Trace Metals In SF Bay

1. Trace Metals In SF Bay WIGS Group, UCSC Multiple sources SF Bay one of few estuaries nationwide with temporal data on metals Current WIGS work

2. Complexity of Metal Inputs to SF Bay (Flegal et al, 2005) 1) POTWs and industrial inputs 2) Diagenetic Remobilization: Ag, Co, Ni, Cu, Zn. (Flegal et al., 1996; Rivera-Duarte and Flegal, 1997) 3) Urban Runoff vs Fluvial Inputs 4) Atmospheric deposition(Conaway et al., 2005) 5) Historic Gold Mining (Conaway et al., 2004)

3. “The lack of peer-reviewed scientific reports on current levels of contaminants in those waters over (the past 30 years) precludes statistically valid measures of changes in contaminant levels over the past decade. One exception is the San Francisco Bay Regional Monitoring Program.”

4. Temporal trends in wastewater source loadings of Ag and Pb (Squire et al., 2002) 930 tonnes of trace metals released from POTW of the estuary in 1960, reduced to just 46 tonnes in 1999 Black = South Bay and Gray = North Bay • Clean water Act of 1972 • Closure of a photograph processing plant located in the southern reach in the mid 1980’s • San Francisco’s Oceanside Water Pollution Control Plant rerouted ~ 12% of the total effluent to the Pacific ocean via a 4.5 mile ocean outfall.

5. Pb Isotopes in SF Bay Water (Steding et al., 2000) • Dissolved Pb has not decreased in South Bay • Dissolved Pb is largely composed of 1960-1970s gasoline

6. CurrentWIGS Work • Methods development (Ndung’u et al., 2005) • Effects of Hg on salmonids (Mary) • Hg cycling (Kit) • Mercury speciation and complexation (Frank) • Phytoplankton blooms and metals (Allison)

7. Pronounced Variations in Nutrients and Trace Metals During a Spring Phytoplankton Bloom in San Francisco Bay Allison C. Luengen & A. Russell Flegal University of California, Santa Cruz Summary: • Complexation prevents copper uptake, but not nickel uptake • Bloom decay important for metal cycling • Pb cycling during bloom

8. South SF Bay Characteristics • Predictable phytoplankton bloom in South Bay occurs when water column stratifies in spring(Cloern, 1996) • The phytoplankton bloom depletes nutrients and some trace metals(Beck et al., 2002; Grenz et al., 2000; Luoma et al., 1998) • Metals such as copper are organically complexed, limiting their bioavailability(Buck and Bruland, 2005; Donat et al., 1994 Sunda and Huntsman, 1998)

9. Objectives • Characterize the biogeochemistry of Co, Cu, Ni, Pb, and Zn during a spring bloom • Assess bioavailability of Ni • Effect of bloom decay • Use Principle Components Analysis (PCA) to reduce the data into three factors

10. Rise and Decay of a Bloom

11. 6 0 250 5 0 200 4 0 150 Dissolvedsilicate (µM) 3 0 Dissolved inorganic nitrogen (M) Site 100 2 0 36 32 50 21 1 0 0 0 D a t e Date Nutrients During Bloom: Diagnostic nutrient cycles Nutrient analyses by Steve Hager, USGS

12. Principal Component Analyses

13. Dissolved Cu & Ni During Bloom:Speciation determines uptake

14. Dissolved Ni: Uptake by Phytoplankton • Ni significantly (p<0.00) depleted during bloom • Ni significantly (p<0.00) affected by station

15. Nickel Is Bioavailable • Uptake of Ni consistent with Luoma et al. (1998) field study but different from Beck et al. (2002) lab study. • Why is Ni bioavailable? (Sedlak et al., 1997) • Degradation of EDTA-Ni • Seasonal changes in EDTA-Ni complexation

16. Dissolved Mn & Co During Bloom: Inversely related to bloom Roitz et al. (2002) found remobilization of Mn from sediment following a bloom

17. Dissolved Co: Scavenging & Decay • Increase in dissolved Co during bloom decay NOT due to sediment-water repartitioning • Kd controlled by station in the reduced model (p=0.00024)

18. Dissolved Zn: Scavenging & Decay • Scavenging and bloom decay do significantly (p=0.036 & 0.032, respectively) affect Kd

19. Dissolved Pb During Bloom: Multiple linear regression to assess contribution of individual factors

20. Pb: Rise, Scavenging, & Decay

21. Conclusions • Speciation prevents dissolved Cu uptake, but not dissolved Ni uptake • Decay of the bloom is important for dissolved Mn, Co, Zn • Pb cycling is affected by rise, scavenging, decay

22. USGS: Jim Cloern, Scott Conard, Steve Hager, Amy Little, Cary Lopez, Tara Schraga, and Byron Richards Acknowledgements • calculation WIGS: Frank Black, Kit Conaway, J.R. Flanders, Mari Gilmore, Ana Gonzalez, Sharon Hibdon, Brian Johnson, Fiona Morris, Charley Rankin, Mara Ranville, Genine Scelfo, Hans Schwing COMMITTEE: Ken Bruland, Raphael Kudela, Sam Luoma ANALYTICAL: Rob Franks STATISTICS: Pete Raimondi FUNDING: ETOX Dept, UC Toxics, RMP, C.DELSI