Prepared in cooperation with the Department of the Navy 

Naval Facilities Engineering Command, Northwest 

Sources and Sinks of Filtered Total Mercury and 

Concentrations of Total Mercury of Solids and of Filtered 

Methylmercury, Sinclair Inlet, Kitsap County, Washington, 

2007–10

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5223

Sources and Sinks of Filtered Total 

Mercury and Concentrations of Total 

Mercury of Solids and of Filtered 

Methylmercury, Sinclair Inlet, Kitsap 

County, Washington, 2007–10

By Anthony J. Paulson, Richard S. Dinicola, Marlene A. Noble, Richard J. 

Wagner, Raegan L. Huffman, Patrick W. Moran, and John F. DeWild 

Prepared in cooperation with Department of the Navy

Naval Facilities Engineering Command, Northwest

Scientific Investigations Report 2012-5223

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

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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., Dinicola, R.S., Noble, M.A., Wagner, R.J., Huffman, R.L., Moran, P.W., and DeWild, J.F., 2012, Sources 

and sinks of filtered total mercury and concentrations of total mercury of solids and of filtered methylmercury, Sinclair 

Inlet, Kitsap County, Washington, 2007–10: U.S. Geological Survey Scientific Investigations Report 2012-5223, 94 p.
iii

Contents

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

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

Purpose and Scope of Watershed Project.......................................................................................2

Study Area.......................................................................................................................................................3

Sinclair Inlet...........................................................................................................................................3

Bremerton Naval Complex ..................................................................................................................3

Zone of Direct Discharge ...........................................................................................................7

Vicinity of Site 2............................................................................................................................7

Capture Zone of Sumps ..............................................................................................................7

History of Remediation and Environmental Investigations Related to Mercury ...............................10

Synthesis of Existing Data..........................................................................................................................11

Puget Sound Sources ........................................................................................................................11

Atmospheric Deposition ....................................................................................................................12

Total Mercury .............................................................................................................................12

Methylmercury ..........................................................................................................................12

Sources Discharging into Greater Sinclair Inlet ...........................................................................12

Creeks Discharging to Greater Sinclair Inlet ........................................................................12

Greater Sinclair Inlet Stormwater...........................................................................................13

Municipal Wastewater Treatment Plant Effluent .................................................................13

Bremerton Naval Complex ................................................................................................................13

Stormwater Discharged from Bremerton Naval Complex..................................................13

Zone of Direct Discharge ................................................................................................13

Vicinity of Site 2.................................................................................................................13

Capture Zone of Sumps ...................................................................................................14

Groundwater in Bremerton Naval Complex ..........................................................................14

Zone of Direct Discharge ................................................................................................14

Vicinity of Site 2.................................................................................................................14

Capture Zone of Sumps ...................................................................................................15

Methods for USGS Sampling .....................................................................................................................15

Sampling...............................................................................................................................................15

Creeks .........................................................................................................................................15

Stormwater.................................................................................................................................15

Municipal Effluents....................................................................................................................16

Bremerton Naval Complex Industrial Discharges................................................................16

Groundwater...............................................................................................................................17

Base-Wide Sampling .......................................................................................................17

Tidal Studies.......................................................................................................................17

Laboratory Processing.......................................................................................................................18
iv

Contents—Continued

Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet......................................18

Mass Balance of Water and Salt.....................................................................................................18

Sources of Freshwater .............................................................................................................18

Atmospheric Deposition ..................................................................................................19

Freshwater Discharging to Greater Sinclair Inlet .......................................................19

Freshwater Sources from Bremerton Naval Complex ...............................................21

Net Advective Transport across the Seaward Boundary ...................................................22

Mass Balance of Solids.....................................................................................................................25

Sources of Solids.......................................................................................................................25

Puget Sound Sources of Solids......................................................................................26

Solids Discharging into Greater Sinclair Inlet .............................................................26

Solids Discharging from Bremerton Naval Complex ..................................................26

Sinks for Solids...........................................................................................................................27

Rationale for Separate Mass Balances of Dissolved and Particulate Mercury in Sinclair Inlet...28

Sources and Sinks of Filtered Total Mercury to Sinclair Inlet..............................................................29

Concentrations of Filtered Total Mercury.......................................................................................29

Seawater Transported to Puget Sound...........................................................................................29

Water Discharged to Greater Sinclair Inlet....................................................................................29

Creek Basins...............................................................................................................................29

Stormwater.................................................................................................................................31

Wastewater Treatment Plant Effluents ..................................................................................31

Water Discharged from the Bremerton Naval Complex ..............................................................31

Zone of Direct Discharge ................................................................................................31

Vicinity of Site 2.................................................................................................................32

May 6, 2008 Tidal Study...........................................................................................33

June 4–5, 2008 Tidal Study .....................................................................................35

Mercury in the Stormwater Drain PSNS015 .........................................................................36

Capture Zone of Sumps ...................................................................................................37

Porewater of Sinclair Inlet Sediment ..............................................................................................40

Synthesis of Loadings of Filtered Total Mercury to Sinclair Inlet...............................................40

Exchange between Sinclair Inlet and Puget Sound ............................................................40

Direct Atmospheric Deposition ..............................................................................................42

Loads Discharged to Greater Sinclair Inlet ..........................................................................42

Creeks ................................................................................................................................42

Stormwater........................................................................................................................42

Municipal Effluent.............................................................................................................43
v

Contents—Continued

Sources and Sinks of Filtered Total Mercury to Sinclair Inlet—Continued

Synthesis of Loadings of Filtered Total Mercury to Sinclair Inlet—Continued

Loadings from Bremerton Naval Complex.............................................................................43

Zone of Direct Discharge ................................................................................................43

Vicinity of Site 2.................................................................................................................43

Groundwater.............................................................................................................43

Discharge through PSNS015 Stormwater Drain ................................................44

Capture Zone of Sumps ..................................................................................................48

Marine Sedimentary Sources..................................................................................................49

Ranking of Sources of Filtered Total Mercury to Sinclair Inlet..........................................49

Concentrations of Total Mercury of Solids Discharged to Sinclair Inlet............................................50

Solids Discharged to Greater Sinclair Inlet....................................................................................50

Creek .........................................................................................................................................50

Stormwater Basins....................................................................................................................50

Wastewater Effluents................................................................................................................50

Solids Discharged from the Bremerton Naval Complex ..............................................................50

Zone of Direct Discharge .........................................................................................................50

Vicinity of Site 2..........................................................................................................................50

Capture Zone of the Sumps......................................................................................................52

Synthesis of Concentrations of Total Mercury of Solids Discharged to Sinclair Inlet ...........52

Methylmercury in the Sinclair Inlet Drainage Basin .............................................................................56

Greater Sinclair Inlet.................................................................................................................56

Bremerton Naval Complex ......................................................................................................57

Sinclair Inlet Sediment..............................................................................................................58

Synthesis of Methylmercury in Sinclair Inlet.................................................................................58

Observations Indicating the Need for Further Study.............................................................................58

Groundwater........................................................................................................................................58

Industrial Sources...............................................................................................................................59

Streams.................................................................................................................................................59

Summary .......................................................................................................................................................59

Acknowledgments.......................................................................................................................................60

References Cited..........................................................................................................................................60

Appendix A. Data From U.S. Navy and Environmental Investment Projects ....................................65

Appendix B. Calculation of Sedimentation of Solids in Sinclair Inlet .................................................83

Appendix C. Calculation of Total Mercury Concentrations of Solids ..................................................89
vi

Figures

Figure 1. Map showing locations of Sinclair and Dyes Inlets selected marine

water-quality stations in central Puget Sound, and stormwater stations 

outside of Sinclair Inlet, Washington ................................................... 4

Figure 2. Map showing location of the U.S. Navy Long-Term Monitoring Program cells 

in the sediment-sampling grid, stormwater sites sampled by ENVironmental

inVESTment project, marine station of the Washington Department of Ecology

and USGS acoustic Doppler current profiler site, Sinclair Inlet, Kitsap County,

Washington ................................................................................. 5

Figure 3. Map showing Bremerton naval complex along the northern shore of Sinclair

Inlet, Kitsap County, Washington ......................................................... 6

Figure 4. Map showing locations of well and stormwater drain sampling sites in the

Bremerton naval complex, stream and stormwater sampling sites, and marine

water column stations sampled by USGS between December 2007 and March

2010, Sinclair Inlet, Kitsap County, Washington ....................................... 8

Figure 5. Schematic diagram and photograph showing the Vicinity Site 2 of the Initial

Assessment Study including boreholes and decommissioned monitoring wells,

Operable Unit B Terrestrial (OUBT) wells OUBT-722 and 718, and vaults of the

PSNS015 storm water system sampled by U.S. Geological Survey, Bremerton

naval complex, Bremerton, Washington, 2009–10 .................................... 9

Figure 6. Diagram showing flow of freshwater, seawater recycled into and out of

Bremerton naval complex, and net advective transfers between Sinclair Inlet 

and Puget Sound, Kitsap County, Washington .......................................... 21

Figure 7. Graphs showing profiles of current with depth at the CENTER and WEST 

acoustic Doppler current profiler sites during late winter and summer 1994, 

Sinclair Inlet, Washington .................................................................. 24

Figure 8. Graph showing concentrations of filtered total mercury in near-surface water

collected from four stations in Sinclair Inlet, August 2008– August 2009 ............ 28

Figure 9. Graph showing filtered and particulate total mercury relative to specific

conductance in the effluent from the steam plant, Bremerton naval complex,

Kitsap County, Washington ............................................................... 33

Figure 10. Graphs showing water levels, total mercury concentrations of filtered water, 

and salinity in well OUBT-722 during the May 6, 2008 tidal study ..................... 34

Figure 11. Graphs showing concentrations of total mercury in filtered water, water levels,

and salinity in OUBT-722 during the during the June 4–5, 2008 tidal study,

Bremerton naval complex, Kitsap County, Washington................................. 35
vii

Figures—Continued

Figure 12. Graph showing water levels and salinity in stormwater drain PSNS015 during 

the latter part of the morning ebbing tide on March 31, 2010, Kitsap County,

Washington ................................................................................. 38

Figure 13. Graph showing flow, filtered total mercury, and salinity in the PSNS015

stormwater drain on the Bremerton naval complex during the morning ebbing

tidal cycle of March 31, 2010, Kitsap County, Washington ........................... 39

Figure 14. Diagram of loadings of filtered total mecury from freshwater sources, from

seawater recycled in and out of Bremerton naval complex, and from net

advective transfers between Sinclair Inlet and Puget Sound, Washington ......... 41

Figure 15. Diagrams of extraction of Site 2 soils by seawater leaking from and flowing to

PSNS015 stormwater drain system on the Bremerton naval complex, Kitsap

County, Washington ........................................................................ 45

Figure 16. Diagrams of episodic releases of filtered total mercury during certain tidal

conditions .................................................................................... 47

Figure 17. Graph showing concentrations of total mercury of suspended solids in streams,

stormwater, and wastewater treatment plants in the Sinclair Inlet basin, Kitsap

County, Washington measured by USGS (2008–09), maximum concentrations

calculated from ENVVEST data (2002–05), and concentrations in solids

suspended in the upper layer of greater Sinclair Inlet ................................. 51

Figure 18. Graph showing concentrations of total mercury of solids originating from

Bremerton naval complex, Kitsap County, Washington................................. 51

Figure 19. Graph showing cumulative probability distribution of total mercury

concentrations of solids suspended in the upper layer of the water column, 

of surface sediment (2003–07) and of surface sediment (2010) from greater 

Sinclair Inlet, Kitsap County, Washington ................................................ 54

Figure 20. Graph showing cumulative probability distribution of concentrations of total

mercury of solids suspended in the upper layer of the marine water column

(2008–09) and total mercury in sediment collected between 2003 and 2007, and 

in 2010 from OU B Marine of the Bremerton naval complex, Kitsap County,

Washington ................................................................................. 55

Figure 21. Graph showing methylmercury concentrations in terrestrial sources within 

the Bremerton naval complex and from basins of greater Sinclair Inlet, Kitsap 

County, Washington ........................................................................ 56
viii

Tables

Table 1. Differences in salinity between upper and lower layers from selected sites,

Sinclair Inlet, Kitsap County, Washington ................................................ 19

Table 2. Freshwater discharge, freshwater yields, and loadings of suspended solids 

to and from Sinclair Inlet, Kitsap County, Washington ................................. 20

Table 3. Total suspended solids, filtered total mercury, and total mercury of suspended

solids from five categories of the marine water samples from Sinclair Inlet, 

Kitsap County, Washington, 2008–09 ...................................................... 27

Table 4. Concentrations and loadings of filtered total mercury for Sinclair Inlet, Kitsap

County, Washington. ........................................................................ 30

Table 5. Frequency of filtered mercury concentrations greater than 10 nanograms 

per liter in samples from the Bremerton naval complex, Kitsap County, 

Washington ................................................................................. 32

Table 6. Summary total mercury and methylmercury concentrations in filtered water,

salinity, and particulate total mercury from five piezometers installed in the

intertidal zone seaward of well OUBT-722, Bremerton naval complex, Kitsap

County, Washington ........................................................................ 36

Table 7. Concentrations of filtered total mercury in porewater of sediment and fluxes 

of filtered total mercury from sediment in Sinclair Inlet, Kitsap County, 

Washington between August 2008 and August 2009.................................... 40

Table 8. Possible sources of filtered total mercury discharged by the dry dock relief

drainage systems, Bremerton naval complex, Kitsap County, Washington ......... 48

Table 9. Non-parametric correlation statistics of filtered methylmercury concentrations

relative to concentrations of reduced biogeochemicals .............................. 57

Table 10. Concentrations of filtered methylmercury in porewaters from three stations 

in the Bremerton naval complex and three stations in greater Sinclair Inlet, 

Kitsap County, Washington, August 2008–August 2009 ................................. 58
ix

Conversion Factors, Datums, and Abbreviations and 

Acronyms

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

inch (in.) 2.54 centimeter (cm)

SI to Inch/Pound

Multiply By To obtain

Length

micrometer (μm) 0.003937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

centimeter (cm) 0.3937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square kilometer (km2) 247.1 acre

square meter (m2) 10.76 square foot (ft2) 

square kilometer (km2) 0.3861 square mile (mi2)

Volume

milliliter (mL) 0.0338 ounce, fluid (fl. oz)

cubic meter (m3) 0.0002642 million gallons (Mgal) 

cubic meter (m3) 0.0008107 acre-foot (acre-ft) 

liter (L) 1.057 quart (qt)

liter (L) 0.2642 gallon (gal)

Flow rate

milliliter per minute (mL/min) 5.8857 cubic foot per second (ft3/s)

cubic meter per second (m3/s) 70.07 acre-foot per day (acre-ft/d) 

liter per second (L/s) 15.85 gallon per minute (gal/min) 

Mass

gram 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton per year 1.102 ton per year (ton/yr)

Sedimentation rate

gram per square centimeter (g cm-2) 0.228 ounce per square inch (oz/in2)
x

Conversion Factors, Datums, and Abbreviations and 

Acronyms—Continued

Conversion Factors—Continued

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

°F=(1.8×°C)+32.

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

°C=(°F-32)/1.8.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L), 

micrograms per liter (μg/L), or nanograms per liter (ng/L).

Concentrations of chemical constituents of solids are given in either percentage of dry weight, 

milligrams per kilogram (mg/kg) or nanograms per milligram (ng/mg), which are equivalent.

Datums

Vertical coordinate information is referenced to the North American Vertical Datum of 29 (NAVD 

29). The vertical datum mean lower low water (MLLW) is defined as -1.83 m relative to NAVD 29.

Horizontal coordinate information is referenced to North American Datum of 1988 (NAD 88).

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

Abbreviations and Acronyms

ADCP acoustic Doppler current profiler

BNC Bremerton naval complex

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CH3D Curvilinear Hydrodynamics in 3-Dimensions

CSO Combined sewer overflow

CTD conductivity temperature depth 

DOC dissolved organic carbon

ENVVEST ENVironmental inVESTment 

FFW volume fraction of freshwater

FSW volume fraction of seawater

FC fecal coliform

FMHg filtered methylmercury

FTHg filtered total mercury

HDPE high-density polyethylene

HSPF Hydrologic Simulation Program - FORTRAN

IAS Initial Assessment Study

LMK Label used by Kitsap County, Washington

LTMP Long-term Monitoring Program

MHg methylmercury

MLLW mean lower low water

MW monitoring well
xi

NBK Bremerton Naval Base Kitsap at Bremerton

NPDES National Pollutant Discharge Elimination System

NWQL National Water Quality Laboratory

OU Operable unit

OU NSC Operable Unit Naval Supply Center

OUBT Operable Unit B Terrestrial

PAHs polyaromatic hydrocarbons

210Pb isotope of lead having a atomic weight of 210

PBDEs Polybrominated diphenyl esters

PCBs polychlorinated biphenyls

PDT Pacific Daylight Savings Time

PETG polyethylene terephthalate copolyester

PFA Perfluoroalkoxy

PN particulate nitrogen

PO Port Orchard

PO-BLVD Port Orchard Boulevard

POC particulate organic carbon

PS02 Site 2 of the Preliminary Assessment

PSNS Puget Sound Naval Shipyard

PSNS&IMF Puget Sound Naval Shipyard and Intermediate Maintenance Facility

PSS Practical salinity scale (unitless)

PTFE Polytetrafluoroethylene 

PTHg particulate total mercury

PVC polyvinyl chloride

QFF quartz fiber filter

QFW discharge of freshwater into Sinclair Inlet

QSW transport of central Puget Sound seawater into Sinclair Inlet

RI/FS Revisit Remedial Investigation/Feasibility Study

ROD Record of Decision

RPD Relative percent difference

SSI salinity of Sinclair Inlet

SDD salinity of dry dock discharge

SLL salinity of lower layer

SUL salinity of upper layer

SI Sinclair Inlet

SPAWAR The Space and Naval Warfare Systems Command

STHg total mercury concentration of sediment

THg total mercury

TSS total suspended solids

WAWSC Washington Water Science Center

WMRL Wisconsin Mercury Research Laboratory

WTHg total mercury in whole (unfiltered) water

Conversion Factors, Datums, and Abbreviations and 

Acronyms—Continued

Abbreviations and Acronyms—Continued
xii

This page intentionally blank.
Sources and Sinks of Filtered Total Mercury and 

Concentrations of Total Mercury of Solids and of 

Filtered Methylmercury, Sinclair Inlet, Kitsap County, 

Washington, 2007–10

By Anthony J. Paulson, Richard S. Dinicola, Marlene A. Noble, Richard J. Wagner, Raegan L. Huffman, 

Patrick W. Moran, and John F. DeWild 

Abstract

The majority of filtered total mercury in the marine 

water of Sinclair Inlet originates from salt water flowing from 

Puget Sound. About 420 grams of filtered total mercury are 

added to Sinclair Inlet each year from atmospheric, terrestrial, 

and sedimentary sources, which has increased filtered total 

mercury concentrations in Sinclair Inlet (0.33 nanograms 

per liter) to concentrations greater than those of the Puget 

Sound (0.2 nanograms per liter). The category with the largest 

loading of filtered total mercury to Sinclair Inlet included 

diffusion of porewaters from marine sediment to the water 

column of Sinclair Inlet and discharge through the largest 

stormwater drain on the Bremerton naval complex, Bremerton, 

Washington. However, few data are available to estimate 

porewater and stormwater releases with any certainty. The 

release from the stormwater drain does not originate from 

overland flow of stormwater. Rather total mercury on soils is 

extracted by the chloride ions in seawater as the stormwater 

is drained and adjacent soils are flushed with seawater by 

tidal pumping. Filtered total mercury released by an unknown 

freshwater mechanism also was observed in the stormwater 

flowing through this drain. 

Direct atmospheric deposition on the Sinclair Inlet, 

freshwater discharge from creek and stormwater basins 

draining into Sinclair Inlet, and saline discharges from the 

dry dock sumps of the naval complex are included in the next 

largest loading category of sources of filtered total mercury. 

Individual discharges from a municipal wastewater treatment 

plant and from the industrial steam plant of the naval complex 

constituted the loading category with the third largest 

loadings. Stormwater discharge from the shipyard portion of 

the naval complex and groundwater discharge from the base 

are included in the loading category with the smallest loading 

of filtered total mercury. 

Presently, the origins of the solids depositing to the 

sediment of Sinclair Inlet are uncertain, and consequently, 

concentrations of sediments can be qualitatively compared 

only to total mercury concentrations of solids suspended in the 

water column. Concentrations of total mercury of suspended 

solids from creeks, stormwater, and even wastewater effluent 

discharging into greater Sinclair Inlet were comparable to 

concentrations of solids suspended in the water column of 

Sinclair Inlet. Concentrations of total mercury of suspended 

solids were significantly lower than those of marine bed 

sediment of Sinclair Inlet; these suspended solids have been 

shown to settle in Sinclair Inlet. The settling of suspended 

solids in the greater Sinclair Inlet and in Operable Unit 

B Marine of the naval complex likely will result in lower 

concentrations of total mercury in sediments. Such a decrease 

in total mercury concentrations was observed in the sediment 

of Operable Unit B Marine in 2010. However, total mercury 

concentrations of solids discharged from several sources from 

the Bremerton naval complex were higher than concentrations 

in sediment collected from Operable Unit B Marine. The 

combined loading of solids from these sources is small 

compared to the amount of solids depositing in OU B Marine. 

However, total mercury concentration in sediment collected 

at a monitoring station just offshore one of these sources, the 

largest stormwater drain on the Bremerton naval complex, 

increased considerably in 2010.

Low methylmercury concentrations were detected in 

groundwater, stormwater, and effluents discharged from 

the Bremerton naval complex. The highest methylmercury 

concentrations were measured in the porewaters of highly 

reducing marine sediment in greater Sinclair Inlet. The marine 

sediment collected off the largest stormwater drain contained 

low concentrations of methylmercury in porewater because 

these sediments were not highly reducing.
2 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Introduction

In the 1980s, the sediment of Sinclair Inlet was known 

to have elevated concentrations of a number of elements and 

organic compounds (Malins and others, 1982). A remedial 

investigation of the marine waters off the Bremerton naval 

complex (BNC), Bremerton, Washington, was completed 

under the Comprehensive Environmental Response, 

Compensation, and Liability Act (CERCLA) in 1996 

(U.S. Navy, 2002) and the final Record of Decision (U.S. 

Environmental Protection Agency, 2000) was issued in 2000. 

The remediation options included isolating a considerable 

volume of contaminated sediment from interactions with the 

benthic food web by placing dredge spoils from navigational 

and cleanup dredging in a covered confined aquatic disposal 

pit created in 2001. The primary objective of the marine 

sediment cleanup was to address the potential risk to humans, 

particularly those engaged in a subsistence lifestyle, from 

consumption of bottom-dwelling fish with tissue containing 

elevated concentrations of polychlorinated biphenyls (PCBs) 

(U.S. Navy, 2002). Three pathways were identified as 

having the capability to transport chemicals from terrestrial 

landscape of the BNC to the marine environment, thus have 

the potential to recontaminate recently remediated marine 

sediment. The pathways included discharges from dry dock, 

groundwater, and stormwater system facilities that handle 

surface-water runoff. 

As lead agency for environmental cleanup of the BNC, 

the U.S. Navy completed a second 5-year review of the 

remedial actions for marine sediment within the boundary of 

the BNC (U.S. Navy, 2008a), pursuant to Section 121(c) of 

CERCLA and the National Oil and Hazardous Substances 

Pollution Contingency Plan (40 Code of Federal Regulations 

Part 300). One issue highlighted in the second 5-year review 

was, “There is insufficient information to determine whether 

the remedial action taken at OU [Operable Unit] B Marine 

with respect to mercury in sediment is protective of ingestion 

of rockfish by subsistence finfishers,” (U.S Navy, 2008a, 

p. 5). Recommendations and follow-up actions in the 5-year 

review were:

• Revisit Remedial Investigation/Feasibility Study 

(RI/FS) groundwater-to-surface-water transport 

evaluations considering total mercury concentrations 

in two long-term monitoring wells, 

• Perform trend analyses and assess functionality and 

protectiveness of remedy for marine sediment, and

• Collect additional information necessary to perform 

a risk evaluation and reach conclusions regarding the 

protectiveness of the remedy (U.S. Navy, 2002) with 

respect to total mercury concentrations in Sinclair Inlet 

sediment and fish tissue.

Since 2007, the U.S. Geological Survey (USGS) and the 

U.S. Navy have entered into several multiyear interagency 

agreements, the Watershed Project and the Methylation and 

Bioaccumulation Project (http://wa.water.usgs.gov/projects/

sinclair/). The objective of the Watershed Project is to estimate 

the magnitudes of the predominant sources of total mercury to 

Sinclair Inlet, including those from the BNC. The objectives 

of the companion Methylation and Bioaccumulation Project 

is to evaluate the transformation of mercury to a bioavailable 

form in Sinclair Inlet and to assess the effect of the sources 

and transformation processes on the mercury burden in 

marine organisms and sediment. In this report, total mercury 

(THg) refers to all chemical forms of mercury (including 

methylmercury [MHg]), and not to an unfiltered water sample. 

A listing of published documents on mercury in Sinclair 

Inlet is available at http://wa.water.usgs.gov/projects/sinclair/

publications.htm.

Purpose and Scope of Watershed Project

The Watershed Project focused on the first objective of 

estimating the magnitudes of the predominant sources of THg 

to Sinclair Inlet. To accomplish this objective, the USGS: 

(1) examined the status of THg in the sediment, water, and 

biota of Sinclair Inlet using data available at the beginning 

of the study (2007); (2) assessed the sources of THg to 

Sinclair Inlet; (3) generated new data used to evaluate sources 

of THg from permitted sources and groundwater flowing 

from the BNC into Sinclair Inlet; and (4) made of the first 

measurements of MHg in the Sinclair Inlet basin.

Data for THg in sediment, water, and biota of Sinclair 

Inlet from other sources available at the beginning of the 

project were reported in Paulson and others (2010). This report 

describes the assessment of sources of THg to Sinclair Inlet 

using new data and presents the results from the first survey 

and measurements of MHg concentrations in the aqueous 

phase in sources of water discharging to Sinclair Inlet. Sources 

of THg from BNC groundwater, stormwater drains, and 

industrial sources were assessed using the new data. Where 

possible, the sources of THg in the aqueous and particulate 

forms from the BNC were compared to other sources of 

THg into Sinclair Inlet. The sources of THg from the BNC 

were compared to other sources including advection from 

Puget Sound, direct precipitation on the surface of Sinclair 

Inlet, creeks draining into Sinclair Inlet, and diffusive flux of 

aqueous THg from Sinclair Inlet sediment. Not all sources 

of mercury were examined in the same detail; therefore, the 

overall conclusions are limited to ranking the overall effect of 

the various sources that were examined. Where appropriate, 

this report draws on new mercury data from the water 

and sediment samples collected as part of the companion 

Methylation and Bioaccumulation Project. 
Study Area 3

Study Area

Sinclair Inlet

Sinclair Inlet is a shallow (maximum depth of 20 m) 

embayment on the west side of the Puget Sound lowland 

(fig. 1). The major axis of the inlet is aligned about 65 degrees 

clockwise of north (along 65 degrees true). The Puget Sound 

lowland is a long, northward-trending structural depression 

situated. Most of the Puget Sound lowland physiographic 

province is mantled with thick glacial and postglacial deposits. 

Sinclair Inlet is adjacent to Dyes Inlet, another shallow 

embayment (fig. 1). The Dyes Inlet-Sinclair Inlet system is 

hydraulically complex not only because of the geometry of 

the connection, but because Bainbridge Island constricts this 

connection between the Dyes Inlet-Sinclair Inlet system and 

central Puget Sound. The Dyes Inlet-Sinclair Inlet system is 

connected to central Puget Sound through a convergence zone 

in which water flows through Port Madison, and Agate and 

Port Orchard Passages on the north side of Bainbridge Island, 

and through Rich Passage on the south side of Bainbridge 

Island. Rich Passage shallows to 20 m; the maximum depth 

in Agate Passage is 6 m. The shallowness of these passages 

results in extensive vertical mixing of the incoming tidal 

water. Tides in Puget Sound are mixed diurnally and have a 

maximum tidal range of about 5 m relative to a maximum 

depth of about 20 m for Sinclair Inlet. The relative proportion 

of tidal volumes through Port Orchard and Rich Passages is 

unknown. Because the increase in volume of water in Dyes 

Inlet between low tide and high tide is about three times that 

of Sinclair Inlet, tidal currents in Port Washington Narrows, 

which connects Dyes Inlet to Sinclair Inlet, often lag the tidal 

currents of Sinclair Inlet (Wang and Richter, 1999).

For the purpose of mass balance calculations in this 

report, a specific volume of water (a “box”) was defined. 

The surfaces of the box of the Sinclair Inlet model for the 

mass balances include the surface of marine sediment on 

the seabed upward to mean sea level, the sea surface that 

intersects the sediment surface at the shore, and a vertical 

plane at the outer boundary of Sinclair Inlet—defined in this 

study as the seaward side of a cable area extending from the 

Bremerton dock of the Washington State Ferry System to the 

pointed shoreline near Annapolis Creek (fig. 2). Using the 

North American Vertical Datum of 1988, this definition of the 

mass balance box yields a volume of 75.7×106 m3, a surface 

area of 8.37 km2, and a cross-sectional area of 27,050 m2 at 

its entrance. 

Sinclair Inlet has been characterized as “a tidally 

dominated, non-stratified, saline body of water” (U.S. Navy, 

1992, sec. 2, p. 6) because of the vertical mixing and the 

relatively small inflow of freshwater. Gartner and others 

(1998) determined that Sinclair Inlet was non-stratified 

and isothermal in August 1994. During the wet season in 

March 1994 when surface runoff would be near its maximum, 

stratification was weak with the salinity difference between 

upper and lower layer less than 1 in 30 units on the Practical 

Salinity Scale (PSS). Other studies (Albertson and others, 

1995; Katz and others, 2004) have shown that Sinclair Inlet is 

stratified under certain conditions. Gartner and others (1998) 

determined that typical current speeds were 5–10 cm/s. Wind 

forcing caused residual currents (time-averaged currents 

filtered with a 35-hour low-pass filter) in the bottom layer 

to be in the opposite direction of the surface layer currents 

and wind direction. Unlike systems dominated by estuarine 

circulation, residual currents in Sinclair Inlet were similar in 

magnitude to the tidal currents. 

Bremerton Naval Complex

The Bremerton naval complex covers about 2 km2 on 

the north shore of Sinclair Inlet in Bremerton, Washington 

(fig. 3) and houses two Navy commands: Puget Sound 

Naval Shipyard and Intermediate Maintenance Facility 

(PSNS&IMF), Bremerton site, and Naval Base Kitsap 

at Bremerton (NBK Bremerton). The primary role of 

PSNS&IMF (1.5 km2), a fenced, high-security area, is 

to provide overhaul, maintenance, conversion, refueling, 

defueling, and repair services to the naval fleet. The primary 

role of NBK Bremerton (0.4 km2) is to serve as a deep-draft 

home port for aircraft carriers and supply ships.

For the purposes of environmental remediation, the BNC 

was divided into Operable Units (OU): OU A, OU B Marine 

and Terrestrial, OU C, OU D, and OU NSC (Naval Supply 

Center) (fig. 3). In this report, only data previously collected 

within the OU A, OU B Terrestrial and Marine, and OU NSC 

is addressed; the greater Sinclair Inlet is defined as the area in 

the box of the Sinclair Inlet model (see above) that is outside 

of OU B Marine. 

For this investigation, the BNC was divided into three 

areas defined by the flow of groundwater: (1) the Zone 

of Direct Discharge, (2) the Vicinity of Site 2, and (3) the 

Capture Zone of the Sumps associated with the dry docks 

(fig. 4). The Zone of Direct Discharge of groundwater to 

Sinclair Inlet is in the western part of BNC and includes OU A 

and the western part of NBK Bremerton (fig. 3). The Vicinity 

of Site 2 (fig. 5) is an area most affected by mercury soil 

contamination (URS Consultants, Inc., 1991) and includes the 

largest stormwater drain (PSNS015) on the base that passes 

through Site 2 and drains 0.41 km2 of the NBK Bremerton 

(fig. 3). The area of NBK Bremerton served by the stormwater 

drain contains facilities for parking, housing, shopping, 

recreation, and dining for military personnel and their families. 

Groundwater from the largest area of BNC, which includes 

OU NSC and the PSNS&IMF area of OU B Terrestrial, is 

captured by the sumps of six dry docks that are located 13 m 

below ground surface (Prych, 1997). A seawall along most of 

the shore in this area facilitates the capture of groundwater by 

the sumps. 
4 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig01

Seattle

Manchester

Bremerton

Port

Orchard

Location

figure 2

Eagle

Harbor

Dyes

Inlet

Port

Madison

Rich

Passage

Port

Washington

Narrows

Agate

Passage

ELLIOT

BAY

Port

Gardner

Port

Gamble

Sinclair Inlet

Lake Washington

Duwamish Waterway

Port Orchard

Passage

Holmes Harbor

Hood

Canal

Bainbridge

Island

Blake

Island

North

Central

Puget 

Sound

South

Puget 

Sound

South

Central

Puget 

Sound

Hood Canal

Whidbey

KSBP01

KSBP01

KSSK02

COLVOS PASS

Colvos Passage

LMK038

SHERIDAN 

ROAD

LMK038

SHERIDAN 

ROAD

USGS National Elevation Data (NED) 2000, 30 meter resolution

UTM zone 10, datum NAD83

WASHINGTON

Map

location

122°40' 122°20'

48°

47°

40'

0 2 4 6 8 10 Miles

0 2 4 6 8 10 Kilometers

EXPLANATION

King County Department 

of Natural Resources 

and Parks marine 

station

USGS stormwater 

sample

ENVVEST stormwater 

sample

Figure 1. Locations of Sinclair and Dyes Inlets, selected marine water-quality stations in central Puget Sound, and stormwater 

stations outside of Sinclair Inlet, Washington.
Study Area 5 tac11-0637_fig02

Navy ConfinedAquaticDisposal Pit 

Bremerton

Port Orchard

Gorst

Bremerton Ferry Dock

USGS National Elevation Data (NED) 2000, 30 meter resolutionUTM zone 10, datum NAD83

4

5

9

8

1

3

2

7

6

11

25

17

18

29

31

24

13

30

14

32

12

28

10

21

19

26

23

20

15

22

27

16

A

A'

B-ST28

CSO16

B-ST12

WEST

EAST

SIN001

CENTER

LMK122

PO-BLVD

Wright Creek

Ross er C ke

j kcal B ca Ck keer

nl O r Cye kee

nnA pa il o Cs er ke

Ander os n C er ke

rpS C gni

keer

Gorst Creek

S

NI

CLAIR

NI

LET

S

NI

CLAIR

NI

LET

Cable Area Seaward Boundary PUGET SOUND

0 0.5

0.5

1 Mile

0 1 Kilometer

122°36' 122°38' 122°40' 122°42'

47°34'47°32'

Current cross section trace1,500-foot grid cell boundary and cell numberBremerton naval complex boundary

OU AOU B MarineOU B TerrestrialOU COU DOther

EXPLANATION

Operable units (OU)Assumed sedimentation rate, in grams per 

cubic centimeter per year

OU Naval Supply Center

15

Contour— -5-meter Mean Lower Low Water

waterline

A A'

Fines less than 50 percent; no sedimentationFines greater than 85 percent; 

sedimentation = 0.14

Fines greater than 50 percent and less than 

85 percent; sedimentation = 0.09

Right-side color indicates areas over water.

Washington State Department of ENVVEST stormwater sample

Ecology marine station

Acoustic Doppler current profiler

PO-BLVD

CENTER

SIN001

Figure 2. Location of the U.S. Navy Long-Term Monitoring Program cells in the sediment-sampling grid, stormwater sites sampled by ENVironmental inVESTment project, 

marine station of the Washington Department of Ecology and USGS acoustic Doppler current profiler site, Sinclair Inlet, Kitsap County, Washington.
6 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig03

SINCLAIR 

INLET

4

3 8

2

6

7

5 1

9

11

67

14

43

58

68

31

57

16

10

36

32

55

28 35

21

30

26

64

53

61

52

47

25

34

19

60

46

56

50

27

42

69

37

20

51

54

29

48

65

15

23

71

41

22

18

62

44

63

66

17

70

49

40

33

12

38

59

24

45 39

13

Dry dock

Dry dock

Dry dock

Dry dock

Dry dock

Dry dock

Western

PSNS&IMF

Naval Base Kitsap

Bremerton

Operable

Unit A

Central

PSNS&IMF

Eastern

PSNS&IMF

122°40' 122°39' 122°38'

47°33'

500 1,000 Meters

00

1,000 2,000 3,000 Feet

PSNS015

LTMP-3

LTMP-1

806

410R

115.1

124

126

LTMP-5

Puget Sound Naval Shipyard PSNS

IMF

Shoreline500-foot grid cell boundary and cell numberBremerton naval complex boundary

Intermediate Maintenace Facility

OU AOU B MarineOU B TerrestrialOU COU DOther

EXPLANATION

Operable units (OU)

Fines less than 50 percent; no sedimentationFines greater than 85 percent; 

sedimentation = 0.14

Assumed sedimentation rate, in grams per 

cubic centimeter per year

Fines greater than 50 percent and less 

than 85 percent; sedimentation = 0.09

OU NSC

15

Wells sampled by U.S. NavyPSNS storm drains sampled by 

ENVVEST

806

126

Right-side color indicates areas over OU B Marine.

Locationfigure 5

Adaptation of a CAD file of Fig. 5.1 of U.S. Navy 2007b

Figure 3. Bremerton naval complex along the northern shore of Sinclair Inlet, Kitsap County, Washington.
Study Area 7

Zone of Direct Discharge

OU A consists of approximately 0.049 km2 of manmade 

land and the adjacent marine environment of Sinclair Inlet. It 

is located southwest of the main Puget Sound Naval Shipyard 

operations. The site is relatively level except for the riprap 

seawall, and most of its surface is paved. OU A is currently 

used as a parking lot for shipyard and deployed personnel and 

has been temporarily used as a staging area for dredge spoils. 

In the past, it was used as a helicopter pad and as a disposal 

area for industrial wastes associated with shipbuilding and 

decommissioning. Most of the land at OU A is composed of 

industrial fill to a depth of 2.1 to 10.7 m below the current 

ground surface. The fill increases in thickness toward the 

shore, where it is overlain with a layer of riprap stone. This 

industrial fill is composed of sandblast grit, scrap metal, 

brick, glass, wood, and other debris. Several shallow pits 

were established near the former helicopter pad and used 

for disposal of liquid wastes. OU A includes 0.003 km2 of 

impervious area and is served by two stormwater outfalls 

(U.S. Navy, 1995a). 

The Zone of Direct Discharge also includes some area in 

OU B Terrestrial including a steam plant, which is a permitted 

point source for discharge. At the time of 2008 sampling, 

municipal water was demineralized using ion exchange water 

softening technology. The effluent from the steam plant 

contained demineralizer regeneration and corrosive drain 

wastes that were neutralized and clarified through sand filters 

and gravity fed to the effluent wet well. Final pH adjustments 

were made in the wet well, if necessary, and the water was 

discharged into Sinclair Inlet. After USGS sampling ended in 

2008, a new reverse osmosis system replaced the ion exchange 

system in 2010. This upgrade in technology likely changed the 

loadings of mercury described in this report.

A concrete tank used to neutralize acids, bases, and spent 

electroplating solutions near replacement well OUBT-715R 

(fig. 4) was observed to be degrading to the extent that a metal 

reinforcement bar was exposed. This observation prompted 

shipyard personnel to arrange alternative liquid waste disposal 

methods and to take the tank out of service in 1983. 

Vicinity of Site 2

Site 2 (fig. 5) of the Initial Assessment Study (IAS) 

(URS Consultants, Inc., 1991) is just west of the OU NSC 

and approximately 0.02 km2. Historically, Site 2 contained 

numerous wooden and concrete block structures including 

a garbage can cleaning facility and a storage area for 

PCB waste and off-line transformers. In the 1980s, two 

dark-stained soil spots were removed during a time-critical 

removal action near former building 399. Soils (to 12 m 

below ground) from monitoring wells (MW01–MW05) and 

boreholes (H-101–H-115) were contaminated with THg 

(U.S. Navy, 1992). THg concentrations ranged from 6.6 to 

31 mg/kg, with a median of 17.5 mg/kg for 42 soils samples 

(table A1). Subsequently, the buildings were demolished; 

some near-surface soils contaminated with mercury, lead, 

and other substances were removed; and a hazardous-andflammable materials warehouse and associated parking areas 

were constructed on the site from 1994 to 1996. This area is 

serviced by the largest stormwater drain system (PSNS015) 

on the base and extends about 1 km northward and about 

600 m eastward, drains 0.19 km2 of impervious area, and is 

the only stormwater drain at BNC that services a large extent 

of pervious areas (0.21 km2 ), such as recreational ball fields. 

The 1.2-m diameter stormwater drain pipe passes through 

the seawall, then drops vertically and extends about 30-m 

horizontally into Sinclair Inlet between a pier and a mooring. 

At the seawall, the pipe is situated between +0.61 m and 

0.61 m (relative to mean lower low water [MLLW]) and much 

of the contributing stormwater drain system is tidally affected 

(Bruce Beckwith, Puget Sound Naval Shipyard, written 

commun., 2008). 

