# Presentation: 495381

## 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
- 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

## 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

## Forms of Environmental Hg

- Elemental (metallic) mercury	Hg0
- Divalent (mercuric) mercury	Hg++
- Methylmercury 			CH3Hg+
- Dimethylmercury 			(CH3)2Hg

## Conditions Affecting Mercury

- 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

## Slide 6

## Slide 7

## Slide 8

## Drainage Area (km2) by Type

## Habitat Assessment MeasuresStream Reach Measure	       Watershed Measure

- 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

##                           Chemical Measures

- Air Temperature (oC)
- Water Temperature (oC)
- Conductivity (μmhos)
- pH
- Acid Neutralizing Capacity (ANC)
- Dissolved Oxygen (DO)
- Total Organic Carbon (TOC)
- Discharge (cms)

## Macroinvertebrate Community Metrics

- Taxa Richness
- Eveness
- Diversity
- Functional Feeding Groups

- Tolerance
- Dominance
- Habit
- Mass

## 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%

## Wetlands and Ponds

## Rapid Bioassessment Protocol Habitat Scores

## Water Chemistry Results

## Total and Organic Mercury:Macroinvertebrates

## Wetland / Pond Ratioand Mercury

## Total Organic Carbonand Mercury

## EPTand Mercury

## Scraper / Filterer Ratioand Mercury

## Multiple Regression:EPT and TOC over Total Mercury

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

## Hg in Blacknose Dace and Benthics

## Biomagnification Factors

## BMFs:Organic Hg /  Size of blacknose dace

## Implications for Higher Trophic Levels

## Remediation

- 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

- _Watershed_

- _National_

## US Fuel Consumption for Electrical Generation 2002

## Future US Energy Sources for Electrical Generation

## Elemental Mercury (Hg0) Vapors