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Sample records for inorganic stream water

  1. STREAM WATER QUALITY MODEL

    EPA Science Inventory

    QUAL2K (or Q2K) is a river and stream water quality model that is intended to represent a modernized version of the QUAL2E (or Q2E) model (Brown and Barnwell 1987). Q2K is similar to Q2E in the following respects:

    • One dimensional. The channel is well-mixed vertically a...

    • Elevated stream inorganic nitrogen impacts on a dominant riparian tree species: Results from an experimental riparian stream system

      NASA Astrophysics Data System (ADS)

      Hultine, K. R.; Jackson, T. L.; Burtch, K. G.; Schaeffer, S. M.; Ehleringer, J. R.

      2008-12-01

      The release of inorganic nitrogen from intensive agricultural practices and urbanization has resulted in significant alterations of the aquatic nitrogen cycle in riparian ecosystems. Nevertheless, impacts of stream nitrogen inputs on the terrestrial nitrogen cycle and the water and carbon cycles are unclear. Information on terrestrial ecosystem responses to stream N loading is largely absent in part because of the difficulty in controlling for temporal and spatial variation in streamflow, geomorphology, climate, and vegetation. To address these issues, we constructed a dual-plot artificial stream riparian system within a 10-year-old plantation of a dominant riparian tree species, box elder (Acer negundo). The dual-plot design allowed for different concentrations of stream inorganic nitrogen between plots while controlling for ecohydrologic and geohydrologic variability. The system was used to investigate elevated inorganic stream nitrogen impacts on water use patterns, above-ground productivity, and leaf chemistry of streamside box elder trees over two consecutive growing seasons (2006 and 2007). One plot received inorganic soluble fertilizer that brought the NO3 concentration of stream water from 5 μmol l-1 to about 100 μmol l-1, while the second plot received no additional nitrogen. Relative stem sap flux density (Js) did not vary between plots until near the conclusion of the 2006 growing season, when trees in the fertilized plot showed a steep upswing in Js relative to trees in the control plot. Sap flux in 2007 increased consistently by 0.4% day-1 in the fertilized plot relative to the control plot over a 75-day period, before leveling off near the conclusion of the growing season. At the onset of the experiment, leaf nitrogen per unit mass and leaf nitrogen per unit area were significantly higher in the control plot, and leaf C:N ratios were lower. In 2007, however, differences in leaf chemistry disappeared, suggesting that leaf nitrogen increased in the

    • Solute-specific scaling of inorganic nitrogen and phosphorus uptake in streams

      NASA Astrophysics Data System (ADS)

      Hall, R. O., Jr.; Baker, M. A.; Rosi-Marshall, E. J.; Tank, J. L.; Newbold, J. D.

      2013-11-01

      Stream ecosystem processes such as nutrient cycling may vary with stream position in the network. Using a scaling approach, we examined the relationship between stream size and nutrient uptake length, which represents the mean distance that a dissolved solute travels prior to removal from the water column. Ammonium (NH4+) uptake length increased proportionally with stream size measured as specific discharge (discharge/stream width) with a scaling exponent = 1.01. In contrast, uptake lengths for nitrate (NO3-) and soluble reactive phosphorus (SRP) increased more rapidly than increases in specific discharge (scaling exponents = 1.19 for NO3- and 1.35 for SRP). Additionally, the ratio of inorganic nitrogen (N) uptake length to SRP uptake length declined with stream size; there was relatively lower demand for SRP compared to N as stream size increased. Finally, we related the scaling of uptake length with specific discharge to that of stream length using Hack's law and downstream hydraulic geometry. Ammonium uptake length increased less than proportionally with distance from the headwaters, suggesting a strong role for larger streams and rivers in regulating nutrient transport.

    • REMOVING DISSOLVED INORGANIC CONTAMINANTS FROM WATER

      EPA Science Inventory

      Dissolved inorganic contaminants in water can be cationic, anionic, or neutral forms of ions, atoms, or molecules of any element in the periodic table. The article describes the physicochemical treatment processes typically used to remove the more common inorganic contaminants fr...

    • Long-term declines in stream and river inorganic nitrogen (N) export correspond to forest change.

      PubMed

      Lucas, Richard W; Sponseller, Ryan A; Gundale, Michael J; Stendahl, Johan; Fridman, Jonas; Högberg, Peter; Laudon, Hjalmar

      2016-03-01

      Human activities have exerted a powerful influence on the biogeochemical cycles of nitrogen (N) and carbon (C) and drive changes that can be a challenge to predict given the influence of multiple environmental stressors. This study focused on understanding how land management and climate change have together influenced terrestrial N storage and watershed inorganic N export across boreal and sub-arctic landscapes in northern Sweden. Using long-term discharge and nutrient concentration data that have been collected continuously for over three decades, we calculated the hydrologic inorganic N export from nine watersheds in this region. We found a consistent decline in inorganic N export from 1985 to 2011 over the entire region from both small and large watersheds, despite the absence of any long-term trend in river discharge during this period. The steepest declines in inorganic N export were observed during the growing season, consistent with the hypothesis that observed changes are biologically mediated and are not the result of changes in long-term hydrology. Concurrent with the decrease in inorganic N export, we report sustained increases in terrestrial N accumulation in forest biomass and soils across northern Sweden. Given the close communication of nutrient and energy stores between plants, soils, and waters, our results indicate a regional tightening of the N cycle in an already N-limited environment as a result of changes in forest management and climate-mediated growth increases. Our results are consistent with declining inorganic N efflux previously reported from small headwater streams in other ecosystems and shed new light on the mechanisms controlling these patterns by identifying corresponding shifts in the terrestrial N balance, which have been altered by a combination of management activities and climate change. PMID:27209794

    • Lagrangian mass-flow investigations of inorganic contaminants in wastewater-impacted streams

      USGS Publications Warehouse

      Barber, L.B.; Antweiler, R.C.; Flynn, J.L.; Keefe, S.H.; Kolpin, D.W.; Roth, D.A.; Schnoebelen, D.J.; Taylor, H.E.; Verplanck, P.L.

      2011-01-01

      Understanding the potential effects of increased reliance on wastewater treatment plant (WWTP) effluents to meet municipal, agricultural, and environmental flow requires an understanding of the complex chemical loading characteristics of the WWTPs and the assimilative capacity of receiving waters. Stream ecosystem effects are linked to proportions of WWTP effluent under low-flow conditions as well as the nature of the effluent chemical mixtures. This study quantifies the loading of 58 inorganic constituents (nutrients to rare earth elements) from WWTP discharges relative to upstream landscape-based sources. Stream assimilation capacity was evaluated by Lagrangian sampling, using flow velocities determined from tracer experiments to track the same parcel of water as it moved downstream. Boulder Creek, Colorado and Fourmile Creek, Iowa, representing two different geologic and hydrologic landscapes, were sampled under low-flow conditions in the summer and spring. One-half of the constituents had greater loads from the WWTP effluents than the upstream drainages, and once introduced into the streams, dilution was the predominant assimilation mechanism. Only ammonium and bismuth had significant decreases in mass load downstream from the WWTPs during all samplings. The link between hydrology and water chemistry inherent in Lagrangian sampling allows quantitative assessment of chemical fate across different landscapes. ?? 2011 American Chemical Society.

    • Removing dissolved inorganic contaminants from water

      SciTech Connect

      Clifford, D.; Subramonian, S.; Sorg, T.J.

      1986-11-01

      This article describes the physicochemical treatment processes typically used to remove the more common inorganic contaminants from water and wastewater. These are precipitation, coprecipitation, adsorption, ion exchange, membrane separations by reverse osmosis and electrodialysis, and combinations of these processes. The general criteria for process selection are discussed, and the processes and their typical applications are described.

    • Stream Water and Sediment Phosphorus Equilibrium Concentrations in Ozark Streams

      Technology Transfer Automated Retrieval System (TEKTRAN)

      Little information is broadly available on the fate and transport of dissolved phosphorus (DP) in streams draining agricultural and urban catchments, although in-stream processes might have a substantial influence on downstream transport. This study evaluated sediment-water P equilibrium concentrat...

    • Role of microbes associated with organic and inorganic substrates in phosphorus spiralling in a woodland stream

      SciTech Connect

      Elwood, J.W.; Newbold, J.D.; O'Neill, R.V.; Stark, R.W.; Singley, P.T.

      1980-01-01

      Laboratory and field experiments were conducted to determine if nutrient spiralling is primarily a biological process. The experiments were conducted to examine the role of microbial uptake and abiotic sorption onto organic and inorganic substrates in the uptake of PO/sub 4/-P in Walker Branch, a small, first-order woodland stream in east Tennessee, to estimate the total, microbial, and adsorptive pool sizes of exchangeable phosphorus associated with five particulate organic matter from this stream, and to measure the turnover rate of PO/sub 4/-P by live and sterile inorganic substrates in Walker Branch.

    • Water Stream "Loop-the-Loop"

      ERIC Educational Resources Information Center

      Jefimenko, Oleg

      1974-01-01

      Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

    • Solute specific scaling of inorganic nitrogen and phosphorus uptake in streams

      NASA Astrophysics Data System (ADS)

      Hall, R. O., Jr.; Baker, M. A.; Rosi-Marshall, E. J.; Tank, J. L.

      2013-04-01

      Stream ecosystem processes such as nutrient cycling may vary with stream position in the watershed. Using a scaling approach, we examined the relationship between stream size and nutrient uptake length, which represents the mean distance that a dissolved solute travels prior to removal from the water column. Ammonium uptake length increased proportionally with stream size measured as specific discharge (discharge/stream width) with a scaling exponent = 1.01. In contrast, the scaling exponent for nitrate (NO3-) was 1.19 and for soluble reactive phosphorus (SRP) was 1.35, suggesting that uptake lengths for these nutrients increased more rapidly than increases in specific discharge. Additionally, the ratio of nitrogen (N) uptake length to SRP uptake length declined with stream size; there was lower demand for SRP relative to N as stream size increased. Ammonium and NO3- uptake velocity positively related with stream metabolism, while SRP did not. Finally, we related the scaling of uptake length and specific discharge to that of stream length using Hack's law and downstream hydraulic geometry. Ammonium uptake length increased less than proportionally with distance from the headwaters, suggesting a strong role for larger streams and rivers in regulating nutrient transport.

    • Carbon isotope fractionation of dissolved inorganic carbon (DIC) due to outgassing of carbon dioxide from a headwater stream

      USGS Publications Warehouse

      Doctor, D.H.; Kendall, C.; Sebestyen, S.D.; Shanley, J.B.; Ohte, N.; Boyer, E.W.

      2008-01-01

      The stable isotopic composition of dissolved inorganic carbon (??13C-DIC) was investigated as a potential tracer of streamflow generation processes at the Sleepers River Research Watershed, Vermont, USA. Downstream sampling showed ?? 13C-DIC increased between 3-5??? from the stream source to the outlet weir approximately 0??5 km downstream, concomitant with increasing pH and decreasing PCO2. An increase in ??13C-DIC of 2.4 ?? 0??1??? per log unit decrease of excess PCO2 (stream PCO2 normalized to atmospheric PCO2) was observed from downstream transect data collected during snowmelt. Isotopic fractionation of DIC due to CO2 outgassing rather than exchange with atmospheric CO2 may be the primary cause of increased ?? 13C-DIC values downstream when PCO2 of surface freshwater exceeds twice the atmospheric CO2 concentration. Although CO2 outgassing caused a general increase in stream ??13C-DIC values, points of localized groundwater seepage into the stream were identified by decreases in ??13C-DIC and increases in DIC concentration of the stream water superimposed upon the general downstream trend. In addition, comparison between snowmelt, early spring and summer seasons showed that DIC is flushed from shallow groundwater flowpaths during snowmelt and is replaced by a greater proportion of DIC derived from soil CO2 during the early spring growing season. Thus, in spite of effects from CO2 outgassing, ??13C of DIC can be a useful indicator of groundwater additions to headwater streams and a tracer of carbon dynamics in catchments. Copyright ?? 2007 John Wiley & Sons, Ltd.

    • Methylation of inorganic mercury in polar marine waters

      NASA Astrophysics Data System (ADS)

      Lehnherr, Igor; St. Louis, Vincent L.; Hintelmann, Holger; Kirk, Jane L.

      2011-05-01

      Monomethylmercury is a neurotoxin that accumulates in marine organisms, with serious implications for human health. The toxin is of particular concern to northern Inuit peoples, for example, whose traditional diets are composed primarily of marine mammals and fish. The ultimate source of monomethylmercury to marine organisms has remained uncertain, although various potential sources have been proposed, including export from coastal and deep-sea sediments and major river systems, atmospheric deposition and water-column production. Here, we report results from incubation experiments in which we added isotopically labelled inorganic mercury and monomethylmercury to seawater samples collected from a range of sites in the Canadian Arctic Archipelago. Monomethylmercury formed from the methylation of inorganic mercury in all samples. Demethylation of monomethylmercury was also observed in water from all sites. We determined steady-state concentrations of monomethylmercury in marine waters by incorporating the rate constants for monomethylmercury formation and degradation derived from these experiments into a numerical model. We estimate that the conversion of inorganic mercury to monomethylmercury in the water column accounts for around 47% (+/-62%, standard deviation) of the monomethylmercury present in polar marine waters, with site-to-site differences in inorganic mercury and monomethylmercury levels accounting for most of the variability. We suggest that water-column methylation of inorganic mercury is a significant source of monomethylmercury in pelagic marine food webs in the Arctic, and possibly in the world's oceans in general.

    • Stream-Groundwater Interaction Buffers Seasonal Changes in Urban Stream Water Quality

      NASA Astrophysics Data System (ADS)

      Ledford, S. H.; Lautz, L. K.

      2013-12-01

      Urban streams in the northeastern United States have large road salt inputs during winter, increased nonpoint sources of inorganic nitrogen, and decreased short-term and permanent storage of nutrients. Meadowbrook Creek, a first order stream in Syracuse, New York, flows along a negative urbanization gradient, from a channelized and armored stream running through the middle of a roadway to a pool-riffle stream meandering through a broad, vegetated floodplain with a riparian aquifer. In this study we investigated how reconnection to groundwater and introduction of riparian vegetation impacted surface water chemistry by making bi-weekly longitudinal surveys of stream water chemistry in the creek from May 2012 until June 2013. Chloride concentrations in the upstream, urban reach of Meadowbrook Creek were strongly influenced by discharge of road salt to the creek during snow melt events in winter and by the chemistry of water draining an upstream retention basin in summer. Chloride concentrations ranged from 161.2 mg/L in August to 2172 mg/L in February. Chloride concentrations in the downstream, 'connected' reach had less temporal variation, ranging from 252.0 mg/L in August to 1049 mg/L in January, and were buffered by groundwater discharge, as the groundwater chloride concentrations during the sampling period ranged from 84.0 to 655.4 mg/L. Groundwater discharge resulted in higher chloride concentrations in summer and lower concentrations in winter in the connected reach relative to the urban reach, minimizing annual variation. In summer, there was little-to-no nitrate in the urban reach due to a combination of limited sources and high primary productivity. In contrast, during the summer, nitrate concentrations reached over 1 mg N/L in the connected reach due to the presence of riparian vegetation and lower nitrate uptake due to cooler temperatures and shading. During the winter, when temperatures fell below freezing, nitrate concentrations in the urban reach

    • INORGANIC CHEMICAL CHARACTERIZATION OF WATER TREATMENT PLANT RESIDUALS

      EPA Science Inventory

      The study obtained field data on the inorganic contaminants and constituents in residuals produced by Water Treatment Plants (WTPs). Eight WTPs were studied based on treatment technology, contamination or suspected contamination of raw water, and efficiency in the removal of cont...

    • Stream network expansion: a riparian water quality factor

      NASA Astrophysics Data System (ADS)

      Wigington, P. J., Jr.; Moser, T. J.; Lindeman, D. R.

      2005-05-01

      Little is known about how active stream network expansion during rainstorms influences the ability of riparian buffers to improve water quality. We used aerial photographs to quantify stream network expansion during the wet winter season in five agricultural catchments in western Oregon, USA. Winter stream drainage densities were nearly two orders of magnitude greater than summer stream densities, and agricultural land use was much more abundant along transient portions (e.g. swales, road ditches) of stream networks. Water moving from agricultural fields into expanded stream networks during large hydrologic events has the opportunity to bypass downstream riparian buffers along perennial streams and contribute nonpoint-source pollutants directly into perennial stream channels.

    • Mild desalination of various raw water streams.

      PubMed

      Groot, C K; van den Broek, W B P; Loewenberg, J; Koeman-Stein, N; Heidekamp, M; de Schepper, W

      2015-01-01

      For chemical industries, fresh water availability is a pre-requisite for sustainable operation. However, in many delta areas around the world, fresh water is scarce. Therefore, the E4 Water project (www.e4water.eu) comprises a case study at the Dow site in Terneuzen, The Netherlands, which is designed to develop commercial applications for mild desalination of brackish raw water streams from various origins to enable reuse in industry or agriculture. This study describes an effective two-stage work process, which was used to narrow down a broad spectrum of desalination technologies to a selection of the most promising techniques for a demonstration pilot at 2-4 m³/hour. Through literature study, laboratory experiments and multi-criteria analysis, nanofiltration and electrodialysis reversal were selected, both having the potential to attain the objectives of E4Water at full scale. PMID:26204068

    • Spatial variability in dissolved organic matter and inorganic nitrogen concentrations in a semiarid stream, San Pedro River, Arizona

      NASA Astrophysics Data System (ADS)

      Brooks, Paul D.; Lemon, Michelle M.

      2007-09-01

      We performed synoptic sampling of a 95-km reach of the San Pedro River, Arizona, to identify the effects of regional hydrology and land use on dissolved carbon and nitrogen concentrations. Six synoptic surveys, two before, two during, and two after the 2002 monsoon season, encompassed periods of both low and high stream discharge. Chloride concentrations and δ18O values during low-flow periods indicated the river was divided into three hydrologically distinct reaches each roughly 30 km long. Upper and lower reaches were characterized by areas of localized groundwater input followed by downstream evapo-concentration gradients, limited downstream solute transport, and highly variable carbon and nitrogen concentrations. In contrast, the middle reach was characterized by widespread groundwater input, continuous downstream hydrologic connectivity, and less variable carbon and nitrogen concentrations. During the monsoon season, base flow discharge increased five- to ten-fold, dissolved organic matter and inorganic N increased two- to ten-fold, Fluorescence Index (FI) values indicated a large input of terrestrial solutes, and both chloride concentrations and δ18O values indicated that stream water and alluvial groundwater were well mixed along the entire 95 km reach. Concurrently, the middle reach that exhibited continuous hydrologic connectivity during the nonmonsoon season was a net sink for N, while the reaches characterized by limited hydrologic connectivity during the low-flow season exhibited net N export. Our data suggest that instream biogeochemical cycling during the monsoon season is influenced by antecedent conditions, specifically hydrologic connectivity, during the dry season.

    • [Characteristics and Transport Patterns of Ammonia, Nitrites, Nitrates and Inorganic Nitrogen Flux at Epikarst Springs and a Subterranean Stream in Nanshan, Chongqing].

