Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1,469 lakes thr... more Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1,469 lakes throughout the Adirondack region shows that a significant fraction of the organic acids in ALSC waters were strong acids. This influenced both the pH and the Gran-titrated acid-neutralizing capacity (ANC) of the waters. The influence on pH was strongest at ANC values between 0 and 50 ueq/L where organic acids depressed pH by up to 1.5 units. Gran ANC values were generally less than C[sub B] - C[sub A] ANC values due to the effects of organic acids. These strong organics are capable of producing negative values of Gran ANC even when the C[sub B] - C[sub A] is positive. Thus, the common practice of considering negative values of Gran ANC evidence of acidification solely by mineral acids is not valid. The ALSC data have also provided ameans of performing parametric sensitivity analyses without having to rely on equilibrium models and the uncertainties of the equilibrium constants embedded in such codes. Instead, the sensitivity analyses were based solely on the data. This provides a powerful and direct means of determining the response of lake pH to a variety of environmental changes.
In 1987, EPRI's Land and Water Quality Studies Program initiated a multi-phase project entitl... more In 1987, EPRI's Land and Water Quality Studies Program initiated a multi-phase project entitled ''Environment Behavior of Organic Substances''. The objectives of this project are to develop data and methods for predicting the release, transport, transformation, and fate of organic compounds. Tetra Tech was contracted to compile and evaluate available data for 53 organic compounds. The chemicals include polycyclic aromatic hydrocarbons, monocyclic aromatics, heterocyclics, and halogenated aliphatics. The types of data compiled for each compound include physical and thermodynamic properties, equilibrium coefficients (for acid-base dissociation and adsorption-desorption), and reaction rate constants (for volatilization, hydrolysis, photolysis, and biotransformation). Data were evaluated for over 330 experiments described in about 250 references. The values selected were entered into an interactive data base management system. This report is the first volume of a two...
This report is the second volume of a two volume series. It includes a complete listing of the ph... more This report is the second volume of a two volume series. It includes a complete listing of the physical and chemical properties and equilibrium and rate constants for the 53 compounds. An index is included showing the types of data available for each chemical. Volume 1 discusses methods used to evaluate the data and estimate missing values. Review of available information indicates that the data for transformation rates are less available than for physical and chemical properties. In particular, additional rate data for biotransformation and photolysis are most needed. Where such data do exist in the literature, the values are typically for experiments performed under laboratory conditions. Because of this, methods and examples are included in volume 1 for adjusting such values to field conditions (e.g., different temperatures). 254 refs., 10 tabs.
A wide variety of processes influence the acid-base characteristics of precipitation as it flows ... more A wide variety of processes influence the acid-base characteristics of precipitation as it flows through a watershed and into streams and lakes. These include deposition, hydrologie and chemical processes occurring in terrestrial systems, and biological and chemical interactions that take place within streams and lakes.
The primary objective of this investigation was to test the hydrologic and chemical theory develo... more The primary objective of this investigation was to test the hydrologic and chemical theory developed during the Integrated Lake Watershed Acidification Study (ILWAS). A secondary objective was to assess the distribution of fish species among lakes of varying water quality. A total of 24 lake-watershed systems across the Adirondacks served as stuey sites over a period of two years. The
In late 1988, parallel studies of Lake Five‐O (pH 5.14) in the Florida panhandle and Lake Barco (... more In late 1988, parallel studies of Lake Five‐O (pH 5.14) in the Florida panhandle and Lake Barco (pH 4.50) in north central Florida were initiated to develop hydrologic and major ion budgets of these lakes as part of an overall effort to improve understanding of the hydrologic, depositional, and biogeochemical factors that control acid‐neutralizing capacity (ANC) in seepage lakes. Preliminary findings from these studies indicate that earlier perceptions of lake hydrology and mechanisms of ANC regulation in Florida seepage lakes may have to be revised. The traditional perspective of seepage lakes in the Florida panhandle views these systems as dominated by precipitation inputs and that ANC regulation is due largely to in‐lake processes. Our results for Lake Five‐O show modest to steep hydraulic gradients almost entirely around the lake. In addition, the horizontal hydraulic conductivity of the surficial aquifer is high (8–74 m day−1), indicating that large quantities of groundwater fl...
