Exploratory Analysis of the Winter Chemistry of Five Lakes on the North Slope of Alaska1

Abstract: Lakes are important water resources on the North Slope of Alaska. Freshwater is required for oilfield production as well as exploration, which occurs largely on ice roads and pads. Since most North Slope lakes are shallow, the quantity and quality of the water under ice at the end of winter are important environmental management issues. Currently, water‐use permits are a function of the presence of overwintering fish populations, and their sensitivity to low oxygen concentrations. Sampling of five North Slope lakes during the winter of 2004‐2005 shed some light on the winter chemistry of four lakes that were used as water supplies and one undisturbed lake. Field analysis was conducted for oxygen, conductivity, pH, and temperature throughout the lake depth, as well as ice thickness and water depth. Water samples were retrieved from the lakes and analyzed for Na, Ca, K, Mg, Fe, dissolved‐organic carbon, and alkalinity in the laboratory. Lake properties, rather than pumping, were the best predictors of oxygen depletion, with the highest dissolved‐oxygen levels maintained in the lake with the lowest concentration of constituents. Volume weighted mean dissolved‐oxygen concentrations ranged from 4 to 94% of saturation in March. Dissolved oxygen and specific conductance data suggested that the lakes began to refresh in May.     

Chemical and Physical Controls on the Oxygen Regime of Ice‐Covered Arctic Lakes and Reservoirs1

Abstract: We examined the chemical, morphological, and anthropogenic controls on winter‐oxygen biogeochemistry in ice‐covered lakes and reservoirs on the North Slope of Alaska. We measured dissolved oxygen (DO), solute concentrations, water depth, and ice thickness at three natural thaw lakes and four reservoirs (flooded gravel mines) for two winters. In all seven study sites, DO concentration and pH decreased with depth, and temporally through the winter (November to April). DO concentration was four to six times greater in the deeper reservoirs (8‐13 mg/l) compared with shallow natural lakes (ca. 2 mg/l). Lakes and reservoirs with high dissolved organic carbon (DOC) concentration were susceptible to large decreases in oxygen over the winter. DO concentration differed markedly between years, but was not attributed to changes in water‐use or winter water‐chemistry. Alternatively, we suggest that dissolved oxygen concentration was lower during freeze‐up, possibly associated with higher lake‐productivity during the summer. Our results suggest that current water‐use practices on the North Slope of Alaska caused little to no change in DO concentration over the winter. In particular, considering the high pumping activity and shallow depth, lakes with low DOC concentration (≤6 mg/l) showed strong resilience to change in chemistry over the winter. We suggest that both lake and reservoir depth, and DOC concentration are key factors influencing oxygen consumption in ice‐covered arctic lakes and reservoirs.     

Long term changes in the eutrophication process in a shallow Mediterranean lake ecosystem of W. Greece: response after the reduction of external load

Lake Pamvotis is a shallow Mediterranean lake located in Western Greece near the city of Ioannina. The lake has been recognized as an internationally important conservation site under European Community legislation due to its rich biodiversity. However, during the last three decades the trophic status of the lake has changed as a result of anthropogenic activity (among others irrigation and domestic sewage discharge), resulting in serious problems. Here we present data about the long-term development in eutrophication of Lake Pamvotis. Water samples were collected and analyzed (water temperature, pH, dissolved oxygen, nutrients, chlorophyll-a) during three monitoring periods: 1985-1989, 1998-1999, 2004-2005. The high nutrient concentrations in the lake water during the three monitoring periods, as well as its eutrophic to hypertrophic status reflect the degree of impact anthropogenic activity has had on the lake. Commencement of a restoration plan in 1995-1996, involving sewage diversion, led to a reduction in external nutrient load and consequently to lower in-lake nutrients and Chlorophyll-a concentrations. Orthophosphate concentration decreased by about 87%, nitrates fell below 1.20mg/l, whilst the total reduction of inorganic N compounds showed a weaker downward trend, fluctuating between 0.39 and 1.24mg N/l with an average value of 0.76mg N/l. However, after a short-term recovery the eutrophic status of the lake remains eight years later (2004-2005), suggesting the importance of the internal loading process and the absence of the top-down effect of fish. This study provides evidence for the need of greater restoration efforts utilized in Mediterranean shallow lakes.     

