figure 1. location of the palo alto sampling station in south san francisco bay
TRANSCRIPT
Figure 1. Location of the Palo Alto sampling station in South San Francisco Bay.
J M M J S N94
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Time (months)
0
5
10
15
20
25
30
Sal
inity
(pa
rts
per
thou
sand
)Salinity
1994 1995 1996 1997 1998 1999 2000 2001
Figure 2. Water column salinity at Palo Alto from 1994 through 2001.
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Figure 3. Percent silt/clay, iron and aluminum in sediments at Palo Alto from 1994 through 2001.
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Time (months)
0.00
1.50
3.00
4.50
6.00
7.50
9.00
10.50
12.00
Alu
min
um &
Iron
(pe
rcen
t dry
wei
ght)
0
20
40
60
80
100
Per
cent
<10
0 m
Percent aluminum, iron and silt/clay in sediment
Fe Al Silt/Clay
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 4. Near-total extraction concentrations of chromium, vanadium, and nickel in sediments at Palo Alto from 1994 through 2001.
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Time (months)
0
20
40
60
80
100
120
140
160
180
200
Cr,
V, a
nd N
i in
sedi
men
t (g
/g)
Chromium, vanadium, and nickel in sediment
1996 1997 1998 19991994 1995 2000 2001
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Figure 5. Near-total and acid-extractable copper concentrations in sediments at Palo Alto from 1977 through 2001.
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Time (months)
0
10
20
30
40
50
60
70
80
Cu - Near-total extr
200
280
360C
u in
sed
imen
t - N
ear-
tota
l ext
ract
(g/
g)
0
20
40
60
80
100
Cu
in s
edim
ent -
HC
l ext
ract
(g/
g)
Cu - HCl extract
Copper in sediment
1995 1996 1997 1998 20011994 1999 2000
ERM=270ppm
ERL=34ppm
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Figure 6. Concentrations of near-total and acid-extractable zinc in sediments at Palo Alto from 1994 through 2001.
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Time (months)
0
50
100
150
200
Zn -Near-total ext
400
450
500
Zn
in s
edim
ent
- N
ear-
tota
l ext
ract
(g/
g)
0
20
40
60
80
100
Zn
in s
edim
ent
- H
Cl e
xtra
ct (
g/g)
Zn - HCl extract
Zinc in sediment
1995 1996 1997 1998 20011994 1999 2000
ERM=410ppm
ERL=150ppm
Regional Background=75ppm
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Figure 7. Acid-extractable silver concentrations in sediments at Palo Alto from 1990 through 2001. Extractions were conducted with 0.6 N Hydrochloric acid.
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Time (months)
0.00
0.20
0.40
0.60
0.80
1.003
4
Silv
er in
sed
imen
t (g
/g)Silver in Sediment
HCl extract
Regional Background
ERL=1.0ppm
ERM=3.7ppm
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Figure 8. Total extraction concentrations of cadmium in sediments at Palo Alto from 1994 through 1999.
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Time (months)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Cad
miu
m in
sed
imen
t (g
/g)
Cadmium in sediment
1995 1997 199919961994 1998
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Figure 9. Concentrations of selenium and mercury in sediments at Palo Alto from 1994 through 2001.
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Time (months)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sel
eniu
m &
Mer
cury
in s
edim
ent (
g/g
) Selenium & Mercury in sediment
Hg Se
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 10. Annual mean concentrations of copper in the clam Macoma balthica at Palo Alto from 1977 through 2001. Error bars denote the standard error of the mean (SEM).
77 79 81 83 85 87 89 91 93 95 97 99 01
Time (Years)
0
50
100
150
200
250
300
350
400
Cop
per
in c
lam
tis
sue
(g
/g)
Annual Mean Copper in Macoma balthica
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Figure 11. Annual mean concentrations of silver in the clam Macoma balthica at Palo Alto from 1977 through 2001. Error bars denote the standard error of the mean (SEM).
77 79 81 83 85 87 89 91 93 95 97 99 01
Time (Years)
0
20
40
60
80
100
120
140
Silv
er in
cla
m t
issu
e (g
/g)
Annual Mean Silver in Macoma balthica
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Figure 12. Concentrations of copper in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0
30
60
90
120
150
Cop
per
in c
lam
tiss
ue (g
/g)
Copper in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 13. Concentrations of silver in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0
3
6
9
12
15
Silv
er in
cla
m ti
ssue
(g
/g)
Silver in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 14. Concentrations of zinc in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0
100
200
300
400
500
600
700
Zin
c in
cla
m ti
ssue
(g
/g)Zinc in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 15. Concentrations of chromium in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0
3
6
9
12
Chr
omiu
m in
cla
m ti
ssue
(g
/g)
Chromium in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 16. Concentrations of nickel in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0
3
6
9
12
15
Nic
kel i
n c
lam
tis
sue
(g
/g)
Nickel in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 17. Concentrations of selenium in sediments and clams at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Sel
eniu
m in
sed
imen
t (g
/g)
0
1
2
3
4
5
6
7
8
9
10
Sel
eniu
m in
cla
m ti
ssue
(g
/g)
Selenium in sediment & clams
Se-sed Se-clam
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 18. Concentrations of mercury in clams (Macoma balthica) at Palo Alto from 1994 through 2001. Error bars denote the standard error of the mean (SEM).
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Time (months)
0.00
0.20
0.40
0.60
0.80
1.00
Mer
cury
in c
lam
tiss
ue (
g/g)
Mercury in clams
1994 1995 1996 1997 1998 1999 2000 2001
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Figure 19. Weight of Macoma balthica of 25 mm shell length (condition index) as determined between 1988 through 2001 at Palo Alto.
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Time (months)
0
50
100
150
200
250
300
Tis
sue
wei
ght i
n m
g (2
5 m
m c
lam
)Condition Index
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
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Figure 20. Correlation of maximum condition index in Macoma balthica vs. maximum copper concentrations in the months preceding the determination of maximum condition. Data from Palo Alto and San Jose sites for the period from 1990 through 2001.
0 100 200Copper in clam tissue (g/g)
0
100
200
300C
ondi
tion
Inde
x of
cla
ms
(mg
in 2
5 m
m c
lam
)
Max Cu vs. Max CI: PA & SJ
1990 - 19 1999-200 2001
No Cu effect on CI
Cu reduces CI
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