Mineral acids and bases influence p H largely through their effects on acid-neutralizing capacity... more Mineral acids and bases influence p H largely through their effects on acid-neutralizing capacity (ANC). This influence becomes particularly significant as ANC approaches zero. Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1469 lakes throughout the Adirondack region indicates that variations in ANC in these lakes correlate well with base cation concentrations (CB), but not with the sum of mineral acid union concentrations t CA)-This is because (CA) is relatively constant across the Adirondacks, whereas C• varies widely. Processes that supply base cations to solution are ion-specific. Sodium and silica concentrations are well correlated, indicating a common source, mineral weathering. Calcium and magnesium also covary but do not correlate well with silica. This indicates that ion exchange is a significant source of these cations in the absence of carbonate minerals. Iron and manganese concentrations are elevated in the lower waters of some lakes due to reducing conditions. This leads to an ephemeral increase in C• and ANC. When the lakes mix and oxic conditions are restored, these ions largely precipitate from solution. Sulfate is the dominant mineral acid union in ALSC lakes. Sulfate concentrations are lowest in seepage lakes, commonly about 40/aeq/L less than in drainage lakes. This is due in part to the longer hydraulic detention time in seepage lakes, which allows slow sulfate reduction reactions more time to decrease lake sulfate concentration. Nitrate typically influences ANC during events such as snowmelt. Chloride concentrations are generally low, except in lakes impacted by road salt. INTRODUCTION Much of the debate in the United States concerning the effects of acidic deposition on surface water chemistry and fish communities has focused on the Adirondack region of New York State (Figure 1). To better characterize the chemical and biological status of Adirondack lakes, the Adirondack Lakes Survey Corporation (ALSC) wax formed as a cooperative effort of the New York State Department of Environmental Conservation (NYSDEC)and the Empire State Electric Energy Research Corporation (ESEERCO). Between 1984 and 1987, the ALSC surveyed 1469 lakes within the Adirondack ecological zone. Detailed descriptions of the survey objectives, design, and techniques are provided in the ALSC summary report [Kretser et al., 1989]. A brief overview is given below. The ALSC survey provides an extremely comprehensive overview of the current status of water chemistry. and fish communities in Adirondack lakes. It builds upon previous, less detailed studies described by Schofield [1976], Brakke et al. [1988] and Driscoll et al. [1991]. The lakes sampled are distributed within the five major watersheds originating in the Adirondack ecological zone: Lake Champlain, Oswegatchie-Black, St. Lawrence-Raquette, Upper Hudson, and Mohawk-Hudson (Figures 1 and 2). The ecological zone is defined as the area generally lying within the 305-m (1000 feet) elevation contour surrounding the Adirondack uplands and mountain region. The ecological zone covers approximately 2.6 million ha (10,000 square miles); 2759 individual lakes and ponds greater than 0.2 ha in size (more than 99,000 ha of lake area) have been identified on U.S. Geological Survey (USGS) 15-minute and 7.5-minute maps within the zone boundary [Colquhoun et al., 1984]. The ALSC surveyed !469 or 53% of these waters.
Meander Lake in northeastern Minnesota was classified as extremely sensitive to acid deposition... more Meander Lake in northeastern Minnesota was classified as extremely sensitive to acid deposition, due to its low alkalinity. The ILWAS model was applied to determine its actual sensitivity. The model was calibrated with observed data and then used to evaluate the ...
