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Spatial and temporal patterns in food web accumulation of Hg

Spatial and temporal patterns in food web accumulation of Hg. Project Update RMP Exposure and Effects Work Group May 12, 2008. Workplan: Specific questions to address. Where is mercury entering the Bay food web?

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Spatial and temporal patterns in food web accumulation of Hg

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  1. Spatial and temporal patterns in food web accumulation of Hg Project Update RMP Exposure and Effects Work Group May 12, 2008 Draft data - do not cite or quote

  2. Workplan: Specific questions to address • Where is mercury entering the Bay food web? • What habitats, conditions, or factors help to identify hotspots of food web accumulation in Bay margins? • Are there interannual trends in MeHg bioaccumulation resulting from wetland and margin restoration activities? • What are the best biomonitoring tools for characterizing hotspots of MeHg bioaccumulation? Draft data - do not cite or quote

  3. General approach • Spatial analysis • Stratified random design • Identify hotspots based on conceptual model • Seasonal trend evaluation • Interannual trend detection • Field sampling for Hg isotopes and for DGT study Draft data - do not cite or quote

  4. Allocation of effort • Total of 62 sampling events per year to evaluate spatial, seasonal, and interannual patterns Draft data - do not cite or quote

  5. Spatial survey design - hypothesis testing Draft data – do not cite or quote

  6. Spatial survey sites chosen probabilistically Same GRTS method as Status and Trends Program What types of conditions Bay-wide higher Hg Stratified sampling scheme Even if all our hypotheses are wrong, we are still characterizing conditions and identifying hotspots Bay-wide Draft data – do not cite or quote

  7. How separating different site types? Draft data - do not cite or quote

  8. Map of areas to be sampled • GIS based on morphology, size, depth • Strata 1: • Open Shorelines • -Strata 2: • Enclosed areas and creeks Draft data – do not cite or quote

  9. Identifying Hg source areas Draft data - do not cite or quote

  10. Source site selection • Mining sources • Creeks draining probable source mines • POTW discharges • Feedback from RB NPDES Permitting Staff • Creeks draining urban/industrial areas • Feedback from BASMAA • Industrial areas with high sediment THg • Total of about 50 sites Draft data - do not cite or quote

  11. Wetland site selection Draft data - do not cite or quote

  12. Wetland site selection • Oversight by Josh Collins and Letitia Grenier • Based on GRTS sampling performed for SBMP and CRAM • Stratified based on: • relative wetland elevation and age • Is wetland hypothesized to be high or low in bioavailable Hg Draft data – do not cite or quote

  13. Results of site selection Draft data - do not cite or quote

  14. Non-wetland site selection Years 1 - 3 Draft data – do not cite or quote

  15. Wetland site selection Years 1-3 Draft data – do not cite or quote

  16. Source site selection Years 1-3 Draft data – do not cite or quote

  17. All sites Year One Draft data – do not cite or quote

  18. Source Sites Year One Draft data – do not cite or quote

  19. Enclosed vs. Open shoreline Year One Draft data – do not cite or quote

  20. All sites Year Two (does not include wetlands) Draft data – do not cite or quote

  21. Coordination and Collaboration • University of Michigan – RMP Hg stable isotope study (Joel Blum, Gretchen Gehrke) • Hg isotope sites characterize specific sources • Urban runoff, mining, waste water, atmospheric deposition • Sites will be chosen from small fish source sites after probabilistic site selection is complete • Sediment Hg and isotope analysis Draft data - do not cite or quote

  22. Coordination and Collaboration • Trent University – Diffusive Gradient in Thinfilm devices (Holger Hintelmann) • Just completing analyses of the pilot study data (2007) • Year 1 - validation • 15 small fish sites varying in chemistry and expected bioaccumulation • Will overlap with mercury isotope sites • Year 2 – process studies • Source sites of interest including fishless locations • Gradient studies • Likely include SPL sites (e.g., Z4LA) • Report available February 2010 • Addition of water column DOC as correlate Draft data - do not cite or quote

  23. Discussion points • How select sites for DGT and Hg isotope in year one Draft data - do not cite or quote

  24. END OF TALK • REST IS ANCILLARY MATERIAL IN EVENT OF DISCUSSION Draft data - do not cite or quote

  25. Draft data – do not cite or quote

  26. Draft data - do not cite or quote Draft data – do not cite or quote

  27. Sediment MeHg may be correlated with topsmelt Hg • Topsmelt 2006 data • RMP and Calfed • sediment data within 1.5 km disk of fish • R2 = 0.61 Draft data - do not cite or quote

  28. Trend analysis – a multiple station BACI design Draft data – do not cite or quote

  29. Trend Sampling Locations Hamilton Benicia Park China Camp Control Point Isabel Impact (Restoration) Oakland Middle Harbor Candlestick Point Eden Landing Bird Island/ Steinberger Slough Newark Slough Alviso Slough Draft data – do not cite or quote

  30. Trend Sampling Locations Hamilton Benicia Park China Camp Control Point Isabel Impact (Restoration) Oakland Middle Harbor Candlestick Point Eden Landing Bird Island/ Steinberger Slough Newark Slough Alviso Slough Draft data – do not cite or quote

  31. Monthly sampling locations Additional North Bay Station Sampled by USFWS Martin Luther King Shoreline Draft data – do not cite or quote

  32. MLK Shoreline Location Draft data – do not cite or quote

  33. Collection of additional parameters • Aimed at better understanding mechanisms for spatial variation in bioavailable Hg • GIS spatial parameters • Sediment parameters Draft data - do not cite or quote

  34. Sediment parameters Sediment parameters: redox, TON, grain size, total and methyl Hg Samples at subset of 20 Sites Draft data - do not cite or quote

  35. Sediment MeHg: < 1 ng/g 1 – 2 ng/g > 2 ng/g Draft data - do not cite or quote

  36. Annual monitoring of trend stations

  37. Draft data - do not cite or quote

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