Novel passive co-treatment of acid mine drainage and municipal wastewater

A laboratory-scale, four-stage continuous-flow reactor system was constructed to test the viability of high-strength acid mine drainage (AMD) and municipal wastewater (MWW) passive co-treatment. Synthetic AMD of pH 2.6 and acidity of 1870 mg L(-1) as CaCO3 equivalent containing a mean 46, 0.25, 2.0, 290, 55, 1.2, and 390 mg L(-1) of Al, As, Cd, Fe, Mn, Pb, and Zn, respectively, was added at a 1:2 ratio with raw MWW from the City of Norman, OK, to the system which had a total residence time of 6.6 d. During the 135-d experiment, dissolved Al, As, Cd, Fe, Mn, Pb, and Zn concentrations were consistently decreased by 99.8, 87.8, 97.7, 99.8, 13.9, 87.9, and 73.4%, respectively, pH increased to 6.79, and net acidic influent was converted to net alkaline effluent. At a wasting rate of 0.69% of total influent flow, the system produced sludge with total Al, As, Cd, Cr, Cu, Fe, Pb, and Zn concentrations at least an order of magnitude greater than the influent mix, which presents a metal reclamation opportunity. Results indicate that AMD and MWW passive co-treatment is a viable approach to use wastes as resources to improve water quality with minimal use of fossil fuels and refined materials.     

Cottongrass effects on trace elements in submersed mine tailings

Phytostabilization may limit the leakage of metals and As from submersed mine tailings, thus treatment of acid mine drainage with lime could be reduced. Tall cottongrass (Eriophorum angustifolium Honckeny) and white cottongrass (E. scheuchzeri Hoppe) were planted in pots with unlimed (pH 5.0) and limed (pH 10.9) tailings (containing sulfides) amended with sewage sludge (SS) or a bioashsewage sludge mixture (ASM). Effects of the amendments on plant growth and plant element uptake were studied. Also, effects of plant growth on elements (Cd, Cu, Pb, Zn, and As), pH, electrical conductivity (EC), and concentrations of SO4(2-), in the drainage water as well as dissolved oxygen in tailings, were measured. Both plant species grew better and the shoot element concentrations of white cottongrass were lower in SS than in ASM. Metal concentrations were lowest in drainage water from limed tailings, and plant establishment had little effect on metal release, except for an increase in Zn levels, even though SO4(2-) levels were increased. In unlimed tailings, plant growth increased SO4(2-) levels slightly; however, pH was increased and metal concentrations were low. Thus, metals were stabilized by plant uptake and high pH. Amendments or plants did not affect As levels in the drainage water from unlimed tailings. Thus, to reduce the use of lime for stabilizing metals, phytostabilization with tall cottongrass and white cottongrass on tailings is a sound possibility.     

VARIATION IN ADIRONDACK,NEW YORK,LAKEWATER CHEMISTRY AS FUNCTION OF SURFACE AREA1

ABSTRACT: Data from a recent survey conducted by the Adirondack Lake Survey Corporation were used to evaluate the influence of lake surface area on the acid-base status of lakes in Adirondack State Park, New York. Acid neutralizing capacity (ANC) in the small lakes (< 4 ha) occurred more frequently at extreme values (> 200, < 0 μeq L^?1), whereas larger lakes tended to be intermediate in ANC. Consequently, acidic (ANC ≤ 0) and low-pH lakes were typically small. The small lakes also exhibited lower Ca²⁺ concentration and higher dissolved organic carbon than did larger lakes. Lakes ≥ 4 ha were only half as likely to be acidic as were lakes ≥ 1 ha in area. These data illustrate the dependence of lake chemistry on lake surface area and the importance of the lower lake area limit for a statistical survey of lake water chemistry.     