ABSTRACT The terrestrial cycling of mercury has been studied at Sunday Lake watershed in the Adir... more ABSTRACT The terrestrial cycling of mercury has been studied at Sunday Lake watershed in the Adirondack region of New York State. This study has focused on two forest sites (a coniferous and a deciduous stand) and a wetland site, and involves measurements of total mercury and methyl mercury in through-fall, leaf litter, soil, soil water, and groundwater. Preliminary results indicate that total mercury in through-fall varied with vegetation type. Higher concentrations of total mercury were evident in through-fall at the coniferous site (3.0-38.2 ng/L, average 23.7 ng/L HgT) than at the deciduous site (1.0-3.8 ng/L, average 2.0 ng/L HgT). Soil concentrations varied with horizon but not significantly between sites. Soil mercury concentrations were highest in the forest floor (13.2-188.9 ng/g) and Bh horizon (3.7-67.5 ng/g), lower in the Bs horizon (2.7-47.5 ng/g), and lowest in the E horizon (3.9-25.2 ng/g). Concentrations of total mercury from the soil solutions were highest in forest floor leachate (9.8-41.8 ng/L) and decreased through the Bh horizon (0.9-13.9 ng/L) and Bs horizons (0.9-11.0 ng/L) at both sites. Methyl mercury concentrations in the soil solutions were low and/or not detectable throughout the soil profiles at both sites. The total mercury and methyl mercury concentrations in wetland groundwaters varied greatly ranging from 1.1 ng/L to 10.6 ng/L for total mercury and 0.5 ng/L to 6.5 ng/L for methyl mercury
ABSTRACT Wetlands play a prominent role in the cycling of mercury by harboring bacteria that tran... more ABSTRACT Wetlands play a prominent role in the cycling of mercury by harboring bacteria that transform mercury into methyl mercury, a neurotoxin, and by having high concentrations of dissolved organic carbon (DOC) that interact with mercury transport. We are measuring total mercury and methyl mercury in vegetation, soil, surface water, and ground water in the Sunday Lake watershed, in which wetlands cover 274 ha of the 1340-ha watershed area. Three wetland types occur: (1) riparian wetlands adjacent to low-order streams that drain the upland forested watershed; (2) peat-forming wetlands dominated by Carex sedges; and, (3) low shrub, Sphagnum (bog moss) dominated peatlands. Total mercury concentrations in wetland ground waters were greater in the riparian wetland (10.6 ng/L) and in sites with shallow peat than deep peat, suggesting water moves more readily around the peat than through it. The highest rates of microbial activity occurred in the top 10-cm of the sedge-derived peat, presumably being fueled by the freshest organic matter, although there was no relationship between microbial activity and DOC. Microbial sulfate reduction, which can methylate inorganic mercury, occurred in sites closest to low-order streams, presumably being fueled by sulfate brought into wetlands in surface water. Sites located away from the stream had microbial methane production, where demethylation might be occurring. Overall the wetlands are the primary source of methyl mercury within the watershed, and we are measuring water flow pathways and microbial processes to learn more about wetland controls of mercury cycling in watersheds.
ABSTRACT A detailed study is being conducted on the biogeochemistry of Hg at Sunday Pond, a fores... more ABSTRACT A detailed study is being conducted on the biogeochemistry of Hg at Sunday Pond, a forested wetland/lake/watershed in the Adirondack region of New York. Wet Hg deposition was 10.8 mg/m2-yr, with 0.6 percent occurring as methyl Hg. 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. Drainage water concentrations of Hg seem to be related to concentrations of dissolved organic carbon. A preliminary mass balance shows that about 79 percent of wet Hg deposition is retained in the watershed. Sunday Pond is a sink for inputs of total Hg. However, the watershed and lake are sources of methyl Hg to downstream surface waters. The Hg biogeochemistry data are being used to calibrate the Mercury in Adirondack Wetlands Lakes and Terrestrial Systems (MAWLTS) model for the site.
The purpose of this study is to examine the inputs and fate of Hg within a forest-wetland-lake wa... more The purpose of this study is to examine the inputs and fate of Hg within a forest-wetland-lake watershed ecosystem. Results of analyzing Mercury (Hg) is a toxic trace metal, that has been linked to human individual fluxes/compartments will be integrated to examine the illness and degradation of ecosystems. Atmospheric emissions have processes affecting Hg fate within the watershed. For the examination caused widespread contamination of Hg in terrestrial and aquatic of the various processes, instrumentation was installed at various sites environments, including dangerously high concentrations in within the watershed to: Adirondack lake biota. However, the linkage between atmospheric deposition and contamination of aquatic biota is not well established. 1. Measure atmospheric interactions, including direct deposition, Additional research is necessary to determine the ultimate fate of Hg throughfall, evasion, and canopy Hg profiles. within remote ecosystems. A quantitative understanding of atmospheric Hg deposition and the factors regulating the fate, 2. Evaluate the transport and speciation of deposited Hg within an upland transformation, and bioavailability of such Hg within terrestrial terrestrial system, including the application of stable isotope to track environments and downstream aquatic ecosystems are critical Hg fate. research needs. 3. Conduct Hg budgets on Arbutus Lake and an associated inlet stream The current research examines Hg deposition and cycling within the wetland system. The budget for Arbutus (high rT, low DOC) is being Arbutus Lake watershed (Newcomb, NY) to clarify the atmospheric, compared with Sunday Lake (low rT, high DOC). geochemical, and biological mechanisms regulating Hg concentrations in soft-water lakes of the northeastern U.S. The effects of deposition pathway, soil retention, and landscape Figure 1. Processes affecting the fate of Hg within a watershed. Input is characteristics are being examined. Data obtained within the Arbutus
This reportwas preparedas an accountof worksponsoredby an agencyof the United States Government.N... more This reportwas preparedas an accountof worksponsoredby an agencyof the United States Government.Neitherthe UnitedStates Governn'lent norany agencythereof,nor any of their employees,makesany warranty, expressor implied,or assumesany legal liabilityor responsibility for the accuracy, completeness, or usefulnessof any information, apparatus, prodt_ct, or processdisclosed,or represents that its use wouldnot infringeprivatelyowned rights.Reference hereinto anyspecificcommercial product, process,or serviceby tradename,trademark, manufacturer, or otherwisedoes not necessarilyconstituteor implyits endorsement, recommendation,or favoringby the United States Government or any agencythereof.The views and opinionsof authorsexpressedherein do not necessarilystate or reflect those of the UnitedStates Government or any agencythereof.
