United States
Environmental Protection
Agency
EPA 910-R-12-001 I www.epa.gov
February 2012
Assessment of Mercury in Fish
Tissue from Select Lakes of
Northeastern Oregon
EPA Region 10 Report
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Assessment of Mercury in Fish Tissue from Select Lakes of
Northeastern Oregon
EPA Region 10 Report
Authors:
Lillian Merger and Lorraine Edmond
February 2012
U.S. Environmental Protection Agency, Region 10
Office of Environmental Assessment
1200 Sixth Avenue, Suite 900
Seattle, Washington 98101
Publication Number: EPA 910-R-12-001
Suggested Citation:
Merger, L.G. and L. Edmond. 2012. Assessment of mercury in fish tissue from selected
lakes in northeastern Oregon, EPA Region 10 Report. Report Number EPA-910-R-12-
001. U.S. Environmental Protection Agency, Region 10, Seattle, Washington.
This document is available at:
http://www.epa.gov/region10/pdf/publications/reports/hg_in_fish_tissue_ne_or_feb2012.pdf
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Northeast Oregon Lakes Mercury
List of Figures ii
List of Tables ii
List of Maps ii
List of Appendices ii
Acknowledgements iii
Abstract iii
Introduction 1
Study Area and Waterbody Selection 2
Target Species and Sample Hierarchy 4
Methods 6
Field Methods 6
Laboratory Fish Processing Methods 6
Data Summary Methods 7
Results 7
Sampling Results 7
Analysis Results 8
Discussion 9
A. Thresholds for evaluating need for fish advisories 9
B. Relevance to Fish Advisories 10
Phillips Reservoir 10
Powder Arm of Brownlee Reservoir 10
C. Comparison with regional studies 11
Conclusions 14
References 15
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Northeast Oregon Lakes Mercury
List of Figures
Figure 1. Hierarchy for fish advisory for NE Oregon lake fish tissue study used to guide
fish collection 5
Figure 2. Fish tissue processing: tissue excision and blending composited tissue 7
Figure 3. Graph of mercury concentration in fish species by water body. Where
replicate samples were collected, data are presented as mean values as shown on
Table 1. Purple line indicates current advisory threshold of 0.23 mg/kg used by OHA....9
Figure 4. Comparison of NE Oregon fish tissue mercury concentration means and
medians to results from other studies (sources: Essig and Kosterman 2008, Merger et
al. 2011, Johnson etal. 2011) 13
Table 1. Location and description of sample reservoirs 2
Table 2. Northeast Oregon fish sampling results 8
Table 3. Data collected from Phillips Reservoir on September 27, 1994 from the
deepest part of the lake (unpublished data provided by OHA) 10
Table 4. Summary of fish tissue mercury concentrations from other studies in the area
compared to the NE Oregon results (units in mg/kg wet weight) 12
Map 1. Northeastern Oregon Mercury Project Area showing model-predicted mercury
deposition 3
List of Appendices
Appendix 1. List of lakes considered for sampling in northeastern Oregon A
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Northeast Oregon Lakes Mercury
Acknowledgem ents
This project was initiated by Christine Kelly and Leigh Woodruff (USEPA), who brought
to our attention the need for mercury fish tissue data from this area. Christine led the
interagency workgroup, comprised of USEPA, ODEQ, ODFW, and OHA, who helped
define the scope of the project. Linda Hayes-Gorman, John Dadoly, and Agnes Lut
(ODEQ) helped prioritize waterbodies. Barbara Stifel and Curtis Cude (OHA) provided
direction on data usefulness for fish consumption advisories. Tim Bailey, Nadine Craft,
Ray Perkins, and Terry Schrader (ODFW) provided local insight on waterbodies and
fish species availability.
ODFW also provided field assistance and gear for fish collection at four of the sample
lakes. We thank ODFW fish biologists Nadine Craft and Ray Perkins for their help.
Idaho Power Company provided gear and assistance for collections on the Powder
River Arm of Brownlee Reservoir. We thank Idaho Power biologist Tracy Richter for her
assistance. Ken Lujan (USFWS), Leigh Woodruff (USEPA) and Michael McLeod and
John Anderson (Idaho Power) also helped with fish collection. Jennifer Crawford and
Don Matheny (USEPA) assisted with laboratory sample preparation and provided
quality assurance technical support. Lon Kissinger (USEPA) provided technical review
for human health aspects of the report. Helen Rueda (USEPA) compiled past mercury
monitoring data.
