# Presentation: 125098

## Assessment of Hg in Sediment, Water, and Biota of VT and NH LakesA Collaborative REMAP Project

- Neil Kamman, VTDEC
- New Hampshire Dep’t Environmental Services
- Syracuse University
- USEPA Region 1 and USEPA - ORD

## VT / NH REMAP-Hg Project Collaborators

- NHDES
- VTDEC
- Syracuse University
- Dartmouth College
- Sci. Museum of Minnesota
- US Fish and Wildlife Service
- VT Dep’t of Fish and Wildlife
- BioDiversity Research Institute

## Project inception

- In 1997, we knew very little about Hg levels in lakes of northern New England, outside of Maine.
- Application of sampling and analytical methods for trace metal work were just becoming available outside of academic realm.
- EPA Region 1 developed a strong interest in having a complete picture of Hg contamination across the entire region.

## Core program goals for the period 1998 to 2000	

- Use USEPA “EMAP” approach to:
- Identify the physico-chemical identity(ies) and hypothesized trophic Hg transfer pathway of lakes which pose a risk of Hg contamination to people and wildlife;
- Model Hg signal in lakes outside the study set, which can identify target waters for further fish/avian assessments;
- Model air deposition using MDN / UMAQL network
- Understand the historical accretion patterns of Hg into lakes as a tool to understand potential gains given reduced Hg deposition.

## VT / NH REMAP-Hg ProjectStudy design:

- 90+ lake geographically randomized sample
- Hg and meHg collections in water, sediment, plankton, fish, avian piscivores, sediment cores
- Hg-clean methods used for all Hg collections
- Water by CVAFS
- Mud and Biota by CVAA
- Dataset describing current Hg conditions,
- Design permits geographic analyses, and
- Dataset ripe for opportunistic analyses (e.g. mining).

## VT / NH REMAP-Hg Project Parameter list

- Water: Hg, meHg, nutrients, DOC and acid-base chemistry, physicochemical measures
- Sediment: Hg, meHg , solids and organic content
- Macrozooplankton – Hg, bulk >200*u* fraction
- Yellow Perch in two size classes, Hg and meHg
- Upper trophic level piscivore tissue Hg (e.g., loons, kingfisher): blood, feather, egg

## Study lake locations

*1998*
*1999*

## VT / NH REMAP-Hg ProjectIn the field

- Pontoon-craft

## VT / NH REMAP-Hg ProjectIn the field

- Considerations for clean water collections

## VT / NH REMAP-Hg ProjectIn the field

- Clean, undisturbed overlying
- water

- Perfect sediment-H2O
- interface

- Core laminae

## VT / NH REMAP-Hg ProjectIn the field

## VT / NH REMAP-Hg ProjectFindings:				

- VT / NH REMAP-Hg ProjectFindings:

- Cumulative frequency distributions
- Hg and lake trophic status
- Hg and land-use
- Water chemistry and methylation
- Predicting tissue Hg
- Piscivore Hg risk assessment
- Air deposition models
- Historic and current Hg accumulations

## VT / NH REMAP-Hg ProjectFindings:				Water Hg

**VT / NH REMAP-Hg Project****Findings:****	****	****	****	****Water Hg**

## VT / NH REMAP-Hg ProjectFindings:				Sediment Hg

**VT / NH REMAP-Hg Project****Findings:****	****	****	****	****Sediment Hg**

*Sediment methylHg ranges from <0.0006 ug g**-1** to 0.021 ng g**-1*

## VT / NH REMAP-Hg ProjectFindings:				Tissue Hg

**VT / NH REMAP-Hg Project****Findings:****	****	****	****	****Tissue Hg**

## VT / NH REMAP-Hg ProjectFindings					Hg in Yellow Perch

- Fish in acidic lakes have elevated Hg in their tissue:

## VT / NH REMAP-Hg ProjectHg and Lake Trophic Status			

- VT / NH REMAP-Hg ProjectHg and Lake Trophic Status

- Bloom Dilution
- Pickhardt et al. PNAS 2002.
- More algae means less Hg per unit algae
- So lakes of elevated trophic status should show less Hg in the plankton, and therefore less bioaccumulation.