Two demonstration treatment wetland systems were studied for over four years. Both consisted of s... more Two demonstration treatment wetland systems were studied for over four years. Both consisted of sedimentation basins, followed by wetland cells. The Imperial, CA system had four wetland cells totaling 4.7ha, 25% vegetated with bulrushes (Schoenoplectus californicus), and the Brawley, CA system had two wetland cells totaling 1.8ha, also 25% vegetated with bulrushes. Imperial received irrigation runoff water at 30cm/day, and
A number of recent studies have documented elevated concentrations of mercury (Hg) in fish caught... more A number of recent studies have documented elevated concentrations of mercury (Hg) in fish caught in remote lakes and a pattern of increased concentrations of Hg in fish tissue with decreasing water column pH. Because of the potential linkage between fish Hg and surface water acidification, factors regulating water column concentrations and bioavailability of Hg were investigated in Adirondack lakes
Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1,469 lakes thr... more Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1,469 lakes throughout the Adirondack region shows that a significant fraction of the organic acids in ALSC waters were strong acids. This influenced both the pH and the Gran-titrated acid-neutralizing capacity (ANC) of the waters. The influence on pH was strongest at ANC values between 0 and 50 ueq/L where organic acids depressed pH by up to 1.5 units. Gran ANC values were generally less than C[sub B] - C[sub A] ANC values due to the effects of organic acids. These strong organics are capable of producing negative values of Gran ANC even when the C[sub B] - C[sub A] is positive. Thus, the common practice of considering negative values of Gran ANC evidence of acidification solely by mineral acids is not valid. The ALSC data have also provided ameans of performing parametric sensitivity analyses without having to rely on equilibrium models and the uncertainties of the equilibrium constants embedded in such codes. Instead, the sensitivity analyses were based solely on the data. This provides a powerful and direct means of determining the response of lake pH to a variety of environmental changes.
In 1987, EPRI's Land and Water Quality Studies Program initiated a multi-phase project entitl... more In 1987, EPRI's Land and Water Quality Studies Program initiated a multi-phase project entitled ''Environment Behavior of Organic Substances''. The objectives of this project are to develop data and methods for predicting the release, transport, transformation, and fate of organic compounds. Tetra Tech was contracted to compile and evaluate available data for 53 organic compounds. The chemicals include polycyclic aromatic hydrocarbons, monocyclic aromatics, heterocyclics, and halogenated aliphatics. The types of data compiled for each compound include physical and thermodynamic properties, equilibrium coefficients (for acid-base dissociation and adsorption-desorption), and reaction rate constants (for volatilization, hydrolysis, photolysis, and biotransformation). Data were evaluated for over 330 experiments described in about 250 references. The values selected were entered into an interactive data base management system. This report is the first volume of a two...
This report is the second volume of a two volume series. It includes a complete listing of the ph... more This report is the second volume of a two volume series. It includes a complete listing of the physical and chemical properties and equilibrium and rate constants for the 53 compounds. An index is included showing the types of data available for each chemical. Volume 1 discusses methods used to evaluate the data and estimate missing values. Review of available information indicates that the data for transformation rates are less available than for physical and chemical properties. In particular, additional rate data for biotransformation and photolysis are most needed. Where such data do exist in the literature, the values are typically for experiments performed under laboratory conditions. Because of this, methods and examples are included in volume 1 for adjusting such values to field conditions (e.g., different temperatures). 254 refs., 10 tabs.
