1. Mercury Dissolution Studies in Soil Columns as a Function of pe
Matthew Fox
Dr. S. Grimberg

2. Objectives
Predict the effect of pe on abiotic/biotic Hg transformations in sediments
Net effect of pe on Hg in controlled pe conditions:
Dissolved Hg
Transformed Hg
Transported Hg

3. Soil Composition Aerobic Metabolism: Oxidation of organic matter
Denitrification:
Sulfate
Reducing
Conditions:
Sulfate reducing bacteria
causing Hg Methylation
Methanogenesis:
*Modified from Dr. Kim Shulz: Limnology/RedoxReac2.jpg

4. Abiotic and Biotic Column Conditions
Anaerobic:
Sulfur couple
Variable
column
Anaerobic:
Nitrogen couple
Aerobic
Eh Range (mV)
The columns
model the soil zones
within the watershed
200 to 800
50 to 750
-650 to -200

5. Column Setup Measure pH/pe before and after column
Outflow will be into a sealed container to reduce contamination
Many samples for HgT and a few
samples for MeHg
pH/ORP meter
N2 Purge
+ Disp.
Pump
Ready for Hg analysis
Media solution
Flow through cell
Column

6. Experimental Stages Quartz sand: Quartz sand w/ HgS: Soil: Soil w/HgS:
vary pe, DOC in abiotic environment
Obtain stable reproducible results.
Quartz sand w/ HgS:
vary pe, DOC in abiotic and biotic environment
Soil:
vary pe, DOC in biotic environment
Soil w/HgS: 1. 2. 3. 4.

7. Expected Relative Output from Columns

8. Accomplished to Date Collected Soil samples next to Sunday Lake
Collected Influent and Effluent water/DOC samples, filtered through 5.0 and 0.45 mm, storing frozen
Experimental setup for two columns with automatic data logging capabilities
Determined the mV effect of quartz sand for the non-buffered systems:
Couples: NH4+ / NO3- and HS- / SO42-
Couples with trace metal media
Nitrogen Couple stability with trace metal and Phosphorus buffer

9. Infrared Digital Orthoquad Sp 2003
water
soil

11. Future Plans
Testing under varied pe, DOC conditions while recording mV, pH and determining HgT and less often MeHg
quartz sand with HgS
soil
soil with HgS