Capture Zone of Sumps

Groundwater in OU NSC and PSNS&IMF of OU B 

Terrestrial is captured by dry dock sumps (fig. 4). PSNS&IMF 

(fig. 3) contains six dry docks and the 0.75 km2 of impervious 

area is serviced by 58 stormwater drain systems. To keep 

the dry docks dry when in use, sump wells are pumped 

intermittently between 15 to 60 minute cycles. The 

time-averaged discharge rates presented in this report include 

times when pumps of the sump wells are on and off. The 

depths of the sump wells for dry docks are as deep as 13 m 

below ground surface. The sump wells for five eastern dry 

docks (Dry Docks 1–5) are interconnected, and sump water 

was pumped through either Pump 4 or Pump 5 at an average 

annual discharge rate of 0.157 m3/s (Bob Johnston, U.S. Navy, 

written commun., 2012). When large ships are being repaired 

in the largest dry dock (Dry Dock 6), the cooling water from 

Sinclair Inlet pumped through ships also flows through the 

sump well at a discharge rate as much as 0.3 m3/s. When Dry 

Dock 6 is empty or when the ship being repaired does not 

discharge cooling water, the sump well is pumped at an annual 

discharge rate of about 0.20 m3/s (Bob Johnston, U.S. Navy, 

written commun., 2012). This pumping of the dry dock sump 

wells results in a zone of groundwater-level depression that 

captures most of the groundwater that would otherwise flow 

to Sinclair Inlet from the area between the eastern boundary 

of PSNS&IMF and near the western boundary of OU NSC 

(Prych, 1997). Additionally, significant amounts of seawater 

from Sinclair Inlet leak into the dry docks directly or through 

sediments below the sediment-water interface outside of the 

dry docks. 
8 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig04

SI-PO

Navy City

PO-Boat ramp

Wright

Creek

Ross er C ke

j kcal B ca Ck keer

nl O r Cye kee

nnA pa il o Cs er ke

Ander os n C er ke

rpS C gni

keer

Gorst Creek

S

NI

CLAIR

NI

LET

S

NI

CLAIR

NI

LET

Cable Area Seaward Boundary PUGET SOUND

0 0.5

0.5

1 Mile

0 1 Kilometer

122°36' 122°38' 122°40' 122°42'

47°34'47°32'

EXPLANATION

Bremerton naval complexZone boundarySampling sites and identification

BNC groundwater wellUSGS stormwater sampleUSGS marine station (surface and bottom)USGS marine water column station (surface)USGS marine water column station (bottom)USGS creek sample

Port

Orchard

Gorst

Bremerton

Vicinity of 

site 2

Capture zone

of sumps 

Zone of direct

discharge

SI-OUT

SI-IN

SI-IN

CZ OUA 204

OUA 203

OUA 206

OUA 241

OUBT 715R

OUBT 718

OUBT 722

PSNSA42

PSNS0152253

OUNSC 311

OUNSC 380

OUBT 709

OUBT 724

OUBT 406R

BNC-71

BNC-39 BNC-52

BNC-52

BNC-60

PSNS 124 PSNS 124.1

USGS National Elevation Data (NED) 2000, 30 meter resolutionUTM zone 10, datum NAD83

A42

Figure 4. Locations of well and stormwater drain sampling sites in the Bremerton naval complex, stream and stormwater sampling sites, and marine water column stations 

sampled by USGS between December 2007 and March 2010, Sinclair Inlet, Kitsap County, Washington.
Study Area 

9 tac11-0637_fig05

T-01 T-02 T-03 T-04 T-05

Well OUBT-722

Seawall

718

MW02

MW05

MW04W

MW03

A42

MW01

H-115

H-104

H-114

H-113

H-112

H-111

H-110

H-109 H-108

H-107

H-106

H-105

H-103

H-102

H-101

2253

LTMP-3 (OUBT-722)

Former

Bldg

399

PSNS015 stormwater drain system

EXPLANATION

PS02 well or borehole MW03PSNS015 vault A42 sampled by USGS on January 9, 2009 and by ENVVESTPSNS015 vault 2253 sampled by USGS on March 31, 2010Temporary well (TW) T-01

Figure 5. Vicinity Site 2 of the Initial Assessment Study including boreholes (labeled H) and decommissioned monitoring wells (labeled MW), Operable Unit B Terrestrial (OUBT) 

wells OUBT-722 and 718, and vaults of the PSNS015 storm water system sampled by U.S. Geological Survey, Bremerton naval complex, Bremerton, Washington, 2009–10.
10 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

OU NSC is 0.11 km2 (fig. 3) and formerly contained the 

Defense Reutilization Marketing Office that recycled materials 

and contained an acid drain pit that was removed in 1995. 

Much of western OU NSC consists of former disposal sites 

and shoreline fill areas used for leveling and extending PSNS 

boundaries. The material used as fill varied with the location, 

but included oily sludge, automobile scrap, construction 

debris, shipyard debris, spent abrasive grit (“blaster sand” 

and copper slag), and other materials. Potential contaminants 

include PCBs, heavy metals, organics, and organotins (U.S. 

Navy, 1995b). Impervious surfaces cover most of OU NSC 

that is served by 16 stormwater outfalls. Most of the 

groundwater in OU NSC is captured by the zone of depression 

of the drainage systems of the six dry docks. 

Numerous waterfront areas in OU B Terrestrial in the 

PSNS&IMF formerly served as disposal sites and shoreline 

fill areas used for leveling and extending PSNS. These areas 

received fill material that included oily sludge, automobile 

scrap, construction debris, shipyard debris, spent abrasive 

grit, and other materials (U.S. Navy, 1992). Concentrations of 

THg in soils from these fill areas of PSNS&IMF were three 

times greater than background (U.S. Navy, 2002), but did 

not approach the levels measured in former Site 2 of NBK 

Bremerton (U.S. Navy, 1992).

About 0.012 km2 along the shoreline in the center of 

western PSNS&IMF (fig. 3) was used as a fill area from 

1960 to 1974 and contains about 53,500 m3 of fill ranging 

in thickness from 11.3 to 15.2 m. Fill materials included 

construction debris, rubble, spent abrasive grit, and dredged 

sediment. In 1998, this area was paved and the Defense 

Reutilization Marketing Office was relocated to this area from 

the OU NSC. As part of the remedial action for OU B Marine 

in 2000 and 2001, the shoreline perimeter was stabilized. This 

site also is part of the disposal site and shoreline fill area in 

central PSNS&IMF. 

The area near the eastern boundary of PSNS&IMF near 

well LTMP-5 (fig. 3) probably is filled with same types of 

material (construction debris, rubble, spent abrasive grit, 

and dredged sediment). This site is covered with gravel 

and some asphalt pavement, and currently is used for bulk 

materials storage.

History of Remediation and 

Environmental Investigations 

Related to Mercury

A synthesis of data on THg concentrations in sediment 

throughout Puget Sound indicated that concentrations were 

higher in OU B Marine between two waterfront piers off 

central PSNS&IMF than in other urban areas of Puget Sound 

(Evans-Hamilton, Inc. and D.R. Systems, Inc., 1987). In 1989, 

personnel from the State of Washington Puget Sound Ambient 

Monitoring Program began monitoring the marine waters 

and sediment of Puget Sound. The highest concentrations 

of THg and PCBs of all the long-term sediment monitoring 

sites were detected in samples collected from Sinclair Inlet 

during the first Puget Sound-wide sampling (Tetra Tech, Inc., 

1990). During the late 1990s, dredging of OU B marine and 

greater Sinclair Inlet for navigational purposes for home port 

expansion of the BNC was proposed. Screening of marine 

sediment to be dredged identified a considerable volume 

of sediment determined to be unsuitable for open-water 

disposal, because of elevated contaminant concentration 

(U.S. Navy, 1999). A confined aquatic disposal pit (fig. 2) was 

developed in 2000 for disposal of dredge spoils from home 

port expansion and contaminated sediment for CERCLA 

purposes. Even after the navigational and CERCLA dredging, 

the level of THg contamination in Sinclair Inlet was of the 

same magnitude as reported for sediment from Bellingham 

Bay associated with the chlor-alkali plant and sediment from 

Commencement Bay associated with the Ruston copper 

smelter (Paulson and others, 2010). Long-term monitoring of 

THg sediment concentrations continues at 1 site in Sinclair 

Inlet by the State of Washington and at 32 sites in greater 

Sinclair Inlet and at 71 sites within OU B Marine by the U.S. 

Navy, as part of the monitoring plan outlined in the Record of 

Decision (ROD). 

During 1990–95, a series of investigations related to 

BNC contamination of groundwater, surface water, and 

dry dock discharges included (1) the IAS (1990); (2) a Site 

Investigation (1990–91); and (3) remedial investigation/

feasibility studies (RI/FS) at OU A (1992–94), OU NSC 

(1993–94), and OU B Terrestrial (1993–95). The U.S. Navy 

and its contractors analyzed water samples for THg collected 

from numerous monitoring wells in the OU A, OU NSC, and 

OU B Terrestrial. Water samples collected from monitoring 

wells in the OUs were analyzed for mercury in a Synoptic 

Groundwater Study between 1998 and 2003 (Grady May, U.S. 

Navy, written commun., 2007). 

The LTMP of the BNC, which began in 2004, continues 

to monitor THg in water from five wells installed during the 

RI/FS and from five new wells installed near the shoreline at 

OU B. Most analyses were performed on unfiltered water, but 

a subset of filtered samples also was analyzed. The second 

five-year review for the BNC (U.S. Navy, 2008a) identified 

mercury contamination in marine sediments and groundwater 

as an on-going concern. The LTMP switched to a more 

sensitive analysis of THg in groundwater in late 2008. 

The ENVironmental inVESTment (ENVVEST) project 

was developed between Federal, State and local partners to 

specifically address the development of total maximum daily 

loads for the Sinclair and Dyes Inlet basin and to improve 

the environmental quality of the adjacent Puget Sound 

Naval Shipyard; the Water Quality Implementation Plan was 

published in 2012 (Washington State Department of Ecology, 

2012a). Scientists from the ENVVEST project assessed the 

sources and effects of fecal coliform (FC) pollution within the 
Synthesis of Existing Data 11

Sinclair and Dyes Inlets (May and others, 2005). ENVVEST 

also developed a watershed-receiving water model for FC 

pollution, fate, and transport to support the total maximum 

daily load assessment of FC loading (Johnston and others, 

2009); assessed the sources of contamination, including 

Hg, from creek basins and stormwater runoff as function 

of upstream land use and cover (Brandenberger and others, 

2007; Cullinan and others, 2007); and evaluated chemical 

contaminant levels in demersal fish and invertebrates in 

Sinclair Inlet and other areas of the Puget Sound (Johnston 

and others, 2007).

In August 2009, the ENVVEST ambient monitoring 

program was initiated (Johnston and others, 2011) with the 

following objectives: (1) establish a baseline for assessing 

continuous process improvement of shipyard operations and 

other sources of contamination into Sinclair and Dyes Inlets; 

(2) provide data for validation of proposed mixing zones and 

model verification; (3) obtain data and information on toxicity 

of effluents and receiving waters for National Pollutant 

Discharge Elimination System (NPDES) permit requirements 

for the shipyard; and (4) develop procedures needed to meet 

ambient monitoring requirements. Additionally, Brandenberger 

and others (2010) evaluated the atmospheric deposition of 

selected metals (including Hg), polyaromatic hydrocarbons 

(PAHs), polybrominated diphenyl esters (PBDEs), and 

biomarkers to assess potential inputs of combustion-derived 

constituents to the Puget Sound airsheds.

Synthesis of Existing Data

Types of analyses of total mercury are presented by 

media of the sample. THg in an unfiltered whole water 

(unfiltered) sample measured by other agencies is defined as 

WTHg and is reported in concentrations units of nanograms 

per liter (ng/L). Likewise, concentrations of MHg in unfiltered 

water are referred to as WMHg. Total mercury in the filtrate 

passing through a quartz fiber filter (QFF) (0.7 μm nominal 

pore size) measured by USGS, the U.S. Navy, and King 

County Department of Natural Resources and Parks (2001) 

is referred to as filtered total mercury (FTHg) and is reported 

in concentration units of nanograms per liter. Likewise, MHg 

passing through a QFF is referred to as filtered methylmercury 

(FMHg). Projects by ENVVEST, the U.S. Navy, King County 

Department of Natural Resources and Parks (2001), and 

Brandenberger and others (2010) generally report WTHg 

concentrations, with some also reporting FTHg concentrations.

The total mercury of solids captured by a QFF measured 

by USGS is referred to as particulate total mercury (PTHg) 

and in concentration units of nanograms per liter (ng/L). By 

mass balance, 

WTHg FTHg PTHg. = + (1)

In this study, FTHg and PTHg generally were measured 

at each site. For locations where USGS and others have 

measured THg using modern, analytical sensitive methods, 

comparisons with WTHg data were made by adding FTHg 

concentrations and PTHg concentrations. These comparisons 

will be presented as part of the USGS FTHg data and allow 

the representativeness of the samples collected by USGS to 

be assessed. 

The total suspended solids (TSS) concentration is 

a measure of solids concentrations in the part of sample 

collected the PTHg analysis. The total mercury concentration 

of suspended solids is calculated as: 

THg of suspended solids (ng/mg) = 

PTHg (ng/L) / TSS (mg/L).

(2)

 By conversion, the concentrations unit of THg of 

suspended solids (in nanograms per milligram) is equal to 

the concentration unit of milligrams per kilogram (mg/kg). 

Total mercury concentrations of marine sediment measured 

by Long-Term Monitoring Program (LTMP) of U.S. Navy are 

referred to as STHg and reported in milligrams per kilogram. 

Existing data by others relating to Puget Sound seawater, 

atmospheric deposition, creeks, stormwater, municipal 

effluents and BNC stormwater are examined for a number of 

mercury species in the section “Sources and Sinks of Filtered 

Total Mercury to Sinclair Inlet.” Mercury data for groundwater 

outside of the BNC and diffusive fluxes of FTHg from the 

Sinclair Inlet sediment were not found in the literature. 

Puget Sound Sources

Between June 1999 and June 2000, the King County 

Department of Natural Resources and Parks (2001) measured 

FTHg and WTHg 13 times at 3 depths at 3 stations in the 

main basin of Puget Sound (fig. 1): north of Bainbridge Island 

(KSBP01), east of Bainbridge Island (KSSK02), and at north 

end of Colvos Passage (COLVOS PASS), which flows north to 

the mixing zone with Rich Passage. For this report, mid‐depth 

samples were selected as representative of the Puget Sound 

seawater that flows into Sinclair Inlet. Median WTHg 

concentrations for the three stations ranged from 0.33 to 

0.34 ng/L. Except for one sample, FTHg concentrations were 

greater than the minimum detection limit of 0.1 ng/L and 

less than the reporting level of 0.5 ng/L. The median FTHg 

concentration was 0.2 ng/L. 

Concentrations of WTHg at varying depths from the 

passages connecting Sinclair Inlet to Puget Sound were 

measured during the ENVVEST project (ENVironmental 

inVESTment Project [2006] as cited in Paulson and others, 

2010). The median WTHg concentrations of bottom water 

in the Port Orchard Passage system and Rich Passage was 

1.3 ng/L. The total suspended solids (TSS) concentrations, in 

a subset of 10 samples, ranged from 0.6 to 2 mg/L. 
12 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Atmospheric Deposition

Total Mercury

THg falls on the terrestrial and marine surface of the 

Sinclair Inlet basin as both dry particles during dry periods 

and as FTHg and PTHg in wet precipitation. THg on 

atmospheric particles, in aerosol water droplets, and as THg 

vapor are captured by rainfall. Brandenberger and others 

(2010) collected THg atmospheric deposition data during 

18 two-week sampling events between September 2008 and 

October 2009 using bulk precipitation collectors, which 

collected both dry and wet deposition, at a site outside of 

Sinclair Inlet adjacent to Rich Passage in Manchester (fig. 1). 

The median concentration of WTHg was 4.75 ng/L. During 

two sampling events in September and October 2008 during 

which 1.0 and 3.8 cm of rain fell, WTHg concentrations 

exceeded 10 ng/L. During 13 sampling events in which 

0.3–7 cm of rain fell, WTHg concentrations averaged 

4.2± 1.3 ng/L and was not correlated with rainfall amounts 

(p value=0.64). 

Methylmercury 

Brandenberger and others (2010) measured MHg 

concentrations in atmospheric precipitation collectors at a site 

in Manchester between September 2008 and October 2009, 

that included three sampling events in which little or no rain 

fell. Concentrations of MHg in unfiltered water (WMHg) 

poured and rinsed from bulk atmospheric precipitation 

collectors were measured during 18 two-week sampling 

events. The WMHg concentrations in the 60 mL of rinse water 

for the three sampling events in which little or no rain fall, 

ranged from 0.0363 to 0.509 ng/L. Concentrations of WMHg 

during the other 15 sampling events (125 to 797 total mL of 

rain water collected) averaged about 0.08 ng/L and ranged 

from 0.0172 to 0.263 ng/L. 

Sources Discharging into Greater Sinclair Inlet

From 2002 to 2005, water samples from creeks 

and stormwater basins draining to Sinclair Inlet and two 

wastewater treatment plants were collected for the ENVVEST 

project. Sampling event mean concentrations were obtained 

using flow-weighted, time-paced, or sequential grab 

composites (ENVironmental inVESTment Project, 2006). 

Concentrations of WTHg were measured using sensitive 

analytical methods with a detection limit of 0.17 ng/L and 

a reporting limit of 0.5 ng/L for THg in unfiltered samples 

(ENVironmental inVESTment Project, 2006). Quality 

assurance data are in tables A2–A5.

Creeks Discharging to Greater Sinclair Inlet

From 2002 to 2005, four creeks (Blackjack, Anderson, 

Annapolis, and Gorst Creeks; fig. 2) in the Sinclair Inlet basin 

and many other creek basins outside of the Sinclair Inlet basin, 

including Olney Creek just outside the seaward boundary 

of the model box at the cable area (fig. 2), were sampled 

(ENVironmental inVESTment Project, 2006). Samples were 

collected for wet season base flow (March), dry season base 

flow (September), and a range of storm conditions (table A6). 

Streamflow, concentrations of WTHg, and concentrations 

of various other water quality constituents were measured 

(ENVironmental inVESTment Project, 2006).

During dry season base flow (September 2002), 

when TSS concentrations were 10 mg/L or less, WTHg 

concentrations in water from Blackjack, Anderson, Annapolis, 

and Olney Creeks were less than 2 ng/L. During wet season 

base flow and storm events, WTHg and TSS concentrations 

commonly increased by about one order of magnitude. During 

wet season base flow, concentrations of WTHg from Blackjack 

Creek increased to 5 ng/L or greater. Concentrations of WTHg 

concentrations during storms increased to about 9 ng/L in 

Blackjack Creek, increased to about 12 ng/L in Anderson 

Creek, and increased to greater than 20 ng/L in Annapolis and 

Olney Creeks.

The USGS examined the WTHg concentrations in surface 

waters in relation to total aluminum concentrations to evaluate 

the partitioning of WTHg between aqueous and particulate 

phases. Because aqueous aluminum concentrations in neutral 

pH waters usually are low, high total aluminum concentrations 

usually are associated with high concentrations of solids in 

the analyzed whole water sample. A strong correlation of 

WTHg with total aluminum in an unfiltered surface water 

sample would suggest that most of the THg transported during 

storm events was associated with particles. Concentrations 

of WTHg in Blackjack, Anderson, Annapolis, Upper Gorst, 

and Olney Creeks were well correlated (p value <0.05; 

table A7) with total aluminum concentrations, indicating 

much of the THg was transported by particles containing 

aluminum. Concentration of WTHg also were correlated with 

concentrations of TSS in Blackjack, Anderson, Annapolis, and 

Olney Creeks, with the slopes of the regression ranging from 

0.064 ng/mg in Anderson Creek to 0.17 ng/mg in Annapolis 

Creek (fig. A1 and table A7). In contrast to the four creeks 

previously described, WTHg concentrations collected from 

Gorst Creek were not significantly correlated (p value=0.11) 

with TSS concentrations. 
Synthesis of Existing Data 13

Greater Sinclair Inlet Stormwater

Stormwater samples in the Sinclair Inlet basin (table A8) 

were collected from one combined sewage overflow 

(CSO) drain (CSO16, fig. 2) and three stormwater outfalls 

(LMK122 in Gorst, B-ST28 in Bremerton, and PO-BLVD 

in Port Orchard) that discharge into Sinclair Inlet (fig. 2) 

(ENVironmental inVESTment Project, 2006). For comparison, 

stormwater data are presented from two outfalls outside of the 

study area: LMK038 in Manchester (fig. 1) and B-ST12 in east 

Bremerton (fig. 2). Samples for WTHg analysis were collected 

from a composite of three grab samples during storm events. 

Although data on many ancillary parameters were obtained 

from the individual grab samples, data on concentrations of 

total aluminum, total organic carbon, and TSS were not always 

obtained on the composite sample from which the aliquot 

for WTHg was taken. The highest WTHg concentrations 

in samples collected from CSO16, B-ST28, and PO-BLVD 

(fig. 2) were 33.8, 25.27, and 19.52 ng/L, respectively, 

whereas 3 of the 11 outfall samples collected from LMK122 

contained WTHg concentrations between 41.9 and 56.1 ng/L 

(table A8). In contrast, maximum WTHg concentrations in the 

B-ST12 and LMK038 outfalls outside of the study area were 

44.78 and 19.23 ng/L, respectively.

WTHg in unfiltered stormwater was highly correlated 

with total aluminum at sites CSO16, B-ST28, PO-BLVD, 

and LMK038 (table A7). Concentrations of WTHg also 

were regressed in stormwater against the concentrations 

of TSS (fig. A2, table A7). The WTHg concentrations of 

CSO16 and outfalls LMK122, B-ST28, and PO-BLVD 

draining into Sinclair Inlet were well–correlated (p <0.05) 

to TSS concentrations with slopes of 0.42, 0.46, 0.19, 

and 0.10 ng/mg, respectively. WTHg concentrations in 

outfall LMK038 in Manchester were correlated with TSS 

concentrations (slope of 0.15 ng/mg). In contrast, WTHg 

concentrations in stormwater from drain B-ST12, located 

just outside of the Sinclair Inlet basin, were not correlated 

with TSS. 

Concentrations of WTHg concentrations in stormwater 

generally were similar to WTHg measured in nearby creek 

water for a given storm event. During the storm event of 

January 17, 2005, the WTHg concentration from Annapolis 

Creek was 27.31 ng/L (table A6), whereas the WTHg 

concentration in stormwater from nearby PO-BLVD in Port 

Orchard was 12.95 ng/L in the outfall, and was 41.9 ng/L in 

the LMK122 outfall in Gorst (table A8). During the storm 

event of March 19, 2005, the WTHg concentration from 

Olney Creek was 16.96 ng/L (table A6), whereas the WTHg 

concentration from the CSO16 outfall in Bremerton was 

15.1 ng/L and in the B-ST28 outfall in western PSNS was 

11.06 ng/L (table A8). In contrast, the WTHg concentration in 

the B-ST12 outfall in eastern Bremerton was only 5.25 ng/L 

during this storm. 

Municipal Wastewater Treatment Plant Effluent

Unfiltered effluent from two wastewater treatment 

plants were sampled and analyzed for WTHg in support of 

the ENVVEST project between 2004 and 2005 (table A9). 

Concentrations of WTHg in four final effluents from the City 

of Bremerton wastewater treatment plant, which discharges 

into Sinclair Inlet west of OU A, ranged from 8.45to 34.8 ng/L 

(ENVironmental inVESTment Project, 2006). Concentrations 

of WTHg in eight final effluents collected from the South 

Kitsap Water Reclamation Facility of West Sound Utility 

District wastewater treatment plant, which discharges into the 

convergence zone east of the cable area seaward boundary 

(fig. 2), ranged from 4.46 to 39.83 ng/L. 

Bremerton Naval Complex

Sources of THg from the BNC include surface water 

that is limited to stormwater drains, groundwater discharge, 

and the industrial discharges from the dry dock drainage 

relief systems and the steam plant. THg was not detected 

at a reporting level of 200 ng/L in any filtered or unfiltered 

samples collected from BNC dry dock relief drainage systems 

in May 1994 (U.S. Navy, 2002).

Stormwater Discharged from Bremerton 

Naval Complex

Surface water was sampled only in OU NSC Terrestrial 

during the RI/FS process (1990s) when reporting levels were 

200 ng/L. Concentrations of WTHg were determined in 

unfiltered samples from 11 stormwater drainage systems at 

the BNC (table A10) for the ENVVEST project (2002–05) 

using sensitive analytical methods with reporting levels 

of 0.17 ng/L. Ancillary constituents also were analyzed in 

selected samples. 

Zone of Direct Discharge

Concentrations of WTHg ranging from 4.92 to 

42.80 ng/L were measured in stormwater from BNC 

drainage systems in the zone of direct groundwater discharge 

area (stormwater drain systems PSNS008 and PSNS011) 

(table A10).

Vicinity of Site 2

Stormwater from outfall PSNS015 was collected from 

the vault A42 (fig. 5) in the Vicinity of Site 2. High WTHg 

concentrations (as much as 1,131 ng/L) were of particular 

note (ENVironmental inVESTment Project, 2006). WTHg 

concentrations were not correlated with total aluminum 

concentrations (table A7). Although WTHg concentrations 

from PSNS015 were correlated with TSS, the y-intercept 

was -192 ng/L, which suggests caution in interpreting 

this correlation. 
14 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Capture Zone of Sumps

During the RI/FS process, stormwater from OU NSC 

was collected and analyzed for THg using a method with 

a reporting level of 200 ng/L (U.S Navy, 1995b). In 1993, 

2 of 11 unfiltered samples collected from stormwater drains 

in OU NSC contained detectable WTHg concentration 

ranging 230–380 ng/L with registered turbidity values greater 

than 200 nephelometric turbidity units (NTU). The WTHg 

concentration of a single sample collected from OU NSC 

stormwater drain in 1999 was 210 ng/L, slightly above the 

reporting level of 200 ng/L.

The WTHg concentrations in stormwater collected in 

the PSNS&IMF (stormwater drains PSNS115.1, PSNS124, 

and PSNS126, fig. 3) for the ENVironmental inVESTment 

Project (2006) ranged from 11.8 to 44.0 ng/L. WTHg 

concentrations greater than 10 ng/L were detected even when 

TSS concentrations were low (fig. A2). This suggests that a 

significant amount of the WTHg was in the aqueous phase 

in BNC stormwater, or that the content of mercury in the 

suspended solids in BNC stormwater was higher than the 

content of suspended solids discharging from creek basins. 

Only WTHg concentrations collected from PSNS126 were 

correlated to TSS with a slope of 0.46 ng/mg. Additional 

sampling using different methods would be required to 

evaluate the nature of the THg in the stormwater of the 

PSNS&IMF. 

Groundwater in Bremerton Naval Complex

Prior to the LTMP groundwater program, FTHg and 

WTHg concentrations throughout BNC were measured 

for four studies: Initial Assessment Study (1990), Site 

Investigation (1990–91), Remedial Investigation/Feasibility 

Studies (RI/FS) (1993–95), and Synoptic Groundwater 

Monitoring (1998–2002). Using methods with detection 

limits ranging between 100 and 200 ng/L, a total of 

308 measurements of FTHg concentrations were qualified 

as not detected or estimated, and 46 of 316 measurements of 

WTHg were greater than detection limits between 100 and 

200 ng/L. High turbidity, high TSS concentrations, and (or) 

high aluminum concentrations in unfiltered water indicate 

that 40 of these measurements were not representative of the 

groundwater because of inadequate well development. 

The Record of Decision provides for post-remediation 

monitoring to be used in five-year reviews to assess the effects 

of the initial and subsequent remedial actions. The LTMP 

examines groundwater resources of OU A, OU B-Terrestrial, 

and OU NSC. The LTMP continues to monitor groundwater 

for THg, other dissolved metals, and organic contaminants 

in five wells installed during the Remedial Investigation and 

five new LTMP wells installed in 2004 in close proximity 

to the shoreline. In the second 5-year review (U.S. Navy, 

2008a), mercury contamination in groundwater continued 

to be a concern. Most of the analyses were performed on 

unfiltered water using a method with a reporting level of 

200 ng/L. A subset of samples was analyzed in 2005 for THg 

concentrations in filtered and unfiltered water. In 2008, the 

LTMP began collecting WTHg samples using “clean hands, 

dirty hands” sampling techniques and measured WTHg 

using a low-level analytical method, which resulted in a 

WTHg reporting level of 1 ng/L (Dwight Leisle, U.S. Navy, 

written commun., 2010). During 2008 and 2009, WTHg 

concentrations in unfiltered groundwater from the nine wells 

other than LTMP-3 likely were affected by the presence 

of solids; TSS concentrations in six samples ranged from 

6 to 65 mg/L, and turbidity values of 55 and 42 NTUs were 

measured during 2008 and 2009, respectively (table A11). No 

analyses of methylmercury were performed.

Zone of Direct Discharge

Three WTHg concentrations, which were measured 

using the method that the high detection limits (2004–07) 

in groundwater collected from well LTMP-1, were between 

the detection limit and the reporting level. When methods 

with lower detection limits were used in 2008 and 2009, 

groundwater from LTMP-1 contained the second highest 

WTHg concentrations (156 ng/L in 2008 and 56.8 ng/L in 

2009) of the 10 wells sampled (table A11). 

Vicinity of Site 2

In the Initial Assessment Study, the two samples judged 

to be analytically acceptable using quality assurance criteria 

had exceptionally high WTHg concentrations from Site 2 

wells and were accompanied by high aluminum concentrations 

in unfiltered water. Although these observations provide little 

information about the aqueous phase of groundwater, they 

confirm the presence of mercury contaminated soils at Site 2. 

During the Synoptic Groundwater Monitoring Study by the 

U.S. Navy in 2002 (Grady May, U.S. Navy, written commun., 

2007), WTHg was detected only in unfiltered water collected 

from monitoring well 806 (121 m west of well LTMP-3) 

(fig. 3). WTHg concentrations in groundwater collected from 

well 806, located west of Site 2, ranged from 200 to 500 ng/L. 

No field parameters or samples for total aluminum or total 

suspended solids were collected in 2002 and 2003 from OU B 

Terrestrial to assess the bias due to high turbidity.

All wells installed in Site 2 during the RI/FS were 

decommissioned during the remediation of the site, so 

the sampling during July–August 1994 during the RI/

FS (U.S. Navy, 2002) provides the only salinity data for 

groundwater under this site. The salinity of groundwater 

from well PS02-MW05, located near the seawall (fig. 5), 

was 23.76 on the practical salinity scale, and the salinity of 

groundwater from well PS02-MW01 located 50 m inland 

from PS02-MW05 was 6.54. About 200 m inland, salinity of 

groundwater from well PS02-MW04W was lower than the 

other well from Site 2, whereas salinity of groundwater from 

the well (MW03) closest to the PSNS015 stormwater drain 

vault A42 was 5.63. 
Methods for USGS Sampling 15

Between 2004 and 2007, 9 of the 16 samples judged to 

be analytically acceptable using quality assurance criteria 

(detection limit of 200 ng/L) measured in groundwater (U.S. 

Navy, 2007a) were collected from well LTMP-3 (fig. 3) and 

ranged from 0.98 to 6.69 μg/L (table A12). During March, 

May, and July 2005, FTHg concentrations from well LTMP-3 

ranged between 0.21 and 0.97 μg/L. WTHg concentrations in 

unfiltered water from LTMP-3 (table A11) were the highest 

during autumn 2008 and spring 2009 sampling (3,680 and 

1,190 ng/L, respectively). 

Capture Zone of Sumps

Concentrations of WTHg and FTHg were not detected 

at a reporting level of 200 ng/L in groundwater collected 

between 2004 and 2007 from six of seven wells within the 

capture zone of dry dock sumps (U.S. Navy, 2007a). In 

2004 and 2005, four unfiltered samples from well LTMP-5 

(named OUBT-724 by USGS) near the eastern boundary of 

PSNS&IMF contained WTHg concentrations from 0.23 to 

5.24 μg/L (table A12). The value of 5.24 μg/L was obtained on 

October 18, 2005, at a tidal stage higher than other LTMP-5 

samples collected and did not seem to be affected by excess 

solids (5 μg/L total aluminum and 0.96 mg/L TSS). Using the 

more sensitive analytical methods, groundwater from LTMP-5 

collected in 2008 and 2009 contained the third highest WTHg 

concentrations (41.6 and 27.5 ng/L, respectively). During 

2008 and 2009, the median concentration in groundwater 

collected from the other six wells in the capture zone of sumps 

was 3 ng/L, with a range from 0.33 to 30.9 ng/L. 

Methods for USGS Sampling

Between December 2007 and March 2010, USGS 

sampled various sources of water in the BNC (fig. 4) for 

mercury concentrations, including: (1) industrial discharges 

from the steam plant in the Zone of Direct Discharge and 

two dry dock systems in the Capture Zone of Sumps, 

(2) stormwater in three drain systems in the Vicinity of the 

Site 2 and the Capture Zone of Sumps, (3) groundwater from 

12 monitoring wells from the three zones, and (4) groundwater 

from five intertidal piezometers in the Vicinity of Site 2 (inset 

in fig. 5). Sources sampled outside of the BNC (figs. 1 and 

4) included: (1) surface water in five creeks, (2) stormwater 

in three drains, and (3) effluent from two wastewater 

treatment plants. Sampling and processing procedures were 

in accordance with the USGS National Field Manual (U.S. 

Geological Survey, variously dated), and analytical procedures 

are described in detail in Huffman and others (2012). Between 

December 2007 and February 2008, equipment for sampling 

FTHg from dry docks and groundwater was acid cleaned at 

room temperature at the USGS Washington Water Science 

Center (WAWSC) laboratory, Tacoma, Washington, as 

described by Lewis and Brigham (2004) and FTHg samples 

stored in glass bottles was analyzed by the USGS National 

Water Quality Laboratory (NWQL), Lakewood, Colorado. 

Beginning in March 2008, all equipment and perfluoroalkoxy 

(PFA) bottles were hot acid-cleaned at the Wisconsin Mercury 

Research Laboratory (WMRL), Middleton, Wisconsin. Only 

acid-cleaned, 0.45 μm pore-size Meissner ALpHA® CMF 

0.45‐442 cartridge filters and pre-baked quartz filter filters 

(QFF) were used to filter water for analysis of FTHg. The 

methods and quality control data are presented in Huffman 

and others (2012) and are briefly described in this report. All 

data are reported in Huffman and others (2012) and deemed 

acceptable, except where noted below.

Sampling

Creeks

 Water samples from five creeks were analyzed by USGS 

during May and July 2008 (fig. 4). Field properties were 

monitored directly in the creek, and samples were collected 

after pumping unfiltered water from the centroid of flow 

through PFA tubing using a peristaltic pump equipped with a 

small piece of flexible C-flexTM tubing for about 5 minutes. 

Water for FTHg analysis was filtered through a cartridge filter. 

After removing the cartridge filter, raw water was collected 

first into a 1-L sterile polyethylene terephthalate copolyester 

(PETG) bottle for PTHg analysis, then into a high-density 

polyethylene (HDPE) bottle for TSS analysis near the end of 

sampling cycle. Samples for ancillary parameters (particulate 

organic carbon (POC), particulate nitrogen (PN), dissolved 

organic carbon (DOC), filtered total iron, total manganese 

and nutrients, and TSS were collected using the techniques 

described in Huffman and others (2012), except that 

turbidity was only measured in May. Additionally, samples 

for anions and cations were filtered with the Pall cartridge 

filter (Aqua‐PrepTM 0.45 μm pore size, 79 mm diameter) and 

acidified in the field. The FTHg results from the July sampling 

are qualified and considered to be estimated because of higher 

than usual concentration in the associated field filtering blank 

(0.33 ng/L), and a high relative percent difference (RPD) 

of 51 percent for two field duplicate samples (Huffman and 

others, 2012).

Stormwater

Three stormwater samples in the BNC and one drain 

in Sinclair Inlet basin (Navy City) were collected during 

higher low tide (-0.47 m MLLW) on January 7, 2009, 

during the height of a major storm (0.6 and 4.0 cm of 

rainfall on January 6 and 7, respectively). For the BNC 

stormwater drains, a 30-cm long polytetrafluoroethylene 

(PTFE) sampling port secured to a location-specific length 
16 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

of 0.25 in. outside-diameter PTFE tubing was lowered 

into the stormwater drain vault. Water was pumped using 

a peristaltic pump at about 300 mL/min through a flow 

chamber containing multimeter while field parameters were 

continuously monitored. A specific conductance reading 

less than 100 μS/cm ensured the absence of seawater in 

these tidally influenced stormwater drains. After the field 

parameters stabilized, a turbidity measurement was made 

using a Hach® model 2100P portable turbidimeter. Samples 

for FTHg, FMHg, PTHg and TSS were collected in a 2-L 

PTEG bottle; POC-PN-DOC samples were collected in 

amber glass bottles; and samples for analyses of filtered iron, 

manganese, and nutrients were filtered in the field into HDPE 

bottles as described in Huffman and others (2012). Similarly, 

the stormwater sample from the Navy City (fig. 4) site was 

collected by suspending the sampling port in the middle of a 

culvert opening and pumping water with a peristaltic pump. 

The other two stormwater drain samples (Sheridan Road in 

fig. 1 and PO-Boat ramp in fig. 4) were collected directly from 

the end of the stormwater drain pipe during the lower low tide 

1 day later during the latter stages of the storm.

Saltwater leakage from the contaminated soils of the 

former Site 2 (U.S. Navy, 1992) to the stormwater drain 

PSNS015 and out to Sinclair Inlet was examined during 

two ebbing tidal periods in which little rain had fallen 24 hours 

prior to sampling. On December 29, 2009, and March 31, 

2010, grab samples for FTHg were collected from vault 

PSNS015-2253 (fig. 5) as previously described for sampling 

of BNC stormwater. A YSI Inc. datasonde and sampling port 

were deployed into the stormwater drain. The individual grab 

samples were sent to the NWQL for analysis. Each day, an 

equal-volume composite of each grab sample was collected 

in a 2-L PETG bottle in the field, processed in the WAWSC 

laboratory, and delivered to NWQL for FTHg analysis and 

delivered to WMRL for FTHg and PTHg analysis; TSS was 

analyzed by the WAWSC laboratory. On December 29, 2009, 

rain started falling 4 hours into the ebbing tide. When salinity 

of the drain water started to decrease just as the top of the 

stormwater drain became visible, operations were terminated 

after collecting six grab samples for FTHG and the composite 

sample. Because of the complication of interpreting the effect 

of the rain event and the discrepancy in the result of the 

interlaboratory comparison of FTHG between NWQL and 

WMRL (Huffman and others, 2012), all data except PTHg 

and TSS values in the composite sample were disregarded. 

On March 31, 2010, the tidal cycle study was repeated with 

a Price AA velocity meter measuring water velocity at the 

center of the drain pipe using the methods of Rantz and others 

(1982). During the 24 hours prior to sampling, 0.13 cm of 

rain fell at the Bremerton Airport; 3.1 cm of rain fell between 

the 24 and 48 hours prior to sampling (National Oceanic and 

Atmospheric Administration, 2012). Light rain fell during 

sampling with minor decreases in salinity, and 10 grab 

samples were collected for FTHg and the composite sample. 

Municipal Effluents

Composite samples of effluent water were collected from 

the wastewater treatment plants of the West Sound Sewer 

Utility District (Port Orchard) and the City of Bremerton in 

May, July, and August 2008. Five times during the daytime 

shift, an employee of each wastewater treatment plant 

collected a grab sample of final effluent after chlorination in 

a 1-L PETG bottle. At the end of the shift, USGS personnel 

picked up the five bottles (chilled over ice) and transported 

them to the WAWSC laboratory. The effluent from the West 

Sound Sewer Utility District is not included in the mass 

balance of mercury to Sinclair Inlet because it does not 

discharge into Sinclair Inlet and is presented for comparison 

purposes only.

Bremerton Naval Complex Industrial Discharges

Water samples were collected by USGS in the effluent 

wet well of the steam plant in the Zone of Direct Discharge 

monthly between March and June 2008. Because the PTFE 

sampling port would not fit between the gratings at the top 

of the wet well, a coupling containing a 10 cm piece of 

open 1.3-cm diameter PFA tubing was attached to 0.64-cm 

PTFE tubing and samples were collected using a peristaltic 

pump in the same manner described for collecting BNC 

stormwater samples.

For the first sampling event of the drainage relief systems 

of Dry Dock 1–5 from Pump 4 (December 2007) and Dry 

Dock 6 (February 2008), a grab sample was collected near the 

elevation of the sump and a composite sample was collected 

using an automatic sampler located several levels above the 

sump. The grab sample was filtered through a cartridge filter 

into 250 mL glass bottles. After February 2008, the sample 

was filtered into a 500 mL PFA bottle. Because stagnation of 

water in the vertical riser between the drainage sump and the 

automatic sampler, located on the upper levels of the sump 

wells, could affect the biochemistry of the ambient drainage 

water, the composite sampler location was deemed unsuitable 

for continued collection of mercury samples, especially for 

the FMHg. Following the first sampling, all dry dock samples 

were collected from the sump level of the dry dock drainage 

relief system. Dry Docks 1–5 were sampled directly from a 

port on the discharge pipe of Pumps 4 or 5. Dry Dock 6 was 

sampled by lowering the sampling port assembly, as described 

for stormwater sampling, through a standpipe near the pump 

and collecting sump water using a peristaltic pump.

The six dry dock samples collected between December 

2007 and February 2008 were analyzed by the NWQL, which 

has a reporting level of 10 ng/L for FTHg concentrations. 