A wide variety of processes influence the acid-base characteristics of precipitation as it flows ... more A wide variety of processes influence the acid-base characteristics of precipitation as it flows through a watershed and into streams and lakes. These include deposition, hydrologie and chemical processes occurring in terrestrial systems, and biological and chemical interactions that take place within streams and lakes.
The primary objective of this investigation was to test the hydrologic and chemical theory develo... more The primary objective of this investigation was to test the hydrologic and chemical theory developed during the Integrated Lake Watershed Acidification Study (ILWAS). A secondary objective was to assess the distribution of fish species among lakes of varying water quality. A total of 24 lake-watershed systems across the Adirondacks served as stuey sites over a period of two years. The
In late 1988, parallel studies of Lake Five‐O (pH 5.14) in the Florida panhandle and Lake Barco (... more In late 1988, parallel studies of Lake Five‐O (pH 5.14) in the Florida panhandle and Lake Barco (pH 4.50) in north central Florida were initiated to develop hydrologic and major ion budgets of these lakes as part of an overall effort to improve understanding of the hydrologic, depositional, and biogeochemical factors that control acid‐neutralizing capacity (ANC) in seepage lakes. Preliminary findings from these studies indicate that earlier perceptions of lake hydrology and mechanisms of ANC regulation in Florida seepage lakes may have to be revised. The traditional perspective of seepage lakes in the Florida panhandle views these systems as dominated by precipitation inputs and that ANC regulation is due largely to in‐lake processes. Our results for Lake Five‐O show modest to steep hydraulic gradients almost entirely around the lake. In addition, the horizontal hydraulic conductivity of the surficial aquifer is high (8–74 m day−1), indicating that large quantities of groundwater fl...
Mineral acids and bases influence p H largely through their effects on acid-neutralizing capacity... more Mineral acids and bases influence p H largely through their effects on acid-neutralizing capacity (ANC). This influence becomes particularly significant as ANC approaches zero. Analysis of data collected by the Adirondack Lakes Survey Corporation (ALSC) from 1469 lakes throughout the Adirondack region indicates that variations in ANC in these lakes correlate well with base cation concentrations (CB), but not with the sum of mineral acid union concentrations t CA)-This is because (CA) is relatively constant across the Adirondacks, whereas C• varies widely. Processes that supply base cations to solution are ion-specific. Sodium and silica concentrations are well correlated, indicating a common source, mineral weathering. Calcium and magnesium also covary but do not correlate well with silica. This indicates that ion exchange is a significant source of these cations in the absence of carbonate minerals. Iron and manganese concentrations are elevated in the lower waters of some lakes due to reducing conditions. This leads to an ephemeral increase in C• and ANC. When the lakes mix and oxic conditions are restored, these ions largely precipitate from solution. Sulfate is the dominant mineral acid union in ALSC lakes. Sulfate concentrations are lowest in seepage lakes, commonly about 40/aeq/L less than in drainage lakes. This is due in part to the longer hydraulic detention time in seepage lakes, which allows slow sulfate reduction reactions more time to decrease lake sulfate concentration. Nitrate typically influences ANC during events such as snowmelt. Chloride concentrations are generally low, except in lakes impacted by road salt. INTRODUCTION Much of the debate in the United States concerning the effects of acidic deposition on surface water chemistry and fish communities has focused on the Adirondack region of New York State (Figure 1). To better characterize the chemical and biological status of Adirondack lakes, the Adirondack Lakes Survey Corporation (ALSC) wax formed as a cooperative effort of the New York State Department of Environmental Conservation (NYSDEC)and the Empire State Electric Energy Research Corporation (ESEERCO). Between 1984 and 1987, the ALSC surveyed 1469 lakes within the Adirondack ecological zone. Detailed descriptions of the survey objectives, design, and techniques are provided in the ALSC summary report [Kretser et al., 1989]. A brief overview is given below. The ALSC survey provides an extremely comprehensive overview of the current status of water chemistry. and fish communities in Adirondack lakes. It builds upon previous, less detailed studies described by Schofield [1976], Brakke et al. [1988] and Driscoll et al. [1991]. The lakes sampled are distributed within the five major watersheds originating in the Adirondack ecological zone: Lake Champlain, Oswegatchie-Black, St. Lawrence-Raquette, Upper Hudson, and Mohawk-Hudson (Figures 1 and 2). The ecological zone is defined as the area generally lying within the 305-m (1000 feet) elevation contour surrounding the Adirondack uplands and mountain region. The ecological zone covers approximately 2.6 million ha (10,000 square miles); 2759 individual lakes and ponds greater than 0.2 ha in size (more than 99,000 ha of lake area) have been identified on U.S. Geological Survey (USGS) 15-minute and 7.5-minute maps within the zone boundary [Colquhoun et al., 1984]. The ALSC surveyed !469 or 53% of these waters.
