Comparison of excess sulfate yields and median pH values of rivers in Nova Scotia and Newfoundland, 1971–1973 and 1982–1984

Using the best available data, a comparison of the excess sulfate yields and median pH values of rivers in Nova Scotia and Newfoundland for the two periods 1971–1973 and 1982–1984 showed that the excess sulfate yields were significantly lower in the latter period, and the median pH values of the non-organically-dominated rivers were higher. The area] pattern of excess sulfate yields of rivers on the island of Newfoundland is in accord with the known pattern of precipitation across the island. Comparison of data for the Mersey River in Kejimkujik National Park, Nova Scotia, with measured wet deposition of excess sulfate showed that the river yields of excess sulfate are higher than the wet deposition by amounts that are likely due to dry deposition.     

Seasonal mass balance of major ions in three small watersheds in a maritime environment

Three watersheds (16.4, 544, and 83 ha) at distances of 0.5, 20, and 40 km from the Atlantic coast have been monitored for major ion chemistry of precipitation input and streamflow from May 1977 to November 1978. More than 200 precipitation and stramflow samples were analyzed for Na, K, Ca, Mg, chloride and sulphate, as well as pH, conductivity, alkalinity, and compared to similar studies at Hubbard Brook, New Hampshire, U.S.A., and Kejimkujik National Park, Nova Scotia. Major ion chemistry reflects proximity to Atlantic and Bay of Fundy coastal sources of marine aerosols. Evidence is presented implying biological reduction of H ⁺ and S04 to H₂S during summer months for two consecutive growing seasons. Weighted mean annual pH values of precipitation for the three watersheds in Nova Scotia range from 4.11 to 4.63. More than 50% of the H ⁺ in precipitation is retained in the watersheds (with the exception of the ombrotrophic Fink Cove ecosystem), principally at the expense of basic cations being leached from the watersheds. Acidic deposition of Nova Scotian precipitation is predominantly as sulphuric acid, in contrast to ammonium sulphate, characteristic of continental precipitation.     

Kejimkujik Park — One in a family of integrated watershed studies

The Canadian federal research program related to the Long-Range Transport of Airborne Pollutants included integrated studies to be carried out in selected watersheds. These watersheds were selected through consideration of the then existing studies as well as the need to provide information on the range of ecosystems susceptible to acidification in Canada. The biogeochemical characteristics of the site selected in the highly sensitive region of Nova Scotia, the Kejimkujik National Park, are presented in comparison with other integrated study sites in North America and in Europe. It is shown that the Kejimkujik site represents a system that is dominated by very dilute but highly organic waters not included in other studies.     

Chemical characterization of several wetlands in Kejimkujik National Park,Nova Scotia

Results are presented from an investigation of wetland chemistry in Kejimkujik National Park, Nova Scotia. Significant differences in the major ionic constituents occurred between wetlands classified as bogs and those classified as fens, indicating the more minerotrophic status of the latter. The fens, however, were categorized as extremely poor, being very low in pH and base cations, indicating almost no buffering capacity. This type of wetland is regarded as transitional to bog and is viewed as highly sensitive to acid deposition by Gorham et al. (1987). Further alkalinity losses may result in abrupt changes in floral assemblages with rapid invasion of carpet forming Sphagnum species.     

Sources of sulphate and acidity in wetlands and lakes in Nova Scotia

There is a declining gradient of wet SO₄ deposition from south to north in Nova Scotia with the highest values being in the south, along with a localized increase around the Halifax metropolitan area, due to local SO₄ emission. Edaphic conditions such as drainage from soils containing gypsum or drainage on disturbed rocks containing pyrite, provide additional SO₄ to surface waters.Acidity is usually absent in the former (pH > 7.0) and very high in the latter (as low as pH 3.6). By contrast peaty, organic drainages release water low in SO₄ during the growing season but they release high amounts of organic anions (A?), consequently, these waters maintain decreased pH values, usually < 4.5. A study of over 80 wetlands and lakes during the ice free period in Nova Scotia showed that sea salt corrected SO₄ concentrations range from 45 ueq L^?1 in the south end of the province, ～30 ueq L^?1 in the Kejimkujik area and < 17 ueq L^?1 in the northern areas with values > 85 ueq L^?1 in the Halifax area, reflecting the atmospheric deposition pattern of SO₄ The SO₄ concentrations may be > 2000 ueq L^?1 in drainages containing gypsum, > 700 ueq L^?1 in drainages over pyrite bearing socks but < 20 ueq/L^?1 in streams draining bogs. The SO₄ concentrations change considerably during the non-growing season when the ground is saturated with water or frozen, and the runoff is high (snow and rain often alternate in winter). Under such conditions SO₄ concentration drops in the two former cases and increases in bog drainages, accompanied with a considerable drop in (A?) concentrations. Care should be taken when interpreting SO₄ concentrations in surface waters in Nova Scotia with respect to atmospheric SO₄ deposition.     

