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.     

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.     

Mercury in the surface water of Swedish forest lakes —concentrations,speciation and controlling factors

Concentrations of total Hg and five operationally defined Hg species were determined in the surface water of 25 Swedish forest lakes of different type. Regional and seasonal variations were studied during the ice-free season of 1986. The concentration of total Hg was usually in the range of 2 to 10 μg m-3. Hg concentrations were highly correlated to the concentration of humic matter measured as water color. Hg concentrations were about twice as high in acidic lakes (pH 5) than in circumneutral lakes, which is attributed basically to the acidity of humic compounds acting as Hg carriers in boreal waters. Significant seasonal variations were caused by hydrological processes. During periods of high water flow, Hg concentrations increased dramatically, especially in humic lakes. Between spring and autumn, chemically reactive Hg compounds were gradually replaced by more inert species. Hg/C ratios were higher than in surface runoff from forest watersheds, indicating a significant impact of direct deposition of Hg on lake surfaces during summer. Regional differences were small despite differences in Hg contamination.     

Aluminium speciation; effects of sample storage

Effects of storage on surface waters fractionated for labile and non-labile aluminium (Al) were investigated. Water samples were collected from streams at two occasions; low and high flow respectively representing in varying concentrations of Al, organic substances and pH. Aluminium was measured as total monomeric Al and non-labile monomeric Al by the colourimetric reaction of pyrocatechol violet (PCV) combined with cation exchange using continuous flow analysis. The potentially toxic fraction, labile Al, can be calculated as the difference between total monomeric and non-labile monomeric Al.The samples were stored at 4 ± 2°C and the Al-fractions and pH were determined at several times during one to two months. The results indicate that the effects of sample storage were fairly small in stable low-flow waters with pH 6–8, but larger in unbalanced high-flow waters with pH 4–7, especially for the distribution of non-labile and labile monomeric Al.     

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.     

Chemical effects of spring and summer alum additions to a small,Northwestern Ontario Lake

Aluminum was added as aluminum sulfate (alum) to Lake 114, a small, shallow lake of the Experimental Lakes Area, northwestern Ontario, in spring and summer point-source additions. Aluminum and H⁺ gradients were established during the additions, with high Al and low pH (about 1000 μg L^?1 Al, pH 4.7) near the alum sources, and background conditions (< 50 μg L^?1 Al, pH 5.7) further from the sources. Approximately 80% of the added Al was lost from the water column in two weeks. Phosphorus concentrations remained unchanged during the additions, whereas lake alkalinity decreased and sulfate increased close to the sources. Dissolved organic carbon (DOC) concentrations decreased slightly (from 540 μM L^?1 to about 500 μM L^?1) near the alum source during the summer addition.     

Responses of atlantic salmon (Salmo salar) alevins to dissolved organic carbon and dissolved aluminum at low pH

Mortality of Atlantic salmon alevins in solutions containing Al and dissolved organic anions (both synthetic and natural) was correlated with Al accumulation in alevin tissues. Both mortality and accumulation could be related to the concentration differences between Al and organic anions. Mortality and body accumulation of Al both increased dramatically as total Al concentrations increasingly exceeded organic anion concentrations. Alevin growth and yolk utilization were both less rapid at inorganic monomeric Al concentrations exceeding 2 μM (50 μg L^-1). The acidic fractions of dissolved organic matter (DOM) are more effective in protecting alevins against Al toxicity than are the neutral and basic fractions. Ambient inorganic monomeric Al is probably not toxic to salmon alevins in acidic Nova Scotian streams, even during snow-melt.     

Influence of Acidification and Liming on the Distribution of Trace Elements in Surface Waters

Metals in water have been monitored for up to 18 years in acidified regions of Sweden. The concentrations of metals (Al, Cd, Cu, Fe, Mn, Mo, Pb, Zn) were determined by AAS and ICP-MS, the dissolved fractions after separation by in-situ dialysis. Elements showing negative pH-correlation were primarily Al, Zn, Cd, Mn, and Pb, while Mo was positively correlated to pH, indicating a predominance of negatively charged ionic forms. Zn, Cd, and Mn occurred primarily in the dissolved fractions, especially at the lower pH levels. Fe, Al, Pb and Mn were further enriched in humic waters. During the study period, some of the sites were subject to lime treatment, which had a marked influence on most elements, causing the mean levels and the seasonal fluctuations to decrease. Treatment on the lake surface was less effective than wetland liming to reduce seasonal fluctuations, especially for metals mainly originating from the catchments, as Fe and Al.     

