Lake Champlain Research Consortium

Toxic Substances Research Priorities

9-24-2004

 

Participants:

Neil Kamman, VTDEC

Doug Burnham, VTDEC

Miranda Lescaze, LCBP

Mark Malchoff, NY Sea Grant/PSU

 

Angela Shambaugh, VTDEC

Jamie Shanley, USGS

Mary Watzin, UVM

 

 

This document presents a series of overarching questions concerning toxic contaminants in Lake Champlain and its watershed. Bullet statements of prior progress are provided, along with priority actions.  A separate summary of the highest-priority items is provided, along with frameworks for two interdisciplinary research programs addressing cyanobacteria and associated cyanotoxins, and the bioaccumulation of mercury in the lake.  This listing was developed by a collaborative workgroup formed from invited participants with expertise in the issues of toxic contamination in Lake Champlain.

 

Contents:

1. What is the importance of various sources of toxic substances?. 2

Progress – to 1999. 2

Progress – to 2004. 2

Priorities beyond 2004. 2

2. What processes control the fate of toxic substances in the basin?. 3

Progress to 1999. 3

Progress to 2004. 3

Priorities. 3

3. How important are existing sites in the lake where contamination has already been documented?. 4

Progress to 1999. 4

Progress to 2004. 4

Priorities. 4

4. What are the long-term impacts of toxic substances on the Lake Champlain ecosystem?. 5

Progress to 1999. 5

Progress to 2004. 5

Priorities. 5

5. What are the future contaminants of concern?. 6

Progress to 2004. 6

Priorities. 6

6. How do we communicate results in such a manner as to foster action to reduce contaminant loads?  7

Progress to 2004. 7

Priorities. 7

7. List of top priorities established by the workgroup. 8

8. Interdisciplinary research program ideas. 9

Cyanotoxins: 9

Mercury Food Web Interactions. 10

 


1. What is the importance of various sources of toxic substances?

Progress – to 1999

Continued efforts by Keeler et al. to understand role of atmospheric Hg sources (monitoring of Hg in precipitation since 1992… longest of its kind in the world).

 

Work by Fuller et al. in Cumberland Bay and Main Lake to determine patterns of PCB occurrence.

 

Analysis by Rowell et al. of the NYDEC of toxic constituents in urban runoff in 18 tributaries; found occasional PCBs, frequent PAHs and hits for pesticides DDT and chlordane in Burlington area.

 

Progress – to 2004

Monitoring of mercury in tributary discharges by Shanley et al.

 

Multimedia characterizations of mercury in inland lakes of the LC basin (VT) by Kamman et al.

 

Source attributions of atmospheric Hg by Keeler et al (in review presently) and VTDEC.

 

Development of preliminary mass balance model of mercury in L.C. by Gao et al.

 

Stormwater toxics assessment by UVM in Burlington Bay (Watzin et al.), including both chemical analyses and toxicity tests.

 

Priorities beyond 2004

Continue analysis of atmospheric component of contaminant loading to the lake.

 

Continue to refine source attribution for Hg and other contaminants (partly being accomplished by 2004-2005 NOAA/LCRC funding to the LC Mercury Mass Balance project).

 

Consider use of Underhill site for new contaminants in addition to mercury: e.g., dioxins/furans (see atmospherics section of this document).

 

Evaluate contaminant concentrations in stormwater outside of Chittenden County.

 

Continue refinement of LC Mass Balance model for Hg.

 

Continue and expand monitoring of cyanobacterial blooms and associated cyanotoxin levels, and identify if the occurrence of cyanotoxins can be predicted from readily available data/factors.  Determine if cyanotoxins affect other components of the planktonic food web. Continue to determine whether water suppliers that depend on LC waters are producing finished waters with levels of cyanotoxins above levels of concern.  Develop a public reporting system to identify locations and times when cyanotoxins are likely to be present. Cyanotoxins are arguably the top-priority in terms of toxins in the lake presently.

 

2. What processes control the fate of toxic substances in the basin?

Progress to 1999

Efforts by Shanley to understand transport of Hg through upland watersheds.

 

On-going assessment of Kamman et al. of relationship between drainage basin parameters and Hg fates in lakes.

 

Evaluation by Watzin et al. of uptake of trace contaminants by zebra mussels.

 

Progress to 2004

Continued work on Hg discharge from upland watersheds by  Shanley et al.  Publication of this material is forthcoming in 2005.