Because of the failure to detect FTHg concentrations at a 

reporting level of 10 ng/L, industrial samples for FTHg 

collected between March and June 2008 were analyzed by the 

WMRL using a method with a reporting level of 0.04 ng/L. 
Methods for USGS Sampling 17

The range of median concentrations of the mixed data set was 

calculated by setting undetectable concentrations analyzed by 

NWQL to zero (lower limit) and reporting 6 ng/L as estimated 

by NWQL (upper limit) (Helsel and Hirsch, 1992). All PTHg 

concentrations were measured by the WMRL.

In April 2008, sample collection for FMHg concentration 

from Dry Docks 1–5 and Dry Dock 6, and the steam plant 

included a number of ancillary parameters associated with 

organic carbon and reduced constituents, as well as POC-PNDOC, filtered total iron and manganese, filtered nutrients, and 

unfiltered ferrous iron and sulfide. 

Groundwater

Base-Wide Sampling

Twice in 2008 (January 28–February 2 and April 21–24), 

USGS collected water samples from 11 BNC wells (fig. 4). 

Four wells were in OU A (OUA-203, 204, 206 and -241) 

in the zone of direct discharge. Two OU B Terrestrial 

wells were sampled in the Vicinity of the Site 2 (OUBT-722 

and OUBT-718). Five wells (OUNSC-311 and -380, and 

OUBT-709, -406R and -724) were sampled within the capture 

zone of the dry dock sumps. Groundwater from shoreline 

well OUNSC-311 reflects OU NSC groundwater being 

captured by the dry dock sumps. The nearby, deeper, well 

OUNSC-380 contained fresher water, which likely represents 

ambient regional groundwater. A well in western PSNS&IMF 

(OUBT-709) and well in eastern PSNS&IMF (OUBT-724) 

were located along the shoreline in fill material. One well 

sampled in central PSNS&IMF (OUBT-406R) was located 

near the former oil tanks of a power plant.

 After removal of the well cover at a well location, 

any water in the well cavity around the polyvinyl chloride 

(PVC) casing was bailed manually and with intermittent 

pumping from a dedicated peristaltic pump, as needed. After 

a water level measurement was taken, a PTFE sample port 

secured to a well-specific length of 0.25-in. diameter PTFE 

tubing was lowered into the PVC casing to the middle of the 

screened casing. Using a peristaltic pump, groundwater was 

pumped at approximately 300 mL/min, while field parameters 

(dissolved oxygen, temperature, specific conductance, and 

pH) were continuously monitored. After at least three casing 

volumes of water were purged and the field parameters 

stabilized, including turbidity using a portable turbidimeter 

(Hach® model 2100P), groundwater sampling began in the 

sequence previously described for stormwater sampling with 

the exception that samples for FTHg were filtered through 

cartridge filters in the field. 

For the first groundwater sampling event (January 28–

February 2) that were analyzed by the NWQL, FTHg 

concentrations from three of the four OU A wells, both 

OU NSC wells, and three of the five OU BT wells were less 

than the reporting level (10 ng/L). In April, FTHg samples 

were collected in PFA bottles and analyzed by the WMRL 

(reporting level of 0.04 ng/L). 

In April 2008, samples for FMHg and ancillary 

constituents described from BNC stormwater were collected 

from wells OUBT-718, -722, and -724, OUA-206, and 

OUNSC-380. After the well was purged and field parameters 

stabilized, field spectrometric measurements of sulfide and 

ferrous iron were made. Sampling for FTHg, FMHg, PTHg, 

POC-PN-DOC, filtered iron, manganese and nutrients, and 

TSS were processed in same manner as described in Huffman 

and others (2012) for the collection of stormwater samples. 

Tidal Studies

On May 6 2008, filtered groundwater was sampled 

in well OUBT-722 at about 2-hour intervals from 2 or 3 

depths: near the bottom of the screened interval, the middle 

of the screened interval or at the water table (whichever 

was lowest), and near the water table when it was above 

mid‐screen. Samples were filtered through a cartridge filters 

and analyzed for FTHg concentrations at the NWQL. Salinity 

was calculated from measured specific conductance values in 

unfiltered samples pumped from the sampling port located at 

the bottom of the screened interval. Water levels in the well 

periodically were measured with a steel tape, water levels in 

Sinclair Inlet periodically were measured with a surveyor’s 

level and rod, and the difference between well and Inlet water 

levels periodically were measured using a manometer board.

 At about 1-hour intervals, during June 4–5, 2008, 

groundwater was sampled from well OUBT-722 just below 

the fluctuating water table and filtered through a cartridge 

filter for FTHg analysis. Data for salinity and water level also 

was collected similar to that described for the May 6, 2008, 

tidal study. Additionally, five temporary piezometers (inset 

in fig. 5) were installed within the intertidal zone and were 

sampled at about 1-hour intervals (Huffman and others, 2012). 

Water pumped from the piezometers was filtered through 

a cartridge filter and analyzed for FTHg concentration by 

the WMRL. The specific conductance and temperature of 

unfiltered samples were measured in the field. Water levels 

in the piezometers periodically were measured with a steel 

tape and the difference between piezometer and Sinclair Inlet 

water levels periodically were measured using a manometer 

board. At least one PTHg and TSS sample from each of the 

five piezometers (nine total samples) and at least one FMHg 

sample from each of the five piezometers (six total samples) 

was collected. The only ancillary data collected in association 

with these FMHg samples were salinity.
18 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Laboratory Processing

With the exception of the wastewater-treatment plant 

effluents and stormwater drain samples, water samples for 

FTHg and FMHg were filtered in the field and acidified at the 

WAWSC laboratory within 6 hours with 20 mL of 6 molar 

hydrochloric acid per liter of water in a laminar flow hood, as 

described by Lewis and Brigham (2004). Raw water samples 

were processed for analysis of PTHg, as described by Lewis 

and Brigham (2004). TSS was measured gravimetrically using 

0.4 μm pore-size, 47-mm diameter, Nuclepore® polycarbonate 

filters (Huffman and others, 2012). 

After returning to the WAWSC laboratory, each of the 

two sets of grab samples from a specific wastewater treatment 

plant was composited in a 5-L Teflon bottle. Each composite 

sample was split into five 1-L PETG bottles for processing of 

samples for analyses of FTHg, PTHg, FMHg concentrations 

and the various ancillary analyses, as previously described for 

sampling of stormwater. Wastewater and stormwater collected 

in PETG bottles were filtered through a quartz fiber filter 

(QFF) held in a Savillex® PFA filtering tower assembly in 

the laboratory laminar flow hood. The laboratory procedures, 

assessment of the quality of the data, and the data are reported 

in Huffman and others (2012).

Mass Balance of Water, Salt, and Total 

Suspended Solids in Sinclair Inlet

The quantification of a THg mass balance in an estuary 

requires a balance of water and solids that transport THg. The 

balance of salt within an estuary is a means to constrain and 

verify the balance of water. In a dispersive dominated estuary, 

the transfer of a chemical constituent across the seaward 

boundary of the estuary (net flux) requires knowledge of the 

gradient of the constituent along the estuary and the dispersive 

properties of the estuary that are controlled by geographical 

features and tides. Calculating the dispersive coefficient 

analytically from first principles for the physically complex 

Sinclair Inlet estuary is beyond the scope of this project. The 

gradient of the constituent along the estuary model can be 

combined with the output of a calibrated numerical baroclinic 

hydrodynamic model to calculate the dispersive flux of a 

constituent across the boundary of an estuary. Given that there 

are no losses or gains in the mass of salt during estuarine 

mixing processes, salt is an ideal constituent to assess 

dispersive transport. For the balance of salt in the Sinclair 

Inlet, the dispersive transport of salt into Sinclair Inlet from 

Puget Sound is constrained by the small salinity difference of 

1 or 2 between Sinclair Inlet and Puget Sound that is spread 

over 10 km through Rich Passage and 20 km through Port 

Orchard and Agate Passages. Quantifying the salt balance also 

is complicated by the inputs near the seaward boundary of the 

model box that include mixing with water from Dyes Inlet 

introduced through Port Washington Passage and the effluent 

from the West Sound Sewer Utility District.

If the estuary is partially mixed, knowledge of the net 

advective flow into the estuary along its main longitudinal 

axis can be combined with concentration data of a constituent 

to calculate the net flux of a constituent into and out of an 

estuary. The validity of any numerical estuarine model can 

be assessed by examining the balance of salt in the estuary, 

because salt is neither created nor lost from the water 

column in a temperate climate estuary (Knudsen, 1900). 

The net advective flow into Sinclair Inlet and its uncertainty 

are dominant factor in the mass balance of THg because 

of the magnitude of flows relative to other water flows 

containing THg. 

Mass Balance of Water and Salt

The measurable salinity difference between the upper 

and lower layers of the Sinclair Inlet water column (table 1) 

suggests Sinclair Inlet can be modeled as being a partially 

mixed estuary. A mass balance model of a chemical constituent 

in a partially mixed estuary requires knowledge of (1) the net 

advection transport, (2) the concentrations of the constituent 

in the new salt water entering the estuary in the lower layer, 

and (3) the transport of fresher water in the upper layer 

leaving the estuary. Because the net advective transport of 

water across the seaward boundary of the estuary is the small 

difference between the large flooding transport and the slightly 

larger ebbing transport, current measurements over several 

lunar periods are required to reduce the uncertainty in the net 

transport sufficiently to be useful in mass balance modeling 

of a chemical constituent. As with the dispersive model, the 

validity of the net transport from current measurements can be 

assessed by examining the salt balance. 

Sources of Freshwater

Sources of freshwater to Sinclair Inlet include direct 

rainfall on Sinclair Inlet, flow of creeks, stormwater flow, 

effluent discharge from wastewater treatment plants, 

groundwater flow, and effluents from dry docks and the steam 

plant on the BNC. Unless freshwater is being imported into or 

exported out of the basin, the sum of creek and groundwater 

discharge should be consistent with the total precipitation 

on the basin minus the losses due to evapotranspiration. The 

groundwater discharge directly to Sinclair Inlet from the 

Sinclair Inlet basin outside of the BNC is not known. 
Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet 19

Table 1. Differences in salinity between upper and lower layers from selected sites, Sinclair Inlet, 

Kitsap County, Washington.

[Station: SIN001, WADOEb, accessed July 12, 2012; CENTER, Gartner and others, 1998. Median salinity values:

SalUL, salinity in upper layer; SalLL, salinity in lower layer. NA, not applicable]

Station

Month

of sample

collection

Number 

of 

samples 

Median salinity values 1- (SalUL/SalLL)

Upper layer

(SalUL)

Lower layer

(SalLL) Difference Annual average

Annual 

deviation

1991–2005

SIN001 All 142 29.30 28.91 1 0.48 2 0.020 2 0.008

Dry Season

CENTER September 2 29.70 29.60 0.10 NA NA

SIN001 May to October 73 29.11 29.46 10.60 NA NA

Wet Season

CENTER March 7 30.07 29.51 0.56 NA NA

SIN001 November to April 68 28.44 29.00 10.36 NA NA

1

The median of the salinity difference of paired near-surface and at-depth values for each sampling event. 

2Data from 2002 to 2005 were not used because three or more months of data were missing.

Atmospheric Deposition

The 118±17 cm/yr of precipitation for water years 

2002–04 (Bob Johnston, U.S. Navy, written commun., 2012; 

ENVironmental inVESTment Project, 2006) falling on the 

8.37 km2 of Sinclair Inlet amounted to an average freshwater 

input of 0.31 m3/s (table 2, fig. 6). 

Freshwater Discharging to Greater Sinclair Inlet

Where possible, freshwater flow estimates were used for 

the period of the ENVVEST project (water years 2002–05). 

Although annually averaged freshwater flows are used, all 

sources of freshwater are presented as cubic meters per 

second. Annual average discharge estimates from the Sinclair 

Inlet creek basins (1.51 m3/s) and flow estimates from 

stormwater drains (0.092 m3/s) were from the output of the 

calibrated ENVVEST project Hydrologic Simulation ProgramFORTRAN (HSPF) model (Skahill and LaHatte, 2007). The 

average estimated discharge of the creeks to greater Sinclair 

Inlet was estimated to be 0.75 and 2.11 m3/s for the dry and 

wet periods, respectively. Precipitation falling on the 86.3 km2

creek and stormwater drainage basins of greater Sinclair Inlet 

can be transported to Sinclair Inlet, lost to evapotranspiration, 

infiltrated into the soils, and transported directly to Sinclair 

Inlet as groundwater, or be diverted to wastewater treatment 

plants in combined sewer-stormwater systems. The water 

yield (length/time) was calculated by dividing the total annual 

flow (length3/time) of the stream and stormwater drain basins 

by their respective area (length2). If all the precipitation 

falling on the basins was transported to Sinclair Inlet, the 

water yield would equal the precipitation after applying the 

appropriate conversion factors. The average annual discharge 

of 1.51 m3/s for creek basins translates into a water yield 

of 64 cm/yr compared the 117 cm/yr of precipitation. Thus, 

about one-half of the rain water falling on stream basins is 

lost to evapotranspiration or to groundwater discharge to 

Sinclair Inlet, with a minor amount being lost to combined 

sewer-stormwater systems. For stormwater basins, the water 

yield was 24 cm/yr of water, with diversion to combined 

sewer-stormwater systems being of greater importance than 

for stream basins. 

The annual average flow rate of the City of Bremerton 

wastewater treatment plant was 0.22 m3/s, much of which is 

imported from outside the Sinclair Inlet drainage basin. In 

2009, the City of Bremerton completed a Combined Sewer 

Overflow (CSO) program, which reduced CSOs by 99 percent 

(City of Bremerton, 2012). The separation of sanitary pipes 

from stormwater drains will decrease the flow from the 

wastewater treatment plant and increase the flows from 

stormwater basins. The West Sound Utility District wastewater 

treatment plant discharges to the mixing zone outside the 

boundary of the domain of this box model. Additional 

knowledge about mixing is required before sources added to 

the mixing zone can be accurately included in a mass balance 

model (Cokelet and Stewart, 1985). 
20 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table 2. Freshwater discharge, freshwater yields, and loadings of suspended solids to and from Sinclair Inlet, Kitsap County, 

Washington.

[Source of data: Wet deposition, water flow of stormwater drains and creeks, Skahill and LaHatte, 2007; flow and TSS from Bremerton Waste Water 

Treatment Plant, Patric Coxon, City of Bremerton, written commun., 2008; 2008 steam plant flows, Bruce Beckwith, U.S. Navy, written commun., 2008. 

Abbreviations: km2, square kilometer; m3/s, cubic meter per second; cm/yr, centimeter per year; mg/L, milligram per year; PSNS & IMF, Puget Sound 

Naval Shipyard and Intermediate Maintenance Facility; PSNS015, the largest stormwater drain on the base, TW, temporary well; TSS, total supsended 

solids; NA, not applicable; ND, not determined; ±, plus or minus; >, greater than; >>, much greater than]

Source Area 

(km2

)

Annual average

discharge

(m3

/s) Water 

yield

(cm/yr)

Total suspended 

sediment

 (mg/L)

Annual 

loading

(metric 

tons per Water year)

Standard 

deviation Freshwater Median Range

Sources

Advection from Puget Sound NA 98 NA NA 0.7 ND 2,100

Atmospheric

Wet 8.37 0.31 0.04 0.31 118 NA NA NA

Dry 8.37 NA NA NA ND ND ND

Watersheds

Storm drains 12.3 0.092 0.005 0.09 24 ND ND ND

Creeks 74.0 11.51 0.04 1.51 64 ND ND ND

Bremerton Waste Water Treatment Plant 2 NA 0.22 0.01 0.22 NA 7.5 5–13 56

Total NA 1.82 >>56

Bremerton Naval Complex

Zone of direct discharge 0.10

 Groundwater 0.006 0.0013 NA NA 1.20 0.2–9.4 NA

 Stormwater 0.0006 0.0001 0.0006 NA NA NA NA

 Steam plant 0.0024 0.0024 NA 1.4 0.73–1.45 0.09

Vicinity of site2 30.43

 Groundwater 0.0002 NA

 PSNS015 

 Freshwater 0.010 0.0007 0.010 80 222 ND

Tidal flushing 0.039 NA 2.15 1.35–2.86 2.7

Capture zone of sumps 0.99

 Stormwater 0.0083 0.0006 0.008 97 35.53–158 ND

 Dry docks 0.36 0.03 4 0.093 NA 0.85 0.16–43.6 8

Total for Bremerton naval complex 1.52 0.115 >11

Total sources 98 2.29 ± 0.07 >>2,170

Sources discharging to passages with Puget Sound (unknown amount of flow and solids entering Sinclair Inlet)

 West Sound Utility District2 0.072 0.002 15 4.7–41 32

Sinks

Advection to Puget Sound 100 2.19 0.63–12.3 6,900

Average sediment deposition from the 1960’s to 2000’s.

Bremerton naval complex 1,620

Greater Sinclair Inlet 5,570

Total sedimentation 7,190

Total sinks 14,100

1Based on 2.11 ± 0.01 m3

/s for the 7-month wet season and 0.75 ± 0.16 m3/s for the 5-month dry season.

2Solids loading based on monthly average total suspended solids data.

3 Includes shoreline area between the PSNS015 stormwater drain and the western end of the seawall.

4Based on a salt balance using dry dock salinity from Huffman and others (2010) and Sinclair Inlet salinity from ENVVEST, 2006.
Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet 21

Freshwater Sources from Bremerton Naval Complex

The sources of freshwater from the BNC include 

discharge from groundwater, stormwater drains, the steam 

plant, and part of the discharge from the dry docks. The 

net flux of groundwater on the western portion of the BNC 

to Sinclair Inlet was estimated to be 0.00623 m3/s in the 

USGS numerical model (Prych, 1997). For comparison, the 

mid‐range estimate of groundwater flux from OU A to Sinclair 

Inlet was 0.0066 m3/s using Darcy’s law calculations based 

on measured shoreline hydraulic gradients and hydraulic 

conductivities, and approximated discharge areas (U.S. 

Navy, 1995a). The groundwater flux estimate from USGS 

groundwater numerical flow model of Prych (1997) is 

constrained by upland recharge, and the flux estimates of the 

U.S. Navy bracket the model estimate, so a net groundwater 

flux of 0.0062 m3/s was used to estimate the associated 

mercury flux. For the purposes of this water balance, 

0.006 m3/s is assigned to the Zone of Direct Discharge, 

and 0.0002 m3/s is assigned to the Vicinity of Site 2. A 

comprehensive error evaluation was not completed with 

the USGS groundwater flow model (Prych, 1997), although 

the author did present information to allow reasonable error 

estimates for the simulated direct discharge of groundwater 

to Sinclair Inlet from the model area. The simulated total 

combined (fresh and Sinclair Inlet water) discharge to the 

dry docks was within 4 percent of the discharge based on 

measurements made in 1994. It would be reasonable to infer 

that the error in the simulated direct discharge of groundwater 

to Sinclair Inlet would be similar. The relative percent 

difference of simulated direct discharges of groundwater to 

Sinclair Inlet using different prescribed boundary conditions 

(no-flow and specified-head boundaries) was 26 percent. 

tac11-0637_fig06

Zone of direct discharge

Vicinity of site 2

Capture zone of sumps

Freshwater

Brackish water

Saline water

EXPLANATION

Zones

Puget Sound Naval Shipyard and 

stormwater drain number

IMF Intermediate Maintenance Facility

1.51

PSNS

Flow, in cubic meters per second

Atmospheric 

wet deposition

0.31

Creeks

1.51

Dry docks

0.36

Seawater

0.27

Stormwater

drains

0.092

Wastewater

0.22

Groundwater

0.006

Stormwater

0.0006

Steam plant

effluent

0.0024 Groundwater

0.0002

PSNS&IMF

Stormwater

0.0083

Ambient groundwater

0.083

Process water

0.010

PSNS015

Fresh

stormwater

0.010

PSNS015

Seawater

0.039 PSNS015

Tidal flushing

0.05

98

100

Mixing

in pipe

Flow of water recycled in and out of 

Bremerton naval complex

Net advective transfer (saline water)–not to scale

Sinclair Inlet

Puget Sound

To dry

dock

Figure 6. Flow of freshwater, seawater recycled into and out of Bremerton naval complex, and net advective transfers 

between Sinclair Inlet and Puget Sound, Kitsap County, Washington.
22 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Groundwater flow simulated by a model with the correct (but 

unknown) boundary conditions should be between those two 

estimates. Combined, those two sources of error are estimated 

to be about 20 percent (0.0013 m3/s).

Flows from smaller BNC stormwater drains in the zone 

of direct discharge (0.0006±0.0001 m3/s), capture zone of 

the sumps (0.0083±0.0006 m3/s), and the large PSNS015 

stormwater drain (0.010±0.0007 m3/s) were taken from the 

ENVVEST project HSPF model (Skahill and LaHatte, 2007). 

In 2008, the freshwater flow from the steam plant equipped 

with an ion-exchange demineralizing system was 0.0024 m3/s 

(Bruce Beckwith, U.S. Navy, written commun., 2008). 

The seepage of the seawater into the sump drainage 

system of the dry docks resulted in salinities of discharge 

water ranging between 17.7 and 24.4 (Huffman and others, 

2012). Water discharged to Sinclair Inlet from the dry dock 

relief drainage systems includes fresh groundwater, additions 

of freshwater from naval operations, and seawater seeping 

into the sumps either directly or through the aquifer. A mass 

balance of salt can be used to calculate the percentage of 

discharge water that is fresh. Knowing the salinity of dry 

dock discharge (SDD) and the salinity of the Sinclair Inlet (SSI) 

seeping into the dry docks, the volume fraction of saltwater 

(FSW) in the dry dock discharge samples that were collected 

was calculated according to the following equation:

F S /S . SW DD SI = (3)

The volume fraction of freshwater (FFW) can be similarly 

calculated by difference:

F 1 S / S . FW = − DD SI (4)

The salinity value of 28.96 was used for SSI

(ENVironmental inVESTment Project, 2006). During normal 

operations when cooling water from a dry docked ship was not 

being discharged into the sump of pump 6, FSW were between 

61 and 84 percent for the dry docks samples, respectively. The 

freshwater flows were 0.032 and 0.061 m3/s from Dry Docks 

1–5 and 6, respectively. Similarly, Prych (1997) calculated 

freshwater flows of 0.025 and 0.054 m3/s, respectively. The 

average annual flows of fresh process water discharged to the 

sumps were 0.0075 and 0.0023 m3/s from Dry Docks 1–5 and 

6, respectively. (Mark Wicklein, U.S. Navy, written commun., 

2012). A total of 0.27 m3/s of seawater was recycled through 

the dry docks. 

Net Advective Transport across the 

Seaward Boundary

Tidal currents that slosh back and forth across a vertical 

plane, such as the cross section of the cable area seaward 

boundary of Sinclair Inlet (fig. 2), do not necessarily transport 

contaminants into or out of the estuary, but can transfer 

contaminants away from areas of elevated concentrations 

by dispersion. In the absence of a horizontal concentration 

gradient of a contaminant caused by large contaminant 

sources, contaminants can be moved into and out of 

the estuary by an advective flow. In classical estuarine 

circulations, heat from the sun and freshwater delivered to 

the upper layer of an estuary stratifies the water column of 

an estuary and drives advective flow out of the estuary in the 

fresher upper layer. The flow of salt out of the estuary in the 

upper layer must be replaced with inflow of saltier water in 

the lower layer; otherwise, the estuary would become a wide 

freshwater river. Because the advective flow is a small net 

residual current between the much larger incoming flooding 

and outgoing ebbing tidal currents, verification of the net 

residual current requires an order of magnitude greater 

scientific effort than only measuring tidal elevations and 

currents. A variety of methods are used to calculate advective 

flow, all of which require extensive field measurements 

for verification. The common approaches to calculate net 

advective flow across the seaward boundary are (1) deploying 

field instrumentation to directly measure current speeds over a 

time period sufficiently long enough to provide the statistical 

power to measure a small difference between two large 

numbers (Noble and others, 2006); (2) simultaneously solving 

the balance of water and salt by measuring freshwater flow 

and the salinity distribution within the estuary over several 

annual cycles (Cokelet and Stewart, 1985); and (3) integrating 

the simulated velocities over the water column derived from 

a baroclinic three-dimensional hydrodynamic model that 

has been field verified for the mass balance of salt and water 

(Khangaonkar and others, 2011). 

The most direct approach of determining net advective 

flows is to measure currents over a period that is representative 

of the hydrologic cycle of the estuarine system. Although 

other transport measurements have been made in Sinclair Inlet 

(Katz and others, 2004), the data record for the 1994 USGS 

deployment (Gartner and others, 1998) is still the only data set 

of sufficient time span to allow calculation of net advective 

transport. Direct long-term measurements of currents in 

Sinclair Inlet were undertaken in 1994 by the USGS during 

6.5 weeks in late winter and 4.5 weeks in summer using 

bottom-mounted acoustic Doppler current profilers (ADCP) 

in which resuspension of bottom sediments was emphasized. 

A bottom-mounted ADCP sends acoustic signals up the water 

column, and water velocities are determined by the Doppler 

shift of returning acoustic signals reflecting off particles 

moving with the water. Although low-pass filtered (30-hour 

moving averages) velocities were reported and discussed 

in Gartner and others (1998), net advective flows and the 

corresponding uncertainties for the entire 1994 current 

velocity data record were not reported. The raw ADCP 

data was obtained from USGS archives and subjected to a 

rigorous quality control evaluation that rejected a significant 

amount of near-surface data (M.A. Noble and others, U.S. 
Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet 23

Geological Survey, written commun., 2012). In this analysis, 

the principle axis of the velocity was determined (65 degrees 

from north), and the velocity data was then transformed to 

along-estuary and across-estuary speeds. The integration of 

the along-estuary current speeds over the depth of lower layer 

determines the transport of water, salt, and contaminants 

into the estuary across a cross section of the estuary (fig. 2). 

Likewise, the integration of the along-estuary speeds over 

the depth of upper layer determines the transport out of the 

estuary. Because of the amount of near-surface data that was 

rejected, the data set for the upper layer is incomplete and the 

balance of water could not be verified. The uncertainties in the 

net along-estuary speed at each depth are large because the net 

advective residual current is a small difference between the 

much larger flooding and ebbing tides. The lag time between 

current measurements for the same depth over which speeds 

are no longer autocorrelated determines the duration of each 

independent measurement, and thus determines the number 

of independent measurements during each deployment. The 

across-estuary current cross section trace that intercepts 

the CENTER site (fig. 2) is divided into two portions with 

currents measured at the CENTER site representing currents 

in the southern half of the cross section. Because the WEST 

site was positioned only 0.5 km west of the cross section, 

currents obtained from the West site are assumed to represent 

the currents in the northern half of the section. The results 

of the ADCP deployments from these two sites and third site 

(EAST), not used in the transport calculation, are detailed 

in M.A. Noble and others, U.S. Geological Survey, written 

commun., 2012. 

During the late winter 1994, the strongest landward 

current speeds in the lower layer (2.2 cm/s) were observed 

at mid-depth at the CENTER site (fig. 7). Integration of 

along-estuary current speeds over the lower layer (eight 

1-m depth intervals in which the net advective current speed 

was significantly greater than zero) yields a transport of 

102± 17.4 m3/s for the southern half of the cross section. In 

contrast, landward current speeds significantly greater than 

zero were observed only in four 1-m depth intervals in the 

lower layer at the West site with strongest net along-estuary 

currents being 0.9 cm/s. Integration of these net advective 

current speeds yields a transport of 18.9±6.8 m3/s for the 

northern half of the cross section. Adding the transport for 

the two halves of the cross section yields a total transport of 

121± 18.7 m3/s for the late winter deployment. Integrating 

over the entire lower layer, regardless of whether the landward 

along-estuary current speed was significant, increases the 

total transport by about 15 percent, but also increases the 

relative error.

In contrast to the late winter deployment, the 

strongest along-estuary current speeds during the summer 

deployment were observed at mid-depth at the West site. 

Integration of along-estuary current speeds over the seven 

1-m depth intervals for which along-estuary current speeds 

were significantly greater than zero yields a transport 

of 60.2± 9.9 m3/s for the northern half of cross section. 

Along-estuary current speeds at the Center site were 

significant only in the bottom two 1-m depth intervals and 

integration of this 2-m depth interval yields a transport 

of 12.8± 7.4 m3/s. For the summer deployment, the net 

advective transport of both halves of the cross section was 

73± 12.4 m3/s. 

There are considerable uncertainties in scaling these 

two observations to annual average transport values needed 

to apply these observations to a mass balance of THg in 

Sinclair Inlet. With only two short ADCP deployments, it 

is not clear if the late winter deployment is representative 

of currents in Sinclair Inlet during wet, windy weather 

conditions typically observed during winter and if the 

summer deployment is representative of currents in Sinclair 

Inlet during dry, calm weather conditions typically observed 

between July and October. Besides weighting errors in scaling 

these two observations to the 1994 average conditions, the 

issue of interannual variability in transport in the landward 

direction due to oceanic and climatic conditions needs to be 

considered. An average transport of 98±23 m3/s (23 percent 

relative error) will be used as a long-term annual average of 

landward along-estuary transport in the bottom layer, but the 

uncertainty is high because of variable results in 1994, the 

unknown variability during the rest of 1994, and the unknown 

long-term variability. 

The current and modeling studies of Wang and Richter 

(1999) indicate that delayed tidal currents from Dyes Inlet 

set up a clockwise gyre in Sinclair Inlet off the Port Orchard 

Passage. The above calculation of average transport assume 

that net residual current along the southern part of the 

transect A–A cross section trace (fig. 2) is similar to the net 

residual currents at CENTER ADCP site. If the outgoing net 

residual currents along the southern shoreline of Sinclair Inlet 

are lower than those recorded at CENTER ADCP site, then the 

above net transport would be overestimated. The uncertainty 

of transport is higher than the variation between the two 

seasons because of the unknown effect of this clockwise gyre 

on average transport into Sinclair Inlet. 

The net advective transport values during these two 

deployments cannot be verified by balancing water in 

Sinclair Inlet because of the incomplete data set of current 

measurements in the surface layer. Even though the estuarine 

circulation appeared to be driven by long-term winds (M.A. 

Noble and others, U.S. Geological Survey, written commun., 

2012), the balance of salt still needs to be maintained. The 

salt balance of an estuary itself has been used to provide a 

primary check of the net transport into and out of the estuary 

using a form of the Knudsen equation (Knudsen, 1900). 

Knudsen’s equation examines the consistency between 

the dilution of the salt from marine water by means of 

freshwater and the relative flows of saltwater and freshwater. 
24 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Consistency of the net advective flow with field observations 

is assessed by comparing the variables on the left side of 

equation 5 with the variable on the right side:

FW SW FW ( ) ( ) UL LL

FW

SW

UL

Q / Q Q 1 – S / S ,

where

Q is long-term annual average flow of freshwater

into Sinclair Inlet,

Q is the long-term annual net advective transport

of seawater into Sinclair Inlet,

S is the long-t

+ =

LL

erm salinity in the upper layer

weighted by velocity over the depth of the

upper layer, and

S is the long-term salinity in the lower layer

weighted over the depth of the lower layer.

(5)

 The most rigorous application of equation 5 requires 

that long-term annual average SUL and SLL be derived by 

integrating salinity over the cross section weighted by the 

long-term along-estuary speeds as a function of depth (Cokelet 

and Stewart, 1985). Given the variability in profiles of the 

along-estuary current speeds shown in figure 7 and the fact 

that QSW and QFW were not measured simultaneously, a less 

exact application of Knudsen’s equation will be undertaken as 

broad check of the QSW. Additionally, the salinity of bottom 

water must accurately reflect freshwater inputs introduced 

to the passages between Sinclair Inlet and Puget Sound, 

including the freshwater inputs of Dyes Inlet introduced 

by Port Washington Passage and the effluent of the West 

Sound Sewer Utility District introduced to the convergence 

zone (fig. 1). 

tac11-0637_fig07

Along-shore current speed, in centimeters per second

Depth, in meters

Total late-winter flow = 121 ± 18.7 cubic meters Total late-summer flow = 73 ± 12.4 cubic meters

-3 -2 -1 0 1 2 3

14

12

10

8

6

4

2

0

CENTER: Late winter CENTER: Summer

WEST: Late winter WEST: Summer

Along-shore current speed, in centimeters per second

Depth, in meters

-3 -2 -1 0 1 2 3

14

12

10

8

6

4

2

0

Along-shore current speed, in centimeters per second

Depth, in meters

-3 -2 -1 0 1 2 3

14

12

10

8

6

4

2

0

Along-shore current speed, in centimeters per second

Depth, in meters

-3 -2 -1 0 1 2 3

14

12

10

8

6

4

2

0

Transport into Sinclair Inlet in 

bottom layer =102 ± 17.4 cubic 

meters per second (m3

/s)

Transport into Sinclair 

Inlet in bottom layer 

=12.8 ± 7.4 m3

/s

Transport into Sinclair 

Inlet in bottom layer 

= 60.2 ± 9.9 m3

/s

Transport into Sinclair 

Inlet in bottom layer 

=18.9 ± 6.8 m3

/s

Figure 7. Profiles of current with depth at the CENTER and WEST acoustic Doppler current profiler sites during late winter 

and summer 1994, Sinclair Inlet, Washington. Data from M.A. Noble and others, U.S. Geological Survey, written commun., 2012.
Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet 25

The most easily accessible long-term salinity data set 

was obtained by the Marine Monitoring Program of the 

Washington State Department of Ecology (2012b) in which 

the salinities at the depth of discrete surface (nominal depth 

of 0.5 m) and near bottom (nominal depth of 10 m) were 

recorded from a conductivity temperature depth (CTD) 

profile taken from a float plane on a monthly basis (weather 

permitting) at a station just east of BNC-52 (fig. 4). The 

average value of the variable on the right side of equation 

5 for 139 sampling periods between 1991 and 2005 was 

0.018 and ranged between 0.000 (the water column being 

completed mixed) and 0.205 (highly stratified water column 

in January 1995, when the surface salinity was 22.94). The 

monthly values on the right side of equation 5 were averaged 

for 1991–2001. The 10-year average annual value of the right 

side of equation 5 was 0.020± 0.008. 

The long-term variability in the freshwater input on the 

left side of equation 5 is dominated by the variability in the 

annual discharge from creek, shoreline, and stormwater drain 

basins. The monthly discharge simulations from a calibrated 

HSPF model (Skahill and LaHatte, 2007) were averaged 

for each year from 1993 to 2001 for the entire Sinclair 

Inlet drainage basin, yielding an average freshwater flow of 

1.51±0.04 m3/s. Adding the freshwater flows from rainfall, the 

wastewater treatment plant, and the dry dock relief drainage 

systems yield a freshwater flow of 2.29±0.35 m3/s (20 percent 

relative error) for about the same time as the determination of 

the salinity difference, which encompasses the ADCP study. 

Applying the average transport value of 98±23 m3/s for QSW to 

this freshwater flow, yields a value of 0.023±0.006 for the left 

side of equation 2. Given the varying time scales and periods 

of the available data for freshwater flow and marine velocity 

and salinity, a net along-estuary advection transport of 98 m3/s 

seems to be valid within a factor less than 2. 

The net advection of water (QSW) into Sinclair Inlet is 

one of the most important factors controlling the mass balance 

of THg in Sinclair Inlet. The magnitude of QSW dictates the 

amount of THg needed to be discharged to Sinclair Inlet 

to cause a specific increase in THg concentrations relative 

to THg concentrations in Puget Sound water. For instance 

using the best estimate of 98 m3/s for QSW, an increase of 

0.1 ng/L of THg requires that about 300 g of THg be added 

to Sinclair Inlet to balance the mass of THg leaving Sinclair 

Inlet. In contrast, a discharge of about 600 g of THg would 

be required to balance THg for the same increase of 0.1 ng/L, 

if QSW = 200 m3/s. Thus, reducing the uncertainty in QSW is 

required to constrain the mass balance of THg in Sinclair Inlet.

A more exact method of verifying these transport values 

is to vertically integrate the average along-estuary current 

speeds over the cells of a baroclinic three-dimensional 

hydrodynamic model that accommodates wind shear and 

has been constrained by the balance of salt. Johnston and 

others (2009) developed a Curvilinear Hydrodynamics in 

3 Dimensions (CH3D) model to simulate the distribution 

of fecal coliform in Sinclair and Dyes Inlets. The model 

was calibrated using the 1994 USGS tidal current and tidal 

heights; the tidal currents were verified with instantaneous 

measurements of tidal currents made using boat mounted 

ADCPs (Katz and others, 2004), dye tests, and drogue tests 

(Wang and others, 2005). Results of tidal currents and height 

from the model were compared to the 67 day record of current 

measurements from an upward looking ADCP deployed in 

1997 by the U.S. Navy Space and Naval Warfare Systems 

Command (SPAWAR1) near the USGS Center site (Wang and 

Richter, 1999). Following the addition of freshwater flows 

and fecal coliform loading from the watershed, the integrated 

model was verified by simulating short term storms (10 days) 

and comparing model simulation results to measured salinity 

and fecal coliform concentrations at selected locations within 

the model domain. After adjusting the model with finer grid 

sizes in nearshore areas to better represent freshwater mixing, 

the model recreated measured data with acceptable accuracy 

for most of the model domain (Johnston and others, 2009). All 

of the field components needed to constrain a hydrodynamic 

model have been performed between 1994 and 2009, and 

include long-term upward looking ADCP records (1994, 

1997), stream monitoring (2002–05), wind measurements 

(1994, 2002–05), and extensive salinity profiles over the 

annual cycle (1991–2005, 2008–09). However, conducting a 

detailed analysis of all these components to tightly constrain 

the balance of water and salt within Sinclair Inlet was outside 

the scope of this project.

Mass Balance of Solids

In addition to balancing salt in an estuary, the mass of 

solids entering the water column of the estuary from air, land, 

or transported from Puget Sound needs to be balanced with the 

mass of solids leaving the water column of the estuary either 

by sedimentation or in the upper layer flowing to Puget Sound. 

Balancing solids within an estuary is much more challenging 

because various processes, in addition to water advection 

and dispersion, affect solids movement. These processes 

include resuspension, differential settling, flocculation, and 

biological growth. 

Sources of Solids

Without knowing the origin of particles that settle in the 

sediment column, the relative contribution of the mass of a 

constituent from different sources in the sediment is unknown. 

Although sand and clay particles are essentially conserved in 

an estuary, the production of biological organic matter and the 

decay of biological detritus can introduce errors in the mass 

balance of solids. However, the small loss of organic matter 

by remineralization (6 weight percent organic matter in the 

sediments of Sinclair Inlet from the U.S. Navy, 2006a, 2006b, 

and 2008b) will contribute only a small error to the mass 

balance of solids in Sinclair Inlet. 
26 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Puget Sound Sources of Solids

The advection of solids into Sinclair Inlet from Puget 

Sound requires knowledge of the net advective transport 

from, and average concentrations of TSS, in Puget Sound. 

The coarse bed sediments in Rich and Port Orchard Passages 

suggest that few particles settle in these passages. The TSS 

concentration of 0.7 mg/L for Puget Sound (Paulson and 

others, 1988) was used to derive an advective transport of 

2,100 metric tons per year of solids to Sinclair Inlet from 

Puget Sound. The higher average TSS concentration of 2 mg/L 

for Puget Sound collected at two stations by King County 

Department of Natural Resources and Parks (2001) in Puget 

Sound was obtained by methods thought to be biased high 

(Battelle Duxbury, 1998). 

Solids Discharging into Greater Sinclair Inlet

Because the ENVVEST project HSPF model was not 

calibrated for TSS transport, the loading of TSS from creek 

and stormwater basins is not known. Empirical calculations 

that do not properly weight the high flow events, when 

most solids are discharged to estuaries, are likely to grossly 

underestimate the total loadings. The sources of solids that 

have not been quantified in this study include: the creek basins 

of Sinclair Inlet; stormwater from inside and outside of the 

BNC (except tidal flushing of the storm drain PSNS015); 

bed transport from the convergence zone; suspended and bed 

transport from Dyes Inlet; landslide and shoreline erosion 

within Sinclair Inlet and its approaches from Puget Sound 

(Rich and Port Orchard Passages); and dry deposition. Without 

the quantification of solids from the stormwater and creek 

basins, there is an incomplete understanding of solids sources 

and sinks and there is a limited comparison of the quantifiable 

solids loadings among a few quantifiable sources (municipal, 

industrial and Puget Sound sources) with quantifiable loadings 

among sinks (sedimentation and advection to Puget Sound). 

Municipal and industrial sources of suspended solids 

include the City of Bremerton Wastewater Treatment Plant, 

the BNC steam plant, and the two dry dock discharge systems. 

The daily flow-weighted, composited TSS values from the 

treatment plant were multiplied by the daily flows from the 

plant to derive daily TSS loadings (Patric Coxon, City of 

Bremerton, written commun., 2008), which were summed 

and averaged for water years 2002–04 to produce an average 

annual TSS loading of 56±4 metric tons per year. 

Solids Discharging from Bremerton Naval Complex

In 2008, USGS measured TSS (Huffman and others, 

2012) in grab samples of effluent from the steam plant 

(number of samples [n]=4) and dry dock systems (n=11). 

