Mercury Transport to San Francisco Bay

through the Sacramento-San

Joaquin River Delta.

Nicole David, Lester J. McKee, Jon E. Leatherbarrow

December 15, 2005

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Sampling Event 2005 January 3 through 6, 2005

Sampling Event 2005

Max dayflow 58,000 cfs

(Max dayflow so far 150,000 cfs)

Sampling Event 2005

Max HgT 13.89 ng/L

Relationship between total Hg and SSC

y = 0.11x + 2.76

R2 = 0.8

0

2

4

6

8

10

12

14

16

0 20 40 60 80 100 120

SSC (mg/L)

Mer

cury

(n

g/L

)

Relationship between total Hg and SSC influenced by salinity

y = 0.12x + 2.54

R2 = 0.8

y = 0.29x - 2.13

R2 = 0.8

0

2

4

6

8

10

12

14

16

0 20 40 60 80 100 120

SSC (mg/L)

Me

rcu

ry (

ng

/L)

EC < 2 mS/cm

EC > 2 mS/cm

Annual Mercury LoadsWater Year Flow (Mm3) Sediment (Mt) Mercury (kg)

1995 51,559 2.58±0.83 399±136

1996 31,436 1.01±0.32 184±62

1997 42,307 2.24±0.72 351±119

1998 53,639 2.42±0.77 389±132

1999 27,805 0.84±0.27 156±53

2000 22,394 0.66±0.21 123±42

2001 8,565 0.26±0.08 52±18

2002 11,303 0.31±0.10 58±20

2003 17,330 0.55±0.17 97±33

2004 18,577 0.64±0.20 110±37

2005* 14,266 0.33±0.11 64±22

Average 27,198 1.08±0.34 180±61

Organic Contaminants

WY 2002 WY 2003 WY 2004TPCBs (pg/L) 200 - 660 320 - 850* 210 - 990TPAHs (ng/L) 16 - 33 12 - 36 5.3 - 28TDDT (pg/L) 342 - 1100 240 - 1550 380 - 760TCHLOR (pg/L) 41 - 111 56 - 178 87 - 190Dieldrin 60 - 120 78 - 250 100 - 170

*four samples collected in May 2003 had TPCB concentrations ranging from 890 – 6700 pg/L

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Preliminary Loading EstimatesLoads are preliminary and were estimated using Regression (REG) and Flow Weighted Mean Concentrations (FWMC). Preliminary estimates of

errors are approximately ± 25%.

REG FWMC REG FWMC REG FWMCWY 2002 6.0 8.2 0.9 1.2 1.8 1.9WY 2003 9.7 13 1.5 1.8 3.0 2.9

Extrapolated to WY 1996 - 2001WY 1995 36 37 4.9 5.3 13 8.7WY 1996 17 23 2.6 3.2 5.3 5.3WY 1997 31 31 4.2 4.4 11 7.1WY 1998 35 39 5.0 5.5 12 9.0WY 1999 15 20 2.3 2.9 4.5 4.7WY 2000 12 16 1.8 2.3 3.5 3.8WY 2001 5.0 6.2 0.7 0.9 1.6 1.4

9 YR AVG 18 21 3 3 6 5

DDT Chlordane Dieldrin PCBs PAHsFWMC FWMC 6 230 23 350

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Project Sampling Schedule

• WY 2006: Collect “first flush” data and sample storm event over 150,000 cfs

• WY 2007: Sample storm event over 150,000 cfs only*

• WY 2008: Sample storm event over 150,000 cfs only*

• WY 2009: Sample all floods

* With RMP contingency money

Project Reporting Schedule

• 2006 Final Report: 2002–2005 data• 2009 Report sampling results and

reinterpret existing data

Item #7