Hydrologic pathways and chemical composition of runoff during snowmelt in Loch Vale Watershed,Rocky Mountain National Park,Colorado, USA

Intensive sampling of a stream draining an alpine-subalpine basin revealed that depressions in pH and acid neutralizing capacity (ANC) of surface water at the beginning of the spring snowmelt in 1987 and 1988 were not accompanied by increases in strong acid anions, and that surface waters did not become acidic (ANC<0). Samples of meltwater collected at the base of the snowpack in 1987 were acidic and exhibited distinct ‘pulses’ of nitrate and sulfate. Solutions collected with lysimeters in forest soils adjacent to the stream revealed high levels of dissolved organic carbon (DOC) and total Al. Peaks in concentration of DOC, Al, and nutrient species in the stream samples indicate a flush of soil solution into the surface water at the beginning of the melt. Infiltration of meltwater into soils and spatial heterogeneity in the timing of melting across the basin prevented stream and lake waters from becoming acidic.     

The influence of land management on concentrations of dissolved organic carbon and its effects on the mobilization of aluminium and iron in podzol soils in Mid-Wales

Abstract. The aluminium (Al), iron (Fe) and Dissolved Organic Carbon (DOC) contents of the soil solution were monitored in two upland grassland and afforested podzol soils in Mid-Wales. Al organo-metallic complexes predominated in the O horizon leachates of the grassland soil, whereas inorganic monomeric Al forms dominated in the lower mineral horizons. Dissolved organic matter determines the chemistry, solubility, and transport of Al and Fe in the O horizon, and these are under strong biological control. The distributions of organic-Al, Fe and DOC within the soil profile were consistent with traditional podzolization theory. Observed increases in the molar ratios of Al:DOC in solution in the lower soil horizons may be responsible for the small solubility of Al organo-metallic complexes in those horizons. Afforestation increased the concentrations of organic-Al and Fe in the soil solution as compared with the concentrations observed for the grassland soil. Clearcutting further significantly mobilized Al and Fe from the upper soil horizon, primarily by increasing the DOC concentration in the soil water.     

The involvement of iron and aluminum in the bonding of phosphorus to soil humic acid

Abstract

With a peat soil similar amounts of phosphorus (P) were coprecipitated with humic acid from alkali extracts over a limited range of strongly acidic pH, whereas with a mineral soil the amount was pH dependent. The difference between the two soils relates to the much greater total amounts of inorganic P and aluminum (Al) present in the extract of the mineral soil. In this acid mineral soil, Al rather than iron (Fe) may be involved in the formation of metal bridges in humic acid‐metal‐inorganic P complexes. Neither Al or Fe were implicated in binding of organic P to humic acid. The P species observed in humic acids was dependent on the pH at which they were precipitated from the alkali extracts. In the peat soil the inorganic P was an order of magnitude lower than the organic P.     

Geochemical Mobility and Bioavailability of Heavy Metals in a Lake Affected by Acid Mine Drainage: Lake Hope, Vinton County, Ohio