 

Completion of Kamman et al. studies of Hg in inland lakes, and publication, tech-transfer, and publicity of results.

 

Completion of studies of Hg deposition to high-elevation portions of the LC Basin (Lawson et al.), transport from upland and agricultural streams (Rinehart et al.).

 

2003 NOAA workshop on atmospheric research and publication of an atmospheric contaminants research plan.

 

Priorities

Fish must be assessed for tissue PBDE concentrations.  Lake Champlain is woefully under-characterized in regards to this new contaminant.

 

Assess food web transport of Hg by linking food web and toxic substances research (being addressed for Hg preliminarily by 2004-2005 NOAA/LCRC funding).

 

Continue research on effects of zebra mussels on contaminant dynamics – specifically, might ZM’s play a role in transferring toxic contaminants in areas of rapid colonization.  By changing particle distribution between the water column and the sediments, and by attracting large densities of benthos that are favored fish food (e.g., amphipods) do zebra mussels make contaminants more available to food webs? 

 

Foster collaboration between research on toxic substances, hydrodynamics and atmospherics and other disciplines. 

 

Measure Hg concentrations in lamprey tissue.  Arguably, lamprey could be exploited as a commercial species for sale in Europe (where lamprey are considered good eatin’).

 

3. How important are existing sites in the lake where contamination has already been documented?

Progress to 1999

Cumberland Bay assessment complete; cleanup in progress

 

Tetra Tech Inc. performed follow up work in 1997 in Inner Burlington Harbor; found generally lower levels

of contaminants in sediments than previous studies suggested, but noted substantial toxicity to Hyallela sp.  in sediment toxicity assays.

 

Additional analysis of Inner Harbor sediments in 1996 yielded conflicting results, with trace metals higher

than in 1993 and 1994

 

Analysis of mysids and rainbow smelt from Outer Malletts Bay for arsenic and nickel indicated no

bioaccumulation of these elements.  Toxicity in this site was subsequently attributed to Mn bioavailability due to resuspension of this element during periods of hypolimnetic anoxia.

 

Burlington Bay project planned to measure sublethal indicators of stress among fish and zooplankton collected from Inner Burlington Harbor.

 

Incorporate toxics characterizations into monitoring portions of the adaptive stormwater management programs.

 

Progress to 2004

Mix of contaminants and additivity of contaminants in stormwater in Burlington Bay documented.  Potential toxicity is heavily influenced by the organic matter in the stormwater.

 

Development of preliminary evidence that toxins in stormwater can inhibit algal growth in full-strength stormwater.  Implications of this for eutrophic response is not yet clear.

 

Priorities

Additional work needed on changing mix of contamination in stormwater and the ecological effects. 

 

Changes in sediment toxic concentrations should be assessed on a periodic basis, perhaps every 10 years, at select long-term sediment chemistry monitoring sites.  It has been 10 years since the initial assessments. 

 

Effects of chronic, low-level contamination in sediments on biota needs additional assessment. 

 

Investigate incorporating toxin monitoring into cormorants.  During summer, cormorants are faithful to specific feeding areas of the lake that may be as far as 20 miles from nesting areas.  Moreover, cormorant control efforts have technicians on nesting islands harvesting/destroying eggs.  In loons, eggs provide a critical depuration pathway for Hg and other contaminants, and are reflective of contaminants acquired in the recent time period preceding egg-laying.  Avain toxicology expertise is available within New England to implement such an assessment.

 

4. What are the long-term impacts of toxic substances on the Lake Champlain ecosystem?

Progress to 1999

Development of historic records of trace elements in Burlington Bay, Outer Mallets Bay, Cumberland Bay, and selected other sites in the Main Lake. 

 

Facey’s work on rock bass from north and south Inner Burlington Harbor to compare 1999 data on

macrophage aggregates and liver parameters to 1992 data on same species.

 

Progress to 2004

~400 fish collected by VTDFW for toxics analysis (Hg and organics but not PBDE’s).

 

First assessment of historical deposition of mercury to Lake Champlain sediments – north Main Lake, Malletts Bay, Port Henry section (Kamman and Engstrom)…others have cored the lake sediments for mercury, but these cores were never dated to derive Hg sedimentation rate profiles.

 

Research from MN indicates that lakes with high levels of Hg contamination have a higher incidence of fish with biomarkers of endocrine disruption.  This effect should be evaluated for Lake Champlain.

 

Priorities

Do toxicity tests in areas known to be historically contaminated indicate improving conditions?

