Acid deposition and effects in Nordic Europe. Damage to fish populations in Scandinavia continue to apace

Although the decline in fish populations due to acidicwater in Norway started as early as in the 1920's the most rapid losses appeared during the 1960–70's. Until 1978, the populations of Atlantic salmon had disappeared from the southernmost part of Norway, and in these areas, more than half of the brown trout populations had been lost. Today, in spite of no increase in acid depositions, the fishery problems seems to continue at the same speed. Data based on interviews of the local fish authority shows that lakes still holding a fish population in the late 70's, have experienced a 30% loss of brown trout populations and a 12% loss of perch in the period 1978–1983. This trend have been confirmed by testfishing in lake systems having long data series. Salmon rivers on the western coast of Norway have experienced several episodes of fish kills due to rapid changes in water quality. These fish kills have mainly affected smolts of Atlantic salmon. Spawning migrating salmon on entering their acidified home river have also been affected. In Sweden, several salmon populations along the western coast have been lost due to acidification with no positive trends so far in the 1980's. Areas in central Sweden and in some high mountain areas are still experiencing a continuous and increasing acidification with detrimental effects on invertebrates and fish. In Finland, an increase in acidic deposition during the last decades have occurred, leading to acidification in the most sensitive freshwater systems. Although some acidified freshwater lakes are reported to have lost their fish stocks, few data on fish population effects are available.     

INCREASING ROLE OF NITROGEN IN THE ACIDIFICATION OF SURFACE WATERS IN THE ADIRONDACK MOUNTAINS,NEW YORK

Assessments of the aquatic effects of acidic deposition have focused on sulfur, as have recent efforts to control the emissions of acidifying compounds. Nitrogen dynamics were excluded from most acidic deposition modeling studies because it was believed that terrestrial ecosystems strongly retain N and because modeling N is a more formidable task than modeling S due to the influence of complex biological processes on N cycling. Re-examination of available data for the Adirondack Mountains of New York suggests that N deposition may be contributing to both chronic and episodic acidification of freshwaters to a greater extent than is generally believed. Previous research concluded that N has played a limited role in acidification processes in these lakes, based on regional averages of chronic chemistry. However, it is now known that historic acidification responses have been spatially variable within the Adirondack Mountains and that the declines in lakewater pH have been less than previously believed. Lakewater NO₃ ^- concentrations are commonly in the range of 5 to 25 μeq L^-1 on a chronic basis in portions of the Adirondack region that have experienced significant chronic acidification. These NO₃ ^- concentrations correspond in magnitude to inferred historical acidification. Furthermore, the relative importance of NO₃ ^- as an agent of acidification increases dramatically during snowmelt when conditions are most toxic to fish. The consequence of not addressing N in formulating acidification recovery strategies for the Adirondacks includes the likelihood that we will overestimate the response of surface water to the mandated sulfur emissions reductions.     

Application of henriksen's ‘acidification indicator’ and ‘predictor nomograph’ to two adirondack lakes

During the period 1977–1980 we studied the effects of highly acidic precipitation (mean pH 4.1 to 4.2) on the chemistry of three Adirondack lakes: Woods Lake, Panther Lake, and Sagamore Lake. Two of these lakes (Woods and Panther) are enough like those lakes of southern Sweden and Norway studied by Henriksen that they should constitute a valid test of his ‘acidification indicator’ and ‘predictor homograph’. In our comparison we used data from weekly samples taken near the surface of the lakes during unstratified summer and fall conditions over a 3 yr period. The acidification indicator and predictor nomograph were developed using data from lake samples taken under similar conditions in Scandinavia. Our principal finding is that with regard to the empirical line of the acidification indicator (that Henriksen found separated data from lakes receiving precipitation greater or less than pH 4.6) and with the precipitation pH axis of the predictor nomograph, these two methods of evaluation are not directly applicable ‘as is’ to our lakes. The reason for this is that the chemistry of precipitation in the Adirondacks is significantly different from (and for) which the acidification indicator and predictor nomograph were developed. In the Adirondacks, acids other than H₂SO₄ play a much greater role in the overall acidity of the precipitation. This causes relationships between precipitation pH and lake chemistry in the two regions to be different.     

