Presentation on theme: "BACKGROUND AND STATUS of RMP SEDIMENT STUDIES RMP EEWG MEETING September 6, 2007."— Presentation transcript:
BACKGROUND AND STATUS of RMP SEDIMENT STUDIES RMP EEWG MEETING September 6, 2007
RMP SEDIMENT COMPONENTS 1. Status and Trends Sediment Characteristics (grain-size, TOC, etc.) Sediment Toxicity (Eohaustorius and elutriate – larval bivalves) 2.Pilot and Special Studies 3.Collaborative Studies
RMP PILOT AND SPECIAL STUDIES Benthic Pilot Study (Thompson et al., 2000) Development of Toxicity Tests (Weston, 1995) Wetlands Pilot Study (Collins et al. 1995) Sediment Work Group / Atlas (Thompson et al. 1999) Episodic Toxicity / TIE studies (Anderson et al. 2007) Influence of chem. & phys. factors (Melwani, Thompson, 2007) on benthos
COLLABORATIVE STUDIED Local Effects Monitoring Program (BACWA, 1994-1996) CisNet (1999-2001, EPA / UCD) EMAP SF Estuary Surveys(EPA, NOAA) State Board BioCriteria (SWRCB, SCCWRP) SQO 2005-present (SWRCB, SCCWRP) - Several publications - Delta Sediment Survey(DWR) Non-Indigenous Benthos (EPA, 2000) Long Term Sediment Management Study (ACOE, BCDC) Delta Dredged-Sediment Reuse Study (CALFED, RB 5)
CONCEPTUAL MODELS Mechanisms of Exposure and Effects - Sediment Atlas, 1999 Toxicity Dose – Response - Anderson et al., 2007 Benthic Response to Disturbance - Thompson et al., 2004
WHAT HAVE WE LEARNED? SEDIMENT CONTAMINATION Sediments may contain elevated levels of several contaminants. - As, Cu, Zn, Ni - DDT, PAHs, Chlordanes - Mixtures Highest concentrations in muddy sediments near margins, mouths of tributaries, Ports, BPTCP hot- spots.
WHAT HAVE WE LEARNED? SEDIMENT TOXICITY Sediment toxicity is widespread and persistent in San Francisco Estuary Different results for different tests More toxicity in wet season, and at margins Toxicity has been associated with: - Chlordanes - Mixtures - Cu ions in pore water, Suisun Bay - Non-polar organics, Redwood Ck. - Pyrethroids in some tributaries, Delta
WHAT HAVE WE LEARNED? BENTHOS Assemblage distribution and composition - have we sampled all of them? Assemblages distribution changes in response to fresh water inflows Species composition and abundances within assemblages may change in response to contamination, sediment type, salinity,different in different parts of the Estuary. Causes mostly unknown. Associated with specific mixtures, interaction of factors
TMDLs in place that include sediments as sources SQO will be Implemented in next few years. RMP role: continue to provide information to RB and participants. Stressor ID: Must know cause and effect to effectively implement TMDLs, source controls. MANAGEMENT CONTEXT
INFORMATION NEEDS AND NEXT STEPS Stressor Identification for SQOs Identify contaminants that cause toxicity, benthic impacts SQO Phase II, Delta sampling Include benthic sampling in S & T Revised Long-Term Sediment Studies Plan for RMP
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