 

Determine if levels of mercury and PCBs carried by walleye and trout are sufficiently high to cause

sublethal effects, particularly on sensitive life stages.

 

Determine if fish PCB levels have declined following the toxic substances reductions

 

Identify indicators or biomarkers of unacceptable levels of toxic contamination in fish

 

Assess chronic effects of existing point source discharges where permits might indicate a potential problem

 

Use existing and developing databases to try and determine if mercury concentrations in Lake Champlain Basin fishes has declined coincident with declines in regional emissions of mercury.

 

5. What are the future contaminants of concern?

Progress to 2004

Preliminary assessment of Atrazine concentrations in Missisquoi River and Miss. Bay.

 

Initiation of cyanobacterial toxin assessments by UVM and SUNY.

 

Limited initial measurement of pharmaceutical contaminants in Lake Champlain Basin WWTF’s by USEPA (results not available as of this writing).

Priorities

Develop, jointly with LCBP, a plan for a lakewide re-characterization of toxics, with emphasis on new generation toxic contaminants such as known endocrine disruptors, PBDE’s, plasticizers, antibiotics, and also emphasizing current use herbicides and pesticides.  This assessment should focus on new generation contaminants in water and sediment, re-measure a subset of the 1992 sediment sites to determine if changes have occurred (see above), and be designed in a geographically and statistically unbiased manner. One component of the assessment should focus on river mouth wetlands (the estuaries of Lake Champlain).

 

This assessment should also identify potential wastewater discharges of endocrine disrupting contaminants by screening WWTP discharges for a target list of contaminants.  Toxicity tests should be done either in concert, or after this screening. 

 

There are some good strong “holo-tox” sceening methods that are being used in Europe and in other parts of the country.  We should look at these for fresh ideas about the best mix of chemistry, toxicity testing, looking for biomarkers, etc. 

 


6. How do we communicate results in such a manner as to foster action to reduce contaminant loads?

Progress to 2004

Publication of the 1999 A.G.U. Lake Champlain monograph “Lake Champlain in Transition” and preparation of a second AGU monograph

 

LCBP indicators project by Watzin et al is an important project in terms of communicating results

Priorities

Develop strategy to package results of work done 1992-2004 and transfer this to the public in a user friendly and positive way that will generate momentum for local cleanup, and for regional and national pollutant control.  Success in the field of toxics characterization should be based not on research publications, but rather by the transfer of the project’s findings into the citizen community, in a way that the information can be used to press for environmental benefit.  There is a perception in and outside of Vermont that Lake Champlain is polluted and should not be used.  In reality, only certain segments of the lake are affected at various times.  A public information campaign is necessary so that people realize the unmet potential of the lake.  One important message is that there are reasons to be concerned, but there are also things that individuals can do to improve the lake.  Success stories should be highlighted. The Hubbard Brook Research Foundation’s ScienceLinks Program is one example where top-level researchers have combined the results of their collective works to develop synthetic manuscripts and reports, which are then used in a media campaign aimed at providing the scientific findings in a clear and concise fashion targeted for maximum public exposure, including the failures and successes.  The ScienceLinks publications on acid rain and nitrogen, and their associated media planning,  have yielded concrete legislative proposals at the national level.  As Champlain is the nations sixth largest lake, a similar approach to Hubbard Brook’s could well result in pollution control actions at the national level, while greatly improving the public image of the lake as well.

 

 

 

 


 

7. List of top priorities established by the workgroup.

Priority

Priority statement

1

Develop, jointly with LCBP, a plan for a lakewide re-characterization of toxics, with emphasis on new generation toxic contaminants such as known endocrine disruptors, PBDE’s, plasticizers, antibiotics, and also emphasizing current use herbicides and pesticides.  This assessment should focus on new generation contaminants in water and sediment, re-measure a subset of the 1992 sediment sites to determine if changes have occurred (see above), and be designed in a geographically and statistically unbiased manner. One component of the assessment should focus on river mouth wetlands (the estuaries of Lake Champlain).

 

2

Continue and expand monitoring of cyanobacterial blooms and associated cyanotoxin levels, and identify if the occurrence of cyanotoxins can be predicted from readily available data/factors.  Determine if cyanotoxins affect other components of the planktonic food web. Continue to determine whether water suppliers that depend on LC waters are producing finished waters with levels of cyanotoxins above levels of concern.  Develop a public reporting system to identify locations and times when cyanotoxins are likely to be present. Cyanotoxins are arguably the top-priority in terms of toxins in the lake presently.