Abstract
A fish tissue study was conducted in five northeastern Oregon reservoirs to evaluate
mercury concentrations in an area where elevated atmospheric mercury deposition had
been predicted by a national EPA model, but where tissue data were sparse. The study
targeted resident predator species that are known to be caught and consumed by
humans. The study design was based on EPA guidance and intended to be adequate
for use by state authorities who develop consumption advisories where needed.
A total of 19 composite samples of muscle tissue were collected and analyzed from
Balm Creek, Bully Creek, Phillips, Thief Valley, and Powder River Arm of Brownlee
reservoirs. An adequate number of samples useable for fish advisory evaluation was
collected for at least one species at four of the five reservoirs. Mean total mercury
concentration ranged from a low of 0.06 mg/kg in rainbow trout of Thief Valley Reservoir
to a high of 0.58 mg/kg in yellow perch of Phillips Reservoir.
Data are compared to threshold values used by Oregon Department of Health for fish
advisory screening. Based on these 2011 sample results, Phillips Reservoir is a
candidate for development of a fish advisory for consumption of yellow perch. The
mean of two samples was 0.58 mg/kg, substantially higher than the 0.23 mg/kg
threshold used by Oregon Health Authority. These results confirm previous data
collected from Phillips Reservoir. An advisory for sport fish has been in effect for
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Northeast Oregon Lakes Mercury
Brownlee Reservoir since 1997. The 2011 results from the Powder River Arm of
Brownlee Reservoir are similar to what has been found in past data.
The Northeast Oregon results are compared to results from large scale studies
conducted elsewhere in the Pacific Northwest. Data gaps that would be useful to fill if
resources become available include sampling of the remaining game species in all five
reservoirs, and sampling fish species for mercury concentrations in other nearby
reservoirs.
IV
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Northeast Oregon Lakes Mercury
Introduction
Exposures to mercury can affect the human nervous system and harm the brain, heart,
kidneys, lungs, and immune system. The most common way people are exposed to
mercury is by eating fish or shellfish that are contaminated with mercury. Results from
a recent EPA national modeling effort, REMSAD (REgional Modeling System for
Aerosols and Deposition), predicted a significant mercury deposition area in
northeastern Oregon (ICF Consulting Inc. 2008). Currently, there is a general lack of
fish tissue data from lakes and streams in this area. Given the potentially elevated level
of mercury deposition and lack of fish tissue data, there is a need to measure mercury
concentrations in fish to determine if there is a health risk.
To ensure the continued good health of its citizens, the State of Oregon issues fish
consumption advisories for fish in waterbodies that exceed human health thresholds as
identified by Oregon Health Authority (OHA 2010). Fish consumption advisories may be
issued to protect the general public or sensitive populations such as women of
childbearing age, nursing mothers, pregnant women, and children. When EPA initiated
this project, both ODEQ and OHA requested that the sampling be designed to support
establishment of an OHA fish consumption advisory, if warranted by the resulting data.
EPA agreed to focus the sampling design toward OHA's needs for advisories, rather
than sampling primarily for screening purposes.
EPA's study objective, therefore, was to collect mercury fish tissue concentration data to
support an OHA determination as to whether people are at risk of health impacts due to
elevated mercury from eating fish from this area and to assist OHA in communicating
that information to state and local decision makers and the public. This project is not
intended to investigate the sources of mercury in fish.
The main study questions are:
• What are mercury concentrations in the muscle tissue from commonly
consumed fish species in five sample waterbodies of NE Oregon?
• How do fish tissue mercury concentrations compare to OHA's mercury health
screening level?1
Fish were collected from five reservoirs in northeastern Oregon in June, 2011, and the
tissue was analyzed for mercury. The results from most of these measurements were
determined to be of sufficient quality and quantity to suit OHA protocols for developing
fish consumption advisories.
1 OHA will use these data to draw conclusions about health issues associated with consumption of
contaminated fish.
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Northeast Oregon Lakes Mercury
Study Area and Waterbody Selection
The general area of this study is the estimated area of elevated mercury deposition
predicted by the REMSAD model (Map 1). The REMSAD model is a coarse scale
model with a minimum cell size of 12 km2. We used proximity to the area of predicted
elevated mercury deposition as a starting place for selecting waterbodies to sample.
Publicly-managed fisheries within that area were identified as candidates for sampling.
Criteria used to identify the final list were: 1) proximity to the potential high deposition
zone identified by the model, 2) high use by anglers, 3) high consumption of resident
fish by anglers, and 4) availability and catchability of sport fish species. After evaluating
numerous waterbodies based on these criteria (see Appendix 1), five were selected for
sampling:
• Balm Creek Reservoir
• Bully Creek Reservoir
• Phillips Reservoir
• Powder River Arm of Brownlee Reservoir
• Thief Valley Reservoir
These reservoirs are described in Table 1 and their locations are shown on Map 1.
