“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)

NAvg 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)

Co

nce

ntr

ato

n H

g (

ug

/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

Pa

rtic

ipa

nts

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

Av

erag

e In

take

(g

of

fis

h/d

ay)

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

Av

erag

e In

take

(g

of

fis

h/d

ay)

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+

Av

era

ge

Mer

cu

ry E

xp

os

ure

(u

g/k

g b

od

y w

t/d

ay)

female

male

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

-1.0

0

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)

# o

f P

art

icip

an

ts

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)

Ha

ir (

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.