Mallard Island Large Rivers Loading: Monitoring WY 2010 Nicole David Sources, Pathway, and Loading Work Group May 27, 2009 Item #4

SPLWG recognized Delta outflow as potentially significant pathway for contaminants Identified as a high priority information gap Study initiated in 2002 Background Item #4

*Contingency money used (15 samples) Samples Collected Item #4

370,000 cfs Delta Outflow from 12/20/05 to 01/25/06 Item #4

Load Estimates Item #4

Slope 0.22 Slope Low Flow Slope Tidal High Flow - Item #4 SSC – Hg Relationships Influence Loads

PCB Loads and Allocations Item #4

Hg Loads and Allocations Item #4

Sampling Budget Example 5–6 Storms 40 samples for Hg, PCBs, and sediment $35, samples for Hg speciation (HgD, MeHgT, MeHgD, Hg(II)) $10,000 Lab Total $45,000 Field Labor $25,000 Project Management + Reporting $30,000 Overall $100,000 Item #4