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Presented by Peter Mitchell

Habitat, Chemistry, Community Structure, and Mercury in Benthics and Blacknose Dace Deerfield River Watershed, Massachusetts and Vermont. Presented by Peter Mitchell. Study Objectives. Assess habitat and water chemistry conditions

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Presented by Peter Mitchell

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  1. Habitat, Chemistry, Community Structure, and Mercury in Benthics and Blacknose Dace Deerfield River Watershed, Massachusetts and Vermont Presented by Peter Mitchell

  2. Study Objectives • Assess habitat and water chemistry conditions • Collect and identify stream macroinvertebrates and blacknose dace for the purposes of community assessment, and tissue analysis • Investigate the variability in mercury concentrations in macroinvertebrates and blacknose dace using standard physical, chemical, and biological variables

  3. Mercury (Hg) • Most toxic of all non-radioactive heavy metals • No known function in any human biological process • Ingestion is most prevalent toxicant pathway • Exposure may result in: chromosomal breakage, CNS damage, birth defects, death • May be aerially deposited to areas of no point source discharge • Anthropogenic sources: waste and sludge incineration, sewage treatment plant operation, fossil fuel combustion

  4. Forms of Environmental Hg • Elemental (metallic) mercury Hg0 • Divalent (mercuric) mercury Hg++ • Methylmercury CH3Hg+ • Dimethylmercury (CH3)2Hg

  5. Upwind emission and proximal deposition Aquatic habitats rich in organic matter CPOM and FPOM processing and transport Diminished pH and ANC Elevated temperature Dissolved oxygen flux Microbial activity Community structure Number of trophic levels Conditions Affecting Mercury

  6. Drainage Area (km2) by Type

  7. Width and depth Mean bank angle Substrate type Gradient Canopy coverage Aspect and sinuosity Watershed area Number of unimpounded 1st, 2nd, and 3rd order streams Number of unimpounded ponds and wetlands Upstream and abutting landuse Habitat Assessment MeasuresStream Reach Measure Watershed Measure

  8. Chemical Measures • Air Temperature (oC) • Water Temperature (oC) • Conductivity (µmhos) • pH • Acid Neutralizing Capacity (ANC) • Dissolved Oxygen (DO) • Total Organic Carbon (TOC) • Discharge (cms)

  9. Taxa Richness Eveness Diversity Functional Feeding Groups Tolerance Dominance Habit Mass Macroinvertebrate Community Metrics

  10. Tissue Analysis • Sample Type……..Homogenized, Freeze-Dried • Sample Type..……Liquid Organic Extraction • Lab……………….Xral (Toronto, Canada) • Detection Limits…5ppb (Total and Organic) • Tissue Standards…Three (DOLT-1, DOLT-2, TORT-2) • Accuracy…………95%

  11. Wetlands and Ponds

  12. Rapid Bioassessment Protocol Habitat Scores

  13. Water Chemistry Results

  14. Total and Organic Mercury:Macroinvertebrates

  15. Wetland / Pond Ratioand Mercury

  16. Total Organic Carbonand Mercury

  17. EPTand Mercury

  18. Scraper / Filterer Ratioand Mercury

  19. Multiple Regression:EPT and TOC over Total Mercury

  20. Multiple Regression:EPT, TOC, Scraper / Filterer, and Wetland / Pond over Organic Mercury

  21. Hg in Blacknose Dace and Benthics

  22. Biomagnification Factors

  23. BMFs:Organic Hg / Size of blacknose dace

  24. Implications for Higher Trophic Levels

  25. Increase riparian vegetative zone Decrease organic inputs Increase variety of discharge Set limits on mercury fuel content Dam removal Sewage treatment plant design Incinerator design Remediation National Watershed

  26. US Fuel Consumption for Electrical Generation 2002

  27. Future US Energy Sources for Electrical Generation

  28. Elemental Mercury (Hg0) Vapors

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