      PubMed

      Zhang, Yuan-zhu; He, Qiu-fang; Jiang, Yong-jun; Li, Yong

      2016-04-15

      In a karst groundwater system, it develops complex multiple flows because of its special geological structure and unique physical patterns of aquifers. In order to investigate the characteristics and transport patterns of ammonia, nitrite and nitrate in epikarst water and subterranean stream, the water samples were collected monthly in a fast-urbanizing karst region. The results showed distinctive characteristics of three forms of inorganic nitrogen. The concentration of inorganic nitrogen was stable in the epikarst water while it was fluctuant in the subterranean stream. Epikarst water was less affected by rainfall and sewage compared with subterranean stream. In epikarst water, the nitrate concentration was much higher than the ammonia concentration. Dissolved inorganic nitrogen, mainly from non-point source pollution related to agricultural activities, passed in and out of the epikarst water based on a series of physical; chemical and biological processes in the epikarst zone, such as ammonification, adsorption and nitrification. On the contrary, subterranean stream showed a result of NH₄⁺-N > NO₃⁻-N in dry seasons and NO₃⁻-N > NH₄⁺-N in rainy seasons. This can be due to the fact that sanitary and industrial sewage flowed into subterranean river through sinkholes, fissures and grikes in dry season. Dissolved inorganic nitrogen in subterranean river was mainly from the non-point source pollution in wet season. Non-point source pollutants entered into subterranean water by two transport ways, one by penetration along with vadose flow through fissures and grikes, and the other by conduit flow through sinkholes from the surface runoff, soil water flow and epikarst flow. The export flux of DIN was 56.05 kg · (hm² · a)⁻¹, and NH₄⁺-N and NO₃⁻-N accounted for 46.03% and 52.51%, respectively. The contributions of point-source pollution and non point-source pollution to the export flux of DIN were 25.08% and 74.92%, respectively, based on run

    • Lateral inflows, stream-groundwater exchange, and network geometry influence stream water composition

      NASA Astrophysics Data System (ADS)

      Mallard, John; McGlynn, Brian; Covino, Tim

      2014-06-01

      The role of stream networks and their hydrologic interaction with hillslopes and shallow groundwater in modifying and transporting watershed signals is an area of active research. One of the primary ways that stream networks can modify watershed signals is through spatially variable stream gains and losses, described herein as hydrologic turnover. We measured hydrologic gain and loss at the reach scale using tracer experiments throughout the Bull Trout watershed in the Sawtooth Mountains of Idaho. We extended the results of reach scale experiments to the stream network using empirical relationships between (1) watershed area and stream discharge and (2) stream discharge and percent stream water loss to the groundwater system. We thus incorporate linkages between (1) hillslopes and stream networks via lateral inflows and (2) stream networks and shallow groundwater via hydrologic exchange. We implemented these relationships within a concise analytical framework to simulate hydrologic turnover across stream networks and estimate the variable influence exerted by upstream reaches and streamflow source locations on stream water composition across stream networks. Application to six natural Sawtooth watersheds and seven synthetic watersheds with varying topographic structure and stream network geometry indicated that contributions to discharge from any upstream source depend on the magnitude of the initial input, but also on the distribution of hydrologic turnover occurring along the stream network. The evolution of stream water source compositions along stream networks was unique in each watershed due to the combination of watershed structure and stream network geometry. Our results suggest that a distributed representation of hydrologic turnover at the stream network scale can improve understanding of how the stream network can modify source water compositions along the stream.

  1. Should the Clean Water Act Follow Stream Water Underground? Managing Beyond the Stream Banks

    NASA Astrophysics Data System (ADS)

    Taptich, M. N.; Gooseff, M. N.

    2010-12-01

    The Clean Water Act was designed to protect the integrity of surface waters of the United States. Originally limited to solely waters that were traditionally navigable, the jurisdictional bounds of the Clean Water Act have been expanded to include many other ‘waters of the United States,’ some of which are in fact unnavigable. This expansion of the definition of ‘navigable waters’ has brought many litigative challenges to the true jurisdictional limits of the Act. The recent Supreme Court opinions in Rapanos v. United States (2006) and the subsequent interpretation by lower federal courts have set the precedent for a new approach to jurisdictional determinations, where considerations of function and effect act as gatekeepers for inclusion under the CWA. Justice Kennedy’s significant nexus standard from Rapanos (2006) limits jurisdictional coverage under the Clean Water Act to ‘waters that have a significant nexus with traditional navigable waters.’ Thus, establishing a ‘significant nexus’ between a water body in question and traditionally navigable waters satisfies the requisites needed for inclusion within the scope of the Clean Water Act. By and large there has been a lack of consideration for the near subsurface components of streams when discussing the application of the significant nexus standard. We propose that hyporheic zones, a volume of alluvial aquifer that hosts the exchange of stream water, should be covered under the Clean Water Act, since these zones are intimately connected with their adjoining surface waters and facilitate many processes that are key to supporting healthy stream ecosystems and good water quality. Given the opinions rendered in Rapanos (2006) and the guidance offered by the EPA and Corps following the decision, we demonstrate that the hyporheic zone fulfills each of the functional and ecological example factors used to establish a significant nexus. The implications of this argument include the conversion of our

  2. Salmon carcasses increase stream productivity more than inorganic fertilizer pellets: A test on multiple trophic levels in streamside experimental channels

    USGS Publications Warehouse

    Wipfli, Mark S.; Hudson, John P.; Caouette, John P.; Mitchell, N.L.; Lessard, Joanna L.; Heintz, Ron A.; Chaloner, D.T.

    2010-01-01

    Inorganic nutrient amendments to streams are viewed as possible restoration strategies for re-establishing nutrients and stream productivity throughout the western coast of North America, where salmon runs and associated marine-derived nutrient subsidies have declined. In a mesocosm experiment, we examined the short-term (6 weeks) comparative effects of artificial nutrient pellets and salmon carcasses, alone (low and high amounts) and in combination, on stream food webs. Response variables included dissolved nutrient concentrations, biofilm ash-free dry mass (AFDM) and chlorophyll-alevels, macroinvertebrate density, growth and body condition of juvenile coho salmon Oncorhynchus kisutch, and whole-body lipid content of invertebrates and juvenile coho salmon. Most of the response variables were significantly influenced by carcass treatment; the only response variable significantly influenced by fertilizer pellet treatment was soluble reactive phosphorus (SRP) concentration. Ammonium-nitrogen concentration was the only response variable affected by both (low and high) levels of carcass treatment; all others showed no significant response to the two carcass treatment levels. Significant treatment × time interactions were observed for all responses except nitrate; for most responses, significant treatment effects were detected at certain time periods and not others. For example, significantly higher SRP concentrations were recorded earlier in the experiment, whereas significant fish responses were observed later. These results provide evidence that inorganic nutrient additions do not have the same ecological effects in streams as do salmon carcasses, potentially because inorganic nutrient additions lack carbon-based biochemicals and macromolecules that are sequestered directly or indirectly by consumers. Salmon carcasses, preferably deposited naturally during spawning migrations, appear to be far superior to inorganic nutrient amendments for sustaining and restoring

  3. A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate.

    PubMed

    Ekpo, U; Ross, A B; Camargo-Valero, M A; Williams, P T

    2016-01-01

    Thermal hydrolysis and hydrothermal processing show promise for converting biomass into higher energy density fuels. Both approaches facilitate the extraction of inorganics into the aqueous product. This study compares the behaviour of microalgae, digestate, swine and chicken manure by thermal hydrolysis and hydrothermal processing at increasing process severity. Thermal hydrolysis was performed at 170°C, hydrothermal carbonisation (HTC) was performed at 250°C, hydrothermal liquefaction (HTL) was performed at 350°C and supercritical water gasification (SCWG) was performed at 500°C. The level of nitrogen, phosphorus and potassium in the product streams was measured for each feedstock. Nitrogen is present in the aqueous phase as organic-N and NH3-N. The proportion of organic-N is higher at lower temperatures. Extraction of phosphorus is linked to the presence of inorganics such as Ca, Mg and Fe in the feedstock. Microalgae and chicken manure release phosphorus more easily than other feedstocks. PMID:26615335

  4. Key stream/sediment exchanges of water and heat near stream mouths

    NASA Astrophysics Data System (ADS)

    Constantz, J. E.; Naranjo, R. C.; Niswonger, R. G.; Neilson, B. T.; Allander, K.; Zamora, C.; Smith, D. W.; Stonestrom, D. A.

    2014-12-01

    The section of stream discharging to a lake or other surface-water body is referred to as the stream mouth, a stream reach with rapidly changing hydrologic conditions, leading to unique aquatic and benthic ecology, as well as a visibly active fishery habitat. Of environmental significance, bridges, control structures, channelization and foot traffic are common near stream mouths, warranting comparisons of natural and channelized stream mouths. The present work completes the first investigation focusing specifically on the hydrology of surface-water/sediment exchanges at stream-mouth reaches discharging to lakes and compares these exchanges to those measured along the nearby shoreline in both a qualitative and quantitative manner. Heat and water exchanges for two common types of stream mouths (a natural stream with a summer barrier bar and a channelized stream mouth) are compared with comparable exchanges along the nearby shoreline on the north shore of Lake Tahoe located in the Central Sierra Nevada Mountain Range (CA/NV, US). The study site was selected partially due the abundance of streams discharging into the lake of both a natural and channelized nature (~30 small streams with a large number of both types of stream mouths). Heat and water exchanges were both qualitatively and quantitatively distinct for the three types of hydrologic settings, with (1) cool, low velocity, longitudinal (hyporheic) flowpaths observed below the channelized stream mouth, discharging beneath the warmer, more buoyant lakeshore water, (2) the nearby shoreline receiving relatively warm, higher velocity discharge and (3) for the natural stream mouth, there was strong diurnal temperature pattern in groundwater discharging through the seasonal barrier beach to the lake. Impacts of strong 2013 wave action on exchanges were also distinct for the three settings, with (1) channelization allowing waves to extend well upstream, (2) a lesser invasive impact in the shoreline swash zone exchanges

  5. Low temperature removal of inorganic sulfur compounds from mining process waters.

    PubMed

    Liljeqvist, Maria; Sundkvist, Jan-Eric; Saleh, Amang; Dopson, Mark

    2011-06-01

    Process water and effluents from mining operations treating sulfide rich ores often contain considerable concentrations of metastable inorganic sulfur compounds such as thiosulfate and tetrathionate. These species may cause environmental problems if released to downstream recipients due to oxidation to sulfuric acid catalyzed by acidophilic microorganisms. Molecular phylogenic analysis of the tailings pond and recipient streams identified psychrotolerant and mesophilic inorganic sulfur compound oxidizing microorganisms. This suggested year round thiosalt oxidation occurs. Mining process waters may also contain inhibiting substances such as thiocyanate from cyanidation plants. However, toxicity experiments suggested their expected concentrations would not inhibit thiosalt oxidation by Acidithiobacillus ferrivorans SS3. A mixed culture from a permanently cold (4-6 °C) low pH environment was tested for thiosalt removal in a reactor design including a biogenerator and a main reactor containing a biofilm carrier. The biogenerator and main reactors were successively reduced in temperature to 5-6 °C when 43.8% of the chemical oxidation demand was removed. However, it was found that the oxidation of thiosulfate was not fully completed to sulfate since low residual concentrations of tetrathionate and trithionate were found in the discharge. This study has demonstrated the potential of using biotechnological solutions to remove inorganic sulfur compounds at 6°C and thus, reduce the impact of mining on the environment. PMID:21280027

  6. In-stream Physical Heterogeneity, Rainfall Aided Flushing, and Discharge on Stream Water Quality.

    PubMed

    Gomes, Pattiyage I A; Wai, Onyx W H

    2015-08-01

    Implications of instream physical heterogeneity, rainfall-aided flushing, and stream discharge on water quality control have been investigated in a headwater stream of a climatic region that has contrasting dry and wet seasons. Dry (low flow) season's physical heterogeneity showed a positive correlation with good water quality. However, in the wet season, physical heterogeneity showed minor or no significance on water quality variations. Furthermore, physical heterogeneity appeared to be more complementary with good water quality subsequent to rainfall events. In many cases stream discharge was a reason for poor water quality. For the dry season, graywater inputs to the stream could be held responsible. In the wet season, it was probably the result of catchment level disturbances (e.g., regulation of ephemeral freshwater paths). Overall, this study revealed the importance of catchment-based approaches on water quality improvement in tandem with in-stream approaches framed on a temporal scale. PMID:26237692

  7. Using water chemistry time series to model dissolved inorganic carbon dynamics in the western Amazon basin

    NASA Astrophysics Data System (ADS)

    Vihermaa, Leena; Waldron, Susan; Newton, Jason

    2013-04-01

    Two small streams (New Colpita and Main Trail) and two rivers (Tambopata and La Torre), in the Tambopata National Reserve, Madre de Dios, Peru, were sampled for water chemistry (conductivity, pH and dissolved oxygen) and hydrology (stage height and flow velocity). In the small streams water chemistry and hydrology variables were logged at 15 minute intervals from Feb 2011 to November 2012. Water samples were collected from all four channels during field campaigns spanning different seasons and targeting the hydrological extremes. All the samples were analysed for dissolved inorganic carbon (DIC) concentration and δ13C (sample size ranging from 77 to 172 depending on the drainage system) and a smaller subset for dissolved organic carbon (DOC) and particulate organic carbon (POC) concentrations. Strong positive relationships were found between conductivity and both DIC concentration and δ13C in the New Colpita stream and the La Torre river. In Tambopata river the trends were less clear and in the Main Trail stream there was very little change in DIC and isotopic composition. The conductivity data was used to model continuous DIC time series for the New Colpita stream. The modelled DIC data agreed well with the measurements; the concordance correlation coefficients between predicted and measured data were 0.91 and 0.87 for mM-DIC and δ13C-DIC, respectively. The predictions of δ13C-DIC were improved when calendar month was included in the model, which indicates seasonal differences in the δ13C-DIC conductivity relationship. At present, continuous DIC sampling still requires expensive instrumentation. Therefore, modelling DIC from a proxy variable which can be monitored continuously with ease and at relatively low cost, such as conductivity, provides a powerful alternative method of DIC determination.

  8. Role of Surface Water-Groundwater Interaction in Regulating Stream Water Chemistry in Urban Streams

    NASA Astrophysics Data System (ADS)

    Ledford, S. H.; Lautz, L. K.; Holdsworth, M.

    2012-12-01

    Urbanization is a major cause of stream degradation in the United States. Surface water -groundwater interaction may naturally mitigate impaired water quality associated with urbanization. Meadowbrook Creek, in Syracuse, New York, flows along a declining urbanization gradient, from headwaters that are highly channelized with armored banks to an outlet that is unconstrained and meanders through a broad, riparian floodplain. Biweekly, longitudinal stream samples were collected every 100 - 600 m in the summer and every 500 - 1000 m in the winter and analyzed for conductivity and major ions. A five well transect in the downstream floodplain was also sampled. A constant rate tracer test was used to quantify groundwater inflow longitudinally during summer baseflow. Specific conductivity decreased along the urban, channelized reach and then increased along the meandering, unconstrained section during the summer, while the opposite occurred during the winter. Nitrate concentrations along the channelized reach were low to below detection (<0.09 - 1.48 mg/L NO3-) in summer; however, nitrate concentrations were consistently higher along the unconstrained reach, ranging from 2.96 - 4.03 mg/L NO3-. The entire stream length had uniformly low nitrate concentrations during winter (0.12-0.57 mg/L NO3-). Sodium and chloride concentrations varied greatly between seasons, with stream concentrations similar to groundwater in the summer (93.28 - 176.45 mg/L Na+ in surface water, 94.81 - 227.05 mg/L Na+ in groundwater; 181.97 - 304.71 mg/L Cl- in surface water, 150.72 - 330.60 mg/L Cl- in groundwater) and an order of magnitude higher in winter, during snowmelt events (450 - 1956 mg/L Na+ and 805.12 - 4517.88 mg/L Cl- in stream water). In winter, sodium and chloride concentrations declined by a maximum of 1189 and 3176.21 mg/L respectively with distance in the unconstrained reach, whereas in summer they increased by 10.01 and 16.12 mg/L respectively with distance. The unconstrained

  9. Impacts by point and diffuse micropollutant sources on the stream water quality at catchment scale

    NASA Astrophysics Data System (ADS)

    Petersen, M. F.; Eriksson, E.; Binning, P. J.; Bjerg, P. L.

    2012-04-01

    The water quality of surface waters is threatened by multiple anthropogenic pollutants and the large variety of pollutants challenges the monitoring and assessment of the water quality. The aim of this study was to characterize and quantify both point and diffuse sources of micropollutants impacting the water quality of a stream at catchment scale. Grindsted stream in western Jutland, Denmark was used as a study site. The stream passes both urban and agricultural areas and is impacted by severe groundwater contamination in Grindsted city. Along a 12 km reach of Grindsted stream, the potential pollution sources were identified including a pharmaceutical factory site with a contaminated old drainage ditch, two waste deposits, a wastewater treatment plant, overflow structures, fish farms, industrial discharges and diffuse agricultural and urban sources. Six water samples were collected along the stream and analyzed for general water quality parameters, inorganic constituents, pesticides, sulfonamides, chlorinated solvents, BTEXs, and paracetamol and ibuprofen. The latter two groups were not detected. The general water quality showed typical conditions for a stream in western Jutland. Minor impacts by releases of organic matter and nutrients were found after the fish farms and the waste water treatment plant. Nickel was found at concentrations 5.8 - 8.8 μg/l. Nine pesticides and metabolites of both agricultural and urban use were detected along the stream; among these were the two most frequently detected and some rarely detected pesticides in Danish water courses. The concentrations were generally consistent with other findings in Danish streams and in the range 0.01 - 0.09 μg/l; except for metribuzin-diketo that showed high concentrations up to 0.74 μg/l. The groundwater contamination at the pharmaceutical factory site, the drainage ditch and the waste deposits is similar in composition containing among others sulfonamides and chlorinated solvents (including vinyl

  10. Streaming Induced by Ultrasonic Vibration in a Water Vessel

    NASA Astrophysics Data System (ADS)

    Nomura, Shinfuku; Murakami, Koichi; Sasaki, Yuuichi

    2000-06-01

    The flow pattern induced by ultrasonic vibration in a water vessel is investigated experimentally using several liquids. In tap water, vortex streaming of cavitation bubbles around the pressure node of a standing wave occurred because of the large number of cavitation bubbles generated by the ultrasonic vibration. Acoustic streaming of the Rayleigh type caused by cavitation bubble streaming is also induced in tap water. In a glycerin aqueous solution of 30%, Eckart streaming, which flowed upward from the vibrator, occurred due to the dissipation of ultrasonic energy caused by viscosity. On the other hand, in degassed water, streaming is hardly generated at all since a uniform and stable standing wave is formed in the water vessel. The velocity of the acoustic streaming generated in the water vessel by 27.8 kHz vibration is 1 to 6 mm/s. The cavitation bubble streaming in tap water is completely independent of normal Rayleigh or Eckart streaming. This bubble streaming is considerably faster than previous streaming.

  11. UTILITY OF ZEOLITES IN REMOVAL OF INORGANIC AND ORGANIC WATER POLLUTANTS

    EPA Science Inventory

    Zeolites are well known for their ion exchange, adsorption and acid catalysis properties. Different inorganic and organic pollutants have been removed from water at room temperature using various zeolites. Synthetic zeolite Faujasite Y has been used to remove inorganic pollutants...

  12. Biological and geochemical controls on diel dissolved inorganic carbon cycling in a low-order agricultural stream: Implications for reach scales and beyond

    USGS Publications Warehouse

    Tobias, C.; Böhlke, J.K.

