Grantee Research Project Results
2000 Progress 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
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 Period Covered by this Report: November 1, 1999 through October 31, 2000
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:
The objectives of this research project are 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 mercury concentrations and transport in pore waters and surface waters in wetlands; (3) evaluate historical patterns of mercury dynamics in soft-water lakes; and (4) develop and apply a lake/watershed mercury cycling model to a lake/watershed ecosystem.Progress Summary:
A detailed study is being conducted on the biogeochemistry of mercury (Hg) at Sunday Pond (41? 51' N, 75? 06' W) Watershed in the Adirondack region of New York. Sunday Pond Watershed (1340 ha) is largely forested (70 percent deciduous, 30 percent coniferous), with an abundance of wetlands. Sunday Pond is 7.7 ha, with a mean depth of 2.5 ha. This study involves the measurement of total Hg and methyl Hg in wet deposition, throughfall, litter, soil, soil waters, ground waters, surface waters, and sediments. Gauge stations have been established on the outlet stream of Sunday Pond and along the major inlet just upstream of the lake. A third station is operated in the area of the wetland on the east shore of the lake. This station records lake stage, air temperature, water temperature, and rainfall. Groundwater stage is monitored at a piezometer adjacent to the inlet monitoring station and at an additional station established next to a well in the wetland area. We have established a wet Hg deposition station at Huntington Forest through the National Atmospheric Deposition Program (NADP) Mercury Deposition Network (MDN). Replicate zero-tension Teflon lysimeters were installed beneath Oa, Bh, and within Bs soil horizons in plots with stands of coniferous and deciduous vegetation to sample soil waters. Prior to the installation of lysimeters, soil samples were collected by horizon for Hg analysis. Throughfall and litterfall collectors were established at both the deciduous and coniferous plots for sampling. Teflon peizometers were installed within the upland forest, the wetland on the east shore of the lake and in riparian wetlands adjacent to the major inlet of the lake to sample shallow groundwater. Surface samples are collected at seven sites established for inflowing tributaries of the lake, the lake surface and lower waters, and the lake outlet. A sediment core was collected, sectioned, dated, and measured for Hg concentrations.We estimated wet deposition of total Hg to the site to be 10.8 µg/m2-yr, with 0.6 percent of this occurring as methyl Hg. Concentrations and fluxes of total Hg were greatly elevated in forest floor leachate, with soil solution concentrations decreasing in the mineral soil. Concentrations of methyl Hg were low in upland soil solutions, near the analytical detection limit. Soil concentrations of total Hg were elevated in the forest floor (13-188 ng/g). Soil Hg concentrations were low in the E horizon (3.7-25.2 ng/g), higher in the zone of organic deposition or Bh horizon (1.3-3.4 ng/g), and low in the lower mineral soil or Bs horizon (1.7-3.1 ng/g). We observed elevated concentrations of methyl Hg in ground waters draining wetlands in the watershed. Lake inlet concentrations of total Hg ranged from 1.9 to 3.3 ng/L, with a mean of 3.0 ng/L. Methyl Hg concentrations were somewhat lower ranging from less than 10 percent to greater than 50 percent of total Hg. Lake concentrations of total Hg ranged from 2.0 to 4.6 ng/L, with methyl Hg ranging from 0.2 to 2.53 ng/L. Drainage water concentrations of total Hg appeared to be related to concentrations of dissolved organic carbon. A preliminary mass balance showed that 77 percent of wet Hg deposition is retained in the watershed. Sunday Pond also was a sink for inputs of total Hg. However, the watershed and lake were sources of methyl Hg to downstream surface waters. It appears that wetlands are important for the supply of methyl Hg to surface waters. The current lake/watershed mass balance was compared to historical patterns of Hg deposition in lake sediments. The Hg biogeochemistry data collected are being used to calibrate the Mercury in Adirondack Wetlands Lakes and Terrestrial Systems (MAWLTS) model to the Sunday Pond lake/watershed system.
Future Activities:
During the next year of the project, we plan to continue our ongoing measurements of Hg and other ancillary chemical solutes at Sunday Pond Watershed. We hope to expand our efforts to conduct detailed measurements and studies of Hg cycling in upland forests, through additional measurements in litter and throughfall. Through surveys and process-level studies we intend to investigate in more detail Hg transformations in wetlands. We plan to use MAWLTS as a research tool to help test hypotheses on controls on Hg transport and bioavailability in northern forest/wetland/lake ecosystems.Journal Articles:
No journal articles submitted with this report: View all 28 publications for this projectSupplemental Keywords:
soil, water, mercury, watershed, wetlands, lakes, Adirondacks., RFA, Scientific Discipline, Water, Waste, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Bioavailability, Hydrology, Contaminated Sediments, Ecosystem/Assessment/Indicators, Ecosystem Protection, Environmental Chemistry, Chemistry, State, Fate & Transport, Ecological Effects - Environmental Exposure & Risk, Air Deposition, Mercury, fate and transport, ecological exposure, aquatic, wetland ecosystem, forested watersheds, contaminated sediment, upland ecosystems, surface water, mercury cycling, mercury cycle, watershed influences, dissolved organic carbon, water acidification, Clean Air Act, lake sediment, lake ecosystem, wetland, atmospheric deposition, heavy metals, lake ecosystemsRelevant Websites:
http://www.science.smith.edu/departments/Geology/mercury/ Exit Synthesis Report of Research from EPA’s Science to Achieve Results (STAR) Grant Program: Mercury Transport and Fate Through a Watershed (PDF) (42 pp, 760 K)
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.