1 regulatory update part 2 san francisco bay mercury coordination meeting february 22, 2007 michelle...
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Regulatory UpdatePart 2
San Francisco Bay Mercury Coordination Meeting
February 22, 2007
Michelle Wood (Central Valley Water Board)
Carrie Austin (San Francisco Water Board)
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Outline1. Delta MeHg TMDL & BPA
Background Key Questions
2. State Board’s Scoping Effortsa. Hg Offset Policy for the
Bay-Delta Systemb. Statewide Water Quality Objectives for Mercury
4
The Delta
R
S
F
>1100 mi waterwaysDrains ~1/3 of CA
Reg
ion
2
San Francisco Bay
ReduceCentral Valley
Mercury Outflows by 110 Kg110 Kg
Reg
ion
5
Sacramento
Tracy
StocktonAntioch
Brentwood
5
Delta MeHg TMDL & BPA
TMDL draft staff report (August 2005, revised June 2006) Scientific background
Basin Plan Amendment draft staff report (scientific peer review June-August 2006) Control program
6
Next StepsBoard Workshop in March 2006
Release draft BPA staff report w/ formal comment period
Board Hearing later in 2006
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“The problem with mercury in the Delta’s aquatic ecosystems can be defined as
biotic exposure to methylmercury.”
As stated by Jim Wiener and other researchers in their 2003 Mercury Strategy for the Bay-Delta Ecosystem:
Reduce MeHg exposure to thefish-eating public & wildlife
Delta MeHg Control Program:
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Delta MeHg Control Program1. Revise fish advisories & expand
education & outreach programs to reduce MeHg exposure to the fish-eating public
2. Reduce mercury levelsin Delta fish
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PROPOSED Water Quality Objectives for Delta Fish
0.24 ppm mercury in large predator fish
0.03 ppm mercuryin prey fish California least tern
1 meal/wk
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Average MeHg Levels
in Large TL4 Fish
(mg/kg)[Compare to
Proposed WQO of 0.24 mg/kg]
0.26na
0.50
0.56
0.92
na
0.32
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Control Program
1. Reduce MeHg exposure to the fish eating public & wildlife
2. Reduce mercury levels in Delta fisha.a. Control MeHg sourcesControl MeHg sourcesb. Control total Hg sources
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MeHg Linkage: 350 mm Largemouth Bass & Avg. Annual Water MeHg
y = 20.365x1.6374R2 = 0.91
0.0
0.5
1.0
0.0 0.1 0.2
Aqueous MMHg (ng/l)
350
LMB
Hg
(mg/
kg)
0.24 mg/kg
0.066 ng/l
Mokelumne R.
Central Delta
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Proposed MeHg Implementation Goal
0.06 ng/l in unfiltered ambient water, annual average (~10% margin of safety)
Use goal to establish how much reduction from each source is needed to achieve WQOs
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Delta TMDL: MeHg Sources Within-Delta Sources (~40%) Wetlands (16%) MeHg flux from open water sediments (15%) Waste water treatment plants (4%) Agricultural return flows (3%) Urban runoff (½%)
Tributary Watersheds (~60%)
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Methylmercury Allocations: Implement MeHg Source
Reductions in the Delta & Yolo Bypass by 2030
CapCap MeHg loads from: Atmospheric, dredging, open channel*
ReduceReduce MeHg loads from: Agricultural, WWTPs, stormwater, wetlands & tributaries with discharge > 0.06 ng/l MeHg
MinimizeMinimize MeHg from new sources:(e.g., wetland restoration, water management changes, new WWTP discharges...)