    2011-01-01

    Movement of dissolved inorganic carbon (DIC) through the hydrologic cycle is an important component of global carbon budgets, but there is considerable uncertainty about the controls of DIC transmission from landscapes to streams, and through river networks to the oceans. In this study, diel measurements of DIC, ??13C-DIC, dissolved oxygen (O2), ??18O-O2, alkalinity, pH, and other parameters were used to assess the relative magnitudes of biological and geochemical controls on DIC cycling and flux in a nutrient-rich, net autotrophic stream. Rates of photosynthesis (P), respiration (R), groundwater discharge, air-water exchange of CO2, and carbonate precipitation/dissolution were quantified through a time-stepping chemical/isotope (12C and 13C, 16O and 18O) mass balance model. Groundwater was the major source of DIC to the stream. Primary production and carbonate precipitation were equally important sinks for DIC removed from the water column. The stream was always super-saturated with respect to carbonate minerals, but carbonate precipitation occurred mainly during the day when P increased pH. We estimated more than half (possibly 90%) of the carbonate precipitated during the day was retained in the reach under steady baseflow conditions. The amount of DIC removed from the overlying water through carbonate precipitation was similar to the amount of DIC generated from R. Air-water exchange of CO2 was always from the stream to the atmosphere, but was the smallest component of the DIC budget. Overall, the in-stream DIC reactions reduced the amount of CO2 evasion and the downstream flux of groundwater-derived DIC by about half relative to a hypothetical scenario with groundwater discharge only. Other streams with similar characteristics are widely distributed in the major river basins of North America. Data from USGS water quality monitoring networks from the 1960s to the 1990s indicated that 40% of 652 stream monitoring stations in the contiguous USA were at or above

  13. Biological and geochemical controls on diel dissolved inorganic carbon cycling in a low-order agricultural stream: implications for reach scales and beyond

    USGS Publications Warehouse

    Bohlke, Johnkarl F.; Tobias, Craig

    2011-01-01

    Movement of dissolved inorganic carbon (DIC) through the hydrologic cycle is an important component of global carbon budgets, but there is considerable uncertainty about the controls of DIC transmission from landscapes to streams, and through river networks to the oceans. In this study, diel measurements of DIC, d13C-DIC, dissolved oxygen (O2), d18O-O2, alkalinity, pH, and other parameters were used to assess the relative magnitudes of biological and geochemical controls on DIC cycling and flux in a nutrient-rich, net autotrophic stream. Rates of photosynthesis (P), respiration (R), groundwater discharge, air–water exchange of CO2, and carbonate precipitation/dissolution were quantified through a time-stepping chemical/isotope (12C and 13C, 16O and 18O) mass balance model. Groundwater was the major source of DIC to the stream. Primary production and carbonate precipitation were equally important sinks for DIC removed from the water column. The stream was always super-saturated with respect to carbonate minerals, but carbonate precipitation occurred mainly during the day when P increased pH. We estimated more than half (possibly 90%) of the carbonate precipitated during the day was retained in the reach under steady baseflow conditions. The amount of DIC removed from the overlying water through carbonate precipitation was similar to the amount of DIC generated from R. Air–water exchange of CO2 was always from the stream to the atmosphere, but was the smallest component of the DIC budget. Overall, the in-stream DIC reactions reduced the amount of CO2 evasion and the downstream flux of groundwater-derived DIC by about half relative to a hypothetical scenario with groundwater discharge only. Other streams with similar characteristics are widely distributed in the major river basins of North America. Data from USGS water quality monitoring networks from the 1960s to the 1990s indicated that 40% of 652 stream monitoring stations in the contiguous USA were at or above

  14. Effect of ditching operations on stream-water chemistry in a boreal forested catchment.

    PubMed

    Aström, M; Aaltonen, E K; Koivusaari, J

    2001-11-12

    The effects of ditching of boreal forest land on stream-water quality and quantity was assessed by comparing, over a 4-year-period, the physicochemical properties of the water in two small streams (western Finland), one whose catchment was ditched for forestry halfway through the sampling period and another nearby (control) stream whose catchment was not ditched ('paired catchment method'). While the artificial drainage did not have any significant effect on the hydrograph, it resulted in an increase in the aquatic concentrations of Mn, Ca, Mg, suspended material and alkalinity, a decrease in the concentrations of TOC and H3O+, while for Al and Fe there was a change in control mechanisms. The concentration and control changes after ditching are related to changes in hydrological pathways and to the exposure of both organic (peat) and inorganic (mineral soil) layers on the ditch slopes. PMID:11712589

  15. Assessment of selected inorganic constituents in streams in the Central Arizona Basins Study Area, Arizona and northern Mexico, through 1998

    USGS Publications Warehouse

    Anning, David W.

    2003-01-01

    Stream properties and water-chemistry constituent concentrations from data collected by the National Water-Quality Assessment and other U.S. Geological Survey water-quality programs were analyzed to (1) assess water quality, (2) determine natural and human factors affecting water quality, and (3) compute stream loads for the surface-water resources in the Central Arizona Basins study area. Stream temperature, pH, dissolved-oxygen concentration and percent saturation, and dissolved-solids, suspended-sediment, and nutrient concentration data collected at 41 stream-water quality monitoring stations through water year 1998 were used in this assessment. Water-quality standards applicable to the stream properties and water-chemistry constituent concentration data for the stations investigated in this study generally were met, although there were some exceedences. In a few samples from the White River, the Black River, and the Salt River below Stewart Mountain Dam, the pH in reaches designated as a domestic drinking water source was higher than the State of Arizona standard. More than half of the samples from the Salt River below Stewart Mountain Dam and almost all of the samples from the stations on the Central Arizona Project Canal?two of the three most important surface-water sources used for drinking water in the Central Arizona Basins study area?exceeded the U.S. Environmental Protection Agency drinking water Secondary Maximum Contaminant Level for dissolved solids. Two reach-specific standards for nutrients established by the State of Arizona were exceeded many times: (1) the annual mean concentration of total phosphorus was exceeded during several years at stations on the main stems of the Salt and Verde Rivers, and (2) the annual mean concentration of total nitrogen was exceeded during several years at the Salt River near Roosevelt and at the Salt River below Stewart Mountain Dam. Stream properties and water-chemistry constituent concentrations were related to

  16. Aquifer response to surface water transience in disconnected streams

    NASA Astrophysics Data System (ADS)

    Shanafield, Margaret; Cook, Peter G.; Brunner, Philip; McCallum, James; Simmons, Craig T.

    2012-11-01

    Existing analytical solutions to determine aquifer response to a change in stream stage are inappropriate where an unsaturated zone exists beneath the stream, as in the case of disconnected stream-aquifer systems. A better understanding of the relationship between aquifer response and transient stream stage in disconnected systems is therefore required, as this would also aid in the field determination of the status of connection between the stream and aquifer. We use a numerical model to examine transient stream stage and the corresponding water table response. Beneath disconnected streams, the magnitude of head change in the water table level is a balance between the cumulative infiltration during a flow event and the rate at which the water can disperse laterally. Increases in wave duration, stream width, and streambed permeability result in greater infiltrated water volume and therefore a higher peak response at the water table. Conversely, higher aquifer transmissivity and aquifer hydraulic conductivity allow the water to move laterally away from the stream faster, resulting in a smaller head change below the stream. Lower unsaturated storage results in a greater and faster aquifer response because the unsaturated zone can fill more quickly. Under some combinations of parameters, the magnitude of the disconnected head response is more than seven times greater than the change in stream stage driving streambed infiltration; an effect which can never occur beneath a connected stream. The results of this sensitivity analysis are compared to field data from a river in eastern Australia to determine periods of disconnection. Where the change in aquifer head is greater than the change in stream stage, disconnection between the stream and aquifer can be determined.

  17. Slip stream apparatus and method for treating water in a circulating water system

    DOEpatents

    Cleveland, Joe R.

    1997-01-01

    An apparatus (10) for treating water in a circulating water system (12) t has a cooling water basin (14) includes a slip stream conduit (16) in flow communication with the circulating water system (12), a source (36) of acid solution in flow communication with the slip stream conduit (16), and a decarbonator (58) in flow communication with the slip stream conduit (16) and the cooling water basin (14). In use, a slip stream of circulating water is drawn from the circulating water system (12) into the slip stream conduit (16) of the apparatus (10). The slip stream pH is lowered by contact with an acid solution provided from the source (36) thereof. The slip stream is then passed through a decarbonator (58) to form a treated slip stream, and the treated slip stream is returned to the cooling water basin (14).

  18. Slip stream apparatus and method for treating water in a circulating water system

    DOEpatents

    Cleveland, J.R.

    1997-03-18

    An apparatus is described for treating water in a circulating water system that has a cooling water basin which includes a slip stream conduit in flow communication with the circulating water system, a source of acid solution in flow communication with the slip stream conduit, and a decarbonator in flow communication with the slip stream conduit and the cooling water basin. In use, a slip stream of circulating water is drawn from the circulating water system into the slip stream conduit of the apparatus. The slip stream pH is lowered by contact with an acid solution provided from the source thereof. The slip stream is then passed through a decarbonator to form a treated slip stream, and the treated slip stream is returned to the cooling water basin. 4 figs.

  19. The Role of Stream Water Carbon Dynamics and Export in the Carbon Balance of a Tropical Seasonal Rainforest, Southwest China

    PubMed Central

    Zhou, Wen-Jun; Zhang, Yi-Ping; Schaefer, Douglas A.; Sha, Li-Qing; Deng, Yun; Deng, Xiao-Bao; Dai, Kai-Jie

    2013-01-01

    A two-year study (2009 ∼ 2010) was carried out to investigate the dynamics of different carbon (C) forms, and the role of stream export in the C balance of a 23.4-ha headwater catchment in a tropical seasonal rainforest at Xishuangbanna (XSBN), southwest China. The seasonal volumetric weighted mean (VWM) concentrations of total inorganic C (TIC) and dissolved inorganic C (DIC) were higher, and particulate inorganic C (PIC) and organic C (POC) were lower, in the dry season than the rainy season, while the VWM concentrations of total organic C (TOC) and dissolved organic C (DOC) were similar between seasons. With increased monthly stream discharge and stream water temperature (SWT), only TIC and DIC concentrations decreased significantly. The most important C form in stream export was DIC, accounting for 51.8% of the total C (TC) export; DOC, POC, and PIC accounted for 21.8%, 14.9%, and 11.5% of the TC export, respectively. Dynamics of C flux were closely related to stream discharge, with the greatest export during the rainy season. C export in the headwater stream was 47.1 kg C ha−1 yr−1, about 2.85% of the annual net ecosystem exchange. This finding indicates that stream export represented a minor contribution to the C balance in this tropical seasonal rainforest. PMID:23437195

  20. Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange

    USGS Publications Warehouse

    Harvey, J.W.; Wagner, B.J.; Bencala, K.E.

    1996-01-01

    Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub- reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) and reachscale modeling of in- stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones (stream tracer approach). Subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange. The reach-averaged hyporheic exchange flux (1.5 mL s-1 m-1), determined by hydrometric methods, was largest when stream base flow was low (10 L s-1); hyporheic exchange persisted when base flow was 10- fold higher, decreasing by approximately 30%. Reliability of the stream tracer approach to detect hyporheic exchange was assessed using first- order uncertainty analysis that considered model parameter sensitivity. The stream tracer approach did not reliably characterize hyporheic exchange at high base flow: the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone. At low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed (timescale of hours) but was relatively insensitive to slower exchange with deeper alluvium (timescale of tens of hours) that was detected by subsurface measurements. The stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange. We conclude that while the stream tracer approach is an efficient means to characterize surface-subsurface exchange, future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward

  1. Evaluating the Reliability of the Stream Tracer Approach to Characterize Stream-Subsurface Water Exchange

    NASA Astrophysics Data System (ADS)

    Harvey, Judson W.; Wagner, Brian J.; Bencala, Kenneth E.

    1996-08-01

    Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub-reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) and reachscale modeling of in-stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones (stream tracer approach). Subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange. The reach-averaged hyporheic exchange flux (1.5 mL s-1 m-1), determined by hydrometric methods, was largest when stream base flow was low (10 L s-1); hyporheic exchange persisted when base flow was 10-fold higher, decreasing by approximately 30%. Reliability of the stream tracer approach to detect hyporheic exchange was assessed using first-order uncertainty analysis that considered model parameter sensitivity. The stream tracer approach did not reliably characterize hyporheic exchange at high base flow: the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone. At low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed (timescale of hours) but was relatively insensitive to slower exchange with deeper alluvium (timescale of tens of hours) that was detected by subsurface measurements. The stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange. We conclude that while the stream tracer approach is an efficient means to characterize surface-subsurface exchange, future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward

  2. ENHANCED STREAM WATER QUALITY MODEL (QUAL2EU)

    EPA Science Inventory

    The enhanced stream water quality model QUAL2E and QUAL2E-UNCAS (37) permits simulation of several water quality constituents in a branching stream system using a finite difference solution to the one-dimensional advective-dispersive mass transport and reaction equation. The con...

  3. Comparative assessment of water treatment using polymeric and inorganic coagulants

    NASA Astrophysics Data System (ADS)

    Manda, Innocent K. M.; Chidya, Russel C. G.; Saka, John D. K.; Biswick, Timothy T.

    2016-06-01

    Portable water plays a vital role in improving human life, particularly in controlling the spread of diseases. However, problems associated with lack of potable water are still common especially in developing countries including Malawi. Until now little information exists on the effectiveness of available commercial coagulants used by national water boards in Malawi. Therefore, this study was undertaken in Southern Region Water Board (SRWB) to investigate the efficiency of polymeric coagulants (sufdfloc 3850 and algaefloc 19s) in turbidity reduction comparative with inorganic coagulant (aluminium sulphate) at Zomba, Liwonde, Mangochi, Chikwawa and Mulanje Treatment plants. The jar test method was used to determine the effectiveness of the water coagulants. The results revealed that sudfloc 3850 was most effective in reducing turbidity at Mangochi (99.4 ± 0.06%) and Liwonde (97.2 ± 0.04%) using 0.4 mg L-1 flocculant dose. The Zomba, Mulanje and Chikwawa plants gave 19.56 ± 0.03%, 29.23 ± 0.02% and 9.43 ± 0.02% total reductions respectively. Algaefloc 19s afforded the highest turbidity reduction at Liwonde and Mangochi plants (98.66 ± 0.06 and 97.48 ± 0.05% at a dose of 0.4 and 0.6 mg L-1 respectively), while Chikwawa provided the lowest (9.52 ± 0.01%). At the Zomba and Mulanje plants 20.5 ± 0.03% and 28.4 ± 0.04% reductions were obtained respectively. The inorganic flocculant, alum provided a 99.0 ± 0.05% and 98.6 ± 0.04% reduction at a dose of 4.0 mg L-1 and 6.0 mg L-1 at Zomba and Liwonde plants respectively. The lowest reductions in turbidity were achieved at Chikwawa (7.50 ± 0.01%), Mangochi (12.97 ± 0.02%) and Mulanje (25.00 ± 0.02). The best and optimum pH ranges for polymeric and inorganic coagulants were 7.20-7.80 and 7.35 to 7.57 respectively. The results further revealed that sudfloc 3850 and algaefloc 19s achieved faster formation of heavy flocs than alum. At 0.4 mg L-1 flocculant dosage sudfloc 3850 and algaefloc 19s required ten times

  4. Active Layer Thermal Response to Stream Water Temperatures

    NASA Astrophysics Data System (ADS)

    Cozzetto, K.; McKnight, D.

    2004-12-01

    The hyporheic zone is comprised of sediments below and adjacent to a stream through which stream water flows in and out. In polar regions, the shape, dimensions, physical and chemical characteristics of this zone are affected by the seasonal freezing and thawing of the active layer. One factor that may influence the active layer temperature regime is stream water temperature, both its absolute value and cyclic variations in its value. Many of the glacial meltwater streams in Taylor Valley in the McMurdo Dry Valleys of Antarctica, exhibit daily temperature patterns with lows of 0 or 1° C and highs of 10 or, on occasion, 15° C. Because the viscosity of water decreases significantly with increasing temperature, these daily maxima may increase infiltration and the exchange of water and heat between the stream and the hyporheic zone. To investigate the influence of stream water temperature and flow paths on the active layer temperature regime and vice versa, two conservative tracer injection experiments were conducted. Both took place in the same 200-meter reach, which was instrumented with temperature and conductivity probes. Both also took place at the same time of day during which the stream reaches its temperature maximum. However, in one experiment snow from a nearby patch was added to the stream to suppress the temperature maximum by 3° C from 10 to 7° C. The temperature data show that the snow addition slowed the rate of hyporheic zone warming and suppressed temperature increases in the hyporheic zone by 1-3° C when compared with the non-perturbation experiment. The electrical conductivity data indicate that during the snow addition experiment, the stream neither gained nor lost water while during the non-perturbation experiment, the stream lost water. These results suggest that the stream water cooling decreased infiltration and heat transfer into the hyporheic zone.

  5. Long-Term Data Reveal Patterns and Controls on Stream Water Chemistry in a Forested Stream: Walker Branch, Tennessee

    SciTech Connect

    Lutz, Brian D; Mulholland, Patrick J; Bernhardt, Emily

    2012-01-01

    We present 20 years of weekly stream water chemistry, hydrology, and climate data for the Walker Branch watershed in eastern Tennessee, USA. Since 1989, the watershed has experienced a similar to 1.08 degrees C increase in mean annual temperature, a similar to 20% decline in precipitation, and a similar to 30% increase in forest evapotranspiration rates. As a result, stream runoff has declined by similar to 34%. We evaluate long-term trends in stream water concentrations and fluxes for nine solutes and use wet deposition data to calculate approximate watershed input-output budgets. Dissolved constituents were classified as geochemical solutes (Ca2+, Mg2+, and SO42-) or nutrients (NH4+, NO3-, soluble reactive phosphorus [SRP], total soluble nitrogen [TSN], total soluble phosphorus [TSP], and dissolved organic carbon [DOC]). Geochemical solutes are predominantly controlled by discharge, and the long-term changes in catchment hydrology have led to significant trends in the concentrations and fluxes of these solutes. Further, the trends in geochemical solute concentrations indicate shifting soil flowpath contributions to streamflow generation through time, with deep groundwater having a greater proportional contribution in recent years. Despite dramatic changes in watershed runoff, there were no trends in inorganic nutrient concentrations (NH4+, NO3-, and SRP). While most nutrients entering the watershed are retained, stream fluxes of nutrient solutes have declined significantly as a result of decreasing runoff. Nutrient concentrations in the stream exhibit large seasonality controlled by in-stream biological uptake. Stream benthic communities are sensitive to hydrologic disturbance, and changes in the frequency or intensity of storm events through time can affect nutrient fluxes. Stream NO3- concentrations are also sensitive to drought, with concentrations decreasing (increasing) if conditions during the three years prior to the time of sampling were drier (wetter

  6. The effect of broadleaf woodland on aluminium speciation in stream water in an acid-sensitive area in the UK.

    PubMed

    Ryan, Jennifer L; Lynam, Philippa; Heal, Kate V; Palmer, Sheila M

    2012-11-15

    Acidification can result in the mobilisation and release of toxic inorganic monomeric aluminium (Al) species from soils into aquatic ecosystems. Although it is well-established that conifer trees enhance acidic atmospheric deposition and exacerbate soil and water acidification, the effect of broad-leaved woodland on soil and water acidification is less clear. This study investigated the effect of broadleaf woodland cover on the acid-base chemistry and Al species present in stream water, and processes controlling these in the acid-sensitive area around Loch Katrine, in the central Highlands, Scotland, UK, where broadleaf woodland expansion is occurring. A nested sampling approach was used to identify 22 stream sampling locations, in sub-catchments of 3.2-61 ha area and 0-45% broadleaf woodland cover. In addition, soils sampled from 68 locations were analysed to assess the influence of: (i) broadleaf woodland cover on soil characteristics and (ii) soil characteristics on stream water chemistry. Stream water pH was negatively correlated with sub-catchment % woodland cover, indicating that woodland cover is enhancing stream water acidification. Concentrations of all stream water Al species (monomeric total, organic and inorganic) were positively correlated with % woodland cover, although not significantly, but were below levels that are toxic to fish. Soil depth, O horizon depth and soil chemistry, particularly of the A horizon, appeared to be the dominant controls on stream water chemistry rather than woodland cover. There were significant differences in soil acid-base chemistry, with significantly lower O horizon pH and A horizon base saturation and higher A horizon exchangeable Al in the wooded catchments compared to the control. This is evidence that the mobile anion effect is already occurring in the study catchments and suggests that stream water acidification arising from broadleaf woodland expansion could occur, especially where tree density is high and acid

  7. Distribution, behavior, and transport of inorganic and methylmercury in a high gradient stream

    USGS Publications Warehouse

    Flanders, J.R.; Turner, R.R.; Morrison, T.; Jensen, R.; Pizzuto, J.; Skalak, K.; Stahl, R.