These grab samples collected during a given time in the 

pumping cycle may not reflect the average conditions during 

the pumping cycle. Additionally, the results from the limited 

number of samples do not reflect the range of activities that 

occur throughout the year. The median TSS concentration in 

the steam plant effluent in 2008 was 1.4 mg/L (range: 0.47 to 

1.52 mg/L), which results in an estimated load of 0.09 metric 

tons per year. The median TSS concentrations in samples 

collected from the discharge pipe of dry docks was 0.85 mg/L 

and ranged between 0.16 and 43.6 mg/L (table 2). The 

exceptionally high TSS concentration of 43.6 mg/L, compared 

to the next highest TSS concentration of 1.47 mg/L, was 

measured on June 24, 2008. At the time of the June sampling 

(10:30 a.m. PDT), two unusual activities were occurring in 

the dry dock system (Bruce Beckwith, U.S. Navy, written 

commun., 2008): (1) repairs were being made to the drainage 

system that may have stirred up accumulated sediments, 

and (2) concrete was being cut in one of the dry docks using 

cooling water on the cutting blade. If exceptionally high 

TSS concentrations were still present in the afternoon, it 

is likely that the total copper concentration in an unfiltered 

sample collected by the U.S Navy at the 2:30 p.m. would 

have exceeded the detection limit of 10 μg/L. No copper was 

detected in the 2:30 p.m. sample, suggesting that the morning 

drainage repairs, the concrete cutting operation, or both were 

the probable cause for the temporary high TSS in the USGS 

sample collected in the morning. Using a median value of 

0.84 mg/L for the TSS concentration and average operating 

flow conditions, the loading of solids to Sinclair Inlet from 

the Dry Dock 1–5 relief drainage system was about 4 metric 

tons per year. Likewise, a median value of 0.71 mg/L from the 

sump for Dry Dock 6 resulted in a solids loading of 4 metric 

tons per year. 

As described in the water budget, between 61 and 

84 percent of the water discharged by the dry dock pumps 

is seawater from Sinclair Inlet. Thus, much of the estimated 

8 metric tons per year of solids discharged from the dry 

dock drainage system may have originated in Sinclair Inlet 

rather than from naval operations or groundwater seepage. 

However, the portion of solids originating from Sinclair 

Inlet cannot be quantified because there are no data on the 

efficiency of particle trapping along the flowpath from Sinclair 

Inlet to pump system sumps. Although solids are detected in 

monitoring wells, it is thought that particles are efficiently 

trapped along the flow path to the estuary in all but the 

coarsest soils. Thus, no solids are assumed to originate from 

groundwater flow. 

During each of the relatively dry-period sampling events 

of the PSNS015 stormwater drain during ebbing tidal cycles 

on December 29, 2010, and March 31, 2011, TSS samples 

were obtained from timed-average composite samples 

collected during the sampling periods. The TSS concentrations 

were 1.35 and 2.86 mg/L, respectively. Integrating the average 

TSS concentrations over the 1,770 m3 that flowed to Sinclair 

Inlet during the March 31, 2010, sampling event, yields a 

discharge of 3.7 kg per tidal cycle. Scaling the median value 

up for the two tidal cycles each day over the year yields an 

estimated annual TSS loading of 2.7 metric tons of solids 

discharge from tidal flushing. 
Mass Balance of Water, Salt, and Total Suspended Solids in Sinclair Inlet 27

Sinks for Solids

The primary sinks for solids in Sinclair Inlet are 

sedimentation and advection to Puget Sound. The estimated 

sedimentation of solids on a dry weight basis is described in 

detail in appendix B and calculated in table B1. This method 

results in an estimated sedimentation of 1,620 metric tons per 

year in the OU B Marine and 5,570 metric tons per year in 

greater Sinclair Inlet for a total of 7,190 metric tons per year 

for the Sinclair Inlet model domain.

Another sink for solids is advection from Sinclair Inlet to 

Puget Sound. The median concentration of TSS in the upper 

layer at the greater Sinclair Inlet stations (table 3) between 

August 2008 and August 2009 was 2.19 mg/L (range: 0.63 

to 12.27 mg/L). Using the estimated seaward along-estuary 

net advection flow of approximately 100 m3/s out of Sinclair 

Inlet in the upper layer translates into a possible net export 

of 6,900 metric tons of solids. Because suspended solids 

can settle in Sinclair Inlet and particulate organic matter can 

decompose in the water column and at the sediment-water 

interface, not all the estimated 6,900 metric tons of solids 

transported in the upper layer of Sinclair Inlet may be leaving 

Sinclair Inlet. The surface layer in the convergence zone is 

highly influenced by the outflow of water from Sinclair Inlet 

and Dyes Inlet through Port Washington Narrows (fig. 1). 

The TSS concentrations at the convergence zone can be used 

to assess the loss of TSS in upper layer. The median TSS 

concentration in the upper layer of the convergence zone 

(1.91 mg/L) is slightly lower than the median concentration 

in upper layer of greater Sinclair Inlet (2.19 mg/L). The 

similarity in the TSS concentrations in greater Sinclair Inlet 

and the convergence zone indicates that little TSS is lost in 

the convergence zone and the Dyes Inlet-Sinclair Inlet system 

is a net exporter of TSS to the central basin of Puget Sound, 

presumably as smaller size solids. 

Table 3. Total suspended solids, filtered total mercury, and total mercury of suspended solids from five categories of the marine water 

samples from Sinclair Inlet, Kitsap County, Washington, 2008–09.

[Multi-comparison category: Post-anova Tukey tests. Abbreviations: mg/L, milligram per liter; ng/L, nanogram per liter; mg/kg, milligram per kilogram; OU, 

operable unit]

Sample category

Total suspended solids (mg/L) Filtered total mercury (ng/L)

Number 

of 

samples

Mean Standard

deviation Median Range

Number 

of 

samples

Mean Standard

deviation Median Range

OU B marine lower layer 14 9.54 26.41 2.38 1.13–101.2 13 0.31 0.14 0.25 0.21–0.72

OU B marine upper layer 20 2.14 1.35 1.87 0.7–6.05 21 0.33 0.12 0.31 0.04–0.572

Convergence zone 12 1.88 0.63 1.91 0.72–2.95 12 0.30 0.06 0.31 0.18–0.41

Greater Sinclair Inlet 

lower layer

16 2.40 0.93 2.32 0.92–4.06 12 0.45 0.23 0.36 0.22–0.97

Greater Sinclair Inlet 

upper layer

27 3.05 2.81 2.19 0.63–12.27 28 0.39 0.16 0.33 0.22–0.87

Station category

Total mercury of solids (mg/kg)

Number 

of 

samples

Mean Standard

deviation Median Range

Multicomparison

 category

OU B marine lower layer 14 0.45 0.28 0.40 0.01–1.02 A

OU B marine upper layer 22 0.23 0.13 0.18 0.07–0.56 B

Convergence zone 12 0.29 0.12 0.25 0.12–0.49 B

Greater Sinclair Inlet 

lower layer

16 0.32 0.15 0.37 20.09 –0.57 B

Greater Sinclair Inlet 

upper layer

29 0.23 0.17 0.17 0.066–0.72 B

1 Does not include the concentration of targeted BNC-39 sample collected on June 2, 2009.
28 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Rationale for Separate Mass 

Balances of Dissolved and 

Particulate Mercury in 

Sinclair Inlet

The data on streamflow, salinity distribution 

in Sinclair Inlet, and 1994 ADCP current 

measurements, coupled with the hydrodynamic 

baroclinic model, constrain the uncertainty of 

the net advective transport across the seaward 

boundary of the model domain to an extent useful 

for pursuing the mass balance approach for FTHg. 

However, the sum of the quantifiable sources of 

TSS from watersheds (56 metric tons per year) and 

the Bremerton naval complex (11 metric tons per 

year) amounts to less than 1 percent of the mass 

of solids depositing in sediments of Sinclair Inlet 

(7,190 metric tons per year). This discrepancy is 

compounded because the Sinclair Inlet appears to 

be a net exporter of solids to Puget Sound. Without 

a better understanding of the sources of solids 

that settle in Sinclair Inlet, efforts to balance the 

sources of mercury with a significant sediment sink 

likely will be unsuccessful.

To maximize the usefulness of the available 

data in understanding the environmental effects 

of present day sources of THg to Sinclair Inlet 

on THg concentrations in the water and sediment 

column, the THg in the water and particle phases are 

examined separately. This approach previously has proven 

useful in understanding the fate of trace metals in Puget 

Sound (Paulson and others, 1988) and separating dissolved 

and particulate mass balances of THg is justified if the rate 

of conversion between FTHg and PTHg is small compared 

to the sources and transport rates. If this conversion of THg 

between the aqueous and particulate phases is small, then 

THg can be assumed to be what estuarine scientists call 

“essentially conservative.”

Extensive studies support this approach of developing 

separate mass balances for aqueous and particulate THg. 

In San Francisco Bay, California, the seasonal variation of 

FTHg concentrations were attributed to temporal changes in 

sources (Choe and others, 2004) and FTHg concentrations 

were not affected by phytoplankton bloom growth or decay 

(Luengen and Flegal, 2009). The seasonal variation in FTHg 

concentrations at four stations in Sinclair Inlet between 

tac11-0637_fig08

EXPLANATION

BNC-52

CZ

SI-IN

SI-PO

Filtered total mercury, in nanograms per liter

0

0.2

0.4

0.6

0.8

1.0

2008 2009

Only evidence of 

removal of FTHg

Aug. Sept. Oct. Nov. Jan. Feb. Mar. May June July Aug. Apr.

Stations

Figure 8. Concentrations of filtered total mercury in near-surface water 

collected from four stations in Sinclair Inlet, August 2008– August 2009.

August 2008 and August of 2009 as part of the Methylation 

and Bioaccumulation Project (Huffman and others, 2012) 

(fig. 8) were examined for similarities to the behavior of FTHg 

concentrations in San Francisco Bay. Occasional elevated 

FTHg concentrations are superimposed on a steady baseline 

of FTHg that is consistent among Sinclair Inlet stations. 

The steady baseline of FTHg in Sinclair Inlet indicates that 

the rate of conversion from FTHg to PTHg is small relative 

the transport of FTHg from Puget Sound. The only strong 

indication of depletion of FTHg was indicated in one sample 

(BNC-52) in July 2009 during a period of high productivity 

(chlorophyll a concentration of 19 μg/L, Huffman and others, 

2012). The occasional elevated FTHg concentrations over 

the baseline probably are a temporary consequence of local 

sources. The decline in the baseline of FTHg during the 

autumn 2008 bloom period is relatively small and could be a 

result of a small conversion from FTHg to PTHg or decreasing 

inputs of FTHg. 
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 29

Sources and Sinks of Filtered Total 

Mercury to Sinclair Inlet

FTHg discharged from non-BNC watershed originates 

primarily from precipitation, leaching of soils, and non-point 

releases from residential and commercial uses of mercury 

products. Non-point releases include improper outdoor 

disposal of thermostats, automotive switches, fluorescent 

lamp disposal, and mercury cell batteries (Washington State 

Department of Ecology and King County, 2011). The Record 

of Decision for OU B Marine (U.S. Environmental Protection 

Agency, 2000) identified three primary modes of THg 

transport from the BNC that have a potential to recontaminate 

marine sediment that have undergone remediation. These 

pathways include submarine groundwater discharge 

directly to Sinclair Inlet, discharges from BNC industrial 

outfalls (primarily the dry dock sump and the steam plant 

discharges), and discharge through BNC stormwater systems. 

Quantification of the loadings of filtered total mercury from 

sources outside of the BNC is reported to put the BNC 

loadings into environmental perspective. 

Concentrations of Filtered Total Mercury

 Generally, the mass of a source or sink is calculated by 

multiplying the median FTHg concentration for a source by 

its annual flows. In the case of the BNC dry dock discharges 

and the tidal flushing of stormwater drain PSNS015, the net 

mass is calculated to account for the recycling of Sinclair Inlet 

seawater into BNC structures. The mass of FTHg added from 

the atmosphere and sediment is calculated by multiplying a 

flux by the area of Sinclair Inlet. 

Seawater Transported to Puget Sound

The median concentration of FTHg in the upper layer of 

marine water in greater Sinclair Inlet measured in this study 

was 0.33 ng/L (table 3). The mean value of 0.89 ng/L for 

29 measurements of FTHg+PTHg by USGS was similar to 

the mean value of 1.09 ng/L for 17 measurements of WTHg 

by the ENVVEST project (table C1). The mean, median, and 

maximum values of WTHg measurements by the ENVVEST 

project that focused on storm events were higher than 

comparable values of FTHg+PTHg monthly measurements 

by USGS.

Water Discharged to Greater Sinclair Inlet

Although this report focuses on sources of FTHg in 

waters discharged from the BNC, FTHg was measured in 

effluents of wastewater treatment plants, stormwater, and 

streams in the Sinclair Inlet basin in 2008 and 2009 outside of 

the BNC as part of a companion methylmercury survey. FTHg 

discharged by the streams, stormwater drains, and wastewater 

treatment plants originate from rainfall on the landscape of 

Sinclair basin, leaching of THg from soils to groundwater, 

and use of mercury by industry, commerce, and a variety of 

consumer products households within the basin. 

Although THg in wet precipitation samples includes a 

small amount of particulate THg scavenged by precipitation, 

wet deposition of WTHg was assumed to be filterable (FTHg). 

Since streamflow and stormwater originates from rainwater, 

the average concentration of 5 ng/L of WTHg in rainwater can 

be compared to FTHg concentrations in freshwater sources. If 

FTHg concentrations in freshwater sources are considerably 

less than 5 ng/L, then a portion of WTHg in the rainwater 

has been scavenged between the time rainwater falls on the 

pervious and impervious land surfaces and the water enters 

a creek or storm drain. Likewise, if FTHg concentrations 

are considerably greater than 5 ng/L, then FTHg mercury 

has been added to the original rainwater through leaching 

from soils or from anthropogenic sources. This comparison 

of concentrations is a simplified comparison of atmospheric 

deposition of THg (M L-2 T-1) with basin yields of FTHg 

([M T-1]/L-2).

Creek Basins

Water from four creeks (Blackjack, Anderson, Annapolis, 

and Gorst Creeks) within the Sinclair Inlet basin and Olney 

Creek (fig. 2) was sampled in May and July 2008, but the 

July data are qualified as estimated. Streamflow discharges in 

May and July differed by less than 20 percent, except that the 

discharge of the smallest creek sampled (Annapolis Creek) 

in July was one-quarter of the discharge in May. The median 

FTHg concentration in creek water was 0.57 ng/L and ranged 

between 0.39 and 0.81 ng/L (table 4). The concentrations of 

FTHg in creek water collected during dry weather base flow 

were significantly less than WTHg concentrations in rainfall 

indicating that the basins retained a significant portion of the 

atmospheric THg in their soils. The sums of FTHg+PTHg 

concentrations for the May and July 2009 sampling (table C1) 

were comparable to or slightly less than the range of THg of 

unfiltered water collected by the ENVVEST project during dry 

base flow in September 2002 (ENVironmental inVESTment 

Project, 2006). 
30 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table 4. Concentrations and loadings of filtered total mercury for Sinclair Inlet, Kitsap County, Washington.

[Category: I, less than 1 gram per year; II, single digit grams per year; III, tens of grams per year; IV, hundreds of grams per year. Abbreviations: km2, square 

kilometer; m3/s, cubic meter per second; ng/L, nanogram per liter; g/yr, gram per year; GW, groundwater; PSNS&IMF, Puget Sound Naval Shipyard and 

Intermediate Maintenance Facility; DD, dry dock; FTHg, filtered total mercury; NA, not applicable; <, less than; –, not determined]

Source Area

(km2

)

Flow

(m3/s)

Number 

of 

samples

Filtered total mercury

Concentration (ng/L) Loading (g/yr) Category

Median Range Median Range

Exchange from Puget Sound by difference – – – – – 420 200–800 NA

Advection from Puget Sound NA 98 40 0.20 <0.1–0.6 620 – NA

Advection to Puget Sound NA 100 – 0.33 – 1,040 – NA

Direct atmospheric deposition 8.37 0.31 – 4.75 2.16–11.3 34.6 – III

Greater Sinclair Inlet 86.3 1.82 – – – 48.9 – NA

Creeks 74.0 1.51 10 0.57 0.39–0.81 27.1 24.2–34.2 III

Stormwater 12.3 0.093 3 4.25 4.02–4.62 12.3 11.6–13.4 III

Municipal effluent NA 0.22 3 1.38 1.06–1.55 9.5 7.3–10.7 II

Bremerton navel complex sources 1.52 0.43 NA NA NA 146+Capture 

Zone GW

– NA

Zone of direct discharge 0.10 0.009 NA NA NA 6.74 – NA

Groundwater NA 0.006 10 1

4.06 21.4–6 10.81 20.3–1.2 I

Stormwater NA 0.001 0 3

1.83 1.5–2.16 0.03 0.03–0.04 I

Steam plant NA 0.002 4 78 15.5–143 5.9 1.2–12 II

Vicinity of Site 2 0.43 0.049 NA NA NA 120.2 – NA

Groundwater NA 0.0002 5 194 72–702 1.2 0.6–2.5 II

PSNS015 Stormwater drain NA 0.049 NA NA NA 119 – IV

Freshwater NA 0.010 1 144 NA 46 – NA

Tidal flushing NA 0.039 1 458.8 NA 73 – NA

Capture zone of sumps 0.99 0.368 NA NA NA 18.8+GW – NA

PSNS&IMF stormwater NA 0.0083 2 1.83 1.50–2.16 0.48 0.39–0.57 I

Dry Docks NA 0.36 NA NA NA 18.3 – III

DD 1-5 NA 0.16 7 11.36 20.63–4.16 6.9 23.2–26 NA

DD 6 NA 0.20 4 11.81 20.97–2.38 11.4 28.2–13.9 NA

Groundwater NA unknown 10 2.62 1.07–31 Thought to be minimal, but site 10C

and 10E need further investigation

Diffusion from marine sediments 8.37 NA 24 9.30 5.07–25.2 100s 100s IV

Total Sinclair Inlet sources – – – – – 230+100s – –

1

Using concentrations of filtered total mercury from Wisconsin Mercury Research Laboratory.

2

Range calculated from median by setting non-detectable values from the National Water Quality Laboratory to 0 and to 6 ng/L.

3

Using FTHg concentrations from PSNS&IMF stormwater.

4

Flux-weighted average during the March 31, 2010, ebb cycle.
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 31

Stormwater

Navy City stormwater drain in Gorst (fig. 4) was 

sampled at low tide during a heavy storm event on January 7, 

2009, resulting in a specific conductance measurements 

of 74 μS/cm and a FTHg concentration of 4.25 ng/L. The 

stormwater drains near Sheridan Road (fig. 1) and near the 

boat ramp of the Port Orchard Marina (fig. 4) were sampled 

at low tide the following evening (January 8, 2009) as the 

trailing edge of the storm passed, resulting in values of specific 

conductance measurements of 20 and 75 μS/cm, respectively, 

and FTHg concentrations measurements of 4.62 and 

4.02 ng/L, respectively. FTHg concentrations in stormwater 

were comparable to those in rainwater and indicate that little 

FTHg is scavenged during storm events similar to the event of 

January 7, 2009. The sum of the FTHg+PTHg concentrations 

in the Navy City stormwater drain (table C1) was within the 

range of WTHg concentrations measured between 2002 and 

2005 (ENVironmental inVESTment Project, 2006). 

Wastewater Treatment Plant Effluents

FTHg and PTHg were measured in May, July, and 

August 2008 from a composite of five grab samples collected 

over the 8-hour day shifts from the wastewater treatment plant 

effluents for the City of Bremerton and West Sound Utility 

District. The median FTHg concentration for the City of 

Bremerton Wastewater Treatment plant (table 4) was 1.38 ng/L 

(range: 1.06 to 1.55 ng/L). USGS THg data collected during 

non-storm periods in the summer of 2008 were less than 

comparable data collected by ENVVEST (ENVironmental 

inVESTment Project, 2006) mainly during storm events 

(table A9). The effluent from the West Sound Utility District 

does not discharge into the Sinclair Inlet model box; results 

are presented only for comparison with the City of Bremerton 

plant. The median FTHg concentration in effluent from the 

West Sound Utility District treatment plant was 2.21 ng/L 

(range: 2.20 to 3.52 ng/L). 

Water Discharged from the Bremerton 

Naval Complex

FTHg discharged to Sinclair Inlet from the BNC 

originates from current naval operations and leaching of 

legacy mercury from contaminated soils by fresh and saline 

groundwater within the BNC. Within the terrestrial boundary 

of the BNC, FTHg is also added from rain falling onto the 

BNC landscape, seepage of seawater from OU B Marine into 

the dry docks, and seepage of ambient fresh groundwater 

entering the landward boundaries of the site.

The USGS collected groundwater samples for FTHg 

analyses from 12 monitoring wells (fig. 4) between 

January and June 2008 to evaluate dispersed and point 

(localized) sources of THg to Sinclair Inlet from groundwater 

beneath the BNC. During the first base-wide sampling event 

(January 28–February 1), FTHg was measured by the USGS 

NWQL. Insofar as FTHg concentrations above the estimated 

level of 6 ng/L were measured in only 3 of the 11 samples, 

FTHg in samples from the second base-wide sampling event 

in April were analyzed by the WMRL that reported FTHg 

concentrations as low as 0.04 ng/L. The USGS also conducted 

more intensive groundwater sampling over selected tidal 

periods during May and June 2008 at wells OUBT-722 and 

OUBT-715R, and at piezometers in the intertidal zone adjacent 

to OUBT-722 (fig. 5 inset). 

Zone of Direct Discharge

Groundwater in western BNC is thought to discharge 

directly to Sinclair Inlet (Prych, 1997). Groundwater 

samples were collected from four monitoring wells in OU A

by the USGS during January and April 2008, and well 

OUBT‐715R was sampled in May 2008. Groundwater from 

well OUA-206 contained freshwater, whereas the four other 

wells contained saltwater. During the April sampling events, 

groundwater levels and salinities were lower than those 

during the January sampling event. Samples collected from 

OU A in January were analyzed by NWQL with the reporting 

level of 10 ng/L, as were the two samples collected from 

OUBT-715R in May. Only the groundwater collected from 

well OUA-241 in January contained a FTHg concentration 

at the reporting level. Calculating median values of data 

sets containing non-detectable concentrations with varying 

reporting levels is problematic (Helsel and Hirsch, 1992). 

In this report, the median value for each data category was 

calculated using only data from the WMRL. The median of 

the four detectable FTHg concentrations collected from the 

Zone of Direct Discharge in April analyzed by WMRL was 

4.06 ng/L (table 5). The lower range of the median FTHg 

concentration of the entire data set is calculated by first setting 

non-detectable values of the NWQL to zero, then calculating 

the median value of the mixed data set. The upper range of 

the median FTHg concentration was calculated by setting 

non-detectable concentrations from the NWQL to the lowest 

estimated concentration reported by NWQL (6 ng/L), then 

calculating the median value for the mixed data set. The 

median for the mixed WMRL and NWQL data set ranged 

between 1.4 and 6 ng/L. Since the reporting level for the least 

sensitive method was 10 ng/L, the frequency of values above 

10 ng/L is a robust non-parametric indicator that can be used 

with mixed data sets to compare FTHg concentrations across 

sample categories. No groundwater sample from the Zone of 

Direct Discharge contained FTHg in excess 10 ng/L. 
32 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

FTHg concentrations below 10 ng/L are consistent 

with the Site Inspection (1990–91), the OU A RI/FS, and the 

Synoptic Study (1998–2002) in which none of 71 filtered 

samples had unqualified detectable concentrations at reporting 

levels between 100 and 200 ng/L (U.S Navy, 1995a). 

Nearly all previous reported high concentrations of WTHg 

(concentrations in micrograms per liter) from OU A wells 

probably were not representative of aqueous phase mercury 

in groundwater that could migrate to Sinclair Inlet because 

excess solids likely were entrained in the water samples 

(appendix A). No localized sources of mercury were identified 

in OU A. 

All steam plant effluent samples contained FTHg 

concentrations above 10 ng/L in 2008 (range: 15.5 to 

143 ng/L). FTHg concentrations were correlated (correlation 

coefficient=0.96, p value=0.04) with specific conductance 

(fig. 9). In 2010, when the steam plant demineralizing process 

changed to a reverse osmosis system, the use of sulfuric acid 

and caustic soda reagents that contained trace amounts of THg 

was discontinued. This change will likely decrease the THg 

concentrations in the effluent.

Vicinity of Site 2

Data from this and several past studies described 

above indicate that Site 2 (fig. 5) is an area of elevated 

THg concentrations in a variety of water and solids for the 

following reasons: (1) soils to 12 m (38 ft) below the site 

contain high THg concentrations ranging between 6.6 and 

31 mg/kg (table A1), (2) high, but questionable, concentrations 

of WTHg were detected in groundwater collected from 

wells, which since have been decommissioned, (3) high 

concentrations of WTHg (65.51–1,131.02 ng/L, table A10) 

were measured in stormwater from drain PSNS015 that 

passes under the site and is tidally connected to the site, and 

(4) high WTHg concentrations (990–6,690 ng/L, converted 

from concentrations in micrograms per liter from table A12) 

in groundwater from well LTMP-3 adjacent to the site were 

measured and have been verified by more sensitive analytical 

methods (1,190 and 3,680 ng/L, table A11). 

In winter and spring 2008 events, USGS collected 

groundwater samples from two monitoring wells adjacent to 

Site 2; OUBT-722 (called LTMP-3 by the U.S. Navy) along 

Table 5. Frequency of filtered mercury concentrations greater than 10 nanograms per liter in samples from the Bremerton naval 

complex, Kitsap County, Washington.

[Source of data: Huffman and others, 2010. WMRL: Wisconsin Mercury Research Laboratory; QA, samples measured by WMRL were collected for 

interlaboratory comparison of NWQL. Mixed WMRL and NWQL data set: NWQL, National Water Quality Laboratory; FTHg, filtered total mercury; 

ng/L, nanogram per liter. Abbreviations: OUBT, Operable Unit B Terrestrial; TW, temporary well; PSNS, Puget Sound Naval Shipyard; IMF, Intermediate 

Maintenance Facility; DD, dry dock; <, less than; –, no data]

Zone

 WMRL Mixed WMRL and NWQL data set

Number 

of 

samples

Median Range

Number 

of 

samples

Frequency 

greater than 

10 ng/L 

(percent)

Median FTHg assuming NWQL 

non-detectable concentrations 

0 ng/L 6 ng/L

Zone of direct discharge

 Groundwater 4 4.06 0.65–8.33 10 0 1.4 6

 Steam plant 4 78.3 15.5–143 4 100 78.3 78.3

Vicinity of Site 2

OUBT-722 3 QA QA 44 100 495 495

OUBT-718 1 0.8 – 2 0 0.4 4

TW-05 5 194 71.2–702 5 100 – –

TW-01 to TW-04 40 1.3 <0.04–9.4 40 0 – –

PSNS 015 stormwater 1 144 – – 100 – –

PSNS 015 tidal flushing 1 QA QA 10 80 41 41

Capture zone of sumps

Fresh ambient groundwater 

(OUNSC-380)

1 1.1 – 2 0 0.5 4

Saline groundwater from capture 

zone of sumps

4 2.62 1.07–6.14 8 13 0.5 6

PSNS&IMF stormwater 2 1.83 1.50–2.16 2 0 – –

DD1–5 8 1.36 0.63–4.16 8 0 0.3 5.1

DD6 4 1.8 0.97–2.38 6 0 1.3 2.2
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 33

tac11-0637_fig09 Filtered and particulate total mercury, in nanograms per liter

Specific conductance, in microsiemens per centimeter

FTHg = -1.94 + 0.22 * SC

(r = 0.96; p = 0.037)

PTHg = -6 + 0.057 SC

(r = 0.93; p = 0.07)

0 200 400 600 800

200

160

120

80

40

0

Filtered total mercury regression (FTHg)

Particulate total mercury regression (PTHg)

EXPLANATION

Figure 9. Filtered and particulate total mercury relative to specific 

conductance in the effluent from the steam plant, Bremerton naval 

complex, Kitsap County, Washington.

the shoreline and well OUBT-718, which is 40 m upland 

(fig. 4). Similar to the LTMP results, FTHg concentrations 

in saline oxygenated groundwater from OUBT-722 were 

the highest for the two USGS BNC basin-wide sampling 

events, 438 and 541 ng/L. In contrast, groundwater from well 

OUBT-718 was fresh with low concentrations of dissolved 

oxygen (0.5–1.0 mg/L) and an FTHg concentration of 0.8 ng/L 

in April, reflecting groundwater originating from the upland 

basin. Considering the short distance between OUBT-722 to 

OUBT-718, the differences in water types and concentrations 

of FTHg between these two wells indicated that the plume 

of contaminated saline water sampled at well OUBT-722 is 

confined to a thin strip of aquifer along the shoreline.

May 6, 2008 Tidal Study

USGS conducted intensive sampling over selected tidal 

periods at well OUBT-722 to better understand the potential 

for FTHg migration from groundwater to Sinclair Inlet. The 

groundwater from well OUBT-722 was sampled for about 

14 hours on May 6, 2008, as water elevation in Sinclair 

Inlet ebbed from +3.7 m to -1.0 m (MLLW), and flooded 

back to +3.9 m. While water level elevations in the well and 

in Sinclair Inlet were monitored, FTHg and salinity were 

monitored hourly from sampling ports positioned at the top 

of the well OUBT-722 screen (+3.68 m relative to MLLW) or 

just below the water elevation, at mid-depth of 

the screened interval (+1.45 m), and near the 

bottom of the screened interval (-0.6 m). 

The water-level and salinity data clearly 

indicate that marine water saturates the soils 

of the site and then drains back to Sinclair 

Inlet in the vicinity of well OUBT-722 over a 

tidal cycle (fig. 10). Groundwater and Sinclair 

Inlet water levels were nearly identical at 

the 5:00 a.m. high tide. As the tide ebbed 

in Sinclair Inlet, the groundwater level also 

decreased, although at a slower rate. By about 

8:00 a.m., the measurable difference between 

the well elevation and the Sinclair Inlet sea 

surface indicated that seawater was draining 

from the upland area. The rate of decrease 

in the groundwater level slowed when the 

tide was in full ebb, and the groundwater 

level stabilized at approximately +0.96 m 

MLLW before increasing with the flooding 

tide. These measurements indicate there are 

hydraulic characteristics in the vicinity of well 

OUBT-722 that allow for rapid drainage of 

groundwater above about +1 m, but constrain 

groundwater drainage below that elevation. 

The geology log for well OUBT-722 does show 

a contact between contrasting materials at an 

elevation of +1.38 m MLLW, but the material 

change is from fine sandy fill material above 

the contact to fine-coarse sandy fill below the 

contact; the hydraulic characteristics for those two types of 

materials likely are quite similar. Thus, manmade subsurface 

features such as stormwater drains or the seawall more likely 

are the reasons for the constrained groundwater levels below 

+1 m MLLW. The salinity in well OUBT-722 also decreased 

from approximately 24.5 to 20.5 during the later stages of the 

ebb tide, indicating an influx of freshwater. 

FTHg concentrations in groundwater at OUBT-722 over 

the tidal cycle followed a pattern that was neither the same as, 

nor opposite from, changes in groundwater levels or salinity 

(fig. 10). At the three depths sampled within the well casing, 

FTHg concentrations were relatively low during the initial 

high tide (225–312 ng/L), then increased quickly during the 

early stages of the ebbing tide to a maximum of 802 ng/L in 

the sample just below water table, as saline water drained 

from the upland area. Throughout the ebbing tide, the highest 

FTHg concentration was near the top of the water column and 

decreased in samples collected from lower elevations within 

the screened interval. The timing of the increase of FTHg in 

saline water and the vertical distribution of the FTHg indicate 

that the strong source of FTHg was not marine water from 

Sinclair Inlet, but was groundwater drainage from near-ground 

surface soils in the upland area that had been flushed 

with seawater.
34 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

As ebb tide continued and water elevations in both 

Sinclair Inlet and the well dropped, the top sampling port 

was immediately above the mid-point sampling port and 

sampling from the top sampling port was discontinued until 

the following flood tide. As drainage of the upland areas 

continued after 11:00 a.m., maximum FTHg concentrations 

in groundwater decreased to 400 ng/L with the influx of 

freshwater, and dissolved oxygen decreased by 0.2 mg/L (not 

shown). During the following flood tide, groundwater salinity 

increased, but FTHg concentrations continued to decrease 

to below 250 ng/L at all elevations. The timing and vertical 

tac11-0637_fig10

Midnight 4 a.m. 8 a.m. Noon 4 p.m. 8 p.m. Midnight

-1

0

1

2

3

4 0

200

400

600

800

1,000

20

21

22

23

24

25

Time on May 6, 2008

Water elevations, meters,

Mean Low Low Water (MLLW) Salinity

Filtered total mercury, in nanograms per liter

EXPLANATION

FTHg-top sampling port

FTHg-middle sampling port

FTHg-lower sampling port

Salinity

Elevation of Sinclair Inlet 

surface

Elevation of water level in

well OUBT-722

Figure 10. Water levels, total mercury concentrations of filtered water, and salinity in well OUBT-722 during 

the May 6, 2008 tidal study. Salinity was obtained below the sampling port at the bottom of the screened interval, 

Bremerton naval complex, Kitsap County, Washington.

distribution of measured salinity and FTHg concentrations 

indicate that groundwater at well OUBT-722, at a given 

time, is a varying mixture of three end members: (1) saline 

groundwater draining near-ground surface contaminated 

upland soils that has a relatively high FTHg concentration 

(significant during mid-ebb tide), (2) fresh groundwater 

draining from upland areas that has a relatively low FTHg 

concentration (significant during the latter stages of the ebb 

tide, and (3) saline groundwater with a relatively low FTHg 

concentration that directly infiltrates to the well from Sinclair 

Inlet (significant during the flooding tide.)
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 35

One plausible mechanism to explain the May 6 

measurements, is that seawater intruding into the aquifer 

mobilizes aquifer-sediment bound mercury (likely through 

geochemical processes such as complexation with chloride) 

from a unknown location upgradient of well OUBT-722. 

FTHg concentrations greater than 1,000 ng/L were measured 

in saline water collected from wells drilled into clastic soils 

in Southern Tuscany, Italy, containing mercury ores (Grassi 

and Netti, 2000). The geochemical modeling indicates 

that a high degree of complexation with seawater chloride 

mobilizes FHTg from cinnabar deposits that are present in the 

area. The mobilized FTHg passes well OUBT-722 as saline 

groundwater drains towards Sinclair Inlet during the ebb tide. 

This mechanism is consistent with the historical variability 

in mercury concentrations observed in filtered and unfiltered 

water from well OUBT-722 that was not explained by 

differences in turbidity of groundwater samples. 

June 4–5, 2008 Tidal Study

Additional tidal-related data were collected during 

June 4–5, 2008 in the vicinity of well OUBT-722 to gain 

further insight into THg migration in groundwater. Again, 

groundwater in well OUBT-722 was sampled just below the 

fluctuating water table, and water levels in the well and in 

Sinclair Inlet were monitored over an approximate 30-hour 

period that included two ebb cycles (fig. 11). Twenty-five 

FTHg samples were collected with accompanying salinity data 

at about 1 hour increments from near the top of the fluctuating 

water table in well OUBT-722. Water levels in the well were 

measured periodically, and differences between well and 

Sinclair Inlet water levels were measured periodically using a 

manometer board. 

EXPLANATION

FTHg

Salinity

Elevation of Sinclair 

Inlet surface

Elevation of water level 

of well OUBT-722

Midnight 6 a.m. Noon 6 p.m. Midnight 6 a.m. Noon 6 p.m. Midnight

-1

-2

0

1

2

3

4

5 0

500

1,000

1,500

2,000

2,500

24

25

26

27

28

Water elevation, in meters

June 4, 2008 June 5, 2008

Filtered total mercury, in nanograms per liter

Salinity

Figure 11. Concentrations of total 

mercury in filtered water, water levels, 

and salinity in OUBT-722 during the 

during the June 4–5, 2008 tidal study, 

Bremerton naval complex, Kitsap 

County, Washington.
36 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

The range in FTHg concentrations during the June 

sampling was 102 to 2,325 ng/L compared to a range of 148 to 

802 ng/L during the May event. The tidal-induced changes in 

level, salinity, and FTHg concentration of well water measured 

during June 4–5 more clearly illustrate the patterns observed 

on May 6 (fig. 10). FTHg concentrations in groundwater from 

OUBT-722 spiked during the early stages of the large ebbing 

tides when the upland aquifer was draining, and there was 

even a smaller but similar response during the minor ebb in 

the early hours of June 5. Although the morning ebbing cycles 

of May 6 and June 4 were similar (+3.7 to approximately 

-1.2 m), the maximum FTHg concentration measured 

on June 4 (2,090 ng/L) was higher than the maximum 

concentration measured on May 6 (802 ng/L). The maximum 

FTHg concentration of 2,325 ng/L on June 5 occurred after 

a higher high tide of +4.0 m that was at a higher elevation 

than the May 6 higher high tide of 3.7 m. The substantial 

dependence of FTHg concentrations on tidal phase indicates 

that if maximum mercury concentrations are of interest, 

future sampling under the long-term monitoring program at 

OUBT-722 should be conducted during a specified tidal phase, 

preferably at the mid-point during an ebbing tide between a 

high-high and a low-low tide. 

Prior to June 4, 2008, five piezometers were installed 

in the intertidal zone adjacent to well OUBT-722 in order to 

directly measure and estimate, if possible, the loading of FTHg 

in groundwater into Sinclair Inlet. The piezometers were 

installed parallel to the shoreline (fig. 5) to provide additional 

information on the direction of localized groundwater and 

FTHg flow. Groundwater samples were collected from most 

piezometers ten times during June 4–5, 2008, and FTHg was 

measured by WMRL; only six samples were collected from 

piezometer TW-T05 because it was dry during lower tidal 

periods. Median FTHg concentrations in water from the four 

western piezometers (TW-T01 through TW-T04) ranged 

from 0.3 to 1.7 ng/L with individual measurements ranging 

from less than 0.04 to 9.4 ng/L (table 6). In contrast, the 

FTHg concentration found in saline water collected from the 

eastern-most piezometer (TW-T05) nearest the seawall ranged 

between 71.2 and 702 ng/L, with a median concentration of 

194 ng/L. 

The June 4–5 data are consistent with the hypothesized 

mechanism developed to explain the May 6 data; seawater 

intrudes into the aquifer and mobilizes aquifer-sedimentbound FTHg from an unknown location upgradient of well 

OUBT-722, and the mobilized FTHg in saline groundwater 

then drains seaward past well OUBT-722 during the ebb tide. 

The prevalent high concentrations of FTHg at the eastern-most 

piezometer near the seawall strongly suggests that seawater 

contaminated with FTHg largely originates from the direction 

of the PSNS015 stormwater drain, flows along the seawall, 

then flows around the end of the seawall to Sinclair Inlet in the 

vicinity of piezometer TW-T05. 

Mercury in the Stormwater Drain PSNS015

The largest drain in the BNC (PSNS015) located near 

well OUBT-722 (fig. 5) was sampled by USGS during one 

heavy storm event on January 7, 2009, at low tide resulting 

in the collection of non-saline water (specific conductance of 

28 μS/cm). A FTHg concentration of 144 ng/L was measured 

and the sum of FTHg+PTHg (366 ng/L) for this event was 

within the range of WTHg concentrations (15 to 1,131 ng/L) 

for storm events reported by ENVironmental inVESTment 

(2006) for samples collected between 2002 and 2005 

(table C1). 

A key processes leading to the discharge of FTHg to 

Sinclair Inlet may be the tidally-driven pumping of seawater 

into the PSNS015 stormwater drainage system during high 

tides, followed by leakage of seawater into THg-contaminated 

soils of the aquifer; geochemical extraction of soil THg by 

Table 6. Summary total mercury and methylmercury 

concentrations in filtered water, salinity, and particulate total 

mercury from five piezometers installed in the intertidal zone 

seaward of well OUBT-722, Bremerton naval complex, Kitsap 

County, Washington.

[Source of data: Huffman and others, 2012. Concentration of total mercury 

on particles was calculated by dividing the concentration of total mercury 

in nanograms per liter by the concentration of total suspended solids in 

milligrams per liter. The units of nanograms per milligram and milligrams 

per kilogram are the same. Abbreviations: ng/L, nanogram per liter; mg/kg, 

milligram per kilogram; N, number of samples]

Piezometer

TW-T01 TW-T02 TW-T03 TW-T04 TW-T05

Salinity

Median 27.1 26.6 27.4 27.3 27.2

Minimum 25.9 24.9 26.6 27.1 26.8

Maximum 29.0 27.2 28.2 28.7 28.0

Number of samples 10 10 10 10 6

Total mercury, filtered (ng/L) 

Median 1.7 0.3 1.1 1.7 194

Minimum 0.6 0.2 <0.04 0.9 71.2

Maximum 3.1 9.4 2.0 2.3 702

Number of samples 10 10 10 10 6

Methylmercury, filtered (ng/L) (N =1)

0.165 0.09 0.08 0.28 1.5

Calculated concentration of total mercury on particles (mg/kg) (N = 2)

Median 1.98 4.20 2.58 2.21 86.3

Minimum 1.41 1.16 1.85 75.6

Maximum 2.54 3.99 2.56 96.9

Number of samples 2 1 2 2 2
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 37

seawater; and subsequent drainage back into the stormwater 

drain or westward transport to Sinclair Inlet through the 

aquifer behind the 75 m portion of the seawall and past well 

OUBT-722 and TW-05 where the quay is absent. To test 

this hypothesis, USGS sampled PSNS015 from the manhole 

PSNS015-2253 (fig. 5) near the seawall during the ebbing 

cycle from the higher high tide of +3.83 m at 6:10 a.m. of 

March 31, 2010, after only 0.13 cm of rain had fallen in 

the previous 24 hours and there was only a slight chance of 

rain. Because the plug flow of Sinclair Inlet seawater into 

the stormwater drain during the previous flood cycle would 

transport the first water passing by the manhole as it flowed 

out of the stormwater drain, we focused sampling during the 

last 3 hours of the ebbing tide when groundwater most likely 

would drain back into the stormwater drain pipe. 