Sandy Run (Vinton County, southeastern Ohio, USA) is a stream receiving acid mine drainage (AMD) from an abandoned coal mine complex. This stream has been dammed to form Lake Hope. The heavy metal composition of waters (benthic and pore), sediments, and macroinvertebrates in the lake reservoir sediments were analyzed. Lake waters contained Mn as the heavy metal present in higher concentrations followed by Fe, Al, and Zn. Depletion of Fe and Al occurred from precipitation of less soluble Fe and Al oxides and hydroxides along Sandy Run before entering the lake, producing a high Mn water input into the reservoir. Concentrations of heavy metals in the sediments increased toward the dam area. Sequential extraction of metals in the sediments showed that the highest fractions of metals corresponded to the detrital fraction or eroded material from the watershed and metals associated with iron and manganese hydroxides. Heavy metals in the organic sediment fraction were low. Heavy metals from the AMD source, as well as sediments rich in heavy metals eroded from the watershed, were transported to the downstream dam area and stored at the bottom, producing the observed chemistry. Heavy metals in benthic waters also were sourced from the diffusion of ions from sediments and lake waters as variation in pH and redox conditions determined the flux at the sediment–water interface. Metal concentrations were measured within two deposit feeders, oligochaetes and chironomids, and compared to trends in physical metal concentration across the lake. For the four heavy metals with higher concentration in both benthic animals, the concentrations followed the trend: Fe?>?Al?>?Mn?>?Zn, which were similar to the bioavailable metals in the sediments rather than the pore or the benthic water where Mn was the most abundant heavy metal. Ingestion of sediment, not exposure to pore or benthic waters, appeared to be the main transfer mechanism for metals into the biota. Trends and patterns in animal metal concentrations across the lake were probably a complex process controlled by metabolic needs and metallic regulation and tolerance. Even when Mn was the highest concentration heavy metal in the pore waters, it was the lowest to bioconcentrate in the organisms. In comparison, Cd, the lowest concentration metal in the sediments, presented one of the highest bioaccumulation factors.     

Metal concentration in the gill,gastrointestinal tract,and carcass of white suckers (Catostomus commersoni) in relation to lake acidity

Adult white suckers were collected from four lakes in Maine that ranged in pH from 7.0 to 5.4. The gastrointestinal tract and remainder of the carcass of fishes of similar age and size from each lake, and gills from additional fishes of similar size, were analyzed for Al, Cd, Pb, and Zn. Carcasses were also analyzed for Hg. Concentrations of Al, Cd, and Pb were highest in the gastrointestinal tract and lowest in the carcass; Zn concentration was highest in the gill. For carcass, all metals except Al differed significantly among lakes, for gill tissue Cd and Pb differed, and for gastrointestinal tract, only Cd differed among lakes. Where differences were significant, patterns among lakes were similar in each tissue analyzed. Concentrations of Cd, Hg, and Pb were negatively correlated with lake water pH, acid neutralizing capacity (ANC), Ca, and lake:watershed area, and positively correlated with lake water SO₄, indicating that concentrations were higher in fish from more acidic lakes. Zinc concentrations in gills were unrelated to lake acidity, and carcass concentrations were higher in the less acidic lakes, which is the opposite of the pattern for the other metals studied. Zinc in gastrointestinal tract did not differ among lakes. Although the lakes we studied were located in undisturbed watersheds and did not receive any point source discharges, fish metal concentrations were comparable to or higher than those reported from waters receiving industrial discharges.     

Effects of forest age on surface drainage water and soil solution aluminium chemistry in stagnopodzols in Wales

The influence of forest development on soil solution and surface drainage water aluminium chemistry was investigated in Sitka spruce (Picea sitchensis) plantations in Wales. Comparisons with semi-natural grassland and moorland sites are described. A highly significant positive relationship was shown between increasing forest age and soilwater aluminium concentrations in the B horizons. Shortterm/episodic peaks in Al concentrations were strongly related to incidences of high concentrations of neutral, marine-derived, salts in the soilwater. Nitrification may be an important factor in soil acidification and the mobilization of Al in soilwaters beneath the older mature-forest plantations in Wales. Labile monomeric Al concentrations were largest in surface waters draining the oldest forestry plantations compared with younger forest catchments and moorland, although response to discharge of soilwater acidity to the surface waters at individual sites was dependent on the acid neutralizing capacity of the groundwater component of the surface waters.     

Aluminium precipitates formed downstream of springs in a mountainous environment

Areas a few square metres in size, devoid of higher vegetation other than moss, have been mapped at 600–700 m above sea level in the mountains of the western part of central Norway. The moss is covered by a grey precipitate during dry summer periods. The precipitate has been identified by ICP-AES analysis of HNO₃-extract, X-ray diffraction (XRD) and by scanning electron microscopy (SEM) as an aluminium(Al)-hydroxide, probably amorphous Al-hydroxide and diaspore (Al(OH)₃), containing 21–25% Al by weight. In comparison, the underlying moraine deposits contain 1.5–3.5% Al by weight. A small spring, where groundwater discharges, is located uphill of each contaminated area. The Al content of the water which emerges from these springs decreases downhill away from the spring and is inversely proportional to the pH. The runoff waters originating at the springs have been modelled using the computer-codes MINTEQA2 and ALCHEMI and are found to be saturated with respect to amorphous Al(OH)₃. This study raises the very important question as to what extent a lower pH in the influent meltwater may leach out more aluminium and possibly lead to the formation of larger amounts of precipitate.     