Meander Lake in northeastern Minnesota was classified as extremely sensitive to acid deposition... more Meander Lake in northeastern Minnesota was classified as extremely sensitive to acid deposition, due to its low alkalinity. The ILWAS model was applied to determine its actual sensitivity. The model was calibrated with observed data and then used to evaluate the ...
ABSTRACT The terrestrial cycling of mercury has been studied at Sunday Lake watershed in the Adir... more ABSTRACT The terrestrial cycling of mercury has been studied at Sunday Lake watershed in the Adirondack region of New York State. This study has focused on two forest sites (a coniferous and a deciduous stand) and a wetland site, and involves measurements of total mercury and methyl mercury in through-fall, leaf litter, soil, soil water, and groundwater. Preliminary results indicate that total mercury in through-fall varied with vegetation type. Higher concentrations of total mercury were evident in through-fall at the coniferous site (3.0-38.2 ng/L, average 23.7 ng/L HgT) than at the deciduous site (1.0-3.8 ng/L, average 2.0 ng/L HgT). Soil concentrations varied with horizon but not significantly between sites. Soil mercury concentrations were highest in the forest floor (13.2-188.9 ng/g) and Bh horizon (3.7-67.5 ng/g), lower in the Bs horizon (2.7-47.5 ng/g), and lowest in the E horizon (3.9-25.2 ng/g). Concentrations of total mercury from the soil solutions were highest in forest floor leachate (9.8-41.8 ng/L) and decreased through the Bh horizon (0.9-13.9 ng/L) and Bs horizons (0.9-11.0 ng/L) at both sites. Methyl mercury concentrations in the soil solutions were low and/or not detectable throughout the soil profiles at both sites. The total mercury and methyl mercury concentrations in wetland groundwaters varied greatly ranging from 1.1 ng/L to 10.6 ng/L for total mercury and 0.5 ng/L to 6.5 ng/L for methyl mercury
ABSTRACT Wetlands play a prominent role in the cycling of mercury by harboring bacteria that tran... more ABSTRACT Wetlands play a prominent role in the cycling of mercury by harboring bacteria that transform mercury into methyl mercury, a neurotoxin, and by having high concentrations of dissolved organic carbon (DOC) that interact with mercury transport. We are measuring total mercury and methyl mercury in vegetation, soil, surface water, and ground water in the Sunday Lake watershed, in which wetlands cover 274 ha of the 1340-ha watershed area. Three wetland types occur: (1) riparian wetlands adjacent to low-order streams that drain the upland forested watershed; (2) peat-forming wetlands dominated by Carex sedges; and, (3) low shrub, Sphagnum (bog moss) dominated peatlands. Total mercury concentrations in wetland ground waters were greater in the riparian wetland (10.6 ng/L) and in sites with shallow peat than deep peat, suggesting water moves more readily around the peat than through it. The highest rates of microbial activity occurred in the top 10-cm of the sedge-derived peat, presumably being fueled by the freshest organic matter, although there was no relationship between microbial activity and DOC. Microbial sulfate reduction, which can methylate inorganic mercury, occurred in sites closest to low-order streams, presumably being fueled by sulfate brought into wetlands in surface water. Sites located away from the stream had microbial methane production, where demethylation might be occurring. Overall the wetlands are the primary source of methyl mercury within the watershed, and we are measuring water flow pathways and microbial processes to learn more about wetland controls of mercury cycling in watersheds.
