1. Mercury Sources in Local Watersheds: Speciation, Release to Stormwater, and Remaining Questions
Lester McKee
RMP Sources Pathways and Loadings Work Group Chair
San Francisco Estuary Institute
Feb 19th 2008 8

2. RMP Hg Strategy
“…it may be possible to identify specific fractions of total mercury entering the Bay…that contribute disproportionately to accumulation in species of concern…”
Q2. Which processes, sources, and pathways contribute disproportionately to food web accumulation?
Implies we need to understand:
Mass loads – essential for TMDLs
Speciation (availability) of different inputs
Temporal dynamics (within years and between years)
Spatial patterns (Local impacts) 8

3. Outline
Review sources, loads, speciation, and temporal dynamics in Bay Area:
Mining runoff
Urban runoff
Non-urban runoff
First order estimate of methyl-Hg entering the Bay from watersheds. Not ready to do reactive-Hg loads. 8

4. Mining Sources - “True Sources” draining to SF Bay
CEP report (Abu-Saba, 2003)
High Priority (documented discharges, high connectivity to the Bay, obvious habitat threats):
Marsh Creek, Mt Diablo
La Joya, Napa R.
Bella Oaks, Napa R.
Borges, American Canyon Ck.
New Almaden Mines, Guadalupe R. 8

5. Mining Sources (New Almaden, Guadalupe R.) Total Hg Loads
Estimated Long Term Average
( ) = 129 kg
* Year-to-date
Estimated * 8

6. Mining Sources (New Almaden, Guadalupe R.) Wet Season Speciation
Hg-T
(ng/L)
HgD
(%)
MeHgT
Hg-R
Guadalupe River at Hwy 101
MDL -18,700 3*
0.4*
Alamitos Creek at Graystone Lane
1, ,800
1.4*
0.07*
Alamitos Creek at Hacienda
58 – 110,000
McAbee Ck at Little Stone Bridge
,800
Literature Review
McKee et al., 2003
200 - >100,000
Mason and Dean, 2007
,000
(<1)
(<5)
* Weighted concentration
() = authors preference 8

7. Mining Sources (New Almaden, Guadalupe R
Mining Sources (New Almaden, Guadalupe R.) Temporal dynamics (within years)
HgD(%)
15%
MeHgT(%) 2% 8

8. Urban Sources 8 Industrial, railway lines and auto wreckers
Land fills, recycling facilities and transport of recyclable goods
Ongoing uses (dental, batteries, laboratory, PDAs, other)
Watershed surface and channel sediment erosion (natural background)
Gasoline and diesel
Paint
Watershed surface and channel sediment erosion (atmospherically derived)
Atmospheric deposition (on going) 8

9. Urban Sources Estimate 45% of the urban Hg budget is
either derived from historic atmospheric loading
or ongoing atmospheric loading
Watershed surface and channel sediment erosion (atmospherically derived)
Atmospheric deposition (on going) 8

10. Urban Loads (estimates)
Method
Author
HgT
(kg)
Range
“SIMPLE MODEL” (Davis et al., 2000)
and BASMAA bed sediment data
KLI, 2002 96
Reorganization of the Urban Hg Mass
Balance (SFEI and GeoSyntec, 2006)
GeoSyntec and
SFEI, 2006
103
None
and literature concentrations (McKee et al., 2004)
McKee
unpublished
150
10 - 1,028
Estimated urban sediment load (410 M kg)
and urban sediment concentration (0.38 mg/kg)
San Francisco
Bay TMDL
160 8

11. Urban Speciation 8 Hg-T (ng/L) HgD (%) MeHgT Hg-R
Zone 4 Line A, Hayward (Dry year)
15*
1.6*
San Pedro Stormdrain, San Jose
2.3*
0.4*
Airport Pkwy, San Jose 70
9.8
1.4
Coyote Creek, Hwy 237 (rising)
Literature Review
McKee et al., 2003
13 - 1,370
(30-90)
Mason and Dean, 2007
0.8 Wet -
4 Dry
4.8 Wet -
11 Dry
* Weighted concentration
() = authors preference 8

