Transcript 4_McKee_Hg_loading - San Francisco Estuary Institute

Comparative Analysis of Loads of
Mercury in Coyote Creek and
Guadalupe River
Lester McKee
RMP SPLWG Chair
San Francisco Estuary Institute
[email protected]
Acknowledgements and Data Sources
Coyote Creek
• USGS discharge
– WY 1999 – 2006 (ongoing)
•
•
•
USGS suspended sediment
– WY 2005
– WY 2006
Regional Board TMDL laboratory
funding ($10k)
– WY 2005 PCB, PBDE, HgT, SSC,
organic carbon
Data
– SFEI field team able to grab 7
samples during wading stage only
during breaks from Guadalupe R.
sampling
Guadalupe River
• USGS discharge
– WY 1929 – 2006 (ongoing)
•
USGS/SFEI suspended sediment
– WY 2003 – 2006 (ongoing)
•
Funding
– WY 2003 CEP
– WY 2004 CEP / RMP
– WY 2005 RMP / SCVWD / USACE /
SCVURPPP
Data
– HgT, HgD, MeHgT, MeHgD,
Bedload HgT
•
Land Use Comparisons
Area
(below
Dams)
Industrial
Commercial
Residential
Open/
Agricultural
Coyote Ck.
(km2)
335
15
16
83
222
Percentage (%)
100
4
5
25
66
Guadalupe R.
(km2)
236
30
30
137
38
Percentage (%)
100
13
13
58
16
Field Locations
Coyote Ck. at Hwy 237
USGS 11172175
Area: 826 km2
Guadalupe R. at Hwy 101
USGS 11169026
Area: 414 km2
Guadalupe R.
Coyote Ck.
Methods
Sampling Location
USGS Gage Shelter
Results – Coyote Creek
Sample Number
Date / time
Suspended
Sediment
(mg/L)
Total
Mercury
(ng/L)
-
40
CC40
12/7/04 9:05
CC70
12/27/04 12:22
51
11
CC80
12/31/04 14:51
228
54
CC90
1/7/05 8:38
77
21
CC91
1/7/05 16:35
110
39
CC92
1/9/05 11:55
70
18
CC100
1/11/05 17:04
338
59
CC100 Dup
1/11/05 17:06
335
57
Total Mercury v Suspended Sediment
(All data)
Total Mercury (ng/L)
70
y = 0.21x
R2 = 0.75
60
50
40
30
20
10
0
0
100
200
300
Suspended Sediment (mg/L)
400
Total Mercury v Suspended Sediment
(Runoff from Upper and Lower Watershed)
70
y = 0.19x
2
R = 0.84
Total Mercury (ng/L)
60
y = 0.32x
50
2
R = 0.87
40
30
20
Lower
Upper
10
0
0
100
200
300
Suspended Sediment (mg/L)
400
Loads Calculation Methods
(WY 2005)
• USGS 15 minute discharge
• USGS 15 minute SSC estimates from GCLASS based on rating
relationships between flow and about 100 real measurements of
SSC
• Regression between instantaneous SSC and Total Mercury
concentrations
– All data
– Separate regressions for water derived from Lower and Upper
watershed
Maximum Daily and Flood Loads
Total Mercury
Wet Season (Oct 2004 - Apr 2005) (kg)
2.5
Maximum Daily (2/15/05)
Load (kg)
Load (% wet season)
0.23
9
Largest Flood (2/15/05 14:30)
Load (kg)
Load (% wet season)
0.28
12
Why so little during the largest flood?
1200
Flow (cfs)
1000
800
600
400
200
0
Oct-04
Nov-04
Dec-04
Jan-05
Date
Feb-05
Mar-05
Apr-05
Results – Monthly Loads
2004
Oct
2005
Nov Dec Jan
Feb
Mar
Apr Total
Flow (Mm3)
3.3
1.3
4.9
6.9 10.3 13.1 7.5
47
Total Mercury (kg)
0.4 0.02
0.5
0.2
2.5
0.7
0.6 0.1
Coyote Ck. at Hwy 237 (cfs)
Estimated Average - Methods
Measured
Estimated
y = 0.7211x
500
R = 0.9206
2
400
300
200
100
0
0
150
200
400
600
Guadalupe R. at Hwy 101 (cfs)
Average = 41 Mm3
100
50
Water Year
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
0
1971
Flow (Mm 3)
200
600
800
Estimated Average Coyote Loads
• Using the range in flow experienced from WY 1971 to
WY 2006 we estimate the following:
Flow (Mm3)
Total Mercury
Total Mercury
(Estimated using
(Estimated using
separate regressions) A single regression)
(kg)
(kg)
Minimum
2.0
0.001
0.001
Maximum
173.9
55
44
40.6
7
6
Average
Coyote Creek versus Guadalupe River
Coyote Creek
HgT
(ng/L)
11-58
HgT
(mg/kg)
Load
(kg)
Export
(µg/m2/yr)
0.17-0.36
7
(0.001 - 55)
20
Guadalupe River
HgT
(ng/L)
HgT
(mg/kg)
Load
(kg)
140
DL - 18,673 0.41 - 95 (0.03 - 1,000)
Export
(µg/m2/yr)
600
Particle Concentrations
Total Mercury (ng/L)
Coyote Ck, Guadalupe R. and Sacramento R.
10,000
Guadalupe River at Highway 101 (Mining water)
1,000
Guadalupe River at Highway 101 (Urban water)
Coyote Creek at Highway 237 (Urban water)
100
Sacramento River at Mallard Island (Floods >150,000 cfs)
10
Coyote Creek at Highway 237 (Non-urban water)
Sacramento River at Mallard Island (Floods <150,000 cfs)
1
10
100
1000
Suspended Sediment (mg/L)
Applicable Management
Questions
B. Loads of mercury and methylmercury
• Are current estimates about loading to San Francisco
Bay from watersheds, wastewater treatment facilities,
and atmosphere valid?
• What is the contribution of atmospheric deposition to
urban storm water?
Applicable Management
Questions
C. Processes of mercury methylation
• What is the relative bioavailability of mercury entering
the Bay from various loading sources (e.g.,
wastewater treatment facilities, atmosphere, urban
runoff, tributaries, newly eroded historic sediments,
etc)?
Applicable Management
Questions
D. Given what we currently understand about
processes, loads, and impacts (Sections A, B, and
C), what are the management implications?
• Given that rivers, creeks, and storm drains discharge
methyl mercury, what can be done to manage
production in the watershed and urban environments,
and to manage downstream impacts as it passes
through wetlands to the Bay margin and Bay?