Spatial variation in methylation rates in

Farmington and Ogden Bays

Ms. Abigail Rudd, Dr. Diego Fernandez,

Mr. Greg Carling, Prof. William Johnson

University of Utah, Geology & Geophysics

Funded by Forestry, Fire, and State Lands

0

2

4

6

8

10

12

14

16

18

20

DO

(m

g/L

)

x

7.8

8.0

8.2

8.4

8.6

8.8

9.0

9.2

9.4

pH

x

DO

pH

1.20

1.40

1.60

1.80ug/L

x

Se

0.00

1.00

2.00

3.00

4.00

0 5 10 15 20

Time (MST)

ng/L

x

Hg

1200 1600 2000 0200 0600 1200

Selenium & Mercury at Ambassador Duck Club

Greg Carling University of Utah

Howard Slough outfallJuly 23-24, 2008

Ambassador W-1 outletAugust 20-21, 2008

(Howard Slough data from David Naftz)

methylHg

(ng/L)

0.03

0.05

0.07

0.09

0.11

0.13

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

0100

0200

0300

0400

0500

0600

0700

0800

0900

1000

1100

1200

(from USGS Fact Sheet 146-00)

Complex processes controlling methyl Hg

GunnisonBay

Bear River Bay

Bear River

GilbertBay

Weber River

Jordan River

OB-1

OB-2

OB-3OB-4

OB-5

Ogden Bay

Farmington Bay

auto causeway opening (bridge)

FBN-1

FBN-2FBN-3

FBN-4

FBN-5

Jordan River

FBS-1FBS-2

FBS-3FBS-4

FBS-5

Measuring Hg methylation

TotalHg

MethylHg

TotalHg

MethylHg

Hg2+

spike

Initial sample Spike Later sample

MeHg = 30%Extraction efficiency not consistent

enough to reliably measure

MeHg

204

TotalHg

MethylHg

202

TotalHg

MethylHg

204Hg2+

spike

Me204Hg

Me204Hg is 300%Can reliably measure

Initial sample Spike Later sample

HgMekHgMeHgTkdt

HgMeddemethmeth

204204204204

tMeHgktMeHgTHgkMeHg

tMeHgktMeHgTHgkMeHgtR

tdemethtmetht

tdemethtmethtMeHg

2041

2041

2041

2021

2021

2021204/202 )(

HgMek

HgMek

HgMeHgTk

HgMeHgTk

HgMe

HgMe

dt

dR

dt

d

demeth

demeth

meth

methMeHg 204

202

204204

202202

204

202204/202

0

1

2

3

4

5

0 20 40 60 80

R2

02

/20

4M

eH

gFBN-1 summer

simulated

Measured

Control

0

1

2

3

4

5

0 20 40 60 80

R2

02

/20

4M

eH

g

hours

FBN-2 fall

0

1

2

3

4

5

0 20 40 60 80

FBS-3 fall

0

1

2

3

4

5

0 20 40 60 80

hours

OB-2 summer

Summer

0.0E+00

2.0E-04

4.0E-04

6.0E-04

8.0E-04

1.0E-03

kmeth(hrs-1)

OB Summer

0.0E+00

5.0E-04

1.0E-03

1.5E-03

kmeth

(hrs

-1)

FBN Fall

1.4E-6

0.0E+00

4.0E-06

8.0E-06

1.2E-05

1.6E-05

kmeth

(hrs

-1)

FBS Fall

0.0E+00

1.0E-04

2.0E-04

3.0E-04

kmeth

(hrs

-1)

FBN Summer

0.0E+00

5.0E-03

1.0E-02

1.5E-02

2.0E-02

kdemeth

(hrs

-1)

10%

15%

20%

25%

30%

FBN-1 FBN-2 FBN-3 FBN-4 FBN-5

Org

an

ic M

att

er

(% L

OI)

0.0E+00

1.0E-02

2.0E-02

3.0E-02

kdemeth

(hrs

-1)

10%

15%

20%

25%

30%

35%

FBN-1 FBN-2 FBN-3 FBN-4

Org

an

ic M

att

er

(%L

OI)