Table 1. Location and description of sample reservoirs.
Site Identification
Balm Creek Reservoir
Bully Creek Reservoir
Phillips Reservoir
Powder Arm Brownlee
Thief Valley Reservoir
County
Union
Malheur
Baker
Baker
Union/Baker
Basin
Powder River
Bully Creek
Powder River
Powder River
Powder River
Area
Sqkm
0.295
2.474
9.510
5.202
3.039
Elev
(ft)
4529
2513
4075
2075
3140
Lat_DD
44.970928
44.021791
44.677331
44.755474
45.025920
Long_DD
-117.492410
-117.401284
-118.007648
-117.131696
-117.790134
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Northeast Oregon Lakes Mercury
Enterprise
Joseph o
/
Mercury Deposition
Project Area
o. u
L, V fi:
"'. *•".
Wailowa \;
Imnaha
.-.. t - Wailowa Basin
:%.- >';>.- i, .- County
I
Upper Grande,.
Ronde Basin
i
*•
•<
'\ Halfway
Richland BrownleeDam
Greenhorn
N°"h,0
%
Burnt
Bas,n
Midvale
Legend
EPA REMSAD Modeling of Mercury Deposition for 2001
Ibs/square mile
00167-0.0700
00701 -01300
01301 -0.2300
02301 -04813
, Basin
ale Ontario'
•
ur
n
• -•
r7011 EPA Region 10 I ,T
Map 1. Northeastern Oregon Mercury Project Area showing model-predicted mercury deposition.
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Northeast Oregon Lakes Mercury
Target Species and Sample Hierarchy
In general, collecting fish for fish advisories involves targeting two fish species per
waterbody (EPA 2000). The levels of mercury in fish depend on what they eat, how long
they live and how high they are in the food chain (or their trophic level). Sampling two
species that occupy different trophic levels (open-water predators or bottom-dwellers,
for example) allows for a robust characterization of a chemical's presence in the fish
population. Also, sampling species from multiple trophic levels allows for both human
health and wildlife screening. This project is specifically focused on mercury presence in
fish consumed by humans so only species that are known to be caught and consumed
by anglers were targeted. Because mercury is known to bio-accumulate and reach
higher concentrations in higher trophic level species, predatory species were preferred.
Only predator species that are resident (non-migratory) and are known to be caught and
consumed by humans were targeted for sampling. Collection of fish of a single species
was considered the minimum sample with the option of sampling more than one
predator species as available. The predator species that were considered the best
targets were identified for each reservoir (See Appendix 1). Because these systems are
dynamic, the relative abundance of the species that are caught and consumed by
anglers can vary depending on the year/water conditions. Most sites have more than
one predator species that could be captured and still meet the sampling goal. A single
predator species was selected for sampling from each waterbody. Samples were
composites of 3 to 5 fish of a similar size. The sampling goal at each lake was two
composite samples from two size classes of the available predator species (plus a
replicate from each size class). Where the numbers and sizes of fish caught were
inadequate, the hierarchy shown in (Figure 1) was used to determine the species and
quantities that would make up the composite samples.
Adult fish that were within the length ranges typically consumed by anglers for each
species and within the legal limits as defined by the State of Oregon fishing regulations
(ODFW 2011) were eligible for inclusion in the sample. Inclusion of trout in the sampling
was carefully considered by reservoir. Small lakes in Oregon are commonly stocked
with fingerlings and sub-catchable sized trout. The study targeted only rainbow trout that
had over-wintered at least once and were of catchable/consumable size. Practical
considerations such as gear type, lake conditions, timing, and fish abundance dictated
the species actually captured.
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Northeast Oregon Lakes Mercury
Data adequate for consumption advisories
Priority 1 = 4 composites,* 2 size
classes, replicate for each
Priority 2 (a) = 2 composites, one
size class with replicate
Priority 2 (b) = 2 composites, two
size classes, but no replicate
Data adequate for screening**:
Priority 5 = single composite, One
size class, no replicate
Hierarchy and data adequacy determinations were based on EPA guidance and are consistent with
use in other West Coast States:
USEPA Office of Water 2000, Guidance for Assessing Chemical Contaminant Date for Use in Fish
Advisories
California EPA 2005, General Protocol for Sport Fish Sampling and Analysis
WA Dept of Health, draft 2004 "Protocol for Fish Consumption Advisories in Washington State"
'All composites will be made up of 3-5 individuals within a single size class (75% of length range)
"Screening data do not form an adequate basis for issuance of consumption advisories, but may
indicate the need for additional sampling
Figure 1. Hierarchy for fish advisory for NE Oregon lake fish tissue study used to guide fish collection.