Chrysophyte scales in lake sediments provide evidence of recent acidification in two Quebec (Canada) lakes

Several lake surveys have indicated that many lakes in Quebec are sensitive to acidification, but no historical data are available to provide conclusive evidence of lake acidification. Paleolimnological studies can provide such evidence. Chrysophycean algal microfossils were analyzed from the sediments of Lake Bonneville and Lake Truite Rouge in Quebec. The chrysophyte flora in the study lakes was stable until 40 yr ago, but since then the taxa characteristic of acidic or slightly acidic waters increased in abundance. The study provides evidence of recent lake acidification in Quebec.     

An evaluation of New York state lake liming data and the application of models from Scandinavian lakes to Adirondack lakes

Limestone dissolution efficiencies and reacidification rates observed in ten small Adirondack Mountain lakes, treated in 1983 to 1984 as part of the Extensive Liming Study (ELS), were compared with Scandinavian model predictions of dissolution (Sverdrup and Bjerle, 1983), and reacidification (Wright, 1985). The standard deviation of predicted initial dissolution was 15.4% of the observed fraction of limestone dissolved. Model predictions of dissolution for the Scandinavian lakes were similarly within 8 to 14% of observed values. Further analysis of the ELS data indicated that of the dissolution model parameters, dose rate alone was the best predictor of initial dissolution efficiency. Dissolution rates declined exponentially with time to undetectable levels within 2 to 3 yr following treatment. Total limestone dissolution efficiencies were in the range of 17 to 59% for the ELS lakes, which are comparable to levels observed in Scandinavian treatments with similar limestone materials (26 to 64%). Analysis of data from other Adirondack lakes limed by private groups and the New York State Department of Environmental Conservation for fisheries management programs, yielded similar estimates of dissolution efficiency for calcite based materials (average 36%). However, some of these lakes which were treated with slaked lime [Ca(OH)₂], exhibited initial dissolution efficiencies approaching 100%. The simple two box dilution model of reacidification, satisfactorily predicted Ca loss rates in the ELS lakes, indicating the importance of hydrology (water retention time) as a factor controlling reacidification rates in these small, limed lakes. For the ELS lakes, the ratio of watershed area/lake volume satisfactorily predicted Ca loss rates (R² = 0.96) and this simplified empirical model was applied to other Adirondack lakes where inadequate water chemistry and hydrologic data were available to utilize the dilution model. Limed Adirondack lakes with mean water retention times less than 4 mo reacidified within 1 yr after treatment. Given the preponderance of acidified lakes in the Adirondack region with retention times less than this threshold value of 4 mo (approximately 80% of lakes <10 ha surface area), simple whole lake liming practices would not be adequate for maintaining water quality suitable for the support of viable fish populations in these lakes.     

Inter-regional comparison of patterns and trends in surface water acidification across the United States

Temporal trends in acid-base chemistry are reported for surface waters in 6 regions of the United States. The lakes and streams are low ANC, dilute systems, selected to represent acid-sensitive aquatic resources in the 6 regions. The predominant trends observed were decreases in lake and stream SO₄ ^2? concentrations in sites east of the Mississippi River, and increases in NO₃ ^? in the Adirondack lake and Catskill stream sites (both located in eastern New York State). Correlations of trend results from all sites with other factors indicated that trends in precipitation volume were highly correlated with the observed trend patterns. From the surface water trend results, three distinct clusters were identified that corresponded to three trend patterns: ‘dilution,’ ‘recovery,’ and ‘acidification.’ These were distributed across the LTM regions, with no particular geographic patterns.     

