RGM emissions (fig. 7B).

Dry sorbent injection and filtration through a baghouse 

(fiber filter) was estimated to reduce RGM emissions by 50 

percent and vaporous Hg emission by 30 percent (van Velzen 

and others, 2002). For the Thermal Reduction Company, 

Inc., MWI, the Hg emissions from 1993 to its closure were 

estimated to be 5 g/metric ton or 19 g/hr with RGM decreasing 

to 62 percent of the total emissions. The deposition model 

indicated that the installation of the pollution devices in 1993 

reduced Hg deposition from the Thermal Reduction Company, 

Inc. by more than 50 percent, with the contribution from RGM 

decreasing to 95 percent of the total deposition to lakes in 

Whatcom County (Category C). 

Because particulate emissions were high during earlier 

operation of the eight smaller module units for Thermal 

Reduction Company, Inc. (1974–85), Hg could have 

condensed on the large mass of particles that was emitted. To 

account for higher particulate air emission during the earliest 

stage of operations, an estimate of 5 percent of the total Hg 

emissions (Category C) measured by the 1988 source test was 

modeled as particulate Hg, based on general knowledge of 

the efficiencies of air-pollution control devices. This change 

increased maximum estimated Hg deposition to lakes in 

Whatcom County by about 30 percent to 1.0 (μg/m2)/yr for 

the basin 1 site because particulate Hg is deposited nearer the 

source than RGM.

Olivine Corporation Municipal Waste Incinerator

Hg emissions tests were not conducted at the Olivine 

Corp. facility either before or after the installation of the dry 

injection sorbent with baghouse filtration in 1991. Between 

1984 and 1990, when the Olivine Corp. municipal waste 

incinerator was operating with only a fabric filter, data on the 

amount of waste burned and the number of hours of operation 

could be documented only for the years 1984 and 1990; those 

data indicated a burn rate of about 10 ton/hr while operating 

40 percent of the time. The Hg content of the municipal waste 

from Olivine Corp. incinerator was assumed to be the same 

as that of the Thermal Reduction Company Inc., incinerator 

during the 1988 emission test. Because air-pollution devices at 

both facilities prior to the installation of dry injection sorbents 

were ineffective in removing RGM and vaporous Hg, the 

Hg emission rate per ton for the Olivine Corp. incinerator 

was estimated to be 9.1 g/metric ton, from the 1988 Thermal 

Reduction Company Inc., emission test, which converts to an 

annual average of 25 g/hr (Category C). Because the Olivine 

Corp. incinerator was operating under a conditional approval 

with a fabric filter and no emission tests of any kind were 

conducted, problems with particulate emissions were assumed 

to be the same as that of the earlier Thermal Reduction 

Company, Inc., operations. Particulate Hg emissions were 

estimated to contribute 10 percent of total Hg emissions, with 

60 percent in the reactive form, and 30 percent in the vaporous 

form. The maximum deposition of Hg to Lake Whatcom basin 

1 sediment coring site from the Olivine Corp. incinerator 

was estimated to have been 1.2 (μg/m2)/yr, with 50 percent 

originating from deposition of particulate Hg with a residence 

time of 1 day. Maximum deposition for the northern lakes 

ranged from 2.3 (μg/m2)/yr for Lake Terrell to 6.4 (μg/m2)/yr 

for Fazon Lake.

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 17 
Table 5. Estimates of deposition rates of mercury to lakes in Whatcom County from local emission sources, Washington

[All values are given in micrograms per square meter per year [(μg/m2)/yr]. Minimum estimates are based on the upper bound (longer) within the range of 

residence times for each species, while maximum estimates are based on the lower bound (shorter) within the range of residence times for each species (to 

convert annual deposition to (ng/cm2)/yr multiply by 0.1). (ng/cm2)/yr, nanogram per square centimeter per year; g/hr, gram per hour]

Lake Whatcom Lake 

Samish

Baker 

Lake

Fazon 

Lake

Lake 

Terrell

Wiser 

Lake

Confidence 

category 

Basin 1 Basin 2 Basin 3 (see table 4)

Georgia-Pacific Chlor-Alkali Plant1

Fume Air System Before Modernization

Minimum 0.63 0.18 0.06 0.07 0.02 0.14 0.08 0.05 D

Maximum 2.7 .77 .24 .28 .08 .56 .31 .21 D

Fugitive Emissions from Mercury Cell Room

Minimum using 10 g/hr emission 0.11 0.03 0.01 0.01 0.00 0.02 0.01 0.01 C

Maximum using 20 g/hr 

emission

1.03 .29 .10 .11 .03 .22 .12 .08 C

Thermal Reduction Company, Inc., Municipal Waste Incinerator

Minimum: 1993-97 0.08 0.07 0.03 0.08 0.04 0.63 0.38 0.48 C

Maximum: 1993-97 .32 .27 .13 .30 .12 2.0 1.5 1.9 C

Minimum: 1986-92 .19 .17 .08 .19 .09 1.5 .89 1.1 B

Maximum: 1986-92 .77 .65 .30 .72 .29 4.7 3.6 4.5 B

Minimum: 1974-85 .72 .61 .28 .67 .27 4.4 3.3 4.2 C

Maximums: 1974 -85 1.0 .86 .39 .92 .36 6.8 5.1 6.2 C

Olivine Corporation Municipal Waste Incinerator

Minimum: 1991-97 0.15 0.12 0.06 0.14 0.05 0.79 0.31 0.51 D

Maximum: 1991-97 .68 .38 .27 .56 .19 3.5 1.3 2.2 D

Minimum:1984-90 .25 .17 .10 .22 .08 1.3 .50 .83 C

Maximum: 1984-90 1.2 .61 .42 .85 .26 6.4 2.3 3.7 C

City of Bellingham Sewage Sludge Incinerator

Maximum in 2003 0.10 0.03 <0.01 0.01 <0.01 0.02 0.01 0.01 E

Maximum After 1993 Expansion .21 .06 .01 .02 .01 .04 .02 .02 E

Maximum Before 1993 

Expansion

.42 .13 .04 .05 .01 .10 .05 .03 F

Total Deposition Based on Maximum Estimates

1964-74 3.75 1.06 0.34 0.39 0.12 0.78 0.43 0.29

1974-84 2.50 1.29 .53 1.08 .41 7.12 5.23 6.33

1986-91 3.41 1.68 .85 1.73 .61 11.44 6.05 8.29

1993-97 2.24 1.00 .49 .99 .36 5.72 2.98 4.16

1997-2000 1.24 .35 .10 .13 .04 .26 .14 .10

2000-2002 .21 .06 <.01 .02 .01 .04 .02 .02

2003 .10 .03 <.01 .01 .01 .02 .01 .01

1

Does not include hydrogen gas stream.

18 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure 7. Estimates of atmospheric deposition of mercury as a function of times of significantly different operations for 

the three basins of Lake Whatcom and Lake Terrell and Fazon and Wiser Lakes, Whatcom County, Washington. 

Emissions from Georgia-Pacific chlor-alkali plant does not include hydrogen stream. Times of significantly different 

operations are shown in figure 4.

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 19 
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Figure 7.—Continued.

20 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
After the lime injection scrubber was installed at the 

Olivine Corp. incinerator in 1991, between 30,000 (1992 

and 1997) and 39,800 tons (1996) of municipal waste were 

reported to have been burned while operating between 40 and 

94 percent of the time, with no data reported for 1993. A burn 

rate of 9 metric ton/hr was assumed in 1996 for the hours of 

operation because tonnage of waste burned was not reported. 

Like the calculations for Thermal Reduction Company, Inc., 

the emission rates were estimated based on the efficiencies 

of lime injection sorbent in removing RGM and vaporous 

Hg according to (van Velzen and others, 2002) (Category D). 

Even though the Hg emission per ton was reduced to about 

5 g/metric ton after installation of the lime injection system, 

the annual average of metric tons burned increased. Although 

the average Hg emission remained at 25 g/hr, the percentage 

of Hg in the RGM decreased to 63 percent, with the 

remainder emitted as vaporous Hg. The assumed elimination 

of particulate Hg emission shifts the dominant depositional 

species to RGM, which accounts for 95 percent of the Hg 

deposition. The maximum Hg deposition to all lakes using this 

change in speciation is estimated to reduce deposition between 

1991 and 1997 by about 40 percent less than the 1986–91 

levels (figs. 7A and 7B).

City of Bellingham Sewage Sludge Incinerator

The speciation of Hg in the City of Bellingham sewage 

sludge incinerator was not measured. In a German study, 

sewage sludge was amended with chlorine-rich solids and 

fluids to achieve an average chlorine content between 0.15 and 

0.5 percentage by weight (Saenger and others, 1999). When 

the average Cl content in the incinerated sludge was less than 

0.2 percentage by weight (dry weight basis), the percentage of 

Hg in the vaporous state in the flue gas increased substantially. 

With increasing chlorine content of the incinerated sludge, the 

loss of vaporous Hg presumably was balanced by an increase 

in RGM due to the stabilization of Hg by Cl in the flue gas, 

as has been observed with MWI flue gas. Thus, the chlorine 

chemistry of the sludge and incinerator flue gas is needed to 

accurately estimate Hg speciation in the absence of measured 

values. Data on chlorine chemistry were not available for the 

City of Bellingham sewage sludge incinerator. Hydrochloricacid emission factors for flue gas in municipal sewage sludge 

incinerators (U.S. Environmental Protection Agency, 1995) 

have been estimated to be about 0.003 percentage of Cl by 

wet weight, based on little empirical data. This compares 

to 0.3 percentage of Cl by wet weight in municipal waste 

incinerators. Therefore, the percentage of Hg in the RGM form 

in sewage-sludge emission is likely much less than the 70-

percent RGM found for municipal waste incinerators. Given 

the knowledge of the operation of the City of Bellingham 

sewage sludge incinerator and its air-pollution devices, the 

estimated maximum percentage of Hg emissions as RGM was 

10 percent (0.34 g/hr) and the estimated maximum percentage 

of Hg emissions as particulate Hg was 0.2 percent (table 3). 

The estimated maximum present-day (2003) Hg deposition 

to Lake Whatcom basin 1 from the municipal sewage sludge 

incinerator operating at 33-percent capacity was 0.10 

(μg/m2)/yr (Category E), with 55 percent of the deposited Hg 

originating from emissions of RGM. Estimated maximum 

deposition to the three northern lakes ranged from less than 

0.01 to 0.02 (μg/m2)/yr.

Air emissions of Hg from the City of Bellingham sewage 

sludge incinerator before the expansion of the plant in 1993 

probably were higher than present-day (2003) emissions 

because the tray scrubber was not as efficient as the Venturi 

scrubber at removing reactive gaseous and particulate Hg. To 

account for the less efficient pollution-control devices prior 

to 1993, when the tray scrubbers were the only air-pollution 

control devices, estimated maximum RGM emissions were 

three times higher than present-day (2003) RGM emissions. 

Likewise, estimated maximum particulate Hg emissions 

were twice as high as present-day particulate emissions. 

Because both tray scrubbers and Venturi scrubbers are 

inefficient at removing vaporous Hg, estimated vaporous Hg 

emissions before modernization were only 10 percent higher 

than present-day (2003) emissions (Category F). Estimated 

maximum Hg deposition to Lake Whatcom basin 1 was 0.42 

(μg/m2)/yr, and the estimated maximum deposition for the 

northern lakes was 0.10 (μg/m2)/yr.

Georgia-Pacific Chlor-Alkali Plant

Atmospheric Hg was emitted from three major sources 

at the Georgia-Pacific facility: the hypochlorite side of the 

chlor-alkali process (also known as fume air source), Hg 

hydrolysis cell room emissions, and the alkali side of the 

chlor-alkali process that generates hydrogen gas. Although 

three measurements of the fume air emissions were made, 

only the 1975 emission of 5.7 g/hr was significant. The 1975 

measurement was assumed to be 100 percent in the RGM 

form (Category D) because (1) this gas stream originated from 

the part of the plant where hypochlorite was produced and 

could have easily reacted with Hg to form RGM, and (2) the 

greater-than-99-percent reduction in the Hg emission from 

this stream after the installation of the scrubber in the path of 

this air stream strongly indicates a form that effectively was 

removed by the scrubbers. If Hg was in the vaporous form, 

the installation of the scrubbers would not have caused such 

an effective reduction in emissions. Estimated maximum 

deposition of Hg to basin 1 of Lake Whatcom was 2.7

(μg/m2)/yr (table 5; fig. 7A), and estimated maximum 

deposition to the three northern lakes was 0.21 (μg/m2)/yr for 

Wiser Lake, 0.31 (μg/m2)/yr for Lake Terrell, and 0.56 

(μg/m2)/yr for Fazon Lake (table 5 and figs. 7A and 7B). 

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 21 
Although regulations allow an operator to assume a rate 

of 54 g/hr for cell-room emissions, modern measurements 

of Hg emission indicate rates between 10 and 20 g/hr. The 

speciation of Hg fugitive emissions from Hg hydrolysis cell 

rooms at two plants (Wangberg and others, 2003; Landis and 

others, 2004) indicate that about 2 percent of the Hg is emitted 

as RGM. Maximum deposition rates of 1.03 (μg/m2)/yr for 

Lake Whatcom were calculated for basin 1 using the short 

residence time and the higher emission rate, with 80 percent 

of the deposition originating from vaporous Hg deposition. 

Because the northern lakes are not in the direction of the 

primary wind pattern for the City of Bellingham, estimated 

maximum deposition was 0.22 (μg/m2)/yr for Fazon Lake.

An understanding of the air chemistry of atmospheric 

emissions from lignin spray dryers is required to predict 

the speciation of the Hg in the hydrogen stream that was 

combusted as a fuel source for the dryers, and to estimate the 

deposition rates to local lakes. The speciation of Hg in the 

combusted hydrogen stream emitted from the lignin spray 

dryers could not be assessed because data on the air chemistry 

of the emissions from the lignin spray dryers are not available. 

The lignin plant did not measure mercury emissions during 

their stack emission test or at any other time during the 

plant’s operation. Only emissions of particulate matter were 

monitored in the gas stream leaving the lignin plant.

The spray dryers at the Bellingham pulp plant were the 

main combustion units, with three or four units operating 

during the nearly 28 years of operation when hydrogen 

was used as the primary fuel source. Natural gas (at least 

10 percent) was used to supplement the hydrogen gas in 

the burner operations. The combustion temperature was 

maintained in the range of 820 to 1,100 oC, at which time 

combustion exhaust gas was mixed with fresh air. This mixture 

entered the spray dryer, where the operating temperature was 

maintained between 230 to 240 oC to assure product quality. 

Hg in the air stream entering the lignin spray dryers after 

combustion of the H2 gas and mixing with ambient air to a 

temperature of 230 to 240 oC likely was in the vaporous phase. 

The calcium- or sodium-based lignin products in liquid form 

were then sprayed into the hot gas stream. The unit used a 

cyclonic flow system in which the lignin was sprayed near the 

top of the cyclone in a manner that is described as spiral flow 

down, such that the dried lignin particles were recovered in 

the lower part of the cyclone. Exit temperatures for gases from 

the spray dryer ranged from 115 and 128 oC. Reduced sulfur 

species from the residual sulfite pulping reagents or chlorine 

from bleaching process that can stabilize the Hg in the RGM 

phase may have been released into the moist air as the lignin 

was dried and the gas stream was cooled to 115-128 oC as it 

left the lignin spray dryer. 

The gases then passed through a multiple-stage cyclone 

where more lignin was recovered. The air exhaust from the 

cyclones was then sent to cold-water scrubbers, most of which 

also had demisters, before being discharged to the atmosphere. 

The particulate concentration of the exhaust typically ranged 

from 20 and 65 milligrams per dry standard cubic meter 

(dscm) and an average particulate-matter emission rate of 

5,200 g/hr for all spray dryers. The burning of H2 gas in lignin 

spray dryers of a Ca-based sulfite mill is a unique operation in 

the U.S. The only two other U.S. Ca-based sulfite mills are in 

Wisconsin. Neither mill complex is associated with a chloralkali plant. Although one Ca-based sulfite mill is associated 

with a lignin spray dryer, emissions data are not available for 

chloride or sulfur species for this lignin spray dryer. 

The only information about the speciation of Hg in 

emissions from combusted hydrogen gas stream is derived 

from a North Carolina Kraft paper mill that burned the 

hydrogen gas stream from the adjacent chlor-alkali plant. 

Within 1 km of a chlor-alkali plant/Kraft pulp mill complex, 

RGM in air associated with the complex accounted for about 

2 percent of the total atmospheric Hg (Hayward and others, 

2003). However, these air mass samples likely contained the 

RGM emitted from the air venting of the mercury cell room 

and the hypochlorite air stream of the chlor-alkali plant. The 

deposition of Hg to local lakes from the hydrogen stream of 

the chlor-alkali plant was not estimated because data are not 

available for the air chemistry of hydrogen streams combusted 

in lignin spray dryers.

Summary of Deposition from Local Air Emissions

The simple model of Hg deposition that was developed 

for this project provides a tool to estimate the relative 

contributions of Hg from the different local emission sources 

to the basins of Lake Whatcom and other lakes in Whatcom 

County. The absolute values of these estimates of deposition 

rates are subject to considerable uncertainty as a result of 

our lack of knowledge of atmospheric residence times of Hg. 

The degree of uncertainty is evaluated by estimating both 

minimum and maximum deposition rates, based on the upper 

and lower bounds, respectively, of the range of residence 

times of the three Hg species reported in the literature. 

The deposition from the hydrogen gas stream could not be 

evaluated because of a complete lack of information on the 

air chemistry of the exhaust gas, and only the maximum 

emissions from the City of Bellingham sewage sludge 

incinerator were estimated because of a lack of speciation and 

air-chemistry data from the stack gas. 

22 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Before the modernization of the Georgia-Pacific chloralkali plant in 1970s, the greatest deposition of Hg from local 

sources [3.75 (μg/m2)/yr] was estimated to have occurred 

within basin 1 of Lake Whatcom because of the prevailing 

wind pattern. Most of the estimated deposition originated from 

RGM emitted from the fume air system of the plant. As the 

chlor-alkali plant was being modernized in 1970s and the fume 

air emissions were virtually eliminated, the maximum estimate 

of the deposition from emissions of the Hg hydrolysis cell 

room of the plant was 1.03 (μg/m2)/yr. At the same time, the 

City of Bellingham sewage sludge incinerator with its simple 

control device [maximum deposition of 1.65 (μg/m2)/yr] and 

the two-unit Thermal Reduction Company, Inc., incinerator 

that violated particulate emissions standards (maximum 

estimate of 1.0 (μg/m2)/yr began operations. The upgrade of 

the Thermal Reduction Company, Inc., incinerator in 1985 

[a decrease in the estimated maximum deposition of Hg to 

basin 1 of Lake Whatcom from 1.0 to 0.77 (μg/m2)/yr] was 

counteracted by the beginning of the operation of the Olivine 

Corp. incinerator [estimated maximum of 1.2 (μg/m2)/yr]. In 

the early 1990s, the upgrades in the pollution-control devices 

in the two municipal incinerators and the municipal sludge 

incinerator led to a chronic reduction of 1.18 (μg/m2)/yr to a 

total maximum deposition of Hg to basin 1 of 2.24 (μg/m2)/yr. 

With the closing of the two municipal incinerators and the 

chlor-alkali plant, the estimated maximum deposition of Hg 

to basin 1 of Lake Whatcom from the City of Bellingham 

incinerator was 0.21 (μg/m2)/yr between 2000 and 2002. 

The lack of speciation data from the oil refinery emissions 

precludes estimating Hg deposition from the two refineries, 

the only other known large facilities emitting Hg. This 

present-day estimate of Hg deposition to basin 1 likely will 

change as better information about the air chemistry of sludge 

incinerators and refineries becomes available. The estimated 

maximum of Hg deposition to the basin 3 sediment coring 

site from Bellingham sources was a factor of 10 less than the 

estimates for the basin 1 site because basin 3 is out of the 

primary wind pattern of the City of Bellingham.

The largest deposition of Hg to lakes in Whatcom 

County from local emission sources was estimated to have 

fallen on lakes north of Bellingham (Lake Terrell, Wiser 

Lake, and Fazon Lake) that are in the primary wind pattern 

of the two municipal waste incinerators. At the time that 

both incinerators were operating with minimal air-pollution 

devices, estimated maximum deposition of Hg to Fazon Lake 

was 11.6 (μg/m2)/yr, and the estimates for Wiser Lake and 

Lake Terrell were 8.38 and 6.15 (μg/m2)/yr, respectively. 

These maximum deposition estimates decreased by 50 percent 

with the addition of dry sorbent air-control devices in the early 

1990s. Deposition from Bellingham sources to these three 

lakes was an order of magnitude less than the deposition from 

the municipal waste incinerators because of the dominant wind 

patterns. 

Wind blows toward Lake Samish from Bellingham 

only under light and variable wind; wind conditions under 

which this model does not simulate Hg deposition well. The 

maximum deposition from 1986 to 1991 was 1.73 (μg/m2)/yr, 

originating primarily from the municipal incinerators. The 

maximum estimate of deposition to Baker Lake from local 

sources from 1984 to 1991 was 0.61 (μg/m2)/yr, but was 

subject to greater uncertainty because of the distance between 

source and target receptor. 

Tributary Riverine Inputs

Ecology (Norton, 2004) collected six water samples 

for the analyses of total Hg from each of three tributaries 

of basin 1 to Lake Whatcom and from seven tributaries to 

basin 3 (fig. 2) from July 2002 to May 2003 (Norton, 2004). 

Total Hg concentrations of individual creek samples ranged 

from the detection limit (<2 ng/L) to 17 ng/L (table 6). 

The concentration of 17 ng/L from Blue Canyon Creek in 

November 2002 was the only concentration that exceeded 

the water-quality standard of 12 ng/L (Norton, 2004). Blue 

Canyon Creek drains a basin containing historical coal mines, 

but the lack of ancillary environmental parameters precludes 

assessing the impact of these mines. 

Median total Hg concentrations for the six measurements 

for each creek ranged from the detection limit for Blue 

Canyon Creek to 5.7 ng/L for Carpenter Creek. Median Hg 

concentrations were 3.8 ng/L in Austin Creek and 3.3 ng/L 

in Anderson Creek. Total Hg concentrations generally were 

higher at the end of the low-flow season, during September 

and November, when specific conductance was higher than 

during the wet season (January and March); this condition 

also was observed in Wisconsin forests (Stoor, 2002). The wet 

season arrived late in 2002 and only one minor precipitation 

event occurred before the November 17 creek sampling (figs. 

8A and 8B). The ratio of average Hg concentrations of dry 

season:wet season ranged from 1.2 for Austin Creek to 2.3 for 

Smith Creek (a comparison was not made for Blue Canyon 

Creek because of the few detectable concentrations). 

For each stream, detectable total Hg concentrations 

were regressed against specific conductance. A significant 

(p <0.05) correlation was observed only for Olsen Creek 

(fig. 9) with higher total Hg and specific conductance being 

observed during the end of the dry season and low detectable 

total Hg concentration observed in March and May (table 6). 

Increased specific conductance in surface waters has been 

attributed to greater ground-water inputs (Winter and others, 

1999). Therefore, the high concentrations of Hg in Olsen 

Creek probably were a result of greater influence of groundwater inputs when ground water contributed most of the base 

flows at the end of the low-flow season. The highest specificconductance values were measured at Silver Beach Creek, 

but total Hg concentrations were not correlated with specific 

conductance.

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 23 
Table 6. Summary of analyses of water samples from the mouth of the tributaries to Lake Whatcom, Washington, July 2002 

to May 2003

[Data from Norton (2004). Location of drainage basins are shown in figure 2. 

ND, not determined; NS, not sampled; <, not detected at detection limit shown. ft3/s, cubic feet per second; 

μS/cm, microsiemens per centimeter at 25oC; mg/L, milligram, per liter; ng/L: nanogram, per liter; –, no data]

Sampling 

round

Collection

date Time Flow (ft3/s)

Specific 

conductance 

(μS/cm)

Total 

suspended 

solids 

(mg/L)

Total 

mercury 

(ng/L)

Total mercury 

(ng/L)

(duplicate)

Anderson Creek

1 07/16/02 8:15 ND 35.2 19 5.5 7.2

2 09/17/02 9:50 6.78 52.7 2 <2 –

3 11/12/02 9:30 31.38 69 7 4.3 –

4 01/07/03 9:25 71.47 38.7 6 4.1 –

5 03/19/03 12:15 69.33 43.4 5 <2 –

6 05/28/03 13:30 62 30 6.5 2.6 2.4

Median............................................................................................. 3.3

Austin Creek

1 07/16/02 9:30 1.19 77.2 1 4 4.5

2 09/17/02 10:40 .67 102.3 <1 3.8 –

3 11/12/02 10:25 2.88 125 2 7.3 –

4 01/07/03 10:15 15.96 46.9 1 3 –

5 03/19/03 11:25 3.24 52.6 3 3.8 –

6 05/28/03 12:40 – 66.5 1 <2 –

Median............................................................................................. 3.8

Brannian Creek

1 07/16/02 8:50 1 37.00 <1 4.5 –

2 09/17/02 10:05 .59 54.6 <1 5.8 –

3 11/12/02 9:50 ND 63.0 <1 9.2 8.8

4 01/07/03 9:45 11 35.6 <1 <2 –

5 03/19/03 11:45 10 37.0 2 4.6 –

6 05/28/03 13:00 1.2 32.9 2 <2 –

Median............................................................................................. 4.5

Carpenter Creek

1 07/16/02 11:30 0.03 100.9 2 7.9 –

4 01/07/03 12:15 3 45.1 <2 7 –

5 03/19/03 9:50 2 49.4 2 4 –

6 05/28/03 9:20 .68 53.1 3 4.4 –

Median............................................................................................. 5.7

Euclid Creek

1 07/16/02 10:08 ND 94.5 2 6.0 –

3 11/12/02 11:00 0.7 90.0 <1 7.4 –

4 01/07/03 10:45 .53 57.4 <1 4.3 –

5 03/19/03 11:00 .34 65.2 3 3.2 –

6 05/28/03 12:00 ND 83.3 3 2.7 –

Median............................................................................................. 4.3

24 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Mill Wheel Creek

4 01/07/03 11:20 1.4 64.6 2 8.9 –

5 03/19/03 10:50 .9 72.8 5 5.1 –

6 05/28/03 11:40 .12 101.4 4 4.9 –

Median............................................................................................. 5.1

Olsen Creek

1 07/16/02 11:40 0.95 73.3 2 6.7 –

2 09/17/02 11:50 .93 102.0 <1 4.9 –

3 11/12/02 12:45 3.1 118.0 7 10 –

4 01/07/03 12:40 9.4 44.4 1 3.8 –

5 03/19/03 9:40 8.3 46.5 2 2.4 –

6 05/28/03 8:55 3.1 51.6 3 2.9 –

Median............................................................................................. 4.4

Silver Beach Creek

1 07/16/02 10:50 0.07 255.0 8 11 –

2 09/17/02 11:20 .09 310.0 5 4.1 3.1

3 11/12/02 12:20 1.1 150 10 11 –

4 01/07/03 11:45 .95 121.8 2 6.4 –

5 03/19/03 10:10 ND 128.4 5 4.4 –

6 05/28/03 9:45 ND 176.0 6 3.1 –

Median............................................................................................. 5.4

Smith Creek

1 07/16/02 12:00 1.61 56.9 1 5.1 –

2 09/17/02 12:20 .79 83.6 <1 4.2 –

3 11/12/02 13:10 11.37 85 4 10 –

4 01/07/03 13:00 12.66 45.2 1 2.6 –

5 03/19/03 9:00 3.05 45.6 2 <2 2.3

6 05/28/03 8:20 ND 47.0 2 2.6 –

Median............................................................................................. 3.4

Blue Canyon Creek

2 09/17/02 9:30 0.79 NS NS <2 –

3 11/12/02 9:10 NS NS NS 17 –

4 01/07/03 9:10 11.4 NS NS <2 <2

5 03/19/03 12:30 12.7 NS NS 4.6 –

6 05/28/03 13:50 3.06 NS NS <2 –

Median............................................................................................. <2

Table 6. Summary of analyses of water samples from the mouth of the tributaries to Lake Whatcom, Washington, July 2002 

to May 2003—Continued

[Data from Norton (2004). Location of drainage basins are shown in figure 2. 