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Northeast Oregon Lakes Mercury
Methods
The methods were designed to efficiently sample for total mercury to generate data
useful for fish consumption advisories, or screening level analysis (if inadequate
numbers offish are collected for advisories). Screening-level data, although not
adequate for advisories, may indicate the need for additional sampling in the future.
Field Methods
All field sampling activities followed procedures in the project's QAPP (US EPA 2011)
with the objective of maintaining sample integrity from the time of fish collection through
sample shipment to arrival at the laboratory. Fish were collected using gillnets at all
waterbodies except the Powder River Arm of Brownlee Reservoir where boat
electrofishing was used. Fishing was a collaborative effort, with ODFW participating at
four of the five waterbodies and Idaho Power Company (IPC) participating with fish
collection on the Powder River Arm of Brownlee Reservoir. All sites were sampled
between June 14th and 17th, 2011.
Captured fish were identified to species and measured for length. Individuals meeting
the species and size criteria were retained. Each composite sample consisted of similar
sized fish (each fish within 75% of the length of the other individuals in the 3-5 fish
sample). Whole fish were weighed, packaged, preserved on dry ice, and delivered to
the EPA Region 10 Laboratory in Manchester Washington where they were stored at
-20°C.
Laboratory Fish Processing Methods
Initial processing was conducted in September 2011. Equal portions of muscle tissue
(skinless) were removed from each fish so that individuals were equally represented in
the composite sample. Tissues were then combined and homogenized in a mini-blender
(Figure 2). A total of approximately 40 grams of tissue per fish was used for each
composite sample. The homogenized samples were stored at -20°C until final
processing.
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Northeast Oregon Lakes Mercury
Figure 2. Fish tissue processing: tissue excision and blending composited tissue.
The chemical analysis was performed by EPA chemists following standard operating
procedures for digestion and analysis in order to achieve the required measurement
quality objectives. These are described in detail in the QAPP for this project (See
Attachment 1). The wet tissue was digested and analyzed using EPA method 245.6
(USEPA 1991). The reporting limits for mercury were 0.0125 mg/kg.
Data Summary Methods
All results are reported separately for each species on a site by site basis. Since
samples were analyzed as composites, only one value is reported per sample. In cases
where there are replicate samples, data are reported as means of the two composites.
To aid the reader in interpreting the concentrations, the data are compared to 1)
threshold values used by Oregon Health Authority for fish advisory screening (OHA
2010), 2) other fish tissue mercury data collected from these reservoirs, and 3) data
from large scale studies conducted in the Pacific Northwest region.
Results
Sampling Results
Of the fish captured and retained as samples, all were considered target species as
they met the study criteria of resident predators within appropriate size specifications
that represent fish commonly captured and consumed by anglers (see QAPP). A total of
19 samples were collected from the five waterbodies. No single species was captured
consistently across all the sampled reservoirs.
Sample results are shown in Table 2. The Powder River Arm of Brownlee Reservoir
had the most species sampled with composites from four different target species.
Three waterbodies- Balm Creek Reservoir, Bully Creek Reservoir, and Phillips
Reservoir, had only one species sampled. An adequate number of individuals, useable
for fish advisory level evaluation, was collected for a minimum of one species at each of
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Northeast Oregon Lakes Mercury
four reservoirs. At Bully Creek Reservoir, however, only two channel catfish were
captured. These two fish were analyzed as individuals (not composited) because only
two fish would be an inadequate composite and they would be more valuable for
screening level analysis for this reservoir as individual samples.
Analysis Results
Mercury analysis results were generated for all 19 samples. Replicate samples were
collected for eight of the species/size/reservoir combinations. These are presented as
mean values in Table 2. Quality assurance review was conducted on all samples plus
two duplicates and one rinsate. All measures of quality control met the laboratory and
QAPP criteria (US EPA Region 10 Memo 2011).
Table 2. Northeast Oregon fish sampling results.
Waterbody
Fish Species Fish
per
sample
Balm Cr.
Balm Cr.
Balm Cr.
Bully Cr.
Bully Cr.
Phillips R.
Phillips R.