12. Urban Temporal dynamics (within years) (San Pedro, Storm Drain (San Jose)
HgD(%)
65%
MeHgT(%) 1% 8

13. Urban Temporal dynamics (within years) (Z4LA, Storm Drain (Hayward)
36%
HgD(%)
MeHgT(%) 4% 8

14. Non-urban Sources Natural Background (0.08 mg/kg)
Atmospheric Deposition (downwind of urban)
Agriculture uses (pesticides and dairy)
Rural home uses
Watershed surface and channel sediment erosion (natural background)
Watershed surface and channel sediment erosion (atmospherically derived) 8

15. Non-urban Sources Atmospheric Deposition (downwind of urban) 8
Watershed surface and channel sediment erosion (atmospherically derived) 8

16. Non-urban Loads 8 Method Author HgT (kg) Range
Estimated urban sediment load (410 M kg)
and urban sediment concentration (0.38 mg/kg)
San Francisco
Bay TMDL 25
None
“SIMPLE MODEL” (Davis et al., 2000)
and BASMAA bed sediment data
KLI, 2002 27
7 - 37
and literature concentrations (McKee et al., 2004)
McKee
unpublished 32
5 – 57
Reorganization of the Urban Hg Mass
Balance (SFEI and GeoSyntec, 2006)
GeoSyntec and
SFEI, 2006 52 8

17. Non-urban Speciation 8 Hg-T (ng/L) HgD (%) MeHgT Hg-R
Coyote Creek, Hwy 237,
San Jose (falling stage)
Literature Review
McKee et al., 2003
1 - 90
Mason and Dean, 2007
0 - 88
<
0.05 – 56
(1-10)*
(15)
* Dependant on amount of wetland
() = authors preference 8

18. Non-urban Temporal dynamics (within years)
No information locally
Review by Mason and Dean (2007) summarizes much of the recent literature:
Higher % HgD associated with low SSC streams and summer base flow
Seasonality of % MeHgT less clear but can correlate with flow, SSC, and HgT in some systems. Influenced by %wetland and DOC in some systems 8

19. First Order Estimate of MeHgT loads
Land
Use
Method
Reference
MeHg
(kg)
Range
Mine
Field data collected over four years in the
Guadalupe River at Hwy 101
McKee et
al., 2006
0.5
Urb
“SIMPLE MODEL”, local and literature
concentrations (Mason and Dean, 2007)
McKee
unpublished
0.4
Applying a ratio of MeHg to the urban loads estimates for the Bay Area
1.5
Non-
urb
Applying a ratio of MeHg to the non-urban
loads estimates for the Bay Area
1.25
0.001 – 29*
*Biggest uncertainty 8

20. Summary
New
A picture of total and methyl mercury variation in Bay Area watersheds is emerging
Loads Speciation Seasonality Q2
Non-urban runoff is potentially a large source of MeHg and Hg-R in both wet and dry weather flow
No local data (Suggest Napa, Walnut, Alameda, or Coyote)
Urban dry weather flows high in MeHg and Hg-R as a % of HgT, but no loads data to determine impact
Will sample Z4LA this early summer (n = 9 samples)
Bay Hg Basin Plan Amendment and MRP call for monitoring 8

21. References
Mason R., and Dean, D., WERF’s bioavailability project: Research update. The Claremont Resort & Spa, Berkeley, California, December 4-5, 2007.
McKee, L., Leatherbarrow, J., Eads, R., and Freeman, L., Concentrations and loads of PCBs, OC pesticides, and mercury associated with suspended sediments in the lower Guadalupe River, San Jose, California. A Technical Report of the Regional Watershed Program: SFEI Contribution #86. San Francisco Estuary Institute, Oakland, CA. 79pp. 8

22. Acknowledgements SFEI field and data management staff
Sources Pathways and Loading Work Group
Funding from:
RMP
CEP
SCVWD, SCVURPPP, USACE
Water Board
Moss Landing Marine Laboratories 8