    2010-01-01

    Concentrations of Hg remain elevated in physical and biological media of the South River (Virginia, USA), despite the cessation of the industrial use of Hg in its watershed nearly six decades ago, and physical characteristics that would not seem to favor Hg(II)-methylation. A 3-a study of inorganic Hg (IHg) and methylmercury (MeHg) was conducted in physical media (soil, sediment, surface water, porewater and soil/sediment extracts) to identify non-point sources, transport mechanisms, and potential controls on Hg(II)-methylation. Data collected from surface water and sediment indicate that the majority of the non-point sources of IHg to the South River are within the first 14. km downstream from the historic point source. Partitioning data indicate that particle bound IHg is introduced in this reach, releasing dissolved and colloidal bound IHg, which is transported downstream. Extraction experiments revealed that floodplain soils released a higher fraction of their IHg content in aqueous extractions than fine-grained sediment (FGS). Based on ultrafiltration [<5000 nominal molecular weight cutoff (NMWC)] the majority of soil IHg released was colloidal in nature, providing evidence for the continued evolution of IHg for Hg(II)-methylation from soil. Strong seasonal patterns in MeHg concentrations were observed in surface water and sediment. The highest concentrations of MeHg in surface water were observed at moderate temperatures, suggesting that other factors limit net Hg(II)-methylation. Seasonal changes in sediment organic content and the fraction of 1. N KOH-extractable THg were also observed and may be important factors in controlling net Hg(II)-methylation rates. Sulfate concentrations in surface water are low and the evidence suggests that Fe reduction may be an important Hg(II)-methylation process. The highest sediment MeHg concentrations were observed in habitats with large amounts of FGS, which are more prevalent in the upper half of the study area due to

  8. Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water

    PubMed Central

    Carey, Manus; Jiujin, Xiao; Gomes Farias, Júlia; Meharg, Andrew A.

    2015-01-01

    A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery. PMID:26200355

  9. Rethinking Rice Preparation for Highly Efficient Removal of Inorganic Arsenic Using Percolating Cooking Water.

    PubMed

    Carey, Manus; Jiujin, Xiao; Gomes Farias, Júlia; Meharg, Andrew A

    2015-01-01

    A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery. PMID:26200355

  10. Contaminant Sources in Stream Water of a Missouri Claypan Watershed

    NASA Astrophysics Data System (ADS)

    Peters, G. R.; Liu, F.; Lerch, R. N.; Lee, H.

    2014-12-01

    Elevated concentrations of nitrate-nitrogen and herbicides in stream water have degraded water quality and caused serious problems affecting human and aquatic ecosystem health in the Central Claypan Region of the US Midwest. However, the contribution of specific recharge sources to stream water is not well understood in claypan-dominated watersheds. The purpose of this study was to estimate the recharge sources to Goodwater Creek Experimental Watershed (GCEW) in north-central Missouri and investigate their importance to contaminant transport. Samples were collected from 2011 to 2014 from streams, piezometers, seep flows, and groundwater in GCEW and analyzed for major ions (including nitrate and nitrite), trace elements, stable H and O isotopes, total nitrogen (TN) and herbicides. Using an endmember mixing analysis based on conservative tracers, recharge contributions to stream flow were an average of 25% surface runoff, 44% shallow subsurface water, and 31% groundwater. TN concentrations were, on average, <0.05 ppm, 0.5 ppm, and 5 ppm in surface runoff, shallow subsurface water, and groundwater, respectively. Atrazine concentrations were, on average, <0.001 ppb, 0.052 ppb and <0.0001 in surface runoff, shallow subsurface water and groundwater, respectively. The data indicated that TN in stream water was primarily from groundwater, while shallow subsurface water was the dominant source of atrazine in stream water. An improved understanding of claypan hydrology and contaminant transport could lead to crop management practices that better protect surface water and groundwater in claypan-dominated watersheds.

  11. Field tests of diffusion samplers for inorganic constituents in wells and at a ground-water discharge zone

    USGS Publications Warehouse

    Vroblesky, Don A.; Petkewich, Matthew D.; Campbell, Ted R.

    2002-01-01

    Field tests were performed on two types of diffusion samplers to collect representative samples of inorganic constituents from ground water in wells and at an arsenic-contaminated ground-water-discharge zone beneath a stream. Nylon-screen samplers and dialysis samplers were tested for the collection of arsenic, calcium, chloride, iron, manganese, sulfate, and dissolved oxygen. The investigations were conducted at the Naval Industrial Reserve Ordnance Plant (NIROP), Fridley, Minnesota, and at the Naval Air Station Fort Worth Joint Reserve Base (NAS Fort Worth JRB), Texas. Data indicate that, in general, nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water that correspond to concentrations obtained by low-flow sampling. Diffusion samplers offer a potentially time-saving approach to well sampling. Particular care must be taken, however, when sampling for iron and other metals, because of the potential for iron precipitation by oxygenation and when dealing with chemically stratified sampling intervals. Simple nylon-screen jar samplers buried beneath creekbed sediment appear to be effective tools for locating discharge zones of arsenic contaminated ground water. Although the LDPE samplers have proven to be inexpensive and simple to use in wells, they are limited by their inability to provide a representative sample of ionic solutes. The success of nylon-screen samplers in sediment studies suggests that these simple samplers may be useful for collecting water samples for inorganic constituents in wells. Results using dialysis bags deployed in wells suggest that these types of samplers have the potential to provide a representative sample of both VOCs and ionic solutes from ground water (Kaplan and others, 1991; Theodore A. Ehlke, U.S. Geological Survey, written commun., 2001). The purpose of this report is to provide results of field tests investigating the potential to use diffusion samplers to collect

  12. Sediment-water partitioning of inorganic mercury in estuaries.

    PubMed

    Turner, A; Millward, G E; Le Roux, S M

    2001-12-01

    The sediment-water partitioning and speciation of inorganic mercury have been studied under simulated estuarine conditions by monitoring the hydrophobicity and uptake of dissolved 203Hg(II) in samples from a variety of estuarine environments. A persistent increase in the distribution coefficientwith increasing salinity is inconsistent with inorganic speciation calculations, which predict an increase in the concentration of the soluble HgCl4(2-) complex (or reduction in sediment-water distribution coefficient) with increasing salinity. Partition data are, however, defined by an empirical equation relating to the salting out of nonelectrolytes via electrostriction and are characterized by salting constants between about 1.4 and 2.0 L mol(-1). Salting out of the neutral, covalent chloro-complex, HgCl2(0), is predicted but cannot account for the magnitude of salting out observed. Since Hg(II) strongly complexes with dissolved (and particulate) organic matter in natural environments, of more significance appears to be the salting out of Hg(II)-organic complexes. Operational measurements of the speciation of dissolved Hg(II) using Sep-Pak C18 columns indicate a reduction in the proportion of hydrophobic (C18-retained) dissolved Hg(II) complexes with increasing salinity, both in the presence and absence of suspended particles. Ratios of hydrophobic Hg(ll) before and after particle addition suggest a coupled salting out-sorption mechanism, with the precise nature of Hg(II) species salted out being determined bythe characteristics and concentrations of dissolved and sediment organic matter. PMID:11770766

  13. Waste stream recycling: Its effect on water quality

    SciTech Connect

    Cornwell, D.A. ); Lee, R.G. )

    1994-11-01

    Waste streams recycled to the influent of a water treatment plant typically contain contaminants at concentrations that are of concern. These contaminants may include giardia and Cryptosporidium, trihalomethanes, manganese, and assimilable organic carbon. This research shows that proper management--treatment, equalization, and monitoring--of the waste streams can render them suitable for recycling in many situations.

  14. Effect of stream acidification and inorganic aluminum on mortality of brook trout (Salvelinus fontinalis) in the Catskill Mountains, New York

    USGS Publications Warehouse

    Baldigo, Barry P.; Murdoch, Peter S.

    1997-01-01

    Juvenile brook trout (Salvelinus fontinalis) were exposed in cages to fluctuating chemical conditions in four Catskill Mountain streams during the spring and fall of 1989 and the spring of 1990. Specific chemical constituents and characteristics of acidic episodes that correlated with increased fish mortality were identified. Mortality increased during acidic episodes in one poorly buffered stream when inorganic monomeric aluminum (Al(im)) concentrations increased; mortality was low in three other streams during acidic episodes of shorter duration and smaller magnitude than measured in the poorly buffered stream. Variation in mortality was attributed primarily to differences in concentrations of both Al(im) and dissolved organic carbon. Linear and logistic regression analyses indicate that either mean or median Al(im) concentrations could account for 73-99% of the variability in mortality. Regression analyses suggest that mortality was highly related (in order of importance) to Al(im), pH, dissolved organic carbon, calcium, and chloride concentration. Brook trout mortality was also highly related to durations of exposure above 0.225 and 0.250 mg/L Al(im) during test periods. Characteristics of acidic-Al(im) episodes that are critical to mortality of caged brook trout appear to be (i) Al(im) concentrations of at least 0.225 ?? 0.025 mg/L and (ii) exposure to these toxic Al(im) concentrations for at least 2 days.

  15. ASSESSMENT OF NEAR-STREAM GROUND WATER-SURFACE WATER INTERACTION (GSI) OF A DEGRADED STREAM BEFORE RESTORATION

    EPA Science Inventory

    In Fall 2001, EPA undertook an intensive collaborative research effort with the USGS and the Institute of Ecosystem Studies (IES) to evaluate the impact of restoration on water quality at a degraded stream in an urban watershed using a before/after stream restoration study design...

  16. Tundra fire alters stream water chemistry and benthic invertebrate communities, North Slope, Alaska

    NASA Astrophysics Data System (ADS)

    Allen, A. R.; Bowden, W. B.; Kling, G. W.; Schuett, E.; Kostrzewski, J. M.; Kolden Abatzoglou, C.; Findlay, R. H.

    2010-12-01

    Increased fire frequency and severity are potentially important consequences of climate change in high latitude ecosystems. The 2007 Anaktuvuk River fire, which burned from July until October, is the largest recorded tundra fire from Alaska's north slope (≈1,000 km2). The immediate effects of wildfire on water chemistry and biotic assemblages in tundra streams are heretofore unknown. We hypothesized that a tundra fire would increase inorganic nutrient inputs to P-limited tundra streams, increasing primary production and altering benthic macroinvertebrate community structure. We examined linkages among: 1) percentage of riparian zone and overall watershed vegetation burned, 2) physical, chemical and biological stream characteristics, and 3) macroinvertebrate communities in streams draining burned and unburned watersheds during the summers of 2008 and 2009. Streams in burned watersheds contained higher mean concentrations of soluble reactive phosphorus (SRP), ammonium (NH4+), and dissolved organic carbon (DOC). In contrast, stream nitrate (NO3-) concentrations were lower in burned watersheds. The net result was that the tundra fire did not affect concentrations of dissolved inorganic nitrogen (NH4+ + NO3-). In spite of increased SRP, benthic chlorophyll-a biomass was not elevated. Macroinvertebrate abundances were 1.5 times higher in streams draining burned watersheds; Chironomidae midges, Nematodes, and Nemoura stoneflies showed the greatest increases in abundance. Multivariate multiple regression identified environmental parameters associated with the observed changes in the macroinvertebrate communities. Since we identified stream latitude as a significant predictor variable, latitude was included in the model as a covariate. After removing the variation associated with latitude, 67.3 % of the variance in macroinvertebrate community structure was explained by a subset of 7 predictor variables; DOC, conductivity, mean temperature, NO3-, mean discharge, SRP and NH

  17. Recreational stream assessment using Malaysia water quality index

    NASA Astrophysics Data System (ADS)

    Ibrahim, Hanisah; Kutty, Ahmad Abas

    2013-11-01

    River water quality assessment is crucial in order to quantify and monitor spatial and temporally. Malaysia is producing WQI and NWQS indices to evaluate river water quality. However, the study on recreational river water quality is still scarce. A study was conducted to determine selected recreational river water quality area and to determine impact of recreation on recreational stream. Three recreational streams namely Sungai Benus, Sungai Cemperuh and Sungai Luruh in Janda Baik, Pahang were selected. Five sampling stations were chosen from each river with a 200-400 m interval. Six water quality parameters which are BOD5, COD, TSS, pH, ammoniacal-nitrogen and dissolved oxygen were measured. Sampling and analysis was conducted following standard method prepared by USEPA. These parameters were used to calculate the water quality subindex and finally an indicative WQI value using Malaysia water quality index formula. Results indicate that all recreational streams have excellent water quality with WQI values ranging from 89 to 94. Most of water quality parameter was homogenous between sampling sites and between streams. An one-way ANOVA test indicates that no significant difference was observed between each sub index values (p> 0.05, α=0.05). Only BOD and COD exhibit slightly variation between stations that would be due to organic domestic wastes done by visitors. The study demonstrated that visitors impact on recreational is minimum and recreation streams are applicable for direct contact recreational.

  18. Use of arsenic-73 in research supports USEPA's regulatory decisions on inorganic arsenic in drinking water*

    EPA Science Inventory

    Inorganic arsenic is a natural contaminant of drinking water in the United States and throughout the world. Long term exposure to inorganic arsenic in drinking water at elevated levels (>100 ug/L) is associated with development of cancer in several organs, cardiovascular disease,...

  19. The Role of Headwater Streams in Downstream Water Quality1

    PubMed Central

    Alexander, Richard B; Boyer, Elizabeth W; Smith, Richard A; Schwarz, Gregory E; Moore, Richard B

    2007-01-01

    Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and

  20. The effect of variable discharge on the inorganic chemistry downstream of a waste water treatment plant, Boulder Creek, Colorado

    NASA Astrophysics Data System (ADS)

    Antweiler, R. C.; Writer, J. H.; Murphy, S. F.

    2012-12-01

    Researchers investigating the effect of wastewater treatment plant (WWTP) effluent on streams often assume that the magnitude of this effect is constant over time. However, discharge of WWTP effluent frequently follows a distinctive diel pattern. WWTP effluent discharge into Boulder Creek, Colorado, for example, varies by almost 200% over the course of a day. Due to this variation, downstream concentrations of chloride, boron and gadolinium (commonly used "conservative tracers") exhibit major changes over a 24-hour period. In order to determine how effluent discharge variability affects stream chemistry, we performed an evaluation of discharge and inorganic chemistry of the City of Boulder's WWTP and Boulder Creek upstream and downstream of the WWTP (representing a 5.4-km reach). Sodium bromide and Rhodamine WT were used to confirm that the same parcel of water was sampled as it moved downstream. The behavior of inorganic constituents fell into three distinct categories, showing conservative behavior, in-stream loss, or in-stream gain. Accounting for variable effluent discharge, the following inorganic constituents behaved conservatively: Cl, SO4, HCO3, F, B, Ba, Ca, Gd, K, Mg, Rb, Co, Cu, Mo, NO3, P and PO4, Sb, SiO2, Sr and Zn. Inorganic compounds which showed evidence of in-stream loss were Bi, Cr, Cs, Ga, Ge, Hg, Se, and Sn. For these elements, the typical pattern was an almost immediate loss: by the time the water had traveled to the first downstream sampling site, 2.3-km below the WWTP, in-stream reactions appeared to have ceased, and a constant flux was observed at all subsequent sites. We speculate that the near-immediate rates represent precipitation and/or adsorption caused by the change in pH and temperature of the mixing zone. Inorganic constituents that showed evidence of in-stream gain were: Al, As, Cd, Fe, I, Li, Mn, Nb, Pb, Re, Th, U, V, W, and all the rare-earth elements (except Gd). As with the in-stream loss group, most of the reactions occurred

  1. Chemistry of Stream Sediments and Surface Waters in New England

    USGS Publications Warehouse

    Robinson, Gilpin R., Jr.; Kapo, Katherine E.; Grossman, Jeffrey N.

    2004-01-01

    Summary -- This online publication portrays regional data for pH, alkalinity, and specific conductance for stream waters and a multi-element geochemical dataset for stream sediments collected in the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. A series of interpolation grid maps portray the chemistry of the stream waters and sediments in relation to bedrock geology, lithology, drainage basins, and urban areas. A series of box plots portray the statistical variation of the chemical data grouped by lithology and other features.

  2. Heavy metal accumulations in water, sediment, and some cyprinid species in Porsuk Stream (Turkey).

    PubMed

    Köse, Esengül; Çiçek, Arzu; Uysal, Kazim; Tokatlı, Cem; Emiroğlu, Özgür; Arslan, Naime

    2015-03-01

    Porsuk Stream is one of Turkey's most important river systems and also one of the most important branches of the Sakarya River. It provides drinking and utility water for two Turkish cities (Kütahya and Eskişehir) with a total population of one million. In this study, water, sediment, and some tissues (liver, gill, and muscle) of five cyprinid fish species were collected seasonally (2010-2011) from eight stations on the Porsuk Stream, and the zinc (Zn), copper (Cu), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), and arsenic (As) levels of collected samples were determined. The data observed were evaluated with national and international quality criteria. Based on the data observed, it was determined that the Porsuk Stream is affected by significant inorganic pollution from the Kütahya and Eskişehir Provinces. It was also determined that the Porsuk Dam Lake has an important cleaning capacity and that the water and sediment quality of the Porsuk Stream improves after the output of the dam lake. PMID:25842529

  3. Mercury cycling in stream ecosystems. 2. Benthic methylmercury production and bed sediment - Pore water partitioning

    USGS Publications Warehouse

    Marvin-DiPasquale, M.; Lutz, M.A.; Brigham, M.E.; Krabbenhoft, D.P.; Aiken, G.R.; Orem, W.H.; Hall, B.D.

