Spatial variation in methylation rates in Farmington and Ogden Bays Ms. Abigail Rudd, Dr. Diego Fernandez, Mr. Greg Carling, Prof. William Johnson University.

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