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Powder Arm
Thief Valley
Thief Valley
Thief Valley
rain bow trout (sm)
rain bow trout (Ig)
rain bow trout (Ig)
channel catfish
channel catfish
yellow perch
yellow perch
black crappie
black crappie
bluegill (sm)
bluegill (sm)
bluegill (Ig)
smallmouth bass
smallmouth bass
white crappie
white crappie
bluegill
rain bow trout
rain bow trout
4
3
4
1
1
5
5
5
5
5
5
3
4
4
4
4
5
3
4
Length Hg cone. Species
Range Wet wt. Mean
(mm) (mg/kg)
270-306
345-392
335-398
470
356
195-208
193-230
242-263
240-265
173-184
171-183
220-233
305-355
306-344
266-282
282-316
140-170
283-295
300-325
0
0
0
0
0
0
0
0
099
131
139
207
288
558
604
380
0
0
0
0
123
248
581
395
Size
Class
Size Sample
(n)
Mean
0
0
0
0
0
099
135
248
581
395
small
large
all
all
all
1
2
2
2
2
0.410
0
0
0
0
0
0
0
0
0
0
122
137
329
287
344
325
353
247
053
069
0
0
0
0
0
196
316
339
247
061
0
0
0
0
0
0
130
329
316
339
247
061
small
large
all
all
all
all
2
1
2
2
1
2
Mean total mercury concentrations (expressed as wet weight) ranged from a low of
0.061 mg/kg in rainbow trout of Thief Valley Reservoir to a high of 0.58 mg/kg in yellow
perch of Phillips Reservoir (Table 2). Rainbow trout collected in both Balm Creek
Reservoir and Thief Valley Reservoir had relatively low total mercury concentrations
compared with other species (Figure 3).The small-sized bluegill collected in the Powder
8
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Northeast Oregon Lakes Mercury
River Arm of Brownlee Reservoir also had low total mercury concentration (mean 0.13
mg/kg).
Figure 3. Graph of mercury concentration in fish species by water body. Where replicate samples were
collected, data are presented as mean values as shown on Table 1. Purple line indicates current advisory
threshold of 0.23 mg/kg used byOHA.
Discussion
A. Thresholds for evaluating need for fish advisories
The screening level thresholds for mercury depend on the fish consumption rate used.
The more fish consumed, the lower the screening level. Oregon Health Authority
currently uses a level of 0.23 mg/kg of Hg, which assumes up to 4 meals per month of
fish for an adult. This calculation is based on the method in EPA's Fish Advisory
Guidance (USEPA 2000). There may be local anglers who consume more than one
meal of fish per week, and therefore a fish advisory calculated for only four meals per
month may not be protective of those individuals. However, health agencies also
consider the benefits of fish consumption, so they do not want to express advisories in a
way that is overly cautious and may discourage people from consuming fish at all.
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Northeast Oregon Lakes Mercury
B. Relevance to Fish Advisories
Phillips Reservoir
Based on these 2011 sample results, Phillips Reservoir is a candidate for development
of a fish advisory for consumption of yellow perch. The mean of two samples was 0.581
mg/kg, substantially higher than the 0.23 mg/kg threshold value. These results confirm
previous data collected from Phillips in 1994, which showed that mercury concentrations
were slightly elevated above threshold levels2 in both smallmouth bass and black
crappie (Table 3). Like yellow perch, both of these species are consumed by anglers.
Although this is a limited dataset, it does show that elevated concentrations of mercury
have been found in fish tissue from Phillips Reservoir for almost two decades.
Table 3. Data collected from Phillips Reservoir on September 27,1994 from the deepest part of the lake
(unpublished data provided by OHA).
Species
smallmouth bass
smallmouth bass
smallmouth bass
smallmouth bass
smallmouth bass
Hg
(mg/kg)
0.27
0.39
0.39
0.40
0.41
Age
3
4
3
3
3
Length
250
250
220
235
265
Weight
(grams)
185
185
120
155
235
Species
mean
0.37
black crappie
black crappie
0.35
0.39
3
5
205
250
125
205
0.37
rain bow trout
rain bow trout
rain bow trout
0.14
0.15
0.16
1
1
1
230
225
220
95
95
95
0.15
Powder Arm of Brown lee Reservoir
A sport fish consumption advisory has been in effect for Brownlee Reservoir since 1997
(OHR 1997). This advisory states that fish mercury concentrations of 0.41 mg/kg
prompted the advisory, as this level exceeds the threshold of 0.35 mg/kg used at the
time. Species-specific data were not presented in the Advisory. Past fish tissue
analyses in Brownlee Reservoir yielded results similar to our 2011 study. A 1997 study
of trace elements in fish tissue from the lower Snake River Basin found mercury levels
of 0.30, 0.27, and 0.33 mg/kg wet weight in smallmouth bass, white crappie, and
channel catfish fillets, respectively in Brownlee Reservoir (USGS 1998). A 2006 TMDL
study of Brownlee Reservoir mercury found levels ranged from 0.48 to 0.78 mg/kg wet
weight in smallmouth bass fillet composite samples from various locations (IDEQ 2006).