0.0E+00

4.0E-05

8.0E-05

1.2E-04

kdemeth

(hrs

-1)

0%

5%

10%

15%

20%

25%

FBS-1 FBS-2 FBS-3 FBS-4 FBS-5

Org

an

ic M

att

er

(%L

OI)

0.0E+00

1.0E-02

2.0E-02

3.0E-02

4.0E-02

kdemeth(hrs-1)

0%

5%

10%

15%

20%

OB-1 OB-2 OB-3 OB-4 OB-5

Org

an

ic M

att

er

(% L

OI)

0

2

4

6

8

10

0

50

100

150

200

FBS-1 FBS-2 FBS-3 FBS-4 FBS-5

Me

Hg

(ng

/L)

TH

g (n

g/L

)

FBS Summer (<10 cm water column)

THg

MHg

0

0.1

0.2

0.3

0.4

0

20

40

60

80

100

FBN-1 FBN-2 FBN-3 FBN-4

Me

Hg

(ng

/g)

TH

g (n

g/g

)

FBN Fall

THg

MHg

0

0.1

0.2

0.3

0.4

050

100150200250300

FBS-1 FBS-2 FBS-3 FBS-4 FBS-5

Me

Hg

(ng

/g)

TH

g (n

g/g

)

FBS Fall

THg

MHg

0

0.1

0.2

0.3

0.4

0

20

40

60

80

100

OB-1 OB-2 OB-3 OB-4 OB-5

Me

Hg

(ng

/g)

TH

g (n

g/g

)

OB Summer

THg

MHg

0

2

4

6

8

10

0

5

10

15

20

25

30

OB-1 OB-2 OB-3 OB-4 OB-5

Me

Hg

(ng

/L)

TH

g (n

g/L

)

OB Summer (<10 cm water column)

THg

MHg

0

2

4

6

8

10

0

5

10

15

20

FBN-1 FBN-2 FBN-3 FBN-4

Me

Hg

(ng

/L)

TH

g (n

g/L

)

FBN Fall (>0.6 fractional depth)

THg

MHg

0

2

4

6

8

10

0

5

10

15

20

FBN-1 FBN-2 FBN-3 FBN-4 FBN-5

Me

Hg

(ng

/L)

TH

g (n

g/L

)Water Column

FBN Summer (>0.5 fractional depth)

THg

MHg

0

0.1

0.2

0.3

0.4

0

20

40

60

80

100

FBN-1 FBN-2 FBN-3 FBN-4 FBN-5

Me

Hg

(ng

/g)

TH

g (n

g/g

)

SedimentFBN Summer

THg

MHg

R² = 0.8953

R² = 0.8794

R² = 0.6717

0.0E+00

2.0E-04

4.0E-04

6.0E-04

8.0E-04

1.0E-03

1.2E-03

0% 5% 10% 15% 20% 25% 30% 35% 40%

kmeth

(hr-1

)

Organic matter content (%LOI)

FBN Summer

FBN Fall

OB Summer

• Spatial variability occurs for methyl Hg concentrations and Hg methylation potentials

• Methyl Hg and total Hg concentrations do not correspond to methylation rates

• Initial results tie Hg methylation rates to organic matter content

Summary

FBN Summer - Shallow (<0.7 fractional depth)

0

5

10

15

20

FBN-1 FBN-2 FBN-3 FBN-4 FBN-5

FBN Summer - Deep (>0.8 fractional depth)

0

5

10

15

20

FBN-1 FBN-2 FBN-3 FBN-4 FBN-5

DO (mg/L)

Sulfate (g/L)

Conductivity (mS/cm)/10

FBN Fall - Deep (>0.6 fractional depth)

0

5

10

15

20

FBN-1 FBN-2 FBN-3 FBN-4

FBS Summer <10 cm water column depth

0

5

10

15

20

FBS-1 FBS-2 FBS-3 FBS-4 FBS-5

OB Summer <20 cm water column depth

0

10

20

30

40

OB-1 OB-2 OB-3 OB-4 OB-5