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Trends in anthropogenically driven episodic acidification associated with extended winter snow melt/rain episodes between 1983 and 1998 were investigated for two streams in Nova Scotia, Canada. The anthropogenic contribution to Acid Neutralization Capacity (ANC) was analysed using the Boreal Dilution Model (Bishop et al., 2000) modified by applying a(More)
Reductions in North American sulfur dioxide (SO2) emissions promoted expectations that aquatic ecosystems in southeastern Canada would soon recover from acidification. Only lakes located near smelters that have dramatically reduced emissions approach this expectation. Lakes in the Atlantic provinces, Quebec and Ontario affected only by long-range sources(More)
Atlantic Canada, located in the extreme northeastern portion of North America, receives acid precipitation from all major acid emission sources on the eastern part of the continent. The region was glaciated and has thin soils over a generally poorly acid buffering bedrock. Because of regional topography, large groupings of lakes occur in a number of(More)
We report on an inventory and analysis of sediment mercury (Hg) concentrations from 579 sites across northeastern North America. Sediment Hg concentrations ranged from the limit of detection ca. 0.01-3.7 microg g(-1) (dry weight, d.w.), and the average concentration was 0.19 microg g(-1) (d.w.) Sediment methylmercury concentrations ranged from 0.15 to 21 ng(More)
A large number of datasets representing mercury (Hg) levels in northeastern North America were assembled in a standardized format between 2000 and 2003. Based on support from the Northeastern States Research Cooperative, scientists annually gathered and developed an operational template to collaboratively analyze and interpret these data for a series of(More)
We assembled 831 data points for total mercury (Hg(t)) and 277 overlapping points for methyl mercury (CH3Hg+) in surface waters from Massachussetts, USA to the Island of Newfoundland, Canada from State, Provincial, and Federal government databases. These geographically indexed values were used to determine: (a) if large-scale spatial distribution patterns(More)
Temperate forests can contain large numbers of wetlands located in areas of low relief and poor drainage. These wetlands can make a large contribution to the dissolved organic carbon (DOC) load of streams and rivers draining the forests, as well as the exchange of methane (CH4) and carbon dioxide (CO2) with the atmosphere. We studied the carbon budget of a(More)
The physical factors controlling total mercury (HgT) and methylmercury (MeHg) concentrations in lakes and streams of northeastern USA were assessed in a regional data set containing 693 HgT and 385 corresponding MeHg concentrations in surface waters. Multiple regression models using watershed characteristics and climatic variables explained 38% or less of(More)
The New England Governors and Eastern Canadian Premiers (NEG/ECP) adopted the Acid Rain Action Plan in June 1998, and issued a series of action items to support its work toward a reduction of sulfur dioxide (SO(2)) and nitrogen oxide (NO(x)) emissions in northeastern North America. One of these action items was the preparation of an updated critical load(More)