Mallard Island Large Rivers Loading: Monitoring WY 2010

Nicole David

Sources, Pathway, and Loading Work Group

May 27, 2009

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• SPLWG recognized Delta outflow as potentially significant pathway for contaminants

• Identified as a high priority information gap

• Study initiated in 2002

BackgroundItem #4

Water Year Hg PCBs PAHs oc-Pest PBDEs Se2002 10 10 10 10 - -2003 23 23 23 23 - -2004 31 31 31 31 - -2005 10 10 10 - 10 102006* 25 25 25 - 25 25Total 99 99 99 64 35 35

*Contingency money used (15 samples)

Samples CollectedItem #4

0

100,000

200,000

300,000

400,000

12/20/05 12/30/05 1/9/06 1/19/06

Dates

Dis

char

ge

in c

fs

370,000 cfs

Delta Outflow from 12/20/05 to 01/25/06Item #4

Load Estimates

Water Year Flow (Mm3) Sediment (Mt) Hg (kg) PBDE (kg) PCBs2002 11,000 0.3 61 - 3.32003 17,000 0.5 100 - 202004 19,000 0.6 130 11 4.12005 19,000 0.4 86 9.5 8.02006 50,000 2.0 470 12.0 18

Average 29,000 1.2 260 11 13

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Slope 0.22

Slope 0.11 - Low Flow

Slope 0.29 - Tidal

High Flow -

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SSC – Hg Relationships

Influence Loads

PCB Loads and AllocationsItem #4

Hg Loads and AllocationsItem #4

Sampling Budget Example5–6 Storms40 samples for Hg, PCBs, and sediment$35,00020 samples for Hg speciation (HgD, MeHgT, MeHgD, Hg(II))$10,000

Lab Total $45,000 Field Labor $25,000Project Management + Reporting $30,000

Overall $100,000

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