ND, not determined; NS, not sampled; <, not detected at detection limit shown. ft3/s, cubic feet per second; 

μS/cm, microsiemens per centimeter at 25oC; mg/L, milligram, per liter; ng/L: nanogram, per liter; –, no data]

Sampling 

round

Collection

date Time Flow (ft3/s)

Specific 

conductance 

(μS/cm)

Total 

suspended 

solids 

(mg/L)

Total 

mercury 

(ng/L)

Total mercury 

(ng/L)

(duplicate)

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 25 
Total suspended-solids (TSS) concentrations for most 

creeks generally were low, and average TSS concentrations 

from each creek were less than 3 mg/L. However, the TSS 

concentration for Anderson Creek was 19 mg/L during the 

July 2002 sampling, with an average TSS concentration of 

8 mg/L. The average TSS concentration for Silver Beach 

Creek was 6 mg/L, with a maximum of 10 mg/L during the 

November 2002 sampling. Samples for TSS concentrations 

were not collected for Blue Canyon Creek. Because total Hg 

concentrations were not correlated with TSS concentration in 

any creek, particulate Hg concentrations probably were not 

the major fraction of the total Hg during the sampling periods. 

Samples were not collected, however, as the flow of the 

creeks increased after a rainfall event, a time when high TSS 

concentrations are expected. 

Exponent, Inc., an environmental consulting firm, 

collected water samples in October 2001 for analysis of total 

Hg concentrations in four of the creeks that were sampled by 

Ecology (Gary Bigham, Exponent, Inc., written commun., 

2002). Total Hg concentrations ranged from 2.15 to 2.89 ng/L. 

Average concentrations of Hg in samples collected during the 

dry season by Ecology for these creeks ranged from 60 percent 

higher (Anderson Creek) to 130 percent higher (Silver Beach 

Creek) than the average concentrations reported by Exponent, 

Inc. The total methyl-Hg concentrations in two creeks draining 

into basin 1 (Silver Beach and Smith) were about 0.05 ng/L 

and were about 0.13 ng/L for two creeks draining into basin 3 

(Anderson and Austin).

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Figure 8. Daily mean flows of tributaries to Lake Whatcom, Washington, June 2002 – May 2003.

26 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Fine-grained sediment (less than 0.004 mm) containing 

elevated concentrations of Hg (1-8 mg/kg) are known to be 

present in the Middle Fork Nooksack River (Babcock and 

Kolby, 1973; Falley, 1974). The City of Bellingham diverts 

water from the Middle Fork Nooksack River through Mirror 

Lake (fig. 1) and Anderson Creek to Lake Whatcom to 

ensure an adequate drinking-water supply to its residents. In 

October 2001, particulate Hg concentrations of 1.9 ng/L in 

the water entering the terminus of the water diversion system 

(table 7) were calculated using the total and dissolved Hg 

concentrations determined by Exponent, Inc. (Gary Bigham, 

oral commun., 2002) according to:

from the Middle Fork Nooksack River are removed to some 

degree both in a sedimentation pond at the diversion dam as 

well as within Mirror Lake before Anderson Creek flows into 

Lake Whatcom (Tracy, 2001). During the 2002-2003 Ecology 

sampling year, the volume of the Nooksack Diversion was 

28 billion liters (7,404 million gallons), which amounted to 

88 percent of the total flow of Anderson Creek. The total Hg 

concentrations at the terminus of the diversion structure at 

Mirror Lake averaged 3.15 ± 1.34 ng/L (table 7), whereas the 

concentrations of total Hg in Anderson Creek that discharges 

into Lake Whatcom averaged 3.22 ± 2.12 ng/L during periods 

when the diversion was operating (calculated from data in 

table 6). Although the Nooksack Diversion may have supplied 

most of the Hg discharged into Lake Whatcom from Anderson 

Creek from June 2002 to May 2003, the average total Hg 

concentration in Anderson Creek was lower than the average 

for the Lake Whatcom drainage basin. 

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Figure 8.—Continued.

1

(1)

(2)

(3)

(4)

Recoverable Particulate Hg = Total Hg – Dissolved Hg. (5)

Particulate Hg in the Nooksack River water contributes to 

the loading of Hg to Lake Whatcom during periods when this 

water is being diverted. Suspended solids in the diverted water 

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 27 
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Figure 9. Correlation of total mercury and specific conductance in Olsen Creek, 

tributary to Lake Whatcom, Washington.

Table 7. Concentrations of mercury (Hg) at the terminus of the Nooksack River diversion, Whatcom County, 

Washington, October 2001–August 2003

[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25oC; ng/L, nanograms per liter. 

–, no data]

Source/Date

Terminus of Nooksack Diversion (Mirror Lake)

Total 

suspended 

solids (mg/L)

Specific 

conductance 

(μS/cm)

Total Hg 

(ng/L)

Dissolved 

Hg 

(ng/L)

Total 

methyl-Hg 

(ng/L)

Dissolved

methyl-Hg 

(ng/L)

Gary Bigham, Exponent, Inc., written commun., 2002

October 2001 9.2 – 4.81 2.92 0.026 0.026

Peg Wendling, City of Bellingham, oral commun., 2003

August 2002 8.1 66 2.65 – – –

October 2002 – – – – – –

November 2002 3.7 64 2.37 – – –

December 2002 11.0 56 3.35 – – –

January 2003 3.8 50 5.1 – – –

February 2003 – – – – – –

March 2003 2.8 64 1.99 – – –

April 2003 3.2 56 1.76 – – –

June 2003 76.2 46 7.1 – – –

July 2003 72.0 49 7.8 – – –

August 2003 85.0 75 – – – –

 Mean (June 2002 –May 2003) 3.15 – – –

 Standard deviation 1.34 – – –

28 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
The sampling period for which the annual loadings from 

the terminus of the Nooksack Diversion were calculated 

may not have been a representative year. In June 2003, total 

Hg concentrations increased to 7.1 ng/L and remained high 

during the summer of 2003 (7.8 ng/L) (Peg Wendling, City 

of Bellingham, written commun., 2003). TSS concentrations 

of about 80 mg/L were observed during the summer of 2003, 

which were much higher than those for the period used to 

calculate annual loads. These high TSS concentrations in the 

Middle Fork Nooksack River probably were a result of glacial 

melting. If none of Hg was assumed to be in the dissolved 

phase, then the particulate Hg concentration on particles 

would be (7.5 ng/L) / (80 mg/L) or 0.094 ng/mg (or 0.094 

mg/kg). However, about 3 ng/L of Hg was in the dissolved 

phase in October 2001 (Gary Bigham, written commun., 

2002). If only 4.5 ng/L of Hg was in the particulate phase, then 

the Hg concentration on the suspended solids would be 0.05 

mg/kg. Fine-grained particles contain higher concentrations of 

organic matter and more mineral surfaces that adsorb Hg than 

coarse particles. Therefore, the fine-grained sediments that 

settle in the deepest parts of Lake Whatcom due to differential 

settling likely have higher Hg concentration than the estimated 

average concentration of Hg in particles originating from the 

Nooksack Diversion. 

The Park Place settling pond (basin 1) and a street 

drain in Cable Street (basin 2) were sampled to assess the 

input of Hg to Lake Whatcom from stormwater sources. 

The settling pond on Park Place in basin 1 was sampled 

three times. In 1998, water from the settling pond contained 

total Hg concentrations between 8 and 10 ng/L when the 

TSS concentrations were between 18 and 31 mg/L (Serdar 

and others, 1999). Using CVAFS methods, Exponent, Inc. 

(Gary Bigham, written commun., 2002) found total Hg 

concentrations of 1.2 ng/L, of which 0.25 ng/L was methylHg in 2001. Stormwater entering a street drain on Cable 

Street was sampled during two 1998 storm events, and total 

Hg concentrations were about 6 ng/L, even though the TSS 

concentrations were as high as 220 mg/L. During a different 

sampling trip, suspended matter in water entering the Cable 

Street drain was collected using a sediment trap and the Hg 

concentration on the suspended matter was 0.062 mg/kg.

The loading of Hg (mass/time) can be calculated by 

multiplying the Hg concentration (mass/volume) times the 

flow rate (volume/time). The calculations of Hg loadings are 

based on the average Hg concentrations from the wet season 

(December 2002 to April 2003) and the dry season (June to 

November 2002 and May 2003) because of the limited set 

of Hg data. The flow data were obtained from Institute of 

Watershed Studies of the Western Washington University 

(Anderson, Austin, and Smith Creeks) and the USGS (Silver 

Beach, Euclid, Mill Wheel, Brannian, Carpenter, and Olsen 

Creeks). The methods for estimating missing flow data 

are explained in appendix C. The total annual volumes of 

water are shown in table 8. The flow of Anderson Creek is 

anomalous in that the dry-season flow is higher than the wetseason flow because of the addition of water diverted from the 

Nooksack Diversion during the dry season. 

The loadings of Hg were roughly proportional to the 

total annual water volumes of each creek. Anderson Creek 

contributed 98.6 g of Hg to Lake Whatcom from June 2002 to 

May 2003. Using the average Hg concentration at the terminus 

of the Nooksack Diversion system, 88 ± 37 g of the 98 g of 

Hg was attributed to the flow of the Nooksack Diversion. In 

contrast, the low-flow Brannian Creek annually contributed 

only 0.8 g of Hg to Lake Whatcom. 

Likewise, TSS concentrations were averaged over the 

year by season, and the seasonal TSS averages were multiplied 

by the total seasonal flows to obtain an estimate of the annual 

TSS loadings that are representative of the sampling period 

(June 2002-May 2003). By this calculation, Anderson Creek 

contributes 230 Mg of sediment of the estimated 272 Mg 

loading to Lake Whatcom. Using monthly averages of the TSS 

and the monthly diversion volume, the Nooksack diversion 

contributed 153 Mg to the TSS loading of Anderson Creek. 

However, the 272 Mg annual loading estimate may have 

been on the lower end of the range of TSS annual loading. 

In the summer of 2002, the average TSS concentration for 

the Nooksack Diversion was 8 mg/L, and the average for the 

summer of 2003 was about 80 mg/L. If the year on which the 

annual TSS loading was calculated was shifted forward by 

3 months to include the summer of 2003 (September 2002–

August 2003), the TSS loading of the Nooksack Diversion 

would nearly double from 153 to 293 Mg. 

Table 8. Annual loadings of mercury (Hg) to Lake Whatcom, 

Washington, from tributary inflows, June 2002 – May 2003

[A megagram is 106 grams, which is commonly known as a metric ton]

Tributaries Water 

(liters × 109)

Hg 

(grams)

Total 

suspended 

solids

(megagrams)

Anderson 31.76 98.6 230

Austin 8.58 30.0 16.3

Olsen 4.78 17.4 8.9

Smith 5.64 16.1 8.7

Carpenter 1.33 7.4 2.4

Mill Wheel .52 3.6 2.1

Silver Beach .59 3.3 1.8

Euclid .27 1.1 .5

Brannian .27 .8 .4

 Total 178.5 272

Evaluation of Possible Sources of Mercury to Lake Whatcom and Other Lakes in Whatcom County 29 
The Nooksack Diversion clearly has a significant impact 

on the loadings of Hg and TSS to Lake Whatcom. However, 

this impact is due primarily to the large volume of water 

flowing through the diversion relative to the natural flow 

of Anderson Creek rather than to the Hg concentration in 

the water or on the particles being transported through the 

Nooksack Diversion. In fact, the total Hg concentration of the 

Nooksack Diversion is less than the average for the tributaries 

of Lake Whatcom. 

Ground-Water Sources

Assessments of Hg inputs from ground water to lakes in 

Whatcom County require knowledge of both the concentration 

of Hg in ground water and the flow rates of direct discharge 

of ground water to the lakes. Ground-water models that would 

provide estimates of freshwater inputs from direct groundwater discharges have not been developed for the area. In 

addition, sensitive high-quality measurements of Hg in ground 

water have not been made for the drainage basins of the lakes. 

Hg present in ground water could originate from 

Hg in precipitation, from desorption of Hg, from natural 

aquifer materials, or from human inputs. Anthropogenic 

inputs include releases of leachate solutions from regulated 

and unregulated solid-waste facilities, and releases from 

septic systems. Two municipal solid-waste sites have been 

investigated using low-sensitivity screening methods with 

detection limits ranging from 100 to 500 ng/L for the analysis 

of Hg (BEK Engineering & Environmental, Inc., 2002a). 

Total Hg concentration of one of two samples of shallow 

ground water collected within the confines of the Y-road 

Landfill I (fig. 6) was 300 ng/L. The total suspended-solid 

concentration in this sample was 1,300 mg/L, indicating that 

much of the total Hg in this sample may have been associated 

with the particles. The dissolved Hg concentrations for these 

two ground-water samples were less than the detection limit 

of 100 ng/L. Hg concentrations in samples from five private 

wells within 608 m of the landfills were less than the detection 

limit of 100 ng/L. Dr. Susan Cook (Toledo, Washington, 

written commun., 2003) collected a water sample originating 

from a domestic well within 608 m of the landfill in 1990 

and reported an Hg concentration of 220 ng/L using a more 

sensitive ICP-MS method. The concentrations of total iron 

(Fe) and aluminum (Al) in this sample were low, indicating 

that the sample contained few suspended-sediment particles. 

Although the ICP-MS provided a more sensitive analyses 

for Hg, the lack of quality-control data for the samples 

precluded an assessment of any contamination from the well 

structures and sampling procedures. Water pumped from 

wells and stored in the holding tank of the Y-Squalicum Water 

Association that was provided to Dr. Cook by the Association 

contained 90 ng/L of total Hg. However, this sample contained 

11 mg/L of total Fe and 0.3 mg/L of total Al, indicating the 

presence of a significant amount of suspended sediments. 

Wood-yard waste from the Georgia-Pacific pulp mill was 

deposited in the Lake Whatcom drainage basin on a lot located 

on the 3200 block of Britton Road (fig. 6). Hg concentrations 

in soils on the site were less than 0.05 mg/kg, whereas Hg 

concentrations in ground water collected from the site were 

less than the detection limit of 500 ng/L (Melinda Miller, 

Whatcom County Department of Health, oral commun., 2003).

Two other sites containing wood waste from GeorgiaPacific outside of the Lake Whatcom drainage basin have been 

studied more extensively, and Hg concentrations in ground 

water are presented here as examples of the water quality 

surrounding wood-waste sites. At the Hilltop Woodwaste 

Landfill, Hg concentrations in soil were greater than the 

method detection limit (MDL) in three of seven soil samples, 

with a maximum concentration of 0.7 mg/kg. Total Hg was 

not detected at 11 of the 21 ground-water sampling sites at 

concentrations significantly greater than the detection limits 

for analyses in which the detection limit ranged from 100 to 

1,000 ng/L (BEK Engineering & Environmental, Inc., 2002b). 

Total Hg concentrations were greater than the MDL of 200 

ng/L in 11 samples collected at the other 10 sites. However, 

total Fe concentrations were greater than 10 mg/L in 9 of these 

11 samples, which indicates possible particulate contamination 

of the ground water. The average total Hg concentration 

for the two samples that had detectable Hg with total Fe 

concentrations less than 1.0 mg/L was 400 ng/L (MDL = 100 

ng/L). Total Hg was detected in 1 of 38 samples that were 

analyzed with a resulting detection limit of 200 ng/L; however, 

this one sample also had a total Fe concentration of 3.3 mg/L. 

30 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
The landfill containing Georgia-Pacific wood waste 

located at the Bellingham Airport (fig. 6) also was investigated 

(BEK Engineering & Environmental, Inc., 2002c). Hg 

concentrations in most of the ground-water samples were less 

than or near the detection limits (detection limit for analyses 

ranged from 200 to 1,000 ng/L). One of the four samples 

with Hg concentrations greater than the detection limit of 

200 ng/L also had a high Fe concentration. The average Hg 

concentration of the three other samples was 300 ng/L. 

The release of Hg from septic systems surrounding the 

lakes of Whatcom County could not be assessed because 

of a lack of local or regional data. Very little is known 

about the concentrations and sources of Hg discharged 

from domestic sewage sources. The mean concentration of 

Hg in wastewater collected by publicly owned treatment 

works servicing residential areas was 138 ng/L, with TSS 

concentrations ranging from 39 to 245 mg/L for one set of 

residential areas (Association of Metropolitan Sewerage 

Agencies, 2000). Although many household products contain 

low concentrations of Hg, the major source of Hg in domestic 

wastewater was thought to be excretion of Hg released into the 

body from dental fillings. Skare (1995) suggests that 25 mg of 

Hg per year is excreted by people with a moderate amount of 

dental fillings, of which 1.6 mg of Hg per year is excreted in 

urine. If septic tanks were totally efficient in trapping the fecal 

and other solid materials, 1 g of Hg would be released into 

ground water for each 600 people having a moderate number 

of dental fillings and living in houses served by septic systems 

surrounding the lake. If colloidal material containing Hg 

escaped the septic tank and was released into the drain field, 

the number of people with fillings served by septic systems 

required to release 1 g of Hg into the ground water would be 

less. In the reducing condition of a septic tank, geochemical 

principles suggest that methylation of Hg would likely occur 

and some of the Hg released into the ground water from a 

functioning septic system would be in the form of methylHg. About 30 percent of the Hg in the surface discharge 

from a failing septic system was in the methyl-Hg form (Dr. 

Susan Cook, written commun., 2003.) Once discharged to the 

ground-water system, the Hg could be adsorbed by aquifer 

materials, enter the lake, or bypass the lake, depending on the 

ground-water flow path. 

Mercury in Lake Whatcom and Other 

Lakes in Whatcom County

Sediments

Surface Sediments

As part of the companion study, Ecology (Norton, 2004) 

collected five random surface-sediment samples (0 to 2 cm) 

in Lake Whatcom basins 1 and 2, and 11 random samples 

from basin 3 in September 2002. Targeted samples within 

the deltas of tributaries were collected in basin 1 (n = 3) and 

basin 3 (n = 7). All surface-sediment samples were analyzed 

for grain size, total organic carbon (TOC), and total mercury 

by cold-vapor atomic absorption spectrometry (CVAAS). In 

addition, all random samples from basins 1 and 2 and one-half 

of the random samples from basin 3 were analyzed for methylHg. The mean Hg concentration of the 31 samples was 0.14 

mg/kg (ranging from 0.014 to 0.22 mg/kg). The Washington 

State Freshwater Sediment Quality Values (FSQV) are being 

updated, and Norton (2004) compared the Hg concentrations 

in Lake Whatcom with other FSQVs. Norton (2004) reported 

that no surface sediment samples exceeded Environment 

Canada’s Probable Effects Level of 0.49 mg of Hg per 

kilogram. Adverse biological effects frequently occur 

at concentrations greater than the Environment Canada’ 

threshold effects level (TEL) of 0.17 mg/kg and adverse 

biological effects rarely occur at concentrations less than the 

TEL. Hg concentrations in 36 percent of the surface-sediment 

samples exceeded the TEL.

The delta of the tributaries contained coarser grained 

sediments than the random samples from the respective 

basins (fig. 10). Concentrations of total organic carbon 

generally were higher in basin 1 than basin 2, with basin 

3 having the least TOC. Relations between TOC and 

percentage of sediment in the finest clay fraction (less than 

0.004 mm) were not significant. An attempt was made to 

identify biogeochemical processes that result in higher Hg 

concentrations in the sediments. A strong linear correlation 

(r2 = 0. 78, p <0.01) between total Hg and TOC was found for 

the subset set of samples containing basin 3 tributary samples, 

and a weaker correlation was found for the entire data set 

(r2 = 0.22, p <0.01). In contrast, a relation for the entire data 

set that seemed to be non-linear was observed between total 

Hg and the percentage of fine sediment, with total Hg in two 

samples significantly less than the pattern would indicate 

(fig. 10). Methyl-Hg was not linearly correlated with 

percentage of fines (r2 = 0.13, p =0.17), but was highly 

linearly correlated with TOC (r2 = 0. 80, p <0.01). Because 

TOC concentrations were highest in basin 1 sediments, 

concentrations of methyl-Hg also were highest in basin 1 

sediments (fig. 11).

Mercury in Lake Whatcom and Other Lakes in Whatcom County 31 
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Figure 10. Relation of total organic carbon and total mercury to percentage of fines (<0.004 mm) in samples of surface 

sediments collected in 2002 near tributaries and in the three basins of Lake Whatcom, Washington.

Data are from Norton (2004). The two outlying samples are labeled with the site No.

32 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Mercury Sedimentation in Lakes

Hg sedimentation rates were derived from sediment 

cores from the lakes in Whatcom County. Cores from Lake 

Whatcom are described in Norton (2004) and sediment cores 

from Lake Samish, Lake Terrell, Fazon Lake, Wiser Lake, 

and Baker Lake are described in appendix D (table D1). The 

method for deriving mass sedimentation rates from the stable 

lead (Pb), radioactive Pb (210Pb), and radioactive cesium 

(137Cs) data (table D2) are described in appendix D, along with 

the derived sedimentation rates for the eight cores 

(table D3). 

Calculations based on a constant sedimentation rate for 

each core generally provided consistent sedimentation rates 

within the error of each measurement (about 50 percent). 

Four of the cores exhibited peaks in 137Cs at a consistent 

peak concentration of about 3 pCi/g (table 9). The 137Cs peak 

of 0.97 pCi/g for the core from basin 3 of Lake Whatcom 

was disregarded because the analytical signal was weak 

compared to the peak for other cores. The recent deposition 

of 210Pb also was consistent among the lakes [0.3 to 0.7 

(pCi/cm2)/yr]. The higher deposition of 210Pb in Baker Lake 

probably was a result of the much higher suspended-matter 

input from its much larger drainage basin. The total organic 

carbon data in the surface sediments also are given in table 9. 

TOC concentrations were highest in the three northern lakes, 

ranging from 18.0 to 25.5 percent. These three smaller lakes 

have only intermittent freshwater flows and are considered 

catchment lakes. The three larger lakes (Lake Whatcom, 

Lake Samish, and Baker Lake) have much lower surface TOC 

concentrations, with Baker Lake having the lowest surface 

concentrations. Within Lake Whatcom, the concentration 

of TOC in the top section of these cores follows the same 

decreasing trend in TOC from basin 1 to basin 3 that was 

observed with the surface sediments (Norton, 2004). Peak and 

historical Pb concentrations are given to provide insight into 

the overall contamination of the site from atmospheric sources 

(table 9). The surface, peak, and historical concentrations of 

Hg and Hg sedimentation rates also are given. 

Linear sedimentation rates (cm/yr) can be calculated 

given the constant mass-sedimentation rate [g/cm2)/yr] 

and the porosity (measure of water content) of the surface 

sediments (see appendix D). The surface linear-sedimentation 

rate ranged from 0.20 cm/yr for basin 3 of Lake Whatcom to 

0.99 cm/yr for Baker Lake. The inverse of the surface linearsedimentation rate provides a measure of the number of years 

of sedimentation that the top 1-cm section represents. Thus, 

the top 1 cm of the core from basin 3 of Lake Whatcom 

represents 5 years, whereas the top 1 cm of the core from 

Baker Lake represents 1 year.

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Figure 11. Relation of methyl-mercury to total organic carbon in samples of surface sediments from the three 

basins of Lake Whatcom, Washington, 2002. 

Data are from Norton (2004). 

Mercury in Lake Whatcom and Other Lakes in Whatcom County 33 
Table 9. Summary of concentrations and sedimentation rates of mass, total organic carbon, mercury (Hg), lead, lead-210, cesium-137, 

and total organic carbon in sediment cores from lakes in Whatcom County, Washington

[Mass sedimentation rate: Bold number indicates high confidence in the value (see appendix D); Italicized number indicates a moderate confidence, and an 

underlined number indicates a low confidence. pCi/g, picocurie per gram; mg/kg, milligrams per kilograms; g, grams; cm, centimeters; mg, milligrams; 

pCi, picocuries; cm2/yr, square centimeters per year; (mg/cm2)/yr, milligrams per square centimeter per year. –, not calculated because of insufficient data]

Lake

Surface concentration Peak concentration

Porosity

Total organic

carbon

(percent)

Lead-210

(pCi/g)

Hg

(mg/kg)

Lead

(mg/kg)

Cesium-137

(pCi/g)

Hg 

(mg/kg)

Whatcom Lake

Basin 1 0.944 9.2 8.9 0.229 95 3.78 0.259

Basin 2 .937 5.2 7.8 .202 48 3.13 .204

Basin 3 .927 4.3 8.5 .204 14.4 .97 .217

Lake Samish .943 5.7 10 .130 63 – .19

Fazon Lake .972 25.5 113.4 .180 88 3.33 .27

Lake Terrell .965 19.4 13 .160 91 3.23 .22

Wiser Lake .956 18.0 6.5 .230 68 – .403

Baker Lake .862 2.5 3.1 .056 43 5.03 .166

Historical concentration Sedimentation

Recent Hg [(ng/cm)2/yr]

Lake Porosity Lead

(mg/kg)

Hg

(mg/kg)

Mass

[(g/cm2)/yr]

Linear

(cm/yr)

Total organic 

carbon

[(mg/cm2)/yr]

Lead-210

[(pCi/cm2)/yr] Recent Peak Historical

Whatcom Lake

Basin 1 0.928 4.6 0.086 0.045 0.30 4.1 0.40 10.3 11.7 3.9

Basin 2 .897 5.0 .082 .040 .24 2.1 .31 8.1 8.2 3.3

Basin 3 .693 10.0 .085 .040 .20 1.7 .34 8.2 8.7 3.4

Lake Samish .916 6.1 .088 .072 .47 4.1 .72 9.4 13.7 6.3

Fazon Lake .969 13.3 .14 .039 .52 9.9 1.52 7.0 10.5 5.5

Lake Terrell .927 6.6 .079 .031 .33 6.0 .40 5.0 6.8 2.4

Wiser Lake .953 2.6 .23 .049 .41 8.8 .34 11.3 19.7 –

Baker Lake .749 27.3 – .370 .99 9.3 1.15 20.7 61.4 –

1

Estimated from subsurface samples.