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Phase 1 (2008-2015)Study Period:
Conduct characterization & control studies to evaluate existing sources’ MeHg & TotHg concentrations and loads
GOALS: Address uncertainty in load estimates Develop technically & economically
feasible MeHg management practicesto reduce on-site MeHg production
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Control Program
1. Reduce MeHg exposure to the fish eating public & wildlife
2. Reduce mercury levels in Delta fisha. Control MeHg sourcesb. Control total Hg sources
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Delta TMDL: TotHg Sources
Within-Delta Sources (~3%)Waste water treatment plants (1%)Urban runoff (1%)Atmospheric deposition (1%)
Tributary Watersheds (~97%)
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Inorganic Mercury Limits: Hg Sources in Delta & Tributaries
Downstream of Major Dams CapCap Hg loads from:
Local atmospheric emissions, dredging, flood conveyance, WWTPs, and urban stormwater
ReduceReduce Hg loads by 110 kg from: Cache Creek Settling Basin, American & Feather Rivers & Putah Creek
MinimizeMinimize Hg from new sources Continue upstream MeHg & TotHg evaluations & implement
control actions as part of future TMDLs
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Pilot Mercury Offset Program Phase 1: allow pilot offset projectspilot offset projects to promote early
implementation of MeHg/TotHg reduction projects & to provide information for Phase 2 offset program.
Phase 2: Regional Board considers adoption of an offset program to allow dischargers to offset MeHg and/or TotHg in their discharges by implementing more feasible or cost effective projects elsewhere in the watershed.
The approved offset program must be consistent with any State Board offset policy.
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Outline1. Delta MeHg TMDL & BPA
Background Key Questions
2. Regional / Statewide Effortsa. Hg Offset Program for the San Francisco Bay, Delta &
Tributary Watershedsb. Statewide Water Quality Objectives for Mercury
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Key Question***Highest Priority for Delta & upstream
MeHg control programs***
Can we develop MeHg control actions & management practices
for wetlands, WWTPs& other sources?
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0
1
2
3
4
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65
Facilities
Me
Hg
Co
nc
. (n
g/l)
Preliminary Municipal WWTP MeHg Monitoring Results
26 < 0.05 ng/l
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Other Key Questions: What types of wetlands are
contributing MeHg to the Delta andits tributaries, and how much?
How much TotHg and MeHg does atmospheric deposition contribute to Delta loading?
How does sulfate affect open water MeHg levels in the Delta?
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• Is it possible to design or manage wetlands to reduce wildlife exposure to MeHg?
• Which aquatic species do humans consume and how much?
Other Key Questions:
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• What are the specific mercury effects on key wildlife species in the Delta & its trib watersheds?
• What are the consumption habits of key wildlife species?
• Where do they consume fish? [main channel versus isolated wetlands and Ag drains]
• Which seasons are critical?• Which aquatic species are consumed?
Other Key Questions:The proposed Delta MeHg control program applies
to hydrologically connected waterways.We need a better understanding of the following for
future phases of the control program:
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Outline1. Delta MeHg TMDL & BPA
Background Key Questions
2.2. Regional / Statewide Efforts by State BoardRegional / Statewide Efforts by State Boarda. Hg Offset Program for the San Francisco Bay, Delta &
Tributary Watershedsb. Statewide Water Quality Objectives for Mercury
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Hg OffsetPolicy forthe SF Bay,Delta &Tributary Watersheds
[“Bay-Delta System”]
The red hatching represents the SFBay watershed and Delta source area downstream of major dams.
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Proposed State BoardBay-Delta System Hg Offset Policy
Policy would provide “General Principles” for Regional Water Boards & dischargers to implement offset projects
Policy would not give specific project offset ratios or address pollutant trading
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Statewide Water Quality
Objectivesfor Mercury
Apply to California’s:• Inland waters• Enclosed bays• Estuaries
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State Water Board Considerations Six Objective Alternatives:
MeHg in fish tissue MeHg in water, TotHg in water Fish / water combinations
Uses national average BAFs & MeHg/TotHg translator to convert from concentrations in fish to water
Alternatives vary by: Consumption rates for humans (USEPA default
vs. San Francisco Bay) Species to which WQO would apply (average of
trophic levels vs. top trophic level only)
33
State Board CEQA Scoping for Bay-Delta Offset Policy
& Statewide WQOs: Public Scoping Meeting on Feb 20th
CEQA Scoping comments due Feb 28th
Contact: Tom Kimball or Joanne Cox http://www.waterboards.ca.gov/plnspols/index.html#policies
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Central Valley
Mercury TMDLs
Delta
Clear Lake
Cache Creek Bear Creek
Harley Gulch
American R.