    2009-01-01

    Mercury speciation, controls on methylmercury (MeHg) production, and bed sediment - pore water partitioning of total Hg (THg) and MeHg were examined in bed sediment from eight geochemically diverse streams where atmospheric deposition was the predominant Hg input. Across all streams, sediment THg concentrations were best described as a combined function of sediment percent fines (%fines; particles < 63 ??m) and organic content. MeHg concentrations were best described as a combined function of organic content and the activity of the Hg(II)-methylating microbial community and were comparable to MeHg concentrations in streams with Hg inputs from industrial and mining sources. Whole sediment tin-reducible inorganic reactive Hg (Hg(II)R) was used as a proxy measure for the Hg(II) pool available for microbial methylation. In conjunction with radiotracer-derived rate constants of 203Hg(II) methylation, Hg(II)R was used to calculate MeHg production potential rates and to explain the spatial variability in MeHg concentration. The %Hg(II)R (of THg) was low (2.1 ?? 5.7%) and was inversely related to both microbial sulfate reduction rates and sediment total reduced sulfur concentration. While sediment THg concentrations were higher in urban streams, %MeHg and %Hg(II)R were higher in nonurban streams. Sediment pore water distribution coefficients (log Kd's) for both THg and MeHg were inversely related to the log-transformed ratio of pore water dissolved organic carbon (DOC) to bed sediment %fines. The stream with the highest drainage basin wetland density also had the highest pore water DOC ?? 2009 American Chemical Society.

  4. Impact of a hydrophobic granular stream in water

    NASA Astrophysics Data System (ADS)

    Utter, Brian; Mandeles, Harry; Parkhouse, Jacob

    We experimentally investigate the flow of a stream of hydrophobic granular particles impacting a water surface from above. The granular sample is composed of a mixture of hydrophobic and hydrophilic grains and the concentration, stream diameter, and drop height are independently controlled. While granular flows are common in nature and industry, effects of surface chemistry on flow behavior have received relatively little attention. The present experiment complements rheological measurements performed in parallel and aims to elucidate prior experiments on hydrophobic samples in a rotating drum. The present experimental geometry allows us to compare the behavior of granular streams to prior work on impacts of solids and fluid streams. Sequential images of the granular stream in water are taken and analyzed. We present data on the size, length, and shape of the aggregate streams with variations in concentration, entering stream diameter, and drop height. We find that increased hydrophobic grain concentration leads to increased aggregation due to an effectively cohesive interaction mediated by entrained air. At lower concentrations, the stream exhibits a lateral instability. Finally, we will make connections to rheology and rotating drum results. This work was supported by NSF CBET award 1067598.

  5. Indirect gas chromatographic measurement of water for process streams

    SciTech Connect

    Barbour, F.A.

    1993-05-01

    This project was conducted to develop a moisture measurement method for process gas streams of fossil fuels. Objective was to from pyrolysis to measure the molar concentration of water in a gas stream without flow measurements. The method developed has been incorporated into the hydrocarbon gas analysis method currently used at Western Research Institute. A literature search of types of direct measuring moisture sensors was conducted, and a list of sensors available is given; most of them could not survive in the environment of the process streams. Indirect methods of measuring water involve changing the water via reaction to a compound that can be more readily measured. These methods react water with various reagents to form hydrogen, acetylene, and acetone. The method chose for this study uses a calcium carbide reaction column to convert the water present in the gas stream to acetylene for analysis. Relative deviation for the daily determination of water varied from 0.5 to 3.4%. The method chosen was tested for linearity over a wide range of gas stream water content. Response over 2 to 15 mole % water appears to be linear with a correlation coefficient of 0.991.

  6. Effects of sewage effluents on water quality in tropical streams.

    PubMed

    Figueroa-Nieves, Débora; McDowell, William H; Potter, Jody D; Martínez, Gustavo; Ortiz-Zayas, Jorge R

    2014-11-01

    Increased urbanization in many tropical regions has led to an increase in centralized treatment of sewage effluents. Research regarding the effects of these wastewater treatment plants (WWTPs) on the ecology of tropical streams is sparse, so we examined the effects of WWTPs on stream water quality on the Caribbean island of Puerto Rico. Nutrient concentrations, discharge, dissolved oxygen (DO), biochemical oxygen demand (CBOD), and specific UV absorbance (SUVA) at 254 nm were measured upstream from the WWTP effluent, at the WWTP effluent, and below the WWTP effluent. All parameters measured (except DO) were significantly affected by discharge of WWTP effluent to the stream. The values of SUVA at 254 nm were typically lower (<2.5 m mg L) in WWTP effluents than those measured upstream of the WWTP, suggesting that WWTP effluents are contributing labile carbon fractions to receiving streams, thus changing the chemical composition of dissolved organic carbon in downstream reaches. Effluents from WWTP contributed on average 24% to the stream flow at our tropical streams. More than 40% of the nutrient loads in receiving streams came from WWTP effluents, with the effects on NO-N and PO-P loads being the greatest. The effect of WWTPs on nutrient loads was significantly larger than the effect of flow due to the elevated nutrient concentrations in treated effluents. Our results demonstrate that inputs from WWTPs to streams contribute substantially to changes in water quality, potentially affecting downstream ecosystems. Our findings highlight the need to establish nutrient criteria for tropical streams to minimize degradation of downstream water quality of the receiving streams. PMID:25602222

  7. Treatment Technology to Meet the Interim Primary Drinking Water Regulations for Inorganics: Part 3.

    ERIC Educational Resources Information Center

    Sorg, Thomas J.; And Others

    1978-01-01

    This article is the third in a series summarizing existing treatment technology to meet the inorganic National Interim Primary Drinking Water Regulations. This report deals specifically with treatment methods for removing cadmium, lead, and silver from drinking water. (CS)

  8. ASSESSING THE ROLE OF NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUND WATER

    EPA Science Inventory

    Monitored natural attenuation (MNA) has been applied as a knowledge-based remediation technology for organic contaminants in ground water. The application of this technology is being considered for remediation of inorganic contaminants in ground water at hazardous waste sites. ...

  9. MONITORED NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUND WATER: MNA MECHANISMS

    EPA Science Inventory

    This presentation discusses the various mechanisms that are recognized to result in the attenuation of inorganic contaminants in ground water. The presentation will provide details on the contaminant sequestration processes that occur at the mineral-water interface.

  10. Inorganic Analyses in Water Quality Control Programs. Training Manual.

    ERIC Educational Resources Information Center

    Kroner, Audrey; And Others

    This lecture/laboratory manual for a five-day course deals with the analysis of selected inorganic pollutants. The manual is an instructional aid for classroom presentations to those with little or no experience in the field, but having one year (or equivalent) of college level inorganic chemistry, one semester of college level quantitative…

  11. Inorganic Analyses in Water Quality Control Programs. Training Manual.

    ERIC Educational Resources Information Center

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This document is a lecture/laboratory manual dealing with the analysis of selected inorganic pollutants. The manual is an instructional aid for classroom presentations to those with little or no experience in the field, but having one year (or equivalent) of college level inorganic chemistry and having basic laboratory skills. Topics include:…

  12. Reactions of inorganic nitrogen species in supercritical water

    SciTech Connect

    Dell`Orco, P.C.

    1994-12-31

    Redox reactions of nitrate salts with NH3 and methanol were studied in near-critical and supercritical water at 350 to 530 C and constant pressure of 302 bar. Sodium nitrate decomposition reactions were investigated at similar conditions. Reactions were conducted in isothermal tubular reactor under plug flow. For kinetic modeling, nitrate and nitrite reactants were lumped into an NO{sub x}{sup -} reactant; kinetic expressions were developed for MNO{sub 3}/NH{sub 4}X and sodium nitrate decomposition reactions. The proposed elementary reaction mechanism for MNO{sub 3}/NH{sub 4}X reaction indicated that NO{sub 2} was the primary oxidizing species and that N{sub 2}/N{sub 2}O selectivities could be determined by the form of MNO{sub 3} used. This suggest a nitrogen control strategy for use in SCWO (supercritical water oxidation) processes; nitrate or NH3 could be used to remove the other, at reaction conditions far less severe than required by other methods. Reactions of nitrate with methanol indicated that nitrate was a better oxidant than oxygen in supercritical water. Nitrogen reaction products included NH3 and nitrite, while inorganic carbon was the major carbon reaction product. Analysis of excess experiments indicated that the reaction at 475 C was first order in methanol concentration and second order in NO{sub x}{sup -} concentration. In order to determine phase regimes for these reactions, solubility of sodium nitrate was determined for some 1:1 nitrate electrolytes. Solubilities were measured at 450 to 525 C, from 248 to 302 bar. A semi-empirical solvation model was shown to adequately describe the experimental sodium nitrate solubilities. Solubilities of Li, Na, and K nitrates revealed with cations with smaller ionic radii had greater solubilities with nitrate.

  13. What's a Stream Without Water? Disproportionality in Headwater Regions Impacting Water Quality

    NASA Astrophysics Data System (ADS)

    Armstrong, Andrea; Stedman, Richard C.; Bishop, Joseph A.; Sullivan, Patrick J.

    2012-11-01

    Headwater streams are critical components of the stream network, yet landowner perceptions, attitudes, and property management behaviors surrounding these intermittent and ephemeral streams are not well understood. Our research uses the concept of watershed disproportionality, where coupled social-biophysical conditions bear a disproportionate responsibility for harmful water quality outcomes, to analyze the potential influence of riparian landowner perceptions and attitudes on water quality in headwater regions. We combine social science survey data, aerial imagery, and an analysis of spatial point processes to assess the relationship between riparian landowner perceptions and attitudes in relation to stream flow regularity. Stream flow regularity directly and positively shapes landowners' water quality concerns, and also positively influences landowners' attitudes of stream importance—a key determinant of water quality concern as identified in a path analysis. Similarly, riparian landowners who do not notice or perceive a stream on their property are likely located in headwater regions. Our findings indicate that landowners of headwater streams, which are critical areas for watershed-scale water quality, are less likely to manage for water quality than landowners with perennial streams in an obvious, natural channel. We discuss the relationships between streamflow and how landowners develop understandings of their stream, and relate this to the broader water quality implications of headwater stream mismanagement.

  14. Stream air temperature relations to classify stream ground water interactions in a karst setting, central Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Michael A.; DeWalle, David R.

    2006-09-01

    SummaryStream-ground water interactions in karst vary from complete losses through swallow holes, to reemergences from springs. Our study objective was to compare stream-air temperature and energy exchange relationships across various stream-ground water relationships in a carbonate watershed. It was hypothesized that ground water-fed stream segments could be distinguished from perched/losing segments using stream-air temperature relationships. Two types of computations were conducted: (1) comparisons of stream-air temperature relationships for the period of October 1999-September 2002 at 12 sites in the Spring Creek drainage and (2) detailed energy budget computations for the same period for ground water-dominated Thompson Run and Lower Buffalo Run, a stream with negligible ground water inputs. Weekly average air temperatures and stream temperatures were highly correlated, but slopes and intercepts of the relationship varied for the 12 sites. Slopes ranged from 0.19 to 0.67 and intercepts ranged from 3.23 to 9.07 °C. A two-component mixing model with end members of ground water and actual stream temperatures indicated that the slope and intercept of the stream-air temperature relationship was controlled by ground water inputs. Streams with large ground water inputs had greater intercepts and lesser slopes than streams that were seasonally losing, perched, and/or distant from ground water inputs. Energy fluxes across the air-water interface were greatest for the ground water-fed stream due to increased longwave, latent, and sensible heat losses from the stream in winter when large temperature and vapor pressure differences existed between the stream and air. Advection of ground water was an important source and sink for heat in the ground water-fed stream, depending on season. In contrast, along the seasonally losing stream reach, advection was of minimal importance and stream temperatures were dominated by energy exchange across the air- water interface. Overall

  15. Water table fluctuations near an incised stream, Walnut Creek, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Zhang, Y.-K.; Drobney, P.

    2004-01-01

    Incised channels are common features in many agricultural watersheds, but the effects of channel incision on riparian water table conditions have been poorly documented. In this study, we evaluate the water table fluctuations in the floodplain near an incised stream (Walnut Creek, Iowa) and investigate the roles that channel incision and variable recharge play in modifying the water table configuration in the floodplain. Groundwater flows from higher landscape positions towards Walnut Creek under hydraulic gradients that were steepest near the upland/floodplain contact and in the near-stream riparian zone. Annually, water table fluctuations on the floodplain were greatest in wells located 30 m from the creek, midway between the creek and upland. Water levels monitored continuously during a runoff event indicated that bank storage was confined to a narrow zone adjacent to the channel. A steady-state, one-dimensional analytical model was developed to describe the shape of the water table surface near an incised stream and evaluate how variable groundwater recharge and channel bed lowering has affected the shape of the water table surface. Results from this study have implications for managing the riparian buffers of incised streams with successful establishment dependent upon matching buffer vegetation to riparian water table conditions. ?? 2003 Elsevier B.V. All rights reserved.

  16. Trends in Catskill Stream Water Quality: Evidence From Historical Data

    NASA Astrophysics Data System (ADS)

    Stoddard, John L.

    1991-11-01

    Historical data for large streams in the Catskill Mountains indicate that acidic deposition has significantly influenced water quality, but that this effect is most observable in early (pre-1945) data, and consists primarily of increased base cation (CaMg) concentrations. More recent data suggest that landscape disturbance currently exerts a stronger influence on acid/base status of large streams than does acidic deposition, resulting in increases in both CaMg and acid-neutralizing capacity (ANC). Estimates of SO42- concentration indicate that SO42- is a conservative ion in the Catskills, and stream water concentrations have decreased since reaching maximum values around 1970, consistent with temporal trends in emissions and deposition in the northeastern United States. Nitrate concentrations, on the other hand, have increased substantially in all but one stream in the past two decades, independent of any change in nitrogen deposition in the region; changes in the capacity of watersheds to retain nitrogen are hypothesized as causes of increased stream water NO3-. In small, undisturbed streams, increases in NO3- and decreases in CaMg appear to offset the effects of reduced SO42-, and lead to decreasing trends in ANC.

  17. Geochemical results from stream-water and stream-sediment samples collected in Colorado and New Mexico

    USGS Publications Warehouse

    Hageman, Philip L.; Todd, Andrew S.; Smith, Kathleen S.; DeWitt, Ed; Zeigler, Mathew P.

    2013-01-01

    Scientists from the U.S. Geological Survey are studying the relationship between watershed lithology and stream-water chemistry. As part of this effort, 60 stream-water samples and 43 corresponding stream-sediment samples were collected in 2010 and 2011 from locations in Colorado and New Mexico. Sample sites were selected from small to midsize watersheds composed of a high percentage of one rock type or geologic unit. Stream-water and stream-sediment samples were collected, processed, preserved, and analyzed in a consistent manner. This report releases geochemical data for this phase of the study.

  18. Connections Among Terrestrial Sources of Organic and Inorganic Carbon and Surface Waters in a Permafrost- and Wildfire-Impacted Headwater Catchment, Alaska

    NASA Astrophysics Data System (ADS)

    Wickland, K.; Koch, J. C.; Crawford, J. T.; Dornblaser, M.; Kelsey, K.; Striegl, R. G.

    2014-12-01

    High-latitude headwater catchments commonly contain permafrost soils and are subject to disturbance by wildfire. Processes governing transport of organic and inorganic carbon from headwater catchments to surface waters, and the influence of permafrost and disturbance on those processes, remain poorly characterized. We conducted a two-year field study of a headwater catchment in interior Alaska to better understand terrestrial-aquatic linkages of carbon (C) in these systems. The 4.1 km2 catchment is underlain by permafrost, and is drained by a first-order stream. Portions of the catchment burned in 2003, resulting in localized removal of organic soils and subsequent permafrost thaw. During May - September of 2010 and 2011, we sampled stream and soil pore waters throughout the catchment on a weekly to bi-weekly basis for dissolved organic carbon (DOC), specific UV absorbance (SUVA), dissolved inorganic carbon (DIC), and dissolved carbon dioxide (CO2) and methane (CH4). Stream discharge and water chemistry were measured at two locations, reflecting drainage from the upper catchment (2.6 km2) and the entire catchment. Soil pore water sampling sites located between the two stream sampling stations included unburned hillslopes with permafrost depths ranging from 0.6 m to 0.75 m, burned hillslopes with permafrost depths to 1m, and riparian wetland with permafrost > 1m depth. Seasonal, interannual, and spatial differences in delivery of C constituents to the stream were evident over the two study years. Mean seasonal C loads and flow-weighted mean C concentrations (FWMC) for each stream reach showed that DOC and CH4 increased, and DIC and CO2 decreased in the downstream direction. Comparing stream FWMC to mean concentrations in soil pore waters, we determined that stream DOC, SUVA, and CH4 at the downstream location matched closely with values measured in the riparian wetland and burned hillslope locations, whereas DIC concentration was most similar to unburned hillslopes

  19. Dynamics of groundwater-surface water interactions in urban streams

    NASA Astrophysics Data System (ADS)

    Musolff, A.; Schmidt, C.; Fleckenstein, J. H.

    2010-12-01

    In industrialized countries the majority of streams and rivers have been subject to changes in the hydrological regime and alteration of the channel morphology. Urban streams are typically characterized by “flashier” hydrographs as a result of more direct runoff from impervious surfaces. Channel structure and complexity are often impaired compared to pristine streams. As a consequence the potential for bedform-driven water flow in the streambed is reduced. The downward transport of oxygen by advective flow in the streambed is known to be of great ecological importance for the hyporheic macro and micro fauna and facilitates nutrient cycling and the degradation of organic pollutants. We studied the dynamics of groundwater-surface water exchange of two anthropogenically impacted streams in urban areas to examine the effects of variable hydrologic boundary conditions on water flux and redox conditions in the streambed. The first stream is fed by groundwater as well as storm-water from a large industrial area. Here, we monitored the variability of vertical hydraulic gradients, streambed temperature and redox conditions in the streambed over the course of 5 months. The second stream is frequently polluted by combined sewer overflows (CSO) from an urban watershed. Here, we measured the vertical hydraulic gradients, streambed temperature and electrical conductivity (EC) in the stream, the streambed and in the adjacent aquifer. Both streams are characterized by strong variations in hydraulic gradients due to the dynamic hydrographs as well as the variations in total head in the shallow aquifer. Therefore, magnitude and direction of water flux through the streambed changed significantly over time. At the first site long-term variations of redox conditions in the shallow streambed (0.1 m) were related to the direction of water fluxes. Downward water flow resulted in increased redox potentials. However, the high short-term variability of redox conditions could not be

  20. Ground-water and stream-water interaction in the Owl Creek basin, Wyoming

    USGS Publications Warehouse

    Ogle, K.M.

    1996-01-01

    Understanding of the interaction of ground-water and surface-water resources is vital to water management when water availability is limited.Inflow of ground water is the primary source ofwater during stream base flow. The water chemistry of streams may substantially be affected by that inflow of ground water. This report is part of a study to examine ground-water and surface-water interaction in the Owl Creek Basin, Wyoming, completed by the U.S. Geological Survey incooperation with the Northern Arapaho Tribe and the Shoshone Tribe. During a low flow period between November\\x1113 - 17, 1991, streamflowmeasurements and water-quality samples were collected at 16 selected sites along major streams and tributaries in the Owl Creek Basin,Wyoming. The data were used to identify stream reaches receiving ground-water inflow and to examine causes of changes in stream chemistry.Streamflow measurements, radon-222 activity load, and dissolved solids load were used to identified stream reaches receiving ground-water inflow.Streamflow measurements identified three stream reaches receiving ground-water inflow. Analysis of radon-222 activity load identified five stream reaches receiving ground-water inflow. Dissolvedsolids load identified six stream reaches receiving ground-water inflow. When these three methods were combined, stream reaches in two areas, theEmbar Area and the Thermopolis Anticline Area, were identified as receiving ground-water inflow.The Embar Area and the Thermopolis Anticline Area were then evaluated to determine the source of increased chemical load in stream water. Three potential sources were analyzed: tributary inflow, surficial geology, and anticlines. Two sources,tributary inflow and surficial geology, were related to changes in isotopic ratios and chemical load in the Embar Area. In two reaches in the Embar Area, isotopic ratios of 18O/16O, D/H, and 34S/32S indicated that tributary inflow affected stream-water chemistry. Increased chemical load of

  1. Organic and Inorganic Matter in Louisiana Coastal Waters: Vermilion, Atchafalaya, Terrebonne, Barataria, and Mississippi Regions.