34 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
The average time before the core collection date of 2002 

that a specific core section was deposited within the sediment 

column was estimated by dividing the cumulative mass 

sedimentation at the mid-point of the section by the assigned 

mass sedimentation rate (table 9). Likewise, the time interval 

over which the core section was deposited was estimated by 

dividing the cumulative mass sedimentation at the top and 

bottom of the core section by the assigned mass sedimentation 

rate. Having transformed the depths (table 10) to their dates of 

deposition, the trend in Hg sedimentation in each core section 

was examined back in time by dividing the Hg concentration 

in each section by the historical background concentrations 

observed within the deepest sections of that core (fig. 12). The 

resulting ratio is called an “enrichment ratio” and accounts for 

the different sediment types that accumulate Hg at a specific 

location as a result of differences in grain size or organic 

content. This treatment of the Hg data with depth in the core 

facilitates the comparisons among lakes. The sedimentation 

rates are subject to uncertainties described in appendix D. 

The histories of Hg inputs to the lakes of Whatcom 

County are recorded in the sediments of each lake. Prior 

to 1910, Hg concentrations in sediments from the cores in 

basins 1 and 2 of Lake Whatcom were fairly constant back 

to the early 1800s (enrichment ratio about 1 in fig. 12A). The 

average background concentrations were 0.086 and 0.095 

mg/kg, respectively (Norton, 2004). In the core from basin 3 

of Lake Whatcom, Hg concentrations ranged from 0.055 to 

0.113 mg/kg for the period between about 1590 (30 cm) and 

1925 (7 cm), corresponding to Hg enrichment ratio between 

0.65 and 1.17. After 1910, enrichment ratios increased rapidly 

in all three basins. In basin 1, the enrichment ratios increased 

to 2.34 in 1953 (±5 years) before increasing more slowly 

between 1953 and 1996, at which time a maximum enrichment 

ratio of 2.95 was observed. In basin 2, the enrichment ratio 

reached 2.04 in 1975 and only increased to 2.15 by 1995. The 

maximum enrichment ratio for basin 3 (2.55) was found in 

1958 (±6.6 years) in the 4-5 cm section, before decreasing 

slightly to 2.4 in the surface 2 cm (1988–2002). Hg appears to 

be decreasing in sediments recently deposited in basin 1.

The history of Hg deposition to the basins of Lake 

Whatcom are examined in relation to the human development 

of the drainage basin and the City of Bellingham. The preindustrial sedimentation of Hg in cores from the deepest parts 

of each basin ranged from 3.4 to 3.9 (ng/cm2)/yr (fig. 13). 

Most of the increases in Hg sedimentation in Lake Whatcom 

and the five other lakes occurred before major facilities 

emitting Hg to the atmosphere began operating in Whatcom 

County. This observation suggests that the general global 

air pollution resulting from the Industrial Revolution during 

the first one-half of the 20th century was responsible for a 

significant amount of Hg loading to Lake Whatcom. For basin 

3 of Lake Whatcom, the sedimentation between 1952 and 

1965 represents the peak rate of sedimentation of Hg. For 

basins 1 and 2, the sedimentation of Hg immediately prior 

to the onset of major local emissions sources represents 80 

percent of the peak sedimentation for sediments deposited 

in the 1990s (fig. 13). The small increases in Hg in basins 

1 and 2 after 1964 could have been a result of either further 

increases in deposition from global sources, the Hg emissions 

of the Bellingham chlor-alkali plant, and the municipal waste 

incinerators near Bellingham, or increased tributary loadings 

to the lake from the Nooksack Diversion. The fact that the 

enrichments in Hg after 1964 among the basins of Lake 

Whatcom do not correlate with the estimated atmospheric 

deposition from local atmospheric Hg sources indicates that 

local atmospheric Hg emissions were not the dominant sources 

of Hg to the lake. The small decrease in the Hg concentrations 

in the most recently deposited sediment to basin 1 (fig. 13) 

might possibly have been the result of the closing of the two 

incinerators in 1997. The concentration of Hg in the top 1-cm 

section of the core basin 1, which represents 3-4 years of 

sedimentation, would unlikely have had time to respond to 

the closing of the chlor-alkali plant just two years prior to the 

collection of the core.

From 1890, when Hg concentrations were 0.088 

mg/kg, Hg enrichment ratio (fig. 12B) of the Lake Samish 

core increased erratically to a value of 1.6 in 1954 (±5 years). 

Between 1975 and 1998, the enrichment ratio averaged about 

2.0. Hg enrichment was observed as early as 1920 in the 

Fazon Lake core, and an enrichment ratio of 1.86 was found 

for the section dated 1950 (±4 years). Between 1950 and 

1998, enrichment ratios ranged from 1.64 to 1.93. Significant 

decreases in enrichment ratios were observed for recently 

deposited sediments in both Samish Lake and Fazon Lake.

The enrichment ratio for Terrell Lake sediments increased 

to 1.2 by 1920 and increased to 2.8 in 1958 (fig. 12B). 

Between 1968 and 1989, the enrichment ratio was fairly 

constant, at a lower value of about 2.6. The enrichment ratio 

for sediments deposited within the last 8 years was near 2.0. 

The Wiser Lake core appeared to show numerous 

disturbances (table D1), including numerous dramatic shifts 

in the subsurface distribution of Hg (table 10), making 

interpretation difficult. Enrichments for Baker Lake could not 

be calculated because the bottom of the core did not reach a 

depth that represented dates prior to global industrialization. 

Hg concentrations decreased from 0.121 mg/kg in 1967 to 

0.056 mg/kg after 2000, except for a peak of 0.166 mg/kg 

in 1977. The peak possibly was a result of adsorption of Hg 

released from soils covered with water during the filling of 

Baker Lake as it was expanded to a reservoir in the early 

1960s. Hg releases from unsaturated soils have been observed 

after filling of other reservoirs (Therriault and Schneider, 

1998). The fairly gradual decrease in Hg in the core from 

Baker Lake might reflect either the trend in global deposition 

or a time lag of 1960s atmospheric Hg deposition reaching the 

core location as a result of focusing within the reservoir after 

its filling.

Mercury in Lake Whatcom and Other Lakes in Whatcom County 35 
Location Collection 

date

Depth

interval 

(cm)

Total mercury 

(mg/kg, dw)

Lake Samish 09/23/02 0-1 0.13

1-2 .19

3-5 .166

6-8 .178

9-11 .142

12-14 .112

15-17 .161

18-20 .12

22-24 .11

27-31 .088

Fazon Lake 09/24/02 0-1 .18J

1-2 .27J

3-5 .26J

7-9 .26J

11-13 .23J

15-18 .24J

21-24 .26J

27-30 .22J

33-36 .21J

40-44 .14J

Lake Terrell 09/23/02 0-1 .16J

1-2 .15J

3-5 .2J

5-7 .21J

7-9 .21J

9-11 .2J

12-14 .22J

15-17 .14J

18-21 .095

23-25 .079J

Table 10. Summary of analyses of mercury (Hg) in sediment cores from lakes in Whatcom County, Washington, September 2002

[Total mercury: J, estimated value because holding time elapsed. cm, centimeter; mg/kg, dw, milligrams per kilograms in dry weight]

Location Collection 

date

Depth

interval 

(cm)

Total mercury 

(mg/kg, dw)

Wiser Lake 09/24/02 0-1 0.23J

1-2 .16J

3-5 .403J

7-9 .13J

11-13 .16J

14-16 .372J

20-23 .14J

26-29 .33J

32-35 .367J

40-44 .23J

Baker Lake 09/26/02 0-1 .056

1-2 .057

3-5 .065

6-8 .0728

9-11 .0762

12-14 .0636

15-17 .166

18-20 .105

21-23 .121J

25-27 .1 

36 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure 12. Relation of enrichment ratio of mercury with time in sediment cores from the three basins of Lake Whatcom, 

and Lake Terrell and Fazon and Wiser Lakes, Whatcom County, Washington, 2002.

Mercury in Lake Whatcom and Other Lakes in Whatcom County 37 
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Figure 12.—Continued.

38 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
 The enrichment ratios for the cores from basin 2 of Lake 

Whatcom, Lake Samish, and Fazon Lake reached a maximum 

of about 2 in the 1980s. These values are low compared to 

enrichment ratios as high as 6 in Midwest lakes (Benoit and 

others, 1994). The core from Lake Samish exhibited decreases 

in Hg concentrations in the 1-cm section, which represents 

2 years (linear sedimentation rate of about 0.5 cm/yr). In 

contrast, no decrease was observed in the top 1-cm section 

of the core from basin 2 of Lake Whatcom, which represents 

4 years. Basin 2 of Lake Whatcom, Lake Samish, and Fazon 

Lake have little or no channelized surface water inflow. Basin 

2 of Lake Whatcom receives very little surface water inflow 

from creeks, and Fazon Lake is a catchment basin. Although 

Lake Samish receives some water from a small creek, the 

flows from the outflow creek were always greater than surface 

inflows. 

If local atmospheric inputs were a major source of Hg to 

the lakes, a general relation between the estimated atmospheric 

deposition from local emission sources and increases in 

enrichment would be expected. The sum of the estimated peak 

Hg deposition from atmospheric local sources in the mid1980s, primarily from incinerators, amounted to 7 percent 

of the peak sedimentation of Hg of Fazon Lake. In contrast, 

the sum of the estimated peak Hg deposition from local 

atmospheric sources to Lake Samish was equal to 1.6 percent 

of peak Hg sedimentation. Even if the value of the estimated 

Hg atmospheric deposition were low because of uncertainty 

in atmospheric residence of Hg species, the enrichment ratio 

for Fazon Lake would be expected to be much higher than 

those of Samish Lake if deposition from local Hg sources 

was the primary source of Hg. Yet, the enrichment ratios for 

Fazon Lake and Lake Samish were similar. The decrease in 

Hg emissions over time because of improvements in local airpollution control devices also are not reflected in decreases in 

enrichment ratios in the 1980 and 1990s. 

Mercury enrichment ratios were from 2.5 to 3.0 for 

basins 1 and 3 of Lake Whatcom, which receive significant 

amounts of surface waters. The maximum enrichment 

ratios for Lake Terrell also were near 3. The timing of the 

enrichment plateau in Lake Terrell between 1960 and 1990, 

however, was unique among the lakes that were studied and 

did not seem to coincide with changes in local emission rates, 

which indicates a source within the drainage basin. The higher 

enrichment ratios of basins 1 and 3 of Lake Whatcom, and 

Lake Terrell, probably are related to the inflow of suspended 

sediments from their respective drainage basins.

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Figure 13. Historical, pre-1964, peak and recent rates of mercury 

accumulation in core sections from Lake Whatcom, Washington. 

The dates when the core section was deposited (on the x-axis) were 

estimated from the mass accumulation rate and the thickness of the core 

section. Pre-1964 rates of mercury accumulation predate the operation 

of first major Hg emission source.

Mercury in Lake Whatcom and Other Lakes in Whatcom County 39 
Water Column

On October 11, 2001, seven water samples (table 11) 

were collected by Exponent, Inc. (Gary Bigham, written 

commun., 2002) from Lake Whatcom using ultra-clean 

techniques, and the samples were analyzed for Hg and methylHg using the most sensitive CVAFS technique available. 

Samples were collected from the surface layer (epilimnion) of 

each basin and near the bottom layer of basins 1 and 2. 

In the surface layer of all three basins, total Hg 

concentrations ranged from 0.37 to 0.61 ng/L, with the 

highest surface concentration in the sample from basin 3 

(table 11). Dissolved Hg concentrations ranged from 0.29 to 

0.66 ng/L, with the highest concentration in the sample from 

basin 1 (fig. 14). Dissolved methyl-Hg concentrations in the 

epilimnion were less than or near the detection limit of 0.020 

ng/L in all three basins. Total methyl-Hg concentrations were 

detectable, indicating that methyl-Hg on particles represents 

between 39 percent and greater than 50 percent of the total 

methyl-Hg in the epilimnion of basins 1 and 2, respectively. 

The concentrations and biogeochemistry of Hg in the two 

samples from basin 3 within (23 m) and just below (30 m) the 

mixed layer resembled those of epilimnion samples, probably 

because these samples were collected at least 67 m above the 

bottom.

The only quality-assurance discrepancy for this data 

set was the fact that the concentration of dissolved Hg for 

basin 1 (0.66 ng/L) was higher than total Hg (0.51 ng/L). 

Particulate Hg concentrations estimated from equation 5 have 

large uncertainties because they usually are based on small 

differences between two large numbers, each with relative 

standard deviations of 10 percent or more. Given these 

unknown uncertainties, the particulate Hg concentrations 

in the epilimnion were estimated to be 0.08 ng/L for basin 

2 and 0.23 ng/L for basin 3. Recoverable particulate Hg 

in the epilimnion of basin 2 and 3 represented 22 and 38 

percent, respectively, of the total Hg. Although particulate Hg 

concentrations on the suspended particles are more accurately 

determined by direct analysis of particles, these data can be 

used to estimate particulate concentrations by the equation:

from 0.08 to greater than 0.46 mg/kg, which were higher 

than Hg concentrations of the randomly collected surface 

sediments, which ranged from 0.014 to 0.23 mg/kg. Although 

the dissolved Hg concentration in the 5-MAB sample from 

basin 1 (0.54 ng/L) was similar to those in the epilimnion, the 

dissolved Hg concentration of the 2-MAB sample from basin 

2 (1.4 ng/L) was much higher than that of any other sample. 

The most significant result was the much higher portion 

of the dissolved Hg found as methyl-Hg in near-bottom waters 

(fig. 14B). Dissolved methyl-mercury concentrations in nearbottom samples were from 5 to 50 times higher than those 

in the epilimnion and constituted 64 and 95 percent of the 

dissolved Hg in basins 1 and 2, respectively. In October 2001, 

dissolved oxygen was depleted at depths below 12 and 15 m 

in basins 1 and 2, respectively (Mathews and others, 2003). 

In 2001, hydrogen sulfide (H2S) was present in the bottom 

waters of basins 1 and 2, indicating that sulfate reduction was 

occurring. Maximum rates of methyl-Hg production have been 

shown to occur under reducing conditions when the sulfate 

reduction rates are low (1-8 nanomoles cm2/d) (MarvinDiPasquale and Agee, 2003). 

Calculated particulate methyl-Hg concentrations in nearbottom samples in basins 1 and 2 (0.03 and 0.11 mg/kg) were 

higher than those in the epilimnion (0.016 mg/kg) and an order 

of magnitude higher than methyl-Hg concentrations in the 

sediments of basins 1 and 2. 

The City of Bellingham (William McCourt, written 

commun., 2003) collected monthly water samples for Hg 

analysis by CVAFS at the intake gatehouse at the shore end 

of the wood-stave intake pipe extending about 366 m into 

Lake Whatcom for drinking-water withdrawals beginning 

in November 2002. The concentration of total Hg in six of 

the eight samples ranged from 0.69 to 0.89 ng/L, and the 

concentration in two samples was 1.7 ng/L (table 12). These 

values are within the general range of total Hg concentrations 

in basin 2 of Lake Whatcom observed by Exponent, Inc. 

In comparison, the Maximum Contaminant Levels for total 

mercury in drinking water are 2,000 ng/L (U.S. Environmental 

Protection Agency, 2002; 2004). 

Fish

Four studies have investigated Hg concentrations in 

largemouth bass, smallmouth bass, cutthroat trout, yellow 

perch, and brown bullhead in lakes in Whatcom County 

(Serdar and others, 1999, 2001; Seiders, 2003; and this 

study). The slow elimination of Hg from freshwater game 

fish results in the accumulation of Hg with age, weight, and 

length in these fish (Munn and Short, 1997; Gilmour and 

Riedel, 2000; Serdar and others, 2001). Hg concentrations for 

specific fish species are examined to determine differences 

among lakes and among basins within Lake Whatcom that 

take into consideration the differences in the length of the 

fish specimens analyzed. The bioaccumulation of Hg in the 

trophic levels of the food web of Lake Whatcom have been 

summarized in Mueller and Serdar (2002).

These calculations result in particulate concentrations ranging 

from 0.10 to greater than 0.46 mg/kg. 

The biogeochemistry of Hg of the near-bottom water 

samples from 5 meters above bottom (MAB) in basin 1 and 2 

MAB in basin 2 was significantly different than those in the 

epilimnion. Total Hg concentrations were higher than those 

in the epilimnion in near-bottom samples, partly because of 

higher TSS concentrations (2.8 to 6.4 mg/L) in the epilimnion. 

Recoverable particulate Hg concentrations were 0.52 and 1.16 

ng/L, respectively, and constituted about 45 percent of the total 

Hg. The estimated Hg concentrations on the particles ranged 

1

(1)

(2)

(3)

(4)

(5)

Particulate Hg (mg/kg = ng/mg) = 

Particulate Hg (ng/L)/ TSS (mg/L). (6)

40 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Table 11. Concentrations of total and dissolved mercury (Hg) and methyl-mercury in Lake Whatcom, Washington, October 2001

[Reported concentrations: Data from Gary Bigham, Exponent, Inc., written commun., 2002. m, meters; ng/L, nanograms per liter; 

mg/kg, milligrams per kilogram. >, actual value is greater than value shown; <, not detected at the detection limit shown; NA, not applicable]

Water body Latitude Longitude Sample ID. Depth

(m)

Meters 

above 

bottom

(m)

Reported concentrations

Total 

suspended 

solids

(mg/L)

Hg (ng/L) Methyl-Hg (ng/L)

Total Dissolved Total Dissolved

Lake Whatcom

Basin 1 48o 45.67’ 122o 24.69’ SW-S1-111401-8 8 NA 1.8 0.51 0.66 0.075 0.046

SW-S1-111401-24 24 5 6.4 1.06 .54 .527 .347

Basin 2 48o 44.56’ 122o 22.81’ SW-S2-111401-8 8 NA .8 .37 .29 .039 >.020

SW-S2-111401-19 19 2 2.8 2.56 1.4 1.63 1.33

Basin 3 48o 41.60’ 122o 28.19’’ SW-S3-111401-8 8 NA <.5 .61 .38 <.020 <.020

SW-S3-111401-23 23 NA .8 .73 .54 <.020 <.020

SW-S3-111401-30 30 67 .8 .77 .35 <.020 <.020

Water body Depth (m)

Calculated methyl-Hg Calculated particulate Calculated particulate methyl-Hg

Percentage of 

total Hg

Percentage of 

dissolved Hg ng/L Percentage of total mg/kg ng/L Percentage of total methyl-Hg mg/kg

Lake Whatcom 

Basin 1 8 15 7 NA NA NA 0.03 39 0.02

24 50 64 0.52 49 0.08 .18 34 .03

Basin 2 8 11 <7 .08 22 .10 >.019 >49 NA

19 64 95 1.16 45 .40 .30 18 .11

Basin 3 8 <3 <5 .23 38 >.46 NA NA NA

23 <3 <4 .19 26 .2 NA NA NA

30 <3 <6 .42 56 .5 NA NA NA

Mercury in Lake Whatcom and Other Lakes in Whatcom County 41 
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Figure 14. Estimated partitioning of mercury between the dissolved and particulate phases in five samples in the upper water 

column and two samples in the near-bottom water column of the three basins of Lake Whatcom, Washington.

Data are taken from calculated concentrations in table 11 from the original data of Exponent, Inc. (Gary Bigham, written commun., 2002). 

42 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Smallmouth Bass

Concentrations of Hg greater than 0.100 μg/g (wet 

weight) in the tissue of Lake Whatcom smallmouth bass were 

first reported for two composites of eight fish fillets collected 

from basins 2 and 3 in the autumn of 1998 (Serdar and others, 

1999). A more detailed study of smallmouth bass in May 

and June 2000 included analyses of fillets from 30 individual 

specimens collected from the near-shore region of each of the 

three Lake Whatcom basins (Serdar and others, 2001). 

More than 75 percent of the smallmouth bass collected 

from Lake Whatcom had total Hg concentrations greater 

than the tissue residue criterion for methyl-Hg of 0.30 μg/g. 

Chemists analyzed for total Hg, the criterion is based on 

methyl-Hg concentrations. Literature data suggests that most 

of the Hg in fish is methyl-Hg (Bloom, 1991). Significant 

correlations of Hg concentration with fish length (fig. 15) and 

with age were noted for each of the three basins. The study 

design included selection of 10 individual specimens within 

three size classes from each of the three basins. Mean and 

median concentrations of Hg in fish collected from basin 3 

were higher than those from basins 1 and 2 for all three classes 

(Serdar and others, 2001). Differences in average and median 

lengths and in average and median ages did not appear to 

account for the high Hg concentrations in smallmouth bass 

from basin 3. 

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Figure 14.—Continued.

Table 12. Concentrations of total mercury (Hg) at the intake 

gatehouse on Lake Whatcom, Washington

Month Year

Total Hg 

(nanograms 

per liter)

November 2002 0.77

December 2002 .65

January 2003 .79

February 2003 .73

March 2003 .83

April 2003 1.65

May 2003 .89

June 2003 1.67

Average 1.00

Standard deviation .41

Mercury in Lake Whatcom and Other Lakes in Whatcom County 43 
In order to investigate whether smallmouth bass 

collected from basin 3 of Lake Whatcom had statistically 

higher Hg concentrations than fish from basins 1 and 2, an 

analysis of covariance was applied to the entire data set of Hg 

concentrations from smallmouth bass from the lake, taking 

into account the confounding variable of length. No significant 

difference (p <0.05) in the slope of the Hg increase with 

length was found for the three basins. Hg concentrations in 

fish from basin 3 were higher than those in fish from basins 1 

and 2 (p <0.05) when length was considered as a confounding 

factor, regardless of whether an outlier value from basin 1 was 

included. A cursory examination did not reveal any obvious 

relations between the Hg concentration in specific specimens 

and the proximity of their collection location relative to the 

density of septic systems within 50 m of the lake. Therefore, 

the higher concentration of Hg in smallmouth bass from basin 

3 than smallmouth bass from basins 1 and 2 must be related 

to the biogeochemistry of the environmental systems or to 

differences in the physiology of the fish collected. 

Largemouth Bass

 Largemouth bass from lakes around the State of 

Washington (Fischnaller and others, 2003; Seiders, 2003) and 

from Tennant Lake (table 13) were analyzed for total Hg. 

For 17 Washington lakes that had sufficient variation in the 

size and age of fish specimens, the Hg concentrations in 

largemouth bass from 16 lakes showed a significant correlation 

with length and age, although a significant correlation with 

weight was observed for 15 lakes. Concentrations of Hg in 

fillets of largemouth bass from six lakes in Whatcom County 

are plotted in figure 16. This data set was subjected to an 

analysis of covariance, with length being the confounding 

factor. Because all specimens from Padden Lake except 

one were within a narrow length range, the data for Lake 

Padden was not included in the analysis of covariance. Hg 

concentrations in the fish from Lake Terrell, Lake Samish, 

Fazon Lake, Tennant Lake, and Wiser Lake were subjected 

to an analysis of covariance after disregarding the one outlier 

from Lake Samish. The slope of the Hg concentration versus 

length relation for Lake Terrell was lower than the slope of 

the relation for the other four lakes and was not included 

in the second step of the analysis of covariance. The ad 

hoc comparison of the results of the analysis of covariance 

indicates that Hg concentrations in largemouth bass from lakes 

in Whatcom County were highest in Tennant and Fazon Lakes, 

with concentrations in Lake Samish being significantly lower 

(p <0.05). In addition, the Hg concentrations in largemouth 

bass from Wiser Lake were the lowest and were significantly 

less than in the fish from Samish Lake. 

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Figure 15. Relation of concentration of mercury in fillets to total length of smallmouth bass in Lake Whatcom, 

Washington.

44 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Table 13. Concentrations of total mercury (Hg) and other characteristics of largemouth 

bass and yellow perch collected from Tennant Lake, Washington, May 10, 2002

[Gender: f, female; m, male. Age: Determined by Washington State Fish and Wildlife 

(WA F&W). Total Hg: Analyzed by Frontier Geosciences, Inc. mm, millimeter; g, gram; 

μg/g, micrograms per gram]

WA F&W 

scale No.

Sample 

No. Gender Length(mm)

Weight

(g)

Age 

(year)

Total Hg

(μg/g)

Largemouth Bass

1 1 m 327 587 8 0.309

2 2 f 327 680 6 .242

3 3 f 329 652 5 .195

4 4 f 337 677 7 .328

5 6 m 223 154 3 .138

6 7 f 225 154 3 .124

7 8 m 203 117 3 .103

Yellow Perch

13 14 m 259 243 5 0.126

14 15 m 203 108 3 .628

15 16 m 191 100 3 .0609

16 17 m 200 107 3 .0541

17 18 m 217 128 3 .0664

18 19 m 208 117 3 .0500

19 20 m 205 107 3 .0591

20 21 m 198 103 3 .0615

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Figure 16. Relation of concentrations of mercury in fillets to total length of largemouth bass in selected lakes of 

Whatcom County, Washington. 

Mercury in Lake Whatcom and Other Lakes in Whatcom County 45 
Cutthroat Trout

Cutthroat trout collected from the three basins of Lake 

Whatcom (Serdar and others, 2001; Seiders, 2003) and Lake 

Samish (this study) listed in table 14 were analyzed for Hg 

concentrations (fig. 17). No significant differences in the slope 

of the relation between Hg concentrations and fish length or 

the average Hg concentrations adjusted for length among the 

three Lake Whatcom basins were detected by the analysis of 

covariance tests. The Hg result for the single Lake Samish 

specimen that was analyzed fits among those found for Lake 

Whatcom. Cutthroat trout was the only species examined 

that exhibited increasingly higher Hg concentrations with 

decreasing conditioning factor for larger fish (fig. 18). The 

conditioning factor (mass divided by the total length to the 

third power) reflects the relative leanness of the fish specimen 

(Munn and Short, 1997). Fish with a low conditioning factor 

are lean (low weight for a given length) and may have lost 

mass without excreting their Hg. 

Table 14. Average concentrations of mercury (Hg) and other characteristics of cutthroat trout collected from Lake Whatcom and Lake 

Samish, Washington, 2000-01

[Values in parenthesis are range. Average concentrations are ± one standard deviation. μg/g, micrograms per gram; mm, millimeters; g, gram]

Lake

Number of 

fish samples 

collected

Hg

(μg/g)

Length

(mm)

Weight

(g)

Age range

(years) Reference

Lake Whatcom 

Basin 1 10 0.056 ± 0.014

(0.043 – 0.070) 

190 ± 30

(173 – 274)

65 ± 47

(38 – 195)

1 – 2 Serdar and others, 2001

Basin 2 10 0.065 ± 0.031

(0.031 – 0.116)

248 ± 51

(191 – 339)

162 ± 90

(58 – 320)

2 – 3 Serdar and others, 2001

Basin 3 10 0.067 ± 0.025

(0.032 – 0.116)

248 ± 51

(184 – 312)

130 ± 85

(47 – 260)

2 Serdar and others, 2001

12 0.083 ±0.026

(0.047 – 0.124)

317 ± 40

(241 – 373)

299 ± 80

(183 –453)

 3 – 5 Seiders, 2003

Lake Samish 1 0.033 241 136 1 This study

46 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure 17. Relation of concentration of mercury in fillets to total length of cutthroat trout in Lake Samish and 

the three basins of Lake Whatcom, Washington. 