The sampling port was positioned within the manhole 

vault at the top of the 1.22-m pipe of the stormwater drain. 

Salinity decreased from 14.8 at 9:50 a.m. to approximately 6.1 

at 11:15 a.m. as water level in the manhole vault decreased 

from +1.63 m above the top of the pipe to +0.42 m (fig. 12). 

Salinity remained stable at about 6 for the next 45 minutes as 

the water level dropped to the top of the pipe and below the 

elevation of the sampling port at about noon. The sampling 

port was lowered to the middle of the pipe, where salinity 

was 27.88. Light rain started falling at 11:50 a.m. and stopped 

at 12:10 p.m., but salinity did not decrease appreciably at 

the center of the pipe (noon–12:10 p.m.) during the first 

10 minutes. As the water level continued to drop within the 

stormwater drain over the next 40 minutes, salinity decreased 

to about 21. During the subsequent flooding tide starting at 

1:00 p.m., salinity increased to 28.5. The vertical structure of 

salinity in the manhole vault clearly indicates that the water in 

the stormwater drain was stratified and the stormwater drain 

system is acting as a confined estuary. 

Between 10:16 a.m. (flow of 0.17 m3/s) and 11:52 a.m. 

(flow of 0.15 m3/s), FTHg concentration measured at the top 

of the pipe decreased from 75.4 ng/L to 49.7 ng/L (fig. 13). 

Water initially sampled from the center of the pipe contained 

a FTHg concentration of 39.8 ng/L (salinity of 27.88) and 

decreased to 27.9 ng/L (salinity of 21.85). After the water 

had drained from the manhole vault and was confined to the 

pipe, flow rapidly slowed during the final hour of the ebbing 

tidal cycle. Between 12:40 p.m. and 1:00 p.m. as water levels 

reached their lowest elevations during slack tide and flow 

ceased, FTHg increased to 89.4 ng/L. FTHg decreased to 

undetectable concentrations (10 ng/L) at the center of pipe 

as new Sinclair Inlet water flowed into the pipe during the 

subsequent flooding tidal cycle. Because of changes in flow 

over time, the FTHg concentration of 20.2 ng/L measured 

in the time-averaged composite was much less than the 

flow-weighted concentration of 58.8 ng/L derived from the 

individual hourly concentrations and flow measurements. 

As with the groundwater near OUBT-722, three water 

masses are inferred in the drain PSNS015: (1) saline water 

containing high concentrations of FTHg (observed at the 

beginning of the study); (2) high salinity, low-FTHg water 

from Sinclair Inlet (observed at the end of the study); and 

(3) brackish water containing high concentrations of FTHg 

(after the water drops below the top of the pipe). Unlike the 

groundwater OUBT-722, the brackish water in the stormwater 

drain contained high concentrations of FTHg. The changing 

position of the sampling, changing salinity and changing 

flow during this single 3 hour experiment do not allow for a 

comprehensive understanding of the physical and geochemical 

processes controlling the observed FTHg concentrations. 

However, it is clear that FTHg concentrations of saline water 

in the stormwater drain were higher than concentrations in any 

groundwater sampled outside of the Site 2 area. 

Capture Zone of Sumps

Most of the groundwater in OU NSC and the PSNS&IMF 

is captured by the zone of depression of the drainage systems 

of the six dry docks (Prych, 1997). As with groundwater from 

OU A, well water levels measured in April 2008 were lower 

than those measured in January 2008. Groundwater collected 

from the deepest well (OUNSC-380) in April was the freshest 

groundwater sampled, and thus, was assumed to represent 

the background groundwater FTHg concentration (1.1 ng/L) 

for the BNC. The median FTHg concentration in saline 

groundwater measured by WMRL in April was 2.62 ng/L 

and concentrations ranged between 1.07 ng/L (OUBT-406R 

in April) and 31 ng/L (OUBT-709 in January). Median 

concentrations for the eight samples from Capture Zone of the 

Sumps ranged between 0.5 and 6 ng/L depending on whether 

non-detectable concentrations were set to 0 or 6 ng/L. 

Only one well in the PSNS&INF (OUBT-724, also called 

LTMP-5) was sampled by both USGS and the U.S. Navy as 

part of the LTMP. Well OUBT-724 is located in fill material 

and the surrounding area may be at the edge of the zone of 

depression of the dry docks. WTHg concentrations of 41.6 

and 27.5 ng/L were measured in groundwater from LTMP-5 

by the LTMP in October 2008 and April 2009 using sensitive 

methods, respectively (table A11). These concentrations were 

considerably higher than those measured by USGS in 2008 

(table C1). This difference between USGS data and LTMP 

data may be a result of sampling techniques that resulted in 

lower TSS concentrations by USGS or by natural variations 

caused by varying water elevations. A high concentration of 

WTHg (5,240 ng/L after conversion of units from table A12) 

in groundwater collected from OUBT-724 was measured by 

the LTMP on October 18, 2005 after an extreme high tidal 

stage. Therefore, groundwater containing elevated FTHg may 

be discharging from this fill area. 
38 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig12

0

10

20

30

-1

0

1

2

Salinity at top of drain

Elevation of sonde,

second half of sampling

Lowered

sampling

port

Salinity in middle 

of drain

Water level in vault

Started to rain lightly

Stopped raining

Water level in vault relative to top of drain, in meters

Salinity

Time on March 31, 2010, in Pacific Standard Time

9 a.m. 10 a.m. 11 a.m. Noon 1 p.m. 2 p.m. 3 p.m.

Elevation of sonde,

first half of sampling

Figure 12. Water levels and salinity in stormwater drain PSNS015 during the latter part of the morning ebbing 

tide on March 31, 2010, Kitsap County, Washington.
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 39

tac11-0637_fig13

FTHg less than 10 nanograms per liter

EXPLANATION

Discharge in seaward direction with error bar

Salinity at center of drain

Filtered total mercury

0 0

Time on March 31, 2010, in Pacific Standard Time

9 a.m. 10 a.m. 11 a.m. Noon 1 p.m. 2 p.m. 3 p.m.

Discharge in seaward direction, in cubic meters per second

Salinity

Filtered total mercury, in nanograms per liter

0.6

0.4

0.2

100

80

60

40

20

Water level

at top of pipe

Flux is 0.1 gram in half of 

tidal cycle (3.5 hours)

Figure 13. Flow, filtered total mercury, and salinity in the PSNS015 stormwater drain on the Bremerton naval 

complex during the morning ebbing tidal cycle of March 31, 2010, Kitsap County, Washington. Gray area 

represents the reporting level for filtered total mercury.
40 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

In the PSNS&IMF, FTHg was measured in stormwater 

collected from drains on both sides of a dry dock at low tide 

during a heavy storm event on January 07, 2009, when specific 

conductance of stormwater in stormwater drains PSNS 124.1 

and PSNS124 was 77 and 29 μS/cm, respectively. The median 

FTHg concentration was 1.83 ng/L (table 5) and ranged 

from 1.50 to 2.16 ng/L. USGS results were within the range 

measured by ENVironmental inVESTment (2006) between 

2004 and 2005 (table C1). 

USGS sampled sump water from two dry dock relief 

drainage systems during 2007 and 2008. FTHg was not 

detected in any of the six dry dock samples collected between 

December 2007 and February 2008 that were analyzed 

by the NWQL (reporting level of 10 ng/L), and no FTHg 

concentration from a dry dock sample was greater than 

10 ng/L (table 5). The median FTHg concentration of Dry 

Docks 1-5 discharge water analyzed by the WMRL was 

1.36 ng/L and FTHg concentrations ranged between 0.63 

and 4.16 ng/L. The median FTHg concentration of the mixed 

NWQL and WMRL data set ranged from 0.3 to 5.1 ng/L, 

depending on whether the non-detectable concentrations 

from the NWQL were assumed to be 0 or 6 ng/L. FTHg 

concentrations in Dry Dock 6 discharge water analyzed by 

the WMRL ranged from 0.97 to 2.38 ng/L. The median FTHg 

concentrations of the mixed NWQL and WMRL data set 

ranged from 1.3 to 2.2 ng/L, depending on whether the nondetectable concentration from the NWQL was assumed to be 

0 or 6 ng/L. 

Porewater of Sinclair Inlet Sediment

Four times between August 2008 and August 2009, 

FTHg concentrations in sediment porewater in the top 2 cm of 

sediment from three BNC stations and three greater Sinclair 

Inlet stations were measured as part of the Methylation and 

Bioaccumulation Project (data reported in Huffman and 

others, 2012). FTHg concentrations in porewaters ranged 

between 2.23 and 59.8 ng/L and were not correlated with THg 

concentrations of sediment (STHg). The median porewater 

FTHg concentrations for SI-IN and SI-PO stations were 

25.20 and 17.54 ng/L (table 7), respectively. The lowest 

FTHg porewater concentrations generally were measured 

in February 2009, when cooler temperature and depleted 

nutrients limited biological activity in the water column and 

the sediment. 

Synthesis of Loadings of Filtered Total Mercury 

to Sinclair Inlet

Exchange between Sinclair Inlet and 

Puget Sound

The difference in the transport of FTHg into and out of 

Sinclair Inlet (table 4) provides an estimate of the atmospheric, 

terrestrial and sedimentary sources added to Sinclair Inlet: 

SI SW FW PS SW ( ) [ ]

SI PS

SW FW

C Q Q –C Q 

atmospheric, terrestrial and sedimentary sources,

where

C and C are concentration in Sinclair Inlet and

Puget Sound, respectively, and

Q and Q are consistent with the val

  ×+ × =  

ues of the

flow of saltwater and freshwater

derived in equation 5.

(6)

Transport of Puget Sound seawater into the bottom layer 

of Sinclair Inlet (98 m3/s) containing an FTHg concentration 

of 0.2 ng/L adds 620 grams of FTHg per year of FTHg to 

Sinclair Inlet (table 4). Sinclair Inlet water in the upper 

layer of Sinclair Inlet with a median FTHg concentration of 

0.33 ng/L that is leaving Sinclair Inlet (100 m3/s) transports 

1,040 grams of FTHg per year out of Sinclair Inlet to 

Puget Sound. 

Table 7. Concentrations of filtered total mercury in porewater 

of sediment and fluxes of filtered total mercury from sediment in 

Sinclair Inlet, Kitsap County, Washington between August 2008 

and August 2009. 

[Source of data: Huffman and others, 2010. Field identifier: SI, Sinclair 

Inlet; BNC, Bremerton naval complex; OUT, Outer; IN, Inner; PO, Port 

Orchard. Numbers after BNC stations refer to the grid cell shown in figure 5. 

Abbreviations: cm, centimeter; ng/L, nanogram per liter; ng m-2 day-1, 

nanogram per square meter per day]

Field identifier Number of 

measurements Median Range

Filtered total mercury porewater concentrations (top 2 cm), ng/L

SI-OUT 4 9.30 7.87–10.9

SI-IN 4 25.20 2.95–59.8

SI-PO 4 17.54 4.56–35.9

BNC-39 5 5.18 2.86–16.9

BNC-52 1 6.21

BNC-60 3 4.07 2.72–41.7

BNC-71 4 11.60 2.23–22.7

Flux1

 of filtered total mercury, ng m-2 day-1

SI-OUT 10 38 ND–94

SI-IN 9 269 E14–1,462

SI-PO 9 161 22–492

BNC-39 10 22 (-76)–49

BNC-52 1 0

BNC-60 8 92 73–333

BNC-71 10 46 17–100

Median 46

1The median flux the first measurements of fluxes from cores collected in 

August 2008, February 2009, June 2009 and August 2009. In August 2008, the 

flux from a single core during 2 days after collection was used. For 2009, the 

median of the first measurement from triplicate cores was used. The median 

values for the four sampling periods were used to calculate the range.
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 41

The increase of 0.13 ng/L in the FTHg concentration in 

Sinclair Inlet water above Puget Sound seawater indicates 

that an additional FTHg loading of approximately 420 grams 

of FTHg per year is added to Sinclair Inlet by atmospheric, 

terrestrial, and sedimentary sources (fig. 14). Terrestrial 

sources within the Sinclair Inlet basin include creeks and 

stormwater, municipal effluents, and BNC sources (BNC 

groundwater, stormwater associated with freshwater and 

Zone of direct discharge

Vicinity of site 2

Capture zone of sumps

EXPLANATION

Zones

Puget Sound Naval Shipyard and 

stormwater drain number

IMF Intermediate Maintenance Facility

12.3

PSNS

Atmospheric, terrestrial, and sedimentary 

sources of filtered total mercury, in 

grams per year (*data gap being 

addressed)

To dry

dock Contaminated

groundwater ?

Atmospheric 

wet deposition

34.6

Creeks

27.1*

Dry docks

18.3

Seawater

2.6

Stormwater

drains

12.3

Flux from sediment

hundreds

Wastewater

9.5

Groundwater

0.81

Stormwater

0.03

Steam plant 

effluent

5.9*

Groundwater

1.2

PSNS&IMF

Stormwater

0.48*

Ambient groundwater

2.9

Process water ?

PSNS015

Fresh stormwater

46

PSNS015

Tidal flushing

73

tidal flushing, and industrial effluents). Insofar as the average 

annual transport is based on limited ADCP data record and 

an incomplete knowledge of the factors controlling transport, 

both the transport of Puget Sound seawater to Sinclair Inlet 

and Sinclair Inlet sources may vary by a factor of 2. Since the 

transport of Puget Sound seawater only is known within about 

a factor of 2, the estimated loading from Sinclair Inlet sources 

ranges from about 200 to 800 grams of FTHg per year.

Figure 14. Loadings of filtered total mecury from freshwater sources, from seawater recycled in and out of Bremerton naval 

complex, and from net advective transfers between Sinclair Inlet and Puget Sound, Washington.
42 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Direct Atmospheric Deposition 

THg deposition at Manchester, Washington, located just 

outside of Sinclair Inlet averaged 3.23 μg m-2 yr-1 over the 

18 sampling events with a minimum of 0.51 μg m-2 yr-1 and 

a maximum deposition of 9.38 μg m-2 yr-1 (Brandenberger 

and others, 2010). THg deposition during three 2-week 

sampling events when no rain fell averaged 

0.65± 0.11 μg m-2 yr-1 and provides an estimate of dry 

deposition. Because Brandenberger and others (2010) 

demonstrated a linear relationship between the cumulative 

precipitation per event and the THg flux per event for the 

Manchester site, these data were examined to determine 

how representative precipitation conditions were during the 

18 sampling events. The 18 sampling events represented 

264 days, 44 cm of rainfall, and 2.96 μg m-2 of THg 

deposition. The 44 cm of cumulative rainfall during the events 

is well below the annual averages of 97, 119, and 130 cm 

for 2008, 2009, and the long-term average for Port Orchard, 

respectively. Simply scaling up the measured 2.96 μg m-2 

to annual rainfall yields annual THg depositions of 5.02, 

6.21, and 6.74 μg m-2, respectively. The 6.21 μg m-2 for 

2009 compares well with the THg deposition of 7 μg m-2 

measured at the Seattle National Mercury Deposition Site 

(National Atmospheric Deposition Program, 2010). However, 

this method could overestimate the impact of dry fall THg 

deposition. For an alternative method, the slope of the 

regression of cumulative precipitation per event and the THg 

flux per event for the Manchester data is used:

2 2

2

2

Annual THG wet deposition ( g m ) 0.04 g / m

0.035( g m per cm of rain) annual rainfall (cm)

(R 0.59; value 0.001). p

−

−

μ =μ

+ μ ×

= <

(7)

The intercept value, which represents the dry deposition, 

is not significant and is considerably less than the measured 

value of 0.65 μg m-2 during periods of no rainfall. Using 

equation 7 with the average rainfall of 118 cm for water years 

2002–05 results in a long-term yield of THg wet deposition 

of 4.14 μg m-2 yr-1. The loading of FTHg from atmospheric 

deposition (LATM) is calculated by: 

L Annual THg wet deposition A ATM = × SI. (8)

Using the average rainfall, equation 8 yields a loading of 

34.6 grams of FTHg per year for water years 2002–05.

Loads Discharged to Greater Sinclair Inlet 

For streams and stormwater drain basins, the annual 

loading of FTHg (Li) from was calculated by multiplying 

median FTHg concentrations ( i Cˆ ) by annual water transport to 

Sinclair Inlet (Qi). 

i i Li C *Q ˆ = (9)

If the loadings of FTHg as creek discharge is less than 

the amount of FTHg falling on a watershed as rain, either the 

water was not being delivered to Sinclair Inlet or the THg is 

sequestered in the watershed. The relative importance of the 

delivery of water and the sequestering of FTHg on the loading 

of FTHg from basins was assessed by comparing water yields 

(table 2) and FTHg concentrations in the water source.

Creeks

FTHg concentrations from streams were measured as 

ancillary data as part of a methylmercury survey and not 

specifically for mass loading purposes. Although the rate of 

MHg production is thought to be highest under summertime 

conditions, FTHg concentrations during summer may 

not represent average annual concentrations. In May and 

July 2008, there were no apparent differences between the 

four sampled streams and the median FTHg concentration was 

0.57 ng/L. This FTHg concentration is low compared to THg 

concentrations in rain fall and indicates that most of the THg 

falling on the landscape was retained by the creek watersheds. 

Using an average annual transport of 47.6×106 m3 (calculated 

from the 1.51 m3/s annual average flow; Skahill and LaHatte, 

2007), a loading from creeks was calculated to be 27.1 grams 

of FTHg per year. 

Stormwater

 Using a median FTHg concentration of 4.25 ng/L for 

stormwater drain basins outside of the BNC (table 4) and an 

annual water transport of 2.9×106 m3 (from an average flow 

of 0.093 m3/s; Skahill and LaHatte, 2007), stormwater basins 

are estimated to discharge 12.3 grams of FTHg per year to 

Sinclair Inlet using equation 9. FTHg in three stormwater 

samples collected during winter storm conditions were about 

4 ng/L, indicating little retention of FTHg in stormwater 

during the short time that stormwater flows across the 

landscape to Sinclair Inlet. In contrast, the water yield from 

stormwater basins was only 16 percent of the water yield of 

atmospheric deposition. Thus, most of the water that fell on 

stormwater basins was not transported to Sinclair Inlet as 

surface water, but the THg in the fraction of rainwater that was 

transported to Sinclair Inlet was not removed. 

The estimated atmospheric deposition of FTHg to the 

stream and stormwater basins (86.3 km2) discharging to 

greater Sinclair Inlet is 360 grams of FTHg per year compared 

to the loading of 39.4 grams of FTHg per year to Sinclair 

Inlet from these basins. Some of the remaining 320 grams 

of THg per year flows to Sinclair Inlet in groundwater, but 

the majority of the remaining THg is probably sequestered 

by particles and could eventually be transported to Sinclair 

Inlet as PTHg. It is likely that the calculated FTHg loading 

from stream basins was biased low because of the lack of 

wintertime wet period measurements of FTHg.
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 43

Municipal Effluent

Similar to the stream data, the FTHg concentrations in 

effluent from the City of Bremerton wastewater treatment 

plant were only measured during the dry season and were 

less than 2 ng/L. Since the effluent concentration is less 

than the 5 ng/L measured in atmospheric deposition, 

geochemical processes within the water supply basin and 

engineered processes occurring in water supply and waste 

treatment systems must remove more FTHg than is added 

from anthropogenic sources. Multiplying summertime FTHg 

concentrations by annual total discharge yields an estimated 

loading of 9.5 grams of FTHg per year for the City of 

Bremerton wastewater treatment plant according to equation 9.

Loadings from Bremerton Naval Complex

Although concentrations of FTHg in groundwater in the 

capture zone were measured, most of the groundwater on the 

BNC is confined by a seawall and is captured by the dry dock 

relief drainage systems and no direct groundwater discharge of 

FTHg flux is assumed. Only FTHg loadings from groundwater 

discharge from the zone of direct discharge and from the 

Vicinity of Site 2 are estimated.

Zone of Direct Discharge

Groundwater not constrained by the seawall and 

discharging from most of the shoreline of OU A and western 

OU B Terrestrial (0.006 m3/s in table 2) had a median FTHg 

concentration of 4.06 ng/L. This groundwater contributed 

an annual loading of 0.81 grams of FTHg to Sinclair Inlet 

according to equation 9 with an estimated range between 

0.3 and 1.2 grams of FTHg per year (table 4). The small 

amount of stormwater discharged from this BNC area 

contributes 0.03 g/yr, assuming the two PSNS&IMF 

stormwater samples are representative of this area of the BNC. 

The steam plant is located in western BNC upland of 

the shoreline directly discharging groundwater. In 2008, 

when the plant contained an ion-exchange system, the steam 

plant discharged an average flow of 0.0024 m3/s. FTHg 

concentrations ranged between 15.5 and 143 ng/L (table 4). 

Because of the low discharge rate, the FTHg loading was 

limited to 5.9 grams of FTHg per year according to equation 9 

and likely is now reduced by the conversion to a reverse 

osmosis water-treatment process in 2010.

Vicinity of Site 2

The sources of FTHg from the Vicinity of Site 2 

include groundwater discharge and sources discharged 

through the PSNS015 stormwater drain. FTHg discharged 

from the PSNS015 stormwater drain includes sources from 

tidal flushing of seawater into and out of the aquifer and 

freshwater sources.

Groundwater

The annual loading of FTHg in saline groundwater 

that flows around the westward edge of the seawall and past 

the TW-T05 piezometer was estimated using hydraulic and 

chemical data. Although there are probably density-dependent 

interactions between seawater and freshwater along the 

shoreline in this area, the loading of interest is related to 

only the seawater that moves inland during rising tides 

(either through the subtidal storm drain system or directly 

through beach sediments) and the subsequent draining of 

that seawater—and associated FTHg—back to Sinclair 

Inlet during ebbing tides. Because the seawater essentially 

is a constant density, Darcy’s law was used to estimate the 

groundwater discharge:

gw2b h gw2

gw2b

h

Q K IA ,

where

Q is the transport of groundwater to Sinclair

Inlet from the Vicinity of Site 2 for the

base case, 

K is the saturated hydraulic conductivity of the 

shallow subsurface sediments,

I i

= −

gw2

s the hydraulic gradient between the edge of 

seawall and Sinclair Inlet, and

A is the area of groundwater flow perpendicular

to the shoreline in the Vicinity of Site 2 that 

has elevated FTHg concentrations.

(10)

Reasonable values for the Darcy’s law parameters 

were used to generate the most likely value for Qgw2b, and 

those values were adjusted to generate plausible minimum 

and maximum values of flow. For the base case, Kh was 

assumed to be constant throughout the vicinity of OUBT722 with a value of 0.0134 cm/s (38 ft/d), the “expected” 

value for sediments in the area (Site 10W in table 5-2, U.S. 

Navy, 2002). The area A of groundwater flow (Agw2) that has 

elevated FTHg concentrations represented by those measured 

in TW-T05 was assumed to be 21 m2 (7 m wide and 3 m 

thick; fig. 5). Estimating a reasonable value for the hydraulic 

gradient I was more involved. 

Assuming that there is substantial saline groundwater 

discharge to the Inlet during only about half of each day, an 

average daily value for I was estimated. During June 4–5, 

2008, the periods of significant discharge started during the 

ebb that followed the 5:00 a.m. high tide and ended about 

10 hours later, midway into the flood that followed the 

subsequent low tide (fig. 11). It is likely that there also were 

a few hours of less substantial discharge to the Sinclair Inlet 

during the smaller ebb and flood cycle to and from lower‐high 

tide around midnight. The preliminary average value of 

0.14 meter/meter (m/m) for I was estimated by averaging the 

hourly seaward gradients, which were calculated by dividing 

the differences in water levels in well OUBT-722 and the 

marine water surface (0.1–3 m) by the distances between the 
44 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

well and the marine water surface (1–16 m). This preliminary 

value was then reduced by half (down to 0.07 m/m) to 

account for 12 hours of each day when there is no appreciable 

groundwater discharge to the Sinclair Inlet. 

The resulting estimated groundwater flux Qgw2b was 

approximately 0.0002 m3/s (17,000 L/d). The annual loading 

of FTHg in saline groundwater that flows around the westward 

edge of the seawall and past the TW-T05 site was estimated by 

multiplying the annual groundwater flow (6.2×103 m3/yr) 

by the median FTHg concentration, measured in TW-T05 

(194 ng/L) according to equation 9, to get a loading of 

1.2 grams of FTHg per year. A plausible minimum value for 

the FTHg loading of 0.6 g/yr could be calculated by assuming 

the Kh value was less by a factor of two. A plausible maximum 

value for the FTHg loading of 2.5 grams of FTHg per year 

could be calculated by assuming the Kh value was equal to the 

highest value reported for fill material at the site (tables 3–13, 

U.S. Navy, 2002).

Discharge through PSNS015 Stormwater Drain

In contrast to other BNC sources, scaling up single 

measurements of freshwater, and saline and water releases to 

annual releases indicates that discharge from the PSNS015 

stormwater drain system accounts for the largest release of 

FTHg from the BNC, and possibly the largest load of FTHg to 

Sinclair Inlet. At a manhole (PSNS015 A42) slightly upland 

from Site 2 (fig. 5), a single sample of low-conductivity 

stormwater collected by USGS from the PSNS015 system 

contained a FTHg concentration of 144 ng/L, which was 

consistent with the measurements of the ENVVEST project. 

Applying an average annual flow of 0.010 m3/s and one FTHg 

concentration, yields a highly uncertain FTHg loading of 

46 grams of FTHg per year from fresh stormwater discharged 

through the PSNS015 stormwater system (table 4). The 

possible sources of this freshwater FTHg could include 

(1) side drains discharging into the vault that service parts 

of Site 2, (2) unknown THg sources upgradient of Site 2, or 

(3) residual effects of tidal flushing of the storm drain through 

Site 2, as discussed in the following paragraphs. 

It is likely that high concentrations of FTHg in fresh 

and saline water in the PSNS015 stormwater drain system 

originate from interactions with contaminated subsurface soils 

at the site rather than from above ground sources. The data 

collected as of 2010 indicate that geochemical processes are 

releasing THg into both saline and fresh waters entering the 

PSNS015 stormwater drain system. 

The size, complexity, and construction of the PSNS015 

stormwater drain system, in which a 1.3-m pipe passes 

through the seawall at an elevation lower than MLLW, 

facilitates the extraction of soil THg by tidal flushing of 

seawater. Seawater leaking from the complex system of 

vertical vaults and horizontal drains near ground level during 

high tides, flows through the contaminated soil (fig. 15A) and 

extracts THg because of its chemical affinity with the chloride 

ion in seawater. Some of this high FTHg saline groundwater 

then flows east along the seawall resulting in groundwater 

FTHg concentrations as high as 2,090 ng/L in upland well 

OUBT-722 (fig. 11) and as high as 702 ng/L in an intertidal 

piezometer TW-T05 (table 6). Some of the contaminated 

seawater flows back into the stormwater drain system and 

is discharged to Sinclair Inlet through the stormwater pipe 

independent of storm events (fig. 15B). 

What essentially is a subterranean estuary is maintained 

in the 1.3-m storm drain pipe where brackish water sits on 

top of the more dense seawater flowing in from Sinclair Inlet 

(fig. 16). The brackish water is a mix of stormwater and 

contaminated groundwater that seeps back into the presumably 

leaky pipe. Immediately seaward of where the pipe passes 

through the seawall, there is 90 degree downward bend in the 

pipe that connects to a vertical riser. This vertical pipe then 

connects to a horizontal pipe that extends some distance from 

the shoreline. This pipe configuration likely contributes to the 

stability of the subterranean estuary. During the March 31, 

2010, tidal sampling when the low tidal elevation in Sinclair 

Inlet was -0.31 m, the water level in the stormwater drain 

pipe was only 0.3 m below the top of the pipe. During the 

flooding tide, marine water from Sinclair Inlet with lower 

FTHg concentrations entered the bottom of the stormwater 

drain through the vertical riser and pushed the contaminated 

water both up the vault and back up the stormwater drain 

pipe (fig. 16A). During the normal ebbing tides on March 31, 

2010, some FTHg in the brackish water leaked from this 

subterranean estuary to Sinclair Inlet through dispersion in the 

pipe, but most FTHg likely was retained in the pipe (fig. 16B). 

On March 31, 2010, during 3.5 hours of one ebbing tide 

period when little rain fell, 1,770 m3 of saline water with 

a flow-weighted average FTHg concentration of 58 ng/L 

discharged through the seawall in the PSNS015 storm drain 

to Sinclair Inlet. The calculated loading of FTHg during this 

partial ebbing tide contributed a loading (LE) of 0.1 grams of 

FTHg to Sinclair Inlet. Scaling this loading to a year yields a 

highly uncertain estimated loading of approximately 73 grams 

of FTHg per year from tidal flushing to Sinclair Inlet through 

the stormwater drain according to:

TF E E

TF E

L N L,

where

L is the loading from tidal flushing and N is the

number of ebb tidal cycles in a year (730).

= × (11)

The elevation of the bottom of the pipe at the seawall 

and the angle of the pipe just seaward of the stormwater 

drain could lead to episodic releases of FTHg. During the 

ebbing tides when fresh stormwater runoff fills the vaults, the 

hydraulic head of fresh stormwater might be sufficient to push 

the contaminated seawater out of the storm drains (fig. 16C). 
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 45

tac11-0637_fig15a

Well OUBT-722

Temporary well T-05

Wycoff Way

Sea wall

Main storm drain

West Road storm drain

4-foot diameter

storm drain

outflow

Manhole

Contaminated

groundwater

Fresh

groundwater

High FTHg saline groundwater

Contaminated groundwater

Fresh groundwater

Ground

Contaminated soils

Sea wall

EXPLANATION

Low FTHg saline water

Rock

A.

Figure 15. Extraction of Site 2 soils by seawater leaking from and flowing to PSNS015 stormwater drain system on the Bremerton 

naval complex, Kitsap County, Washington. (A) Seawater leaking into soils from the main storm drain and near-surface side drains at 

high tide and extracting THg from soils. (B) Contaminated saline groundwater flowing back into the storm drains and along the seawall 

to OUBT-722 and piezometerTW-05 from the main storm drain and near-surface side drains at high tide and extracting THg. 
46 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig15b

Well OUBT-722

Temporary well T-05

Wycoff Way

Sea wall

Main storm drain

West Road storm drain

4-foot diameter

storm drain

outflow

Manhole

Contaminated

groundwater

Fresh

groundwater

High FTHg saline groundwater

Contaminated groundwater

Fresh groundwater

Ground

Contaminated soils

Sea wall

EXPLANATION

Low FTHg saline water

Rock

B.

Figure 15.—Continued
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 47

tac11-0637_fig16

Manhole

2253

Seawall

Manhole

A42

HAZMAT

Building

A. Normal high tide B. Normal low tide

At high tide, clean water comes 

in from the bottom of the drain 

and moves upward.

During normal low tides, slightly 

contaminated seawater leaks to 

Sinclair Inlet.

Contaminated 

groundwater 

upgradient

Mercury- (Hg) contaminated brackish water

Clean seawater

EXPLANATION

Sinclair Inlet

surface 

Manhole

2253

Seawall

Manhole

A42

HAZMAT

Building

Highly Hg-contaminated seawater

Moderately Hg-contaminated seawater

Fresh surface runoff Slightly Hg-contaminated seawater

Sinclair Inlet

surface 

Manhole

2253

Seawall

Manhole

A42

HAZMAT

Building

C. Low tide with rainfall D. Extreme low tide

Head from accumulating surface 

runoff will push moderately 

contaminated seawater out pipe.

Construction of PSNS015 could 

lead to episodic releases of 

contaminated water at extreme 

tides.

Sinclair Inlet

surface 

Manhole

2253

Seawall

Manhole

A42

HAZMAT

Building

Sinclair Inlet

surface 

Figure 16. Episodic releases of filtered total mercury during certain tidal conditions. (A) Normal high tide, (B) normal low tide, (C) 

episodic release during low tide with rainfall, and (D) episodic release during extreme low tide. 
48 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

During extreme low tides of -1 m MWWL (often seen within 

a month of the summer solstice), the episodic emptying of the 

PSNS015 stormwater drain pipe in the absence of storm events 

could cause a large loading of FTHg to Sinclair Inlet (fig. 16D). 

The highest FTHg concentration measured in marine waters of 

Sinclair Inlet by USGS (11.4 ng/L) was in a sample collected on 

June 2, 2009 at station BNC-39 near the end of the submerged 

PSNS015 pipe. WTHg concentrations as high as 10.71 ng/L 

were measured in upper layer waters from OU B Marine 

(table C1) at a station off Site 2. 

The residual effect of tidal flushing is hypothesized to 

involve a complex sequence of physical and geochemical 

processes that separates the FTHg from the salt. First, FTHg 

in the contaminated seawater is pushed up drain during 

the flooding tide. Next, FTHg absorbs onto surfaces, such 

as the storm drain pipe, vaults and soils upgradient of the 

contaminated site. During the ebbing tide, the seawater is 

drained from the system, leaving some FTHg behind. Finally, 

FTHg is released to lower-FTHg, fresher stormwater that comes 

in contact with these surfaces. 

Capture Zone of Sumps 

The stormwater collected from the PSNS&IMF had 

median FTHg concentrations of 1.83 ng/L. The calculated 

loading was 0.48 grams of FTHg per year using equation 9 and 

the flow from table 2, indicating that discharge of FTHg from 

PSNS&IMF is not a significant source of FTHg to Sinclair Inlet.

Using FTHg concentrations measured by the WMRL, the 

median FTHg concentration of discharges collected from sump 

wells of Dry Docks 1-5 results in a loading of 6.9 grams of 

FTHg per year according to equation 9. The loading varies 

between 3.2 and 26 grams of FTHg per year depending on 

whether the non-detectable concentration from the NWQL 

was assumed to be 0 or 6 ng/L (table 4). The median FTHg 

concentration collected from the sump well of Dry Dock 6 

was 1.81 ng/L, which results in an estimated annual loading 

of 11.4 grams of FTHg according to equation 9 (table 4). 

Estimates of FTHg loading from Dry Dock 6 ranged between 

8.2 and 13.9 g/yr, depending whether non-detectable 

concentrations measured by the NWQL were assumed to be 

0 or 6 ng/L. 

The 18.3 grams of FTHg per year discharged from 

the dry docks (table 4) originated from FTHg in (1) the 

seawater seeping into the dry docks, (2) FTHg in ambient 

groundwater captured by the dry dock sumps, (3) the release 

of THg from contaminated BNC soils into fresh or saline 

water that is captured by the sumps, and (4) FTHg inputs 

from naval operations (table 8). The calculated contribution 

from ambient groundwater drawn in the sumps was 2.9 grams 

of FTHg per year based on a concentration of 1.1 ng/L 

for fresh, deep ambient groundwater collected from well 

OUNSC 380 (table 5). Using the mean FTHg concentration 

of 0.31 ng/L for Sinclair Inlet seawater collected in the lower 

layer OU B Marine (table 3), the calculated contribution from 

seeping seawater is 2.6 grams of FTHg per year (range: 1.8 

to 6.0 grams of FTHg per year). The remaining 13 grams of 

FTHg per year was contributed as FTHg in process water 

added by naval operations and from leaching of BNC soils by 

saline or fresh groundwater that is captured by the dry docks. 

Table 8. Possible sources of filtered total mercury discharged by the dry dock relief drainage systems, Bremerton naval complex, 

Kitsap County, Washington.

[Abbreviations: m3/s, cubic meter per second; ng/L, nanogram per liter; g/yr, gram per year; NA, not applicable; OU B, Operable Unit B]

Water

(m3

/s) Freshwater

Number 

of 

samples

Concentration

(ng/L)

Loading

(g/yr)

Median Range Median Range

Ambient groundwater NA 0.083 1 1.1 NA 2.9 NA

Seeping seawater from OU B Marine 0.27 NA 13 0.25 (1

0.31) 0.21–0.72 2.6 1.8–6.0

Process water 0.010 0.010 NA NA NA NA NA

Possible sources from contaminated saline 

groundwater

0.27 NA 8 2.62 1.07–31 2.0 7–260

Total for dry docks 0.36 0.093 NA NA NA 18.3 NA 

1

Mean for a large data set of 21 samples.
Sources and Sinks of Filtered Total Mercury to Sinclair Inlet 49

Only 1 of 13 groundwater samples (13 percent) collected 

by USGS in the capture zone of the dry docks contained 

a FTHg concentration greater than 10 ng/L (table 5). A 

concentration of 31 ng/L was measured at well OUBT-709 

(fig. 4), in an area filled with naval waste materials (Site 10C 

in U.S. Navy, 1992). Additionally, one sample measured by 

the LTMP in 2005 from LTMP-4 (fig. 3) in another area of 

fill material (Site 10E in US. Navy, 1992) contained a WTHg 

concentration of 5,240 ng/L. There clearly is a large range of 

measured FTHg concentrations in groundwater thought to be 

captured by the dry dock relief drainage systems (table 8). 

Equally large is the range of median FTHg concentrations in 

dry dock discharges. Consequently, no definitive conclusion 

can be made on the relative importance of naval operations 

and contaminated groundwater contributing to the FTHg 

loading from the dry docks. 

Marine Sedimentary Sources

Although the FTHg in marine sediment porewater drives 

the flux of FTHg out of the sediment, the flux of FTHg out 

of Sinclair Inlet sediment was assessed independently of 

the porewater concentrations by conducting core incubation 

experiments as part of the Methylation and Bioaccumulation 

Project (Huffman and others, 2012) using sediment collected 

from three stations in greater Sinclair Inlet and three stations 

in OU B Marine (fig. 4). The highest station median fluxes of 

FTHg of 269 and 161 ng m-2 day-1 (table 7) were calculated 

from increases in FTHg in water over stirred incubated 

cores collected from Sinclair Inlet stations SI-IN and 

SI-PO, respectively. The large range of values at each site 

demonstrates the seasonal variability of the FTHg flux from 

the sediment. Similar to FTHg porewater concentrations, 

the largest FTHg fluxes were calculated from incubation 

studies of cores collected in June or August 2009 and the 

smallest FTHg fluxes were calculated from cores collected 

during February 2009. The flux of FTHg from sediment is 

highly dependent on the season of the year and appears to be 

controlled by the deposition of organic matter to sediments 

from biological productivity in the upper layer. The median 

flux of the seven stations was 46 ng m-2 day-1. 

It is imprudent to attempt to quantitatively scale the 

results from these seven stations to a Sinclair Inlet-wide 

flux from sediment without fully understanding the factors 

that control the flux both geographically and temporally. 

To provide an order of magnitude assessment of the release 

THg from sediment, the minimum (BNC-39) and maximum 

(SI-IN) median fluxes for stations with at least three flux 

measurements were applied to the sediment surface area of 

Sinclair Inlet according to:

S SI

S

SI

L Flux A ,

where

L is the sedimentary loading,

Flux is the sedimentary flux of FTHg, and

A is the area.

= × (12)

This order of magnitude analysis indicates that between 

67 and 820 grams of FTHg are added to Sinclair Inlet 

each year. This estimate can only be refined with a better 

understanding of the seasonal variation over the entire Sinclair 

Inlet. Thus, the flux of FTHg from Sinclair Inlet sediment is 

large and potentially in the hundreds of grams.

Ranking of Sources of Filtered Total Mercury to 

Sinclair Inlet

Most of the 0.33 ng/L of FTHg in the water column of 

Sinclair Inlet originates from Puget Sound. The sources of 

FTHg added directly to Sinclair Inlet were divided into four 

broad categories based on their mass loading: category (IV), 

sources greater than 100 grams of FTHg to Sinclair Inlet; 

category (III), sources ranging between 10 and 100 grams of 

FTHg to Sinclair Inlet; category (II), sources ranging between 

1 and 10 grams of FTHg to Sinclair Inlet; and category (I), 

sources discharging less than 1 gram of FTHg per year. 

Category IV sources include diffusion from the Sinclair Inlet 

sediment and the combined freshwater discharge and tidal 

flushing from the largest stormwater drain system (PSNS015) 

on the Bremerton naval complex. However, the numerical 

values of the loading of these two sources are highly 

uncertain. The four Category III sources include atmospheric 

deposition, and discharge from creek basins, greater Sinclair 

Inlet stormwater basins and the industrial BNC dry dock 

systems. If FTHg concentrations in streams are higher during 

winter conditions than summer conditions, these calculations 

will cause an underestimate of the annual loadings of FTHg. 

The loading of FTHg in groundwater discharging to greater 

Sinclair Inlet has not been assessed. It is uncertain if the FTHg 

being discharged by the dry docks originates from naval 

operations or extraction of THg from BNC soils as the dry 

dock sumps draw in ambient fresh groundwater and saline 

water from Sinclair Inlet. The release of FTHg by groundwater 

from two fill areas that may be captured by the sumps needs 

further study. Category II sources include municipal effluent 

discharging into Sinclair Inlet, industrial discharges from the 

BNC steam plant, and groundwater water discharge around 

the end of the seawall in the Vicinity of Site 2. The conversion 

of the steam plant to a reverse osmosis system in 2010 likely 

decreased this FTHg source. Stormwater discharges from the 

Zone of Direct Discharge and Capture Zone of the Sumps do 

not appear to be a significant source of FTHg (category I). 
50 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Concentrations of Total Mercury of 

Solids Discharged to Sinclair Inlet

In the absence of a balance between the mass of solids 

entering the water column of Sinclair Inlet and the mass of 

solids leaving the water column through sedimentation or 

advection out of Sinclair Inlet (table 2), a qualitative analysis 

of the source of solid-phase THg is presented here. This 

qualitative analysis focuses on comparing THg concentrations 

of suspended solids among source waters (tables C2–C3) and 

with solids suspended in the water column of greater Sinclair 

Inlet and OU B Marine (table C4). Although this analysis is 

not a comprehensive mass balance on solid-phase THg, it 

does provide insight into critical issues for the Sinclair Inlet 

concerning how quickly (if at all) natural recovery is currently 

proceeding, and whether there is a need for additional 

remediation of mercury sources. 

