Mercury Monitoring on the Fond du Lac

Reservation

Joy Wiecks, Air Quality TechnicianFond du Lac Band of Lake Superior Chippewa

December 15, 2005

WRAP Board Meeting

FDL Mercury Monitoring Program

Reservation OverviewEnvironmental MercuryMercury in MinnesotaMercury and FDL Natural ResourcesSite HistoryDataFDL Advisories and Other ProjectsFuture Studies

Fond du Lac Reservation

Located in Northeastern Minnesota.Rural area about 20 miles from

Duluth/Superior.Reservation has 108 water bodies,

totaling 2850 acres – lots of wetlands.Ceded Territories cover 8 million acres.

About Environmental Mercury

Silvery, liquid metal at room temperature. An element – does not break down. When released, evaporates and circulates in the

atmosphere until deposited in lakes and oceans. Bacteria and chemical reactions that take place in

water cause mercury to change into a more toxic form called methylmercury.

Methylmercury builds up in the bodies of plankton, fish, humans, and other animals and is a neurotoxin.

Mercury on the Reservation

Mercury is a concern because the boreal forest/wetland ecoregion is very sensitive to mercury deposition.

Methylation more likely to occur due to watershed characteristics.

Higher risk for bioaccumulation and human exposure due to the presence of fish-eating species.

Clean Air Mercury rule unlikely to lead to reductions in our region.

Mercury in Minnesota(Year 2005 Data)

In 2005, about 3,341 lbs will be released in Minnesota (down from 3600 lb in 2000).

98% of this was discharged to the atmosphere. Only 10-30% of deposition comes from in-state sources. 58% of mercury emitted comes from energy production (up

from 51%). 22% is from “purposeful uses”, including latex paint,

fungicides, waste combustion, fluorescent lamp breakage, dental preparations, etc (down from 28%).

20% is from materials processing (taconite mining, pulp and paper) (down from 21%).

Mercury and Fish Consumption

Consumption of large game-fish can lead to mercury poisoning in humans.

Native populations at risk because of consumption of fish as a traditional food source.

Mercury poisoning can cause damage to the nervous system and is especially harmful for small children and developing fetuses.

Animals can suffer effects, too. Threshold for effects unknown!! Advisories just a starting point. Great Lakes Indian Fish and Wildlife Commission consumption

study versus EPA’s CAMR numbers.

Natural Resources at FDL

Fish harvests (2002):From Mille Lacs, total tribal take was about

54,000 pounds of walleye. FDL harvest was about 7,142 pounds.

Rice harvested: 20,000-25,000 lb/yrMoose harvested: 38 in 2001Waterfowl harvested: est. <500/yr

Precipitation Deposition Site History

Site established in 1997 in cooperation with Glass and Sorensen at University of Minnesota – Duluth (UMD) and with Cloquet Forestry Center. Monitor – principle of operation. Analytical method is cold vapor atomic absorption. Sample collected every Tuesday and delivered to UMD.

Updates at site Replaced old M.I.C. monitor with NTN monitor (2002)

although not using NTN analysis. Started analyzing for methyl mercury in Sept. 2000.

Data

Total mercury data shows spring-thru-fall spikes.

Total mercury concentration ranges from 1.2 – 2470 ng/L.

Methylmercury data seems to show spikes in summer/fall.

Methylmercury as a percentage of total mercury ranges from 0.2% (7/01) to 16.8% (4/03).

Total Mercury Data

Methyl Mercury Data

Sediment Assessment

In 2000, GLNPO funded study of 12 reservation lakes: characterize sediments, assess contaminant levels in bioavailable portion (Hg, Pb, PCB’s), toxicity tests.

Sediment quality database developed; an additional indicator of reservation water quality.

Found higher Hg values associated with organic sediments. 30 of 96 sites had dry wt Hg exceeding Level 1 Sediment Quality

Threshold of 0.18 ug/g. Shallow lakes had consistently higher Hg levels. No PCB problems were found but some elevated Pb levels were

observed, theorized to be from lead shot in the sediment.

Phase II Sediment Study

Second GLNPO project (2002) included 12 St. Louis River sites; same parameters plus methyl mercury.

Analyzed archived samples from Phase I for meHg.Added results to database.Correlated sediment quality and water quality

parameters and watershed factors.Got a good handle on degree of Hg in water

bodies.

0

50

100

150

200

250

300

StL

R

Big

Joe

Mar

tin Los

t

Third

Wes

t Tw

in

Soph

ie

Perc

h

Pat M

artin

Ric

e Po

rtag

e

Dea

d Fi

sh

Sim

ian

Tot

al H

g C

once

ntra

tion

, ng/

g dw

Average Across Sites for Each Water Body

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6Pa

t Mar

tin

Lost

Big

Joe

Mar

tin

StLR

Perc

h

Wes

t Tw

in

Ric

e Po

rtage

Dea

dfish

Soph

ie

Third

Sim

ian

Ave

rage

MeH

g C

onc.

(dry

wt)

, ng/

g

All Lakes

R2 = 0.31

0.01

0.10

1.00

10.00

0 50 100 150 200 250 300

Total Hg Conc., ng/g dw

MeH

g C

onc.

, ng/

g dw

West Twin

R2 = 0.66

0

50

100

150

200

250

0 1 2 3 4 5

Water Depth, m

To

tal

Hg,

ng/

g d

w

North Basin

South basin

Perch Lake

R2 = 0.53

0

50

100

150

200

250

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Water Depth, m

Tot

al H

g C

onc.

, ng

/g d

w

North Basin

South Basin

Lake Averages

R2 = 0.86

0

50

100

150

200

250

0 5000 10000 15000 20000

Total Watershed

Tot

al H

g C

onc.

, ng/

g

R2 = 0.8

0

50

100

150

200

250

0.1 1.0 10.0 100.0

Wetland / Water Area

Tot

al H

g C

onc.

, ng/

g

Lake Averages

R2 = 0.839

0.0

50.0

100.0

150.0

200.0

250.0

0 50 100 150 200 250 300

Color, Pt-Co

Tot

al H

g, n

g/g

Lake Averages

R2 = 0.43

0.0

50.0

100.0

150.0

200.0

250.0

0 1 2 3 4 5 6

TSS, mg/L

Tot

al H

g, n

g/g

0.0

50.0

100.0

150.0

200.0

250.0

0 20 40 60 80 100 120 140

ANC

Tot

al H

g, n

g/g

Fish Tissue Samples

In 2000, FDL partnered with the MN Dept of Health to study fish contaminants, develop culturally sensitive consumption guide.

Fish collected from St. Louis River and 7 Reservation lakes; targeted species that are commonly eaten. Also lists non-native species (tuna, shark).

Mercury drives consumption restrictions (PCB’s and other contaminants ruled out).

Produced fish advisories and a guide for expectant mothers.

Wild Foods StudyComprehensive risks/benefits analysis funded by

MN Sea Grant.Cultural and nutritional benefits of wild foods (vs.

market alternatives) offset contaminant exposure.Wild rice, waterfowl, moose analyzed for Hg, Pb.Waterfowl and fish have comparable Hg.Moose livers found to be high in cadmium, no Hg

uptake found in rice..

Future Studies

Sampling more waterfowl.Continuing fish tissue analysis.Continuing atmospheric deposition

monitoring (currently total Hg only).Investigate potential sediment mercury

mitigation techniques.