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Figure 18. Relation of concentration of mercury in fillets to a conditioning factor for large cutthroat trout in Lake 

Whatcom, Washington.

Mercury in Lake Whatcom and Other Lakes in Whatcom County 47 
Yellow Perch

Hg concentrations and other characteristics of yellow 

perch collected from Lakes Whatcom, Padden, Samish, and 

Tennant Lake are summarized in table 15. Relation of Hg 

concentrations to total length of yellow perch in Tennant Lake 

and Lake Whatcom are shown in figure 19. Correlations of 

Hg concentrations with fish length were significant for all 

three Lake Whatcom basins, and with age in basins 2 and 

3 (Serdar and others, 2001). The Hg concentrations in fish 

from Lake Padden (0.059 ± 0.015 μg/g) and Tennant Lake 

(0.068 ± 0.024 μg/g) were similar, even though yellow perch 

from Tennant Lake (126 g) were twice as heavy, on average, 

as those analyzed from Lake Padden (62 g). Although the 

average length and weight of yellow perch that were analyzed 

from Lake Samish and Tennant Lake were similar, the average 

Hg concentration in fish from Lake Samish was 0.123 μg/g 

(±0.033 μg/g). 

The data from individual specimens from the three 

basins of Lake Whatcom and Tennant Lake were subjected to 

an analysis of covariance. The slope of the Hg versus length 

relation for basin 3 of Lake Whatcom was significantly higher 

(p <0.05) than those of basins 1 and 2 of Lake Whatcom and 

Lake Tennant.

Table 15. Average concentrations of mercury (Hg) and other characteristics of yellow perch collected from Lakes Whatcom, Padden, Samish, 

and Tennant Lake, Washington, 2000-02

[Values in parenthesis are a range. Average concentrations are ± one standard deviation. ND, not determined. μg/g, micrograms per gram; 

mm, millimeters; g, gram]

Lake

Number of 

fish samples 

collected

Hg

(μg/g)

Length 

(mm)

Weight 

(g)

Age 

range 

(years)

Reference

Lake Whatcom 

Basin 1 10 0.124 ± 0.070

(0.047 – 0.307) 

190 ± 32

(154 – 257)

79 ± 52

(35 – 210)

2 – 6 Serdar and others, 2001

Basin 2 10 0.174 ± 0.109

(0.070 – 0.374)

227 ± 60

(165 – 333)

200 ± 223

(44 – 680)

2 – 8 Serdar and others, 2001

Basin 3 10 0.290 ± 0.260

(0.085 – 0.869) 

219 ± 56

(157 – 310)

142 ± 124

(40 – 440)

2 – 7 Serdar and others, 2001

Lake Padden 8 0.059 ± 0.015

(0.046 – 0.092) 

170 ± 26

(150 – 229)

62 ± 34

(39 –141)

1 – 3 This study

 

Lake Samish 10 0.123 ± 0.033

(0.063 – 0.197)

212 ± 10

(203 – 231)

111 ± 18

(95 – 144)

3 – 4 This study

 

Tennant Lake 8 0.068 ± 0.024

(0.050 – 0.126)

210 ± 21

(191 – 259)

126 ± 48

(100 – 243)

3 – 5 This study

 

48 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Brown Bullhead

Ten brown bullhead (lengths of 186-288 mm) collected 

from basin 1 of Lake Whatcom were analyzed for Hg (Serdar 

and others, 2001) (fig. 20). The Hg concentrations of the fillets 

ranged from 0.031 to 0.121 μg/g and averaged 0.071 μg/g 

(table 16). One brown bullhead collected from basin 3 (275 

mm long) had a similar Hg concentration (0.138 μg/g). Two 

other brown bullhead from basin 3 were larger (335 and 356 

mm) and had much higher mercury concentrations (0.408 and 

0.784 μg/g). 

Average Hg concentrations were 5-fold less in eight 

brown bullhead collected from Lake Terrell (lengths of 

264-310 mm) than those from basin 1 of Lake Whatcom 

(table 16). Average Hg fillet concentrations were only 0.014 

μg/kg (ranging from 0.0063 to 0.023 μg/g) in 10 brown 

bullhead from Wiser Lake (lengths of 315-404 mm). Different 

analytical techniques used by the two studies could be partly 

responsible for the differences in Hg concentrations of brown 

bullhead. However, lack of analyses of standard reference 

material from both studies precluded the assessment of 

procedures. 

Other Species

Signal crayfish, pumpkinseed, and kokanee from Lake 

Whatcom also were analyzed for Hg (Serdar and others, 

2001). Correlations of Hg concentration with length were not 

significant for the three species, nor with age for pumpkinseed 

and kokanee. Hg concentrations in the tail muscle of signal 

crayfish generally were from 0.020 and 0.050 μg/g wet 

weight. Hg concentrations of pumpkinseed specimens 

were highly variable for basin 1 (ranging from 0.040 to 

0.230 μg/g) and basin 3 (ranging from 0.030 to 0.28 μg/g), 

compared to the range from 0.040 to 0.090 μg/g for basin 2. 

Hg concentrations in kokanee collected in 2000 were similar 

to those in specimens collected in 1998 (Serdar and others, 

1999); basin-wide average Hg concentrations in kokanee from 

the three basins of Lake Whatcom were within 30 percent of 

each other. 

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Figure 19. Relation of concentration of mercury in fillets to total length of yellow perch in Tennant Lake and Lake 

Whatcom, Washington. 

Mercury in Lake Whatcom and Other Lakes in Whatcom County 49 
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0 50 100 150 200 250 300 350 400

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Figure 20. Relation of concentration of mercury to total length of brown bullhead in Lake Whatcom, Washington. 

Table 16. Average concentrations of mercury (Hg) and other characteristics of brown bullhead collected from Lakes Whatcom and Terrell and Wiser Lake, 

Washington, 2000-01

[Values in parenthesis is a range. Average concentrations are ± one standard deviation. μg/g, micrograms per gram; mm, millimeters; g, gram]

Lake

Number of 

fish samples 

collected

Hg

(μg/g)

Length

(mm)

Weight

(g) Reference

Lake Whatcom

Basin 1 10 0.071 ± 0.026

(0.031 – 0.121) 

251 ± 27

(186 – 288)

0.232 ± 0.068

(0.087 – 0.032)

Serdar and others, 2001

Basin 3 3 0.443 ± 0.325

(0.138 –0.785)

322 ± 42

(275 – 356)

0.572 ± 0.271

(0.269 – 0.790)

Serdar and others, 2001

Lake Terrell 8 0.0186 ± 0.0072

(0.0134 – 0.0335)

282 ± 14

(264 – 310)

294 ± 54

(232 – 404)

This study

 

Wiser Lake 10 0.0141 ± 0.0065

(0.0063 – 0.023)

368 ± 24

(315 – 404)

795 ± 133

(483 – 987)

This study

 

50 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Biogeochemical Behavior of Mercury 

in Lake Whatcom

Present-day (2003) concentrations of Hg in various media 

and the observed relations provide a qualitative understanding 

of the behavior of Hg in Lake Whatcom. If no Hg is lost from 

the water column of Lake Whatcom, the volume-weighted 

total Hg concentration of the water inputs (regional and 

local atmospheric deposition, ground-water discharge, and 

tributary discharge) would equal the volume-weighted total 

Hg concentrations of the water outputs (Whatcom Creek and 

drinking-water withdrawals). The annual volume-averaged Hg 

concentrations of precipitation from the two nearest samplers 

of the national Mercury Deposition Network were greater 

than 6 ng/L. The average Hg concentrations of tributaries 

discharging to Lake Whatcom ranged from 3.2 to 5.8 ng/L. 

No data with low detection limits for Hg exist that could be 

used to assess the general concentration of Hg in ground water 

discharging directly into Lake Whatcom. In contrast, the 

average concentrations of total Hg in both the surface waters 

of Lake Whatcom (table 11) and of water pumped from Lake 

Whatcom for public supply (table 12) were significantly lower 

(1 ng/L or less) than any known inputs of water (tributary 

or regional precipitation). Because the Hg concentrations 

of the identifiable inputs of aqueous Hg to Lake Whatcom 

were significantly higher than the concentrations in the water 

column of the lake (the source of the removed water), total Hg 

must have been lost from the water column of Lake Whatcom.

The likely losses of total Hg from the water column of 

Lake Whatcom would include degassing of dissolved vaporous 

Hg (evasion), physical settling of Hg attached to particles 

of suspended sediment in tributary inflows, and chemical 

adsorption of dissolved Hg onto terrestrial or detrital particles 

that then settle to the lake bottom. Evasion of dissolved 

vaporous Hg (Hgo) was determined to be 7 percent of the total 

atmospheric deposition of Hg in another lake study (Watras 

and others, 1996), and thus is not considered an important loss 

term in the Hg mass balance of Lake Whatcom. In contrast, 

the strong relation between Hg and the percentage of fines 

in the surface sediments throughout all three basins (fig. 10) 

indicates that Hg is transported to the sediments primarily on 

fine-grained particles. This observation could be attributed 

either to the physical winnowing effect on the original 

tributary suspended matter as the coarser material settle out 

near the mouths of Lake Whatcom tributaries (as seen in 

fig. 10) or to the geochemical adsorption of dissolved Hg onto 

small organic and inorganic particles in the water column 

preceding settling. Assessing the relative importance of the 

physical settling of the original tributary particles versus the 

settling of particles on which additional Hg from that water 

column has adsorbed requires a well-constrained mass balance 

of particles.

Bioaccumulation of methyl-Hg through the food web 

is the primary pathway of Hg to the tissue of fish. Although 

methyl-Hg is present in both the bottom waters (fig. 14B) and 

sediments (fig. 11) of Lake Whatcom, there is insufficient 

information to develop an accurate conceptual model that 

could account for bioaccumulation of Hg in fish. In many 

lakes, total Hg in the sediments is correlated with TOC 

(Watras and others, 1996; Ullrich and others, 2001). Finegrained sediments seem to be more important than TOC in 

transporting Hg to the surface sediments of Lake Whatcom 

(fig. 10). For core samples in the deeper parts of the three 

basins, surface Hg concentrations varied by only 10 percent, 

whereas TOC varied by a factor of 2. Production of methylHg occurs primarily at the oxic/anoxic interface, whether in 

the water column or in the sediments. The production rate 

of methyl-Hg depends on temperature, pH, the availability 

of organic carbon, and the rate of sulfate reduction. The 

distribution of methyl-Hg in the sediments of the three basins 

of Lake Whatcom follows the same trend as TOC:

 basin 1 > basin 2 > basin 3.

The increasing concentration of methyl-Hg in the 

sediments with increasing TOC concentration may be a result 

of an increasing rate of sedimentary diagenesis. Increasing 

TOC concentrations in the sediments result in increasing 

rates of sulfate reduction. In turn, the rate of sulfate reduction 

has been shown to be a key factor in controlling the rates 

of methylation of Hg in the sediment column (MarvinDiPasquale and Agee, 2003). An alternative explanation 

suggests that the relationship between methyl-Hg and TOC 

is not related to the methylation rate but to the characteristics 

of the sediment. Methyl-Hg is known to have a higher 

binding affinity for organic-rich sediments. Therefore, this 

alternative explanation suggests that organic-rich sediments 

will more efficiently sequester the methyl-Hg in the interstitial 

porewaters of the sediments regardless of the Hg methylation 

rate. 

Data on the concentration and speciation of Hg in nearbottom and shoreline waters of basin 3 would lead to a better 

understanding of Hg cycling in the largest basin of Lake 

Whatcom and might help to explain the high concentrations 

of Hg in smallmouth bass collected in basin 3 relative to Hg 

concentrations in smallmouth bass collected in basins 1 and 2. 

Three observations provide some insight into the pathways of 

methyl-Hg to fish. The first set of observations relates to the 

input of methyl-Hg from sources of water to Lake Whatcom. 

The total methyl-Hg concentrations in Anderson Creek (0.15 

ng/L) and Austin Creek (0.13 ng/L), which drain into basin 

3, were higher than those in Silver Beach Creek, which 

drains into basin 1 (about 0.05 ng/L). However, methyl-Hg 

concentration was highest in the wetlands of the settling 

pond on Park Place in basin 1 (0.25 ng/L), but flow data were 

Biogeochemical Behavior of Mercury in Lake Whatcom 51 
not available for this source. In contrast, the majority of the 

nearshore (within 50 m of the lake) onsite septic systems 

are located within basin 3. Human waste and residential 

wastewater are known to contain small concentrations of Hg. 

It is expected that a higher proportion of the Hg discharged 

from these systems will be in the methyl-Hg form relative to 

other human-related sources of Hg. The lack of ground-water 

flow and Hg chemistry data precludes the evaluation of the 

loading of methyl-Hg from ground water, and whether it is 

from natural or anthropogenic sources. Secondly, the higher 

calculated particulate Hg in the surface waters of basin 3 

of Lake Whatcom (0.2 to 0.4 ng/L) than in the other basins 

(0.1 ng/L or less) could have led to a higher uptake of Hg 

by detrital feeding organisms that form the base of the food 

web (fig. 14A). Concentrations of Hg on the particles in the 

upper water column also were calculated to be higher in basin 

3 (0.2 to 0.5 mg/kg) than in basin 2 (0.1 mg/kg) (table 11). 

Finally, the higher ratio of Hg to TOC in surface sediments 

of basin 3 (4.3 ± 2.0 mg of Hg per kilogram of TOC) relative 

to basin 1 (1.9 ± 0.6 mg of Hg per kilogram of TOC) also 

could explain the higher concentrations of Hg in the tissue of 

smallmouth bass. In order for smallmouth bass or its prey to 

grow, they must eat organic carbon for both tissue growth and 

respiration. If that organic carbon enters the food web through 

benthic processes, the Hg:TOC signal in the sediments would 

be magnified up the food web as the major fraction of the 

organic carbon (that is, energy) is used for respiration. Thus, 

smallmouth bass and its prey would consume more Hg from 

the given amount of organic carbon of basin 3 than from the 

same amount of consumed organic carbon originating from the 

sediments of basin 1. 

Hg concentrations in smallmouth bass and yellow perch 

collected from the near-shore regions of basin 3 had higher 

Hg concentrations than other basins, but did not show any 

correlation with conditioning factor. In contrast, the native 

cutthroat trout did not exhibit higher Hg concentrations in 

basin 3 relative to basins 1 and 2, but the Hg concentrations 

were correlated with conditioning factor. Perhaps this 

observation is related to the home range, foraging behavior, 

and physiology of the various species.

 The concentration of total Hg in the sediments 

throughout Lake Whatcom is controlled by the Hg input 

to the drainage basin of Lake Whatcom and the grain-size 

distribution of the particles, which in turn is controlled by 

the physical processes of transport and settling acting on 

the particles. However, the presence of Hg in the water 

and sediment columns is not the limiting factor controlling 

Hg uptake by biota. Organic carbon plays a major role in 

controlling the transfer of Hg to the biota. The oxidation of 

organic matter in the sediments drives the reduction-oxidation 

processes that produce methyl-Hg in the sediment. Some of 

this methyl-Hg diffuses out of the sediment, as seen in the 

bottom waters in basins 1 and 2 (fig. 14B), and can be directly 

absorbed by the biota through respiration. The Hg associated 

with particulate organic carbon in the sediments or in the 

water column that enters the food web will be magnified at 

higher trophic levels. 

Mass Balances of Mercury in Lake 

Whatcom

The annual Hg inputs to Lake Whatcom were calculated 

using 2002 and 2003 data (table 17). The estimate for annual 

discharge of Hg from the tributaries was 179 g/yr 

(table 8); this is an underestimate, however, because storm 

events were not represented. For non-local atmospheric 

sources, the annual deposition rate of 6.2 μg/m2 of Hg (based 

on the average 1998–2002 for the Seattle Station in table 2) 

was applied over the 20 km2 surface of Lake Whatcom 

(table 1) to yield a non-local atmospheric deposition of 124 

g/yr. Known local sources of atmospheric Hg in Whatcom 

County in 2003 include the Bellingham sewage-sludge 

incinerator and the two oil refineries. Atmospheric deposition 

calculations that were developed for the sewage-sludge 

incinerator are categorized as having the lowest confidence 

because Hg speciation assumptions were based on indirect 

knowledge of the chlorine content of air chemistry (table 5). 

When the maximum estimated deposition for the three basins 

from the City of Bellingham sewage-sludge incinerators, 

which operated at 33 percent of total capacity in 2003 

(table 5), was applied to the surface areas of the three basins 

(fig. 1), a total input of 0.27 g/yr was estimated for local 

atmospheric sources. Deposition calculations were not 

attempted for the oil refineries because of the lack of data 

on the Hg species emitted by refineries. Likewise, the lack 

of precise Hg concentrations in ground water precluded an 

assessment of Hg inputs from direct ground water discharge 

to Lake Whatcom. Thus, the recent total input of Hg to Lake 

Whatcom was estimated to be 303 g/yr.

Table 17. Summary of recent annual inputs of sediment and mercury 

(Hg) from known sources to Lake Whatcom, Washington, 1998-2003

[Mg/yr, megagrams per year; g/yr, grams per year]

Inputs Data 

(years) 

Sediment 

sources 

(Mg/yr)

Hg 

sources 

(g/yr)

Percentage 

of known 

total Hg

Tributaries 2002-2003 272 179 59

Non-local atmospheric 1998-2002 negligible 124 41

Local atmospheric 2003 negligible .27 .1

Known total 272 303

52 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
In order to verify the sources of Hg to Lake Whatcom 

and understand the importance of any sources that have 

not been assessed or identified, the total sources of Hg 

must be balanced by the sinks of Hg. The foundations of a 

mass balance for any constituent in any lake are the mass 

balances of water and particles. The City of Bellingham has 

an extensive understanding of the water balance in Lake 

Whatcom, as a result of providing drinking water to its 

customers and replenishing water to Lake Whatcom through 

the Nooksack Diversion. However, little is known about the 

sources of particles to the lake sediments and their transport 

among the basins. A secondary product of a recent study 

of tributary Hg loading to Lake Whatcom (Norton, 2004) 

was the first lake-wide investigation of suspended-sediment 

concentrations in the tributaries to the lake. Using the TSS 

data from Norton (2004), the annual input of suspended 

sediment to Lake Whatcom was estimated to be 272 Mg in 

2002-03. The sinks of suspended matter from Lake Whatcom 

include sedimentation within the basins, and particles 

suspended in the water withdrawn from the lake. As a first 

approximation of the sinks of particles, the sedimentation rates 

obtained from the cores in each of the three basins of the lake 

were used to calculate the sink of particles from the water 

column. If the basin sedimentation rates from the cores are 

assumed to represent the average sedimentation rate for the 

entire area of the basin, then a total sedimentation of 8,225 Mg 

is calculated for Lake Whatcom. 

In most lakes, topographic relief of the lake bottom 

results in an uneven distribution of sediment accumulation. 

The accumulation of fine-grained sediments in the deep areas 

of lakes at rates greater than the average sedimentation for a 

lake is called sediment focusing. For a specific core location, 

a focusing factor is defined as the sediment accumulation rate 

at the site divided by the sediment accumulation rate averaged 

over the whole lake bottom. Because there was not enough 

material in each 1-cm section of the cores to determine grain 

size, the geomorphology of the core sites could not be related 

to other parts of the lake where sediment grain size has been 

measured. However, sediment focusing in the basins of Lake 

Whatcom was estimated by comparing the 210Pb inventory in 

the upper section of each core with the atmospheric deposition 

of 210Pb measured in western Washington (appendix D). The 

average sedimentation rate for each basin was then adjusted 

by dividing the sedimentation rate for the core taken from 

the deep areas of each basin by its focusing factor. The total 

sedimentation rate in Lake Whatcom then was estimated 

by summing the total sedimentation in each basin, which 

was calculated by multiplying the focus-adjusted average 

sedimentation rate for each basin by its surface area. After 

adjusting the sedimentation rates in the three cores for 

sediment focusing, the total annual sedimentation within Lake 

Whatcom was estimated to be 1,243 Mg, which was five times 

the estimated fluvial input. The total sinks of Hg from the 

Lake Whatcom water column cannot be calculated without 

a better understanding of the mass balance and dynamics of 

particles within Lake Whatcom. Likewise, the estimated total 

mass loading of sources of Hg to Lake Whatcom (table 17) 

cannot be verified until the sources of Hg are balanced by the 

total sinks of Hg.

Suggestions for Future Studies

The understanding of the sources and behavior of Hg in 

Lake Whatcom and the other freshwater lakes of Whatcom 

County is incomplete because of a lack of critical data and 

other information. Although the data collected since the 

inception of this project provide an initial understanding of the 

sources of Hg to Lake Whatcom, additional data are needed to 

reduce the uncertainty in and to identify processes that control 

the concentration of Hg in fish, water, and sediments of Lake 

Whatcom and other lakes in Whatcom County. This additional 

data could be obtained in study efforts with the following 

objectives:

A. Developing a better understanding of the sources, 

sinks, and dynamics of sediment and particulate Hg in 

Lake Whatcom. This would require:

1. Determining the TSS and concentrations of particulate and dissolved Hg in the tributaries of Lake 

Whatcom during the rising phase of the hydrograph of storm events; 

2. Collecting a series of sediment samples from 

the Nooksack Diversion and analyzing Hg in the 

numerous size fractions to assess whether differential settling and/or focusing of fine-grained 

sediments in the deep basin(s) of Lake Whatcom 

contribute to enriched Hg sediment concentrations; and

3. Resampling the sediments at the location of 

the cores and performing grain-size analyses to 

determine how the core sites relate to the overall 

sediment texture map of Lake Whatcom. If a relation between grain size and sedimentation rates 

can be established, then the total sedimentation of 

the lake can be quantified more easily. 

Suggestions for Future Studies 53 
B. Better quantifying the sources of Hg to Lake Whatcom. This would require:

1. Obtaining better Hg emissions and speciation 

data for current Hg sources in Whatcom County, 

including the City of Bellingham sewage sludge 

incinerator, the two refineries and the aluminum 

smelter when operating. Better emissions estimates of Hg from the industrial sources would be 

achieved by Hg emissions testing rather than estimates based on emission factors. In lieu of sophisticated Hg speciation measurements in the stack 

gases, the speciation of Hg could be estimated 

from better air chemistry data (e.g., chloride and 

sulfide concentrations) in the stack emissions. For 

the City of Bellingham sewage sludge incinerator, 

chloride air chemistry could be estimated based on 

the chloride concentration of sewage sludge that is 

incinerated. 

2. Using sensitive analytical techniques, determine 

Hg concentrations in ground water entering Lake 

Whatcom in a manner that would also assess the 

impact of Hg from septic systems.

C. Developing a better understanding of the biogeochemistry of Hg in Lake Whatcom and its effect on the 

bioaccumulation of fish. This would require:

1. Measuring the concentrations of dissolved, 

particulate, and methyl-Hg, and other important 

biogeochemical parameters (dissolved organic 

carbon, hydrogen sulfide, ammonium, pH, and 

TSS) in the water column of the deeper parts of 

basin 3 of Lake Whatcom; and 

2. Evaluating the methylation of Hg in habitats 

critical to fish growth and survival, especially if 

near-shore or benthic habitats are critical to the 

fish species of interest. 

Summary and Conclusions

Mercury (Hg) in the lakes of Whatcom County originated 

from atmospheric deposition of global sources of Hg, from 

atmospheric emissions of Hg from local incinerators and a 

chlor-alkali plant, and from erosion of drainage basin soils. 

Deposition of Hg from global sources has been decreasing 

since the 1980s. 

The operators of four major air-emission sources of Hg 

in Whatcom County that were examined in detail improved 

the control of their air emissions during the lifetime of the 

operations through changes in operating procedures or 

improvements in air-pollution control devices. Hg speciation 

data were not available from the four local air emission 

sources and source-specific Hg emissions data were available 

only for limited periods of the operational stages of the 

facilities. A simple air-deposition model with an analytical 

solution was developed that allowed relative comparisons of 

the Hg deposition to lakes or basins within a lake, based on 

measured or estimated Hg emissions, speciation of Hg in the 

emission source, prevailing annual wind pattern for the region, 

location of lakes or basins with respect to the sources, and 

residence times of the particulate, reactive, and vaporous Hg 

species in the atmosphere. 

The results of the estimates of atmospheric deposition 

derived from the model indicated that the three lakes north 

of Bellingham (Lake Terrell, Wiser Lake, and Fazon Lake) 

received the largest deposition of Hg from local air emission 

sources, primarily from the municipal waste incinerators 

during early stages of operation, when air pollution control 

was minimal (1974–91). The City of Bellingham sewage 

sludge incinerator, which was modernized in 1993, and 

the two oil refineries are the only known major local airemission sources operating in the region in 2003. Of the lakes 

modeled, the estimates of the air-deposition model indicated 

that basin 1 of Lake Whatcom is most affected by emission 

from the municipal sewage sludge incinerator. However, the 

estimated deposition of Hg to basin 1 from the sewage sludge 

incinerators was much less than the deposition to basin 1 from 

the municipal waste incinerators when they were operating. 

The chlor-alkali plant in the City of Bellingham began 

operation in 1964 and emitted Hg from three major sources 

until its closure in 2000: two vented air streams from the 

two sides of the electrolysis process (fume air and hydrogen) 

and fugitive emissions from the cell room. By 1979, the 

chlor-alkali plant had undergone a major expansion and 

modernization of its air-pollution control devices. Because 

basin 1 of Lake Whatcom is in the path of the prevailing 

winds passing through Bellingham, the deposition of Hg from 

any of the three emission sources from the chlor-alkali plant 

would be greatest for basin 1, with basin 2 of Lake Whatcom 

and Fazon Lake receiving 4-fold and 5-fold less deposition, 

respectively. Emissions of Hg from the fume air vent prior to 

the modernization in the late 1970s were likely in a chemical 

form that was deposited regionally, and this emission was 

virtually eliminated after modernization. Recent measurements 

of fugitive emissions of Hg from Hg hydrolysis cell rooms 

of chlor-alkali plants were 2- to 5-fold lower than estimates 

codified in Federal regulations. These modern measurements 

indicate that Hg escaping from cell rooms primarily was in 

the vaporous form, which adds to the global atmospheric 

inventory and does not settle near the source to any great 

extent. Estimates of maximum deposition of Hg to basin 1 

from fugitive emissions from the cell room of the chlor-alkali 

plant were higher than the maximum estimates from the City 

of Bellingham sewage sludge incinerator before modernization 

in 1993. The emissions of Hg from the hydrogen gas stream 

54 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
of the chlor-alkali plant were comparable to the fugitive 

emissions from the cell room. However, the hydrogen gas 

stream was not normally sent directly up the stack into the 

atmosphere as in the emission test, but the hydrogen gas was 

used as a fuel source for heating the lignin spray dryers. This 

plant configuration is unique among chlor-alkali plants in the 

United States and the deposition of Hg to nearby lakes could 

not be estimated because the speciation of the emitted Hg 

could not be evaluated.