 

3

Assess food web transport of Hg by linking food web and toxic substances research (being addressed for Hg preliminarily by 2004-2005 NOAA/LCRC funding).

 

4

Fish must be assessed for tissue PBDE concentrations.  Lake Champlain is woefully under-characterized in regards to this new contaminant.

 

5

Determine if levels of mercury and PCBs carried by walleye and trout are sufficiently high to cause sublethal effects, particularly on sensitive life stages.

 


8. Interdisciplinary research program ideas.

Cyanotoxins:

Disciplineŕ

Toxins

Nutrients

Public Health

Research questions

-What is the distribution of cyanotoxins in LC

 

-What is the toxicological effect of cyanotoxins on biota in the lake

 

 

How are changing nutrient levels fostering cyanobacterial growth?

 

What is the likely role of resuspended nutrients in fueling cyanobacterial blooms?

 

Can climactic factors predict the likelihood of cyanobacterial blooms?

-What is the potential toxicological effect of cyanotoxins on bathers at varying ages?

 

-What is the likely exposure of bathers to cyanotoxins?

-Are there interactive effects of  current use herbicides and nutrients that favor cyanobacterial dominance within algal communities?

Research actions:

Continue to monitor algal communities and cyanotoxins.

 

Conduct assays of cyanotoxicity on indicator organisms

 

Perform comparative field measurements cyanotoxicity biomarkers in biota across a gradient of cyanotoxins concentrations

Continue monitoring of nutrient levels lakewide

 

Conduct assays to determine the effect of  nutrient  and herbicide concentrations on cyanobacteria growth

 

Develop data that can be used in a trend analysis to determine if cyanotoxins are changing in response to changing nutrient concentrations/loadings.

 

Review relevant literature on cyanotoxicity at ambient exposure levels

 

Catalogue levels of swimming use in sites that are subject to cyanobacterial blooms

Results:

Development of a model that predicts the likelihood that blooms conditions will be sufficient to produce toxins in concentrations of concern for swimmers,other direct contact users, or aquatic biota, given factors related to nutrients, climate, and (perhaps) herbicide concentrations. This model can be run under a variety of nutrient loading scenarios, including reduction targets established by the Lake Champlain TMDL.

 

 


Mercury Food Web Interactions.

Disciplineŕ

Atmospherics

Toxins

Public Health

Nutrients

Questions

What are the trajectories for storms that deliver Hg “slugs” to the Lake Champlain Basin?

 

What is the likely source apportionment for High Hg deposition events?

 

With what simultaneously-deposited contaminants is Hg associated for wet and dry deposition?

 

What is the current status of Hg in fishes of  Lake Champlain

 

In which segments of the lake is Hg more or less efficiently transported through the food web

 

Is the methylHg loading to the lake attributable to wetlands at major rivermouth deltas, or is it produced throughout tributary watersheds?

 

Does Hg and methylHg ( and simultaneously available metlas/contaminants) at current ambient levels result in chronic sublethal effects to fish?

 

Are there sources of Hg to the Lake Champlain Basin that are not atmospheric (WWTF, dental discharges)?

Has Hg in fishes declined in recent years?

 

Are consumption advisories sufficiently protective for subsistence consumers of Lake Champlain fish?

 

 

Are there areas of Lake Champlain that display algal bloom biodilution of methylHg?

 

What are the threshold algal densities beyond which bloom dilution is expected?

 

Will Hg in fishes in eutrophic segments of Lake Champlain increase as nutrient loading is controlled?

 

Actions

Continue atmospheric monitoring of Hg at Underhill, VT, including transitioning to a locally-based

 

Pair source apportionment analyses (using PMF) with back-trajectory analyses to establish likely source areas for Hg deposition events

Continue processing samples colleted in Lake Champlain from 2003 and 2004.

 

Implement Lake Champlain Mass Hg Balance Project – 2005 (N. Gao et al.)

 

Continue USGS monitoring of Hg and methylHg levels in the lakes “estuaries.”

 

Conduct bioassays of Hg and other contaminants in admixtures to assess chronic toxicity of multiple contaminants on organisms that are endemic to Lake Champlain. 

 

Measure Hg in WWTF discharges.

 

 

Result

Comprehensive Hg and other contaminant control strategy for point sources within the Basin.  Baseline of information from which to measure improvement following implementation of pollutant controls.  Additional information that may be used to support emissions reductions of Hg and other contaminants at the national and international level.