Changes in Freshwater Acidification Trends in Canada's Atlantic Provinces: 1983–1997

Sixty-three lakes were sampled semi-annually for acid precipitation – related variables in Canada's Atlantic Provinces,Nova Scotia and Newfoundland from 1983 to 1997. A further 31 sites were sampled beginning in 1989 in Nova Scotia. We analyzedthe water chemistry data for trends in pH, acid neutralization capacity, sulfate and base cations using the whole data set for the original 63 sites and the most recent eight years' data for all sites. We also analyzed acid deposition at two CAPMoN precipitation chemistry sites located at the two extremes of thesampling region for trends. We found that hydrogen deposition decreased by 20% in Newfoundland and 30% in Nova Scotia, and sulfate decreased by 36 and 34%, respectively. Sulfate and basecations in lake waters showed decreases as expected, though lakeacidity and acid neutralization capacity did not show improvements. The conflicting trends in chemical variables suggest that though anthropogenically-induced weathering is diminishing in this region, conditions have not returned to `natural' background conditions.     

Aluminum species in porewaters of Kejimkujik and Mountain Lakes,Nova Scotia

Sediment porewaters were recovered by the membrane dialysis technique from Kejimkujik Lake and Mountain Lake in Nova Scotia and analyzed for pH, dissolved organic carbon (DOC), total (acid soluble) aluminum, total reactive monomeric aluminum (TRM-Al), organic monomeric aluminum and inorganic monomeric aluminum. The results show that in the colored lake water (Kejimkujik), close to 100% of the TRM-Al fraction is bound to organic matter and that 10 to 60% of the total-Al is in the monomeric form. In the clearwater lake (Mountain), 50 to 65% of TRM-Al fraction is associated with organic matter and less than 4 to 5% of the Total-Al is in the monomeric form. The concentrations of reactive monomeric species in organic-rich porewaters decrease with time of storage due to the precipitation of organo-Al compounds. Model calculations using the porewater profiles for Al suggest that the sediment can be an important source of dissolved Al to the overlying water.     

Ambient acid aerosols in rural Nova Scotia

During the summer months, Nova Scotia is downwind of many of the large industrial areas of the eastern United States and central Canada. The studies described here were carried out in the summers of 1983 and 1984 in Antigonish, a small rural town in northeastern Nova Scotia with no local sources. Twenty-four hour samples were collected on Teflon filters using a dichotomous sampler, and were analyzed for sulphate, nitrate and chloride by ion chromatography and for strong acid using Gran titrations. Sulphate episodes (up to 27 μg m^?3) were frequent. They usually occurred in warm, hazy weather and were often accompanied by strong acid (up to 9 μg m^?3 as H₂SO₄).     

Wet deposition of mercury and ambient mercury concentrations at a site in the Lake Champlain basin

The “Great Waters” program, established in the 1990 Clean Air Act Amendments, mandated that atmospheric deposition of hazardous air pollutants to Lake Champlain (including Hg) be assessed. An assessment of the magnitude and seasonal variation of atmospheric Hg deposition in the Lake Champlain basin was initiated in December 1992 with one year of event precipitation collection, as well as collection of vapor and particle phase Hg in ambient air. Samples were collected at the Vermont Monitoring Cooperative air monitoring site at the Proctor Maple Research Center in Underhill Center, VT. The average volume-weighted concentration for Hg in precipitation was 8.3 ng/L for the sampling year and the average amount of Hg deposited with each precipitation event was 0.069 μg/m². The total amount of Hg deposited through precipitation during 1993 was 9.26 μg/m²/yr. A seasonal pattern for Hg in precipitation was evident, with increased concentrations and deposition during spring and summer months. Meteorological analysis indicated the highest levels of Hg in precipitation were associated with regional transport from the south regardless of season, and with transport from the west, southwest and northwest during spring and summer months. Concentrations of ambient vapor phase Hg were typical of rural locations and consistent across seasons. Ambient particulate Hg concentrations averaged 11 pg/m³ with highest concentrations during the winter months.     