Hg concentrations in largemouth bass and the enrichment 

of Hg in the sediments of six lakes in Whatcom County over 

time did not seem to be related to the estimated deposition 

from local emission sources. For instance, the estimated Hg 

depositions to Wiser and Fazon Lakes from local Hg sources 

were similar, but Hg concentrations in largemouth bass from 

Fazon Lake were much higher than bass from Wiser Lake 

for a given length. Likewise, the estimated deposition of Hg 

to Fazon Lake from local air emissions was slightly higher 

than those to Lake Terrell, yet maximum enrichments in Hg 

in the sediments of Lake Terrell from 1950 to 1990 were 

significantly higher than those of Fazon Lake. The enrichment 

in Hg in the sediments of a lake was dependent on the 

importance of surface-water inflows to the lake, rather than 

on estimated deposition of Hg from local air emissions. Lake 

Samish and Fazon Lake have little or no surface-water input 

and they exhibit similar enrichments of Hg in their sediments. 

The recent high-sensitivity Hg data from the City of 

Bellingham, Exponent, Inc., and Washington State Department 

of Ecology provide some insight into the behavior and sources 

of Hg in Lake Whatcom. Because the total Hg concentration 

of 1 nanogram per liter (ng/L) in the surface water of Lake 

Whatcom is considerably smaller than that in either the 

volume-averaged precipitation (from a Seattle site) or in 

tributary inflow water, Hg is being removed from the water 

column of Lake Whatcom and deposited within the sediments. 

Sedimentation of Hg in Lake Whatcom is controlled by the 

settling of fine-grained particles, either through the physical 

process of size fractionation or subsequent to chemical 

adsorption. In the low-oxygen, near-bottom waters of basins 

1 and 2 during autumn 2001, methyl-Hg was the dominant 

form of Hg. The lack of Hg data from the bottom waters of 

basin 3 precludes addressing any processes that resulted in 

the higher Hg concentrations in smallmouth bass and yellow 

perch in basin 3 relative to those in basins 1 and 2. However, 

the cycling of organic matter within the lake is ultimately 

controlling Hg concentrations in fish tissue. 

A lake-wide mass balance of Hg was attempted using 

data collected between June 2002 and May 2003. The Hg 

loadings in known sources of water to Lake Whatcom 

(precipitation and 10 tributaries) amounted to 303 grams 

per year (g/yr), with tributaries contributing 59 percent and 

direct precipitation contributing 41 percent. Although the 

concentration of total Hg in the water diverted from the 

Middle Fork Nooksack River through Anderson Creek was 

less than the average Hg concentration in the other creeks in 

the drainage basin, the total loading of Hg from the Nooksack 

Diversion was equal to the sum of other surface-water sources 

because of the large volume of water diverted. The estimated 

inputs of Hg to Lake Whatcom cannot be verified until they 

are balanced by the sinks of Hg to the sediments and by water 

withdrawals. The ability to develop accurate estimates of the 

sinks of Hg is hampered by an incomplete understanding 

of the sources, sinks, and dynamics of particles of Lake 

Whatcom. 

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58 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Appendix A. Analysis of Mercury in 

Fish and Assessment of Quality of Data 

Used in the Report

Methods for analyses of new data on Hg concentrations 

in fish from lakes in Whatcom County presented in this report 

are described below. 

Analysis of Mercury in Fish

Yellow perch from Lake Padden, Lake Samish, and 

Tennant Lake; brown bullhead from Lake Terrell and Wiser 

Lake; largemouth bass from Tennant Lake; and one cutthroat 

trout from Lake Samish were collected by the Washington 

State Department of Fish and Wildlife. After the fish samples 

were filleted and homogenized by En Chem (Green Bay, 

Wis.), Frontier Geosciences, Inc. (Seattle, Wash.) digested 

about 0.5 g of tissue from each sample with 10 mL of hotrefluxing 70-percent HNO3: 30-percent H2SO4 for about 2 

hours. The digests were then diluted to final volume of 40 

mL with a solution of 10-percent (v/v) 0.2 N BrCl. Aliquots 

of each sample were analyzed by stannous chloride (SnCl2) 

reduction, dual gold amalgamation, and analyzed by coldvapor atomic fluorescence spectrometry (CVAFS) according 

to standard operation procedures (Frontier Geosciences 

Inc., Seattle, Washington, written commun., 2003). The Hg 

concentrations in yellow perch and brown bullhead from Lake 

Padden, Lake Samish, and Wiser Lake could not be assigned 

to specific fish, and only averages of the individual specimens 

are reported. 

The Hg concentrations in fillets of smallmouth bass 

and cutthroat trout from Lake Whatcom and in fillets of 

largemouth bass and yellow perch in lakes in Whatcom 

County were subjected to the statistical analysis of covariance 

relative to fish length using the General Linear Models (GLM) 

procedure without transformation (SAS Institute, 1989). 

Significant differences in the slopes of the relation of Hg 

concentrations to fish length among basins and(or) lakes were 

evaluated. For those lakes in which differences in slopes were 

not significant, the differences in Hg concentrations among 

basins and(or) lakes were evaluated taking into consideration 

the lengths of the populations of fish analyzed as the 

confounding factor. 

Quality of Data

Mercury in Riverine Sources

Storm water entering Lake Whatcom was collected at 

three sites in the spring and autumn of 1998 by Washington 

State Department of Ecology (Ecology) and analyzed for 

total recoverable Hg with cold-vapor atomic absorption 

spectrometry (CVAAS) using ultra-clean techniques and the 

CETAC instrument (Serdar and others, 1999). The detection 

limit was 3 ng/L and the instrument calibration verification 

standard was 118 percent. Recovery of matrix spikes was 96 

percent (±20 percent) in the spring and 91 percent 

(±1 percent) in the autumn. The relative percent difference 

(RPD) of one field duplicate at 6 ng/L was 14 percent. 

Analyses of laboratory control samples were reported to have 

been within the prescribed acceptable range, but data were not 

provided.

Collection of monthly samples from terminus for the 

diversion of the Middle Fork Nooksack River were initiated 

by the City of Bellingham in August 2002; and the samples 

were analyzed for total Hg by Frontier Geosciences, Inc. 

using CVAFS (William McCort, City of Bellingham, written 

commun., 2003). Trip blanks were collected during six 

sampling periods and all trip blank concentrations were less 

than the reporting level of 0.15 ng/L. For each sampling 

period, Hg in the standard reference material (SRM) 1641d 

[National Institute of Standards and Technology (NIST), 

Gaithersburg, MD] was measured and resulted in an average 

recovery of 96 percent (±7 percent, n=11). The average 

recovery of two duplicate Nooksack River samples spiked at 

the 7 ng/L concentrations was 100 percent (±2 percent, n = 

4). The recovery of nine duplicate matrix samples spiked at 

concentrations ranging from 5 to 80 ng/L was 96 percent (±10 

percent, n = 18). The RPD of one laboratory duplicate was 9.9 

percent at a concentration of 1.85 ng/L. 

Bimonthly samples were collected by Ecology from 

10 tributaries between July 2002 and May 2003 (Norton, 

2004). The detection limit of the method was 2 ng/L, and 

concentrations in the field blanks were less than the detection 

limit. The RPD of four field duplicates ranged from 4 to 27 

percent at Hg concentrations from 2.5 to 6.4 ng/L. The two 

analyses of SRM NIST #1641d, diluted to 30.8 ng/L, were 

within 3 percent of the certified value. 

Appendix A 59 
Mercury in Ground Water

Ground-water samples were collected from the YRoad landfills by direct push sampling between October 19 

and November 2, 2001, and from domestic wells by BEK 

Engineering and Environmental, Inc. (2002a). A method blank 

of 100 ng/L was reported. The recoveries of two matrix spikes 

were 110 percent at 2,200 ng/L.

BEK Engineering & Environmental, Inc. (formerly 

BEK Purnell Engineering, Inc.) performed soil and groundwater assessments at the Hilltop (BEK Engineering & 

Environmental, Inc., 2002b) and Airport Woodwaste (BEK 

Engineering & Environmental, Inc., 2002c) landfill sites for 

Georgia-Pacific West, Inc. The detection limit for total Hg 

was 1,000 ng/L through 1995, when it decreased to 200 ng/L. 

At the Hilltop Woodwaste Landfill, soil samples also were 

analyzed with a method with a detection limit of 0.1 mg/kg. 

No other quality-assurance (QA) data were provided for this 

report.

Dr. Susan Cook collected four whole domestic water 

samples in the Whatcom Lake drainage basin in 1990 and 

sent them to Elemental Research of North Vancouver, British 

Columbia, Canada, for analysis of inductively-coupled 

plasma-mass spectrometry (ICP-KMS). This method has 

a detection limit of about 50 ng/L of Hg, depending on the 

concentration of dissolved solids. Samples were collected 

from the faucet of the well into acid-cleaned bottles provided 

by the analytical laboratory, after running water for 5 minutes. 

No other quality-assurance data were provided. Concentrations 

of aluminum (Al) and iron (Fe) concentrations in the wholewater samples were used to assess the presence of particles, 

and by inference, particulate Hg, in the samples.

Mercury in Lakes

Sediments

For the study in which lake sediments were collected 

(Serdar and others, 1999), the RPD for one field replicate 

was 1 percent and the RPD of one laboratory duplicate was 5 

percent. Analyses of laboratory control samples were reported 

to be within the acceptable range for Hg, but no data were 

presented. The recovery of one matrix spike was 102 

(±1 percent, n = 2).

The quality-assurance program for the collection, 

processing, and analyses of sediment core samples from 

five lakes in Whatcom County reported in this report and 

three core sediments in Lake Whatcom reported by Ecology 

(Norton, 2004) are grouped together because the samples were 

collected by the same USGS and Ecology personnel, using 

the same collection and processing techniques, and analyzed 

by, or contracted through, the same Ecology Manchester 

Environmental Laboratory and are described by Norton 

(2002). In addition, the procedures used for the analyses of 

30 grab samples of surface sediments are identical to those 

used to analyze the cores samples. Therefore, the qualitycontrol data reported here will reflect the overall quality of 

the analytical data for samples from both the eight cores and 

the 30 grab samples. Whereas, each of the field replicates for 

the surface grab samples were collected from a completely 

different sample, the duplicates from the core samples were 

taken from the same core section. 

The RPD in the determination of percentage of solids 

from two field replicates was less than 1 percent at percentage 

of solids contents of 17 and 27 percent. The RPD of the 

percentage of material in the dominant size fractions (fractions 

greater than 20 percent by weight) ranged from 0.4 to 11.3 

percent for duplicates of two surface sediment samples 

collected from Lake Whatcom. The relative standard deviation 

for triplicate laboratory analyses of total organic carbon 

(TOC) ranged from 0.3 to 6.9 percent for six samples. The 

RPD of field duplicates of two surface samples was less than 

4 percent, and the RPDs for TOC results of field splits from 

core samples from basins 1, 2, and 3 of Lake Whatcom were 

0.9, 1.1, and 33.4 percent, respectively. The stable Pb data 

was excellent, with the RPD for three field splits being less 

than 4 percent, and 7 percent for one laboratory duplicate. 

The Pb concentrations of all laboratory blanks were below 

the reported value of 0.003 mg/kg. The recoveries for matrix 

spikes was 102 ± 6.7 percent (n = 9) and 105 ± 7.6 (n = 9) for 

the recovery of a laboratory control standard. 

Quality-assurance data for total Hg consisted of 

laboratory blanks, laboratory replicates, laboratory control 

standards, field replicates (surface grab samples), field 

splits (core samples), blind standard reference materials, 

and interlaboratory comparisons. The quality-control data 

for analyses of total Hg generally was good, although the 

core samples from Fazon, Terrell and Wiser Lakes, and the 

bottom two sections from the Baker Lake core were analyzed 

in a second batch of analyses that was qualified because 

they exceeded the holding time. The Hg concentration of all 

laboratory blanks were less than the reporting value of 0.003 

mg/kg. The recovery of the laboratory control standards 

was 99.9 ±3.4 percent. Although the matrix spike recoveries 

satisfied the data-quality objectives, there seemed to be a small 

difference in the matrix spike recoveries among the batches 

of core samples analyzed. For the first three sets that were 

analyzed within the holding times, the matrix recoveries were 

99.8 ± 4.2 percent. The matrix recoveries for the last two sets 

that were qualified because of expired holding time were 91 ± 

1.4 percent. 

The RPD of total Hg in laboratory duplicates for 

two surface grab samples was 4 percent. At moderate Hg 

concentrations of 0.224 and 0.142 mg/kg, the RPDs of Hg in 

field duplicates of two surface grab samples were 5.4 and 0.7 

percent, respectively. The RPDs of total Hg in duplicate field 

splits from core samples from Lake Whatcom were less than 2 

percent for basins 1 and 2, and 19 percent for basin 3. 

60 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Because the three aliquots of the two SRM were submitted to 

the laboratory as dried samples, these SRMs samples (IAEA405 and MESS-3) can only be considered blind samples 

because the analysts probably knew they were SRMs but 

did not know the identity of the SRM. Three SRM aliquots 

were analyzed with the earlier batch of samples and three 

SRM aliquots analyzed in the latter batch that was qualified 

because of the expired holding time. The results of the Hg 

analyses of three aliquots of SRM MESS-3 averaged 0.108 ± 

0.038 mg/kg, compared to the certified value of 0.091 mg/kg 

(confidence interval between 0.082 and 0.100 mg/kg). The 

results of the SRM IAEA-405 averaged 0.85 ± 0.06 mg/kg, 

and compared favorably with the certified value of 0.81 mg/kg 

(confidence interval 0.77 to 0.85). The three analyses of SRM 

aliquots analyzed with the earlier batch of samples were 

within the certified values, and the RPD of Hg concentration 

for the one SRM samples analyzed in duplicate was 40 

percent. The analyses of the three SRMs aliquots analyzed 

with the later batch of samples generally seemed to produce 

higher concentrations than the earlier batch. Interlaboratory 

comparison of three sediment samples were analyzed by 

both the USGS Mercury Laboratory in Wisconsin and the 

Ecology Laboratory. Total Hg concentrations for the Ecology 

Lab generally were slightly higher than those from the USGS 

Mercury Laboratory at total Hg concentrations from 0.1 to 

0.2 mg/kg. The bottom 30-34 cm section of the basin 3 core 

of Lake Whatcom appeared to be contaminated, possibly 

from the bottom plunger of the core extractor. The Pb and 

Hg analyses were repeated for the 29-31 cm section. The 

percentage of solids and TOC analyses from the 30-34 cm 

section were used for the 29-31 cm section.

Quality-control data for methyl-Hg in the surfacesediment grab samples (Norton, 2004) consisted of the 

analysis of field replicates, blind standard reference materials, 

and interlaboratory comparisons. The RPD of methyl-Hg 

concentrations of one field duplicate sample, with an average 

concentration of 0.0025 mg/kg, was 36 percent. For two 

blind aliquots of the SRMs samples [International Atomic 

Energy Agency (IAEA-405)], the concentration of methyl-Hg 

reported by the Ecology Laboratory was 0.0047 ± 0.00051 

(1 standard deviation) mg/kg compared to the recommended 

value of 0.00549 mg/kg (95-percent confidence range from 

0.00496 to 0.00602 mg/kg) released by IAEA. Although the 

laboratory results were slightly below the confidence interval, 

the set of analyses from which the IAEA recommended value 

was calculated contained three analyses for which methyl-Hg 

concentrations were less than 0.0050 mg/kg. 

Two interlaboratory comparison surface grab samples 

were analyzed by the Ecology Laboratory and the USGS 

Mercury Laboratory. The methyl-Hg concentrations in 

aliquots from basin 3 were comparable between the two 

laboratories; however, the methyl-Hg concentration in the 

samples from basin 1 (LW 1-4) determined by the USGS 

Mercury Laboratory was twice as high as that of the Ecology 

Laboratory. This difference is likely due to the inhomogeneity 

of the surface samples. Samples of about 5 to 10 mL for 

methyl-Hg analyses were collected directly from the top 2 

cm of the grab, and transported separately to the respective 

laboratories. Only at the laboratory were the materials from 

the three grab samples mixed for analyses. Because there 

was no mixing in the field, variations in methyl-Hg within or 

between grab samples at a single station could result in the 

differences observed by the two laboratories.

Water

The Institute of Watershed Studies has been monitoring 

the water quality of Lake Whatcom since 1981. Prior to 2001, 

water-sample analysis for Hg by CVAAS (Mathews and 

others, 2002). Concentration greater than the detection limit 

of 200 ng/L was not detected in any samples. In 2001, special 

analytical tests were conducted using ICP-MS in which the 

method detection limit (MDL) was 50 ng/L. Hg concentrations 

were reported to be less than the MDL in 24 of the 25 samples. 

Hg concentration in the one remaining sample was reported 

to be 80 ng/L. Because the detection of Hg in just one sample 

represents 4 percent of the sample population and is only 60 

percent greater than the MDL, it is statistically possible that 

the detectable value of 80 ng/L was a false positive.

Exponent, Inc., collected 7 water samples from Lake 

Whatcom on October 11, 2001, using ultra-clean techniques 

and analyzed the samples for Hg and methyl-Hg by cold-vapor 

atomic fluorescence spectrometry (CVAFS) (Gary Bigham, 

written commun., 2002). The detection limit for total Hg was 

0.20 ng/L, and the RPD for one duplicate was 11.6 percent at 

a mean Hg concentration of 2.42 ng/L. The recovery of 10.1 

ng/L of Hg spiked into a lake sample was 94.1 percent, and 

the recovery of a SRM with a very high Hg concentration 

(NIST-1641d) averaged 94 percent. The detection limit for 

methyl-Hg was 0.020 ng/L and the RPD for a duplicate of one 

near-bottom lake water sample with an average methyl-Hg 

concentration of 0.504 ng/L was 9.3 percent. The recoveries of 

methyl-Hg in replicate near-bottom water samples spiked at 2 

ng/L of methyl-Hg were 78 and 85 percent.

The quality-assurance data for monthly samples of Lake 

Whatcom water from the drinking-water intake gatehouse, 

which were collected by the City of Bellingham beginning 

in November 2002, are given in the section, “Mercury in 

Riverine Sources.” 

Appendix A 61 
Mercury in Fish

 Hg in fish in Lake Whatcom and other lakes in Whatcom 

County was examined in four studies. Quality-assurance data 

were summarized in a limited study of eight fish (Serdar 

and others, 1999). For Hg, the concentration of Hg in the 

procedural blank was less than the detection limit, recoveries 

were within 25 percent of the spiked levels, the RPD of 

duplicate tissue samples was reported to be within 20 percent, 

and the analysis of SRM DORM-2 was within the accepted 

range. In the most extensive study, the method detection limits 

for the analyses of Hg in smallmouth bass, yellow perch, 

cutthroat trout, brown bullhead, kokanee, pumpkinseed, and 

signal crayfish from Lake Whatcom (Serdar and others, 2001) 

ranged from 0.005 to 0.010 μg/g wet weight. The average 

relative standard deviation for 15 laboratory replicates was 

9 percent and ranged from 2 to 19 percent. The recovery of 

19 matrix spikes was 84 percent and ranged from 72 to 98 

percent. Analyses of standard reference materials were not 

reported. 

Smallmouth bass, largemouth bass, and cutthroat trout 

caught by the Washington State Department of Fish and 

Wildlife were analyzed for Hg by the Washington State Toxics 

Monitoring Program of Ecology (Seiders, 2003). The median 

RPD of Hg in laboratory duplicates (n = 10) was 2 percent and 

the average was 8 percent (ranging from 0 to 31 percent for a 

largemouth bass from Fazon Lake). The median RPD for field 

duplicates (n = 11) was 4 percent with an average of 8 percent 

(ranging from 0 to 42 percent for largemouth bass from Lake 

Samish). The average recovery of Hg from fish matrix spiked 

at an unknown Hg concentration was 90 percent (±14 percent 

recovery) and the RPD of matrix spikes averaged 2 percent 

(ranging from 0 to 13 percent). The average recovery of Hg 

in the dogfish liver SRM (DOLT from National Research 

Council of Canada) was 100 percent (±8 percent) and was 90 

percent (±15 percent) for the dogfish muscle SRM (DORM)).

In this study, the method detection limit for analyses 

of Hg in cutthroat trout, yellow perch, brown bullhead, and 

largemouth bass collected from lakes in Whatcom County by 

the Washington State Department of Fish and Wildlife and 

analyzed by Frontier Geosciences, Inc. was 0.0005 μg/g (wet 

weight). The RPD for two laboratory duplicates was 7 and 10 

percent. The average recovery of two yellow perch spiked with 

0.3 μg/g Hg and two brown bullhead samples spiked with 0.07 

μg/g Hg was 99 percent (±4 percent). The average recovery of 

duplicate aliquots of the SRM DORM-2 was 86 percent 

(±5 percent).

References Cited

BEK Engineering & Environmental Inc., 2002a, Phase II 

Hydrogeologic investigation: Y-road landfills, Whatcom 

County, Washington: Ferndale, WA, 21 p. plus appendixes. 

BEK Engineering & Environmental Inc., 2002b, Annual report 

2002 landfill monitoring test results, Hilltop Woodwaste 

Landfill: Georgia-Pacific West, Inc., Ferndale, WA, 10 p. 

plus appendixes. 

BEK Engineering & Environmental Inc., 2002c, Annual report 

2002 landfill monitoring test results, Airport Woodwaste 

Landfill, Georgia-Pacific West, Inc., Ferndale, WA, 10 p. 

plus appendixes.

Mathews, R.A., Hilles, M., Vandersypen, J., Mitchell, R.J., 

and Mathews, G.B., 2002, Lake Whatcom Monitoring 

Project, 2000/2001 Final Report: Bellingham, Washington, 

Western Washington University, 423 p.

Norton, D., 2002, Quality assurance project plan: Mercury 

in sediments from Lake Whatcom and surrounding 

lakes: Determination of spatial and temporal patterns and 

characterization of tributary inputs: Olympia, Washington, 

Washington State Department of Ecology, No. 02-03-079. 

Norton, D., 2004, Mercury in sediments from Lake Whatcom: 

Determination of spatial and temporal patterns and 

characterization of tributary inputs: Olympia, Washington, 

Washington State Department of Ecology, NPI.

SAS Institute, 1989, SAS/STAT User’s guide, 4th Edition: 

Cary, North Carolina, v. 2. 

Seiders, K., 2003, Washington State Toxics Monitoring 

Program: Toxic fish tissue and surface water in freshwater 

environments, 2001: Washington State Department of 

Ecology, No. 03-03-012, 39 p. plus appendixes.

Serdar, D., Davis, D., and Hirsch, J., 1999, Lake Whatcom 

watershed cooperative drinking water protection project: 

Results of 1998 water, sediment, and fish tissue sampling: 

Olympia, Washington, Washington State Department of 

Ecology, Report No. 99-337, 66 p. plus appendixes.

Serdar, D., Johnston, J., Mueller, K., and Patrick, G., 2001, 

Mercury concentrations in edible muscle of Lake Whatcom 

Fish: Olympia, Washington, Washington State Department 

of Ecology, No. 01-03-012, 28 p. plus appendixes. 

62 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Appendix B. Estimates of 

Atmospheric Deposition to Lakes in 

Whatcom County for Sources Emitting 

a Hypothetical Unit of Mercury 

Emission in Bellingham, Ferndale, and 

at the Bellingham Airport

The simple model described here was developed to be 

used primarily to evaluate in a consistent manner the possible 

atmospheric deposition of mercury (Hg) to lakes in Whatcom 

County from past and present local sources of Hg. In the 

model, the three forms (species) of Hg (vaporous elemental, 

reactive gaseous, and particulate) initially emitted from a 

source are considered independently and the total deposition 

is the sum of the deposition of the three species. The reactivity 

of a species is characterized by its overall residence time 

in the atmosphere (τi) once it has been discharged from the 

source, cooled to ambient temperatures and is traveling within 

the local wind field. The depositional half-life of a specific 

species is the time it takes to remove one-half of that species 

of Hg from the atmosphere. The general kinetic rate constant 

for removal of each specific species from the atmosphere is 

defined as

In order to calculate the Hg concentration in the parcel 

of air once the plume has buoyantly risen and is traveling 

horizontally, the transport of Hg (Q in units of M T-1) through 

any plane perpendicular to the wind direction is

Appendix B 63

ki = ln(2) / �i , (B1)

where ki is in units of the inverse of time (T-1). 

The change in concentration of Hg for species i in any parcel 

of air within an expanding plume is defined as Appendix B 63

�Ci,x,y,z /�t = - ki � Ci,x,y,z , (B2)

where the concentration of Hg of species i in the parcel of air 

(Ci,x,y,z) is in units of mass/length3 (M L-3), and ∂Ci,x,y,z /∂t is in 

units of (mass/length3)/time or (M L-3 T-1). 

Because the change in the concentration of species 

i (–∂Ci,x,y,z/∂t) is due to the removal of species i, the 

contribution of this parcel of air to the gain of Hg to the earth’s 

surface (deposition) is simply –ki • Ci,x,y,z. The deposition rate 

of Hg species i (Depi) to an area of land or water below 

(M L-2 T-1) is the integration of the Hg losses from all parcels 

of air over the height of plume (dz). Appendix B 63

Depi = -� �Ci,x,y,z /�t dz = ki � Ci,x,y,z dz . (B3)

Qi = u �� Ci,x,y,z dy dz , (B4)

where u is the wind speed in units of L T-1 and dy dz is the 

planar extent of the plume. 

Because the change in the mass transport of Hg with time 

is simply the summation of losses of Hg over all the parcels of 

air in the plume that are moving past the plane perpendicular 

to the wind direction: 

dQi / dt = –ki Qi . (B5)

Equation B5 can be transformed from time coordinates to 

space (x) coordinates by recognizing that dt = dx/u, 

d Qi /dx = -(ki /u) Qi , (B6)

whose analytical solution is

Qi x� Qi� 0e

-ki/u x �

=, (B7)

where Qi,x is the mass transport of species i at distance x in the 

direction of the wind field and Qi,o is the transport at source, 

which will be defined as the mass emission from the source.

The derivations up to this point are generalized for any 

plume behavior in a steady-state wind field. Plume dynamics 

in this model were simplified by assuming that (1) species i

is completely mixed across the plane of the plume at a given 

x, and (2) the lateral expansion of the plume is constant, 

forming a cone in the xy plane with total angle of α. The 

width of the plume (y) at any given x is 2*tan(α/2) • x, which 

is approximated at small angles as tan(α) • x. Equation B4 is 

then simplified to

Qi,x = u� tan(�)��x � Ci,x dz . (B8)

Substituting the mass flux at a given x from equation B7 

on the left side of equation B8, and substituting 

Depi / ki (from equation B3) for ∫ Ci,x, dz yields

Qi� 0e

-ki/u x �

u � � � Depi/ki = � tan �

. (B9)

Appendix B 63 
Solving equation B9 for deposition of species i yields by varying the plume angle (α) from 5 to 20 degrees at a 

residence time of 1 week. This simplified model assumes 

steady-state conditions and assumes that a parcel of air will 

continue traveling in recorded wind direction at the recorded 

wind speed even if it takes several hours to reach the receptor. 

This model probably is not valid during light and variable 

wind conditions (about 20 percent of the time), when a 

radially expanding plume model would be more appropriate. 

Caution is advised when interpreting deposition calculations in 

which infrequent deposition occurs with low wind speeds. 