Oregon used a higher threshold concentration (0.35 mg.kg) for setting advisories in 1994
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Northeast Oregon Lakes Mercury
The 2011 results from the Powder River Arm of Brownlee Reservoir (Table 2) are
similar to what has been found in past data. White crappie, smallmouth bass, and large-
sized bluegill samples exceeded 0.30 mg/kg and black crappie exceeded 0.40 mg/kg.
C. Comparison with regional studies
Fish tissue mercury concentrations from the five Northeast Oregon reservoirs were
compared to three large-scale studies in the area to provide context for these results.
The three studies are briefly described below. All studies used composite samples and
methods protocols similar to those used in this Northeast Oregon study. Summarized
results are in Table 4.
Idaho Statewide study: Fifty lakes were assessed using a random design that was
stratified by lake size. The study analyzed 89 composite samples (fillets) from 20
different species (Essig and Kosterman 2008). Samples were classified as salmonids
(37 samples) or spiny ray species (52 samples).
National Lake Fish Tissue Study (Pacific Northwest Region): A nationwide study of
contaminants in fish tissue collected samples from 500 lakes between 2000 and 2003
(Stahl et al. 2009). Lakes were selected using a random design that was stratified by
lake size. Thirty of the lakes sampled were in the Pacific Northwest region (PNW from
here on), which includes Idaho, Oregon, and Washington. Samples were collected from
16 different species in the PNW region. The analysis grouped fish species into either
predators (trout, bass) or bottom-dwellers (suckers, carp, and catfish). Twenty eight
predator samples and 19 bottom-dweller samples were analyzed (Merger et al. 2011).
Table 4 includes only the predator species data from that study.
Northeast Washington background study: This study focused on sampling lakes
considered to have background condition for contaminants. Lakes in northeastern
Washington were selected based on having relatively low impact from human activities
and low likelihood of local contamination sources. Mercury was analyzed from fish fillets
from 31 composite samples collected from 13 lakes and three rivers, in 2010-2011.
Fourteen species were sampled (8 salmonids and 6 spiny ray samples). This study also
included the upper Priest Lake and Upper Joe River, both located in Idaho.
11
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Northeast Oregon Lakes Mercury
Table 4. Summary of fish tissue mercury concentrations from other studies in the area compared to the
NE Oregon results (units in mg/kg wet weight).
Study group
NE Oregon
PNW regionwide1
NE Oregon
Idaho statewide2
NE WA background3
NE Oregon
Idaho statewide
NE WA background
Mean
Median Min. Max.
Sample N
Predator Species
.267
.198
.287 .053 .604
.133 .023 .601
19
28
Salmonid Species
.098
.151
.069
.099 .053 .139
.103 .026 .723
.047 .018 .214
5
37
17
Spiny Ray Species
.327
.319
.169
.327 .122 .604
.243 .020 1 .380
.186 .029 .492
14
52
14
1 .Merger et al. 2011 2. Essig and Kosterman 2008 3. Johnson et al. 2011
None of the three comparison studies provides a perfect comparison with the Northeast
Oregon study because they were undertaken for different purposes, have different
sample designs, and used different classifications of the fish. They do provide a useful
context for the Northeast Oregon data if these differences are taken into account.
Comparing the predator species samples between Northeast Oregon study and the
PNW region-wide study shows the mercury concentration is higher in the Oregon study
(Figure 4). One factor that affects these results is that the random lake selection for the
region-wide study includes a broader diversity of ecological conditions. For example, the
PNW lake survey includes pristine high elevation lakes within National Parks as well as
reservoirs of the Columbia River. Also, the PNW sample includes one sample each from
28 lakes. In contrast, the 19 samples for the NE Oregon lakes are all from the five
targeted Oregon reservoirs.
The comparison of salmonid species and spiny ray species results among the studies
shows the Northeast Oregon results are similar to the Idaho statewide results
(Figure 4). The background study of Northeast Washington has results lower than the
other studies for both the salmonid species and the spiny ray species. This is an
expected result as these lakes were selected for their lack of human disturbance and
contamination sources.