Organic versus anthropogenic acidity in tributaries of the kejimkujik watersheds in Western Nova Scotia

Dilute waters (Ca = 0.3 to 0.8 mg L^?1) respond by depressed pH levels throughout the year to existing atmospheric wet deposition of sulphate (20 kg ha^?1yr^?1).This occurs in southwest Nova Scotia particularly during the cold, wet season when runoff is high. Colored waters of similar Ca levels receiving runoff from peaty catchments exhibit pH values one unit lower (4.7 to 4.1) than those of catchments of similar Ca levels but free from peat deposits (pH > 5.3). In colored streams sulphate and organic anions show opposing cyclic patterns while the negative gran alkalinity is the near mirror image of sulphate. Sulphate anion peaks during the high spring discharge when the organic anion concentration is lowest. Sulphate suddenly drops during the summer months during periods of high evapotranspiration, low water table and runoff, when the concentration of organic anions is highest. Both Al and Fe follow cyclic patterns similar to that of the organic anions while H⁺ reflects that of the sulphate anion. Hydrogen ion concentration is always higher than that of sulphate in very colored waters, particularly during the summer months when organic anion concentrations are very high. Analysis of data in the tributaries in the Kejimkujik watersheds indicates that while considerable organic acidity is present in colored waters, anthropogenic sulphate further increases the free acidity of these waters, particularly at times of high discharge.     

An estimation of atmospheric deposition input of sulphur and nitrogen oxides to the Kejimkujik watershed : 1979–1987

Daily measurements of the concentrations of major ions in ambient air and in precipitation at Kejimkujik National Park, Nova Scotia, Canada over the period May 1979 to December 1987 are used to estimate the wet, dry and total deposition to the watershed. Variations on three time-scales are apparent. The strongest variation, of up to two orders of magnitude occurs on a day to day basis resulting in a coefficient of variation in the range of 110 to 140%. Deposition is highly episodic with the highest 20% of the daily events accounting for 55 to 60% of the long-term deposition. The most systematic variation is the annual cycle observed for many of the species. The air concentration of SO₂ has the most pronounced cycle with a winter maximum and a summer minimum. The SO _inf4 ^sup= air concentrations show a smaller amplitude and are out-of-phase with SO₂, showing a summer maximum. Air concentrations of HNO₃ and particulate N0 _inf3 ^sup- also have an out-of-phase annual cycle, with a summer maximum and summer minimum respectively. Wet deposition of SO _inf4 ^sup= shows a broad maximum through the summer months, but for NO _inf3 ^sup- no systematic cycle is evident. On an ion equivalent basis, NO _inf3 ^sup- contributes as much as SO _inf4 ^sup= to the acidity of winter precipitation, but only one-third as much in the summer months. Although 8.7 yr is too short a time-scale to establish long term variations with any certainty, there does appear to be an overall downward trend in S concentrations and deposition, but not for N. This is not inconsistent with the trends in the emissions of SO₂ and NO_X in the regions upwind of Nova Scotia. The fraction of the S input to the watershed as dry deposition is estimated to average 22% of the total.     

pH profiles from diatom stratigraphies in sediment cores of selected lakes of new brunswick and Nova Scotia,Canada

Diatom-inferred pH profiles have been constructed using the log x index for three lakes in Nova Scotia and four lakes in New Brunswick, Canada. The profiles cover the last 150 yr, including the past 70 to 80 yr when acid precipitation was increasing. The diatom-inferred pH changed from 6.1 to 5.3 for an unbuffered lake and from 6.3 to 6.1 for the buffered lake near Halifax, Nova Scotia, during the past 70 yr but no change in pH occurred in an unbuffered lake situated in the south of the province. Since 1900, the acidity of two unbuffered lakes in New Brunswick has changed from 6.5 to 6.1 and 6.2 to 5.7. There was no change in pH for the naturally-buffered lake and a third unbuffered lake in New Brunswick. The study suggests that there was a decline in pH of lake water in some unbuffered lakes of New Brunswick and Nova Scotia.     

