Presentation on theme: "Contaminant Fate WG 5 Year Plan RMP CFWG Meeting September 14, 2007."— Presentation transcript:
Contaminant Fate WG 5 Year Plan RMP CFWG Meeting September 14, 2007
Management Context CFWG addresses linkages between sources and exposure/effects – In Bay transport/partition/transformation/removal processes – Project effects of loads changes (management actions) on processes & ultimately exposure Fate work to date driven by TMDL needs – Mass budget/ conceptual models for priority pollutants, e.g. PCBs, Hg
Previous/Ongoing Work Mass budgets: 1 box models for PCBs, PAH, PBDE; Multibox model for PCBs; TMDLs for Cu/Ni, Hg, PCBs Conceptual models for Cu/Ni, Hg (TetraTech), OCpests, PCBs, dioxins (SFEI), OPpests (PERL), Se (LWA/PERL) Speciation/Partitioning- Cu/Ni- UCSC Bruland/Flegal, Se- Cutter, Hg– Marvin-DiPasquale, Steding/Sedlak, PCBs – Luthy, DDT- USEPA Transformation/degradation- Hg- USGS Marvin-DiPasquale, Cu/Ni- USGS Kuwabara/Topping Biouptake- Se- USGS Luoma/Presser; PCB- Gobas et al.; Hg- UCD Slotton, metals- UCSC Flegal/Luengen, Bruland
Questions to be answered: Are the priorities and questions appropriate ? Have we identified & prioritized the right workplan elements? (Are the budget allocations and timing appropriate?)
Right Priorities and Questions? To date prioritized by focusing on individual contaminants (mirroring TMDLs) – PCBs (via multi-box fate model) (mostly done?) – Hg – in progress Is it time to expand focus (or too early)? – Expanded (generalized) application of sediment/ water fate/ transport models (multi-box) – Other individual contaminants (Se, dioxins)?
#0: PCBs Priorities Are PCBs still a priority for future work, or mostly done for now? – Yes done- already more effort than spent on anything else – No more needed- large uncertainties in many model parameters and assumptions Is multi-box sophisticated enough? – Model resolution outpaces input data? Continued coring Golden Gate export
#1: Hg Priorities Which processes, sources, and pathways contribute disproportionately to food web accumulation of mercury? (Hg Strategy Q2) – SPLWG focus on sources & loads – CFWG focus on process linkages Sed/water transport/mixing, speciation, partitioning, de/methylation, export, burial, uptake* – EEWG focus on food web/effects *CFWG linkage via abiotic factors affecting uptake at primary producer/consumer level
#2: Persistent Particulate Pollutant Priorities What patterns of impairment are forecast for persistent, particle-associated pollutants for major segments and the Estuary as a whole under various management scenarios? – Piggyback off PCBs? – Multi-box application to other pollutants (PBDE>dioxins>Se>PAH>pyreth>pharma>Cu) – [other contaminants may benefit from coring, Golden Gate export estimates work also]
#2: Persistent Particulate Pollutant Priorities To prioritize do we want to continue to mirror TMDLs? – Some efficiency in grouping contaminants, e.g. hydrophobic organics – But responsiveness to stakeholder needs important (RMP mission relevance and timeliness)
Questions Review: Are the priorities and questions appropriate? 0. Are PCB questions sufficiently answered for now? 1. Which processes, sources, and pathways contribute disproportionately to food web accumulation of mercury? 2. What patterns of impairment are forecast for persistent, particle-associated pollutants for major segments and the Estuary as a whole under various management scenarios? Any others, or tweaks to the above?
#0 PCB elements Right elements, right study priorities? None directly planned – Future coring, Ggate export have PCB component but not necessarily their only/central focus. Do we need more PCB specific questions answered? – Degradation rates? Hot spot transport?
#1: Hg Elements Right elements, right study priorities? Already funded 1. Sediment reactive Hg special study (UCSC) Data Integration 1. MeHg mass budget ($ via RMP data integration?)- tool for prioritizing data gaps 2008 top tier SS proposals (CFWG) 1. Hg isotope signatures (2 yr x $75k) 2. Reactive Hg in trib (& air?) sources (1 yr x $60-160k) ~150k placeholder in 2009, 2011 for Hg questions – Identify high leverage sources, processes, pathways
#2: Other Pollutant Elements Right elements, right study priorities? – If not reorder (to match anticipated TMDL timelines?) 1. Screening application of multibox (RMP data integration) 1. Would need loads, literature review for new pollutants 2. Continued coring (alternate years special study? S&T element?) 1. How much is sufficient/ representative? 3. Sediment export – 1. Remote observations (Oram), G Gate, other bridges (Schoellhamer)
Budget and Timeline Alternative distribution? – More distributed coring effort (Maybe) harder on sampling logistics? – 2-3 core sites on RMP S&T surface sampling cruises Easier for analysis (esp. radiodating shorter half life isotopes) – Distributed effort for process studies Pros/cons depends on study design, budget Large influence, large uncertainty = top priority
Elements review: Have we identified and prioritized the right workplan elements? – What directions beyond proposals already made? – MeHg mass budget may help ID gaps? RFPs to get proposals addressing specific elements? – Other pollutant data sufficient for a multibox? E.g. Loads and other details needs higher for multibox
Budget review: Are the budget allocations and timing appropriate? – Commensurate with importance of pollutant questions – In time to inform management actions TMDL schedule to prioritize among pollutants?