Solids Discharged to Greater Sinclair Inlet

 Solids containing THg are discharged to greater Sinclair 

from creek and stormwater basins and from wastewater 

treatment plants. This PTHg originates from dry fall on the 

landscape of Sinclair Inlet watershed, the sequestering of 

FTHg in rainwater by soil particles, leaching of THg from 

natural soils, and use of mercury by industry, commerce, 

and households within the basin. Although the average THg 

dry deposition of 0.65±0.11 μg m-2 yr-1 was measured in 

dry fall by Brandenberger and others (2010), corresponding 

THg concentrations on the deposited particles are not known 

because TSS concentrations in the samples washed off the 

sampler were not measured.

Creek

THg concentrations of suspended solids in four creeks 

in May and July 2008 were generally less than 0.25 mg/kg 

(fig. 17), except for the two samples from Annapolis Creek 

that averaged 0.27 mg/kg (table C2). The maximum THg 

concentrations of solids inferred from the slope of WTHg 

versus TSS concentrations (table A7) measured by ENVVEST 

(0.064 to 0.17 mg/kg) were similar to THg concentrations of 

solids measured by USGS (0.064 to 0.23 mg/kg). The THg 

concentrations of solids from Olney Creek (0.14 mg/kg), just 

outside of the model domain, were within the range of THg of 

solids for the four Sinclair Inlet creeks. 

Stormwater Basins

Concentrations of THg of solids measured on stormwater 

particles discharged into Sinclair Inlet (table C2) were 0.096 

and 0.138 mg/kg and were slightly less than the measured 

THg concentration of solids (0.157 mg/kg) from a City of 

Bremerton storm drain discharging outside of Sinclair Inlet 

(Sheridan Road site in fig. 1). The maximum concentration of 

solids inferred from the slope of WTHg versus TSS measured 

by ENVVEST for samples collected at location LMK122 

(0.38 mg/kg) was greater than the THg concentration of solids 

(0.096 mg/kg) collected by USGS at the same location (Navy 

City near Gorst in table C2). The USGS sample may have 

been affected by road dirt from a nearby highway construction 

site flowing into the drainage ditch during storm sampling. 

Wastewater Effluents

THg concentrations of wastewater solids filtered 

from the City of Bremerton wastewater treatment plant 

(WWTP) effluent were measured from three 5-L composite 

samples prepared in May, July, and August 2009. THg of 

wastewater solids ranged from 0.183 to 0.210 mg/kg (table C2

and fig. 17).

Solids Discharged from the Bremerton 

Naval Complex

Sources of PTHg discharged from the BNC include 

industrial sources and stormwater discharge. USGS sampled 

water discharged from four industrial outfalls from three 

regulated sources that included sump water from two dry 

dock relief drainage systems and the industrial effluent from a 

steam plant during 2007 and 2008. As with FTHg, the release 

of PTHg from tidal flushing of the PSNS015 stormwater 

drain system also was examined. Although transport of PTHg 

by groundwater discharge to Sinclair Inlet is not included in 

the mass balance, solids in ambient and BNC groundwater 

are captured by the dry docks sumps; and sump water is 

discharged to Sinclair Inlet.

Zone of Direct Discharge

TSS concentrations (0.75–1.45 ng/L) and TSS 

loading (0.09 metric tons) in steam plant effluent were 

low. Concentrations of THg of solids varied from 2.95 to 

68.74 mg/kg (fig. 18, table C3). Similar to FTHg in steam 

plant effluent, THg of solids increased with increasing specific 

conductance (fig. 9). Similar to FTHg, THg concentrations 

of steam plant solids likely decreased with conversion to a 

reverse osmosis treatment system in 2010.

Vicinity of Site 2

A TSS concentration of 222 ng/L was measured in nonsaline stormwater collected from stormwater drain PSNS015 

within Site 2 during the January 9, 2009, storm event. The 

THg concentration of solids in this non-saline water was 

1.49 mg/kg (fig. 18). 
Concentrations of Total Mercury of Solids Discharged to Sinclair Inlet 51

tac11-0637_fig17

0

Gorst

Anderson

Blackjack

Annapolis

Greater

Sinclair

Inlet

Suspended

Solids

Bremerton

WWTP

Navy City

LMK122

Port

Orchard

Marina

Streams Stormwater

Total mercury concentrations of solids, in milligrams per kilogram

0.6

0.4

0.2

Direct measurement by USGS

Maximum

Median

Maximum concentration calculated from 

ENVVEST data

EXPLANATION

Figure 17. Concentrations of total mercury of 

suspended solids in streams, stormwater, and 

wastewater treatment plants in the Sinclair Inlet 

basin, Kitsap County, Washington measured 

by USGS (2008–09), maximum concentrations 

calculated from ENVVEST data (2002–05), and 

concentrations in solids suspended in the upper 

layer of greater Sinclair Inlet.

0

10

20

30

40

50

4 4

Solids loading 

= 0.09 metric ton per year

UNK UNK

DD1–5 DD6 Steam

plant

PSNS&IMF

Stormwater

PSNS015

Storm

event

PSNS015

Tidal

flushing

OU B

Suspended

solids

OU B Marine sedimentation 

= 1,610 metric tons per year

Total mercury concentrations of particles, in milligrams per kilogram

Sources of solids

Less than 2.6

90 Percentile

75 Percentile

Median

25 Percentile

10 Percentile

EXPLANATION

Figure 18. Concentrations of total mercury 

of solids originating from Bremerton naval 

complex, Kitsap County, Washington. (The 

whisker box plots do not include samples 

with total suspended solid concentrations 

less than 0.5 mg/L that likely are biased by 

sequential sampling during changing TSS 

conditions. The labels above the whisker 

boxes indicated the estimated loading 

of total suspended solids in metric tons 

per year. UNK indicates solids loading is 

unknown.)
52 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

The THg concentrations of suspended solids for the two 

sampling events of the ebbing tidal cycles on December 29, 

2010, and March 31, 2011, were 16.2 and 19.1 mg/kg, 

respectively (fig. 16 and table C3). The THg concentrations 

of these solids were considerably larger than the THg 

concentrations of solids in the PSNS015 stormwater drain 

associated with the storm event (1.49 mg/kg), but within 

the range of THg concentrations found for soils in Site 2 

(table A1). Thus, the small amount of solids flowing from 

PSNS015 stormwater drain during ebbing tides are distinctly 

different than storm drain particles from surface runoff and 

the solids discharged during non-storm ebbing tides appear 

to be soil particles leaking into the PSNS015 stormwater 

drain system. 

Capture Zone of the Sumps

The loading of solids from BNC stormwater 

drains is unknown. Two stormwater samples collected 

from PSNS&IMF during storm events contained high 

concentrations of TSS (table C3). The concentrations of THg 

of the stormwater solids were 0.21 and 0.495 mg/kg (fig. 18). 

TSS concentrations in dry dock discharges ranged 

from 0.16 to 1.47 mg/L, except when maintenance of 

the sump wells was occurring (June 24, 2008). When 

TSS concentrations were greater than 0.5 mg/L, THg 

concentrations of solids were less than 6 mg/kg, with median 

concentrations of 3.23 mg/kg and 2.42 mg/kg for solids from 

Dry Docks 1–5 and 6, respectively (table C3). The highest 

THg concentrations of solids collected from the Dry Docks 

1–5 system (13.2 mg/kg in December 2007) and from the Dry 

Dock 6 system (17.7 mg/kg in April 2008) were associated 

with the lowest TSS concentrations for each dry dock system 

(0.49 mg/L and 0.16 mg/L, respectively). 

Concentrations of metals increase with decreasing 

particle size because of increasing surface-to-volume ratios. 

Physical settling of the coarser fraction of the original particles 

entering the dry dock drainage system is a likely mechanism 

causing the observed relation between mercury concentrations 

of solids versus TSS concentrations. Particle-size effects 

may have been exacerbated by the sequential sampling for 

PTHg and TSS during the pumping cycle. When the pumps 

turn on, solids near the pump inlet likely are resuspended by 

turbulence, resulting in higher TSS and PTHg concentrations 

at the beginning of the pumping cycle when the PTHg samples 

were collected. As the pumping cycle continues, the water that 

is being pumped comes from the increasing distances from the 

pump, which likely had lower TSS concentrations. Since the 

TSS sample was always collected last, the TSS sample likely 

underestimates the TSS concentration of water at the time 

particulate THg samples were collected at the beginning of 

the cycle. 

For the December 2007 sampling of Dry Dock 1-5 from 

the discharge pipe of Pump 4, the dramatic difference between 

the THg concentration of solids calculated from sequential 

sampling with two different bottles and the THg concentration 

of solids calculated from PTHg and TSS samples collected 

from a single bottle containing the 24-hour composite sample 

support the hypothesis of bias from sequential sampling during 

changing TSS conditions. The THg concentration for the 

sequential sampling of two grab samples at the Dry Dock 1–5 

system was 13.2 mg/kg. In contrast, the THg concentration of 

solids obtained from PTHg and TSS measurements aliquots 

from the same composite bottle filled the previous 24 hours 

was near the median concentration (3.75 mg/kg).

Synthesis of Concentrations of Total Mercury of 

Solids Discharged to Sinclair Inlet 

Solids discharged into greater Sinclair Inlet and OU B 

Marine enter the water column after undergoing geochemical 

processes occurring in brackish water and physical 

settling of coarser particles in the small mixing zone of the 

discharge. Thus, source solids contribute to the population 

of solids suspended in the upper layer of Sinclair Inlet, but 

the exact contribution of the sampled solids is unknown 

because of the lack of a mass balance of solids for Sinclair 

Inlet. THg concentrations of solids (fig. 17) from streams 

(0.64–0.283 mg/kg), stormwater (0.96–0.157 mg/kg), and 

even wastewater effluent (0.183–0.210 mg/kg) discharging 

into greater Sinclair Inlet generally were within the range 

of concentrations of THg of solids suspended in the upper 

water column of greater Sinclair Inlet (0.23+0.17 in table 3). 

Likewise, THg concentrations of solids (fig. 18) from the 

PSNS&IMF stormwater drains (0.21–0.495 mg/kg) were 

within the range of THg concentrations of solids suspended in 

the upper layer of OU B Marine (0.23+0.13 in table 3).

In contrast, THg concentrations of solids from the steam 

plant (2.95–40.9 mg/kg) and from stormwater drain PSNS015 

during tidal flushing (16.2–19.1 mg/kg) were significantly 

higher than THg concentrations of solids suspended in the 

upper water column of OU B Marine (fig. 18). The THg 

concentrations of particles discharged from the dry dock 

drainage relief systems (1.32–5.17 mg/kg) and from the 
Concentrations of Total Mercury of Solids Discharged to Sinclair Inlet 53

PSNS015 stormwater drain during a storm event (1.46 mg/kg) 

were slightly higher than THg concentrations in OU B Marine. 

Statistical comparisons were not performed on the source 

solids because it is not known how the collected particles are 

representative of the population of solids in either the water 

column or the sediment in the absence of a mass balance 

of solids. 

Direct settling of suspended solids within the water 

column of this U-shaped basin (fig. 6) has been measured 

(U.S. Navy, 2007b cited in Paulson and others, 2010). This 

mechanistically direct transport of solids between the water 

column and the sediment column is examined by comparing 

THg concentrations of suspended in the water column of 

Sinclair Inlet with STHg concentrations of bulk Sinclair Inlet 

sediment. The quality of the STHg measurements of whole 

sediment samples by the LTMP was assessed in Paulson and 

others (2010) and found to be acceptable. The percentages 

of fines of the whole LTMP sediment are shown in figures 2

and 3. Additionally, the large number of measurements of 

THg of suspended solids from the marine water column in 

Sinclair Inlet (table 3) by USGS as part of the Methylation and 

Bioaccumulation Project in 2008 and 2009 allows statistical 

comparison with STHg concentrations reported by the U.S. 

Navy between 2003 and 2007, and in 2010 as part of the 

LTMP. In this study, the cumulative probability distributions 

of THg concentrations on suspended solids and of STHg 

concentrations of sediment samples are compared separately 

for OU B-Marine and greater Sinclair Inlet. Cumulative 

probability distributions provide not only information on the 

median (a cumulative probability of 0.5), but also provide a 

visual depiction of distribution of concentrations. 

The cumulative probability distribution of THg 

concentrations of solids suspended in the upper layer of 

greater Sinclair Inlet (fig. 19) is statistically (p <0.001) lower 

than (to the left of) the distribution of STHg concentrations 

measured before this study (2003–07). This observation 

indicates that sedimentation of these lower concentration 

THg-solids in the water column should cause a decrease 

in STHg concentrations in surface layer of Sinclair Inlet 

sediment over time. This decrease would occur even if 

preferential settling of coarser, larger-sized solids were 

occurring in the water column. The coarser, larger-sized solids 

likely would have a lower THg concentration because of the 

lower surface area-to-volume ratio of these larger-sized solids 

compared to the smaller-sized solids that might be advected to 

Puget Sound. THg concentrations of solids suspended in the 

lower layer of the water column were not statistical different 

from THg in the upper water column (both category B for 

the post-Anova Tukey multicomparison test in last column 

of table 3). The cumulative probability distribution of STHg 

in Sinclair Inlet sediment collected after the study in 2010 

(U.S. Navy, 2011) was to the left (lower concentrations) 

of that of sediment collected in 2003, 2005, and 2007, but 

not statistically lower (p value=0.18). A rate of decrease of 

STHg concentrations in sediment of Sinclair Inlet cannot be 

accurately modeled until the sources of the solids suspended in 

Sinclair Inlet are quantified.

Similar to greater Sinclair Inlet, THg concentrations of 

solids suspended in the upper layer of OU B Marine collected 

(table 3) in 2008 and 2009 were significantly lower (p <0.001) 

than STHg concentrations of sediment from OU B Marine 

collected before the study (fig. 20). Unlike greater Sinclair 

Inlet, THg of solids in the bottom layer of OU B Marine 

(multicomparison category A in table 3) were significantly 

greater than the upper layer of OU B Marine (category 

B). The resuspension of higher THg-sediment sediment 

was probably increasing the overall THg concentration of 

suspended solids present in the bottom layer. Settling of the 

suspended solids and deposition to OU B Marine sediment 

column should decrease STHg concentrations. The cumulative 

probability distribution of STHg of sediment collected after 

the study (2010) was significantly lower (p value=0.015) 

than that for sediments collected before the study. In the case 

of OU B Marine sediment, the difference in the cumulative 

distribution before and after the USGS study is confined 

to the trend of lower STHg concentration only above the 

median STHg concentration (50 percent on the cumulative 

probability distribution). 

Local settling of solids with high THg-concentrations 

solids discharged from several BNC sources could reverse the 

general positive effects of settling of low-THg concentration 

suspended solids in the water column. For instance, both the 

total organic carbon content and the STHg concentrations 

in grid cell 39, the cell in which stormwater drain PSNS015 

solids are discharged, increased two-fold or more between 

2007 and 2010. The effect of these BNC sources of PTHg on 

THg sedimentation can be assessed when THg concentrations 

of dry dock solids not affected by bias of sequential sampling 

during changing TSS conditions and of steam plant solids 

from the current reverse-osmosis system are obtained.
54 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_fig19

EXPLANATION

Upper SI-OUT

Upper SI-PO

Upper SI-IN

Sediment: Greater Sinclair Inlet (2003, 2005, 2007)

Sediment: Greater Sinclair Inlet (2010)

Solids suspended in the upper layer of greater Sinclair Inlet

0

0.2

0.4

0.6

0.8

1.0

0 0.5 1.0

Cumulative probability distribution

Total mercury concentration of solids, in milligrams per kilogram

Figure 19. Cumulative probability distribution of total mercury concentrations of solids suspended in the upper 

layer of the water column, of surface sediment (2003–07) and of surface sediment (2010) from greater Sinclair 

Inlet, Kitsap County, Washington.
Concentrations of Total Mercury of Solids Discharged to Sinclair Inlet 55

tac11-0637_fig20

0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4

Cumulative probability distribution

Total mercury concentration of solids, in milligrams per kilogram

EXPLANATION

Lower BNC-52/60

Lower BNC-39

Lower BNC-71

Solids suspended in the lower layer of OU Marine

Upper BNC-52/60

Upper BNC-39

Upper BNC-71

Sediment: OU B Marine (2003, 2005, 2007)

Sediment: OU B Marine (2010)

Solids suspended in the upper layer of OU Marine

Figure 20. Cumulative probability distribution of concentrations of total mercury of solids suspended in the upper 

layer of the marine water column (2008–09) and total mercury in sediment collected between 2003 and 2007, and in 

2010 from OU B Marine of the Bremerton naval complex, Kitsap County, Washington.
56 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Methylmercury in the Sinclair Inlet 

Drainage Basin

Methylmercury measurements were conducted as a 

preliminary survey of the occurrence and concentrations of 

FMHg in water sources to Sinclair Inlet, and therefore, are 

not suitable for a comprehensive mass balance of FMHg in 

Sinclair Inlet. 

Greater Sinclair Inlet

FMHg was detected by USGS in filtered freshwater 

from three storm drains (Sheridan Road in fig. 1, and Navy 

City and PO-Boat ramp in fig. 4) discharging outside of the 

BNC at a concentration of 0.06 ng/L (fig. 21). The median 

FMHg concentrations of six filtered effluent samples from 

the two wastewater treatment plants was 0.12 ng/L, ranging 

from 0.05 to 0.21 ng/L. A non-parametric correlation 

EXPLANATION

Filtered methylmercury, less than reporting level

Filtered methylmercury, greater than detection limit TW-T-01 TW-T-02

TW-T-03TW-T-04TW-T-05

M J A AJM

GorstGorst

Bremerton

Port Orchard

Bremerton West Sound

Utility District

Anderson

Blackjack

Annapolis

Olney

GREATER SINCLAIR INLET BASIN

Bremerton naval complex

Storm drains

Storm

drains

Wastewater treatment

plants

Streams

Industrial Wells

sources

Intertidal piezometers

Methylmercury, in nanograms per liter

Methylmercury, in nanograms per liter

0.3

0

0.3

0

0.6

0.9

1.2

1.5

PSNS015PSNS124

PSNS124.1

DD1–5

DD6

Steam plant

OUA-206

OUSC-380

OUBT-718OUBT-722OUBT-724

0.3

0

Figure 21. Methylmercury concentrations in terrestrial sources within the Bremerton naval 

complex (lower) and from basins of greater Sinclair Inlet (upper), Kitsap County, Washington. Note 

that the two bar graphs are the same scale, but the scale for intertidal piezometersTW-T05 extends 

to 1.5 ng/L. The three bars for the wastewater treatment represent data collected by USGS in 

May (M), July (J), and August (A) 2009. 
Methylmercury in the Sinclair Inlet Drainage Basin 57

analysis (Kendall tau) was performed using redox-sensitive 

constituents (DOC, ammonia, nitrite, iron and manganese) 

as independent variables. These reduced biogeochemicals 

are indicative of the chemically-reduced conditions that are 

generally associated with biogeochemical transformation 

of mercury to methylmercury (Marvin-DiPasquale and 

Agee, 2003). The correlation analysis indicated that neither 

the FMHg concentration nor the ratio of FMHg to FTHg 

was significantly correlated with these constituents. In the 

contrast, the consistent increase of FMHg concentrations in 

wastewater effluent samples from May to July to August, 

2009, strongly suggests that ambient temperature may be the 

primary factor controlling MHg concentration in such waters 

(Gbondo-Tugbawa and others, 2010).

Water from Gorst, Anderson, Blackjack, Annapolis and 

Olney Creeks (fig. 5) were sampled in May and July 2008. 

In 6 of the 10 filtered creek samples FMHg was measured 

at concentrations ranging from 0.05 to 0.11 ng/L (fig. 21). 

In contrast to wastewater effluents, the non-parametric 

correlation analysis of the results of the 10 stream samples 

(table 9) indicates that filtered total iron concentrations 

are significantly correlated with FMHg concentrations 

(p value=0.029), as was observed by Balogh and others 

(2004). However, the finding that FMHg is not correlated 

with DOC (p=0.11) is contradictory to a number of 

studies that have found correlations between MHg and 

DOC in freshwaters (Babiarz and others, 2001; Shanley 

and others, 2002). In contrast, the ratio of FMHg to FTHg 

was correlated with DOC (p value = 0.029), filtered nitrite 

(p value=0.047), total iron (p value = 0.005), and total 

manganese (p value=0.029). 

Bremerton Naval Complex 

FMHg was not detected in most of the sources of water 

discharging to Sinclair Inlet from the BNC. FMHg was not 

detected at a reporting level of 0.04 ng/L in water discharged 

from six BNC outfall systems including sump water from two 

dry dock relief drainage systems; the industrial effluent from a 

steam plant sampled during April 2008; and three stormwater 

drains sampled on January 7, 2009 (fig. 21). 

FMHg was only detected in groundwater from the 

Vicinity of Site 2 and was not detected at a reporting level 

of 0.04 ng/L in groundwater from the Zone of Direct 

Discharge and the Capture Zone of the Sumps collected 

during April 2008. The estimated FMHg concentration in 

fresh groundwater from well OUBT-718 (0.05 ng/L) was 

slightly above the reporting level. The detection of FMHg 

in well OUBT-718 was not associated with an elevated 

THg concentration (0.8 ng/L), but it was associated with 

reducing conditions inferred from the presence of reduced 

species including hydrogen sulfide, ferrous iron, filtered 

total manganese, and filtered ammonia. In contrast to well 

OUBT-718, groundwater from well OUBT-722 was saline and 

oxygenated. FMHg in groundwater from well OUBT-722 was 

0.10 ng/L, whereas the FTHg concentration was 581 ng/L. 

FMHg was measured once in saline water collected 

from the five piezometers monitored during the intertidal 

study in June 2009 (fig. 5). FMHg concentrations in the four 

westernmost piezometers ranged from 0.09 to 0.28 ng/L, even 

though THg concentrations in these four samples ranged from 

0.21 to 2.30 ng/L. The easternmost piezometer (TW-T05) 

near the seawall contained the highest FMHg concentrations 

of groundwater found on the BNC (1.5 ng/L) with a 

corresponding FTHg concentration of 244 ng/L. Although 

no chemical data on redox-sensitive species were collected 

during the intertidal study, anecdotal observations indicate that 

reduced Fe was present in groundwater from this piezometer 

because: (1) the particles collected on the two filters from 

this piezometer were bright red-orange and (2) the filtered, 

unacidified samples delivered to the laboratory had a strong 

reddish color several hours after filtration that disappeared 

upon acidification. These two observations suggest the 

presence of ferric iron from the oxidation of reduced ferrous 

iron formed in the soils of the intertidal zone. Thus, the 

chemistry of water collected from piezometer TW-T05 

resembled the chemistry of porewater from reduced marine 

sediments of Sinclair Inlet (Huffman and others, 2012) more 

than the oxygenated groundwater found throughout most of 

the BNC. 

Table 9. Non-parametric correlation statistics of filtered 

methylmercury concentrations relative to concentrations of 

reduced biogeochemicals.

Reduced 

biogeochemical

Kendall Tau correlation coeffecient

(p value)

Filtered 

methylmercury

Ratio of filtered 

methylmercury to 

filtered total mercury

Organic carbon 0.48 (0.11) 0.54 (0.029)

Ammonia 0.08 (0.86) 0.07 (0.86)

Nitrate plus nitrite -0.03 (1.00) 0.18 (0.48)

Nitrite 0.34 (0.29) 0.55 (0.047)

Iron 0.61 (0.029) 0.70 (0.005)

Manganese 0.43 (0.16) 0.54 (0.029)
58 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Sinclair Inlet Sediment

FMHg concentrations in 5 of the 24 porewater samples 

collected from OU B Marine and greater Sinclair Inlet 

exceeded 10 ng/L. The maximum FMHg concentration of 

28 ng/L (table 10) was measured at marine sediment station 

SI-IN in August 2008 . Median FMHg concentrations 

for porewaters collected from each OU B Marine station 

ranged from 0.09 to 1.1 ng/L. In contrast, the median FMHg 

concentrations for stations SI-IN and SI-PO were about 

10 ng/L. The median FMHg concentration of porewaters from 

the open water SI-OUT was 0.10 ng/L. 

Synthesis of Methylmercury in Sinclair Inlet

FMHg was generally not detected or measured at 

concentrations less than 3 times the reporting level (0.04 ng/L) 

in fresh surface water discharging into the Sinclair Inlet. 

Of the industrial discharges, stormwater samples, and 

groundwater samples collected within the BNC, FMHg 

was only found in groundwater in the Vicinity of Site 2 and 

was associated more with reducing conditions in non-saline 

groundwater or saline intertidal water than with high FTHg 

concentrations. The highest concentration of FMHg was 

collected in groundwater that appeared to contain reduced 

iron. The highest median FMHg concentration for a source 

category was measured in wastewater-treatment plant effluent 

(0.12 ng/L). The source category with the next highest median 

FMHg concentration was rainwater (0.08 ng/L). The median 

concentration of FMHg in creek water was 0.06 ng/L. Of 

the five streams, Blackjack Creek had the highest FMHg 

concentration (0.11 ng/L). The fraction of FTHg in the FMHg 

form in creek water was more highly correlated with reduced 

biogeochemicals than were the absolute concentrations of 

FMHg. The highest FMHg concentrations of the study were 

detected in porewater of highly reducing sediment collected 

from OU B Marine and greater Sinclair Inlet. 

Observations Indicating the Need for 

Further Study

To fully assess present-day sources of mercury to Sinclair 

Inlet, the need to fill significant data gaps became apparent 

during the course of this project. In November 2011, the U.S. 

Navy requested that the USGS collect additional data to fill 

these data gaps. Sample collection was completed in March 

2012. When laboratory analyses have been received and the 

data have been synthesized, a supplement to this report that 

includes additions and revisions to this report (for example, 

table 4) will be published as a separate document.

Groundwater

Well OUBT-722 was constructed in fill material adjacent 

to Site 2 of the Initial Assessment Study (URS Consultants, 

Inc., 1991). Likewise, wells OUBT-709 and OUBT-724 were 

constructed in fill material indentified as Site 10 C and Site 

10 E in the Site Inspection (U.S. Navy, 1992). Similar to 

the physical conditions at Site 2, tidal flushing of seawater 

through the storm drains around OUBT-709 and OUBT-724 

may facilitate the release of mercury from fill material, albeit 

at a lower rate than the much larger and deeper PSNS015 

storm drain. If the elevations of storm drains around wells 

OUBT-709 and OUBT-724 are higher than the elevations 

of the PSNS015 stormwater drain system, then release from 

Site 10 C and Site 10 E would occur only during the highest 

tidal elevations. Two observations related to wells OUBT-724 

and OUBT-709 suggest occasional release of THg may be 

occurring from fill material other than that from than Site 2. 

The high WTHg concentration of 5,240 ng/L in groundwater 

from OUBT-724 collected by the LTMP on October 18, 2005 

appears to have been collected at the highest tidal elevation 

of all samples collected from this well. However, the U.S. 

Navy reported no other WTHg concentration that was 

acceptable according quality-control criteria for a detection 

limit of 200 ng/L through October 2007. Using more sensitive 

analytical measurements, WTHg concentrations of 41.6 and 

27.5 ng/L were reported by the LTMP in 2008 and 2009, and 

this study reported FTHg concentrations of less than 10 and 

6.52 ng/L in 2008. 

Other than groundwater collected from OUBT-722, 

the highest FTHg concentration in groundwater collected 

on the BNC during this study (31 ng/L) was collected from 

OUBT-709 during winter when groundwater elevations 

Table 10. Concentrations of filtered methylmercury in 

porewaters from three stations in the Bremerton naval complex 

and three stations in greater Sinclair Inlet, Kitsap County, 

Washington, August 2008–August 2009.

[Numbers after BNC stations refer to the grid cell shown in figure 5. 

Abbreviations: FMHg, filtered methylmercury; ng/L, nanogram per liter; 

SI, Sinclair Inlet; OUT, Outer; IN, Inner; PO, Port Orchard; BNC, Bremerton 

naval complex; –, not applicable]

Field identifier Median Range

FMHg porewater concentrations, ng/L

SI-OUT 0.10 0.08–0.58

SI-IN 10.18 0.1–28

SI-PO 10.40 0.07–20

BNC-39 0.33 0.14–0.63

BNC-52 0.09 –

BNC-60 1.1 0.24–15

BNC-71 0.88 0.09–1.5
Summary 59

were higher than those during the April sampling (FTHg 

of 5.76 ng/L). Thus, it is possible that WTHg and FTHg 

concentrations in OU B Terrestrial wells may be related to the 

difference between tidal elevation and the elevation of storm 

drains servicing adjacent paved areas. 

Industrial Sources

The highest concentrations of THg of solids discharged 

from the dry docks sumps were measured in samples with 

the low TSS concentrations. However, this observation might 

be an artifact of changing TSS concentrations during the 

pumping cycle. If the release of a small loading of solids with 

a higher THg concentration on the particles is of concern, 

several measurements of THg concentrations of solids can 

be collected over the pumping cycle by collecting particulate 

THg and TSS from the same sample container. 

The highest concentration of filtered THg in a permitted 

source was found in the effluent from the steam plant. 

However, loadings calculations of THg reported in this 

study probably do not reflect the current loadings of THg 

from the steam plant operating with the new reverse osmosis 

demineralization plant. Re-sampling of effluent from the steam 

plant would provide a more representative estimate of current 

THg loadings from the steam plant.

Streams

Concentrations of FTHg and THg of solids in five 

creeks used in the mass loading calculations were measured 

during base flow conditions in May and July 2008. FTHg 

concentrations in creek water were significantly less than 

THg concentrations in rainfall indicating that the watersheds 

retained most of the THg falling on the landscape. During the 

flow conditions in wetter or storm conditions when most of the 

discharge occurs, more overland flow also occurs. Thus, less 

THg in rainwater is retained by watersheds than that retained 

during base flow conditions. Collecting FTHg and THg of 

solids during wet weather conditions will provide a better 

estimate of annual THg loadings to greater Sinclair Inlet. 

Summary 

A mass balance of any constituent in an estuary requires 

simultaneously balancing water, salt, and solids for the estuary. 

Previous data on the salinity distribution and long‐term flows 

in Sinclair Inlet allow the 98 cubic meter per second estimate 

of net flux of water entering Sinclair Inlet from Puget Sound 

to be constrained to within a factor of two. In contrast, the 

sources of most of solids depositing to sediment of Sinclair 

Inlet are unknown. In order to maximize the use of previously 

collected data and data collected by U.S. Geological Survey 

between 2007 and 2010, a quantitative mass balance of filtered 

total mercury (FTHg) was conducted along with a qualitative 

comparison of total mercury (THg) concentrations of various 

suspended solids and of marine sediment. A preliminary 

survey of FMHg concentrations in water sources to Sinclair 

Inlet was also conducted. The ability to predict the recovery 

of mercury in Sinclair Inlet sediment (whether a source of 

solids is likely increasing or decreasing THg concentrations 

in the upper layer of the marine sediments) requires additional 

information on the physical oceanography and sediment 

transport of Sinclair Inlet. 

Most FTHg in Sinclair Inlet originates from salt water 

flowing from Puget Sound. Atmospheric, terrestrial, and 

sedimentary sources contribute approximately 420 grams of 

FTHg per year and increase FTHg concentrations in Sinclair 

Inlet to 0.33 nanograms per liter from the 0.2 nanograms per 

liter in Puget Sound seawater entering Sinclair Inlet. The two 

major sources of FTHg within the Sinclair Inlet watershed are 

(1) diffusion from marine sediment and (2) discharge from 

the largest stormwater drain systems on the Bremerton naval 

complex (BNC) that pass through a zone of contaminated soil, 

albeit numerical values of these sources are highly uncertain. 

The category of sources with second largest loadings of FTHg 

include (1) THg in rain falling directly on Sinclair Inlet, 

(2) discharge from creek, and (3) discharge from stormwater 

basins outside of the BNC. Much of the THg falling in 

rainwater on the creek basin is retained by the creek basins. 

A municipal wastewater treatment plant, the effluent from the 

steam plant on the naval base, and the discharges from two 

naval dry dock systems constitute the category of the third 

largest loadings for individual sources. Stormwater discharged 

by the shipyard and groundwater discharge from the base 

do not seem to be significant sources of FTHg, although 

conflicting data prompted additional studies in 2011.

THg concentrations of solids from streams, stormwater, 

and wastewater effluent discharging into greater Sinclair 

Inlet were similar to THg concentrations of solids suspended 

in the upper layer of greater Sinclair Inlet. In contrast, four 

sources of solids (tidal flushing, stormwater discharge of 

Puget Sound Naval Shipyard, discharge from the dry docks 

and discharge from the steam plant) that discharged less 

than 1 percent of the solids depositing within Operable Unit 

(OU) B Marine sediments had THg concentrations greater 

than THg concentrations of solids suspended in the water 

column. The settling of these high-THg concentrations could 

be inhibiting the recovery of the total mercury concentration 

of sediment (STHg) within OU B Marine. The cumulative 

probably distribution of STHg in sediment of OU B Marine 

moved to lower concentrations in 2010 compared to 2003–07 

and indicated settling of solids from the water column is 

decreasing STHg concentrations, especially in sediment with 

the highest STHg. In contrast, sediment near the discharge 

point of the PSNS015 storm drain showed the highest increase 

in STHg within the OU B Marine in 2010. This increase 

near the largest source of mercury from the BNC deserves 

further attention.
60 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

FMHg was detected at low concentrations in storm 

drains, creeks, and wastewater effluent discharging to greater 

Sinclair Inlet. Temperature seemed to be controlling FMHg 

in wastewater effluent, while reduced ferrous iron was 

associated with FMHg concentrations in streams. FMHg was 

not detected in any of the storm drains or industrial BNC 

sources discharging to Sinclair Inlet. The highest FMHg 

concentrations were associated with porewaters in highly 

reducing sediment and intertidal groundwater. 

Former Site 2 is the major source of mercury 

discharged from the BNC to Sinclair Inlet, as previous U.S. 

Navy groundwater data from well LTMP-3 and previous 

ENVironmental inVESTment program stormwater drain data 

from PSNS015 have suggested. The site contributes a major 

fraction of the FTHg added to Sinclair Inlet from atmospheric, 

terrestrial, and sedimentary sources. Tidal flushing of large 

amounts of seawater into the PSNS015 storm drain with some 

subsequent leakage into the aquifer facilitates the extraction 

of THg from contaminated soils. FTHg is then released to 

Sinclair Inlet through the intertidal area at the end of the 

seawall and from the storm drain. A subterranean estuary 

in the stormwater drain retains THg in the storm drain until 

the stratification in the subterranean estuary destabilizes 

and possibly causes episodic releases of FTHg. High 

concentrations of THg of solids also are being released during 

tidal flushing and could be the cause of the increasing STHg 

concentration in adjacent marine sediments. During the final 

stages of this investigation, a separate release mechanism of 

THg associated with freshwater was detected associated with 

is this and needs further evaluation.

Acknowledgments

The authors would like to thank Patric Coxon and the 

staff of the City of Bremerton Wastewater Treatment Plant 

and Lance Hunt and the staff of the West Sound Utility 

District Wastewater Treatment Plant for collection of final 

wastewater effluent. Current and former U.S. Geological 

Survey Washington Water Science Center (WAWSC) staff 

Brietta Carter, James R. Foreman, Sarah A. Henneford, 

and Karen L. Payne assisted in the sampling of stream and 

stormwater. Current and former U.S. Geological Survey 

WAWSC staff James R. Foreman, Morgan E. Keys, Cg Laird, 

Karen L. Payne, Kelly L. Scholting, and Gary L. Turney 

assisted in sampling groundwater and industrial sources at 

BNC. Current and former U.S. Geological Survey WAWSC 

staff James R. Foreman and John Sottilare; and Wisconsin 

Mercury Research Laboratory (Middleton, WI) staff David 

P. Krabbenhoft, Jacob, M. Ogorek, and Thomas G. Sabin 

assisted in the collection of marine water column samples. 

U.S. Geological Survey WAWSC staff James R. Foreman, 

Cg Laird, and Richard W. Sheibley, U.S. Geological Survey 

National Research Program (Menlo Park, CA) staff Mark 

Marvin-DiPasquale and Jennifer L. Agee, and Wisconsin 

Mercury Research Laboratory (Middleton, WI) staff David P. 

Krabbenhoft Jacob, M. Ogorek and Thomas G. Sabin assisted 

in collection of sediment for porewater analysis and core 

incubation experiments. U.S. Geological Survey WAWSC 

staff Greg B. Justin and Peter H. Laird and former U.S. 

Geological Survey Columbia River Research Laboratory staff 

Gray L. Rust operated boats for collection of marine water 

and sediment. Former U.S. Geological Survey WAWSC staff 

Kelly L. Scholting oversaw the processing of samples for 

TSS analyses, weighed all filters, and calculated the final 

TSS results with laboratory assistance from Cg Laird and 

Karen L. Payne. Current and former U.S. Geological Survey 

WAWSC staff Brietta Carter, James R. Foreman, Morgan E. 

Keys, Karen L. Payne, Richard W. Sheibley and Kelly L. 

Scholting assisted in the laboratory processing of marine 

surface, porewater and incubation cores. Wisconsin Mercury 

Research Laboratory (Middleton, WI) staff Jacob, M. Ogorek, 

Thomas G. Sabin and Charles D. Thompson performed the 

analysis of FTHg, FMHg and PTHg. Jim Dobbs of the NWQL 

analyzed FTHg in groundwater and industrial sources. The 

data on marine currents in Sinclair Inlet analyzed in this 

report was collected in 1994 by a consortium of researchers 

from the U.S. Geological Survey. Former USGS employee 

Jeff Gartner provided access to the data archive for the 1994 

ADCP deployments.

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Appendix A 65

Appendix A. Data From U.S. Navy and Environmental Investment Projects 

Site 2 Soils Data

Concentrations of THg (table A1) in the soils from the 

monitoring wells and boreholes were measured by Inductively 

Coupled Plasma (ICP) (Method 6010, U.S. Environmental 

Protection Agency, 1986). Samples were processed within the 

required holding times. The initial and continuing calibration 

verification criteria for THg were met. The contract required 

detection limit (CRDL) standards, interference check samples 

(ISC), laboratory control samples (LCS), and the matrix spike 

samples (MS) all fell within the acceptable recovery range 

and duplicate sample RPD calculations were within control 

limits. Continuing calibration blanks were not run. THg was 

not detected in the field blanks or preparation blanks. In the 

field, replicate samples were collected at PS02-MW01 and 

PS02-MW04W (fig. 5), with a relative percent difference of 

25 and 18 percent respectively (U.S. Navy, 1992).

Analysis of WTHg Concentrations in Freshwater 

by the ENVironmental inVESTment project

Unfiltered surface-water samples (streams and storm 

drains) and wastewater effluent were collected during the 

ENVVEST project from 2002 to 2005 and analyzed at Battelle 

Marine Sciences Laboratory in Sequim, Washington, using 

cold vapor atomic fluorescence spectrometry (CVAFS) in 

accordance with Battelle SOP MSL-I-013, Total Mercury in 

Aqueous Samples by CVAFS, following U.S. Environmental 

Protection Agency method 1631, revision E (ENVironmental 

inVESTment Project, 2006). The collection of quality control 

samples included equipment, method, and laboratory controls 

blanks to indicate bias and contamination; field and laboratory 

replicates to indicate precision; and standard reference 

samples to indicate accuracy. 

The equipment blanks apparently were processed in the 

field, thus providing a measure of bias and contamination from 

both the equipment and the field sampling and processing 

procedures. Method blanks and blanks for recovery of 

laboratory controls were processed in the laboratory to 

indicate bias and contamination that may exist in the analytical 

procedures. The quality of equipment blanks processed 

in 2002 was excellent and the quality of method blanks 

processed from 2002 through 2005 was generally quite good. 

In 2002, six WTHg concentrations associated with equipment 

blanks were less than 0.5 ng/L, while the WTHg concentration 

for the 2005 equipment blank sample was 0.277 ng/L 

(table A2). In 2003, 2004, and 2005, WTHg was not detected 

in 14 of the 19 method blanks at reporting level that ranged 

from 0.1 to 0.17 ng/L. The maximum WTHg concentration in 

the five method blank samples was 0.221 ng/L. The median 

blank concentration for recovery of laboratory control samples 

(LCS) from 2002 through 2005 was 0.293 ng/L. Project 

reporting limits from 2002 through 2005 ranged from a 

minimum 0.38 ng/L in 2004 to 0.541 in 2005. 

Table A1. Concentrations of total mercury in soils from 

boreholes and the construction of monitoring wells in Site 2 during 

the Initial Assessment Study in 1990, Kitsap County, Washington.

