River Loads

The “Mallard Island Study”

Nicole David, John Oram, Lester McKee, SFEI

Russ Flegal, UCSC

Sampling Location

Sampling

Hg v SSC (all data)

Influence of Salinity

Suspended Sediment and Hg Loads

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

Organic Contaminants

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 PAHs

FWMC FWMC

6 230

23 350

Project Schedule Summer/Fall 2005: $51k - Write “Final report” for data collected

during WYs 2002, 2003, 2004, and 2005

WY 2006: $60k - Collect wet season “first flush data and update report

WY 2007: $0k - Use RMP contingency funds if necessary to sample a large flood

WY 2008: $0k - Use RMP contingency funds if necessary to sample a large flood

WY 2009: $120k – Sample and report on all floods for the season in addition to reinterpreting the first 8 years of chemical data and 15 years of suspended sediment data