Table B1. Direction and distances from source of atmospheric mercury to 

receptor for lakes in Whatcom County, Washington

Receptor Direction 

(degrees)

Distance 

(miles)

Downtown Bellingham Source

Lake Whatcom

Basin 1 71 3.75

Basin 2 91 4.97

Basin 3 111 9.08

Baker Lake 91 39.80

Lake Terrell 312 12.21

Lake Samish 139 7.26

Wiser Lake 1 10.98

Fazon Lake 33 10.00

Ferndale Source

Lake Whatcom

Basin 1 118 8.13

Basin 2 120 9.94

Basin 3 124 14.62

Baker Lake 98 43.78

Lake Terrell 300 6.31

Lake Samish 142 13.39

Wiser Lake 33 7.21

Fazon Lake 69 9.73

Bellingham Airport Source

Lake Whatcom

Basin 1 119 6.31

Basin 2 121 8.12

Basin 3 126 12.82

Baker Lake 97 42.07

Lake Terrell 299 8.13

Lake Samish 145 11.76

Wiser Lake 18 7.22

Fazon Lake 60 8.59

Depi ki Qi� 0e

-ki/u x �

= � /�u � tan� � � � x�

 1

. (B10)

Note that the deposition is independent of the thickness 

of the plume. Although expanding the thickness of the plume 

will decrease the concentration of species i in the plume, 

deposition will occur over a longer air column (dz).

The simplifications of the plume dynamics allows one 

to use an analytical solution to estimate the deposition rate 

without having to numerically calculate the concentration 

of Hg species i in the air mass. Given a specific wind field, 

deposition at a given point from the source was calculated 

knowing only the emission rate of species i (Qi,0) and its 

residence time (τi). Equation B10 can be broken down into 

terms that are easily understandable. The Qi,0 /u represents the 

dilution of the emission source by the wind field, much as the 

initial concentration of a pollutant in a river resulting from a 

point source discharge is dependent on the velocity of a river.

The term e

-ki /u • x represents the decrease in the transport 

of the Hg species with distance from the source resulting 

from the deposition of species i between the source and 

distance x. The term 1/(tan(α) • x) represents the decrease 

in the concentration of species i in the plume by the lateral 

dispersion of the plume with distance from the source. The 

decrease in concentration in the plume results in a decrease in 

the estimated deposition at a point under the plume. 

Distances and directions from each major air emission 

source to eight target receptors (i.e., the location of the eight 

lake sediment cores) were determined (table B1). The model 

was applied using hourly wind speed and wind direction 

data from the Georgia-Pacific, Inc. (G-P) meteorological 

station (Axel Franzmann, Northwest Air Pollution Authority, 

Mount Vernon, Washington, written. commun., 2003) during 

1996 (fig. 6) because the wind data for 1995, the year of 

the last emission test, were incomplete. If the plume was 

above the target receptor (target receptor direction is within 

wind direction ± 1⁄2α), direct deposition of Hg to the site was 

calculated for that hour using equation B10 with the measured 

wind speeds at the G-P station in miles per hour, the distance 

from the source to the target receptor from table B1 in miles, 

and a standard plume angle (α) of 20 degrees. The hourly 

deposition amounts were summed over a year and the annual 

deposition was converted to SI units. The percentage of hours 

recording deposition at the specific receptor site (location of 

lake cores) in the year was calculated and the wind speeds for 

those hours recording deposition were averaged. Deposition 

for a unit emission of Hg (Q0 = 1 g/hr) for residence times 

of 1 day, 1 week, 1 month, 1 quarter-year, and 1 year were 

calculated. The sensitivity of the model results was tested 

64 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
As equation B10 indicates, the inverse of the residence 

time of the species being modeled (ln(2)/τi or ki ) is the 

primary factor controlling deposition (fig. B1). Because basin 

1 of Lake Whatcom is in the direction of a primary wind 

pattern from Bellingham, deposition occurs 13 percent of 

the year at an a of 20 degrees, leading to the highest level of 

estimated deposition (table B2). Estimated deposition for a 

unit Hg emission decreases rapidly in the southerly direction 

down Lake Whatcom because the frequency of depositional 

events decreases to about 4 percent in basin 2 and less than 

1 percent in basin 3. As with most source-receptor pairs, 

the model estimates of Hg deposition are insensitive to the 

value of the plume angle. As α decreases, the deposition per 

a depositional event increases because the plume over the 

receptor is more concentrated, but the frequency of deposition 

events likewise decreases because of the narrowness of 

the plume. Deposition rates of Hg in Lake Whatcom from 

Ferndale and Bellingham Airport sources are more than 

an order of magnitude less per unit Hg emission than a 

Bellingham source because the frequency of deposition is 

only 0.5 percent at average wind speeds of 1.8 mph (table B2). 

Because the location of the Georgia-Pacific source and the 

City of Bellingham sludge incinerator are relatively close to 

each other, deposition from the City of Bellingham sludge 

incinerator is approximated by the unit deposition calculated 

from the downtown Bellingham source (Georgia-Pacific, Inc., 

site).

Lake Terrell and Wiser and Fazon Lakes, all north of 

Bellingham and referred to as three northern lakes throughout, 

are in a secondary wind pattern for a Bellingham source. 

These lakes register deposition events between 4 and 8 percent 

of the year with average wind speeds from 7 to 10 mph 

(fig. B2A). The estimated deposition for a unit Hg emission 

is about an order of magnitude less than that of basin 1 of 

Lake Whatcom with annual deposition decreasing in order 

from Fazon Lake to Lake Terrell to Wiser Lake (table B2). 

The annual depositions to the three northern lakes from a unit 

Hg source in Ferndale (table B2) are slightly greater than that 

from a Bellingham source. The estimated deposition of Hg to 

Fazon Lake and Lake Wiser from a Ferndale source (fig. B2B) 

are about equal, whereas that to Lake Terrell is considerably 

less because of its location west of the source. When the wind 

data collected from a refinery in Ferndale (Axel Franzmann, 

Mount Vernon, Wash., written commun., 2003) was used to 

calculate deposition for a residence time of 1 week to the 

three northern lakes, the frequency of deposition decreased 

from about 6 percent to about 2.4 percent. This led to a 

decrease in deposition by factors between 2.5 and 3.0, and the 

trend among the lakes remained the same as the trend with a 

Bellingham wind field. 

The deposition to Fazon Lake for a unit Hg emission near 

the Bellingham Airport (table B2) is slightly greater than that 

from the Ferndale source because of the shorter distance to 

Fazon Lake, and therefore less lateral dispersion is modeled. 

In contrast, deposition to Wiser Lake from a unit emission 

of Hg from Ferndale is slightly greater than that from a 

Bellingham Airport unit source (fig. B2C).

Caution should be used when interpreting the estimates 

of Lake Samish deposition (table B2). For all three source 

locations, deposition registered only under light and variable 

wind conditions (less than 2 mph and less than 1 percent of the 

time) because little wind comes from the north, the direction 

of these sources in relation to Lake Samish. Deposition to 

Lake Samish from known Hg sources is best estimated with a 

radially expanding plume model. 

Although Baker Lake is in the direction of a primary 

wind pattern (2.6 to 3.9 percent frequency at about 5 mph), 

the long distance to Baker Lake (about 55 mi) and the effects 

of Mount Baker on the meteorology of the area make these 

estimates susceptible to large uncertainty. 

The deposition rates to target lakes described above 

is for a unit emission of Hg with a specific half-life. Only 

after (1) the emission rate from a specific source is known or 

estimated, (2) the speciation among the three species, i, has 

been assessed, and (3) half-lives of each of the three species 

have been assigned to each species can the total deposition of 

Hg (TotDep) to the water surface be calculated as the sum of 

the depositions from three species: 

TotDep = DepP + DepR + DepV , (B11)

where DepP is the deposition of particulate mercury, DepR is 

the deposition of reactive Hg, and DepV is the deposition of 

vaporous mercury. 

Appendix B 65 
Table B2. Deposition of mercury from an emission of 1.0 gram per hour from downtown Bellingham, Ferndale, and Bellingham Airport, 

Washington

[(μg/m2/)yr, micrograms per square meter per year; mph, miles per hour]

Lake Plume angle

(degrees)

Frequency of 

deposition

(percentage 

of year)

Windspeed

(mph)

Deposition of mercury [(μg/m2)/yr]

Residence time (days)

1 7 30 92 365

Downtown Bellingham

Whatcom

Basin 1 20 13.1 5.2 3.3 0.51 0.12 0.039 0.0099

10 7.35 5.0 .54

5 3.01 5.0 .41

Basin 2 20 3.93 5.3 .88 .14 .034 .011 .0028

10 2.00 5.7 .15

5 .94 6.1 .14

Basin 3 20 .96 3.0 .20 .045 .011 .0038 .0010

10 .39 2.0 .039

5 .22 1.8 .048

Samish 20 .59 1.5 .23 .052 .013 .0043 .0011

10 .36 1.6 .053

5 .14 1.5 .043

Baker 20 3.93 5.3 .055 .015 .0040 .0014 .0003

10 2.00 5.7 .015

5 .94 6.1 .014

Fazon 20 7.67 9.3 .49 .10 .026 .0088 .0022

10 3.89 9.3 .094

5 1.62 9.7 .067

Terrell 20 4.37 6.8 .26 .057 .014 .0049 .0012

10 2.27 6.4 .057

5 .80 6.3 .039

Wiser 20 5.42 10 .22 .040 .0094 .0032 .0008

10 3.02 9.5 .044

5 1.78 9.6 .047

Ferndale

Whatcom 

Basin 1 20 0.54 1.8 0.13 0.028 0.0067 0.0023 0.0006

10 .25 1.7 .026

5 .09 2.1 .016

Basin 2 20 .51 1.8 .098 .023 .0058 .0019 .0005

10 .22 2.1 .015

5 .09 2.6 .0089

Basin 3 20 .39 1.8 .041 .011 .0027 .0009 .0002

10 .21 1.9 .0098

5 .01 2.1 .0099

Samish 20 .63 1.5 .092 .026 .0067 .0025 .0006

10 .38 1.6 .027

5 .06 .58 .0152

66 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Ferndale—Continued

Baker 20 2.56 5.5 0.028 0.011 0.0031 0.0011 0.0003

10 1.2 5.7 .0088

5 .05 5.7 .0084

Fazon 20 12.1 5.0 .97 .17 .051 .017 .0043

10 4.81 4.8 .18

5 2.88 5.0 .15

Terrell 20 3.66 6.3 .69 .13 .031 .010 .0026

10 1.92 6.5 .11

5 .91 6.7 .13

Wiser 20 7.99 8.1 .82 .16 .039 .013 .0033

10 4.23 8.8 .18

5 2.03 9.3 .14

Bellingham Airport

Whatcom

Basin 1 20 0.53 1.8 0.22 0.042 0.0099 0.0033 0.0008

10 .24 2.1 .026

5 .10 2.3 .025

Basin 2 20 .51 1.8 .098 .023 .0077 .0019 .0005

10 .22 2.1 .015

5 .09 2.6 .0089

Basin 3 20 .42 1.8 .063 .017 .0042 .0014 .0004

10 .21 1.9 .015

5 .06 1.2 .015

Samish 20 .72 1.7 .13 .035 .0088 .0023 .0006

10 .38 1.6 .027

5 .06 .58 .015

Baker 20 2.68 5.5 .033 .012 .0034 .0012 .0003

10 1.36 5.9 .011

5 .58 6.4 .0088

Fazon 20 14.0 6.3 1.2 .21 .051 .017 .0043

10 7.79 6.5 .22

5 3.65 6.6 .21

Terrell 20 3.66 6.2 .41 .081 .020 .0067 .0017

10 1.79 6.3 .067

5 .86 6.0 .064

Wiser 20 8.80 1.4 .65 .13 .033 .011 .0028

10 4.54 1.6 .12

5 2.22 1.3 .11

Table B2. Deposition of mercury from an emission of 1.0 gram per hour from downtown Bellingham, Ferndale, and Bellingham Airport, 

Washington—Continued

[(μg/m2/)yr, micrograms per square meter per year; mph, miles per hour]

Lake Plume angle

(degrees)

Frequency of 

deposition

(percentage 

of year)

Windspeed

(mph)

Deposition of mercury [(μg/m2)/yr]

Residence time (days)

1 7 30 92 365

Appendix B 67 
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Figure B1. Deposition of mercury in Lake Whatcom from a source in downtown Bellingham, Washington.

68 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure B2. Deposition of mercury in lakes in Whatcom County from emission sources in downtown Bellingham, Ferndale, and Bellingham 

airport, Washington. 

Appendix B 69 
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70 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Appendix B 71 
Appendix C. Method for Calculating 

Missing Flow Data for the Tributaries 

of Lake Whatcom

The calculations of mercury (Hg) fluxes from each 

tributary of Lake Whatcom require knowledge of the annual 

discharge when used with total Hg concentrations determined 

six times between June 2002 and May 2003. Flow data 

from Smith, Austin and Anderson Creeks were not available 

during some periods within this one-year interval. Flow data 

from both Smith and Austin Creeks were not available until 

after February 5, 2003. Monthly averages of the ratios of the 

flows of Smith Creek to the flow of Austin Creeks that were 

calculated from water year 2002 were used to estimate missing 

data during the water year 2003. Missing flow data from Smith 

Creek in October 2002, November 2002, and December 1-10, 

2002, were estimated by multiplying the daily flows from 

Austin Creek by the ratio of Smith:Austin flows in October 

2001 (0.538), November 2001 (0.627), and December 2001 

(0.54), respectively. To account for the five days in December 

2002 for which both Smith and Austin data were missing, the 

total flows for the 26 days were increased by 19 percent. 

To estimate the flows in Austin Creek for December 

11- 31, 2002, January 2003, and February 1-4, 2003, the daily 

flow from Smith Creek was divided by the monthly Smith:

Austin flow ratio in December 2001 (0.54), January 2002 

(0.758) and February 2002 (0.61), respectively. During July 

2002, when the Nooksack Diversion was operating most of 

the time, the Anderson Creek gaging station did not record 

until July 21. The total monthly flow was based on the 

estimate of the diversion volume (2,260 million gallons; Peg 

Wendling, City of Bellingham, written commun., 2003) plus 

the base flows of Anderson Creek. A base flow of 5.5 ft3/s was 

obtained based on gaging station data during the morning of 

July 29, after flows had decreased as a result of the closing of 

the diversion at 1:45 pm on July 28. Data for Anderson Creek 

were not available for December 14, 2002 and the monthly 

volume calculation based on 30 days was increased by 3 

percent. 

Flows from Anderson Creek between February 4 and 

14, 2003, at a time when the diversion had been off except 

between 0:00 am and 10:00 am February 4, were estimated 

by multiplying the Austin Creek flows by the ratio of Austin:

Anderson Creek flows (1.32 ± 0.48). The daily volume flow 

from Anderson Creek on May 26, 2003 was estimated from 

the average daily volume flows for May 25 and May 27, 

during which time the diversion was operating. 

 On the basis of specific conductance, total Hg 

concentrations, and flow data, the sampling year was divided 

into a dry season (May through November) and a wet season 

(December through April). Monthly averages were used to 

calculate total monthly flows for the gaging stations monitored 

by the USGS (Silver Beach, Euclid, Mill Wheel, Brannian, 

Carpenter, and Olsen). Total dry season flows were calculated 

from the sums of the daily flows from June 1, 2002 through 

November 30, 2002 and from May 2003. Total wet season 

flows were calculated from the daily flows between December 

1, 2002 and April 30, 2003. When monthly flows could not be 

calculated, flows for the appropriate months from water year 

2002 and 2003 were substituted. In the worst case, the only 

available data from Mill Wheel Creek for the dry season was 

collected during July 2002. The July 2002 total monthly flow 

was multiplied by 7 to calculate the total dry season flow. 

72 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Appendix D. Analysis of Core 

Sections and Estimates of 

Sedimentation Rates in Lakes in 

Whatcom County

Collection of Sediment Cores and 

Preparation for Analysis

Sediment cores were collected from Lake Terrell, Lake 

Samish, Baker Lake, Wiser Lake, and Fazon Lakes from the 

Washington State Department of Ecology’s (Ecology) 8-m 

research vessel R.V. Skookum using a Wildco stainless-steel 

box corer fitted with a new, pre-cleaned 13×13×50-cm acrylic 

liner for each station. Stations were located and positions 

recorded using a differentially corrected global positioning 

system (GPS). The length of sediment cores recovered ranged 

from 50 cm in Wiser and Fazon Lakes to 27.5 cm in Lake 

Terrell. 

After retrieving an undisturbed core, overlying water 

was siphoned off and the core liner was removed from the 

stainless-steel box corer. The sediment core was extruded 

using a gear-driven piston that pushed the sediment column up 

at 1-cm increments and out the top of the liner. Each extruded 

1-cm section then was sliced off at the top of the core line 

using aluminum plates. The sides of the 13×13×1-cm layer 

were trimmed to prevent contamination from the liner or 

shallower sediment adhering to the liner. Each section was 

placed into an 8-oz glass jar with Teflon® lid liners that had 

been cleaned to USEPA specifications (U.S. Environmental 

Protection Agency, 1990), placed in plastic bags, and stored 

in coolers on ice pending processing in the laboratory. This 

process resulted in a maximum of 42 subsections per core. The 

bottom portion of each core (typically 4-6 cm) was sectioned 

into 2-cm intervals and the sediment section in contact with 

the bottom plate of the piston plunger was discarded. 

Sections for analysis were selected to represent current 

conditions (top layer), background conditions to calibrate 

radio-dating method, and representative intervals along 

the core length to reflect sediments deposited over several 

decades. Horizons not selected for initial analysis were frozen 

and archived to allow for future analysis. Sections selected for 

analysis were homogenized in the laboratory, and subsamples 

were split into various containers for analysis of total organic 

carbon (TOC), Hg, stable Pb, and radioactivity.

Before the collection of each core, the core liners and 

all utensils (aluminum plates and sampling spoons) that 

contacted samples were pre-cleaned by washing with Liquinox 

detergent, followed by sequential rinses with tap water, diluted 

(10 percent) nitric acid, deionized distilled water (DDI), and 

methanol. Between stations, the corer was thoroughly cleaned 

by brushing with onsite water. 

Methods of Analyses

Total Organic Carbon (Analyzed by Ecology)

Chilled samples were thawed to room temperature 

and homogenized. About 5-10 g of sample was added to 

weighed crucibles that had been dried at 70 °C and stored 

in a desiccator, and the weight of wet sample + crucible 

was recorded. Samples were then dried in the oven at 70 °C 

for at least 18 hours. The dried samples were placed into 

a desiccator to cool, and the weights of each of the dried 

samples + crucibles were recorded after coming to constant 

weight (about 3 hours). Samples were ground in a mortar and 

pestle and sieved. Several drops of 10-percent HCl were added 

to the blank and each of the samples to remove carbonates. 

Additional acid was added until no further effervescence 

occurred. The acid-treated samples were dried again at 70 °C 

for at least 18 hours before being re-ground, sieved, and stored 

in a desiccator until analysis.

Sample boats were scraped cleaned, rinsed with DDI 

water, heated for 30 minutes at 900 °C in a muffle furnace, and 

cooled. Five grams of the Standard Ottawa Sand was used as 

the method blank. Sediment samples were analyzed for total 

organic carbon (TOC) using a Shimadzu Model TOC-5050A 

Total Organic Carbon Analyzer equipped with a Shimadzu 

Model SSM-5000 Solid Sample Module. In this method, 

subsamples were combusted at 900 °C using high-purity 

oxygen as the carrier gas. The CO2 formed by the combustion 

is measured by the non-dispersive infrared detector (NDIR) 

and compared to a calibration curve. A 4-point calibration 

curve was developed using the peak area response of 0 to 

15 mg of glucose as the standard and was required to have a 

regression coefficient of at least 0.997. One-gram samples of 

standard reference materials (SRM) that were representative of 

the type of samples being analyzed were used for verification. 

Two aliquots of each sample weighing enough to result in a 

peak that is close to the upper limit of the calibration curve 

(250 to 500 mg) were added to clean sample boats. Qualitycontrol procedures included analyses of laboratory blanks, 

laboratory replicates, and SRMs. The resulting total carbon 

(TC) value is considered to be total organic carbon (TOC) 

because inorganic carbon was removed in the acidification 

step.

Appendix D 73 
Stable Lead (Analyzed by Ecology)

Samples for stable lead (Pb) analyses were oven dried 

at 105 ± 4 °C (usually overnight) and cooled. One gram of 

dried sample was transferred to a tared 250-mL beaker, to 

which 10 mL of 1:1 mixture of trace-metal grade HNO3

and DDI water was added. The sediment slurry was mixed, 

covered with a watch glass, heated to 95 °C, and refluxed for 

10 minutes without boiling. The slurry was allowed to cool, 

and an additional 5 mL of concentrated HNO3 was added. The 

beaker was covered and slurry was refluxed for 30 minutes. 

This last step was repeated to ensure complete oxidation. The 

solution was allowed to evaporate to 5 mL without boiling, 

while maintaining a covering of solution over the bottom of 

the beaker that was covered with a ribbed watch glass. After 

the solution was cooled, 2 mL of DDI water and 3 mL of 30 

percent H2O2 (low-metal content) was added. The beaker 

was covered with a watch glass and warmed on a hotplate to 

start the peroxide reaction, in such a manner as to ensure that 

losses did not occur due to excessively vigorous effervescence. 

Additional l-mL aliquots of 30-percent H2O2, up to a total 

volume of 10 mL, were added while warming until the 

effervescence was minimal or until the general sample 

appearance did not change. After effervescence subsided and 

the beaker was cooled, 5 mL 1:1 mixture of HCl and DDI 

water and 10 mL DDI water was added. The covered beaker 

was returned to the hotplate and heated for an additional 10 

minutes. The slurry was filtered through a 0.8-micron pre-acid 

washed membrane filter into a tared 125-mL polyethylene 

sample bottle and diluted to 100 mL, 101 g, with DDI water.

Sample material in solution was introduced by pneumatic 

nebulization into the Inductively Coupled Plasma Mass 

Spectrometer (ICP-MS) VG PQ ExCell, where a radiofrequency plasma transferred energy that caused desolvation, 

atomization, and ionization. The ions were extracted from 

the plasma through a vacuum interface and separated on the 

basis of their mass-to-charge ratio by a quadrupole mass 

spectrometer. The ions passing through the mass spectrometer 

are counted by a dual-stage discrete dynode electron multiplier 

detector. Daily startup procedures for the ICP-MS analysis 

included tuning for mass calibration, sensitivity, background, 

oxide formation, and double ionization. The instrument was 

calibrated daily using 1- to 20-μg/L standards prepared from 

100-μg/mL multi-element stock solutions (Spex QC-19 

and QC-7, High Purity Standards and Inorganic Venture). 

The sediment digests were diluted 1:10 with DDI, and 

internal standards having similar analytical behavior to the 

elements being determined were added before the solution 

was introduced into the ICP-MS. During the analytical run, 

instrumental drift and sample-matrix effects were corrected 

with changes in the sensitivity of the internal standards and 

the calibration verified by independent multi-element stock 

standard for ICP-MS.

Radioactive Tracers (Analyzed by Severn Trent 

Services, Richland, Washington)

210Pb was determined by low-energy photon gamma 

spectrometry following drying and sieving using EPA method 

901.1. 137Cs in sediments were determined in a similar manner 

using intrinsic hyperpure germanium gamma spectrometry. 

Detection limits for some samples, especially those at the top 

of the organic-rich cores near the sediment-water interface, 

were high because the samples sent to the laboratory did not 

contain enough solid material owing to the high percentage of 

water.

Total Mercury (Analyzed by Ecology)

Samples for analysis of total mercury (Hg) were 

pulverized and mixed well before weighing 1.00 ± 0.01 g of 

sediment into a stoppered, tared 250-mL biological oxygen 

demand bottle. DDI water (5.0 ± 0.1 mL) and 5.0 mL of aqua 

regia (three volumes of concentrated trace-metal-grade HCl 

to one volume of concentrated trace-metal-grade HNO3) was 

added and the bottle was placed in the covered water bath, 

where it was held for 2 minutes and 40 seconds at 91.5 °C. 

After removing from the water bath, the bottle was cooled to 

room temperature. DDI water (50.0 ± 0.5 mL) and 

15.0 ± 0.1 mL 5-percent potassium permanganate 

reagent was added and allowed to stand for 15 minutes. If 

the permanganate color did not persist, an additional 5 mL 

of permanganate was added. After adding 8.0 ± 0.1 mL of 

5-percent potassium persulfate reagent, the bottle was heated 

in a covered water bath at 91.5 °C for 40 minutes. After 

removing from bath and cooling, the excess solid brown 

permanganate at the bottom of the bottle was reduced with 

the addition of 6.0 ± 0.1 mL of a 1.73-M hydroxylamine 

hydrochloride solution and swirling vigorously under a hood. 

Additional hydroxylamine hydrochloride was added in 1.0 

± 0.1 mL increments and the bottle was swirled vigorously 

after each addition until the brown solid was no longer visible. 

After adding 55 ± 0.5 mL of DDI, samples were allowed to 

stand for at least 1 hour. If the supernatant was cloudy after 

standing, the sample was filtered through a pre-rinsed, 0.8-μm 

syringe filter before transferring to an analysis tube. 

With the CETAC M-6000A cold vapor Hg absorbance 

analyzer, a SnCl2 solution and the sample solution were 

pumped simultaneously into a mixing tee. The reaction of 

SnCl2 with Hg(II) resulted in the reduction of Hg(II) to Hg0. 

The mixture was pumped through a gas-liquid separator 

and drying tube into the sample absorbance cell with highpurity argon. Prior to analysis, the drying tube and flows on 

the CETAC M-6000A were checked. The amount of light 

absorbed at 253.7 nanometers was proportional to the Hg level 

in the sample.

74 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Calibration was performed using 4.0, 2.0, 1.0, 0.5, 0.25, 

and 0.0 μg Hg/L standards prepared from a secondary 1,000 

μg/L Hg standard diluted from the primary 100 μg/mL SPEX 

(Metuchen, NJ) Hg standard. The instrument was recalibrated 

if the correlation coefficient was less than 0.995. During the 

analytical run, calibration and procedural blanks, calibration 

verification standards, independent calibration verification 

standards, laboratory replicates, and laboratory control 

standards were performed. Concentrations calculations were 

based on peak height modeled from four highest readings. 

Quality-control samples for the core samples included 

procedural blanks, field splits, blind standard reference 

material, and interlaboratory duplicates.

The 30-34 cm section of the basin 3 core of Lake 

Whatcom appeared to be contaminated, possibly from the 

bottom plunger of the core extractor. The Pb and Hg analyses 

were repeated for the 29-31 cm section. The percentage of 

solids and TOC analyses from the 30-34 cm section were used 

for the 29-31 cm section.

