What We Know or What We Think We Know
What We Know or What We Think We Know
Expert Panel Meeting October 21-22, 2008
Closer, But Not There Yet.
So Much Data - So Little Time
Conceptual System Model of Historical Mercury Contamination and Current Exposure Pathway To Fish in the South River, Virginia. Historical Mercury Releases and Deposition in Bed Sediments and Floodplain Soils. Use of Hg catalyst ceased in 1950 but Fugitive Hg Releases and Redistribution Within the River Likely Continued. Mercury Contaminated Surface Water, Sediments, Floodplain Soils
Atmospheric
Hg-Rich FP Soils Erosion of Hg-rich Particles MeHg uptake Biomagnification
Wetland Hydraulic transport of Hg and MeHg
Diffusion of MeHg Groundwater ? Hyporheic Zone ? MeHg Production in Quiescent / Depositional Areas
Base Case RM 20 = Grottoes
RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Water Sediment Microbes Clams Herps Fish Bats Birds (mostly)
From the Plant Site Slow Drip Hypothesis
RM 20 = Grottoes
RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Localized Influence ? 1 g/day
Slow Drip, Hot Spots of Methylation Hypothesis
RM 20 = Grottoes
Islands RM 10 = Crimora
Bed Sediment Flux RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
MAYBE: But Few “Wetlands” per se. BFC data limited.
Inventory Mercury, Erosional Areas Hypothesis
RM 20 = Grottoes
Banks RM 10 = Crimora
Cattle Deposits
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Floodplain, erosion and input from tribs
The “Combo” Hypothesis
RM 20 = Grottoes
Includes LWD. RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Runoff / erosion from FP, tribs
Island Bed Sediment Flux, Gravel Bars, Side Channels
MeHg
Particulates LWD
Bank Attached Active Zone
Bank / Berm
Floodplain Erosion, Cattle Deposits
Low Flow
Erosion and “Packed Column” Effect Bank particulates
3/4 Flow
Pore water, GW intersection,
Low Flow
High Flow LWD, marsh-like areas
Flood
Input from FP erosion, tribs, including particulates
Two Years Later - Bonus Question 1 • If this picture is accurate, what is the mechanism for making the mercury bioavailable ? FP Erosion
3/4 Flow
? Bed Sediment Flux
Two Years Later - Bonus Question 2 • What are the Relative Contributions (source?) from FP Erosion, Bank Erosion, and Bed Sediment Flux ? FP Erosion
3/4 Flow
? Bed Sediment Flux
Sooner, Or, Later
THE ANSWER
Next Steps
EcoStudy Phase 2 • Assemble data for developing a mercury food web model for the riparian / terrestrial zones. - Dr. Newman • Conduct in situ experimental studies – benthic flux chamber – methylation – biological uptake (mesocosm)
Meetings and Publications • Meetings – – – – –
NRDA Meeting – Nov 12 SETAC NA - November 16-20 NRDC Consultation – Nov 18 Bio Summit – Dec 3 International Hg Conf – June
• Publications
SRST Meetings - 2009 • • • •
January – web based April July October
Discussion
Expert Panel Meeting October 21-22, 2008
Closer, But Not There Yet.
So Much Data - So Little Time
Conceptual System Model of Historical Mercury Contamination and Current Exposure Pathway To Fish in the South River, Virginia. Historical Mercury Releases and Deposition in Bed Sediments and Floodplain Soils. Use of Hg catalyst ceased in 1950 but Fugitive Hg Releases and Redistribution Within the River Likely Continued. Mercury Contaminated Surface Water, Sediments, Floodplain Soils
Atmospheric
Hg-Rich FP Soils Erosion of Hg-rich Particles MeHg uptake Biomagnification
Wetland Hydraulic transport of Hg and MeHg
Diffusion of MeHg Groundwater ? Hyporheic Zone ? MeHg Production in Quiescent / Depositional Areas
Base Case RM 20 = Grottoes
RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Water Sediment Microbes Clams Herps Fish Bats Birds (mostly)
From the Plant Site Slow Drip Hypothesis
RM 20 = Grottoes
RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Localized Influence ? 1 g/day
Slow Drip, Hot Spots of Methylation Hypothesis
RM 20 = Grottoes
Islands RM 10 = Crimora
Bed Sediment Flux RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
MAYBE: But Few “Wetlands” per se. BFC data limited.
Inventory Mercury, Erosional Areas Hypothesis
RM 20 = Grottoes
Banks RM 10 = Crimora
Cattle Deposits
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Floodplain, erosion and input from tribs
The “Combo” Hypothesis
RM 20 = Grottoes
Includes LWD. RM 10 = Crimora
RM 5 = Dooms
RM 2 = Hopeman Parkway
RM 0 = Invista Footbridge
Runoff / erosion from FP, tribs
Island Bed Sediment Flux, Gravel Bars, Side Channels
MeHg
Particulates LWD
Bank Attached Active Zone
Bank / Berm
Floodplain Erosion, Cattle Deposits
Low Flow
Erosion and “Packed Column” Effect Bank particulates
3/4 Flow
Pore water, GW intersection,
Low Flow
High Flow LWD, marsh-like areas
Flood
Input from FP erosion, tribs, including particulates
Two Years Later - Bonus Question 1 • If this picture is accurate, what is the mechanism for making the mercury bioavailable ? FP Erosion
3/4 Flow
? Bed Sediment Flux
Two Years Later - Bonus Question 2 • What are the Relative Contributions (source?) from FP Erosion, Bank Erosion, and Bed Sediment Flux ? FP Erosion
3/4 Flow
? Bed Sediment Flux
Sooner, Or, Later
THE ANSWER
Next Steps
EcoStudy Phase 2 • Assemble data for developing a mercury food web model for the riparian / terrestrial zones. - Dr. Newman • Conduct in situ experimental studies – benthic flux chamber – methylation – biological uptake (mesocosm)
Meetings and Publications • Meetings – – – – –
NRDA Meeting – Nov 12 SETAC NA - November 16-20 NRDC Consultation – Nov 18 Bio Summit – Dec 3 International Hg Conf – June
• Publications
SRST Meetings - 2009 • • • •
January – web based April July October
Discussion