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) spectral absorption, dissolved organic carbon (DOC) concentration, and the particulate fraction of inorganic (PIM) and organic matter (POM) were measured in Louisiana coastal waters at Vermilion, Atchafalaya, Terrebonne, Barataria, and...

  2. Stream-Aquifer Exchange of Water and Nitrogen Along a Beaver-Dammed Stream Draining a Rocky Mountain Valley

    NASA Astrophysics Data System (ADS)

    Shaw, E. L.; Westbrook, C. J.

    2009-05-01

    Dynamic exchange of water across the stream-riparian zone interface is important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions that influence downstream water quality and ecosystem health. Such exchange may be enhanced by beaver dams, which are common throughout lower-order streams in North America and Europe. We investigated lateral exchanges of water and nitrogen along a beaver dammed, second-order stream draining a ˜1.3 km2 Canadian Rocky Mountain peat valley bottom. Measurements of hydraulic heads and chloride concentrations from a network of 80 water table wells were used to identify areas of stream water and groundwater mixing in the riparian zone, and their spatiotemporal dynamics in summer 2008. Stream stage was found to be the greatest factor affecting lateral movement of channel water into the riparian zone. Channel water flowed laterally into the riparian area upstream of the dams and back to the channel downstream of the dams. Little stream-aquifer exchange was found where dams were not present except during an overbank flood. Nitrate and DON concentrations were similar across the riparian area (P>0.05), regardless of whether the water was classified as groundwater, stream water or mixed water. In contrast, ammonium and DOC concentrations were significantly higher in the wells classified as groundwater or mixed water than those classified as stream water. Potential mass flux calculations show the riparian area immediately downstream of the beaver dam was a source of ammonium and nitrate to the stream, and a sink along the rest of the reach. DON shows similar trends with the exception of a net potential influx immediately upstream of the beaver dam. This work will aid in the understanding of stream-aquifer exchange and nitrogen cycling in riparian areas, and the effects that beaver have on these processes.

  3. Inorganic Analysis in Water Quality Control Programs. Instructor's Guide.

    ERIC Educational Resources Information Center

    Kroner, Audrey

    This two-part instructor's guide was designed for a five-day course for chemists and technicians with little or no experience in inorganic analyses. Part I provides information on course planning and management including course description, staff responsibilities, suggested course plan and agenda, timeline for planning and conducting the course,…

  4. The stream channel incision syndrome and water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Watershed development often triggers channel incision, which accounts for 60-90% of sediments leaving many disturbed watersheds. Impacts of such incision on water quality processes and the implication of such impairment on stream biota are relevant to issues associated with establishing total maxim...

  5. Sources of trends in water-quality data for selected streams in Texas, 1975-89 water years

    USGS Publications Warehouse

    Schertz, T.L.; Wells, F.C.; Ohe, D.J.

    1994-01-01

    Sources of trends in water-quality data for selected streams in Texas for the 1975-89 water years were investigated in this study. The investigation of sources was confined to distinct geographic patterns in the trend indicators for one constituent or for a group of related constituents. The probable source of trend patterns in nutrients and measures of oxygen in the Trinity River Basin was changes in the wastewater treatment facilities in the Dallas-Fort Worth metropolitan area. A pattern of increased concentrations of inorganic constituents in the upper Colorado River Basin resulted from emergency releases of water from the Natural Dam Lake, a salinity control structure. Trend patterns in inorganic constituents in the Rio Grande Basin were a result of increasing concentrations in the Pecos River and, to a lesser extent, the Rio Grande above the Amistad Reservoir, combined with the effects of reservoir regulation. A pattern of increasing concentrations of organic plus ammonia nitrogen and ammonia nitrogen was detected for the 1975-86 water years for stations with low concentrations (generally less than 5 milligrams per liter) of these nitrogen species. The trends were no longer evident when the period of trend analysis was extended to the 1989 water year. A positive bias in the data caused by the addition of mercuric chloride tablets to preserve nutrient samples during 1980-86 was the probable source of this trend pattern. A pattern of increasing concentrations in dissolved sulfate in the eastern part of the State was a result of a positive bias in the analytical results of a turbidimetric method of sulfate analysis. The source of a state-wide pattern of increased pH in streams could not be identified.

  6. Impacts of Labile Organic Carbon Concentration on Organic and Inorganic Nitrogen Utilization by a Stream Biofilm Bacterial Community

    PubMed Central

    Leff, Laura G.

    2013-01-01

    In aquatic ecosystems, carbon (C) availability strongly influences nitrogen (N) dynamics. One manifestation of this linkage is the importance in the dissolved organic matter (DOM) pool of dissolved organic nitrogen (DON), which can serve as both a C and an N source, yet our knowledge of how specific properties of DOM influence N dynamics are limited. To empirically examine the impact of labile DOM on the responses of bacteria to DON and dissolved inorganic nitrogen (DIN), bacterial abundance and community composition were examined in controlled laboratory microcosms subjected to various combinations of dissolved organic carbon (DOC), DON, and DIN treatments. Bacterial communities that had colonized glass beads incubated in a stream were treated with various glucose concentrations and combinations of inorganic and organic N (derived from algal exudate, bacterial protein, and humic matter). The results revealed a strong influence of C availability on bacterial utilization of DON and DIN, with preferential uptake of DON under low C concentrations. Bacterial DON uptake was affected by the concentration and by its chemical nature (labile versus recalcitrant). Labile organic N sources (algal exudate and bacterial protein) were utilized equally well as DIN as an N source, but this was not the case for the recalcitrant humic matter DON treatment. Clear differences in bacterial community composition among treatments were observed based on terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes. C, DIN, and DON treatments likely drove changes in bacterial community composition that in turn affected the rates of DON and DIN utilization under various C concentrations. PMID:24038688

  7. The Impact of Land Use Change on Primary Stream Organic and Inorganic Carbon Export

    NASA Astrophysics Data System (ADS)

    Kelsey, S. A.; Bauer, J. E.; Grottoli, A. G.; Huey Sanders, T. M.; Matsui, Y.

    2015-12-01

    Terrestrial land use may impact both the amounts of and characteristics of organic and inorganic carbon (OC and IC, respectively) entering aquatic ecosystems. Better understanding of how different land uses alter carbon characteristics and export fluxes from watersheds may lead to better management practices for retaining OC in terrestrial habitats and therefore mitigate CO2 emissions from freshwater ecosystems where terrestrial OC may be more rapidly respired. We examined the fluxes and δ13C and ∆14C signatures of dissolved IC (DIC), dissolved OC (DOC), and particulate OC (POC) exported from 6 watersheds with differing land use at the North Appalachian Experimental Watershed (NAEW) in Coshocton county in northeastern Ohio to assess whether differences in land use are related to variability in the export fluxes and isotopic characteristics of OC and IC pools. We used a Bayesian mixing model (MixSIR) to determine how the relative contributions of potential carbon sources to DIC, DOC, and POC change as a function of watershed land use. Mixing model results from each season were used to approximate relative annual contributions of potential sources to DIC, DOC, and POC export fluxes from each watershed. We found that agricultural land uses (i.e., corn, under both conventional till and no-till management) experienced the greatest degree of disturbance and had the greatest carbon export fluxes. However, the relative extent to which soil OC contributed to export fluxes compared to corn biomass varied as a function of tillage practices. In addition, nonparametric multidimensional scaling (NMDS), based on the δ13C and ∆14C data and mixing model results for DIC, DOC and POC export fluxes, separated non-corn watersheds into 2 further classes of disturbance: moderate disturbance (pasture and mixed land use) and low disturbance (forest). These findings suggest that land use has a measurable impact on the concentration and characteristics of watershed C export fluxes.

  8. What causes cooling water temperature gradients in forested stream reaches?

    NASA Astrophysics Data System (ADS)

    Garner, G.; Malcolm, I. A.; Sadler, J. P.; Hannah, D. M.

    2014-06-01

    Previous studies have suggested that shading by riparian vegetation may reduce maximum water temperature and provide refugia for temperature sensitive aquatic organisms. Longitudinal cooling gradients have been observed during the daytime for stream reaches shaded by coniferous trees downstream of clear cuts, or deciduous woodland downstream of open moorland. However, little is known about the energy exchange processes that drive such gradients, especially in semi-natural woodland contexts, and in the absence of potentially confounding cool groundwater inflows. To address this gap, this study quantified and modelled variability in stream temperature and heat fluxes along an upland reach of the Girnock Burn (a tributary of the Aberdeenshire Dee, Scotland) where riparian landuse transitions from open moorland to semi-natural forest. Observations were made along a 1050 m reach using a spatially-distributed network of ten water temperature micro-loggers, three automatic weather stations and >200 hemispherical photographs, which were used to estimate incoming solar radiation. These data parameterised a high-resolution energy flux model, incorporating flow-routing, which predicted spatio-temporal variability in stream temperature. Variability in stream temperature was controlled largely by energy fluxes at the water column-atmosphere interface. Predominantly net energy gains occurred along the reach during daylight hours, and heat exchange across the bed-water column interface accounted for <1% of the net energy budget. For periods when daytime net radiation gains were high (under clear skies), differences between water temperature observations decreased in the streamwise direction; a maximum difference of 2.5 °C was observed between the upstream reach boundary and 1050 m downstream. Furthermore, daily maximum water temperature at 1050 m downstream was ≤1°C cooler than at the upstream reach boundary and lagged the occurrence of daily maximum water temperature

  9. Multiscale Drivers of Water Chemistry of Boreal Lakes and Streams

    PubMed Central

    Johnson, Richard K.

    2006-01-01

    The variability in surface water chemistry within and between aquatic ecosystems is regulated by many factors operating at several spatial and temporal scales. The importance of geographic, regional-, and local-scale factors as drivers of the natural variability of three water chemistry variables representing buffering capacity and the importance of weathering (acid neutralizing capacity, ANC), nutrient concentration (total phosphorus, TP), and importance of allochthonous inputs (total organic carbon, TOC) were studied in boreal streams and lakes using a method of variance decomposition. Partial redundancy analysis (pRDA) of ANC, TP, and TOC and 38 environmental variables in 361 lakes and 390 streams showed the importance of the interaction between geographic position and regional-scale variables. Geographic position and regional-scale factors combined explained 15.3% (streams) and 10.6% (lakes) of the variation in ANC, TP, and TOC. The unique variance explained by geographic, regional, and local-scale variables alone was <10%. The largest amount of variance was explained by the pure effect of regional-scale variables (9.9% for streams and 7.8% for lakes), followed by local-scale variables (2.9% and 5.8%) and geographic position (1.8% and 3.7%). The combined effect of geographic position, regional-, and local-scale variables accounted for between 30.3% (lakes) and 39.9% (streams) of the variance in surface water chemistry. These findings lend support to the conjecture that lakes and streams are intimately linked to their catchments and have important implications regarding conservation and restoration (management) endeavors. PMID:16955233

  10. EFFECTS OF STREAM RESTORATION ON GROUND WATER NITRATE AT MINEBANK RUN, AN URBAN STREAM IN THE CHESAPEAKE BAY WATERSHED

    EPA Science Inventory

    Elevated nitrate levels in streams and ground water pose human and ecological threats. Microbial denitrification removes nitrate from ground water but requires anaerobic (saturated) conditions and adequate supply of dissolved organic carbon from detritus and organic soils. Con...

  11. Linking Nitrate Uptake and Water Storage in an Antarctic Stream

    NASA Astrophysics Data System (ADS)

    Koch, J. C.; McKnight, D. M.; Baeseman, J.

    2007-12-01

    A nitrate enrichment experiment was performed in Huey Creek, a glacial meltwater stream in the McMurdo Dry Valleys of Antarctica, to determine processes responsible for nitrate loss in a polar desert stream with no visible vegetation. Streamflow in Huey follows a diel cycle, resulting in temporal and spatial variability in two separate storage areas - a near-stream and far-lateral hyporheic zone. Near-stream hyporheic exchange occurred in only one of four monitored stream reaches, with a mean uptake rate of 0.042 umol N/m2/hr. Uptake rates could not be balanced by nitrite, ammonium, and nitrous oxide production, suggesting the importance of biomass as a source and sink of nitrogen. During high flows, nitrate loss is accompanied by a pulse of ammonium that accounts for an average of 42% of the total nitrate loss. Ammonium production is 4.4 times greater than nitrate loss during one hour of the flood, providing further evidence that nitrogen has been stored in the subsurface biomass, and is mineralized as a result of the fresh water penetrating the hyporheic zone. Properties of the far-lateral hyporheic zone were also flow-dependent. Exchange from stream to subsurface occurred during floods, when anabranches moved water laterally across the channel banks. Exchange back to the stream occurred with the recession of flood stage. Pulses of nitrate species downstream of this storage zone suggest significant denitrification in this far-lateral hyporheic zone. The first flood recession plume consisted mainly of nitrite, while the second was dominated by ammonium, suggesting a greater amount of denitrification in the second pulse. Both pulses were accompanied by high quantities of DOC (121 and 287% of mean background mass, respectively) - an unexpected result in this carbon-limited system. These results highlight the linkage between water and desert ecosystems, and challenge researchers to understand both spatial and temporal variability in potential ecological hotspots and

  12. An evaluation of water-quality records for Texas streams

    USGS Publications Warehouse

    Blakey, J.F.; Hawkinson, R.O.; Steele, T.D.

    1972-01-01

    Chemical data for 12 streamflow-sampling stations in Texas, each having from 8 to 24 years of available historical records, were analyzed to determine functional relationships between concentrations of the major inorganic constituents and specific conductance or stream discharge. Regression equations for each station were derived by using data for an identical 5-year period; the remaining record served as independent test data for checking the adequacy of the functions on the basis of continued specific-conductance determinations as an index variable. Daily solute concentrations and loads at a sampling site were simulated, and monthly and annual averages were computed by using daily records of specific conductance in conjunction with the regression equations. Simulated annual mean concentrations of most individual solutes and dissolved solids averaged within 10-20 percent of comparable concentrations determined from the composited chemical analyses, although systematic biases were detected in results for some of the relationships used in the simulation. Results of the evaluation of the 12 stations indicated that regression equations, using specific conductance as the independent variable, can be used as an alternative to composite analyses for calculation of solute concentrations and loads in Texas streams and is a flexible system that can be applied with sufficient accuracy to satisfy most anticipated needs for data.

  13. Streaming Potential In Rocks Saturated With Water And Oil

    NASA Astrophysics Data System (ADS)

    Tarvin, J. A.; Caston, A.

    2011-12-01

    Fluids flowing through porous media generate electrical currents. These currents cause electric potentials, called "streaming potentials." Streaming potential amplitude depends on the applied pressure gradient, on rock and fluid properties, and on the interaction between rock and fluid. Streaming potential has been measured for rocks saturated with water (1) and with water-gas mixtures. (2) Few measurements (3) have been reported for rocks saturated with water-oil mixtures. We measured streaming potential for sandstone and limestone saturated with a mixture of brine and laboratory oil. Cylindrical samples were initially saturated with brine and submerged in oil. Saturation was changed by pumping oil from one end of a sample to the other and then through the sample in the opposite direction. Saturation was estimated from sample resistivity. The final saturation of each sample was determined by heating the sample in a closed container and measuring the pressure. Measurements were made by modulating the pressure difference (of oil) between the ends of a sample at multiple frequencies below 20 Hz. The observed streaming potential is a weak function of the saturation. Since sample conductivity decreases with increasing oil saturation, the electro-kinetic coupling coefficient (Pride's L (4)) decreases with increasing oil saturation. (1) David B. Pengra and Po-zen Wong, Colloids and Surfaces, vol., p. 159 283-292 (1999). (2) Eve S. Sprunt, Tony B. Mercer, and Nizar F. Djabbarah, Geophysics, vol. 59, p. 707-711 (1994). (3) Vinogradov, J., Jackson, M.D., Geophysical Res. L., Vol. 38, Article L01301 (2011). (4) Steve Pride, Phys. Rev. B, vol. 50, pp. 15678-15696 (1994).

  14. Fragmentation and quench behavior of corium melt streams in water

    SciTech Connect

    Spencer, B.W.; Wang, K.; Blomquist, C.A.; McUmber, L.M.; Schneider, J.P.

    1994-02-01

    The interaction of molten core materials with water has been investigated for the pour stream mixing mode. This interaction plays a crucial role during the later stages of in-vessel core melt progression inside a light water reactor such as during the TMI-2 accident. The key issues which arise during the molten core relocation include: (i) the thermal attack and possible damage to the RPV lower head from the impinging molten fuel stream and/or the debris bed, (ii) the molten fuel relocation pathways including the effects of redistribution due to core support structure and the reactor lower internals, (iii) the quench rate of the molten fuel through the water in the lower plenum, (iv) the steam generation and hydrogen generation during the interaction, (v) the transient pressurization of the primary system, and (vi) the possibility of a steam explosion. In order to understand these issues, a series of six experiments (designated CCM-1 through {minus}6) was performed in which molten corium passed through a deep pool of water in a long, slender pour stream mode. Results discussed include the transient temperatures and pressures, the rate and magnitude of steam/hydrogen generation, and the posttest debris characteristics.

  15. Dry Valley streams in Antarctica: Ecosystems waiting for water

    USGS Publications Warehouse

    McKnight, Diane M.; Niyogi, D.K.; Alger, A.S.; Bomblies, A.; Conovitz, P.A.; Tate, C.M.

    1999-01-01

    An axiom of ecology is: 'Where there is water, there is life.' In dry valley ecosystems of Antarctica, this axiom can be extended to: 'Where there has been and will be water, there is life.' Stream communities in the dry valleys can withstand desiccation on an annual basis and also for longer periods - as much as decades or even centuries. These intact ecosystems, consisting primarily of cyanobacteria and eukaryotic algae, spring back to life with the return of water. Soil organisms in the dry valleys also have remarkable survival capabilities (Virginia and Wall 1999), emerging from dormancy with the arrival of water. Streams in the dry valleys carry meltwater from a glacier or ice-field source to the lakes on the valley floors and generally flow for 4-10 weeks during the summer, depending on climatic conditions. Many of these streams contain abundant algal mats that are perennial in the sense that they are in a freeze-dried state during the winter and begin growing again within minutes of becoming wetted by the first flow of the season. The algal species present in the streams are mainly filamentous cyanobacteria (approximately 20 species of the genera Phormidium, Oscillatoria, and Nostoc), two green algal species of the genus Prasiola, and numerous diatom taxa that are characteristic of soil habitats and polar regions. Algal abundances are greatest in those streams in which periglacial processes, acting over periods of perhaps a century, have produced a stable stone pavement in the streambed. This habitat results in a less turbulent flow regime and limits sediment scour from the streambed. Because dry valley glaciers advance and retreat over periods of centuries and millennia and stream networks in the dry valleys evolve through sediment deposition and transport, some of the currently inactive stream channels may receive flow again in the future. Insights- into the process of algal persistence and reactivation will come from long-term experiments that study the

  16. Experimental studies of aluminum mobility in organic rich riparian soil and stream water in Sweden

    NASA Astrophysics Data System (ADS)

    Wonisch, H.; Cory, N.; Buffam, I.; Laudon, H.; Bishop, K.; Dietzel, M.; Köhler, S. J.

