RMP Coring Study Wrapup

1. RMP Coring Study Wrapup RMP CFWG Meeting June 2010

2. Core- What Is It Good For? • Bay pollutant inventory • erosional time bombs? • Model validation • Conceptual &/or mechanistic • Model development • Empirical, mechanistic, hybrid • Can recalibrate, but better up front

3. RMP/CEP Sites (Bay) • Representative • inventory, sedimentation • 3 sites Central Bay, 2 sites each other segments • Preference to RMP repeat stations

4. Distribution of Sites (Wetland) • Loading history • Depositional zones • 1 site each segment • Pt Edith Martinez • Wildcat Richmond • Damon Sl. Oakland • Greco Island • Coyote Creek • +1 watershed site • Alviso Marina

5. Bay Hg Results < 1960 < 1960 < 1960 < 1960 < 1960 < 1960 < 1960 < 1960

6. Conceptual Model Fits in Bay • Radiodating fits bathymetric history • North Bay erosive (137Cs near surface) • Central, South Bay ~neutral, or erosive • Lower South Bay depositional • Contamination fits sediment history • Top core sections ~ RMP surface sediments • Lower contamination in deepest sections • pre industrial background • Contaminants elevated in industrial period • Metals ~uniform downcore, PCBs higher nearer surface

7. Wetland Hg Results < 1960 < 1960 < 1960 < 1960 < 1960

8. Wetland Results • Radiodating fits sea level rise • All areas net depositional (2-3mm/year) • Lower South Bay subsided, higher deposition • Contamination fits sediment history • Top core sections ~ RMP surface sediments • Usually lower contamination in deepest sections • pre industrial background • Contaminants elevated in industrial period • Sharper/higher peaks than in Bay cores • Watershed (Alviso) site ambiguous • Rapid deposition, but where is Hg peak?

9. Core- What Was It Good For? • Bay pollutant inventory • Few time bombs other than LSB, wetlands • Model validation • Results fit conceptual model of • mostly terrestrial/watershed sources • In-Bay dispersion, dilution • Model development • Some data for next generation of models

10. Immediate Next Steps • Close of review comment period • Revisions, final report July 5 Near-term additions • Dioxins in Bay cores (4-5 sections x 11 cores) for exposure risk $57k • Need wetlands if info on loading history needed • Any need for more PBDEs? • Only 3 wetlands. Remaining wetlands (+Bay) would provide contrast to older legacy • Lab currently has samples, will discard

11. Longer Term Next Steps? • Better than before, but enough? • N = 11 from RMP/CEP + 2-5 from USGS • N depends on which analytes • OK for Baywide scale but few for segment specific modeling (N=2) • Nothing in shallow waters (<2m) • Time frame needed • Before new models need data • Resolution needed • What scale are we actually planning to act on?

12. Logistical Lessons • Waiting for preliminary radiodating slowed study • Created backlog at RMP laboratories (3+ years equivalent of S&T samples) 17 cores x 10 sections/core = 170 samples • Total cost $300k+, hard to reduce, especially analytical costs (1 site = 10 samples x X analytes)

13. Incremental Efforts • 2 Bay sites (optionally +1 wetland?) in one Bay segment per year • Gravity/hammer core in Bay, Livingstone (piston) core in wetland • Analyze up to 10 sections at ~10cm (skipping) intervals Cost ~$50k for Bay cores, ~$75 w/ wetland (PCBs, Hg, metals, TOC, grainsize)

14. +/- Incremental Approach • Few sites, more often (e.g. 2 per segment, different ones yearly) + Better workload for labs (20+ vs 100+ samples at once) + Costs better spread for RMP + Can get info on segments w/ greatest data needs first • Long time to get full Baywide set • Other details decided depending on program needs

15. Back to Basic Questions • Do we need more cores? • Probably, especially if we plan sub-segment scale models • All at once, or a few at a time? • A few at a time is easier for many logistical and budget reasons • When, where, how many? • Best early/before models finished, random/ representative of areas modeled, # samples depending on model questions, scale