Grantee Research Project Results
Final Report: Chemical and Biological Control of Mercury Cycling in Upland, Wetland and Lake Ecosystems in the Northeastern U.S.
EPA Grant Number: R827633Title: Chemical and Biological Control of Mercury Cycling in Upland, Wetland and Lake Ecosystems in the Northeastern U.S.
Investigators: Driscoll, Charles T. , Yavitt, Joseph , Newton, Robert , Munson, Ronald
Institution: Syracuse University , Tetra Tech Inc. , Cornell University , Smith College
Current Institution: Syracuse University , Cornell University , Smith College , Tetra Tech Inc.
EPA Project Officer: Packard, Benjamin H
Project Period: November 1, 1999 through October 31, 2002 (Extended to October 31, 2003)
Project Amount: $786,680
RFA: Mercury: Transport and Fate through a Watershed (1999) RFA Text | Recipients Lists
Research Category: Watersheds , Heavy Metal Contamination of Soil/Water , Water , Safer Chemicals
Objective:
A detailed project was conducted on the biogeochemistry of mercury (Hg) at Sunday Lake, a forested wetland/lake/watershed in the Adirondack region of New York. The overall objective of this study was to improve understanding of the inputs, transport, transformations, and fate of Hg in upland forest, wetland, and lake ecosystems. The specific objectives of the research project were to: (1) quantify patterns of transport and transformations of mercury species in an upland northern hardwood forest through adjacent wetlands to the aquatic environment; (2) evaluate the processes and mechanisms controlling methyl Hg (CH3Hg+) concentrations and transport in pore water and surface water in wetlands; (3) evaluate historical patterns of Hg dynamics in soft-water lakes; and (4) develop and apply a lake/watershed Hg cycling model to a lake/watershed ecosystem.
Summary/Accomplishments (Outputs/Outcomes):
Watershed measurements were taken, and a watershed mass balance study was conducted, including measurements of wet deposition, throughfall, litterfall, soil, soil water, vegetation, wetland porewater, hydrology, surface water chemistry, and aquatic biota. Sediment cores also were collected from eight lakes in the region to investigate historical patterns of Hg deposition. Finally, a Hg cycling model was developed and applied to Sunday Lake watershed.
Wet Hg deposition was 10.3 μg/m2-year, with 0.6 percent occurring as methyl Hg. Forest vegetation was important in mediating the inputs of Hg to the forest floor. Inputs of total Hg from litterfall and throughfall greatly exceeded wet Hg deposition, suggesting that dry deposition is 70 percent of the total Hg input to this forest ecosystem. The pathway of Hg inputs differed between coniferous and deciduous plots. Total Hg inputs at the coniferous plot largely occurred via throughfall, whereas litterfall dominated Hg inputs at the hardwood plot. Concentrations and fluxes of total Hg were elevated in forest floor leachate, with soil solution concentrations decreasing in the mineral soil. Likewise, soil concentrations of Hg were highest in the forest floor (13-188 ng/g) and decreased with increasing depth in the mineral soil. Concentrations of Hg in surface waters ranged from 1.9 to 4.6 ng/L, with methyl Hg concentrations from 0.2 to 2.53 ng/L. Atmospheric Hg deposition was retained in the watershed. Sunday Pond is a sink for inputs of total Hg. The watershed, particularly riparian wetlands, and the lake were net sources of methyl Hg to downstream surface waters. Concentrationsof Hg increased with each trophic level in the aquatic food chain. Mercury bioconcentration factors were lower in zooplankton and in fish than have been reported in other studies, probably due to binding of methyl Hg with high concentrations of organic solutes.
Concentrations of total Hg and 210Pb date were determined in sections of sediment cores collected from eight lakes in the Adirondacks. Although there were lake-to-lake variations, on average, sites showed a 5.8-fold increase in sediment Hg deposition from background values (before 1900) to peak values. Hg deposition peaked (from 1973 to 1995) and decreased in recent years. Current sediment Hg deposition is 3.5 times background values. For a given year, sediment Hg deposition increased with increasing watershed area to lake surface area. Conducting this analysis for preanthropogenic conditions, we estimated the deposition of Hg to the surface of a perched seepage lake (i.e., watershed area to lake surface area of one) was 3.4 + 1.0 μg/m2-year. For modern conditions, we determined the deposition of Hg to the surface of a perched seepage lake was 8.6 + 2.4 μg/m2-year; a value similar to current estimates of wet Hg deposition. Using sediment deposition data across the project lakes, it appears that the retention of Hg in Adirondack lakes and watersheds has been decreasing over the past 200 years. The mechanism responsible for this decline is unclear.
The Hg biogeochemistry data collected in this project were used to develop and calibrate the Mercury Cycling Model for headwater drainage lakes. Hypothetical calculations have been conducted to evaluate the response of Sunday Lake to decreases in atmospheric Hg deposition.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 28 publications | 1 publications in selected types | All 1 journal articles |
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Perry E, Norton SA, Kamman NC, Lorey PM, Driscoll CT. Deconstruction of historic mercury accumulation in lake sediments, northeastern United States. Ecotoxicology 2005;14(1-2):85-99. |
R827633 (Final) |
Exit |
Supplemental Keywords:
air, water, watersheds, groundwater, land, soil, acidic deposition, Mercury Deposition Network, precipitation, chemical transport, ecological effects, bioavailability, mercury, methyl mercury, acid rain, ecosystem, indicators, terrestrial, aquatic, wetlands, habitat, integrated assessment, public policy, decision making, fate and bioavailability of atmospheric mercury, environmental chemistry, biology, environmental engineering, ecosystem science, hydrology, geology, mathematics, limnology, modeling, monitoring, chemical analysis, watershed study, northeast, States, New York, NY, EPA Regions, EPA Region 2,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Geographic Area, Water, Waste, Air Deposition, Fate & Transport, Mercury, State, Ecosystem Protection, Chemistry, Environmental Chemistry, Ecosystem/Assessment/Indicators, Contaminated Sediments, Ecological Effects - Environmental Exposure & Risk, Bioavailability, Hydrology, heavy metals, wetland, water acidification, Clean Air Act, contaminated sediment, lake ecosystem, aquatic, atmospheric deposition, watershed influences, fate and transport, New York (NY), ecological exposure, forested watersheds, lake ecosystems, mercury cycling, upland ecosystems, lake sediment, surface water, dissolved organic carbon, mercury cycleRelevant Websites:
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.