    2009-04-01

    The role of organic acids in mobilizing and controlling aluminum (Al) from a riparian soil profile into a small humic-rich stream draining a forested catchment area was studied in Northern Sweden. Three in-situ soil and stream water manipulation experiments were performed by changing total concentrations of Al and silica while keeping pH constant between 4.8 and 5.6 to decipher the processes regulating stream Al solubility and export. Removal of added silica could not be observed along the 80 m stream reach during the stream manipulation despite a saturation index for Proto-Imogolite higher than 2.5. Removal of dissolved Al and DOC in the stream and the superficial soil solutions of the unsaturated zone occurred at molar Al/DOC ratios above 0.13±0.01. For the lower soil horizons that are in permanent contact with groundwater (45-65 cm) and supply the stream with water during the largest part of the year a ratio above 0.073±0.01 was sufficient to induce Al removal. In all experiments (lab and field) an apparent ion activity product (IAP) for Al(OH)3 of 10.5±0.5 was necessary to induce Al removal. This IAP is rarely reached in the soil solutions or the adjacent stream despite large temporal fluctuations of both TOC and pH during the last 10 years. Al/TOC ratios in both environments are independent of pH and have a constant Al/TOC ratio with minimal variation; 0.013±0.002 (n=61) for the stream and 0.037±0.010 (n=135) for the riparian soil waters within the catchment. The similarities in the riparian soil depth profiles for BaCl2 exchangeable Al and TOC concentrations indicate that the soil organic exchanger complex may explain the small variability of the Al/TOC ratio in the soil. The loss of Al from the soil water during the transport through the riparian zone into the stream might be controlled by organic matter and not an inorganic Al bearing phase. However, to decipher the exact mechanism for the fixation of more than 70% of the soil solution Al in the

  17. Optimal placement of off-stream water sources for ephemeral stream recovery

    USGS Publications Warehouse

    Rigge, Matthew B.; Smart, Alexander; Wylie, Bruce

    2013-01-01

    Uneven and/or inefficient livestock distribution is often a product of an inadequate number and distribution of watering points. Placement of off-stream water practices (OSWP) in pastures is a key consideration in rangeland management plans and is critical to achieving riparian recovery by improving grazing evenness, while improving livestock performance. Effective OSWP placement also minimizes the impacts of livestock use radiating from OSWP, known as the “piosphere.” The objective of this study was to provide land managers with recommendations for the optimum placement of OSWP. Specifically, we aimed to provide minimum offset distances of OSWP to streams and assess the effective range of OSWP using Normalized Difference Vegetation Index (NDVI) values, an indicator of live standing crop. NDVI values were determined from a time-series of Satellite Pour l'Observation de la Terre (SPOT) 20-m images of western South Dakota mixed-grass prairie. The NDVI values in ephemeral stream channels (in-channel) and uplands were extracted from pre- and post-OSWP images taken in 1989 and 2010, respectively. NDVI values were normalized to a reference imagine and subsequently by ecological site to produce nNDVI. Our results demonstrate a significant (P 2 = 0.49, P = 0.05) and increased with average distance to OSWP in a pasture (R2 = 0.43, P = 0.07). Piospheric reduction in nNDVI was observed within 200 m of OSWP, occasionally overlapping in-channel areas. The findings of this study suggest placement of OSWP 200 to 1 250 m from streams to achieve optimal results. These results can be used to increase grazing efficiency by effectively placing OSWP and insure that piospheres do not overlap ecologically important in-channel areas.

  18. Dissolved inorganic nitrogen composition, transformation, retention, and transport in naturally phosphate-rich and phosphate-poor tropical streams

    USGS Publications Warehouse

    Triska, F.J.; Pringle, C.M.; Zellweger, G.W.; Duff, J.H.; Avanzino, R.J.

    1993-01-01

    In Costa Rica, the Salto River is enriched by geothermal-based soluble reactive phosphorus (SRP), which raises the concentration up to 200 ??g/L whereas Pantano Creek, an unimpacted tributary, has an SRP concentration <10 ??g/L. Ammonium concentration in springs adjacent to the Salto and Pantano was typically greater than channel water (13 of 22 locations) whereas nitrate concentration was less (20 of 22 locations). Ground waters were typically high in ammonium relative to nitrate whereas channel waters were high in nitrate relative to ammonium. Sediment slurry studies indicated nitrification potential in two sediment types, firm clay (3.34 ??g N.cm-3.d-1) and uncompacted organic-rich sediment (1.76 ??g N.cm-3.d-1). Ammonium and nitrate amendments to each stream separately resulted in nitrate concentrations in excess of that expected after correlation for dilution using a conservative tracer. SRP concentration was not affected by DIN amendment to either stream. SRP concentration in the Pantano appeared to be regulated by abiotic sediment exchange reactions. DIN composition and concentration were regulated by a combination of biotic and abiotic processes. -from Authors

  19. Water's Journey from Rain to Stream in perspective

    NASA Astrophysics Data System (ADS)

    Rodhe, Allan; Grip, Harald

    2015-04-01

    The International Hydrological Decade (IHD) 1965-1974, sponsored by UNESCO, initiated a research effort for coordinating the fragmented branches of hydrology and for understanding and quantifying the hydrologic cycle on various scales, from continents to small catchments. One important part of the Swedish IHD-program was to quantify the terms of the water budget, including detailed data on soil water and groundwater storage dynamics, of several medium sized to small. As an outcome of these studies and subsequent process oriented studies, a new view of the runoff process in forested till soils was developed in the 1970's, stressing the dominating role of groundwater in delivering water to the streams and the usefulness of subdividing catchments into recharge and discharge areas for groundwater for understanding the flowpaths of water. This view contrasted with the general view among the public, and also among professionals within the field and in text books, according to which overland flow is the main process for runoff. With this latter view it would, for instance, not be possible to understand stream water chemistry, which had become an important question in a time of growing environmental concern. In order to decrease the time lag between research results and practice, the Swedish Natural Science Research Council initiated a text book project for presenting the recent results of hydrologic research on stream flow generation applied to Swedish conditions, and in 1985 our book "Water's Journey from Rain to Stream" was published. Founded on the basic principles for water storage and flow in soils, the book gives a general picture of the water flow through the forested till landscape, with separate chapters for recharge and discharge areas. Chemical processes along the flowpaths of water are treated and the book concludes with a few applications to current issues. The book is written in Swedish and the target audience is those working professionally with water and

  20. Nitrogen dynamics at the groundwater-surface water interface of a degraded urban stream (journal)

    EPA Science Inventory

    Urbanization degrades stream ecosystems by altering hydrology and nutrient dynamics, yet relatively little effort has been devoted to understanding biogeochemistry of urban streams at the ground water-surface water interface. This zone may be especially important for nitrogen re...

  1. Potential Impacts of Organic Wastes on Small Stream Water Quality

    NASA Astrophysics Data System (ADS)

    Kaushal, S. S.; Groffman, P. M.; Findlay, S. E.; Fischer, D. T.; Burke, R. A.; Molinero, J.

    2005-05-01

    We monitored concentrations of dissolved organic carbon (DOC), dissolved oxygen (DO) and other parameters in 17 small streams of the South Fork Broad River (SFBR) watershed on a monthly basis for 15 months. The subwatersheds were chosen to reflect a range of land uses including forested, pasture, mixed, and developed. The SFBR watershed is heavily impacted by organic wastes, primarily from its large poultry industry, but also from its rapidly growing human population. The poultry litter is primarily disposed of by application to pastures. Our monthly monitoring results showed a strong inverse relationship between mean DOC and mean DO and suggested that concentrations of total nitrogen (TN), DOC, and the trace gases nitrous oxide, methane and carbon dioxide are impacted by organic wastes and/or nutrients from animal manure applied to the land and/or human wastes from wastewater treatment plants or septic tanks in these watersheds. Here we estimate the organic waste loads of these watersheds and evaluate the impact of organic wastes on stream DOC and alkalinity concentrations, electrical conductivity, sediment potential denitrification rate and plant stable nitrogen isotope ratios. All of these water quality parameters are significantly correlated with watershed waste loading. DOC is most strongly correlated with total watershed waste loading whereas conductivity, alkalinity, potential denitrification rate and plant stable nitrogen isotope ratio are most strongly correlated with watershed human waste loading. These results suggest that more direct inputs (e.g., wastewater treatment plant effluents, near-stream septic tanks) have a greater relative impact on stream water quality than more dispersed inputs (land applied poultry litter, septic tanks far from streams) in the SFBR watershed. Conductivity, which is generally elevated in organic wastes, is also significantly correlated with total watershed waste loading suggesting it may be a useful indicator of overall

  2. SPECIATION AND PRESERVATION OF INORGANIC ARSENIC IN DRINKING WATER SUPPLIES WITH IC-ICP-MS

    EPA Science Inventory

    The speciation of inorganic arsenic in drinking water supplies is an essential part of devising an appropriate treatment process. Arsenate, because of its anion characteristics at drinking water pHs, is effectively removed by anion exchange treatment while arsenite remains in the...

  3. System Regulates the Water Contents of Fuel-Cell Streams

    NASA Technical Reports Server (NTRS)

    Vasquez, Arturo; Lazaroff, Scott

    2005-01-01

    An assembly of devices provides for both humidification of the reactant gas streams of a fuel cell and removal of the product water (the water generated by operation of the fuel cell). The assembly includes externally-sensing forward-pressure regulators that supply reactant gases (fuel and oxygen) at variable pressures to ejector reactant pumps. The ejector supply pressures depend on the consumption flows. The ejectors develop differential pressures approximately proportional to the consumption flow rates at constant system pressure and with constant flow restriction between the mixer-outlet and suction ports of the ejectors. For removal of product water from the circulating oxygen stream, the assembly includes a water/gas separator that contains hydrophobic and hydrophilic membranes. The water separator imposes an approximately constant flow restriction, regardless of the quality of the two-phase flow that enters it from the fuel cell. The gas leaving the water separator is nearly 100 percent humid. This gas is returned to the inlet of the fuel cell along with a quantity of dry incoming oxygen, via the oxygen ejector, thereby providing some humidification.

  4. Water recovery from saline streams produced by electrodialysis.

    PubMed

    Andrade Becheleni, Emily Mayer; Borba, Ricardo Perobelli; Seckler, Marcelo Martins; Ferreira Rocha, Sônia Denise

    2015-01-01

    Advances in technologies to enable water reuse in industry have been the objective of many research efforts, mainly due to the need to reduce the use of natural resources and due to factors related to their availability. This paper evaluates the crystallization of salts from petrochemical saline waste to achieve zero water discharge by the recovery of water and dissolved salts as a solid mixture. In line with process symbiosis, the recovered water should be suitable for use as cooling water in heat exchangers. Vacuum evaporative crystallization, at the batch scale, was used to remove the salts present in the concentrated stream from reverse electrodialysis of pretreated wastewater by a biological process. The partition of organic compounds in the feed solution between the condensate and the mother liquor was obtained from measurements of the total organic carbon and total nitrogen in the solutions. The solid phases formed experimentally are compared with those predicted by chemical modelling by PHREEQC. The recovered water presented almost 50 times less total dissolved solids than the feed stream (from 2100 to 44 mg/L). Calcium sulphate hydrate, calcium sulphate and sodium chloride were the majority crystalline phases formed, in accordance with the modelling by PHREEQC. PMID:25338133

  5. Characterizing changing stream water quality in a glacierized tropical watershed

    NASA Astrophysics Data System (ADS)

    Mark, B. G.; Eddy, A. M.; Baraer, M.; McKenzie, J. M.; Walsh, E.; Fernandez, A.; Wigmore, O.; Battista, R.; Guittard, A.

    2013-12-01

    Glacier recession in the Cordillera Blanca, Peru has been causing downstream hydrologic transformations, altering the amount, timing and chemical quality of stream water. Increased demand from multiple water resource users, particularly industrial-scale agricultural irrigation along the desert coast, underscores the need for accurate source attribution and treatment of pollutants. Water quality assessment is challenging given natural geologic controls on water chemistry concentrations, and a lack of consistent historical monitoring. Here we present results from an analytical characterization of spatial and temporal variability in the dissolved loads of major ions, isotopes and select trace metals in the Pacific-draining Santa River and tributaries. Our approach incorporates multi-year synoptic sampling of water chemistry and stream discharge along the river course and at tributary pour points, along with weekly sampling at single point along the upper Santa. Samples were taken predominately during the austral winter months of June, July, and August in 2004 - 2009 and 2011 - 2013 at 20-30 stream localities. Digitized maps of geology, land use and hydrography permit geographic visualization and exploratory GIS-based data analysis. Results indicate that the dominant hydrochemical processes throughout the Santa watershed include silicate weathering, coupled pyrite oxidation with silicate weathering, and to a lesser extent, carbonate weathering. Low pH and high concentrations of sulfate are found in the presence of high-silica granitic and metamorphic surface lithology in some sites proximal to receding glaciers, reflecting an environment that is driven by coupled sulfide-oxidation and silicate dissolution. Numerous sites had elevated concentrations of trace metals (such as As, Cd, and Pb) indicating potential local sources of contamination, some in excess of World Health Organization. Weekly sampling show dilution of certain trace metals during the wet season, and

  6. The effect of water exchange on bacterioplankton depletion and inorganic nutrient dynamics in coral reef cavities

    NASA Astrophysics Data System (ADS)

    van Duyl, F. C.; Scheffers, S. R.; Thomas, F. I. M.; Driscoll, M.

    2006-03-01

    We studied the effect of water exchange on the depletion (or accumulation) of bacterioplankton, dissolved organic matter and inorganic nutrients in small open framework cavities (50-70 l) at 15 m depth on the coral reef along Curaçao, Netherlands Antilles. The bacterioplankton removal rate in cavities increased with increasing water exchange rates up to a threshold of 0.0045 s-1, reaching values of 50-100 mg C m-2 total interior cavity surface area (CSA) per day. Beyond the threshold, bacterioplankton removal dropped. The cryptic community is apparently adapted to the average water exchange in these cavities (0.0041 s-1). Dissolved inorganic nitrogen (DIN), nitrate + nitrite (NO x ) in particular, accumulated in cavity water and the accumulation decreased with increasing water exchange. Net NO x effluxes exceeded net DIN effluxes from cavities (average efflux rate of 1.9 mmol NO x vs. 0.8 mmol DIN m-2 interior CSA per day). The difference is ascribed to net ammonium losses (NH4) in cavities at reef concentrations >0.025 μM NH4, possibly due to enhanced nitrification. Dissolved inorganic phosphate accumulated in cavities, but was not related to water exchange. The cryptic biota in cavities depend on water exchange for optimization of consumption of bacterioplankton and removal of inorganic nitrogen. Coral cavities are an evident sink of bacterioplankton and a source of NO x and PO{4/3-}.

  7. Removal of Dental Biofilms with an Ultrasonically Activated Water Stream.

    PubMed

    Howlin, R P; Fabbri, S; Offin, D G; Symonds, N; Kiang, K S; Knee, R J; Yoganantham, D C; Webb, J S; Birkin, P R; Leighton, T G; Stoodley, P

    2015-09-01

    Acidogenic bacteria within dental plaque biofilms are the causative agents of caries. Consequently, maintenance of a healthy oral environment with efficient biofilm removal strategies is important to limit caries, as well as halt progression to gingivitis and periodontitis. Recently, a novel cleaning device has been described using an ultrasonically activated stream (UAS) to generate a cavitation cloud of bubbles in a freely flowing water stream that has demonstrated the capacity to be effective at biofilm removal. In this study, UAS was evaluated for its ability to remove biofilms of the cariogenic pathogen Streptococcus mutans UA159, as well as Actinomyces naeslundii ATCC 12104 and Streptococcus oralis ATCC 9811, grown on machine-etched glass slides to generate a reproducible complex surface and artificial teeth from a typodont training model. Biofilm removal was assessed both visually and microscopically using high-speed videography, confocal scanning laser microscopy (CSLM), and scanning electron microscopy (SEM). Analysis by CSLM demonstrated a statistically significant 99.9% removal of S. mutans biofilms exposed to the UAS for 10 s, relative to both untreated control biofilms and biofilms exposed to the water stream alone without ultrasonic activation (P < 0.05). The water stream alone showed no statistically significant difference in removal compared with the untreated control (P = 0.24). High-speed videography demonstrated a rapid rate (151 mm(2) in 1 s) of biofilm removal. The UAS was also highly effective at S. mutans, A. naeslundii, and S. oralis biofilm removal from machine-etched glass and S. mutans from typodont surfaces with complex topography. Consequently, UAS technology represents a potentially effective method for biofilm removal and improved oral hygiene. PMID:26056055

  8. Sensitivity of stream water age to climatic variability and land use change: implications for water quality

    NASA Astrophysics Data System (ADS)

    Soulsby, Chris; Birkel, Christian; Geris, Josie; Tetzlaff, Doerthe

    2016-04-01

    Advances in the use of hydrological tracers and their integration into rainfall runoff models is facilitating improved quantification of stream water age distributions. This is of fundamental importance to understanding water quality dynamics over both short- and long-time scales, particularly as water quality parameters are often associated with water sources of markedly different ages. For example, legacy nitrate pollution may reflect deeper waters that have resided in catchments for decades, whilst more dynamics parameters from anthropogenic sources (e.g. P, pathogens etc) are mobilised by very young (<1 day) near-surface water sources. It is increasingly recognised that water age distributions of stream water is non-stationary in both the short (i.e. event dynamics) and longer-term (i.e. in relation to hydroclimatic variability). This provides a crucial context for interpreting water quality time series. Here, we will use longer-term (>5 year), high resolution (daily) isotope time series in modelling studies for different catchments to show how variable stream water age distributions can be a result of hydroclimatic variability and the implications for understanding water quality. We will also use examples from catchments undergoing rapid urbanisation, how the resulting age distributions of stream water change in a predictable way as a result of modified flow paths. The implication for the management of water quality in urban catchments will be discussed.

  9. Trends in Stream Water Quality in the Southeastern United States

    NASA Astrophysics Data System (ADS)

    Harned, D. A.; Staub, E. L.; Peak, K. L.

    2007-12-01

    As part of the U.S Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program water-quality data for 253 streams in 8 states of the Southeastern United States were assessed for trends from 1973-2005. Forty-three USGS sampling sites were examined for trends over multiple periods within 1973-2005 in measures of pH, specific conductance, and dissolved oxygen; and in concentrations of dissolved solids, suspended sediment, chloride, sodium, sulfate, silica, potassium, carbon, total nitrogen, total ammonia, total ammonia plus organic nitrogen, dissolved nitrite plus nitrate, and total phosphorus. An additional 210 sites from the U.S. Environmental Protection Agency STORET database were tested for trends in total nitrogen and total phosphorus concentrations over the 1975-2004 and 1993-2004 periods. The seasonal Kendall test or Tobit regression was used to detect monotonic trends. Concentrations of dissolved constituents have increased in many streams in the Southeast over the last 30 years. Specific conductance, an indicator of dissolved ions in water, increased in the Southeast in 26 USGS sites over the long term, but showed fewer increases in the 1993-2004 period. The pH increased at 11 of the 43 USGS sites in the Southeast from 1975 to 1985. Fewer trends in pH are apparent for 1993-2004. Concentrations of phosphorus in streams in the Southeast have decreased over the last 35 years coinciding with phosphate detergent bans and improvements in waste-water treatment that were implemented beginning in 1972. Sixteen of the 17 long-term trends in phosphorus concentrations detected at the 43 USGS sites were decreasing. Twenty-seven of the 32 long-term (1975-2004) trends detected in total phosphorus concentrations at the 210 STORET sites were decreasing. Nitrogen trends the Southeast are mixed. Decreasing trends in total nitrogen observed at USGS sites from 1975 to 1995 are not apparent during 1993-2004. Of the 18 recent (1993-2004) trends in total nitrogen

  10. Temporal dynamics of groundwater-dissolved inorganic carbon beneath a drought-affected braided stream: Platte River case study

    NASA Astrophysics Data System (ADS)

    Boerner, Audrey R.; Gates, John B.