Age Dating

The rates of sediment accumulation in the lakes must 

be known in order to correlate Hg concentrations in section 

cores at different depths with the dates in which the sediments 

initially were deposited, and to calculate Hg sedimentation 

rates. Sedimentation rates based on linear distances down the 

sediment core are sometimes skewed because interstitial water 

is squeezed out of the sediments by the weight of the overlying 

sediments, causing compression. In this report, sediment rates 

are based on sediment mass accumulation. In order to convert 

from a weight-to-weight basis of the percentage of solids 

measurement to a weight-to-volume basis that is needed to 

calculate mass accumulation, the porosity is defined as the 

percentage of volume occupied by water. The percentage of 

solids by weight is a function of the porosity of the section 

sample (Φ) and the densities of water (ρw= 1 g/cm3) and 

sediment grain (ρs) according to the equation:

Equation D1 is solved for porosity according to

Where percentage of solids were not measured, 

extrapolation between known values was used. The mass 

accumulation with depth in the core (g/cm2) is the cumulative 

masses of the overlying 1-cm thick sections. Six estimates 

of sediment accumulation rates [(g/cm2)/yr] were attempted 

using cumulative mass accumulation: (1) The decay of the 

210Pb (Schell, 1986), (2) the first appearance of stable Pb 

between 1920 and 1940, (3) the shape of the rise in elevated 

concentrations of stable Pb from first appearance to peak 

concentrations, (4) the peak concentration in 1975 of stable 

Pb due primarily to tetraethyl Pb in gasoline (Yake, 2001), (5) 

the first appearance of elevated concentration in 1953 of 137Cs 

as a result of atmospheric testing of thermonuclear weapons, 

and (6) peak concentrations of 137Cs in 1964 (Charles and 

Hites, 1987). The peak concentrations and first appearances 

of stable Pb and 137Cs are considered markers because these 

four features are associated with specific time marks. Constant 

sedimentation rates were assumed because consistent values 

were obtained on the basis of the above events and processes 

that represented time intervals ranging from 25 to 100 years. 

210Pb in the atmosphere is produced from the decay of 

atmospheric 222Rn and thus has a different pathway to lakes 

than natural stable Pb. 210Pb in the atmosphere is quickly 

scavenged onto atmospheric particles, which settle to the water 

and land surfaces. Once in the water column of lakes, the 

geochemical behavior of 210Pb will be similar to stable Pb and 

will quickly settle to the sediment-water interface by attaching 

onto particles. Once delivered to the sediment column, the 

210Pb on the particles will be buried by deposition of newly 

settling particles. 210Pb decays with a half-life of 22.6 years. 

Assuming that the sedimentation rate remained constant, 

the depth in the sediment at which the 210Pb radioactivity 

decreases to one-half of the surface value represents 22.6 

years of sedimentation. The sedimentation rate based on 210Pb 

activity is calculated from the slope of the linear regression 

of the natural log of the 210Pb activity, after correcting for 

the low level of the blank and activity supported by radium 

decay in the sediments, versus the mass accumulation rate 

with depth. For most cores for which 210Pb sedimentation rates 

were calculated, the sedimentation rates were based on only 

a few detectable measurements of 210Pb activity. In addition, 

there was significant scatter in the 210Pb data in some cores. 

Therefore, no assessment of the variation in sedimentation rate 

based on 210Pb activity was made. 

The sedimentation rate based on the peak in stable 

Pb was determined by dividing the accumulated mass 

sedimentation at the mid-point of the interval in which the 

peak Pb was found by 27 years (2002-1975). The confidence 

interval for the sedimentation rate based on stable Pb peak 

was determined by the broadness of the peak. The peak was 

defined as the mid-point of those sections in which Pb values 

are within 10 percent of the highest value. Because not all 

depth intervals were analyzed, the upper boundary of the peak 

is defined as the 1-cm section farthest away from the peak 

before measured Pb less than 90 percent of the peak value was 

Appendix D 73

percentage of solids �s (D1) � � 1 – �

�� � � �w � � + s� � 1 – � � = � ----------------------------------------------------------

� �1 percentage of solids – �

�percentage of solids/��s – percentage of solids-1�� = ----------------------------------------------------------------------------------------------------------------------------

Appendix D 73

(D2)

Given a sediment density of 2.7 g/cm3, the mass 

accumulation of a 1-cm section is calculated according to

Mass accumulation =�s� � 1 – �

Appendix D 73

(D3)

Appendix D 75 
encountered as the depth interval was decreased. Likewise, the 

lower boundary of the peak was defined by the 1-cm section 

prior to encountering a Pb value less than 90 percent of the 

peak value with increasing depth intervals. The same approach 

was used for the 137Cs peak as a marker for 1964 (38 years 

before present).

The first appearances of elevated concentrations of 

137Cs and stable Pb as a result of anthropogenic atmospheric 

inputs were used to assess the upper and lower limits of the 

average sedimentation rates during the last 50 and 75 years, 

respectively. The first appearance of elevated Pb values in 

sediments in western Washington lakes occurred between 

1920 and 1940 (Yake, 2001). In some cores, the natural 

variability in pre-industrial Pb concentrations makes it difficult 

to identify anthropogenic increases. The confidence intervals 

for long-term sedimentation rates based on first appearance 

of 137Cs and stable Pb incorporated both uncertainty in 

identifying first appearance of elevated concentrations in 

cores and uncertainty in the dates of anthropogenic influences 

within the region. The upper limit of the sedimentation rate 

for each core was calculated by dividing the accumulated 

mass sedimentation for the deepest section in which stable 

Pb first appeared to increase by 60 years (about 1940). The 

lower limit was calculated by dividing the accumulated mass 

sedimentation for the shallowest section in which stable Pb 

definitely increased above background by 80 years (about 

1920). Likewise, confidence intervals for sedimentation 

rates based on the first appearance of 137Cs were based on 

identifying the possible 1-cm section in which 137Cs first 

increased as defined by the years between 1952 and 1958. 

Given the range of sedimentation rates estimated from the 

five methods above, stable Pb concentrations were plotted with 

preliminary dates. Because grain size affects the magnitude of 

the enrichment in Pb, the concentrations were normalized to 

the maximum concentration. The sedimentation rates for the 

three Lake Whatcom cores then were adjusted manually until 

the shape of the rise of stable Pb matched among the three 

cores. Likewise, the shapes of the rise of Pb in the cores from 

the three lakes north of Bellingham (Terrell, Wiser, and Fazon) 

were matched. 

 Each sedimentation rate for a specific core was assigned 

a weighting factor (low, moderate, and high) based on the 

quantity and quality of the available data on which the 

estimate was based. A single estimate of the sedimentation 

rate for each core was derived by giving more consideration to 

estimates with highly weighted factors, while still satisfying 

the range for estimates with low weighting factors. A 

confidence level of high, moderate, or low was assigned the 

overall sedimentation rate, based on the consistency among the 

sedimentation rates derived from the different methods and the 

weighting factor of each result.

General Characteristics of the 

Sediment Column and Estimates of 

Sedimentation Rates in Lakes in 

Whatcom County

Eight sediment cores were collected from lakes in 

Whatcom County by USGS and Ecology personnel and the 

overall quality of the quality-assurance data was good. The 

data for the three cores from Lake Whatcom are reported in 

Norton (2004). Descriptions of the cores from five other lakes 

in Whatcom County are given in table D1 and the analytical 

results for selected core sections are summarized in table D2. 

Lake Whatcom Basin 1

Percentage of solids increased from 13.9 percent at the 

surface to about 19 percent in the sections between 3 and 8 cm 

(fig. D1). Below 10 cm, percentage of solids ranged from 14 to 

18 percent with a minimum observed at about 25 cm. The total 

organic carbon remained fairly constant throughout the core 

at values between 8 and 10 percent, except for one anomalous 

value of 18.1 percent at 11-13 cm. The top 16 cm appeared 

to be a layer of uniform brown silt. Wood debris was found 

between 16 and 19 cm. Between 32 and 44 cm, the sediment 

appeared to be a layer of compacted light brown clay. 

Three sections within the top 10 cm had detectable 210Pb 

values, and all six sections below 10 cm had undetectable 

values with an average 1/2 method detection limit (MDL) 

of 0.13 pCi/g. The 210Pb data indicate a sedimentation rate 

of 0.046 (g/cm2)/yr, which was assigned a low weighting 

factor because of the few detectable values. Stable Pb 

peaked in the 3-5 cm section and decreased to consistent 

low concentrations below 21 cm. Using Pb at 4 cm as the 

1975 marker, a sedimentation rate of 0.034 (g/cm2)/yr was 

calculated and given a high weighting factor. The confidence 

interval for this calculation was quite large [0.018 to 0.074 

(g/cm2)/yr] because measured values on both sides of the Pb 

peak were within 10 percent of the peak value. 137Cs exhibited 

a 3-point increase, reaching a peak concentration in 7-9 cm 

section and undetectable concentration in two sections below 

15 cm. Assigning 8 cm as the 1964 137Cs marker yielded a 

sedimentation rate of 0.050 (g/cm2)/yr [confidence level of 

0.032 to 0.072 (g/cm2)/yr], which was assigned a moderate 

weighting factor. 

76 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
The first appearance of elevated stable Pb between 14 

and 21 cm yielded a confidence interval ranging from 0.035 to 

0.068 (g/cm2)/yr when the marker was assigned dates between 

1920 and 1940, which was given a high weighting factor. The 

first appearance of 137Cs between 9 and 15 cm for the dates 

between 1953 and 1958 yielded a confidence interval between 

0.045 and 0.062 (g/cm2)/yr, which was assigned a moderate 

weighting factor. The increase of stable Pb using an initial 

estimate of the sedimentation rate of 0.045 (g/cm2)/yr matched 

the increase in stable Pb of the core from basin 2 of Lake 

Whatcom.

The maximum sedimentation rates for the four marker 

events were similar to the average rate calculated from the 

210Pb calculation (fig. D2 and table D3). Weighting the stable 

Pb profile higher than the 137Cs profile, a sedimentation rate of 

0.045 (g/cm2)/yr was assigned to this profile.

Lake Whatcom Basin 2

Percentage of solids increased from 15.3 percent at the 

surface to about 22 percent from 3 to 9 cm. Between 11 and 17 

cm, the percentage of solids were stable at 17.8 percent before 

increasing in the bottom 20 cm of the 44-cm core (fig. D3). 

TOC values were relatively stable between 5 and 6 percent 

in the top 5 cm, with slightly higher values of 6 percent 

found between 11 and 18 cm. Within the top 4 cm, small 

wood fragments and other black particles were observed, but 

otherwise the core appeared to be uniform gray silt throughout 

its length. 

Four values of 210Pb were detectable within the top 9 cm, 

and six undetectable values below 11 cm were determined to 

have an average 1/2 MDL of 0.4 pCi/g. Average sedimentation 

within the top 9 cm was calculated to be 0.105 (g/cm2)/yr. 

Because the regression coefficient of the slope of ln(excess 

210Pb) versus accumulated mass was only 0.916, the 210Pb 

sedimentation rate was assigned a low weighting factor. The 

stable Pb profile was uniform within the top 5 cm. Although 

an average or minimum sedimentation rate was not assigned, 

assigning the 1975 Pb peak marker to the 6-7 cm section that 

was not analyzed yielded a maximum sedimentation rate of 

0.059 (g/cm2)/yr. Assigning the 1964 137Cs marker to the 4-cm 

horizon yielded a sedimentation rate of 0.023 (g/cm2)/yr, with 

confidence intervals between 0.016 and 0.051 (g/cm2)/yr. The 

sedimentation rate based on the 137Cs peak marker was given a 

high weighting factor.

Stable Pb increased above background concentrations 

between the 14 and 17 cm horizons, which yielded minimum 

and maximum sedimentation rates of 0.039 and 0.063 

(g/cm2)/yr, respectively. The 1953 to 1958 first appearance 

of 137Cs occurred somewhere within the 10-16 cm section, 

yielding sedimentation rates between 0.047 and 0.079 

(g/cm2)/yr. The range of sedimentation rates calculated from 

the first appearance of the 137Cs and stable Pb were consistent 

and were given a moderate weighting factor. The increase of 

stable Pb using an initial estimate of 0.040 (g/cm2)/yr matched 

the increase in stable Pb in the core from basin 1 of Lake 

Whatcom.

Maximum sedimentation rates for the four marker events 

ranged from 0.051 to 0.079 (g/cm2)/yr, which was three 

times lower than the average rate calculated from the 210Pb 

calculation (fig. D2 and table D3). Therefore, the 210Pb data 

were disregarded. Satisfying all the minimum and maximum 

values for the highly weighted factors limited sedimentation 

rates between 0.016 and 0.051 (g/cm2)/yr, whereas a value 

greater than 0.039 (g/cm2)/yr is required to satisfy the 

moderately weighted first-appearance estimates (table D3). 

A sedimentation rate of 0.040 (g/cm2)/yr is assigned. 

Lake Whatcom Basin 3

The percentage of solids increased from 17.6 percent 

at the surface to 50 percent in the 6-8 cm section (fig. D4). 

Below 10 cm, percentage of solids ranged from 37 to 41 

percent. TOC decreased from 4.8 percent at the surface to 

about 2.5 percent between 3 and 8 cm. Between 10 and 22 cm, 

TOC ranged from 4 to 5 percent, but decreased to 2 percent 

in the 25-28 cm section. The percentage of solids, stable Pb, 

and 210Pb data all indicated a mixed layer in the top 2 cm. The 

stable Pb data indicated that the most contaminated mixed 

layer may extend down to 5 cm. Between 20 and 30 cm, the 

core is uniform silt containing visible plant material. Below 31 

cm, black layering was observed in the core.

The 210Pb sedimentation rate determined from data in 

the top 6 cm was 0.034 (g/cm2)/yr. Because the correlation 

coefficient was 0.97 for four points, this value was given a 

high weighting factor. Below 6 cm, the 210Pb concentration 

was undetectable at a MDL of 0.88 pCi/g in the 6-8 cm 

section, but the 10-12 cm section contained a detectable 210Pb 

concentration of 1.53 pCi/g. If the 10-12 cm data were used 

for the 210Pb dating calculation, the correlation coefficient 

decreased to 0.72 and the sedimentation rate increased to 

0.080 (g/cm2)/yr. This sedimentation rate was assumed to be 

the upper limit of the 210Pb method, and the upper limit is 

given a low weighting factor. The 1975 Pb peak marker lay 

within the top 5 cm, which yielded a maximum sedimentation 

rate of 0.074 (g/cm2)/yr. The one detectable 137Cs 

concentration and a small Pb peak in the 15-17 cm section 

are disregarded in the calculation of the sedimentation rate. 

When the increase in the normalized Pb concentration from 

basin 3 is matched to the increase in Pb for basins 1 and 2, the 

resulting sedimentation rate is 0.052 (g/cm2)/yr, which is given 

a moderate weighting factor. Given slightly more weighting to 

the 210Pb sedimentation value than the Pb matching value 

(fig. D2), a sedimentation rate of 0.040 (g/cm2)/yr is assigned 

(table D3).

Appendix D 77 
Lake Samish

The percentage of solids were 14.1 percent at the surface 

and were 29.2 percent between 6 and 11 cm (fig. D5). The 

data from two sections (1-2 cm and 3-5 cm, table D2) were 

disregarded. TOC decreased from 5.7 percent at the surface 

to 4.7 percent within the 6-8 cm section. The percentage of 

solids between 2 and 6 cm were linearly extrapolated using the 

TOC content. The uncertainty in the mass accumulation with 

depth adds considerable uncertainty to the sedimentation rate 

calculations, especially for those markers within or just below 

the zone of disregarded percent solid values (1-5 cm). The 

core appeared to be brown silt down to 25 cm, and the bottom 

6 cm appeared to be finer light brown silt. 

Four samples in the upper 8 cm contained detectable 

210Pb concentrations, but the decrease with depth appeared 

to be stepwise rather than a smooth decay. No attempt was 

made to calculate a sedimentation rate based on 210Pb. Stable 

Pb exhibited a distinct peak of 63 mg/kg within the 6-8 cm 

section, which yields a sedimentation rate of 0.072 (g/cm2)/yr 

(fig. D6 and table D3). 137Cs showed peaks both at the surface 

and within the 6-8 cm section, and no calculation based on 

the 1964 137Cs peak was attempted. The first appearance 

of 137Cs could have occurred somewhere between the 9-

cm and 12-cm horizons, translating into maximum and 

minimum sedimentation rates of 0.046 and 0.067 (g/cm2)/yr, 

respectively. Low concentrations of stable Pb were found 

below 20 cm and the first appearance of anthropogenic stable 

Pb could be located somewhere between 21 and 25 cm, 

yielding minimum and maximum sedimentation rates of 0.056 

and 0.082 (g/cm2)/yr, respectively (fig. D6). 

The Lake Samish core was assigned a sedimentation rate 

of 0.072 (g/cm2)/yr, primarily on the basis of the position of 

the stable Pb peak.

Lake Terrell

Percentage of solids ranged from 8 to 11 percent within 

the top 14 cm, before increasing to about 20 percent at the 

bottom of the 25-cm core (fig. D7). TOC increased smoothly 

from a concentration of 19.4 percent at the surface to 33 

percent in the 12-14 cm section, and then decreased to about 

to 16 percent at depth. The top of the core contained a silty 

layer. Wood fibers and plant material were observed between 

16 and 21 cm, with a limb lodged vertically within the core 

between 9 and 17 cm. Below 22 cm, the sediment appeared to 

be compacted silt and clay. 

Seven sections had detectable 210Pb concentrations and 

two concentrations at depth had an average 1/2 MDL of 0.62 

pCi/g. The decrease in 210Pb with depth was not smooth, 

resulting in a regression coefficient of 0.86 for the slope of the 

ln(excess 210Pb) versus depth. The average sedimentation rate 

was calculated as 0.095 (g/cm2)/yr. 

There was a broad maximum of about 90 mg/kg in stable 

Pb in the upper 11 cm, with a decrease in the 1-2 cm section. 

Below 12 cm, stable Pb decreases to 6.6 mg/kg within the 

bottom section (23-25 cm). If the 1975 horizon is assigned to 

the middle of the broad peak, a sedimentation rate of 0.029 

(g/cm2)/yr is calculated, although this value is given a low 

weighting factor because of the broadness of the peak and the 

second peak at the surface. A maximum sedimentation rate 

based on 1975 stable Pb peak being no deeper than 12 cm was 

0.046 (g/cm2)/yr, which was assigned a moderate weighting 

factor. Three sections between 3 and 14 cm contained 

detectable amounts of 137Cs with the peak located within the 

5-7 cm section, yielding a sedimentation rate of 0.029 

(g/cm2)/yr that was assigned a high weighting factor. Given 

that no 137Cs data was collected between 7 and 12 cm, the 

137Cs peak could have been as deep as 12 cm, yielding a 

maximum sedimentation rate of 0.047 (g/cm2)/yr. 

 The first appearance of 137Cs occurred somewhere 

between 15 and 18 cm, yielding minimum and maximum 

sedimentation rates of 0.031 and 0.048 (g/cm2)/yr, 

respectively, which were assigned a moderate weighting 

factor. Stable Pb concentrations in the bottom section 

(6.6 mg/kg) were near background concentrations, yielding 

minimum and maximum sedimentation rates of 0.038 and 

0.054 (g/cm2)/yr, respectively. Because lower values could 

have been present below 25 cm, sedimentation rates based 

on first appearance of elevated stable Pb were assigned a 

low weighting factor. Matching the rise of stable Pb with the 

profiles from Fazon and Wiser yielded a sedimentation rate of 

0.025 (g/cm2)/yr.

Maximum sedimentation rates from three markers ranged 

from 0.046 to 0.054 (g/cm2)/yr (fig. D6), whereas 210Pb decay 

indicates a sedimentation rate of 0.095 (g/cm2)/yr. The core 

was assigned a sedimentation rate of 0.031 (g/cm2)/yr, based 

primarily on the 1964 137Cs peak marker (0.047 (g/cm2)/yr) 

with a slight adjustment downward to match the stable Pb 

increase (table D3).

78 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Wiser Lake

The percentage of solids varied within a narrow range 

between 9 and 12 percent for this 44-cm core (fig. D8). TOC 

increased from 18 percent at the surface to 23.6 percent in the 

32-35 cm section. The top appeared to be disturbed, with the 

underlying sediment having a uniform appearance of black 

to brown silt with some organic materials. Woody debris was 

present between 14 and 16 cm.

210Pb concentrations in the top 2 cm were lower than 

those in the 7-9 cm section, which is consistent with the 

disturbed appearance of the top of the core. Below 20 cm, 

four core sections had undetectable 210Pb concentration 

with a 1/2 MDL of 0.44 pCi/g. Given the 210Pb profile, a 

sedimentation rate based on 210Pb decay was not attempted. 

Stable Pb exhibited a narrow peak of about 66 mg/kg 

between 11 and 16 cm. Assigning the 1975 stable Pb peak 

to the 12-cm horizon yields a sedimentation rate of 0.049 

(g/cm2)/yr, with a confidence interval between 0.041 and 

0.079 (g/cm2)/yr and a high weighting factor. Stable Pb 

decreased to 2.55 mg/kg in the 40-44 cm section. If this Pb 

concentration was the background level, then minimum and 

maximum sedimentation rates based on the first appearance 

of anthropogenic Pb were estimated to have been 0.049 and 

0.072 (g/cm2)/yr, respectively. Because it is possible, but not 

likely, that lower Pb concentrations could be present below 44 

cm, sedimentation rates based on first appearance of elevated 

stable Pb were assigned a moderate weighting factor. 137Cs 

was not detected in four sections of the core at a maximum 

MDL of 0.99 pCi/g.

 Based solely on the stable Pb profile, the sedimentation 

rate for Wiser Lake was estimated to be 0.049 (g/cm2)/yr 

(fig. D8 and table D3).

Fazon Lake

Percentage of solids generally increased from about 

7 percent at the surface to 11 percent within the 27-30 cm 

section before decreasing to 8 percent at the 40-44 cm section 

(fig. D9). TOC concentrations were high, ranging from 22 to 

28 percent. The core appeared uniform throughout its length. 

210Pb concentrations in the top 5 cm were either not 

detectable at MDL of 5 pCi/g or were lower than those in the 

7-9 cm section. 210Pb generally decreased down core, but was 

constant at detectable concentrations between 27 and 44 cm. 

A calculation based on the 210Pb decay between 7 and 30 cm 

yielded a sedimentation rate of 0.044 (g/cm2)/yr, which was 

assigned a low weighting factor. 

Stable Pb exhibited a sharp peak of 88 mg/kg within the 

11-13 cm section, which corresponds to a sedimentation rate 

of 0.035 (g/cm2)/yr (range 0.029 to 0.045 (g/cm2)/yr), which 

was assigned a high weighting factor. 137Cs was not found in 

the upper 5 cm at a maximum MDL of 2.6 pCi/g. Consistent 

with the stable Pb, a broad three-point peak in 137Cs was 

centered within the 15-18 cm section, yielding a sedimentation 

rate of 0.039 (g/cm2)/yr, which was assigned a moderate 

weighting factor. The minimum sedimentation rate calculated 

from the 137Cs peak was estimated to be 0.022 (g/cm2)/yr, but 

no maximum rate for either the peak or first appearance of 

137Cs could be calculated because no core sections below the 

137Cs peak were analyzed. 

Stable Pb concentration at the bottom of the core was 

13.3 mg/kg, which was higher than concentrations in the 

bottom of all the cores thought to represent a date before 1940. 

Because the bottom of the core may not have represented a 

pre-anthropogenic date, only a minimum sedimentation rate 

of 0.051 (g/cm2)/yr could be estimated and was given a low 

weighting factor. The sedimentation rate of 0.039 (g/cm2)/yr 

obtained from matching the shape of the stable Pb peak was 

consistent with the range obtained for the stable Pb peak and 

the 137Cs peak, and 0.039 (g/cm2)/yr was assigned a high 

weighting factor (fig. D6). A sedimentation rate for Fazon 

Lake was estimated to have been 0.049 (g/cm2)/yr, and was 

assigned a moderate confidence factor (table D3).

Baker Lake

Percentage of solids increased from 30 percent at the 

surface to values between 40 and 48 percent between 8 

cm and the bottom of the core at 27 cm (fig. D10). TOC 

concentrations were low (1.5 to 2.8 percent) throughout the 

core. The sediment texture was uniformly silt and clay with 

black layers first appearing at 3 cm. Wood debris was present 

below 16 cm. 

210Pb and stable Pb showed no distinctive patterns. In 

contrast, a concentration of 137Cs that was below the MDL 

(0.73 pCi/g MDL) was present at the surface, with a smooth 

increase of five core sections that were above the MDL 

reaching the maximum within the 21-23 cm section. Only a 

minimum mass-accumulation rate was calculated, based on the 

137Cs peak at the bottom of the core representing 1964 

(table D3).

These calculated time intervals are subject to same 

uncertainty of both individual estimates of sedimentation 

rates (figs. D2 and D6), as well as differences in the ranges 

among the six methods. Because each method is sensitive 

to sedimentation rates during different periods, difference in 

sedimentation rate among methods also may reflect changes 

in sedimentation rates with time or mixing of sediments near 

the sediment-water interface. Reconciling the differences in 

the ranges of sedimentation rates among the methods should 

decrease the uncertainty of the assigned sedimentation rate. 

Appendix D 79 
Sediment Focusing in Lake Whatcom

In most lakes, the topographic relief of the lake 

bottom results in an uneven distribution of sediments. The 

accumulation of sediments in the deep areas of lakes at rates 

above the average sedimentation for a lake is called sediment 

focusing. Because concentrations of particulate reactive 

metals, such as Pb and Hg, on suspended matter generally 

increase with decreasing particle size, differential settling of 

the different size fractions also focuses metal accumulation 

in deep depositional zones. Larger particles with lower-thanaverage metal concentrations settle out in shallow waters near 

mouths of the tributaries to Lake Whatcom, whereas finegrained particles with higher concentrations of particulate 

reactive metals travel farther and settle in deeper waters 

(Norton, 2004). Sediment focusing is addressed in this report 

solely for the purpose of assessing one possible reason for the 

imbalance of particle mass in Lake Whatcom. 

The effect of sediment focusing of sediment and 

particulate reactive metals in Lake Whatcom was attempted by 

comparing the atmospheric flux of 210Pb to the accumulation 

in the sediments (Appleby and Oldfield, 1992; Crusius and 

Anderson, 1995). The inventory of excess 210Pb down to a 

depth at which the concentration was undetectable (10-13 cm) 

was calculated for each core (table D4). Missing values within 

the core were estimated by using logarithmic extrapolations 

between the three to four detectable concentrations within 

each core. The steady state flux of excess 210Pb (table D4) 

was calculated by dividing 210Pb inventory by the mean life 

of 210Pb (32.2 years). A focusing factor then was derived by 

dividing the steady-state flux of excess 210Pb by atmospheric 

and fluvial inputs of 210Pb. The fluvial input of 210Pb was 

found to be insignificant (less than 0.005 (pCi/cm2)/yr) in Lake 

Sammamish, a lake of similar size in western Washington, 

and will be disregarded in the calculations for Lake Whatcom. 

The atmospheric deposition of 210Pb in western Washington 

has been measured at 0.13 ± 0.08 (pCi/cm2)/yr (Balistrieri 

and others, 1995), 0.14 (pCi/cm2)/yr (Barnes and others, 

1979), and 0.20 ± 0.11 (pCi/cm2)/yr (Nevissi, 1985). Using an 

average value of 0.155 (pCi/cm2)/yr, focusing factors of 11, 

12, and 6 were estimated for basins 1, 2, and 3 respectively. 