Physical and chemical characteristics of three acidic,oligotrophic lakes and their watersheds in Kejimkujik National Park,Nova Scotia

Southwestern Nova Scotia receives acidic precipitation (average pH 4.5 to 4.6), and there are many waterbodies that are susceptible to acidification. This study characterizes the physical and chemical features of three remote, oligotrophic lakes and their watersheds in this region, in order to provide baseline information against which assessments can be made of changes caused by atmospheric depositions. Two of the lakes are small (<0.5 km²) and on headwater watersheds: Beaverskin Lake has an almost completely forested watershed and is moderately acidic and clear (pH 5.3, 5 Hazen units), while the watershed of Pebbleloggitch Lake is about 2/3 forested and 1/3 covered by a Sphagnum-heath bog, and its water is very acidic and highly colored (pH 4.3, 87 Hazen units). Kejimkujik Lake is much larger, its watershed is mostly forested but also contains some boggy terrain, its water is intermediate in acidity and color (pH 4.9, 65 Hazen units), and because it drains a much larger area of watershed it has relatively large concentrations of Ca, Mg, Na, Cl, and SO₄.     

Acid-base analysis of dissolved organic matter in surface waters

A mono-protic multi-site model is developed to obtain a pK(acid) — concentration distribution. Dense and equal interval pH data are required for an accurate characterization. A computer driven titrimetric system is used to obtain the data. The technique is applied to dissolved organic carbon (> 15 mg C L^-1) samples from the Kejimkujik region, Nova Scotia. A calculation shows that the acidic (pH=4.6) dystrophic waters can result from mixing 15 mg C L^-1 of the organic acids with an initial inorganic system of about 75 peq L^-1 alkalinity.     

Local patterns of sulphur deposition around Halifax/Dartmouth,Nova Scotia: 1979–83.

Five years of sampling support earlier findings that SO₂ emissions from Halifax/Dartmouth, Nova Scotia (population 270,000) cause wet sulphate deposition within 40 or 50 km of the city to be twice regional values. The urban effect is greatest within the city itself. Mean monthly sulphate concentrations in precipitation are usually more highly correlated among stations than is monthly deposition; the highest correlations are among concentrations in and around the city. Month to month variations in sulphate concentration in the city and at Oyster Pond (50 km east of the city) appear to be affected mainly by urban influences; those at St. Margaret's Bay (25 km west of the city) appear to be affected by both urban and regional influences. The urban effect appears to have diminished somewhat during the 5 yr, possibly because the urban emissions have decreased by 35% since 1980.     

Deposition around a coal-fired power station during a wintertime precipitation event

The contribution to local wet deposition of emissions from a coal-fired power station at Inkoo on the south coast of Finland has been investigated during a wintertime precipitation event. Making use of intensive radiosonde and weather radar observations of meteorological factors, concentrations of sulphur in deposition due to plume washout were predicted by a short-range deposition model. The model used the scavenging coefficient to parametrize the wet removal of pollutants, and it took into account the wind drift of falling precipitation particles within the plume. The model predictions were then compared with the chemical analysis results from snowfall samples collected within 10 km of the power station during the experiment.The experiment was performed ahead of a deeply-occluded front during a period with strong advection of long-range transported pollutants. No reliable sign of the influence of the power station on the sulphate deposition could be identified. On the other hand, the deviations of acidity from the mean pH-value of 4.1 were concentrated in one sector near the expected area of deposited plume pollutants. If local emissions were responsible for these deviations, the explanation may lie in a slightly incorrectly estimated plume direction or the effects of alkaline fly ash. Nevertheless, definite conclusions cannot be drawn, because only a few collectors happened to be sited in the modelled sector of plume washout and none in its maximum area.     