Assessment of the Extent to Which Intensively-studied Lakes are Representative of the Adirondack Region and Response to Future Changes in Acidic Deposition

Many lakes in the Adirondack Mountains, New York, have acidified over the past century due to acidic atmospheric deposition. More recently, most monitored lakes have shown signs of chemical recovery (increase in acid neutralizing capacity) as sulfur deposition levels have declined in response to the Clean Air Act and other emissions control legislation. We used measured and modeled trends in past lakewater acidification and projections of future recovery from acidification to extrapolate results from judgment samples of intensively studied lakes to the population of acid-sensitive Adirondack lakes. Simulations were developed for 70 watersheds using the Model of Acidification of Groundwater in Catchments (MAGIC) to classify lakes according to their sensitivity to change in atmospheric S and N deposition. MAGIC simulations suggested that the modeled Adirondack Long-Term Monitoring Project (ALTM) and Adirondack Effects Assessment Project (AEAP) lakes were largely among the lakes in the population that had acidified most between 1850 and 1990. Most of the modeled ALTM/AEAP lakes were within the top 36% of acid sensitivity, based on model projections of past acidification and future chemical recovery, compared with the 1,829 Adirondack lakes in EPA’s Environmental Monitoring and Assessment Program (EMAP) statistical frame. Results of this research will allow fuller utilization of data from on-going chemical and biological monitoring and process-level studies by providing a basis for regionalization of findings and developing/refining relationships among watershed characteristics, chemical change, and biological responses to changing levels of acidic deposition.     

A comparative regional analysis of the status of aquatic resources with respect to acid deposition

A national scale assessment of the effects of acid deposition on aquatic resources is currently unavailable for the United States. A more limited assessment has been performed in three potentially sensitive geographical regions the Adirondack Mountains of New York, the Southern Blue Ridge Province of North Carolina, Tennessee and Georgia, and the Upper Midwest of Minnesota, Wisconsin and Michigan. A series of questions organized the assessment, and historical and current data from each region were employed to address the questions. Where possible, independent data sets were used singly and in combination within a given case study area, to respond to the questions and to provide an estimate of confidence. Conclusions among regions were also compared. In general, the impact of acid deposition on aquatic resources is difficult to detect, but positive correlations between atmospheric deposition and effects do exist. Thus, there is evidence to suggest that acid deposition is at least partially responsible for the acidification of aquatic resources. The extent of acidification, however, varies from region to region. The Adirondacks appear to represent the region of greatest impact, but independent studies indicate that the area of acidified lakes is a small percentage of the total resource. Despite the observation of minimal damage, application of damage estimates from the Adirondacks to other regions would be inappropriate. Future Assessments will seek to predict the rate of acidification of watersheds with other regional characteristics under alternative loading scenarios.     

Biology and chemistry of three Pennsylvania lakes: Responses to acid precipitation

The biology and chemistry of three northeastern Pennsylvania lakes was studied from summer 1981 through summer 1983 to evaluate lakes with different sensitivities to acidification. At the acidified lake (total alkalinity ≤ 0.0 μeq L^?1) there were fewer phytoplankton and zooplankton species than at the moderately sensitive lakes. The most numerous plankton species in all three lakes are reportedly acid tolerant. Among the benthic macro- invertebrates (BMI) there were more acid tolerant Chironomidae at the acidified lake, but more acid intolerant Ephemeroptera and Mollusca and a higher wet weight at the least sensitive lake. There were no differences among the lakes' BMI mean total numbers or mean number of taxa. The fish community at the acidified lake was dominated by stunted Lepomis gibbosus, but L. machrochirous were most abundant in the other lakes. Principal component analysis suggested a shift in all three lakes over the sampling period toward combined lower pH, alkalinity, specific conductance, Ca and Mg and higher Al and Mn. Such chemical changes have been associated with acidification. The rate and extent of acidification appeared to be controlled by geological and hydrological characteristics of the drainage basins.     

Relationship Between Landscape Characteristics,History, and Lakewater Acidification in the Adirondack Mountains,New York

Interactions between acidic deposition and watershed characteristics were evaluated for a group of lakes in the Adirondack Mountains, New York. Landscape characteristics were compiled and examined relative to paleolimnological inferences of historical acidification. Results of estimates of acidification using the Model of Acidification of Groundwater in Catchments (MAGIC) and paleolimnological analysis were compared to physical, biological, and landscape change data, including such factors as watershed disturbance, logging, fire, and windthrow, to evaluate if inclusion of additional processes could improve model estimates. Results of bivariate and multivariate analysis confirmed that lakes that have experienced historical acidification tend to be those that receive relatively high amounts of precipitation and have short hydraulic residence times. These variables explained 58% of the diatom-inferred acidification. A combined model of long-term precipitation amount, hydraulic residence time, and recent blowdown accounted for 71% of the historic acidification in the Adirondacks. Lakes that have increased in pH since pre-industrial times tend to be those subject to substantial human disturbance and those that burned during major fires recorded after 1900. The magnitude of the discrepancy between MAGIC model and diatom-inferred hindcasts of acidification was not significantly correlated with any of the landscape change variables, suggesting that additional modifications to the MAGIC model to take into account landscape change are not likely to appreciably improve model performance.     