Passive treatment of acid mine drainage in bioreactors using sulfate-reducing bacteria: critical review and research needs

Acid mine drainage (AMD), characterized by low pH and high concentrations of sulfate and heavy metals, is an important and widespread environmental problem related to the mining industry. Sulfate-reducing passive bioreactors have received much attention lately as promising biotechnologies for AMD treatment. They offer advantages such as high metal removal at low pH, stable sludge, very low operation costs, and minimal energy consumption. Sulfide precipitation is the desired mechanism of contaminant removal; however, many mechanisms including adsorption and precipitation of metal carbonates and hydroxides occur in passive bioreactors. The efficiency of sulfate-reducing passive bioreactors is sometimes limited because they rely on the activity of an anaerobic microflora [including sulfate-reducing bacteria (SRB)] which is controlled primarily by the reactive mixture composition. The most important mixture component is the organic carbon source. The performance of field bioreactors can also be limited by AMD load and metal toxicity. Several studies conducted to find the best mixture of natural organic substrates for SRB are reviewed. Moreover, critical parameters for design and long-term operation are discussed. Additional work needs to be done to properly assess the long-term efficiency of reactive mixtures and the metal removal mechanisms. Furthermore, metal speciation and ecotoxicological assessment of treated effluent from on-site passive bioreactors have yet to be performed.     

RELATIONS BETWEEN COLOR AND SOME LIMNOLOGICAL CHARACTERISTICS OF FLORIDA LAKES1

Data obtained from a limnological survey of 165 Florida lakes were analyzed to determine regional differences in lake color (Pt-Co units) and relations between color and various physical, chemical, and biological parameters. Average color measurements for the different lakes ranged from 0 to 416 Pt-Co units with individual measurements being as high as 600 Pt-Co units. With the exception of extreme south Florida, lake color concentrations were found to increase from north to south and from inland highlands to lowlands. Central Florida had the greatest heterogeneity in lake color because of an extremely diverse geology and physiography. Color was inversely related to Secchi disc transparency and positively related to total iron concentrations. Color was not strongly related to pH, total alkalinity, nutrients, chlorophyll a, and many other limnological parameters. Although lakes having color concentrations greater than 20 Pt-Co units can often be visually identified as colored lakes, the limnological processes in these are not necessarily different from those of lakes having clear water.     

Effects of wood bark and fertilizer amendment on trace element mobility in mine soils, Broken Hill, Australia: implications for mined land reclamation

Soil amendments can immobilize metals in soils, reducing the risks of metal exposure and associated impacts to flora, fauna and human health. In this study, soil amendments were compared, based on "closed system" water extracts, for reducing metal mobility in metal-contaminated soil from the Broken Hill mining center, Australia. Phosphatefertilizer (bovine bone meal, superphosphate, triple superphosphate, potassium orthophosphate) and pine bark (Pinus radiata) were applied to two soils (BH1, BH2) contaminated with mining waste. Both soils had near neutral to alkaline pH values, were sulfide- or sulfate-rich, and contained metal and metalloid at concentrations that pose high environmental risks (e.g., Pb = 1.25 wt% and 0.55 wt%, Zn = 0.71 wt% and 0.47 wt% for BH1 and BH2, respectively). The addition of fertilizers and/or pine bark to both soil types increased water extractable metals and metalloids concentrations (As, Cd, Cu, Fe, Mn, Pb, Sb, Zn) compared with nonamended soils. One or more of the elements As, Cd, Cu, Mn, Pb, and Zn increased significantly in extracts of a range of different soil+pine bark and soil+fertilizer+piner+pine bark tests in response to increased pine bark doses. By contrast, Fe and Sb concentrations in extracts did not change significantly with pine bark addition. Solution pH was decreased by phosphate fertilizers (except for bovine bone meal) and pine bark, and pine bark enhanced dissolved organic carbon. At least in the short-term, the application of phosphate fertilizers and pine bark proved to be an ineffective method for controlling metal and metalloid mobility in soils that contain admixtures of polymetallic, polymineralic mine wastes.     

Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines in Alberta, Canada

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational “put and take” fisheries.     

Metal release from bottom sediments of Ocoee Lake No. 3, a primary catchment area for the Ducktown Mining District

Ocoee Lake No. 3 is the first reservoir receiving suspended sediments contaminated with trace metals discharged by acid mine effluents from the Ducktown Mining District, Tennessee. Bottom sediments (0-5 cm) from the lake were sampled to assess the potential for future adverse environmental effects if no remediation controls or activities are implemented. The sediments were found to include a major component (173 +/- 19 g kg(-1)) that dissolved in 6 mol L(-1) HCl within 24 h. This acid-soluble and relatively labile fraction contained high concentrations of Fe (460 +/- 40 g kg(-1)), Al (99 +/- 11 g kg(-1)), Mn (10 +/- 8 g kg(-1)), Cu (2000 +/- 700 mg kg(-1)), Zn (1300 +/- 200 mg kg(-1)), and Pb (300 +/- 200 mg kg(-1)). When the pH of water in contact with the sediment was decreased experimentally from 6.4 to 2.6, the concentrations of dissolved trace metals increased by factors of 2200 for Pb, 160 for Cu, 21 for Zn, 9 for Cd, 8 for Ni, and 5 for Co. The order in which metals were released with decreasing pH was the reverse of that reported for pH-dependent sorption of these metals in upstream systems. Substantial release of trace metals from the sediment was observed even by a modest decrease of pH from 6.4 to 5.9. Therefore, the metal-rich sediment of the lake should be considered as potentially hazardous to bottom-dwelling aquatic species and other organisms in the local food chain. In addition, if the reservoir is dredged or if the dam is removed, the accumulated sediment may have to be treated for recovery of sorbed metals.     

CONTROL OF LAKE PHOSPHORUS WITH ALUMINUM SULFATE: DOSE DETERMINATION AND APPLICATION TECHNIQUES1

ABSTRACT: Nutrient diversion does not always bring about prompt and sufficient reduction in lake phosphorus concentration due to recycling from nutrient rich sediments. Certain lakes and reservoirs may continue to experience nuisance algal blooms and require additional restorative steps. The phosphorus precipitation/inactivation technique is a procedure to remove phosphorus from the water column and to control its release from sediments in order to achieve P-limiting conditions to algal growth. Aluminum salts have been used in advanced waste water treatment to remove phosphorus and this technology was extended to lake rehabilitation. Guidelines for dose calculation and application are generally lacking, and are provided in this report. The dose determination suggested here allows maximum application of aluminum to bottom sediments and thus emphasizes long term control of phosphorus recycling. Dose can be calculated directly from the alkalinity of the water to be treated. Titration of lake water samples of Varying alkalinity allows the establishment of the relationship between residual dissolved aluminum, alkalinity, and dose which can then be employed for lake scale applications of alum to lakes and reservoirs. Application equipment and procedures are described. These depend on site characteristics and treatment objectives and include lakeside stores, a distribution pipe, and an application barge and manifold. Alum may also be used to meet other restoration objectives including the treatment of problem flows and the reduction of particulate concentrations.     

A Tool for Modeling the Winter Oxygen Depletion Rate in Arctic Lakes1

Abstract: Many arctic lakes freeze completely in winter. The few that retain unfrozen water for the entire winter period serve as overwintering fish habitat. In addition to serving as fish habitat, water in arctic lakes is needed for industrial and domestic use. Permits for water extraction seek to maximize water use without impacting dissolved oxygen (DO) levels and endangering fish habitat. The relationship between lake volume, winter DO budget, and extraction of water through pumping has historically not been well understood. A management model that could estimate end‐of‐winter DO would improve our understanding of the potential impacts of different management strategies. Using under‐ice DO measurements (November to April) taken from two natural lakes and one flooded gravel mine on the North Slope of Alaska, a physically based model was developed to predict end‐of‐winter DO concentration, water‐column DO profiles, and winter oxygen depletion rate in arctic lakes during periods of ice cover. Comparisons between the measured and model‐predicted oxygen profiles in the three study lakes suggest that the depth‐based DO modeling tool presented herein can be used to adequately predict the amount of DO available in arctic lakes throughout winter.     

