1 Regional Data Review : What have we learned in eight years? Lester McKee Sources Pathways and Loadings Workgroup Monday December 8 th 2008 San Francisco Estuary Institute Item #4

2 Evolution of knowledge - Hg loads ( ): two loads studies make a large difference (Ref: McKee et al., 2008) Item #4

3 Evolution of knowledge PCB loads ( ): two loads studies make a large difference (Ref: McKee et al., 2008) Item #4

4 How quick do people or instruments need to respond to collect samples? (40 acres) Guadalupe R. (8-10 hrs) Zone 4 Line A (1.5 hrs) (4 acres) City Block (12 min) (Ref: McKee et al., 2003) Item #4 San Francisco Estuary Institute

5 Mercury Load = 6 – 440 kg (Ref: McKee et al., 2005) How many data do we need to estimate loads of a specified accuracy? Mercury Load = – 1,075 kg Mercury Load = 80 – 220 kg Item #4 San Francisco Estuary Institute

6 How many data do we need to estimate loads of a specified accuracy? Item #4 Sampling program running for consecutive years 5-year7-year10-year15-year Exceed 1.5 year return (1,950 cfs) Exceed 2 year return (2,400 cfs) Exceed 3.3 year return (6,900 cfs) Exceed 5 year return (9,200 cfs) Exceed 10 year return (13,600 cfs) San Francisco Estuary Institute

7 Sampling year (s) Estimated long term PCB load (kg) WY 03 only 1.6 WY 04 only 1.9 WY 05 only 0.8 WY 06 only 0.7 WY 03 & WY 04 & WY 05 & WY 03 & 04 & WY 04 & 05 & All years 0.9 How many data do we need to estimate loads of a specified accuracy? Item #4 San Francisco Estuary Institute

8 When within a year should we sample? Alameda Ck. at Niles 10% urban, 1,650 km 2 Colma Ck. at S. San Francisco 57% urban, 41 km 2 Coyote Ck. at Gilroy ??% urban, 275 km 2 Water Discharge Suspended Sediment Load 17% 1% Dry season Wet season Item #4 San Francisco Estuary Institute

9 Grain size and turbidity as a surrogate Item #4 San Francisco Estuary Institute

10 Is it better to measure or estimate concentrations and loads: the Guadalupe River example SS(t/y)HgAgAsCdCrCuNiPbZnPCBDDTChlor-dane Estimated long term Average ( ) 13, , ,2401,0003, Davis et al., 20006,200801,1602,2401,6703,40011,200 KLI, Leatherbarrow et al., , , , ,100 Thomas et al., All loads in kg unless otherwise specified. Item #4 San Francisco Estuary Institute

11 How much do particle Hg concentrations vary between watersheds?  Z4LA < Coyote (non-urb) < Coyote (urb) < San Pedro < Guadalupe R. Item #4 San Francisco Estuary Institute

12 How much do particle PCB concentrations vary between watersheds?  Coyote (non-urb) < Coyote (urb) < Guadalupe R. < Z4LA Item #4 San Francisco Estuary Institute

13 How much do particle PBDE concentrations vary between watersheds?  Coyote (non-urb) < Guadalupe (non-urb) < Coyote (urb) < Guad (urb) < Z4LA Item #4 San Francisco Estuary Institute

14 Which storms need to be studied and does this vary for each POC?  If only storms of 10 cfs had been sampled for Hg, the estimated average particle concentration would be 1.7x higher than sampling 100 cfs  In contrast, the difference would be only 1.4x for PCBs  POC, method, and targeted storms matter Item #4 Z4LA WY 2007 data San Francisco Estuary Institute

15 Which and how many watersheds should be sampled? Area (km 2 ) Area (km 2 ) SS (t/km 2 ) Hg MeHg AgCd Cr Cu Ni Pb Zn PCB PBDE DDT Chlordane Dieldrin Hayward Urban watershed (Z4LA WY 2007) ,4002,5001,8001,80021, Guadalupe River (WY 2004) ,7123,0085,0852,20312, Statistically significant? yesyesmaybenonoyesnoyesnoyesnononomaybeno Export of POC during climatic years with 70% mean annual runoff (units: micrograms per square meter (µg/m 2 ) unless otherwise specified Item #4 San Francisco Estuary Institute

16 Is mercury always particulate and inorganic? (San Pedro, Storm Drain (San Jose)) 65% HgD(%) MeHgT(%) 1% Item #4 San Francisco Estuary Institute

17 Is mercury always particulate and inorganic? (Z4LA, Storm Drain (Hayward)) 36% HgD(%) MeHgT(%) 4% Item #4 San Francisco Estuary Institute