[Data source: U.S. Navy (1992). Locations are shown in figure 5. Location 

name: PS02, site 2 of Initial Assessment Study; MW, monitoring well; H, 

borehole. Abbreviations: ft, foot; mg/kg, milligram per kilogram]

Location 

name

Date 

collected

Depth 

range

(feet)

Total 

mercury

(mg/kg)

PS02-MW01 06-20-90 2–4 24

06-20-90 2–4 31

06-21-90 18–20 29

06-21-90 23–24 16

PS02-MW02 06-22-90 18–20 26

06-22-90 22–24 20

PS02-MW03 06-25-90 2–4 24

06-25-90 12–14 21

06-25-90 20–22 29

PS02-MW04W 06-26-90 2–4 31

06-26-90 8–10 24

06-26-90 14–16 31

06-26-90 14–16 26

PS02-MW05 06-21-90 2–4 22

06-21-90 32–34 25

06-21-90 37–38 21

H-101 06-14-90 26–28 25

06-14-90 30–32 11

H-102 06-12-90 2–4 18

06-12-90 14–15 18

06-12-90 16–18 16

H-104 06-19-90 2–4 14

06-19-90 16–17 16

06-19-90 19–20 7.9

H-105 06-14-90 19–20 15

06-14-90 24–25 12

H-106 06-19-90 16–18 6.6

06-19-90 16–18 15

06-19-90 20–22 16

H-107 06-19-90 13–14 18

06-19-90 15–16 17

H-108 06-15-90 14–18 15

06-15-90 19–20 13

H-110 06-20-90 11–12 13

06-20-90 15–16 11

H-111 06-15-90 14–16 14

06-15-90 17–18 13

H-113 06-20-90 12–13 13

06-20-90 14–16 12

H-115 06-26-90 2–14 29

06-26-90 11–12 20

06-26-90 13–14 17

Minimum 6.6

Maximum 31

Median 17.5
66 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Thirteen laboratory replicates were processed to 

determine precision of laboratory procedures, and results were 

within the expectations of the project data-quality objectives. 

The results provide an indicator of precision and were within 

the project data-quality objective acceptance criteria of 

30 percent for replicate precision. Relative percent differences 

of WTHg concentrations in replicate sample ranged from 0 to 

28.1 percent and the median relative percent difference was 

8.8 percent (table A3).

Standard reference materials (SRM) were analyzed at 

the laboratory to determine accuracy of analytical procedures. 

Percent differences between the analytical results and the SRM 

certified value ranged from 0.2 to 10.3 percent (table A4). The 

median percent difference was 2.9 percent. These percentages 

are well within the project data quality objectives acceptance 

criteria of 20 percent. 

Matrix spike samples were analyzed and the percent 

recovery serves as a measure of accuracy of the analytical 

procedures. Additionally, the matrix spikes were analyzed 

in duplicate pairs, thus providing another measure of 

precision for the pair of matrix spike recoveries. Percent 

recoveries of WTHg in matrix spike samples ranged from 

79.3 to 116.3 percent (median: 102 percent) and were 

within the project data quality objectives acceptance criteria 

of 70–130 percent (table A5). Precision of the matrix 

spike duplicates ranged from 1.7 to 19.4 percent (median: 

2.0 percent) and were within the project data quality objectives 

acceptance criteria of 30 percent.

Concentrations of THg and ancillary date in unfiltered 

creek water are presented in table A6. The statistics for the 

regression of WTHg versus TSS concentrations are given in 

table A7 and shown in figure A1. Concentrations of THg from 

samples collected from stormwater drains discharging outside 

of the BNC (table A8), wastewater treatment plant effluents 

(table A9), and BNC stormwater drains (table A10) are 

presented along with ancillary data. The regression of WTHg 

versus TSS are shown in figure A2.

Groundwater Data

Prior to 2008, all FTHg and WTHg concentrations in 

BNC groundwater sampled for Initial Assessment Study 

(1990), Site Investigation (1990–91), Remedial Investigation/

Feasibility Studies (1993–95), Synoptic groundwater 

Monitoring (1998–2002), and LTMP (2004–07) were analyzed 

by older, relatively insensitive cold-vapor atomic absorption 

spectrometric (CV-AAS) methods with minimum detection 

limits (MDL) on the order of 100–200 ng/L. FTHg was not 

detected in any of the 235 samples collected before 2004. 

Detection of WTHg concentrations above the MDL likely 

were caused by the presence of high concentrations of solids 

in the pumped groundwater for WTHg analysis as documented 

by high turbidity and high concentrations of TSS and total 

aluminum. Between 2004 and 2007, the MDL of the analysis 

of FTHg and WTHg in OU B Terrestrial groundwater was 

also between 100 and 200 ng/L (U.S. Navy, 2007a). One well 

(LTMP-3) contained FTHg concentrations from slightly higher 

than the MDL to about 5 times the MDL. Groundwater from 

two wells (LTMP-3 and -5) contained WTHg significantly 

higher than the MDL, whereas two other wells (LTMP-1 and 

410R) contained WTHg slightly higher than the MDL. 

Beginning in 2008, groundwater samples from the 

LTMP were analyzed by more sensitive cold-vapor atomic 

absorption fluorescence spectrometric methods (CV-AFS) 

with a MDL of 1 ng/L (table A11, U.S. Navy, 2009). THg was 

not detected in the trip blanks or the rinsate blanks. For 2008 

and 2009, all quality control samples were within the control 

limits. Results of samples from three wells with the highest 

concentrations greater than 10 ng/L (in order of LTMP-3, 

LTMP-1, LTMP‐5) confirm that results of earlier studies using 

the CV-AAS method was best limited to screening purposes. 

The quantitative use of earlier data generated by CV-AAS 

method should be conducted with extreme caution. 

During the autumn 2008, sampling a field duplicate of 

water from PS09-MW01B (RPD of 14) was collected two 

weeks after the first sample. The WTHg concentration of water 

from PS07-MW04 was lower than the detection limit. Samples 

from wells OUB-MW15 and PS07-MW03 yielded estimated 

positive values. All other 2008 WTHg samples yielded 

acceptable values greater than the 1ng/L reporting limit. 

Apart from the non-detectable concentrations measured 

for both field replicates from well PS07-MW04 sampled 

during spring 2009, all samples had acceptable values greater 

than the reporting limit. One well sampled in March 2009 

had duplicate WTHg concentrations lower than the MDL. All 

WTHg results from wells LTMP-3 and LTMP-5 are presented 

in table A12.
Appendix A 67

Table A2. Concentrations of total mercury in equipment, method, and laboratory-control blanks, by the 

ENVironmental inVESTment Project, 2002–05.

[Data Source: ENVironmental inVESTment Project (2006). Laboratory qualifier: U, analyte not detected at or above 

the method detection limit; J, analyte detected above the method detection limit, but below the reporting limit. 

Abbreviations: ng/L, nanogram per liter; –, not applicable]

Sampling event Date of 

collection

Sample

identifier

Mercury 

concentration 

(ng/L)

Laboratory 

qualifier

Equipment blanks

2002-Equipment blanks 09-16-02 EB-SW4-1 0.5 U

09-17-02 EB-M6-1 0.5 U

09-18-02 EB-PA-1 0.5 U

09-19-02 EB-LMK136-1 0.5 U

09-20-02 EB-SWPSNS2-1 0.5 U

2005-Storm season 12-03-04 BST12-RB 0.277 J

Method blanks

2002-Baseflow 10-2002 BLANK 100402 0.500 U

10-2002 BLANK 100702 0.500 U

10-2002 BLANK 100802 0.500 U

10-2002 BLANK 100902 0.717 –

2003-1,3 01-08-03 Method blank (5) 0.115 J

02-05-03 Method blank (6) 0.122 J

2003-2 01-23-03 Method blank (3) 0.108 U

2003-4 02-10-03 Mean method blank 0.088 U

2003-5,6,7 03-21-03 Method blank (3) 0.100 U

2004-1 05-06-04 Method blank (1) 0.173 J

2004-2 06-22-04 Method blank -1 0.191 J

06-23-04 Method blank -2 0.221 J

2004-3 12-02-04 Method blank -1 0.116 U

2004-Marine boundary event 1 07-13-04 Mean method blank 0.120 U

2004-Marine boundary event 2 12-03-04 Method blank -1 0.120 U

12-03-04 Method blank -2 0.120 U

12-03-04 Method blank -3 0.120 U

2005-Marine 1 02-20-05 Method blank 0.170 U

2005-Marine 2 03-11-05 Mean method blank 0.170 U

2005-Marine 3 03-30-05 Mean method blank 0.170 U

2005-Marine 4 04-07-05 Mean method blank 0.170 U

2005-Marine 5 06-29-05 Mean method blank 0.170 U

2005-Marine 6 09-26-05 Mean method blank 0.170 U

Laboratory Control blanks

2003-1,3 01-08-03 BLANK010703 0.270 J

02-05-03 BLANK020403 0.271 J

2003-2 01-23-03 BLANK012203 0.279 J

2003-4 02-10-03 BLANK020703 0.249 –

2003-5,6,7 03-21-03 BLANK032003 0.211 J

2004-1 05-06-04 BLANK050504 0.361 J

2004-2 06-22-04 BLANK062104 0.300 J

06-23-04 BLANK062204 0.302 J

2004-3 12-02-04 BLANK120104 0.293 J

2004-Marine boundary event 1 07-13-04 BLANK071204 0.263 J

2004-Marine boundary event 2 12-03-04 BLANK120204 0.301 J

2005-Marine 1 02-20-05 BLANK022105 0.205 J

2005-Marine 2 03-11-05 BLANK031005 0.308 J

2005-Marine 3 03-30-05 BLANK032905 0.262 J

2005-Marine 4 04-07-05 BLANK040605 0.398 J

2005-Marine 5 06-29-05 BLANK062805 0.363 J

2005-Marine 6 09-26-05 BLANK092305 0.400 J

Median 0.293
68 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table A3. Relative percent differences between replicate analyses of total mercury in 

unfiltered water, ENVironmental inVESTvestment Project, 2002–05.

[Samples analyzed at Battelle Marine Science Laboratories, Sequim, Washington. Data source: 

ENVironmental inVESTment Project (2006). Abbreviations: μg/L, microgram per liter; r or R, replicate; 

DUP, duplicate; – not applicable]

Sampling

event

Sample

date

Sample

identifier

Total

mercury 

concentration 

(μg/L)

Mean 

replicate 

concentration 

(μg/L)

Relative

percent 

difference 

2002 09-18-02 1783-297 r1 0.00214 – –

09-18-02 1783-297 r2 0.00241 0.00227 12.0

09-16-02 1783-179 r1 0.00228 – –

09-16-02 1783-179 r2 0.00239 0.00234 4.5

09-18-02 1783-274 r1 0.00079 – –

09-18-02 1783-274 r2 0.00105 0.00092 28.1

09-17-02 1783-240 r1 0.00678 – –

09-17-02 1783-240 r2 0.00592 0.00635 13.6

2003-1, 3 12-15-02 1937-29 r1 0.00923 – –

12-15-02 1937-29 r2 0.00923 0.00923 0.0

2003-2 01-11-03 1937-80 r1 0.00753 – –

01-11-03 1937-80 r2 0.00625 0.00689 18.6

2003-4 01-29–30-03 1937-358 r1 0.00546 – –

01-29–30-03 1937-358 r2 0.00544 0.00545 0.3

2003-5, 6, 7 02-16-03 1937-445 r1 0.00233 – –

02-16-03 1937-445 r2 0.00242 0.00237 3.8

2004-1 05-06-04 2140-59 R1 0.00430 – –

05-06-04 2140-59 R2 0.00427 0.00428 0.8

2004-2 06-22-04 2140*99 R1 0.02575 – –

06-22-04 2140*99 R2 0.02359 0.02467 8.8

06-23-04 2140*202 R1 0.02773 – –

06-23-04 2140*202 R2 0.03038 0.02906 9.1

2004-3 12-02-04 2140-244 0.01276 – –

12-02-04 2140-244DUP 0.01100 0.01188 14.8

2005 03-11-05 2318*176 R1 0.00754 – –

03-11-05 2318*176 R2 0.00728 0.00741 3.4

Median 8.8
Appendix A 69

Table A4. Percent differences of concentrations of standard reference materials for analysis of total mercury in water, 

ENVironmental inVESTvestment Project, 2002–05.

[Data Source: ENVironmental inVESTment Project (2006). Standard Reference Material 1641d analyzed at Battelle Marine Science 

Laboratories, Sequim, Washington. Abbreviations: ng/L, nanogram per liter; –, not available or applicable]

Standard Reference Material 1641d mercury in natural water

Sampling

event

Sample 

identifier

Analysis 

date

Total mercury 

concentration 

(ng/L)

Percent 

recovery 

Percent 

difference 

2002-Baseflow 1641d100402 – 1,495,663 94.1 5.9

1641d100702 – 1,609,726 101.2 1.2

1641d100802 – 1,595,292 100.3 0.3

1641d100902 – 1,592,628 100.2 0.2

Certified value 1,590,000 – –

Range ±40,000 – –

2003-1,3 1641d 010703 – 1,562,000 98.2 1.8

1641d 020403 – 1,754,294 110.3 10.3

Certified value 1,590,000 – –

Range ±40,000 – –

2003-2 1641d 012203 – 1,636,367 102.9 2.9

Certified value 1,590,000 – –

Range ±40,000 – –

2003-4 1641d 020703 – 1,439,385 90.5 9.5

Certified value 1,590,000 – –

Range ±40,000 – –

2003-5, 6, and 7 1641d 032003 – 1,503,042 94.5 5.5

Certified value 1,590,000 – –

Range ±18,000 – –

2003-Stormwater 1641d 012703 – 1,662,041 104.5 4.5

1641d 020403 – 1,754,294 10.3

Certified value 1,590,000 – –

Range ±40,000 – –

2004-1 1641d050404 05-06-04 1,573,000 98.9 1.1

Certified value 1,590,000 – –

Range ±18,000 – –

2004-2 1641d062104 06-22-04 1,624,000 102.1 2.1

1641d062204 06-23-04 1,587,000 99.8 0.2

Certified value 1,590,000 – –

Range ±18,000 – –

2004-3 1641d 120104 12-02-04 1,684,000 105.9 5.9

Certified value 1,590,000 – –

Range ±18,000 – –

2005 1641d031005 03-11-05 1,521,000 95.7 4.3

1641d031705 03-17-05 1,569,000 98.7 1.3

Certified value 1,590,000 – –

Range ±18,000 – –
70 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table A5. Percent recovery of matrix spikes and relative percent differences of matrix spike for analysis of total mercury in water 

measured by the Environmental iInVESTvestment Project, 2002–05.

[Data Source: ENVironmental inVESTment Project (2006). Samples analyzed at Battelle Marine Science Laboratories, Sequim, Washington. Minor differences 

in percentages are due to rounding. Abbreviations: μg/L, microgram per liter; – not available or applicable]

Sampling 

event

Sample 

identifier

Date of 

collection 

or analysis

Spiking 

level 

(μg/L)

Environmental 

concentration 

(μg/L)

Spike 

concentration 

(μg/L)

Spike 

recovered 

(μg/L)

Percent 

recovery 

Relative 

percent 

difference

2002-Baseflow ALT2-1 1783-193 09-16-02 0.0171 0.00501 0.0220 0.0170 99.4 –

ALT2-1 1783-193 MSD 09-16-02 0.0180 0.00501 0.0232 0.0182 101.1 1.7

OC-1 1783-281 09-18-02 0.0117 0.00172 0.0138 0.0121 103.2 –

OC-1 1783-281 MS 09-18-02 0.0126 0.00172 0.0146 0.0129 102.2 1.0

SWPSNS2-1 1783-309 09-18-02 0.0140 0.0211 0.0358 0.0147 105.0 –

SWPSNS2-1 1783-309 MSD 09-18-02 0.0143 0.0211 0.0345 0.0134 93.7 11.4

M7-1 1783-234 09-17-02 0.0115 0.000820 0.0127 0.0119 103.3 –

M7-1 1783-234 MS 09-17-02 0.0113 0.000820 0.0125 0.0117 103.4 0.1

M1-1 1783-218 R1 09-17-02 0.0111 0.000862 0.0122 0.0113 102.1 –

M1-1 1783-218 MS 09-17-02 0.0107 0.000862 0.0120 0.0111 104.1 1.9

2003-1, 3 CH-1 1937-19 01-08-03 0.0264 0.00444 0.0254 0.0210 79.4 –

CH-1 1937-19 01-08-03 0.0269 0.00444 0.0262 0.0218 81.0 1.9

2003-2 SC-2 1937-90 01-11-03 0.0122 0.00616 0.0190 0.0128 105.0 –

SC-2 1937-90 MS 01-11-03 0.0105 0.00616 0.0168 0.0106 101.4 3.5

2003-4 BL-4 1937-364 02-10-03 0.0171 0.00239 0.0202 0.0178 104.2 –

BL-4 1937-364 MS 02-10-03 0.0153 0.00239 0.0175 0.0151 98.3 5.8

2003-5, 6, and 7 CE-7 1937-538 03-21-03 0.0146 0.0112 0.0255 0.0143 98.2 –

CE-7 1937-538 03-21-03 0.0130 0.0112 0.0238 0.0126 97.1 1.0

2003-Stormwater PSNS 115.1 1937-153 01-21-03 0.0181 0.0196 0.0398 0.0202 111.7 –

PSNS 115.1 1937-153 01-21-03 0.0193 0.0196 0.0420 0.0224 116.3 4.0

PSNS 115.1 1937-284 01-21-03 0.0210 0.0140 0.0368 0.0229 108.8 –

PSNS 115.1 1937-284 01-21-03 0.0191 0.0140 0.0354 0.0215 112.3 3.1

2004-1 T1005 LMK 122 05-06-04 0.0108 0.0219 0.0323 0.0105 96.8 –

T1005 LMK 122 05-06-04 0.0102 0.0219 0.0318 0.0099 97.1 0.4

2004-2 T1011 B-ST/CSO16 06-23-04 0.0186 0.0338 0.0509 0.0170 91.7 –

T1011 B-ST/CSO16 06-23-04 0.0203 0.0338 0.0532 0.0193 95.4 4.0

T1014 LMK122 06-23-04 0.0192 0.0498 0.0694 0.0196 102.0 –

T1014 LMK122 06-23-04 0.0177 0.0498 0.0647 0.0148 83.9 19.4

2004-3 T1018 B-ST28 12-02-04 0.0063 0.0092 0.0154 0.0063 99.493 –

T1018 B-ST28 12-02-04 0.0059 0.0092 0.0149 0.0058 97.479 2.045

T1026 2140-248 12-02-04 0.0065 0.0085 0.0154 0.0070 108.009 –

T1026 2140-248 12-02/04 0.0061 0.0085 0.0149 0.0064 105.675 2.185

2005 G1200 1 B-WWTP 03-17-05 0.0180 0.0052 0.0244 0.0193 107.319 –

G1200 B-WWTP 03-17-05 0.0154 0.0052 0.0214 0.0162 105.619 1.597

Median 102.1 2.0

1

 Environmental concentration is qualified with a J remark code.
Appendix A 71

Table A6. Concentrations of total mercury, total aluminum, organic carbon and suspended solids in unfiltered creek waters 

draining into Sinclair Inlet by the ENVironmental inVESTment Project, Kitsap County, Washington, 2002–05.

[Source of data: ENVironmental inVESTment Project (2006). Stream locations are shown in figure 5. Abbreviations: ng/L, nanogram per liter; μg/L, 

microgram per liter; mg/L, milligram per liter; <, less than; –, not available or not applicable; ND, not detected]

Collection

date

Total concentrations

Comment Field notes Total 

mercury 

(ng/L)

Total 

aluminum 

(μg/L)

Organic 

carbon 

(mg/L)

Suspended 

solids 

(mg/L)

Anderson Creek

03-11-02 24.20 15,000 4.4 327 Wet base flow

09-18-02 1.20 123 0.6 3 Dry base flow

01-22-03 8.88 1033 5.0 44 Storm composite

01-29-03 5.53 908 3.9 16 Storm

01-30-03 5.45 1,365 – – Storm

02-16-03 3.87 960 – – Storm

01-17-05 12.05 2,050 6 88 Storm

01-17-05 11.40 2,000 5.8 59 Storm Independent sample collected at same 

time (2 samplers)

01-22-05 3.00 215 3.3 5 Storm

Annapolis Creek

09-18-02 1.13 55.8 2.3 ND Dry base flow

04-19-04 4.11 174.0 4.7 30 Storm

05-26-04 6.00 667.0 9.6 32 Storm

10-18-04 5.50 634.0 7.1 29 Average of field duplicates

01-17-05 27.31 3,800 8.0 153 Storm

01-22-05 4.49 199 6.1 8 Storm

Blackjack Creek

03-11-02 9.00 1,750 7.4 67 Wet base flow

03-12-02 5.27 670 – 13 Wet base flow

03-13-02 4.90 449 – 10 Wet base flow

09-16-02 1.39 90.3 3.1 2 Dry base flow

09-17-02 1.26 68.6 – 6 Dry base flow

09-18-02 1.06 64.4 – <2 Dry base flow

01-22-03 8.68 696 10.9 33 Storm composite

01-29-03 6.22 593 9.5 13 Storm

01-30-03 9.01 1,420 – – Storm

02-15-03 3.24 243 5.9 10 Storm

02-28-05 2.78 179 5.7 7 Storm

03-19-05 4.85 396 8.4 19 Storm

03-30-05 3.70 181 10.4 4 –

Upper Gorst Creek

03-11-02 11.20 1,810 5.1 51 Wet base flow

03-12-02 2.99 266 – 10 Wet base flow

03-13-02 3.69 243 – 7 Wet base flow

09-16-02 2.94 581 1.9 25 Dry base flow

09-17-02 2.89 697 – 57 Dry base flow

09-18-02 4.06 858 – 38 Dry base flow

09-18-02 0.91 61 1.4 1 Dry base flow

01-22-03 6.26 569 5.0 50 Storm composite

01-29-03 3.42 904 3.1 34 Storm

01-30-03 3.83 953 – – Storm

02-16-03 8.94 1,840 2.4 16 Storm

01-22-05 2.63 244 2.6 11 Storm

03-30-05 1.34 87 2.0 2 Dry base flow
72 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Collection

date

Total concentrations

Comment Field notes Total 

mercury 

(ng/L)

Total 

aluminum 

(μg/L)

Organic 

carbon 

(mg/L)

Suspended 

solids 

(mg/L)

Lower Gorst Creek at Sam Christopherson

01-16-05 10.93 1,560 4.9 107 Storm

01-17-05 9.29 1,390 4.8 63 Storm

01-22-05 2.66 189 2.9 8 Storm

Olney Creek

03-11-02 27.20 8,930 6.8 333 Wet base flow

09-18-02 1.72 168 1.3 8 Dry base flow

01-22-03 22.60 2,935 9.4 210 Storm composite

01-29-03 6.99 1,750 – 57 Storm

01-30-03 9.55 2,390 5.7 – Storm

02-15-03 8.01 1,250 5.6 63 Storm

02-28-05 7.49 1,190 3.7 59 Storm

03-19-05 16.96 2,640 5.9 151 Storm

03-30-05 2.05 228 3 6 Wet base flow

Summary statistics for all ENVVEST stream data

Number of samples 53 53 40.0 46

Average 6.91 1,315 5.10 51

Standard deviation 6.34 2,364 2.60 75

Minimum 0.91 55.8 0.6 1

Maximum 27.31 15,000 10.9 333

Table A6. Concentrations of total mercury, total aluminum, organic carbon and suspended solids in unfiltered creek waters 

draining into Sinclair Inlet by the ENVironmental inVESTment Project, Kitsap County, Washington, 2002–05.—Continued

[Source of data: ENVironmental inVESTment Project (2006). Stream locations are shown in figure 5. Abbreviations: ng/L, nanogram per liter; μg/L, 

microgram per liter; mg/L, milligram per liter; <, less than; –, not available or not applicable; ND, not detected]
Appendix A 73

Table A7. Regression of total mercury concentrations against total suspended solids concentrations in unfiltered water 

samples collected by the Environmental inVESTvestment Project, Kitsap County, Washington, 2002-05.

[Values in bold were significant at a probability level of 0.05. Abbreviations: ng/L, nanogram per liter; ng/mg, nanogram per milligram; CSO, 

combined sewer overflow; B, Bremerton; PSNS, Puget Sound Naval Shipyard; PO, Port Orchard; >, greater than; <, less than; –, not applicable]

Location 

name

Regression of total 

mercury versus 

total aluminum

Total 

suspended 

solids range 

(mg/L)

Regression of total mercury versus 

total suspended solids

p value Number of 

samples p value Correlation coefficient

Intercept

(ng/L)

Slope

(ng/mg)

Watershed

Blackjack <0.001 <2–67 12 <0.001 0.83 2.5 0.12

Anderson <0.001 3–327 7 <0.001 0.95 4.5 0.064

Olney 0.002 6–333 8 <0.001 0.98 2.5 0.082

Annapolis <0.001 1–153 6 0.001 0.99 0.92 0.17

Gorst Upper <0.001 1–57 12 0.11 0.49 4.38±1.21 –

Stormwater drains

CSO16 >0.001 <1–75 7 <0.001 0.97 0.37 0.42

LMK122 0.26 1–92 10 0.006 0.79 4.6 0.46

B-ST28 0.004 <1–116 7 0.034 0.97 2.16 0.19

PO-BLVD 0.04 6–149 4 0.002 0.99 4.45 0.10

LMK038 0.008 2–113 5 0.005 0.97 2.54 0.15

B-ST12 0.20 1–253 9 0.06 0.73 – –

PSNS015 0.23 26–168 5 0.03 0.92 -192 7.2

PSNS126 0.24 5–39 6 0.05 0.81 7.9 0.46

PSNS124 0.70 8–20 5 0.06 0.86 – –
74 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table A8. Concentrations of total mercury, total aluminum, organic carbon, and 

suspended solids in unfiltered stormwater draining into Sinclair Inlet measured by the 

ENVironmental inVESTment Project, Kitsap County, Washington.

[Data Source: ENVironmental inVESTment Project (2006). Stormwater locations are shown in 

figures 1, 2, and 3. Abbreviations: ng/L, nanogram per liter; mg/L, milligram per liter; <, less than; –, 

not available or not applicable; ND, not detected]

Collection date

Total concentrations

Total 

mercury 

(ng/L)

Total

aluminum 

(μg/L)

Organic

carbon

(mg/L)

Suspended 

solids

(mg/L)

CSO16 (B-CSO16 Bremerton, Pacific Ave.)

03-11-02 12.30 1,190 1.1 27

03-13-02 1.90 58 – ND

03-14-02 1.88 50 – ND

04-19-04 10.36 566.0 7.1 26

05-26-04 33.8 1,560 10.5 69

10-18-04 27.4 1,710 – –

02-28-05 32.8 2,390 7.5 75

03-19-05 15.1 1,720 4.3 51

LMK122 (Navy City Metals- Gorst Watershed)

03-12-02 9.63 2,150 3.9 45

03-13-02 6.23 1,510 – 15

03-14-02 5.03 689 – 9

09-16-02 2.34 69.3 3.7 ND

09-17-02 5.45 241 – 4

09-18-02 1.89 92.2 – 1

04-19-04 21.9 558 6.2 20

05-26-04 49.8 1,050 12.1 48

10-18-04 56.1 802 – –

01-16-05 41.9 2,640 7.3 92

01-22-05 14.1 642 6 8

ST-28 (Bremerton Callow Ave.)

03-11-02 6.90 1,057 1.6 24

03-13-02 2.41 120.0 – 2

04-19-04 13.28 1,230 10.4 79

05-26-04 25.27 2,670 16.8 116

10-18-04 9.17 1,168 6.4 31

02-28-05 18.40 2,150 11.7 81

03-19-05 11.06 1,750 5.7 49

PO-BLVD (Port Orchard, Port Orchard Blvd.)

05-26-04 19.52 3,265 20.5 149

10-18-04 8.46 1,270 6.1 46

01-17-05 12.95 2,230 6.6 87

01-22-05 5.46 419 5.7 6

B-ST12 (Bremerton Trenton Ave.)

09-16-02 1.17 111 1.9 ND

04-19-04 3.33 186 4.2 5

05-26-04 8.06 957 7.9 34

10-18-04 4.92 850 – –

03-19-05 5.25 597 3.4 205

03-26-05 5.91 776 2.6 28

03-30-05 44.78 9,930 3 253

03-31-05 9.66 575 2.5 16
Appendix A 75

Collection date

Total concentrations

Total 

mercury 

(ng/L)

Total

aluminum 

(μg/L)

Organic

carbon

(mg/L)

Suspended 

solids

(mg/L)

LMK038 (Manchester Outfall)

09-18-02 0.59 36.4 2.5 2

04-19-04 4.28 306 7.6 11

05-26-04 11.25 1,760 11 64

10-18-04 10.80 2,350 – –

01-17-05 19.23 3,420 6.7 113

01-22-05 6.25 415 6.8 8

Summary statistics for all ENVVEST greater Sinclair Inlet stormwater data

Number of samples 44 44 33 36

Average 14.05 1,347 6.7 52.8

Standard Deviation 13.67 1,608 4.3 57.4

Minimum 0.59 36 1.1 1.0

Maximum 56.14 9,930 20.5 253.0

Table A8. Concentrations of total mercury, total aluminum, organic carbon, and 

suspended solids in unfiltered stormwater draining into Sinclair Inlet measured by the 

ENVironmental inVESTment Project, Kitsap County, Washington.—Continued

[Data Source: ENVironmental inVESTment Project (2006). Stormwater locations are shown in 

figures 1, 2, and 3. Abbreviations: ng/L, nanogram per liter; mg/L, milligram per liter; <, less than; –, 

not available or not applicable; ND, not detected

Table A9. Concentrations of total mercury, total aluminum, organic 

carbon, and suspended solids in unfiltered effluents from two 

wastewater treatment plants ENVironmental inVESTment Project, 

Kitsap County, Washington, 2004–05.

[Data Source: ENVironmental inVESTment Project (2006). Abbreviations:

ng/L, nanogram per liter; mg/L, milligram per liter; –, not available]

Collection

date

Total concentrations

Total

mercury 

(ng/L)

Aluminum 

(mg/L)

Organic 

carbon 

(mg/L)

Suspended 

solids

(mg/L)

City of Bremerton 

05-26-04 17.7 41 15 10

10-19-04 5.62 30 13 –

03-01-05 8.45 27 13 2

03-30-05 34.8 169 11 3

West Sound Utility District 

05-26-04 8.17 98 20 20

01-17-05 32.93 645 25 82

01-22-05 11.58 98 19 14

03-01-05 7.54 50 16 8

03-19-05 6.60 49 19 12

03-26-05 7.15 43 15 9

03-30-05 4.46 19 16 26

04-10-05 39.83 424 17 104
76 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table A10. Concentrations of total mercury, total aluminum, organic carbon, and suspended 

solids in unfiltered stormwater draining from the Bremerton naval complex measured by the 

ENVironmental inVESTment Project, Kitsap County, Washington, 2002–05.

[Data Source: ENVironmental inVESTment Project (2006). Site identifiers are shown on figure 3. Abbreviations:

PSNS, Puget Sound Naval Shipyard; ng/L, nanogram per liter; mg/L, milligram per liter; <, less than; –, not 

available]

Date of 

sample

collection

Site 

identifier

Total concentrations

Total 

mercury 

(ng/L)

Total 

aluminum 

(mg/L)

Organic

carbon

(mg/L)

Suspended 

solids 

(mg/L)

PSNS015

01-21-03 PSNS015 26.09 472 – –

01-29-03 PSNS015 15.26 127 – –

04-19-04 PSNS015 181.25 889 5.1 46

05-26-04 PSNS015 1,131.02 2,000 14.5 168

10-18-04 PSNS015 125.00 2,600 5.6 88

02-28-05 PSNS015 65.51 734 7.0 26

03-19-05 PSNS015 116.62 583 6.7 34

Number of samples 7 7 5 5

Average 237 1,058 7.78 72

Standard deviation 398 898 3.84 59

Minimum 15.3 127 5.1 26

Maximum 1,131 2,600 14.5 168

All other PSNS stormwater drains

01-21-03 PSNS008 42.80 1,440 – –

01-29-03 PSNS008 4.92 110 – –

05-26-04 PSNS008 24.67 977 9.0 45

09-18-02 PSNS011 21.14 80 5.5 1

09-18-02 PSNS052 1.85 90 – –

01-21-03 PSNS081.1 22.02 311 – –

01-29-03 PSNS081.1 28.58 206 – –

01-21-03 PSNS101 5.94 131 – –

01-29-03 PSNS101 3.80 40 – –

05-26-04 PSNS101 15.86 145 3.7 32

01-21-03 PSNS115.1 19.56 223 – –

01-29-03 PSNS115.1 14.68 52 – –

05-26-04 PSNS115.1 24.80 129 6.4 5

01-21-03 PSNS115.1A 442.91 6,700 – –

01-29-03 PSNS115.1A 18.55 230 – –

01-21-03 PSNS124 14.11 262 – –

01-29-03 PSNS124 19.32 24 – –

04-19-04 PSNS124 116.31 168 9.3 20

05-26-04 PSNS124 44.01 200 14.4 17

10-18-04 PSNS124 34.75 195 8.9 12

02-28-05 PSNS124 17.23 102 6.1 8

03-19-05 PSNS124 20.46 105 3.8 8

09-18-02 PSNS126 14.77 102 5.3 5

01-21-03 PSNS126 13.04 687 – –

01-29-03 PSNS126 4.80 222 – –

04-19-04 PSNS126 21.12 338 14.0 25
Appendix A 77

Table A10. Concentrations of total mercury, total aluminum, organic carbon, and suspended 

solids in unfiltered stormwater draining from the Bremerton naval complex measured by the 

ENVironmental inVESTment Project, Kitsap County, Washington, 2002–05.—Continued

[Data Source: ENVironmental inVESTment Project (2006). Site identifiers are shown on figure 3. 

Abbreviations: PSNS, Puget Sound Naval Shipyard; ng/L, nanogram per liter; mg/L, milligram per liter; <, less 

than; –, not available]

Date of 

sample

collection

Site 

identifier

Total concentrations

Total 

mercury 

(ng/L)

Total 

aluminum 

(mg/L)

Organic

carbon

(mg/L)

Suspended 

solids 

(mg/L)

All other PSNS stormwater drains—Continued

05-26-04 PSNS126 27.70 814 20.9 39

10-18-04 PSNS126 12.80 728 7.3 24

02-28-05 PSNS126 11.77 677 9.5 17

03-19-05 PSNS126 27.50 770 17.3 36

05-26-04 PSNS126.1 44.13 159 – –

Number of samples 31 31 15.0 15

Average 36.64 530 9.4 20

Standard deviation 78.15 1,193 5.1 14

Minimum 1.85 24 3.7 1

Maximum 442.9 6,700 20.9 45
78 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

tac11-0637_figA-01

0

Total suspended solids, in milligrams per liter

Total mercury, in nanograms per liter

0 20 0

5

10

15

20

40

10

20

30

40

0

10

20

30

40

60 80 0 100 200 300 400

0 100 200 300 400

100

0 40 80 120 160 200 0

20

40

60

80

Gorst - Upper

Gorst - Lower

Annapolis

Olney

Annapolis regression

Olney regression

Blackjack

Regression

Anderson

Regression

EXPLANATION EXPLANATION

EXPLANATION EXPLANATION

Figure A1. Total mercury concentrations in unfiltered creek water compared to 

total suspended solids concentrations with regressions as described in table A7.
Appendix A 79

tac11-0637_figA-02

EXPLANATION

Total suspended solids, in milligrams per liter

Total mercury, in nanograms per liter

0 50 0

10

20

30

40

50

0

10

20

30

40

50

100

10

20

30

40

150 200 250 0 50 100 150 200 250

0 0 50 100 150 200 250

0 50 100 150 200 250 0

20

40

60

80

B-ST12

LMK038

Regression

LMK122 regression

LMK122

B-ST28

B-ST28 regression

PO-BLVD

PO-BLVD regression

Bremerton

CS016

Regression

EXPLANATION

EXPLANATION

011

008

PSNS

101

115.1

124

Regression

126

EXPLANATION

Figure A2. Total mercury concentrations in unfiltered stormwater compared to 

total suspended solids concentrations with regressions as described in table A7.
80 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table A11. Concentrations of total mercury in unfiltered groundwater samples collected 

from the Operable Unit B-Terrestrial by the Long Term Monitoring Program, 2008–09.

[Data source: Dwight Leisle, U.S. Navy, written commun., 2010. Abbreviations: ng/L, nanogram per 

liter; U, analyte not detected at or above the method detection limit; J, analyte detected above the method 

detection limit, but below the reporting limit; mg/L, milligram per liter; NTU, nephelometric turbidity units; 

LTMP, Long-Term Monitoring Program; OUB, operational unit B; PS, Puget Sound; –, not applicable]

Location 

name

Date sample 

collected

Total 

mercury

(ng/L)

Final 

qualifier

Total 

suspended 

solids 

(mg/L)

Turbidity

(NTU)

LTMP-1 10-14-08 156 – – 7

LTMP-2 10-14-08 4.74 – 65 0

LTMP-3 10-14-08 3,680 – 9 22

LTMP-4 10-16-08 3.61 – 13 28

LTMP-5 10-15-08 41.6 – 6 13

OUB-MW15 10-16-08 1.53 J – 0

OUB-MW18 10-20-08 1.41 – – 36

PS07-MW03 10-20-08 23.8 J 12 55

PS07-MW04 10-15-08 0.33 U – 28

PS09-MW01B 10-20-08 26.9 – 37 26

PS09-MW01B 11-05-08 30.9 – 40 30

LTMP-1 04-01-09 56.8 – – 19

LTMP-2 03-30-09 23.2 – – 15

LTMP-3 04-02-09 1,190 – – 30

LTMP-4 03-31-09 2.97 – – 38

LTMP-5 04-01-09 27.5 – – 34

OUB-MW15 03-30-09 2.59 – – 4

OUB-MW18 04-01-09 8.87 – – 25

PS07-MW03 03-30-09 1.93 – – 42

PS07-MW04 03-31-09 0.40 U – 7

PS09-MW01B 03-31-09 10.3 – – 42

Number of samples 21 7 21

Average 252 26 24

Standard deviation 826 22 15

Minimum 0.33 6 0

Maximum 3,680 65 55
Appendix A 81

Table A12. Concentrations of total mercury in unfiltered and filtered water and ancillary data from Long-Term Monitoring Program Wells LTMP-3 and LTMP-5 in Operable Unit B-Terrestrial, Bremerton naval complex, Kitsap County, Washington, 2004–07.[Data source: 2004-07 data, U.S. Navy (2007); 2008-09 data, U.S. Navy (2009); Dwight Leisle, U.S. Navy, written commun., 2010. Final qualifier: A, acceptable; J, estimated positive 

result; U, undetected; B, less than the reporting limit and greater than the instrument detection limit. Abbreviations: LTMP, Long-Term Monitoring Program; μg/L, microgram per liter; mg/L, milligram per liter; MP, measuring point; NGVD, National Geodetic Vertical Datum of 1929; MLLW, mean lower low water; –, not analyzed or does not apply]

Date 

collected

Time 

collected

Unfiltered 

mercury 

(μg/L)

Final 

qualifier

Filtered 

mercury 

(μg/L)

Final 

qualifier

Unfiltered 

aluminum 

(μg/L)

Final 

qualifier

Total 

suspended 

solids

(mg/L)

Turbidity

Water level

Below MP NGVD29 MLLW

LTMP-3 (well OUBT-722)

08-30-04 – 0.98 A – – 5 A – – – – –

08-30-04 – 2.4 A – – 5 A – – – – –

12-01-04 – 2.81 J – – – – – – – – –

12-01-04 – 2.89 J – – – – – – – – –

03-01-05 – 2.48 A 0.97 A 7 A – – – – –

05-12-05 – 6.69 A 0.69 A – – – – – – –

07-14-05 – – – 0.21 A – – – – – – –

07-14-05 – – – 0.21 A – – – 9.1 – -1.02 4.97

10-19-05 – 3.34 A – – 31 A 5.09 5.09 – 1.94 7.93

01-19-06 – 2.05 A – – – – 0 0 – 1.61 7.6

04-12-06 – 3.82 – – – 18 – 9 – 0.24 6.23

10-10-06 – 4.92 – – – 13 – 0.9 0.9 10.26 0.5 6.49

10-10-07 – 3.21 – – – – – 50 15 11.83 -1.07 4.92

10-14-08 1 12:21 3.68 – – – – – 9 22 12.87 -2.11 3.88

04-20-09 1 13:05 1.19 – – – – – – 30 9.78 0.98 6.97

N 13 4 6 5 8Average 3.11 0.52 13.2 13 11.4Standard 

deviation

1.5 0.38 10.1 21 10.4

Minimum 0.98 0.21 5 0 0Maximum 6.69 0.97 31 50 30
82 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10 Date collected Time collected Unfiltered mercury (μg/L) Final qualifier Filtered mercury (μg/L) Final qualifier Unfiltered aluminum (μg/L) Final qualifier Total suspended solids (mg/L) Turbidity Water level Below MP NGVD29 MLLW LTMP-5 (well OUBT-724) 08-19-04 – 0.5

A – – 5 A – – – – –

11-30-04 – 0.2

U – – – – – – – – –

02-28-05 – 0.23

A 0.2

U 2 A – – – – –

05-10-05 – 0.26

A 0.2

U – – – – – – –

07-14-05 – – – 0.2

U – – – 0 – -0.78 5.21

10-18-05 – 5.24

A – – 5 U 0.96 0.96 – 3.42 9.41

01-19-06 – 0.2

U – – – 0 0 – -0.22 5.77

04-17-06 – 0.2 – – – 5 – – 0 – -2.5 3.49

10-10-06 – 0.2 BJ – – 30 – 21.3 21.3 9.58 2.34 8.33

10-11-07 – 0.2

U – – – – 43 19 10.68 1.24 7.23

10-15-08 2 11:38 0.042 – – – – – 6 13 13.32 -1.4 4.59

04-01-09 2 14:55 0.028 – – – – – – 34 15.82 -3.9 2.09

N 11 3 5 5 8Average 0.67 0.2 9.4 14.3 11.0Standard 

deviation

1.52 11.6 18.2 12.9

Minimum 0.028 2 0 0Maximum 5.24 30 43 34

1One-third through ebbing cycle from higher low tide to higher high tide.2At lower high tide.