Results from the studies described here consistently show lower mean mercury
concentrations in salmonids versus spiny ray species. This is an expected result as
salmonid species often feed at a lower trophic level compared to spiny ray species,
which tend to be piscivorous. For example, rainbow trout and whitefish are
12
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Northeast Oregon Lakes Mercury
insectivorous. The exceptions would be char species such as lake and bull trout and
brown trout, which are more piscivorous in their feeding habits.
350
350
Predator Species
NE Oregon
Salmonid Species
PNW study
NE Oregon Idaho statewide NEWA background
Spiny Ray Species
NE Oregon
Idaho statewide NE WA background
Figure 4. Comparison of NE Oregon fish tissue mercury concentration means and medians to results
from other studies (sources: Essig and Kosterman 2008, Merger et al. 2011, Johnson et al. 2011).
13
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Northeast Oregon Lakes Mercury
Conclusions
The data collected during this study provide insight into the general mercury content in
fish of Northeast Oregon reservoirs. These data were intended to be useful to OHA to
support development of fish advisories, as appropriate. The data do support a new fish
advisory on Phillips Reservoir for yellow perch and show the continued need for an
advisory on Brownlee Reservoir for select species. In addition, new information was
acquired on mercury levels in three other reservoirs that have not been assessed to
date. This work, of course, leads to more questions. The following are data gaps that
would be useful to fill as resources become available:
• Screening level sampling at Bully Creek Reservoir and sampling of only one
centrarchid species in Thief Valley Reservoir yielded results just above the
threshold value of 0.23 mg/kg, suggesting that more sampling would be
warranted. Data gaps include bass and crappie species in Bully Creek, Phillips,
and Balm Creek Reservoirs, and yellow perch in Thief Valley Reservoir.
• Additional evaluation of the REMSAD model's 'significant deposition area' could
be done to identify other waterbodies that have substantial use by anglers yet
lack data on mercury concentrations. If candidate waterbodies meet criteria,
consider a second phase of sampling.
14
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Northeast Oregon Lakes Mercury
References
Clark, G.M. and T.R. Maret. 1998. Organochlorine Compounds and!race Elements in
Fish Tissue and Bed Sediments in the Lower Snake River Basin, Idaho and Oregon.
U.S. Geological Survey Water-Resources Investigations Report 98-4103. U.S.
Geological Survey, Boise, Idaho.
Essig, D.A. and M. A. Kosterman. 2008. Arsenic, mercury, and selenium in fish Tissue
from Idaho lakes and reservoirs: A statewide assessment. Idaho Department of
Environmental Quality. Boise, Idaho. 80pp.
Merger, L.G, P.T. Leinenbach, and G.A. Hayslip. 2011. Ecological condition of lakes in
Idaho, Oregon, and Washington (Appendix 4). EPA-910-R-11-001. U.S. Environmental
Protection Agency, Region 10, Seattle, Washington.
ICF Consultants Inc. 2008, Model-based Analysis and Tracking of Airborne Mercury
Emissions to Assist in Watershed Planning, prepared for EPA Office of Water,
Washington, D.C., final report August 5, 2008, 350 p.
IDEQ. 2006. Brownlee Reservoir Mercury TMDL Fish Tissue Study Results and Field
Summary. Prepared by Hawk Stone. Idaho Department of Environmental Quality.
Boise, ID. Available online at: http://www.deq.idaho.gov/water-quality/surface-
water/mercury.aspx.
Johnson, A., M. Friese, J. Roland, C. Gruenenfelder, B. Dowling, A. Fernandez, T.
Hamlin. 2011. Background levels of metals and organic compounds in Northeast
Washington lakes Part 2: fish tissue. Publication No. 11-03-054. Washington State
Department of Ecology Olympia, Washington. This report is available on the
Department of Ecology's website at www.ecv.wa.gov/biblio/1103054.html
Oregon Department of Fish and Wildlife. 2011. 2011 Oregon State Sport Fishing
Regulations. Oregon Department of Fish and Wildlife, Fish Division - Angling
Regulations Coordinator. Salem, OR.
Oregon Health Authority. October 11, 2010. DRAFT. Fish consumption advisory:
Standard Operation Guidance (SOG) for the Oregon Health Authority. Portland, OR.
Oregon Human Resources, Health Divison. April 28 1997. Fish Advisory: elevated
levels of mercury in sport-caught fish in the Snake River. Oregon Health Division.
