“Our waters, our fish, our people”
Mercury contamination in fish resources of two Treaty #3
communities
Research Question
• Do our fish still contain high levels of Hg?• Is it possible that some fish species in
some lakes are clean enough to eat?• How much fish can we eat without the fear
of Hg poisoning?• Can we set up a monitoring program
ourselves to check the Hg levels in fish?
Grassy Narrows Territory Wabaseemoong Territory
Clay Lake Winnipeg River
Ball Lake Caribou River
Maynard Lake Tetu Lake
Indian Lake Swan Lake
Separation Lake Old Man Lake
Tide Lake Goshawk Lake
Garden Lake
Ball Lake trendline
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
20 30 40 50 60 70 80 90
length (cm)
Ball lake
Clay lake
Garden
Indian lake
Maynard lake
Separation
Tide lake
Walleye
Clay Lake Trendline
0.000
0.100
0.200
0.300
0.400
0.500
0.600
35 40 45 50 55 60
length (cm)
Ball lake
Clay lake
Garden lake
Indian lake
Maynard lake
Separation lake
Tide lake
Whitefish
Clay Lake Trendline
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
15 20 25 30 35 40 45 50length (cm)
Ball lake
Clay lake
Indian lake
Maynard lake
Separation lake
Bass
Clay Lake Trendline
0.000
1.000
2.000
3.000
4.000
5.000
6.000
7.000
30 40 50 60 70 80 90 100 110
length (cm)
Ball lake
Clay lake
Indian lake
Garden lake
Separation lake
Tide lake
Maynard
Northern Pike
Hg in Clay Lake
Species
Scott (1974) Present study (2003)
N Avg Hg (mg/kg)
length range(cm
)N Avg Hg
(mg/kg)
Length range(cm
)
Walleye 508 7.10 15.3-71.1 20 2.98 28.0-69.0
Northern Pike 497 5.97 21.2-80.3 20 2.14 39.0-68.0
Whitefish 234 1.83 25.7-52.5 19 0.31 44.0-54.0
Hg in Walleye from Ball Lake
YearN Hg (mg/kg)
1971 60 1.99
1972 45 2.71
1976 46 1.39
Present study (2003)
20 0.40
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100 120 140 160 180 200
distance downstream from Dryden (miles)
Con
cent
rato
n H
g (u
g/g)
1973
Indian Lake
Ball Lake
Clay Lake
Tetu LakeIndian LakeBall Lake
Clay Lake
2003
Mercury Contamination in Walleye
Table 20: Average Hg Levels Fishing Popularity of Specific Lakes
Grassy Narrows
Lake Average Level of Hg
# Participants Fishing (% of Population)
Clay 2.982 7 (13%)
Ball 1.070 18 (34%)
Tide 0.979 24 (45%)
Indian 0.643 36 (68%)
Seperation 0.600 39 (74%)
Garden 0.575 45 (85%)
Maynard 0.417 47 (89%)
Table 1: Participant Profile of Each Community
Grassy Narrows GN %Wabaseemoon
g WD %
Total n 87 100% 55 100%
Sampled 52 60% 41 75%
Volunteered 35 40% 14 25%
Male 51 59% 21 38%
Female 36 41% 34 62%
18-40 55 63% 35 64%
41-60 21 24% 16 29%
61+ 11 13% 4 7%
0.00
5.00
10.00
15.00
20.00
25.00
30.00
0-4 5-9 10-19 20-39 40-59 60-79 80-99 100-199 200-299
Average Total Fish (g/day)
# 0f
Par
ticip
ants
Distribution of Average Fish Intake – Grassy Narrows
Table 20: Average portion size for a fish meal (g/meal) (mean ± SD)
Grassy Narrows
Walleye 276 ± 134
Whitefish 232 ± 167
Bass 255 ± 192
Northern Pike 180 ± 145
Average Fish Intake - Grassy Narrows By Gender
Group
0.00
10.00
20.00
30.00
40.00
50.00
60.00
Average Summer Fall Winter Spring
Season
Ave
rage
Inta
ke (g
of f
ish/
day)
Local Fish
Market Fish
Male Female Male FemaleMale FemaleMale FemaleMale Female
Average Fish Intake - Grassy Narrows By Age Group
0.00
10.00
20.00
30.00
40.00
50.00
60.00
Average Summer Fall Winter Spring
Season
Ave
rage
Inta
ke (g
of f
ish/
day)
Local Fish
Market Fish
18-40 41-60 60+ 18-40 41-60 60+18-40 41-60 60+18-40 41-60 60+18-40 41-60 60+
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
18-40 41-60 61+
Ave
rage
Mer
cury
Exp
osur
e (u
g/kg
bod
y w
t/day
)
femalemale
Average Mercury Exposure by Age and Gender Group – Grassy Narrows
Distribution of Mean Hair Mercury Concentrations – Grassy Narrows
0
5
10
15
20
25
30
belo
w D
L
DL-
1.00
1.00
1-2.
00
2.00
1-3.
00
3.00
1-4.
00
4.00
1-5.
00
5.00
1-6.
00
6.00
1-7.
00
7.00
1-8.
00
Mean Hair Hg (ppm)
# of
Par
ticip
ants
Estimated Mercury Exposure and Measured Hair Level - Grassy Narrows
0
1
2
3
4
5
6
7
8
0 0.5 1 1.5 2 2.5
Intake (ug Hg/kg body wt/day)
Hai
r (pp
m)
Profile of participants with high Hg intake in Grassy Narrow
ParticipantMean Hair Hg (ppm) Age Gender
Average Fish Consumption
(g/day)
Estimated Hg Exposure
(ug/kg body wt/ day)
GN104 7.2 52 Male 10 0.3
GN118 7.4 49 Male 276 0.7
RecommendationGrassy Narrow
• Currently, there is no problem with high Hg exposure from eating fish
• Do not eat fish from Clay and Ball Lake• Promote eating more fish, particularly
whitefish up to 5 fish meal per week• Walleye may be limited to 2 fish meal
every 3 weeks for those who are concerned.
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