The focusing factors estimated above should not be applied 

to the mass balance of a constituent because the factors 

were calculated with core inventories of 210Pb derived from 

sediment cores with incomplete concentration data and high 

210Pb method detection limits.

References Cited

Appleby, P.G., and Oldfield, F., 1992, Application of lead-210 

to sedimentation studies, in Ivanovich, M., and Harmon, 

R.S., eds., Uranium-series disequilibrium: Applications 

to Earth, Marine and Environmental Sciences (2nd ed.): 

Oxford, Clarendon Press, p. 731-778.

Balistrieri, L.S., Murray, J.W., and Paul, B., 1995, The 

geochemical cycling of stable Pb, 210Pb, and 210Po in 

seasonally anoxic Lake Sammamish, Washington, USA: 

Geochimica Cosmochimica Acta, v. 59, no. 23, p. 4845-

4861.

Barnes, R.S., Birch, P.B., Spyridakis, D.E., and Schell, W.R., 

1979, Changes in the sedimentation histories of lakes using 

lead-210 as a tracer for sinking particles, in International 

Symposium on Isotope Hydrology, p. 875-898.

Charles, M.J., and Hites, R.A., 1987, Sediments as archives 

of environmental pollution trends, in Hites, R.A., and 

Eisenreich, S.J., eds., Sources and Fate of Aquatic 

Pollutants: Washington, D.C., American Chemical Society, 

p. 365-389.

Crusius, J., and Anderson, R.F., 1995, Sediment focusing in 

six small lakes inferred from radionuclide profiles: Journal 

of Paleolimnology, v. 13, p. 143-155.

Nevissi, A.E., 1985, Measurements of 210Pb atmospheric flux 

in the Pacific Northwest: Heatlh Physics, v. 48, p. 169-174.

Norton, D., 2004, Mercury in sediments from Lake Whatcom: 

Determination of spatial and temporal patterns and 

characterization of tributary inputs: Olympia, Washington, 

Washington State Department of Ecology, NPI.

Schell, W.R., 1986, Deposited atmospheric chemicals: 

Environmental Science & Technology, v. 20, no. 9, 

p. 847-853.

U.S. Environmental Protection Agency, 1990, Specifications 

and guidance for obtaining contaminant-free sample 

container: Office Solid Waste and Emergency Response, 

U.S. Environmental Protection Agency Directive #93240.0-

05. 

Yake, B., 2001, The use of sediment cores to track persistent 

pollutants in Washington State: Olympia, WA, Washington 

State Department of Ecology, No. 01-03-001, 44 p.

80 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Table D1. Sediment core logs for lakes in Whatcom County, Washington 

[Analysis: Pb-210, lead-210; Cs-137, cesium-137; T. Hg, total mercury; T. Pb, total lead; TOC, total organic carbon. Analytical sample No.: 

Sample in core sent out for analysis. Up to two sections may have been combined to form an analytical sample. cm, centimeter. –, no data]

Section Analysis

Analytical 

sample 

No.

Ecology 

sample

No.

Length 

(cm) Description Notes

Lake Samish (East Arm)

ID: Sam-1

Date collected: 9/23/02 12:30 PM

Latitude/Longitude: 48o39.898 N 122o23.099 W

Depth of water: 6.6 meters

1 Pb-210, Cs-137, T. Hg, T. Pb, TOC 1 40-8577 1 Brown silt with some organics No archive sample

2 Pb-210, T. Hg, T. Pb, TOC 2 40-8578 1 Brown silt with some organics No archive sample

3 Archive – – 1 Brown silt with some organics –

4 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 40-8579 1 Brown silt with some organics No archive sample

5 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 – 1 Brown silt with some organics No archive sample

6 Archive – – 1 Brown silt with some organics –

7 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 40-8580 1 Brown silt with some organics –

8 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 – 1 Brown silt with some organics –

9 Archive – – 1 Brown silt with some organics –

10 Pb-210, T. Hg, T. Pb, TOC 5 40-8581 1 Brown silt with some organics –

11 Pb-210, T. Hg, T. Pb, TOC 5 – 1 Brown silt with some organics –

12 Archive – – 1 Brown silt with some organics –

13 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 40-8582 1 Brown silt with some organics –

14 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 – 1 Brown silt with some organics –

15 Archive – – 1 Brown silt with some organics –

16 Pb-210, T. Hg, T. Pb, TOC 7 40-8583 1 Brown silt with some organics –

17 Pb-210, T. Hg, T. Pb, TOC 7 – 1 Brown silt with some organics –

18 Archive – – 1 Brown silt with some organics –

19 Pb-210, Cs-137, T. Hg, T. Pb, TOC 8 40-8584 1 Brown silt with some organics –

20 Pb-210, Cs-137, T. Hg, T. Pb, TOC 8 – 1 Brown silt with some organics –

21 Archive – – 1 Brown silt with some organics –

22 Archive – – 1 Brown silt with some organics –

23 Pb-210, T. Hg, T. Pb, TOC 9 40-8585 1 Brown silt with some organics No archive sample

24 Pb-210, T. Hg, T. Pb, TOC 9 – 1 Brown silt with some organics No archive sample

25 Archive – – 1 Brown silt with some organics –

26 Archive – – 2 Fine light brown silt –

27 Pb-210, T. Hg, T. Pb, TOC 10 40-8586 2 Fine light brown silt –

28 Pb-210, T. Hg, T. Pb, TOC 10 – 2 Fine light brown silt –

Lake Terrell

ID: Ter-1

Date collected: 9/24/02 9:30 AM

Latitude/Longitude: 48o51.819 N 122o41.182 W

Water depth: 0.6 meter

1 Pb-210, Cs-137, T. Hg, T. Pb, TOC 1 41-8566 1 Brown silt with organic material No archive samples

2 Pb-210, T. Hg, T. Pb, TOC 2 41-8567 1 Brown silt with organic material No archive samples

3 Archive – – 1 Brown silt with organic material –

4 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 41-8568 1 Brown silt with organic material No archive samples

5 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 1 Brown silt with organic material No archive samples

6 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 41-8569 1 Brown silt with organic material No archive samples

7 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 1 Brown silt with organic material No archive samples

Appendix D 81 
8 Pb-210, T. Hg, T. Pb, TOC 5 41-8570 1 Brown silt with organic material No archive samples

9 Pb-210, T. Hg, T. Pb, TOC 5 – 1 Brown silt with organic material – limb vertical 

(9-17)

No archive samples

10 Pb-210, T. Hg, T. Pb, TOC 6 41-8571 1 Brown silt with organic material – limb vertical 

(9-17)

No archive samples

11 Pb-210, T. Hg, T. Pb, TOC 6 – 1 Brown silt with organic material – limb vertical 

(9-17)

No archive samples

12 Archive – – 1 Brown silt with organic material- limb vertical 

(9-17)

 –

13 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 41-8572 1 Brown silt with organic material – limb vertical 

(9-17)

No archive samples

14 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Brown silt with organic material – limb vertical 

(9-17)

No archive samples

15 Archive – – 1 Brown silt with organic material – limb vertical 

(9-17)

 –

16 Pb-210, T. Hg, T. Pb, TOC 8 41-8573 1 Wood fibers and plant material in silt –limb 

vertical

No archive samples

17 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Wood fibers and plant material in silt –limb 

vertical

 –

18 Archive – – 1 Wood fibers and plant material in silt –

19 Pb-210, Cs-137, T. Hg, T. Pb, TOC 9 41-8574 1 Wood fibers and plant material in silt No archive samples

20 Pb-210, Cs-137, T. Hg, T. Pb, TOC 9 – 2 Wood fibers and plant material in silt –

21 Archive – – 2 Wood fibers and plant material in silt –

22 Pb-210, T. Hg, T. Pb, TOC 10 41-8575 2 Compacted silt and clay No archive samples

Wiser Lake 

ID: Wis-1

Date collected: 9/24/02 5:50 PM

Latitude/Longitude: 48o 54.207 N 122o 28.79 W

Water depth: 0.7 meter

1 Pb-210, Cs-137, T. Hg, T. Pb, TOC 1 41-8544 1 Black to brown silt with some organic material 

– slightly disturbed layer

No archive sample

2 Pb-210, T. Hg, T. Pb, TOC 2 41-8545 1 Black to brown silt with some organic material No archive sample

3 Archive – – 1 Black to brown silt with some organic material –

4 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 41-8546 1 Black to brown silt with some organic material No archive sample

5 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 – 1 Black to brown silt with some organic material –

6 Archive – – 1 Black to brown silt with some organic material –

7 Archive – – 1 Black to brown silt with some organic material –

8 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 41-8547 1 Black to brown silt with some organic material No archive sample

9 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 – 1 Black to brown silt with some organic material –

10 Archive – – 1 Black to brown silt with some organic material –

11 Archive – – 1 Black to brown silt with some organic material –

12 Pb-210, T. Hg, T. Pb, TOC 5 41-8548 1 Black to brown silt with some organic material No archive sample

13 Pb-210, T. Hg, T. Pb, TOC 5 – 1 Black to brown silt with some organic material –

14 Archive – – 1 Woody debris –

15 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 41-8549 1 Woody debris No archive sample

Table D1. Sediment core logs for lakes in Whatcom County, Washington—Continued

[Analysis: Pb-210, lead-210; Cs-137, cesium-137; T. Hg, total mercury; T. Pb, total lead; TOC, total organic carbon. Analytical sample No.: 

Sample in core sent out for analysis. Up to two sections may have been combined to form an analytical sample. cm, centimeter. –, no data]

Section Analysis

Analytical 

sample 

No.

Ecology 

sample

No.

Length 

(cm) Description Notes

82 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
16 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 – 1 Woody debris –

17 Archive – – 1 Black to brown silt with some organic material –

18 Archive – – 1 Black to brown silt with some organic material –

19 Archive – – 1 Black to brown silt with some organic material –

20 Archive – – 1 Black to brown silt with some organic material –

21 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 41-8550 1 Black to brown silt with some organic material –

22 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Black to brown silt with some organic material –

23 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Black to brown silt with some organic material –

24 Archive – – 1 Black to brown silt with some organic material –

25 Archive – – 1 Black to brown silt with some organic material –

26 Archive – – 1 Black to brown silt with some organic material –

27 Pb-210, T. Hg, T. Pb, TOC 8 41-8551 1 Black to brown silt with some organic material –

28 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Black to brown silt with some organic material –

29 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Black to brown silt with some organic material –

30 Archive – – 1 Contact change brown silt layer –

31 Archive – – 1 Light brown silt layer –

32 Archive – – 1 Light brown silt layer –

33 Pb-210, T. Hg, T. Pb, TOC 9 41-8552 1 Light brown silt layer –

34 Pb-210, T. Hg, T. Pb, TOC 9 – 1 Light brown silt layer –

35 Pb-210, T. Hg, T. Pb, TOC 9 – 1 Light brown silt layer –

36 Archive – – 1 Light brown silt layer –

37 Archive – – 1 Light brown silt layer –

38 Archive – – 1 Light brown silt layer –

39 Archive – – 1 Light brown silt layer –

40 Archive – – 1 Light brown silt layer –

41 Pb-210, T. Hg, T. Pb, TOC 10 41-8553 2 Light brown silt layer –

42 Pb-210, T. Hg, T. Pb, TOC 10 – 2 Light brown silt layer –

Fazon Lake

ID: Faz-1

Date collected: 09/24/02 1:40 PM

Latitude/Longitude: 48o 51.908 N 122o 22.039 W

Depth of water: 1.5 meters

1 Pb-210, Cs-137, T. Hg, T. Pb, TOC 1 41-8555 1 Uniform fine brown silt No archive sample

2 Pb-210, T. Hg, T. Pb, TOC 2 41-8556 1 Uniform fine brown silt No archive sample

3 Archive – 1 Uniform fine brown silt –

4 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 41-8557 1 Uniform fine brown silt No archive sample

5 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 – 1 Uniform fine brown silt No archive sample

6 Archive – – 1 Uniform fine brown silt –

7 Archive – – 1 Uniform fine brown silt –

8 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 41-8558 1 Uniform fine brown silt No archive sample

9 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 – 1 Uniform fine brown silt No archive sample

10 Archive – – 1 Uniform fine brown silt –

11 Archive – – 1 Uniform fine brown silt –

12 Pb-210, T. Hg, T. Pb, TOC 5 41-8559 1 Uniform fine brown silt No archive sample

13 Pb-210, T. Hg, T. Pb, TOC 5 – 1 Uniform fine brown silt No archive sample

14 Archive – – 1 Uniform fine brown silt –

Table D1. Sediment core logs for lakes in Whatcom County, Washington—Continued

[Analysis: Pb-210, lead-210; Cs-137, cesium-137; T. Hg, total mercury; T. Pb, total lead; TOC, total organic carbon. Analytical sample No.: 

Sample in core sent out for analysis. Up to two sections may have been combined to form an analytical sample. cm, centimeter. –, no data]

Section Analysis

Analytical 

sample 

No.

Ecology 

sample

No.

Length 

(cm) Description Notes

Appendix D 83 
15 Archive – – 1 Uniform fine brown silt –

16 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 41-8560 1 Uniform fine brown silt –

17 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 – 1 Uniform fine brown silt –

18 Pb-210, Cs-137, T. Hg, T. Pb, TOC 6 – 1 Uniform fine brown silt –

19 Archive – – 1 Uniform fine brown silt –

20 Archive – – 1 Uniform fine brown silt –

21 Archive – – 1 Uniform fine brown silt –

22 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 41-8561 1 Uniform fine brown silt –

23 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Uniform fine brown silt –

24 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Uniform fine brown silt –

25 Archive – – 1 Uniform fine brown silt –

26 Archive – – 1 Uniform fine brown silt –

27 Archive – – 1 Uniform fine brown silt –

28 Pb-210, T. Hg, T. Pb, TOC 8 41-8562 1 Uniform fine brown silt –

29 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Uniform fine brown silt –

30 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Uniform fine brown silt –

31 Archive – – 1 Uniform fine brown silt –

32 Archive – – 1 Uniform fine brown silt –

33 Archive – – 1 Uniform fine brown silt –

34 Pb-210, T. Hg, T. Pb, TOC 9 41-8563 1 Uniform fine brown silt –

35 Pb-210, T. Hg, T. Pb, TOC 9 – 1 Uniform fine brown silt –

36 Pb-210, T. Hg, T. Pb, TOC 9 – 1 Uniform fine brown silt –

37 Archive – – 1 Uniform fine brown silt –

38 Archive – – 1 Uniform fine brown silt –

39 Archive – – 1 Uniform fine brown silt –

40 Archive – – 1 Uniform fine brown silt –

41 Pb-210, T. Hg, T. Pb, TOC 10 41-8564 2 Uniform fine brown silt –

42 Pb-210, T. Hg, T. Pb, TOC 10 – 2 Uniform fine brown silt –

Baker Lake

ID: Bak-1

Date collected: 9/26/2002 11:39: AM

Latitude/Longitude: 48 o 43.700 N 122o 37.082 W

Water depth: 15.3 meters

1 Pb-210, Cs-137, T. Hg, T. Pb, TOC 1 41-8534 1 Light brown fine silt and clay No archive sample

2 Pb-210, T. Hg, T. Pb, TOC 2 41-8535 1 Light brown fine silt and clay No archive sample

3 Archive – – 1 Beginning of reducing layer (black streaks) –

4 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 41-8536 1 Light brown fine silt and clay No archive sample

5 Pb-210, Cs-137, T. Hg, T. Pb, TOC 3 – 1 Light brown fine silt and clay –

6 Archive – – 1 Light brown fine silt and clay –

7 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 41-8537 1 Light brown fine silt and clay –

8 Pb-210, Cs-137, T. Hg, T. Pb, TOC 4 – 1 Light brown fine silt and clay –

9 Archive – – 1 Light brown fine silt and clay –

10 Pb-210, Cs-137, T. Hg, T. Pb, TOC 5 41-8538 1 Light brown fine silt and clay –

11 Pb-210, Cs-137, T. Hg, T. Pb, TOC 5 – 1 Light brown fine silt and clay –

Table D1. Sediment core logs for lakes in Whatcom County, Washington—Continued

[Analysis: Pb-210, lead-210; Cs-137, cesium-137; T. Hg, total mercury; T. Pb, total lead; TOC, total organic carbon. Analytical sample No.:

Sample in core sent out for analysis. Up to two sections may have been combined to form an analytical sample. cm, centimeter. –, no data]

Section Analysis

Analytical 

sample 

No.

Ecology 

sample

No.

Length 

(cm) Description Notes

84 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
12 Archive – – 1 Light brown fine silt and clay –

13 Pb-210, T. Hg, T. Pb, TOC 6 41-8539 1 Light brown fine silt and clay –

14 Pb-210, T. Hg, T. Pb, TOC 6 – 1 Light brown fine silt and clay –

15 Archive – – 1 Light brown fine silt and clay –

16 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 41-8540 1 Wood debris begins –

17 Pb-210, Cs-137, T. Hg, T. Pb, TOC 7 – 1 Light brown fine silt and clay –

18 Archive – – 1 Light brown fine silt and clay –

19 Pb-210, T. Hg, T. Pb, TOC 8 41-8541 1 Light brown fine silt and clay –

20 Pb-210, T. Hg, T. Pb, TOC 8 – 1 Light brown fine silt and clay –

21 Archive – – 1 Light brown fine silt and clay –

22 Pb-210, Cs-137, T. Hg, T. Pb, TOC 9 41-8542 1 Light brown fine silt and clay –

23 Pb-210, Cs-137, T. Hg, T. Pb, TOC 9 – 1 Light brown fine silt and clay –

24 Archive – – 2 Light brown fine silt and clay –

25 Pb-210, T. Hg, T. Pb, TOC 10 41-8543 2 Light brown fine silt and clay –

Table D1. Sediment core logs for lakes in Whatcom County, Washington—Continued

[Analysis: Pb-210, lead-210; Cs-137, cesium-137; T. Hg, total mercury; T. Pb, total lead; TOC, total organic carbon. Analytical sample No.:

Sample in core sent out for analysis. Up to two sections may have been combined to form an analytical sample. cm, centimeter. –, no data]

Section Analysis

Analytical 

sample 

No.

Ecology 

sample

No.

Length 

(cm) Description Notes

Appendix D 85 
Table D2. Summary of analysis of sediment cores from lakes in Whatcom County, Washington, September 2002

[<, not detected at detection limit shown (detection limit varied because of the mass of sediment used in the analyses); J, estimated value 

because holding time elapsed; J2, disregarded—used 19 percent for 2-3 cm section and 25 percent for 5-6 cm section. mg/kg, dw, milligrams 

per kilograms, dry weight; piC/g, picocurie per gram. – no data]

Lake Collection 

date

Ecology 

sample 

No.

Interval 

(cm)

Percentage of 

solids

Total organic 

carbon 

(percentage by 

weight)

Total 

mercury 

(mg/kg, dw)

Total lead 

(mg/kg, dw)

 Lead-210

(piC/g)

Cesium137

(piC/g)

Lake Samish 09/23/02 02408577 0-1 14.1 5.7 0.13 36.8 10.4 2.44

02408578 1-2 51.3J2 5.5 .19 42.4 1.6 –

02408579 3-5 7.9J2 4.9 .166 45.6 5.42 1.45

02408580 6-8 29.2 4.7 .178 62.8 5.25 1.91

02408581 9-11 29.7 5.1 .142 36.5 <1.32 –

02408582 12-14 22.7 6.3 .112 35.4 <.95 <.18

02408583 15-17 21.3 6.6 .161 32.5 <2.56 –

02408584 18-20 19.3 7.1 .12 17.8 <.93 <-.29

02408585 22-24 17.9 7.1 .11 8.06 <3.65 –

02408586 27-31 19.9 6.6 .088 6.1 <.89 –

Lake Terrell 09/24/02 02418566 0-1 8.8 19.4 .16J 89.8 <2.67 <3.37

02418567 1-2 8.6 2.6 .15J 57.9 7.74 –

02418568 3-5 1.2 2.4 .2J 9.5 8.25 2.97

02418569 5-7 8.2 21.0 .21J 89.6 5.33 3.23

02418570 7-9 11.2 25.1 .21J 91.4 5.92 –

02418571 9-11 1.5 25.0 .2J 86 4.96 –

02418572 12-14 9.1 33.0 .22J 74 4.42 1.45

02418573 15-17 12.8 24.8 .14J 3.3 <1.49 –

02418574 18-21 2.2 15.9 .095J 17.4 <.96 <.15

02418575 23-25 17.7 17.6 .079J 6.63 2.73 –

Wiser Lake 09/24/02 02418544 0-1 11.1 18.0 .23J 54.5 5.12 <.66

02418545 1-2 1.0 18.2 J .16J 48.1 5.53 –

02418546 3-5 1.0 18.5 .403J 49.8 <3.15 <.17

02418547 7-9 1.6 18.0 .13J 5.3 6.48 <.99

02418548 11-13 9.3 2.0 .16J 67.6 <4.57 –

02418549 14-16 8.9 18.9 .372J 66 2.83 <.73

02418550 20-23 11.0 2.9 .14J 26 <.62 <.78

02418551 26-29 1.1 21.6 .33J 16.4 <1.39 –

02418552 32-35 1.8 23.6 .367 8.71 <1.26 –

02418553 40-44 11.8 21.6 .23J 2.55 <.43 –

Fazon Lake 09/24/02 02418555 0-1 7.3 25.5 .18J 48.6 5.02 <2.56

02418556 1-2 7.2 27.0 .27J 38.3 5.8 –

02418557 3-5 6.9 27.3 .26J 43.4 3.99 <1.99

02418558 7-9 8.1 24.3 .26J 54.8 8.48 2.39

02418559 11-13 7.9 26.8 .23J 88.2 5.97 –

02418560 15-18 9.0 25.0 .24J 56.7 4.99 3.33

02418561 21-24 9.6 24.1 .26J 58.7 5.34 3.11

02418562 27-30 11.1 22.2 .22J 47.1 3.37 –

02418563 33-36 9.3 26.1 .21J 29.2 2.22 –

02418564 40-44 7.9 27.7 .14J 13.3 3.44 –

Baker Lake 09/26/02 02418534 0-1 3.2 2.5 .056 37.4 3.11 <.73

02418535 1-2 39.2 1.8 .057 31.1 4.33 –

02418536 3-5 38.6 2.3 .065 37 6.29 .97

02418537 6-8 43.3 2.1 .0728 37.5 4.2 1.47

02418538 9-11 45.1 2.0 .0762 43.2 6.05 2.29

02418539 12-14 48.5 1.5 .0636 31.7 4.75 –

02418540 15-17 43.7 2.4 J .166 32 2.56 2.81

02418541 18-20 39.8 2.8 .105 39.7 <5.17 –

02418542 21-23 46.9 2.0 .121J 3.5 5.03

02418543 25-27 47.5 .2 .1 J 27.3 <2.08 –

86 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Table D3. Estimates of mass sedimentation rates based on anayses of sediment cores from lakes in Whatcom County, Washington

[All values are in grams per square centimeter per year. Values in bold are assigned a high weighting factor; Values in italic are assigned a 

moderage weighting factor; Values underlined are assigned a low weighting factor]

Lake Lead-210 

slope

Lead peak Cesium-137 Weight of 

evidence Peak Appearance Matching Peak Appearance

Lake Whatcom

Basin 1 avg. 0.046 0.034 – 0.045 0.050 – 0.045

min – .018 .035 – .032 0.045 –

max – .074 .068 – .072 .062 –

Basin 2 avg. .105 – – .040 .023 – .040

min – – .039 – .016 .047 –

max – .059 .063 – .051 .079 –

Basin 3 avg. .034 – – .052 – – .040

 min – – – – – – –

max .080 .074 – – – – –

Lake Samish avg. – .072 – – – – .072

min – .046 .056 – – .046 –

max – .085 .082 – – .067 –

LakeTerrell avg. .095 .029 – .025 .029 – .031

min – – .038 – – .031 –

max – .046 .054 – .047 .048 –

Wiser Lake avg. – .049 – .040 – – .049

min – .041 .049 – – – –

max – .079 .074 – – – –

Fazon Lake avg. .044 .035 – .039 .039 – .039

min – .029 .051 – .022 – –

max – .045 – – – – –

Baker Lake avg. – – – – – – –

min – – – – .370 – .370

max – – – – – – –

Appendix D 87 
Table D4. Estimated rates of sedimentation in Lake Whatcom, Washington, after adjusting for focusing factor obtained from lead-210 inventories 

of sediment cores

[(g/cm2)/yr, grams per cubic centimeter per year; cm, centimeters; (pCi/cm2)/yr, picocuries per cubic centimeter per year; Mg/yr, megagrams per year]

Lake Whatcom

Core 

sedimentation 

rate 

[(g/cm2)/yr]

Lead-210 

inventory

(pCi/cm2)

Depth of 

inventory

(cm)

Lead-210 

steady state 

flux

[(pCi/cm2)/yr]

Estimated 

focusing 

factor

Estimated 

average basin 

sedimentation 

rate

[(g/cm2)yr]

Estimated basin 

sedimentation 

(Mg/yr)

Basin 1 0.045 52.6 10 1.63 10.6 0.0042 89

Basin 2 .040 58.3 13 1.81 11.7 .0034 55

Basin 3 .040 30.0 11 .93 6.04 .0066 1,099

 Total........................................................................................................................ 1,243

88 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure D2. Summary of sedimentation rates estimated from analyses of sediment cores from Lake Whatcom, Washington. 

The upper error estimates for sedimentation rates calculated from 210Pb core from basin 3 was calculated by including the detectable 210Pb concentration from the 10-12 cm section. The minimum thickness of the core section in which the peak or first appearance of 

elevated stable Pb or 137Cs could have occurred determined the range of sedimentation rates (error bars).

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Figure D3. Characteristics of sediment core from Basin 2 of Lake Whatcom, Washington.

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Figure D4. Characteristics of sediment core from Basin 3 of Lake Whatcom, Washington.

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Figure D5. Characteristics of sediment core from Samish Lake, Washington.

Appendix D 93 
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Figure D6. Summary of sedimentation rates estimated from analysis of sediment cores from Lake Samish, Lake Terrell, Wiser Lake and 

Fazon Lake. The minimum thickness of the core section in which the peak or first appearance of 137Cs and elevated stable Pb could have

occurred determined the range of sedimentation rates (error bars).

94 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure D7. Characteristics of sediment core from Terrell Lake, Washington.

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Figure D8. Characteristics of sediment core from Wiser Lake, Washington.

96 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
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Figure D9. Characteristics of sediment core from Fazon Lake, Washington.

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Figure D10. Characteristics of sediment core from Baker Lake, Washington.

98 Sources of Mercury in Sediments, Water, and Fish of the Lakes of Whatcom County, Washington 
Manuscript approved for publication, May 24, 2004

Prepared by the Publishing Group, U.S. Geological Survey, 

Washington Water Science Center, Tacoma, Washington

USGS Publishing staff

Chester Zenone

Bill Gibbs 

Bob Crist

Linda Rogers

David Holter

Bobbie Jo Richey

For more information concerning the research in this report, contact 

the Washington Water Science Center Director, 

U.S. Geological Survey,1201 Pacific Avenue – Suite 600 

Tacoma, Washington 98402

http://wa.water.usgs.gov
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