Feather R.
SacramentoRiver
San Joaquin R.
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Water Quality Management Process
Monitoring
Special Discharger Studies
CWA 303(d)
Planning
Assessment
Implementation
Evaluation
Basin Plan- Uses- Objectives- Impl. Program- TMDLs
WDRsWaiversProhibitions
Review- Monitoring Results- Mgmt. Plans
Water QualityImprovement
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Delta Mercury Impairment
High mercury levels in fish
Fish consumption advisories
Federal CWA 303d list
TMDL Program to address impairment
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The Methylmercury Problem Hg is a potent neurotoxicant - impairs nervous,
reproductive, & immune systems in humans & wildlife
Sulfate-reducing bacteria convert mercury to MeHg, the most toxic form of Hg
>90% mercury in top trophic level fish is MeHg
Exposure to MeHg is through consumption of fish & shellfish because of the way MeHg
bioaccumulates
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San Joaquin Subarea Methylmercury Sources
Total Loading: ~478 g/yr
Tributaries77%
OtherInputs23%
Wastewater9%
Agri-culturalLands
5%
Wetlands4%
OpenWater
4% Urban1%
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Yolo Bypass Subarea Methylmercury Sources
Total Loading: ~1,000 g/yr
AgriculturalLands
2%
OpenWater
8%
Other Inputs49%
Wetlands39%Tributaries
51%
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Methylation factors Amount and type of inorganic Hg in sediment Sulfate and pH concentration:
Sulfate in Delta affected by EC and ratio of SJR to Sac R water
% organic matter in sediment Creation of new impoundments increases
MeHg in sediment, water and biota Habitat type, particularly the amount of
seasonally or permanently flooded wetland in a watershed
44
Tributary TotHg Sources & Concerns about Reduction
Millions of kilograms released to waterways by historic mining
Much remains in channels & may be untreatable
Natural erosion will remove some mercury, but it may take centuries to wash the mercury from the waterways
TotHg:MeHg relationship varies by habitat, so how do we develop a safe level for TotHg that would protect the Delta without being overly stringent?
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Interrupt the Methylation Cycle
Control TotHg in watersheds that discharge the most Hg-contaminated sediment
Identify Delta & upstream MeHg sources: Reduce on-site methylation, and/or Reduce TotHg sources that supply the
methylation sources
Shorten time to see fish tissue mercury improvements from centuries to decades
46
Potential Timeline Years 1 to 7: Conduct characterization & control studies; begin TotHg control actions
Year 8: Update MeHg source analyses & allocations, evaluate discharge control programs & offset program, amend Basin Plan as needed
Year 9 to 2030: Implement MeHg control actions
2030 onward: Continued MeHg controls & natural erosion reduces contaminated in-channel sediments
47
What is a Mercury Offset Program?
Voluntary program that enables projects to proceed even if on-site mercury controls are not
feasible. Dischargers could obtain offsets:
1. To help meet their allocations;
2. To allow an increase above their allocations as a result of expansion that would otherwise result in additional mercury loading to the Bay–Delta system; or
3. To initiate a new discharge that would otherwise result in new mercury loading to the Bay–Delta system.
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Mercury Water Quality Objective Alternatives
Option Consumption
rate, g/day
Fish tissue objective, mg/kg
Dissolved MeHg
WQO, ng/L
Total Hg WQO –
rivers, ng/L
1. No action 50
2. USEPA defaults
17.5 0.3, for species mix
0.24 17.1
3. USEPA default
17.5 0.3, for trophic level 4
0.11 7.7
4. SF Bay 32 0.16, for species mix
0.13 9.4
5. SF Bay 32 0.16, for trophic level 4
0.06 4.2
6. SF Bay 32 0.16, water body-specific mix of species
NA NA
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