A review of the chemical record in lake sediment of energy related air pollution and its effects on lakes

Inter-lake variation in accumulation rates of energy-related elements is a function of gross sedimentation rate (sediment focusing), position on pollution gradients, and water chemistry. Accumulation rates of Pb in lake sediments from profundal area cores in the Adirondack Mountains of New York and northern New England range from 0.1 to 0.2 ug/cm²/y (pre-1800 A.D.) to as much as 2 μg/cm²/y (recent sediment). Rates increase from the late 1800's to nearly the present, in parallel. Accumulation rates for V remain at background values which range up to 0.5 ug/cm²/y and increase 5 to 10 × background in Adirondack Mountain lakes. Chronically acidic lakes have a subsurface maximum. Of these three metals, only Pb has elevated deposition rates in high elevation lakes in the Rocky Mountains of Colorado. Mining activity is believed responsible for the implied air pollution there.     

Response of lake trout (Salvelinus namaycush) and brook trout (S. fontinalis) to surface water acidification in Ontario

Netting surveys of lakes varying in pH (4.4–7.1) showed that lake trout (Salvelinus namaycush) populations fail to recruit at pH <5.5 and are lost from lakes with pH<5.2. Brook trout (S. fontinalis) were extirpated in lakes with pH <5.0. In regional chemical surveys of Ontario lakes, it was found that 2% of sampled brook trout lakes and 2.5% of lake trout lakes were acidified (alkalinity <0 uEq L^?1). Threshold pH levels determined from fisheries assessments were used to estimate that 1% of lake trout and brook trout populations have been lost due to acidification.     

Impact of New York state emission sources on class 1 areas

The ARL-ATAD (Air Resources Laboratory-Atmospheric Transport and Dispersion) Model is used to calculate trajectories of air parcels leaving New York City, Albany, and Buffalo airshed regions and terminating near Federally-mandated Class 1 areas in the Northeastern United States, for which visibility is protected from degradation under the Clean Air Act. The purpose of this study is to provide an estimate of the frequency of occurrence of trajectory end points terminating over or near these environmentally sensitive regions from data for a one year period. Results indicate that these regions are not substantially effected by the air parcels either on an annual or seasonal basis.     

Cooperative federal-state liming research on surface waters impacted by acidic deposition

In the eastern and north-central United States, lakes and streams with low acid neutralizing capacity are at risk from acidity. Resource management agencies are interested in developing mitigation strategies that protect or restore fisheries in these waters. Addition of limestone (calcium carbonate) to improve water quality and prevent episodic depressions of pH during precipitation events and spring runoff is one mitigation technique being used. The ecological changes that accompany such treatment of streams and lakes are being investigated in a cooperative program between the U.S. Fish and Wildlife Service and individual states. Streams in Massachusetts, West Virginia and Tennessee, and a lake in Minnesota are included in this 5-yr research program. Intensive monitoring during pre- and post-liming tracks a suite of physical, chemical and biological parameters that influence the re-establishment or maintenance of healthy fisheries. Supporting studies on liming being conducted at Adirondack lakes in New York focus on fisheries management. A model on the influence of liming on light attenuation and thermal stratification is also being developed. Management guidelines are to be generated from the program results.     