Mobilization of aluminium, iron and silicon by Picea abies and ectomycorrhizas in a forest soil

Weathering of soil minerals is a key determinant of ground and surface water quality and is also important in pedogenic and rhizosphere processes. The relative importance of biotic and abiotic studies in mineral weathering, however, is poorly understood. We investigated the impact of Picea abies seedlings, an ectomycorrhizal fungus and humic acid on the solubilization of aluminium (Al), iron (Fe) and silicon (Si) in an E horizon forest soil over 10 months. Elemental budgets were constructed based upon losses in drainage water, accumulation in plants and changes in the pools of exchangeable ions. Plants and mycorrhizas or both had a significant effect on the total amounts of Al, Fe and Si mobilized from the soil. Significantly larger amounts of Al and Fe were recovered in plants than those lost in drainage water, whereas the opposite trend was true for Si. The continual addition of dissolved organic matter to the soil in the form of humic acid had an effect only on mobilization of Fe, which increased due to larger plant uptake and an increase in the exchangeable pool. The mobilization of Fe and Si were positively correlated with hyphal length, soil respiration and concentrations of oxalate in the soil solution, and mobilization of Al was strongly correlated with plant weight. Scanning electron microscopy revealed that most fungal hyphae were associated with mineral surfaces with little occupation of cracks and micropores within mineral grains. Evidently ectomycorrhizas have important impacts on mineral dissolution and the chemistry of forest soils.     

Crystallization of single and binary iron‐ and aluminum hydroxides affect phosphorus desorption

In acidic soils, phosphorus availability is affected by its strong affinity for mineral surfaces, especially Fe‐ and Al‐hydroxides. Plant roots have developed adaptive strategies to enhance the availability of phosphorus, including producing and exuding low molecular weight organic acids with a high affinity for phosphorus that competes with high molecular weight organic ligands formed during humification and mineralization. The aim of this study was to characterize the kinetics and mechanism of phosphorus desorption from Fe‐ and Al‐hydroxides of variable crystallinity, as well as binary Fe:Al‐hydroxide mixtures. Long‐term desorption experiments (56 days) were conducted with CaCl₂, CaSO₄, citric acid, and humic acid as competitive sorptives. CaCl₂ and CaSO₄ were selected as general inorganic sorptives and citric and humic acids were selected as organic ligands produced by organisms in the rhizosphere or following humification. The cumulative phosphorus desorption increased following the order CaCl₂ < CaSO₄ < humic acid < citric acid. Amorphous ferrihydrite and Fe‐rich Fe:Al‐hydroxides exhibited much less desorption when exposed to inorganic solutions than the crystalline and Al‐rich Fe:Al‐hydroxide mixtures. Models of the desorption data suggest phosphorus desorption with citric acid is diffusion‐controlled for ferrihydrite and Fe‐rich amorphous Fe:Al‐hydroxides. When humic acid was the sorptive, metal‐organic complexes accumulated in the solution. The results suggest organic compounds, especially citric acid, are more important for liberating phosphorus from Fe‐ and Al‐minerals than inorganic ions present in the soil solution.     

施用碱稳定污泥污水土壤经γ-辐照后土壤溶液中Cu和Zn

Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminumions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al-OM) to total Al ranged from 7.7% to 69%, and that of the acid-soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al-OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al³⁺. The complexes of aluminum with fluoride (Al-F) were the predominant forms of inorganic Al, and the proportion of Al-F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al³⁺ was also a major form of inorganic Al, and the proportion of Al³⁺ to total inorganic Al decreased with increasing pH. The proportions of Al-OH and Al-SO₄ complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrat ions of Al-OM, Al³⁺, Al-F and Al-OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminumions were influenced by pH. The concentrations of Al-OM, Al³⁺, Al-F complexes and Al-OH complexes decreased with the increase in pH.     