Portland, Oregon. Available at:
http://public.health. Oregon. gov/newsadvisories/Pages/RecreationalAdvisories.aspx#fish
15
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Northeast Oregon Lakes Mercury
Stahl, L.L., B.D. Snyder, A.R. Olsen, and J.L. Pitt. 2009. Contaminants in fish tissue
from U.S. lakes and reservoirs: a national probabilistic study. Environmental Monitoring
and Assessment. 150:3-19.
US EPA. 2011. Quality Assurance Project Plan (QAPP) for the Northeastern Oregon
mercury in fish tissue assessment. Prepared by US EPA Region 10, Office of
Environmental Assessment. Seattle, WA.
US EPA, 2010. Guidance for Implementing the January 2001 Methylmercury Water
Quality Criterion. EPA 823-R-10-001. USEPA. Washington, D.C.
US EPA. 2000. Guidance for Assessing Chemical Contaminant Data for Use in Fish
Advisories, Volume 1: fish sampling and analysis. Third Edition. EPA 823-B-00-007.
USEPA. Washington, D.C.
US EPA. 1991. EPA Method 245.6 Determination of Mercury in Tissues by Cold Vapor
Atomic Absorption Spectrophotometry. EPA Environmental Monitoring Systems
Laboratory. Office of Research and Development.
US EPA Region 10. 2011. Quality Assurance Memorandum for Inorganic Chemical
Analysis: Quality Assurance Review of NE Oregon Mercury in Fish Tissue for Mercury
November 22,2011 to L. Merger and L. Edmond From K. Adams Office of
Environmental Assessment, US EPA Region 10 Laboratory. Project Code: ESD-218A.
16
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North east Oregon Lake Hg
Appendix 1. List of lakes considered for sampling in northeastern Oregon.
Waterbody
Powder Arm,
Brownlee Resr.
Highway 203
Pond
Burnt River
Catherine Cr.
Powder River
Bully Cr Resr.
Phillips Resr.
Thief Valley
Resr.
Pilcher Resr.
Malheur Resr.
Balm Cr Resr.
Unity Resr.
Grande Ronde
Beulah Resr
Warm Springs
Resr.
Pole Cr Resr
WolfCr. Resr.
Deposition
Zone Prox.
high
high
high
high
high
med
med
med
med
med
med
low
low
low
low
low
med
Possible target
species
Sm. Lm. bass, bl.
Wh. crappie, y.
perch, catfish sp.
bass (small),
bluegill (small)
bass, trout
(natural)
carp, trout
adult trout below
Thief Valley Resr.
bass, crappie
y.perch, sm Im
bass, black
crappie,
trout (fingerlings
stocked), y. perch
crappie
trout (fingerlings
stocked)
Sm bass, black
crappie
bass, crappie
Bass,, trout
trout
bass, perch, trout
crappie, catfish
trout
crappie
Other species
trout (catchable-size
stocked)
trout (catchable-size
stocked)
trout (catchable-size
stocked)
Channel catfish
trout (fingerlings and
sub-catchables
stocked), suckers,
walleye
Bluegill, b. crappie
trout (fingerlings
stocked)
trout (fingerlings
stocked)
trout (fingerlings
stocked),
trout (fingerlings
stocked)
Fish
consumption
high
high trout; low
bass
low
low (some
trout)
medium
high
high
high (mostly
trout)
high trout;
med. crappie
medium
medium with
high potential
high
low
unk.
unk.
unk.
sometimes
high
Methyl ation
potential
high
unk.
unk.
unk.
unk.
high
unk.
high
unk.
med
unk.
unk.
high /unk
unk.
unk.
unk.
unk.
Condition
Comments
eutrophic
low gradient
Elev fluctuates;
eutrophic
Elev.fluctuates
Elev. fluctuates;
eutrophic
Elev. fluctuates
Elev. fluctuates
Elev. fluctuates
low gradient
Draft Recommendation for
Inclusion in Sampling
Y - Both ODEQ and ODFW have
highlighted this area
Probably N - stocked trout not
likely to substantially accumulate
Hg; bass & bluegill very small
Y- bass available
Maybe - may be info on GR
Basin
Probably N- Thief Valley and
Brownlee Arm part of Powder R.
Y
Y
Y
Maybe
Maybe - Only trout caught (But
premier trout fishing spot)
Maybe - Close proximity to
yellow zone.
Maybe, but more distant
Fairly Distant —
N due to distance and species
Fairly Distant -> Maybe Later if
Subsequent Sampling
Need to verify exact location
Maybe
Proximity to REMSAD zones (map 1): H=in red or yellow; M=within 24km of red/yellow; L > 24 km from red/yellow.
A1
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