The role of dissolved organic carbon in the chemistry and bioavailability of mercury in remote Adirondack lakes

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 through a field study and application of the Mercury Cycling Model (MCM). Concentrations of total Hg and total MeHg were highly variable, with concentrations of total MeHg about 10% of total Hg in lakes which did not show anoxic conditions. In lakes exhibiting anoxic conditions in the hypolimnion during summer stratification, concentrations of total MeHg were elevated. Concentrations of total Hg and total MeHg increased with decreasing pH in remote Adirondack lakes. However, more importantly, concentrations of total Hg and total MeHg increased with increasing concentrations of dissolved organic carbon (DOC) and percent near-shore wetlands in the drainage basin. Mercury concentrations in muscle tissue of yellow perch from Adirondack lakes were elevated above the U.S. FDA action level (1 μg/g Hg) in 7% of the fish sampled or in one or more individual fish from 9 of the 16 lakes sampled. Fish Hg concentrations generally increased with increasing fish length, weight and age. Patterns of increasing Hg concentration with age likely reflect shifts in prey of yellow perch and the bioconcentration of Hg along the food chain. For age 3 to 5 perch, concentrations of Hg increased with increasing concentrations of DOC and percent near-shore wetlands in the drainage basin. However, for a lake with very high DOC concentrations, fish concentrations of Hg declined. Calculations with the MCM also show that concentrations of Hg species increase with increasing DOC due to complexation reactions. Increases in DOC result in increasing concentrations of Hg in biota but decreases in the bioconcentration factor of Hg in fish tissue. This research suggests that DOC is important in the transport of Hg to lake systems. High concentrations of DOC may complex MeHg, diminishing its bioavailability. At high concentrations of monomeric Al, the complexation of MeHg with DOC apparently decreases, enhancing the bioavailability of MeHg.     

Regional chemical characteristics of lakes in North America: Part I — Eastern Canada

Data defining the major ion chemistry of lakes located in eastern Canada have been compiled for the purpose of evaluating the current status of surface water quality in relation to acidic deposition. A companion paper for lakes in the eastern United States (i.e. Part II, Linthurst et al., 1986) has been prepared also. Data sources in Canada included the National Inventory Survey, the Ontario Lake Sensitivity data set, and the National Aquatic Data base which provided an overall data base of approximately 5700 lakes. Only recently collected data (largely 1980 or later) were used in the analysis. Frequency distribution statistics were obtained for pH, acid neutralizing capacity (ANC), SO₄ and organic anion (A^?) concentrations. Acidic and low ANC waters in eastern Canada occur in a pattern explained by a combination of biogeochemical factors and atmospheric deposition. Nova Scotia contained the highest proportion of acidic and ultralow ANC lakes of any region surveyed in eastern North America; since this region receives approximately 20 kg.ha^?1.yr^?1 wet SO₄ deposition, the proposed target loading may be too high to protect the highly sensitive waters of Maritime Canada. Compared to the rest of eastern Canada, lakes in Ontario have relatively high ANCs due to the influence of CaCO₃ contained in the glacial till of the area. Variation in the SO₄ concentration of lakes approximately follows expected gradients in wet SO₄ deposition. Naturally occurring organic acids do not play a dominating role in the acidification of eastern Canadian lakes.     

A Comparison of the Temporally Integrated Monitoring of Ecosystems and Adirondack Long-Term Monitoring Programs in the Adirondack Mountain Region of New York

This paper compares lake chemistry in the Adirondack region of New York measured by the Temporally Integrated Monitoring of Ecosystems (TIME) and Adirondack Long-Term Monitoring (ALTM) programs by examining the data from six lakes common to both programs. Both programs were initiated in the early 1990s to track the efficacy of emission reduction policies and to assess the full impacts of acid deposition on surface water chemistry. They now serve to inform on the emerging chemical recovery of these waters. The Adirondack TIME program utilizes a probability-based approach to assess chronic acidification in a population of lakes using one summer sample per year. The ALTM attempts to track changes in both chronic and episodic acidification across a gradient of lake types using monthly samples. The ALTM project has two important attributes that contrast with the TIME program in the Adirondacks: higher temporal resolution (monthly versus once during the summer or fall) and speciation of aluminum. In particular, the ALTM program provides inorganic monomeric aluminum (Al_IM), the fraction of Al that is most toxic. The monthly sampling of the ALTM program includes the spring snowmelt period when acid-neutralizing capacity and pH are near their lowest and Al levels are near their highest. We compare chemistry trends (1992?C2008) for sulfate, nitrate, base cations, dissolved organic carbon, hydrogen ion, acid neutralizing capacity, and Al for the six lakes common to both programs. We also compare relatively high springtime Al_IM concentrations from the ALTM with relatively low summertime total Al concentrations from the TIME, showing that the ALTM program provides a more biologically relevant indicator of the effects of acid deposition, illustrating the value of the complementary monitoring efforts in the Adirondack region.     