## VT / NH REMAP-Hg ProjectLake trophic status		

## VT / NH REMAP-Hg ProjectHg and Land Use			

- VT / NH REMAP-Hg ProjectHg and Land Use

- Do forested and wetland rich watersheds deliver more Hg? Literature says they should.
- What about developed watersheds?

## VT / NH REMAP-Hg ProjectLand use correlations (Spearman)		

|  | % Forested | % Ag. | % Wetland & water | % Dev. | E911 |
| --- | --- | --- | --- | --- | --- |
| HgT | ns | ns | ns | ns | -0.32 |
| meHg | 0.228 | ns | ns | ns | -0.198 |
| Sed. HgT | ns | -0.33 | ns | ns | -0.53 |
| Perch fillet HgT | 0.38 | -0.216 | ns | -0.41 | -0.239 |

## VT / NH REMAP-Hg Project       Water chemistry influences

*PC1****: +Cond, +ANC, +pH, +SO4, +CL-*

*There is too much heterogeneity of lake types and factors to yield satisfactory ‘univariate’ relationships. *
*Joint ‘multivariate’ distributions provide insight into how the interaction of factors controls Hg.*

## Modeling compliance with tissue criterion

## Modeling compliance with tissue criterion

## VT / NH REMAP-Hg ProjectCumulative Risk Index based on Hg in Loon Blood

## History of Hg Accumulation:Atmospheric Hg Deposition

**Can wet Hg deposition be modeled given existing MDN/UMAQL network?**
**What about dry Hg deposition?**

## VT / NH REMAP-Hg Project       Atmospheric deposition

## VT / NH REMAP-Hg Project

**Is the Hg flux rate to VT and NH lake sediments presently increasing or decreasing?**
**Can we then infer changes in the atmospheric deposition rate?**

## VT / NH REMAP-Hg ProjectFindings			HgT Fluxes (ug . m-2 . yr-1)

- Note the synchrony of flux increase and decrease

**Increasing Basin Area / Lake Area**

## VT / NH REMAP-Hg Project        Synopsis:

- Hg concentrations in VT and NH lakes range widely. [ ]’s are greater in NH, and in lake hypolimnia.
- Yellow perch fillets vary w/ age and size, and age-correction most accurately captures variation in Hg accumulation rates across lakes.
- Hg, meHg, and tissue Hg all vary with trophic status.  Eutrophic and dystrophic lakes have higher meHg, but only dystrophic lakes show higher tissue Hg.

## MethylHg varies significantly w/ numerous water chemistry parameters.  The way these parameters inter-relate is important to understanding in which lakes meHg is more readily produced. 

For VT-NH lakes, the likelihood that yellow perch tissues will violate current criteria can reasonably be modeled using simple parameters.

- For VT-NH lakes, the likelihood that yellow perch tissues will violate current criteria can reasonably be modeled using simple parameters.

**VT / NH REMAP-Hg Project  ****Synopsis:**

## VT / NH REMAP-Hg Project Pubs:

- Paleolimnology
*Atmos. Environ*. 2003.
- Water and Tissue Chemistry and Statistics:
*Env. Tox. Chem.* 2004.
- Modeling, air deposition:
*Ecotoxicology in prep*.
- Modeling: Air+watersheds+in-lake interactions
- Ongoing w/ EPA-ORD

## How does this all get used??

- TMDL’s
- Air dep maps and by-lake estimates provide one estimate of critical loads – these dep maps are in preparation for all of NE presently
- Additional modeling can and will follow w/ these data
- Env. Indicators:
- CDF’s provide reproducible,  statistically valid estimates of region-wide contamination signals
- Paleo profiles provide reproducible, statistically quantified and landscape-integrated estimates of deposition, both presently and historically
- NERC Hg project for NE US and SE Canada.
- EPA Regional Modeling Project