ABSTRACT A detailed study is being conducted on the biogeochemistry of Hg at Sunday Pond, a fores... more ABSTRACT A detailed study is being conducted on the biogeochemistry of Hg at Sunday Pond, a forested wetland/lake/watershed in the Adirondack region of New York. Wet Hg deposition was 10.8 mg/m2-yr, with 0.6 percent occurring as methyl Hg. 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. Drainage water concentrations of Hg seem to be related to concentrations of dissolved organic carbon. A preliminary mass balance shows that about 79 percent of wet Hg deposition is retained in the watershed. Sunday Pond is a sink for inputs of total Hg. However, the watershed and lake are sources of methyl Hg to downstream surface waters. The Hg biogeochemistry data are being used to calibrate the Mercury in Adirondack Wetlands Lakes and Terrestrial Systems (MAWLTS) model for the site.
The purpose of this study is to examine the inputs and fate of Hg within a forest-wetland-lake wa... more The purpose of this study is to examine the inputs and fate of Hg within a forest-wetland-lake watershed ecosystem. Results of analyzing Mercury (Hg) is a toxic trace metal, that has been linked to human individual fluxes/compartments will be integrated to examine the illness and degradation of ecosystems. Atmospheric emissions have processes affecting Hg fate within the watershed. For the examination caused widespread contamination of Hg in terrestrial and aquatic of the various processes, instrumentation was installed at various sites environments, including dangerously high concentrations in within the watershed to: Adirondack lake biota. However, the linkage between atmospheric deposition and contamination of aquatic biota is not well established. 1. Measure atmospheric interactions, including direct deposition, Additional research is necessary to determine the ultimate fate of Hg throughfall, evasion, and canopy Hg profiles. within remote ecosystems. A quantitative understanding of atmospheric Hg deposition and the factors regulating the fate, 2. Evaluate the transport and speciation of deposited Hg within an upland transformation, and bioavailability of such Hg within terrestrial terrestrial system, including the application of stable isotope to track environments and downstream aquatic ecosystems are critical Hg fate. research needs. 3. Conduct Hg budgets on Arbutus Lake and an associated inlet stream The current research examines Hg deposition and cycling within the wetland system. The budget for Arbutus (high rT, low DOC) is being Arbutus Lake watershed (Newcomb, NY) to clarify the atmospheric, compared with Sunday Lake (low rT, high DOC). geochemical, and biological mechanisms regulating Hg concentrations in soft-water lakes of the northeastern U.S. The effects of deposition pathway, soil retention, and landscape Figure 1. Processes affecting the fate of Hg within a watershed. Input is characteristics are being examined. Data obtained within the Arbutus
This reportwas preparedas an accountof worksponsoredby an agencyof the United States Government.N... more This reportwas preparedas an accountof worksponsoredby an agencyof the United States Government.Neitherthe UnitedStates Governn'lent norany agencythereof,nor any of their employees,makesany warranty, expressor implied,or assumesany legal liabilityor responsibility for the accuracy, completeness, or usefulnessof any information, apparatus, prodt_ct, or processdisclosed,or represents that its use wouldnot infringeprivatelyowned rights.Reference hereinto anyspecificcommercial product, process,or serviceby tradename,trademark, manufacturer, or otherwisedoes not necessarilyconstituteor implyits endorsement, recommendation,or favoringby the United States Government or any agencythereof.The views and opinionsof authorsexpressedherein do not necessarilystate or reflect those of the UnitedStates Government or any agencythereof.
Two demonstration treatment wetland systems were studied for over four years. Both consisted of s... more Two demonstration treatment wetland systems were studied for over four years. Both consisted of sedimentation basins, followed by wetland cells. The Imperial, CA system had four wetland cells totaling 4.7ha, 25% vegetated with bulrushes (Schoenoplectus californicus), and the Brawley, CA system had two wetland cells totaling 1.8ha, also 25% vegetated with bulrushes. Imperial received irrigation runoff water at 30cm/day, and
A number of recent studies have documented elevated concentrations of mercury (Hg) in fish caught... more A number of recent studies have documented elevated concentrations of mercury (Hg) in fish caught in remote lakes and a pattern of increased concentrations of Hg in fish tissue with decreasing water column pH. Because of the potential linkage between fish Hg and surface water acidification, factors regulating water column concentrations and bioavailability of Hg were investigated in Adirondack lakes
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