THE EFFECT OF SALT ON SMALL,ARTIFICIAL LAKES1

ABSTRACT: Northridge Lakes, in Milwaukee, Wisconsin, receive runoff from a 3.8 square kilometer drainage area. Almost 30% of the watershed is covered by shopping centers, apartment buildings, and roadways. Deicing agents used on the paved areas, primarily NaCl with some CaCl₂, dissolved in surface runoff and entered the lakes during the winter season. This highly saline inflow was denser than the receiving lake water and formed a saline-water stratum at the lakes' bottom. The salinity stratification remained stable until the spring thaw when a rapid decay began. After the stratification had disappeared, the lakes continued to act as a storage site for dissolved salts. Chloride concentrations in the lakes remained well above the levels found in natural lakes until the advent of the next salting season. Furthermore, outflow from the lakes also showed abnormally high salt concentrations year-round.     

Limnological effects of wood ash application to the subcatchments of boreal,humic lakes

To assess environmental risks of wood ash, limnological effects of ash application to the drainage basins of two small, humic lakes and one reference lake in southern Finland were examined in this three-year study. Treated areas corresponded to 12 and 19% of the total catchment and the amount of wood ash added was 6400 kg ha(-1). Immediate effects of wood ash on lake water were investigated in three tank experiments each lasting 1.5 wk. In tank experiments, addition of wood ash increased pH, alkalinity, conductivity, and Ca and P concentrations of humic lake water, while growth of phytoplankton decreased. After wood ash application to the subcatchments, pH, alkalinity, conductivity, and concentrations of K+, SO4(2-), and Cl- slightly increased, both in inflowing waters and in the lakes, but no increased leaching of Ca, N, or P from the treated subcatchments occurred. Phytoplankton biomass increased in both experimental lakes in comparison with the reference lake. In the lake with 19% application rate to the catchment, zooplankton biomass also increased. The results indicate that, over the short term, a small-scale ash treatment to a forested drainage basin will not necessarily cause significant changes in the water quality of boreal humic lakes, but at higher application rates, changes in water chemistry and biology are more evident.     

Improvement of soil quality after "alperujo" compost application to two contaminated soils characterised by differing heavy metal solubility

Reclamation of trace element polluted soils often requires the improvement of the soil quality by using appropriate organic amendments. Low quality compost from municipal solid waste has been tested for reclamation of soils, but these materials can provide high amounts of heavy metals. Therefore, a high-quality compost, with low levels of heavy metals, produced from the main by-product of the Spanish olive oil extraction industry ("alperujo") was evaluated for remediation of soils affected by a pyritic mine sludge. Two contaminated soils were selected from the same area: they were characterised by differing pH values (4.6 and 7.3) and total metal concentrations, which greatly affected the fractionation of the metals. Compost was applied to soil at two rates (equivalent to 48 and 72 Tm ha(-1)) and compared with an inorganic fertiliser treatment. Compost acted as an available nutrient source (C, N and P) and showed a low mineralisation rate, suggesting a slow release of nutrients and thus favouring long term soil fertility. In addition, the liming effect of the compost led to a significant reduction of toxicity for soil microorganisms in the acidic soil and immobilisation of soil heavy metals (especially Mn and Zn), resulting in a clear increase in both soil microbial biomass and nitrification. Such positive effects were clearly greater than those provoked by the mineral fertiliser even at the lowest compost application rate, which indicates that this type of compost can be very useful for bioremediation programmes (reclamation and revegetation of polluted soils) based on phytostabilisation strategies.     