Vegetation,soils, and ion transfer through the forest canopy in two Nova Scotia lake basins

Characterization of the forest vegetation and soils in two adjacent; contrasting headwater lake basins located in Kejimkujik National Park, Nova Scotia was completed in 1980. Precipitation chemistry was studied during May to November, 1981–83 at two forested plots in each basin. There were 2012 stems ha^-1 in Beaverskin basin and 1816 stems ha^-1 in Pebbleloggitch basin. Beaverskin species composition was predominantly coniferous (72% of stems) while Pebbleloggitch was predominantly deciduous (52% of stems). Thickness and mass of organic soil layers were greater in Beaverskin. Mineral soil cation concentrations were similar. There were no differences between the basins in mean incident bulk precipitation pH. Mean volume-weighted pH for the period (73 collections) was 4.80. Sixteen percent of collections had a pH < 4.25. Sulphate deposition in incident bulk precipitation (May – November) ranged from 5.4–8.5 kg ha^-1 during 1981–83 while NO _inf3 ^sup- ranged from 0.04–0.93 kg ha^-1. The partitioning of incident precipitation into throughfall varied considerably (69%–38%) year-to-year. Temporal flux of ions did not differ significantly. Amounts of all major ions in throughfall especially SO _inf4 ^sup2- and base cations(Ca²⁺ + Mg²⁺ + K⁺ + Na⁺) were enriched.     

Determination and Mapping Critical Loads of Acidity and Exceedances for Upland Forest Soils in Eastern Canada

Critical loads of acidity were estimated for upland forests in Eastern Canada using the steady-state Simple Mass Balance (SMB) Model. A consistent methodology was applied to the entire region, although critical loads were estimated separately for the Atlantic provinces (New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland), Quebec and Ontario using different data sources. In this project, critical load estimates and steady-state exceedance values did not include the effect of forest fire and forest harvesting, which could have a considerable impact on critical loads in Eastern Canada. The observed soil pH – base saturation relationship for forest soils indicated that the constants used into the calculation of alkalinity leaching should be set to 10 (M/M) for the molar Bc/Al ratio in soil leachate and 10⁹ (mol L^?1)² for the gibbsite dissolution constant. The area-weighted median critical load for each province varied between 519 (Quebec) and 2063 eq ha^?1 y^?1 (Prince Edward Island), with a median critical load value for Eastern Canada of 559 eq ha^?1 y^?1. It is estimated that approximately 52% of the mapped area is exceeded in terms of acidity according to the 1994–1998 average total (wet + dry) atmospheric deposition. Greatest exceedances occurred in Ontario and Quebec and in the south of Nova Scotia, due to low critical loads and high loads of acid deposition.     

The effects of the emissions of the Kostomuksha mining complex on the chemical composition of deposition and soil water in the surrounding pine forests

The Kostomuksha mining complex in Russian Karelia is a major emission point source surrounded by large forest areas near the Finnish border. The sulphur dioxide emissions of the complex are almost 60 000 tonnes and dust emissions about 5 000 tonnes a year. Research into the effects of emissions on the surrounding forests were started in a Finnish-Russian co-operation project in 1992. Deposition measurements during the two first years indicate that the effects of the emissions extend about 30 km to the west of the complex. The annual sulphur deposition near the mining complex has been about 300 mg/m² in bulk precipitation and about 500 mg/m² in throughfall. Sulphur emissions sometimes extend the eastern parts of Finland, but there the deposition is clearly smaller than near to the mining complex. The high calcium emissions neutralize the acidifying effect of sulphur near to the mine and smelter. The iron concentration in precipitation also increased near the complex. Sulphur and calcium decreased in percolation water on moving westwards.     

Population genetic structure of a disjunct population of Blanding’s turtle (Emydoidea blandingii) in Nova Scotia, Canada

The Nova Scotia population of Blanding’s turtle (Emydoidea blandingii) is small and disjunct but surprisingly contains spatial structure. In this paper we explore the nature of that structure and attempt to identify the processes underlying it. Recent studies of the species in Nova Scotia have identified three discrete groups in what was previously thought to be a single panmictic population. There is no evidence of current movement between these groups. One group, at Kejimkujik National Park and National Historic Site, is restricted to the Mersey watershed; the other two groups are on the adjacent Medway watershed. The lack of current movement led to the prediction that there might be measurable genetic structure among these groups. Microsatellite analysis of five loci revealed significant genetic structure (F_ST = 0.042-0.124; p < 0.05) in pairwise comparisons between groups. Distance rather than watershed appears to be the principal determinant of spatial structure. Two separate analyses reveal no evidence of recent population bottlenecks. Population simulations suggest that this differentiation likely pre-dated human influence on the local landscape. In the face of rapid environmental change, understanding spatial structure in this population complex is essential so that we can match management scale to ecological scale in this long-lived, late maturing species.