Fish responses to acidity in Québec lakes: A review

To establish the impact of acidity on fish populations,studies were conducted in 37 Québec lakes located in four regions; the réserve des Laurentides and Portneuf and the Charlevoix and Témiscamingue regions. Density (catch per unit effort) of brook chary (Salvelinus fontinalis) decreases with increasing acidity. Moreover, in the Charlevoix region, this species has disappeared from three acid lakes (4.6 ?pH?5.l) with low Ca levels. Unlike growth, condition demonstrates a close relationship to acidity in brook charr populations. The total Al concentration in gills decreases with increasing size and pH. Lake acidity and sensitivity to acidification introduces problems in gamefish management. A survey of 17 lakes of the Témiscamingue region reveals that species diversity and total fish biomass are much lower in acid lakes than non acid lakes. In addition, two acid lakes are devoid of fish. Cyprinidae and Johnny darters (Etheostoma nigrum) are abundant in lakes with a pH level of 5.9 to 7.0 but are absent in lakes with a pH lower than 5.2. The yellow perch (Perca flavescens) is the only fish that appears to be tolerant to a wide pH range. This species, however, is in poor condition in acid lakes as compared with non acid lakes.     

Anthropogenic trace elements and polycyclic aromatic hydrocarbon levels in sediment cores from two lakes in the Adirondack acid lake region

Sediment cores were taken from the remote Sagamore and Woods Lakes in New York State's Adirondack acid lake region and analyzed for 3 to 7 ring polycyclic aromatic hydrocarbons (PAHs) and Ag, Al, As, Be, Cd, Cr, Cu, Hg, Ni, Ph, Se, Sn, TI, V, and Zn. With the exception of perylene, all of the parental PAHs, e.g. those without sidechains, and several of the metals, Pb, As, and Cd, were found to be significantly increased in the sediments of both lakes compared to their natural integrated deposits (ng cm^?2) and their background concentrations (μg g^?1 or ng g^?1 dry wt). Although the concentrations were generally much higher in Woods Lake, the total anthropogenic integrated depositions were about the same in both lakes for most of the metals and the 3 to 4 ring PAHs. The prime source of most of the 3 to 7 ring PAHs and trace elements measured is ascribed to anthropogenic combustion. Anthropogenically derived materials decreased in concentration with depth to baseline levels in sediment layers estimated by¹³⁷Cs analyses to be ～30 yr old, while biogenic or crustal derived species remained constant or fluctuated with core depth.     

Long-term trends in the chemistry of precipitation and lake water in the Adirondack Region of New York,USA

Long-term changes in the chemistry of precipitation (1978–94) and 16 lakes (1982–94) were investigated in the Adirondack region of New York, USA. Time-series analysis showed that concentrations of SO₄ ^2–, NO₃ ^–, NH₄ ⁺ and basic cations have decreased in precipitation, resulting in increases in pH. A relatively uniform rate of decline in SO₄ ^2– concentrations in lakes across the region (1.81±0.35 eq L^–1 yr^–1) suggests that this change was due to decreases in atmospheric deposition. The decrease in lake SO₄ ^2– was considerably less than the rate of decline anticipated from atmospheric deposition. This discrepancy may be due to release of previously deposited SO₄ ^2– from soil, thereby delaying the recovery of lake water acidity. Despite the marked declines in concentrations of SO₄ ^2– in Adirondack lakes, there has been no systematic increase in pH and ANC. The decline in SO₄ ^2– has corresponded with a near stoichiometric decrease in concentrations of basic cations in low ANC lakes. A pattern of increasing NO₃ ^– concentrations that was evident in lakes across the region during the 1980's has been followed by a period of lower concentrations. Currently there are no significant trends in NO₃ ^– concentrations in Adirondack lakes.