Mercury speciation in Lake Baikal

Research on mercury (Hg) distribution and speciation was carried out in Lake Baikal, a large, strong-oligotrophic freshwater reservoir in Siberia, Russia, during June 1992 and march 1993. In summer, total Hg in the water column ranged from 0.14 to 0.77 ng Hg/L, with the highest concentrations observed in the central basin of the lake in surface water samples. Labile inorganic Hg was found to be 7 to 20 % of the total Hg content. Highest total Hg concentrations were found in river waters: up to 2 ng Hg/L. Labile methylmercury (MeHg) concentrations ranged from 2 to 38 pg Hg/L in the water column, with the higher concentrations in the central part of the lake, and showing a slight increase in near bottom waters. Labile MeHg makes up 1 to 15 % of the total Hg content in the water column, with larger fractions in deep waters. The slight increase of the MeHg gradient with depth corresponds with the O₂ minimum region. Highest MeHg concentrations were observed in river waters (up to 145 pg Hg/L) and in some bays of the lake (up to 160 pg Hg/L). In these high temperature- and phytoplankton-rich water masses, the MeHg-fraction increased up to 35 % of total Hg. Labile MeHg concentrations in water samples taken in winter in the southern basin (under the ice cover), showed slightly higher concentrations than in summer, possibly due to an early spring bloom. In rainwater, total Hg ranged from 3 to 20 ng Hg/L and MeHg from 0.1 to 0.25 ng Hg/L. In snow, a large fraction of total Hg is bound to particulate matter; concentrations of total Hg ranged from 8 to 60 ng Hg/L and labile MeHg from 0.1 to 0.25 ng Hg/L. Atmospheric Hg was found to be 0.73 to 2.31 ng/m³ as gaseous Hg and 0.005 to 0.02 ng/m³ in its particulate form. Spatial distribution patterns of atmospheric Hg show slightly higher concentrations over the central part of the lake and the Selenga river delta. In winter, atmospheric Hg values (measured in the southern region), ranged from 1.2 to 6.1 ng/m³ as total gaseous Hg and 0.02 to 0.09 ng/m³ as total particulate Hg, and are higher than in summer, probably influenced by coal burning and traffic by the local population. MeHg contents in fish ranged from 20 ng Hg/g dry weight in small Cottocomephorus to 300 ng Hg/g dry weight in pike and trout species, which were caught in organic-rich waters.     

The geochemistry of black water in selected coastal streams of the Southeastern United States

Abstract

An investigation was conducted in a watershed formed by the tributaries of the Little River in South Georgia to study the nature of the humic and inorganic fractions of black water, and their influence on stream water quality. Large amounts of black colored water were sampled during 1983 to 1984 according to streamflow pattern in December, March, June and September. Measurements of air and water temperature and dissolved oxygen were made at the gaging sites, whereas water analysis for conductivity, Cl, NO₃‐N, NH₄‐N, P, total N, and other macro‐ and microelements were conducted in the laboratory. Fulvic (FA) and humic acid (HA) were isolated from the water samples, and analyzed by infrared and ¹³C NMR spectroscopy. Suspended clay from the water samples were collected and determined by x‐ray diffraction analysis. The results showed that black water was characterized by low conductivity and low ion concentrations indicating satisfactory chemical quality. The Na content was half the amount of other rivers in the Southeastern United States, whereas the ? content was similar to the world average. A seasonal fluctuation was noticed for Ca and Mg concentration. The increase of these ions during high streamflow in spring and summer was attributed to agricultural practices in the surrounding lands. Dissolved organic matter (DOM) concentration was highest in December during low streamflow. As DOM content decreased during high streamflow, water pH increased. A large part of the humified DOM was composed of fulvic acid, which was more aromatic in nature than soil‐fulvic acid as determined by ¹³C NMR. The suspended clay had a composition reflecting the clay mineralogy of Tifton soils in the surrounding uplands. It is believed that the Tifton soil, with its low activity clay and hence low CEC, may not be able to buffer the effect of acid leaching of black water.