Table A12. Concentrations of total mercury in unfiltered and filtered water and ancillary data from Long-Term Monitoring Program Wells LTMP-3 and LTMP-5 in Operable Unit B-Terrestrial, Bremerton naval complex, Kitsap County, Washington, 2004–07.—Continued[Data source: 2004-07 data, U.S. Navy (2007); 2008-09 data, U.S. Navy (2009); Dwight Leisle, U.S. Navy, written commun., 2010. Final qualifier: A, acceptable; J, estimated positive 

result; U, undetected; B, less than the reporting limit and greater than the instrument detection limit. Abbreviations: LTMP, Long-Term Monitoring Program; μg/L, microgram per liter; mg/L, milligram per liter; MP, measuring point; NGVD, National Geodetic Vertical Datum of 1929; MLLW, mean lower low water; –, not analyzed or does not apply]
Appendix B 83

Figure B1. Lead-210 activity versus mass accumulation (locations 475 

and 490) for cores from the Remedial Investigation/Feasibility Study 

and the nearby ENVironmental inVESTment project core (S3). The 

re-evaluated sedimentation rates for cores from locations 475 and 490 

shown in the legend were calculated using only the part of the curve in 

which lead-210 activity decreases with increasing mass accumulation 

(data points with symbols).

Appendix B. Calculation of Sedimentation of Solids in Sinclair Inlet

The most common method used for 

estimating sedimentation rates involves carefully 

collecting a sediment core, measuring the mass 

of dry sediment for a series of vertical intervals 

in the core, and using low-radioactivity isotopes 

of lead (210Pb or lead-210) as a time marker in 

the core. The sediment core first is collected in 

a manner that does not disturb the sedimentwater interface. The core then is sectioned 

into numerous vertical intervals and multiple 

analyses are performed on each section. For 

most calculations of sedimentation rate, the 

mass of dry sediment for each vertical interval 

for a given area of sea floor, must be known. 

This measurement usually is made indirectly 

by measuring the percentages of water and dry 

solids in sediment from each vertical interval. 

The mass of sediment in each vertical section 

is added to the sum of the mass of solids in all 

sections above, to develop a curve of cumulative 

mass accumulation of solids with increasing 

depth in the core (fig. B1). 

The timing component of a sedimentation 

rate is commonly determined by defining the 

decrease of very low radioactivity of 210Pb 

(lead) with depth in the core due to radioactive 

decay. 210Pb is produced in small amounts in 

0 4 8 12 16

0

1

2

3

4

Location: sedimentation rate

ENVVEST S3: 0.141 g cm-2 yr-1

RI/FS 472: 0.093 g cm-2 yr-1

RI/FS 490 : 0.100 g cm-2 yr-1

Mass accumulation, in grams per square centimeter

Activity of lead-210, in disintergrations per minute per gram 

EXPLANATION

the atmosphere from the decay of atmospheric

222Rn (radon), and it is quickly scavenged onto 

atmospheric particles that settle onto water and 

land surfaces. Once in the water column of water 

bodies, 210Pb tends to quickly settle to the sedimentwater interface by attaching onto particles. Once 

delivered to the sediment column, the 210Pb on 

the particles is buried by deposition of newly 

settling particles. 210Pb decays with a half-life of 

22.6 years. Assuming that the sedimentation rate 

is constant, the depth in the sediment at which 

the 210Pb radioactivity decreases to half of the 

surface value represents 22.6 yr of sedimentation. 

The sedimentation rate based on 210Pb activity is 

calculated from the slope of the linear regression 

of the natural log of the “unsupported activity” of 

210Pb against the cumulative mass accumulation of 

sediment:

-2 -1

210

210

Sedimentation rate (gm cm yr )

0.0311/slope(log( Pb) vs.

cumulative mass accumulation),

where

0.0311 is related to the radioactive half-life of

Pb (that is, decay rate).

= −

(B1)
84 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

The “unsupported activity” of 210Pb is used because this 

measure corrects for the low levels of 210Pb in a blank sample 

as well as the 210Pb created by radium decay within the 

sediments. Note that the 210Pb activity decreases down the 

core, so the slope of the logarithmic of unsupported 210Pb is 

always a negative number. 

Other indirect methods based of the vertical profile of a 

variety of constituents in the core are often used to corroborate 

the results of the 210Pb method. The first appearance of 

elevated concentration of 137Cs (cesium) in 1953 (as a result 

of atmospheric testing of thermonuclear weapons) is often 

used as a time marker in the sediments. Likewise, the peak 

concentration of 137Cs in 1964, at the height of atmospheric 

testing before the Atmospheric Test Ban Treaty went into 

effect, is used as similar marker (Charles and Hites, 1987). 

Sometimes, the timing of increases of non-radioactive 

constituents to greater than natural levels can also be used as a 

time marker. In Sinclair Inlet, the increase of lead and mercury 

to greater than natural levels is associated with the opening of 

the Puget Sound Naval Shipyard (PSNS) in 1895. The better 

the agreement between various independent measurements, 

the more confidence one has in the value determined for the 

rate of sedimentation. 

Three cores offshore of OU B Marine were collected 

in 1995 by the U.S. Navy as part of the RI/FS (U.S. Navy, 

2002). Calculations based on the 210Pb profiles of cores off 

Pier D (location 490, cited by Paulson and others, 2010) and 

off Pier 6 (location 475 cited by Paulson and others, 2010) 

reported sedimentation rates were about 0.42 g cm-2 yr-1. 

However, the estimated rates were uncertain, because the 137Cs 

concentration peak was much shallower than expected from 

the 210Pb sedimentation calculations. One core (location 479 

cited by Paulson and others, 2010) showed a dramatic break in 

the 210Pb profile with depth. 

Sedimentation rates in five cores along the center axis of 

Sinclair Inlet were measured in 2002 (Crecelius and others, 

2003). The activity of 210Pb in the sediment core sections 

was determined by a more sensitive method than that used in 

the RI/FS, in which the granddaughter 210Pb alpha particle is 

counted on a silicon barrier diode detector. The sedimentation 

rates at the three cores offshore of OU B Marine (cores S2–S4 

cited by Paulson and others, 2010) varied between 0.14 and 

0.17 g cm-2 yr-1 (the top of core S4, collected adjacent to the 

area dredged in 2001 for the turning basin, was disturbed). 

In contrast, the sedimentation on the Gorst mudflats (core 

S1 cited by Paulson and others, 2010) was only 0.072 g cm-2

yr-1, while the sedimentation rate on the eastern side of OU B 

Marine (S5) was 0.11 g cm-2 yr-1. When the deepest vertical 

section where elevated total Pb and STHg concentrations 

were evident was assigned the date of 1895 (the opening of 

the PSNS), sedimentation rates for cores S1, S2, and S3 were 

comparable to the sedimentation rates calculated from the 

activity of 210Pb. However, this 1895 time marker method 

yielded higher sedimentations rates of 0.27 and 0.25 g cm2 yr-1

for cores S4 and S5, respectively. 

The sedimentation rates from the ENVVEST project 

were based on activity of 210Pb and ranged between 0.072 

and 0.17 g cm-2 yr-1, whereas the rates from the Remedial 

Investigation/Feasibility Study were about 0.42 g cm-2 yr-1. 

In order to investigate this discrepancy, the original 210Pb 

activity of cores from locations 475 and 490 from the RI/FS 

were plotted against cumulative mass accumulation along 

with the ENVVEST project core (S3) nearest to the RI/FS 

cores (fig. B1). The two data sets show some similarities 

and differences. Both data sets show a mixed surface layer 

where the activity of 210Pb, and thus the age of the sediments, 

remains fairly constant to a depth of about 4 cm (mass 

accumulation of about 2 g cm-2). Both sets of data also 

show a similar rate of decrease in the activity of 210Pb with 

increasing mass accumulation. However, the two data sets 

differ in the profile between 4 and 12 g cm-2. The ENVVEST 

data show a consistent decrease in the activity of 210Pb with 

increasing cumulative mass, while the Remedial Investigation 

data shows almost constant 210Pb activity. This difference in 

the 210Pb activity in the deeper part of the core is the reason 

why the calculated sedimentation rates from the two sets of 

cores differ. 

The data set used to calculate the slope of ENVVEST 

cores included as many points below the mixed layer that 

provided a consistent decrease in the activity of 210Pb with 

cumulative mass accumulation. In contrast, the data set used to 

calculate the slope of RI/FS cores contained data points from 

the entire core. Consequently, because the slope of the 210Pb 

activity versus cumulative mass accumulation curve in the 

RI/FS cores flattens out above 4 g cm-2, a larger sedimentation 

rate was estimated for the RI/FS cores. When the 210Pb data 

from the RI/FS cores are reevaluated using data only from 

portion of the curve that decreases with increasing mass 

accumulation (RI/FS data points with symbols in fig. B1), 

the two data sets yield comparable sedimentation rates. 

Additionally, the smaller sedimentation rate calculated for 

ENVVEST core S3 is consistent with the time markers of

137Cs data, whereas the larger sedimentation rates originally 

calculated by the RI/FS were not consistent with time markers 

of the 137Cs data in the cores from locations 475 and 490. In 

addition, the mercury and lead data from the same ENVVEST 

cores and the assumption of the impact of the 1895 opening 

of the PSNS also are generally consistent with the lower 

estimated sedimentation rate.

In this study, the physical characteristics of sediment 

samples from the 500-ft and 1,500-ft LTMP grids were used to 

scale up the few sedimentation rates derived from ENVVEST 

project core data to the entire Sinclair Inlet study area. The 

following procedures were followed:
Appendix B 85

1. Zero sedimentation was assumed between mean lower 

low water (MLLW) and 5 m below MLLW. 

2. The area below 5-m MLLW of the each 500-ft grid 

was calculated.

3. The area below 5-m MLLW of each 500-ft grid was 

assigned a sedimentation based on the average percentage 

of fines from the 2003, 2005 and 2007 LTMP.

. a. Grid cells with less than 50 percent fines were assigned 

a zero sedimentation rate.

b. Grid cells with percentage fines between 50 percent and 

85 percent were assigned a sedimentation rate of 0.09 g 

cm-2 yr-1 (average of S1 and S5 cores).

c. Grid cells with percentage fines greater than 

85 percent were assigned a sedimentation rate of 

0.14 g cm-2 yr-1 (median of cores S2–S3). 

4. Areas adjacent to the shoreline greater than 5-m MLLW, 

which were not covered by a 500-ft grid, were assigned 

a sedimentation rate based on the average of adjacent 

grid cells.

5. At the interface between the 500-ft grid and 1,500-ft grid, 

the area of 1,500-ft that was overlapped by a 500-ft grid 

was subtracted from the area of the 1,500-ft grid.

6. Areas at the interface between the 500-ft grid and 

1,500-ft grid, which were not covered by either grid, were 

identified and assigned a sedimentation rate based on the 

percentage fines of adjacent 500-ft and 1,500-ft grids. 

7. Areas adjacent to the shoreline shallower than 5-m 

MLLW, which were outside of the 500-ft grid and not 

covered by a 1,500-ft, were assigned a sedimentation rate 

based upon percentage fines of adjacent 1,500-ft grids.

8. All areas below 5-m MLLW and outside of the 500-ft 

grid are assigned a sedimentation rate based upon 

procedure. The area at the seaward boundary of the 

study areas, which were not covered by the 1,500-ft 

grid, were assigned a zero sedimentation rate because 

the median percentage of fines of the four grid cells is 

42 percent fines. 

9. The mass accumulation of all 500-ft grids, 1,500-ft 

grids, and areas outside of the both grids and adjacent 

to shorelines are summed to calculate a total mass 

sedimentation of Sinclair Inlet. 

When the sedimentation rates assigned are applied to 

cells from the cells described above, an annual sedimentation 

of 7,120 metric tons of sediments (dry weight) is estimated 

over a depositional area of 6.23 km2 (table B1). This compares 

to the ENVVEST estimate of 10,778 metric tons over an 

area of 7.9 km2. Thus, it appears that the main difference 

between the approach described above and the ENVVEST 

approach, which average over different length scales, is that 

the depositional area in this study is smaller because of the 

exclusion of an area of coarse-grained sediments. 

If shoreline areas within the BNC that were not covered 

by the 500-ft grid were added to the 500-ft BNC grid, annual 

sedimentation of 1,600 metric tons of sediment within the 

BNC is calculated. In contrast, 5,570 metric tons of sediments 

were annually deposited in greater Sinclair Inlet. 

References Cited

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., USA: American Chemical Society, p. 

365–389.

Crecelius, E.A., Robert, K., Johnston, R.K., Leather, J., 

Guerrero, J., Mille, M., and Brandenberger, J., 2003, 

Contaminant mass balance for Sinclair and Dyes Inlets, 

Puget Sound, Washington, in Georgia Basin Puget 

Sound Research Conference, Vancouver, B.C., Canada, 

April 2, 2003, Proceedings: Olympia, Wash., Puget 

Sound Partnership, accessed April 2, 2012, at http://

www.pugetsoundinstitute.org/archives/conf/2003GBPS_

ResearchConference/SESSIONS/SESS_6E.htm. 

Paulson, A.J., Keys, M., and Scholting, K., 2010, Mercury 

in the Sediments, Waters and Biota of Sinclair Inlet, Puget 

Sound, Washington (1999–2007): U.S. Geological Survey 

Open-File Report 2009-1285, 220 p. 

U.S. Navy, 2002, Final Remedial Investigation Report 

Operable Unit B, Bremerton Naval Complex, Bremerton, 

Washington: Final Report prepared by the URS Grier under 

contract #N62474-89-0-9295, Volume 1, 1,402 p.
86 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table B1. Concentrations of carbon, and percent fines in sediment samples and assumed sedimentation rates from cells in Sinclair 

Inlet, Kitsap County, Washington, 2003–07.

[Values of mercury and assumed sedimentation in shore and interface cells are estimated from an average of adjacent cells. Cell type: GSI grid cells shown in 

figure 2; BNC grid cells shown in figure 3. Shore cells are unaccounted area along the shore that are between two grid cells. Interface cells are unaccounted area 

between BNC and GSI grid cells. Fines: Fraction of sediment less than 0.625 micrometer. Abbreviations: GSI, greater Sinclair Inlet; BNC, Bremerton naval 

complex; m2, square meter; (g cm-2 yr-1, gram per square centimeter per year]

Cell type Cell No. or 

description

Total organic carbon

(percentage by weight)

Fines

(percentage by weight) Area of cell

(m2

)

Assumed 

sedimentation 

rate

[g cm-2 yr-1]

Annual 

sedimentation 

in cell

(metric tons 

per year) Average Standard

deviation Average Standarddeviation

Cells in greater Sinclair Inlet

Grid 01 1.8 0.4 48 17 0 0 0

Grid 02 0.9 0.0 39 2 0 0 0

Grid 03 1.4 0.3 26 3 0 0 0

Grid 04 0.9 0.3 21 5 0 0 0

Grid 05 3.3 0.5 69 4 101,318 0.09 91

Grid 06 3.9 0.3 90 5 174,311 0.14 244

Grid 07 4.2 0.1 92 5 138,623 0.14 194

Grid 08 3.6 0.3 95 2 143,023 0.14 200

Grid 09 3.9 0.1 90 6 201,301 0.14 282

Grid 10 3.5 0.2 97 2 198,928 0.14 278

Grid 11 3.5 0.1 90 2 20,794 0.14 290

Grid 12 0.9 0.1 20 1 33,799 0 0

Grid 13 3.1 0.1 93 2 182,999 0.14 256

Grid 14 3.7 0.2 91 6 206,740 0.14 289

Grid 15 3.8 0.4 94 6 180,438 0.14 253

Grid 16 4.0 0.3 91 5 91,421 0.14 128

Grid 17 3.2 0.3 92 4 209,002 0.14 293

Grid 18 3.3 0.1 91 5 209,025 0.14 293

Grid 19 3.4 0.4 92 7 202,098 0.14 283

Grid 20 3.0 0.2 90 4 154,163 0.14 216

Grid 21 3.1 0.4 89 5 209,025 0.14 293

Grid 22 3.0 0.3 91 3 209,025 0.14 293

Grid 23 2.7 0.4 65 2 125,609 0.09 113

Grid 24 2.8 0.1 82 2 206,465 0.09 186

Grid 25 2.0 0.6 54 3 183,751 0.09 165

Grid 26 0.4 0.1 12 1 6,551 0 0

Grid 27 3.1 0.3 83 2 141,096 0.09 127

Grid 28 2.9 0.4 79 4 209,025 0.09 188

Grid 29 1.7 0.2 50 2 164,505 0.09 148

Grid 30 0.4 0.0 13 4 18,236 0 0

Grid 31 2.5 0.1 80 3 192,210 0.09 173

Grid 32 1.3 0.2 36 4 133,693 0 0

Shore Between GSI cells 5 and 7 11,406 0.14 16

Shore NW of GSI cells 5 and 6 22,967 0.09 21

Shore Between GSI cells 19 and 23 12,523 0.09 11

Interface NE of GSI cell 10 and SW of OU B Marine cells 1 and 2

NW of GSI cell 13 and between OU B Marine cells 2 and 5

19,330 0.14 27

Interface 22,378 0.14 31

Interface Between GSI cells 13 and 17 15,917 0.14 22

Interface NW of GSI cells 17 and 20, and SE of OU B Marine cells 13, 17 and 20 10,155 0.14 14

Interface Between GSI cells 21 and 24, and SW of OU B Marine cells 37 and 38 78,255 0.14 110

Interface NW of GSI cell 24 and between OU B Marine 28 and 44 16,920 0.09 15

Interface Between GIS cells 27 and 31, and between OU B Marine cells 54 and 58 19,823 0.09 18

Interface NW of GSI cell 31 and between OU B marine cells 58 and 62 6,135 0.09 6

GSI Total 4.67 5,570
Appendix B 87

Cell type Cell No. or 

description

Total organic carbon

(percentage by weight)

Fines

(percentage by weight) Area of cell

(m2

)

Assumed 

sedimentation 

rate

[g cm-2 yr-1]

Annual 

sedimentation 

in cell

(metric tons 

per year) Average Standard

deviation Average Standarddeviation

Cells within OU B Marine

Grid 01 3.1 0.3 60 14 23,216 0.09 20.89

Grid 02 3.3 0.2 93 5 23,225 0.14 32.51

Grid 03 1.7 0.1 44 6 13,896 0 0

Grid 04 3.0 0.3 91 9 23,225 0.14 32.52

Grid 05 2.8 0.1 88 6 23,225 0.14 32.51

Grid 06 2.7 0.2 87 5 17,675 0.14 24.74

Grid 07 2.7 0.2 90 5 23,225 0.14 32.51

Grid 08 2.5 0.1 88 3 23,225 0.14 32.51

Grid 09 2.6 0.1 91 1 23,225 0.14 32.51

Grid 10 1.4 0.3 52 7 22,528 0.09 20.27

Grid 11 2.3 0.1 87 3 23,225 0.14 32.52

Grid 12 2.6 0.4 90 0 23,225 0.14 32.51

Grid 13 2.9 0.2 88 6 23,224 0.14 32.51

Grid 14 1.0 0.3 32 5 7,767 0 0

Grid 15 2.2 0.0 88 2 21,240 0.14 29.74

Grid 16 2.5 0.2 90 2 23,225 0.14 32.52

Grid 17 2.7 0.1 92 4 23,225 0.14 32.51

Grid 18 1.6 0.8 42 5 12,435 0 0

Grid 19 2.3 0.2 81 5 23,225 0.09 20.9

Grid 20 2.7 0.2 93 1 23,225 0.14 32.51

Grid 21 1.8 0.2 68 5 22,576 0.09 20.32

Grid 22 3.0 0.2 97 2 23,225 0.14 32.51

Grid 23 2.9 0.2 90 5 23,225 0.14 32.51

Grid 24 3.1 0.4 88 4 13,106 0.14 18.35

Grid 25 3.0 0.3 85 6 23,225 0.14 32.51

Grid 26 3.2 0.4 83 11 23,225 0.09 20.9

Grid 27 3.3 0.4 85 3 23,225 0.14 32.51

Grid 28 2.3 0.6 71 13 22,111 0.09 19.9

Grid 29 3.5 0.1 83 11 23,225 0.09 20.9

Grid 30 3.0 0.1 86 1 23,225 0.14 32.52

Grid 31 2.9 0.1 93 1 23,225 0.14 32.52

Grid 32 2.7 0.1 93 2 23,225 0.14 32.52

Grid 33 3.2 0.3 88 2 16,225 0.14 22.72

Grid 34 2.6 0.3 72 15 23,225 0.09 20.9

Grid 35 2.5 0.3 76 3 23,225 0.09 20.9

Grid 36 3.0 0.1 88 3 23,225 0.14 32.52

Grid 37 3.0 0.3 87 2 23,124 0.14 32.37

Grid 38 2.2 0.1 69 3 23,225 0.09 20.9

Grid 39 2.1 0.8 37 6 10,331 0 0

Grid 40 2.7 0.3 73 5 22,921 0.09 20.63

Grid 41 3.1 0.6 74 10 20,728 0.09 18.66

Grid 42 2.7 0.1 79 3 21,315 0.09 19.18

Grid 43 2.9 0.5 72 6 15,329 0.09 13.7

Grid 44 2.9 0.1 90 4 23,225 0.14 32.51

Grid 45 3.0 0.7 66 22 18,044 0.09 16.24

Table B1. Concentrations of carbon, and percent fines in sediment samples and assumed sedimentation rates from cells in Sinclair 

Inlet, Kitsap County, Washington, 2003–07.—Continued

[Values of mercury and assumed sedimentation in shore and interface cells are estimated from an average of adjacent cells. Cell type: GSI grid cells shown in 

figure 2; BNC grid cells shown in figure 3. Shore cells are unaccounted area along the shore that are between two grid cells. Interface cells are unaccounted area 

between BNC and GSI grid cells. Fines: Fraction of sediment less than 0.625 micrometer. Abbreviations: GSI, greater Sinclair Inlet; BNC, Bremerton naval 

complex; m2, square meter; (g cm-2 yr-1, gram per square centimeter per year]
88 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Cell type Cell No. or 

description

Total organic carbon

(percentage by weight)

Fines

(percentage by weight) Area of cell

(m2

)

Assumed 

sedimentation 

rate

[g cm-2 yr-1]

Annual 

sedimentation 

in cell

(metric tons 

per year) Average Standard

deviation Average Standarddeviation

Cells within OU B Marine—Continued

Grid 46 1.5 0.5 30 3 22,694 0 0

Grid 47 2.4 0.2 80 3 23,225 0.09 20.9

Grid 48 3.1 0.1 92 3 23,225 0.14 32.51

Grid 49 1.9 0.6 58 20 17,837 0.09 16.05

Grid 50 2.7 0.1 85 3 23,225 0.09 20.9

Grid 51 3.1 0.2 89 9 23,225 0.14 32.51

Grid 52 2.8 0.4 83 9 22,043 0.09 19.84

Grid 53 2.6 0.1 83 3 23,225 0.09 20.9

Grid 54 3.4 0.4 82 2 23,225 0.09 20.9

Grid 55 3.3 1.2 62 13 21,425 0.09 19.28

Grid 56 3.4 0.7 78 6 23,225 0.09 20.9

Grid 57 3.9 1.1 80 10 23,225 0.09 20.9

Grid 58 3.0 0.1 85 2 23,225 0.09 20.9

Grid 59 3.3 0.6 77 2 23,225 0.09 20.9

Grid 60 2.7 0.4 51 3 23,225 0.09 20.9

Grid 61 1.9 0.3 36 4 23,225 0.09 20.9

Grid 62 3.0 0.1 83 3 23,225 0.09 20.9

Grid 63 3.6 1.3 62 8 14,636 0.09 13.17

Grid 64 3.5 0.1 81 4 23,225 0.09 20.9

Grid 65 2.6 0.2 67 12 22,470 0.09 20.22

Grid 66 3.3 0.3 81 7 22,172 0.09 19.95

Grid 67 3.3 1.2 52 9 13,450 0.09 12.1

Grid 68 2.9 0.1 72 12 12,290 0.09 11.06

Grid 69 2.2 0.4 36 3 15,741 0 0

Grid 70 2.7 0.1 78 7 23,225 0.09 20.9

Grid 71 0.8 0.1 18 2 21,153 0 0

Interface SW of OU B Marine cells 31 and 32 and NE of GSI cells 20 and 21 2,992 0.14 4.19

Interface SW of OU B Marine 58 and W of GSI cell 31 4,898 0.09 4.41

Shore Between OU B Marine cells 6 and 10 5,212 0.09 4.69

Shore Between OU B Marine cells 24 and 28 5,681 0.09 5.11

Shore Between OU B Marine cells 28 and 33 1,994 0.09 1.79

Shore NE of OU B Marine cells 40 and 41 8,768 0.09 7.89

Shore Between OU B Marine cells 37 and 42 6,835 0.09 6.15

Shore NW of OU B Marine cells 59 and 63 11,944 0.09 10.75

BNC total 1.56 1,620

Sinclair Inlet total 6.23 7,190

Table B1. Concentrations of carbon, and percent fines in sediment samples and assumed sedimentation rates from cells in Sinclair 

Inlet, Kitsap County, Washington, 2003–07.—Continued

[Values of mercury and assumed sedimentation in shore and interface cells are estimated from an average of adjacent cells. Cell type: GSI grid cells shown in 

figure 2; BNC grid cells shown in figure 3. Shore cells are unaccounted area along the shore that are between two grid cells. Interface cells are unaccounted area 

between BNC and GSI grid cells. Fines: Fraction of sediment less than 0.625 micrometer. Abbreviations: GSI, greater Sinclair Inlet; BNC, Bremerton naval 

complex; m2, square meter; (g cm-2 yr-1, gram per square centimeter per year]
Appendix C 89

Appendix C. Calculation of Total Mercury Concentrations of Solids

USGS data are compared 

(table C1) to U.S. Navy groundwater 

data and ENVVEST data for creeks, 

stormwater drains, and marine water 

using equation 1 to evaluate the 

representativeness of USGS samples.

The THg concentration of solids 

(ng/mg = mg/kg) collected from a 

terrestrial site (tables C2 and C3) or 

marine station (table C4) is obtained 

by dividing the concentration of PTHg 

(ng/L) obtained by filtering particles 

onto a QFF by the concentration of 

TSS (mg/L) obtained by filtering 

particles onto a polycarbonate filter 

(Huffman and others, 2012) according 

to equation 2. From December 2007 

through September 2008, the water 

filtered through these two filters was 

taken from different bottles collected 

during the sequential filling of bottles 

at a site. If the TSS concentration 

in the water being sampled changed 

substantially during the sequential 

filling of bottles before October 2008, 

the calculation of THg of solids are 

biased. Beginning in October 2008, 

paired sets of solids for PTHg and 

TSS measurements were taken from 

the same bottle sampled at a site. 

Because of the possibility of sampling 

bias by sequential sampling during 

changing TSS conditions in 2008, 

PTHg concentrations associated with 

TSS concentrations less than 0.5 mg/L 

taken from a different bottle than the 

PTHg sample are disregarded in the 

statistical analyses.

Table C1. Comparisons of the sum of filtered and particulate total mercury 

concentrations with total mercury concentrations from whole water for comparable 

samples.

[Abbreviations: PTHg, particulate total mercury; FTHg, filtered total mercury; WTHg, whole water total 

mercury; ng/L, nanograms per liter; –, not available; <, less than]

Field identifer PTHg + FTHg 

(ng/L)

WTHg

(ng/L)

FTHg 

(ng/L) 

Groundwater

USGS LTMP

USGS LTMP

OUBT-722, pre-2008 – 980–6,690 – 210–970

OUBT-722, 2008-2009 500–2,124 1,190–3,690 453–1,970 –

OUBT-724, pre-2008 – <200–5,240 – <200

OUBT-724, 2008-2009 <10, 7.5 27.5–41.6 <10, 6.52 –

Creeks during dry baseflow

USGS ENVVEST

Gorst Creek 0.53–1.16 2.89–4.01

Anderson Creek 0.75–1.50 1.2

Blackjack Creek 0.93–0.98 1.06–1.39

Annapolis Creek 0.78–1.20 1.13

Olney Creek 1.19–1.89 1.72

Stormwater drains during storms

USGS ENVVEST

PSNS015 366 15–1,131

PSNS124 19.1 17.2–44.0

NAVY CITY 38.95 14.1–56.1

Upper layer marine water—Greater Sinclair Inlet

USGS ENVVEST

Number of samples 29 17

Mean 0.89 1.09

Median 0.75 0.97

Minimum 0.45 0.72

Maximum 2.52 8.44

Upper layer marine water—OU B Marine

USGS ENVVEST

Number of samples 23 10

Mean 0.84 2.36

Median 0.31 1.52

Minimum 0.02 0.78

Maximum 11.91 10.71

1

PTHg not measured. Assumed a value of 0.5 ng/L, medium value for layer. 
90 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table C2. Calculations of total mercury of solids discharging to greater Sinclair Inlet, Kitsap County, Washington, 

December 2007–January 2009.

[Values in bold are average of field replicate samples. Abbreviations: ng/L, nanogram per liter; mg/L, milligram per liter; THg, total mercury; 

ng/mg, nanogram per milligram and is same unit as mg/kg, milligram per kilogram; WWTP, wastewater treatment plant]

Field identifier Date Time

Particulate 

total mercury 

(ng/L)

Total 

suspended 

solids 

(mg/L)

THg of 

suspended 

solids 

(mg/kg)

Wastewater treatment plant

Bremerton WWTP 05-08-08 0625 0.757 3.6 0.210

07-15-08 0650 0.474 2.59 0.183

08-14-08 0630 1.68 8.38 0.200

Stormwater 

Storm outfall at Sheridan Road near Bremerton 01-08-09 1720 1.83 11.65 0.157

Stormwater outfall at Port Orchard boat ramp 01-08-09 1840 2.85 20.63 0.138

Drainage outfall at Navy City near Gorst 01-07-09 2120 34.7 362.8 0.096

Streams

Gorst Creek 05-09-08 1130 0.135 1.52 0.089

07-14-08 0900 0.347 58.8 10.006

Anderson Creel 05-08-08 1140 0.176 2.75 0.064

07-15-08 1200 0.926 3.85 0.240

Blackjack Creek 05-07-08 1440 0.258 2.38 0.108

07-14-08 1100 0.413 3.24 0.127

Annapolis Creek 05-09-08 1330 0.481 1.91 0.251

07-15-08 0950 0.268 0.95 0.283

Olney Creek 05-08-08 1400 0.763 6.50 0.117

07-14-08 1310 1.46 9.14 0.160

1Considered outlier.
Appendix C 91

Table C3. Calculations of total mercury of solids discharging to OU B Marine, 

Bremerton naval complex, Kitsap County, Washington, December 2007–March 2010.

[Values in bold are average of field replicate samples. Abbreviations: THg, total mercury; OUBT, 

Operable Unit B Terrestrial; OU NSC; Operable Unit Naval Supply Center; PSNS, Puget Sound Naval 

Shipyard; ng/L, nanogram per liter; mg/L, milligram per liter; ng/mg, nanogram per milligram and is 

same unit as mg/kg, milligram per kilogram]

Field 

identifier Date Time

Particulate 

total 

mercury 

(ng/L)

Total 

suspended 

solids 

(mg/L)

THg of 

suspended 

soids

(mg/kg)

Dry dock drainage relief systems

Dry Dock 1–5, pump 4 12-12-07 1115 6.53 0.49 213.2

12-12-07 11245 2.79 0.74 3.75

02-19-08 1030 2.60 0.74 3.52

Dry Dock 1–5, pump 5 01-29-08 1050 3.80 0.84 4.54

03-26-08 1100 3.06 1.31 2.34

04-23-08 1230 2.07 0.64 3.23

05-28-08 1050 2.12 1.47 1.45

06-24-08 1030 57.4 43.62 1.32

Dry Dock 6 02-19-08 11600 4.38 0.85 5.17

02-19-08 1630 2.03 0.58 3.49

03-26-08 1300 2.57 0.29 28.74

04-25-08 1340 2.90 0.16 217.7

05-28-08 1200 1.94 1.43 1.36

06-24-08 1120 1.75 1.37 1.27

Steam plant effluent

Steam Plant 03-26-08 1400 59.4 1.45 40.9

04-25-08 1030 32.5 0.47 68.72

05-28-08 1350 23.85 1.39 17.1

06-24-08 1220 2.16 0.73 2.95

Groundwater in Operating Units B and NSC 

captured by the dry dock drainage relief systems

OUBT-406R 01-31-08 1500 0.549 0.58 0.94

OUBT-406R 04-23-08 1500 <0.057 0.56 <0.101

OUBT-709 01-30-08 1550 8.39 0.18 46.82

OUBT-709 04-24-08 1530 3.57 1.13 3.15

OUBT-724 02-01-08 1030 1.79 1.00 1.78

OUBT-724 04-24-08 1200 0.925 2.20 0.42

OUNSC-380 01-30-08 1310 0.583 0.43 1.35

OUNSC-380 04-22-08 1030 0.667 0.55 1.22

Stormwater 

PSNS124.1 01-07-09 1720 32.7 158 0.21

PSNS124 01-07-09 1830 17.6 35.53 0.495

PSNS015 01-07-09 2010 222 151.8 1.46

Tidal flushing of PSNS 015 storm drain

PSNS015-2253 12-29-09 1340–2000 21.89 1.35 16.2

PSNS015-2253 03-31-10 1010–1400 54.57 2.86 19.1

1Composite sample, previous 24 hours.

2Total suspended solids concentrations less than 0.5 mg/L and taken from a different bottle than 

the PTHg sample. May be affected by temporal alaising and disregarded in statistical applications and 

plots.
92 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

Table C4. Calculations of total mercury of solids collected in the marine waters of Sinclair Inlet, 

Kitsap County, Washington, August 2008–August 2009.

[Values in bold are the average from two different bottles. Abbreviations: ng/L, nanogram per liter; mg/L, milligram 

per liter; THg, total mercury; ng/mg, nanogram per milligram and is same unit as mg/kg, milligram per kilogram; –, not 

analyzed]

Field identifier Date Time

Particulate 

total 

mercury 

(ng/L)

Total

suspended 

solids

(mg/L)

THg of 

suspended 

solids 

(mg/kg)

Bremerton naval complex lower layer

BNC-39-BOT 08-18-08 1110 4.13 4.03 1.025

BNC-39-BOT 02-06-09 1100 0.745 1.22 0.611

BNC-39-BOT 06-05-09 1000 1.7 2.8 0.607

BNC-39-BOT 08-07-09 0900 5.59 6.58 0.849

BNC-52-BOT 08-15-08 0930 0.392 1.13 0.347

BNC-60-BOT 02-04-09 1300 0.634 1.73 0.366

BNC-60-BOT 06-03-09 0930 1.21 2.82 0.429

BNC-60-BOT 08-05-09 0900 0.641 1.07 0.599

BNC-71-BOT 08-18-08 1240 0.767 101.2 0.008

BNC-71-BOT 02-06-09 1300 0.281 6.25 0.045

BNC-71-BOT 06-05-09 1200 0.717 2.27 0.316

BNC-71-BOT 08-07-09 1300 1.02 1.97 0.517

Bremerton naval complex upper layer

BNC-39-SURF 02-06-09 1130 0.401 0.71 0.565

BNC-39-SURF 06-05-09 1000 0.422 2.26 0.187

BNC-39-SURF 06-05-09 1001 0.452 2.72 0.166

BNC-39-SURF 08-07-09 0900 0.672 3.42 0.196

BNC-39-SURF 08-18-08 1020 0.629 2.01 0.313

BNC-52-SURF 08-15-08 1110 0.264 2.16 0.122

BNC-52-SURF 09-19-08 1240 0.566 4.35 0.130

BNC-52-SURF 10-22-08 1130 0.456 1.09 0.418

BNC-52-SURF 11-18-08 1200 0.528 1.21 0.436

BNC-52-SURF 02-04-09 1130 0.302 2.59 0.117

BNC-52-SURF 03-18-09 1230 0.283 0.92 0.308

BNC-52-SURF 04-08-09 1100 0.435 2.99 0.145

BNC-52-SURF 05-07-09 1100 0.522 1.69 0.308

BNC-52-SURF 06-03-09 1100 0.165 2.02 0.082

BNC-52-SURF 07-08-09 1130 0.175 2.45 0.071

BNC-52-SURF (set 1) 08-05-09 1030 0.517 4.24 0.122

BNC-52-SURF (set 1) 08-05-09 1032 0.667 6.45 0.103

BNC-71-SURF 08-18-08 0940 0.38 0.97 0.392

BNC-71-SURF 02-06-09 1330 0.216 0.73 0.296

BNC-71-SURF 06-05-09 1230 0.573 3.15 0.182

BNC-71-SURF 08-07-09 1300 0.513 3.22 0.159

Convergence zone

CZ-BOT 02-05-09 1230 0.462 1.84 0.251

CZ-SURF 08-14-08 1240 0.303 2.56 0.118

CZ-SURF 09-19-08 1140 0.443 1.9 0.233

CZ-SURF 10-22-08 1050 0.502 1.06 0.474

CZ-SURF 11-18-08 1110 0.586 1.2 0.488

CZ-SURF 02-02-09 1130 0.339 0.76 0.446

CZ-SURF 03-17-09 1100 0.427 1.45 0.294

CZ-SURF 04-07-09 1100 0.742 2.44 0.304

CZ-SURF 05-06-09 1100 0.587 2.15 0.273

CZ-SURF 06-01-09 1100 0.527 2.88 0.183

CZ-SURF 07-07-09 1130 0.394 1.95 0.203

CZ-SURF 08-03-09 1130 0.482 2.34 0.206
Appendix C 93

Field identifier Date Time

Particulate 

total 

mercury 

(ng/L)

Total

suspended 

solids

(mg/L)

THg of 

suspended 

solids 

(mg/kg)

Greater Sinclair Inlet lower layer

SI-IN-BOT 08-15-08 1400 0.633 1.26 0.502

SI-IN-BOT 02-04-09 1430 0.416 0.96 0.433

SI-IN-BOT 06-03-09 1330 0.791 2.2 0.360

SI-IN-BOT 08-05-09 1230 1.4 3.42 0.409

SI-OUT-BOT 08-14-08 1000 1.79 3.71 0.482

SI-OUT-BOT 02-02-09 1400 0.821 1.95 0.421

SI-OUT-BOT 06-01-09 1400 0.634 2.58 0.246

SI-OUT-BOT 08-03-09 1230 0.184 2.12 0.087

SI-PO-BOT 08-14-08 1400 0.291 2.18 0.133

SI-PO-BOT 02-02-09 0950 0.845 1.93 0.438

SI-PO-BOT 06-01-09 0900 1.94 3.42 0.567

SI-PO-BOT 08-03-09 0930 0.478 1.29 0.372

Greater Sinclair Inlet upper layer

SI-IN-SURF 08-15-08 1200 0.475 3.98 0.119

SI-IN-SURF 09-18-08 1120 0.785 10.25 0.077

SI-IN-SURF 10-21-08 1100 0.718 7.22 0.100

SI-IN-SURF 04-08-09 1150 0.434 2.14 0.203

SI-IN-SURF 05-07-09 1200 0.826 2.19 0.376

SI-IN-SURF 06-03-09 1130 0.153 2.13 0.072

SI-IN-SURF 07-08-09 1100 0.196 1.85 0.106

SI-IN-SURF 08-05-09 1200 1.79 10.68 0.168

SI-IN-SURF 11-17-08 1120 0.477 1.3 0.367

SI-IN-SURF 02-04-09 1040 0.399 0.98 0.407

SI-IN-SURF 03-18-09 1130 0.34 1.44 0.236

SI-OUT-SURF 02-02-09 1420 0.328 0.78 0.421

SI-OUT-SURF 06-01-09 1330 0.239 2.62 0.091

SI-OUT-SURF 08-03-09 1230 0.572 4.11 0.139

SI-OUT-SURF 08-14-08 1140 0.346 3.78 0.092

SI-OUT-SURF 08-14-08 1150 0.25 – 0.066

SI-PO-SURF 09-18-08 1240 0.489 4.99 0.098

SI-PO-SURF 09-18-08 1241 0.625 – 0.125

SI-PO-SURF 10-21-08 1205 0.438 0.93 0.471

SI-PO-SURF 11-17-08 1150 0.574 1 0.574

SI-PO-SURF 02-02-09 1050 0.317 0.44 0.720

SI-PO-SURF 03-17-09 1200 0.403 1.37 0.294

SI-PO-SURF 04-07-09 1200 0.453 2.61 0.174

SI-PO-SURF 05-06-09 1200 0.309 1.45 0.214

SI-PO-SURF 06-01-09 1200 0.372 2.7 0.138

S-PO-SURF 07-07-09 1200 0.357 2.74 0.130

S-PO-SURF 08-03-09 1040 0.33 2.62 0.126

Table C4. Calculations of total mercury of solids collected in the marine waters of Sinclair Inlet, 

Kitsap County, Washington, August 2008–August 2009.—Continued

[Values in bold are the average from two different bottles. Abbreviations: ng/L, nanogram per liter; mg/L, milligram 

per liter; THg, total mercury; ng/mg, nanogram per milligram and is same unit as mg/kg, milligram per kilogram; –, not 

analyzed]
94 Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10

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Paulson and others— Sources and Sinks of Filtered Total Mercury and Solids, and Filtered Methylmercury, Sinclair Inlet, Washington, 2007–10—SIR 2012–5223