Lake Temperature and Ice Cover Regimes in the Alaskan Subarctic and Arctic: Integrated Monitoring,Remote Sensing,and Modeling1

Arp, C.D., B.M. Jones, M. Whitman, A. Larsen, and F.E. Urban, 2010. Lake Temperature and Ice Cover Regimes in the Alaskan Subarctic and Arctic: Integrated Monitoring, Remote Sensing, and Modeling. Journal of the American Water Resources Association (JAWRA) 46(4): 777-791. DOI: 10.1111/j.1752-1688.2010.00451.x Abstract: Lake surface regimes are fundamental attributes of lake ecosystems and their interaction with the land and atmosphere. High latitudes may be particularly sensitive to climate change, however, adequate baselines for these lakes are often lacking. In this study, we couple monitoring, remote sensing, and modeling techniques to generate baseline datasets of lake surface temperature and ice cover in the Alaskan Subarctic and Arctic. No detectable trends were observed during this study period, but a number of interesting patterns were noted among lakes and between regions. The largest Arctic lake was relatively unresponsive to air temperature, while the largest Subarctic lake was very responsive likely because it is fed by glacial runoff. Mean late summer water temperatures were higher than air temperatures with differences ranging from 1.7 to 5.4°C in Subarctic lakes and from 2.4 to 3.2°C in Arctic lakes. The warmest mean summer water temperature in both regions was in 2004, with the exception of Subarctic glacially fed lake that was highest in 2005. Ice-out timing had high coherence within regions and years, typically occurring in late May in Subarctic and in early-July in Arctic lakes. Ice-on timing was more dependent on lake size and depth, often varying among lakes within a region. Such analyses provide an important baseline of lake surface regimes at a time when there is increasing interest in high-latitude water ecosystems and resources during an uncertain climate future.     

PHOSPHORUS MANAGEMENT TO PROTECT LAKE WATER QUALITY1

ABSTRACT: The Hallett Quarry gravel pit lakes are an active sand and gravel extraction operation located 0.4 km north of the City of Ames, Iowa. During periods of drought, these lakes serve as a supplemental water supply for Ames. A modified version of the Vollenweider input-output model was used to predict future water quality under various watershed land use, drainage, and lake configurations. The dominant factor controlling the future water quality of the lakes was found to be the nutrient input. It is recommended that a management plan to protect the future water quality should be oriented towards reducing the sources of phosphorus to the lakes.     

THE DEVELOPMENT OF A COMBINED WATER QUALITY INDEX1

ABSTRACT: Use-oriented benefits and treatment costs analysis has been incorporated into a water quality index to show an economically optimized concentration for the treatment of the pollutants and the resulting water quality. This combined water quality index can be used in decisionmaking at the federal and local government levels. Five major pollutants, i.e., coliforms, nitrogen, phosphorus, suspended solids, and detergent, have been considered for the municipal waste water. With each higher level of improvement the treatment costs increase accordingly and the benefits associated with the reuse of this treated waste water will increase too but not for the nutrient removal in agricultural use. The optimal concentration is determined when the marginal costs equal the marginal benefits. The combined water quality index is the combination of the maximum net benefits and the water quality index of the optimized residual concentrations. This water quality index is zero dollars for the Tucson region in this study. The possible reclaimed use of municipal waste water is for agricultural irrigation and recreational lakes for the Tucson region.     

Decreased carbon and nutrient input to boreal lakes from particulate organic matter following riparian clear-cutting

The plankton communities of oligotrophic Canadian Shield lakes are strongly regulated by the allochthonous supply of total phosphorus (TP) and dissolved organic carbon (DOC), a proportion of both of which originate from particulate organic matter. Although decreased inputs of allochthonous leaf litter have been documented for small streams whose riparian forests have been removed, no such data exist for boreal lakes. Through estimates of airborne litter input from forested and clear-cut shorelines and laboratory measurements of concentrations released from leaf leachate, we determined that riparian deforestation resulted in reductions of DOC from 17.8 to 0.4 g/m shoreline/yr and of TP from 2.9 to 0.3 g/m shoreline/yr. Previous predictive models indicate that such reductions may be substantial enough to decrease basic metabolic processes of lake plankton communities by as much as 9% in primary production and 17% in respiration.