    2015-05-01

    Impacts of environmental changes on groundwater carbon cycling are poorly understood despite their potentially high relevance to terrestrial carbon budgets. This study focuses on streambed groundwater chemistry during a period of drought-induced river drying and consequent disconnection between surface water and groundwater. Shallow groundwater underlying vegetated and bare portions of a braided streambed in the Platte River (Nebraska, USA) was monitored during drought conditions in summer 2012. Water temperature and dissolved inorganic carbon (dominated by HCO3-) in streambed groundwater were correlated over a 3 month period coinciding with a decline in river discharge from 35 to 0 m3 s-1. Physical, chemical, and isotopic parameters were monitored to investigate mechanisms affecting the HCO3- trend. Equilibrium thermodynamic modeling suggests that an increase of pCO2 near the water table, coupled with carbonate mineral weathering, can explain the trend. Stronger temporal trends in Ca2+ and Mg2+ compared to Cl- are consistent with carbonate mineral reequilibria rather than evaporative concentration as the primary mechanism of the increased HCO3-. Stable isotope trends are not apparent, providing further evidence of thermodynamic controls rather than evaporation from the water table. A combination of increased temperature and O2 in the dewatered portion of the streambed is the most likely driver of increased pCO2 near the water table. Results of this study highlight potential linkages between surface environmental changes and groundwater chemistry and underscore the need for high-resolution chemical monitoring of alluvial groundwater in order to identify environmental change impacts.

  11. Organic and Inorganic Species in CBM Produced Water: Implications for Water Management Strategies

    NASA Astrophysics Data System (ADS)

    Kharaka, Y. K.; Rice, C. A.

    2003-12-01

    Coal-bed methane (CBM) wells currently produce close to one billion bbl of water annually and deliver about 8% of total natural gas in the USA. The salinity of this produced water generally is lower than that of water from conventional petroleum wells; salinity commonly is 1,000-20,000 mg/L, but ranges from 200 to 150,000 mg/L TDS. Most CBM wells produce Na-HCO3-Cl type water that is low in trace metals and has no reported NORMs. This water generally has no oil and grease and has relatively low (2-10 mg/L) dissolved organic carbon (DOC), but its organic composition has not been characterized in detail. The water is disposed of by injection into saline aquifers, through evaporation and/or percolation in disposal pits, road spreading, and surface discharge. Water that has low (<1,000 mg/L TDS) salinity and sodium adsorption ratio (SAR) is considered acceptable for irrigation, surface discharge and for injection into freshwater aquifers. Because groundwater associated with coal, especially with lignite and subbituminous coal, is known to contain a variety of toxic or potentially toxic organics, including hydroxyphenols and PAHs, the organic and inorganic compositions of CBM waters should be systematically characterized and their potential for harm to human health, crops and the environment carefully evaluated prior to its addition to existing water supplies. As an alternative to costly disposal, lower salinity produced water from high-yield CBM wells is being considered for reclamation. The treated water would be a valuable new water resource, especially in the arid western USA. The feasibility and cost of reclaiming produced water to meet irrigation, industrial and drinking water standards was evaluated in a 10 gpm pilot field study. The estimated treatment cost was high at about 0.39/bbl (3,000/acre-ft) for potable water, but would be substantially lower and competitive for irrigation and industrial uses in some arid regions of the USA.

  12. Hydrological, water-quality, and ecological data for streams in Independence, Missouri, June 2005 through September 2013

    USGS Publications Warehouse

    Niesen, Shelley L.; Christensen, Eric D.

    2015-01-01

    Water-quality, hydrological, and ecological data collected from June 2005 through September 2013 from the Little Blue River and smaller streams within the City of Independence, Missouri, are presented in this report. These data were collected as a part of an ongoing cooperative study between the U.S. Geological Survey and the City of Independence Water Pollution Control Department to characterize the water quality and ecological condition of Independence streams. The quantities, sources of selected constituents, and processes affecting water quality and aquatic life were evaluated to determine the resulting ecological condition of streams within Independence. Data collected for this study fulfill the municipal separate sewer system permit requirements for the City of Independence and can be used to provide a baseline with which city managers can determine the effectiveness of current (2014) and future best management practices within Independence. Continuous streamflow and water-quality data, collected during base flow and stormflow, included physical and chemical properties, inorganic constituents, common organic micro-constituents, pesticides in streambed sediment and surface water, fecal indicator bacteria and microbial source tracking data, and suspended sediment. Dissolved oxygen, pH, specific conductance, water temperature, and turbidity data were measured continuously at seven sites within Independence. Base-flow and stormflow samples were collected at eight gaged and two ungaged sites. Fecal sources samples were collected for reference for microbial source tracking, and sewage influent samples were collected as additional source samples. Dry-weather screening was done on 11 basins within Independence to identify potential contaminant sources to the streams. Benthic macroinvertebrate community surveys and habitat assessments were done on 10 stream sites and 2 comparison sites outside the city. Sampling and laboratory procedures and quality-assurance and

  13. Factors influencing stream water transit times in tropical montane watersheds

    NASA Astrophysics Data System (ADS)

    Muñoz-Villers, L. E.; Geissert, D. R.; Holwerda, F.; McDonnell, J. J.

    2015-10-01

    Stream water mean transit time (MTT) is a fundamental hydrologic parameter that integrates the distribution of sources, flow paths and storages present in catchments. However, in the tropics little MTT work has been carried out, despite its usefulness for providing important information on watershed functioning at different spatial scales in (largely) ungauged basins. In particular, very few studies have quantified stream MTTs and related to catchment characteristics in tropical montane regions. Here we examined topographic, land use/cover and soil hydraulic controls on baseflow transit times for nested watersheds (0.1-34 km2) within a humid mountainous region, underlain by volcanic soil (Andisols) in central Veracruz (eastern Mexico). We used a 2 year record of bi-weekly isotopic composition of precipitation and stream baseflow data to estimate MTT. Land use/cover and topographic parameters (catchment area and form, drainage density, slope gradient and length) were derived from GIS analysis. Soil water retention characteristics, and depth and permeability of the soil-bedrock interface were obtained from intensive field measurements and laboratory analysis. Results showed that baseflow MTT ranged between 1.2 and 2.7 years across the 12 study catchments. Overall, MTTs across scales were mainly controlled by catchment slope and the permeability observed at the soil-bedrock interface. In association with topography, catchment form, land cover and the depth to the soil-bedrock interface were also identified as important features influencing baseflow MTTs. The greatest differences in MTTs were found at the smallest (0.1-1.5 km2) and the largest scales (14-34 km2). Interestingly, longest stream MTTs were found in the headwater cloud forest catchments.

  14. Modelling inorganic biocide emission from treated wood in water.

    PubMed

    Tiruta-Barna, Ligia; Schiopu, Nicoleta

    2011-09-15

    The objective of this work is to develop a chemical model for explaining the leaching behaviour of inorganic biocides from treated wood. The standard leaching test XP CEN/TS14429 was applied to a commercial construction material made of treated Pinus sylvestris (Copper Boron Azole preservative). The experimental results were used for developing a chemical model under PHREEQC(®) (a geochemical software, with LLNL, MINTEQ data bases) by considering the released species detected in the eluates: main biocides Cu and B, other trace biocides (Cr and Zn), other elements like Ca, K, Cl, SO(4)(-2), dissolved organic matter (DOC). The model is based on chemical phenomena at liquid/solid interfaces (complexation, ion exchange and hydrolysis) and is satisfactory for the leaching behaviour representation. The simulation results confronted with the experiments confirmed the hypotheses of: (1) biocide fixation by surface complexation reactions with wood specific sites (carboxyl and phenol for Cu, Zn, Cr(III), aliphatic hydroxyl for B, ion exchange to a lesser extent) and (2) biocide mobilisation by extractives (DOC) coming from the wood. The maximum of Cu, Cr(III) and Zn fixation occurred at neutral pH (including the natural pH of wood), while B fixation was favoured at alkaline pH. PMID:21794983

  15. Effects of Land Use on Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon (DOC) and Dissolved Inorganic Carbon (DIC) in Southeastern US Piedmont Headwater Streams

    EPA Science Inventory

    Stable carbon isotopic composition (delta 13C) and concentrations of DOC and DIC were measured in stream water samples collected monthly in 15 headwater streams from an area with extensive poultry and cattle production and a rapidly growing human population. Linear regression te...

  16. Assessment of water quality in streams draining coal-producing areas in Ohio

    USGS Publications Warehouse

    Pfaff, C.L.; Helsel, D.R.; Johnson, D.P.; Angelo, C.G.

    1981-01-01

    Quality of water in 150 sites in the coal-producing areas of eastern Ohio was studied in a two-phase investigation between May 1975 and August 1976. Results of phase one, a reconnaissance to determine the occurrence of certain inorganic and organic constituents and to relate their occurrence to coal mining, indicated that acid mine drainage generally occured where abandoned drift or abandoned strip mines were located. Streams affected by such mines contained concentrations of dissolved sulfate and iron greater than 250 milligrams per liter and 5,000 micrograms per liter, respectively, and exhibited pH values less than 4.5. Areas characterized by reclaimed or active strip mines showed few instances of acid drainage (pH values were generally greater than 7.0). Iron concentrations in these regions generally were less than 500 micrograms per liter, with dissolved-sulfate concentrations ranging from 22 to 7,000 milligrams per liter. Phase two was a detailed study of four small baisn sampled during the first phase and found to represent different types of mining. The objective was to determine whether water-quality degradation within the basins was due to coal mining. Flows from two basins, one containing abandoned drift mines and the other abandoned strip mines, became increasingly acidic (pH values less than 4.5) downstream, and had high iron and dissolved sulfate concentrations (above 5,000 micrograms per liter and 250 milligrams per liter, respectively). Sources of acidity were tributaries that drained directly from the mines. The other two basins, one containing reclaimed strip mines and the other active strip mines, exhibited no acidic drainage; streams in both basins had pH values greater than 7.0 and iron concentrations below 500 micrograms per liter. Presence of active surface mining seemed to have little effect on dissolved sulfate concentrtions, as only streams in the reclaimed basin had high concentrations(usually over 2,000 milligrams per liter).

  17. Equilibrium phase diagrams and water absorption properties of aqueous mixtures of malonic acid and inorganic salts.

    NASA Astrophysics Data System (ADS)

    Salcedo, D.; Salgado-Olea, G.

    2006-12-01

    Tropospheric aerosols are usually complex mixtures of inorganic and organic components. Although the thermodynamic properties of inorganic aerosols have been widely studied, the effect of organics on such properties is still under discussion. Solubility in water, water activity of aqueous solutions, deliquescence relative humidity (DRH), eutonic composition, and eutonic DRH were determined for bulk mixtures of malonic acid with ammonium sulfate, ammonium bisulfate, and ammonium nitrate at 25oC over the full range of composition (from 0 wt% to the solubility limit of the mixture components). The data was used to construct equilibrium phase diagrams, which show the phase of the mixtures as a function of total composition, dry mixture composition, water content, and ambient relative humidity. Measured water activity of liquid solutions was compared with an extended Zdanovskii-Stokes-Robinson (ZSR) expression, which then was used to predict water absorption of the mixtures.

  18. Interfacial water thickness at inorganic nanoconstructs and biomolecules: Size matters

    NASA Astrophysics Data System (ADS)

    Cardellini, Annalisa; Fasano, Matteo; Chiavazzo, Eliodoro; Asinari, Pietro

    2016-04-01

    Water molecules in the proximity of solid nanostructures influence both the overall properties of liquid and the structure and functionality of solid particles. The study of water dynamics at solid-liquid interfaces has strong implications in energy, environmental and biomedical fields. This article focuses on the hydration layer properties in the proximity of Carbon Nanotubes (CNTs) and biomolecules (proteins, polypeptides and amino acids). Here we show a quantitative relation between the solid surface extension and the characteristic length of water nanolayer (δ), which is confined at solid-liquid interfaces. Specifically, the size dependence is attributed to the limited superposition of nonbonded interactions in case of small molecules. These results may facilitate the design of novel energy or biomedical colloidal nanosuspensions, and a more fundamental understanding of biomolecular processes influenced by nanoscale water dynamics.

  19. IDENTIFICATION AND DISTRIBUTION OF INORGANIC COMPONENTS IN WATER: WHAT TO MEASURE

    EPA Science Inventory

    The chemical forms of inorganic components in water are widely varied and range from simple aquo complexes in solution to complicated silicate minerals in suspension. A variety of techniques are used to determine the total quantities of components in a particular aqueous environm...

  20. WORKSHOP ON MONITORED NATURAL ATTENUATION OF INORGANIC CONTAMINANTS IN GROUND WATER

    EPA Science Inventory

    The Office of Research and Development (ORD) has developed a one-day seminar to present an overview of site characterization approaches to support evaluation of the potential for Monitored Natural Attenuation (MNA) as a remedy for inorganic contaminants in ground water. These sem...

  1. Nuclear magnetic resonance in water solutions of inorganic salts in vitreous and liquid states

    SciTech Connect

    Lundin, A. G. Koryavko, N. A.; Chichikov, S. A.

    2013-05-15

    Peculiarities of the behavior of water solutions of inorganic salts at temperatures of {approx}(120-150) K are examined. At these temperatures the solutions are in the vitreous state. At higher temperatures (up to 240 K) the solutions may be in metastable liquid, crystalline, or usual liquid states.

  2. TREATMENT TECHNOLOGY TO MEET THE INTERIM PRIMARY DRINKING WATER REGULATIONS FOR INORGANICS

    EPA Science Inventory

    The EPA established drinking water regulations for ten inorganic substances and radionuclides that became effective on June 24, 1977. As a result of these regulations, many communities may be required to construct new treatment facilities or to modify or improve on existing ones....

  3. TREATMENT TECHNOLOGY TO MEET THE INTERIM PRIMARY DRINKING WATER REGULATIONS FOR INORGANICS: PART 4

    EPA Science Inventory

    EPA established drinking water regulations for ten inorganic substances and radionuclides that became effective on June 24, 1977. As a result of these new regulations, many communities may be required to construct new treatment facilities or to modify existing ones. This paper on...

  4. INORGANIC SPECIES IN WATER: ECOLOGICAL SIGNIFICANCE AND ANALYTICAL NEEDS. A LITERATURE REVIEW

    EPA Science Inventory

    Representative studies of the environmental significance of inorganic species (as opposed to total-element content) in water are reviewed. The effects of chemical forms on human health and on plant and animal life, and the roles of valence state, ionization, complexation, and ads...

  5. Monitored Natural Attenuation of Inorganic Contaminants in Ground Water Volume 1 – Technical Basis for Assessment

    EPA Science Inventory

    This document represents the first volume of a set of three volumes that address the technical basis and requirements for assessing the potential applicability of MNA as part of a ground-water remedy for plumes with non-radionuclide and/or radionuclide inorganic contaminants. Vo...

  6. Modifying Polymer Flocculants for the Removal of Inorganic Phophate from Water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to strong hydrogen bonding interactions, thiourea has been shown to have a high affinity for anions such as inorganic phosphate. The interaction between phosphate and thiourea has been used to develop technologies that can detect and even remove phosphate from water. This research investigates t...

  7. Increasing the water temperature of a 2nd order stream reach: Hydraulic aspects of a whole-stream manipulative experiment

    NASA Astrophysics Data System (ADS)

    de Lima, João L. M. P.; Canhoto, Cristina

    2015-04-01

    What will happen when water temperatures of streams increases, due to climate changes or in connection with rapidly changing human systems? Trying to answer to this question a whole-stream manipulative experiment was undertaken, where an increase in water temperature was artificially induced on a 2nd order stream reach. The main objective of this poster is to describe this experiment focusing on the design of the hydraulic system. The system maintained a steady flow while allowing natural variation in abiotic factors and was successfully used to evaluate the effects of warming on a stream ecosystem at several levels of biological organization. A constant flow of stream water was controlled by a hydraulic setup (~22m long; ~1.5m width) subdivided into two independent channels. One channel of the study reach received heated water (~3°C above the other), while the other received water at stream ambient temperature. The warming system maintained a steady gravity controlled flow making use of weirs and valves.

  8. Horses, Cows, and Water Quality: Prioritizing Stream Restoration Sites

    NASA Astrophysics Data System (ADS)

    Lewis, R. A.; Ambers, R. K.

    2002-05-01

    In order to prioritize sites for a stream restoration project, water quality testing is being done in two small, partly forested watersheds on the Sweet Briar College campus east of the Blue Ridge Mountains of Virginia. The 1.3 km2 watershed of Dairy Creek contains a former dairy operation (now hayfields) and athletic fields. The 0.7 km2 watershed of Fern Creek contains an actively used horse pasture, riding, and stable area. The goals of this study are: (1) to determine which stream would benefit more from establishing or improving a forested riparian buffer zone and (2) to collect baseline water quality data which can be used in future years to monitor the effectiveness of the restoration project and other land management practices. Ten sites along the main stems and tributary streams in the two watersheds were chosen for water quality measurements. When water samples are collected, discharge is also determined at each site by dilution gauging using a conductivity logger. Water samples are tested in the lab for pH, turbidity, nitrate-nitrogen, orthophosphate, total phosphate, and fecal and total coloform bacteria. Total and orthophosphate and pH show no systematic downstream variation or difference between the two watersheds. In contrast, nitrate increases downstream and is positively correlated with conductivity and the upstream area of non-forested land. Nitrate concentrations in the Dairy Creek watershed are significantly higher than in the Fern Creek watershed. Fecal and total coloform counts also tend to be higher in Dairy than in Fern Creek, but the numbers vary widely. Although discharge increases downstream in a predictable way, it does not correlate well with any of the measured constituents. Despite the fact that the riding center is functioning but the dairy operation is not, these preliminary data suggest that water quality in the Dairy Creek system is poorer than in Fern Creek. Further investigation is needed to identify non-point sources of nutrient

  9. Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway, Adjacent to a Closed Landfill, near Roanoke, Virginia: 1999

    USGS Publications Warehouse

    Ebner, Donna Belval; Cherry, Donald S.; Currie, Rebecca J.

    2004-01-01

    A study was done of the effects of a closed landfill on the quality of water and streambed sediment and the benthic macroinvertebrate community of an unnamed stream and its tributary that flow through Blue Ridge Parkway lands in west-central Virginia. The primary water source for the tributary is a 4-inch polyvinyl chloride (PVC) pipe that protrudes from the slope at the base of the embankment bordering the landfill. An unusual expanse of precipitate was observed in the stream near the PVC pipe. Stream discharge was measured and water and streambed sediment samples were collected at a nearby reference site and at three sites downstream of the landfill in April and September 1999. Water samples were analyzed for major ions, nitrate, total and dissolved metals, total dissolved solids, total organic carbon, and volatile and semivolatile organic compounds, including organochlorine pesticides and polychlorinated biphenyls (PCBs). Streambed sediment samples were analyzed for total metals, total organic carbon, percent moisture, and volatile and semivolatile organic compounds, including organochlorine pesticides and PCBs. The benthic macroinvertebrate community within the stream channel also was sampled at the four chemical sampling sites and at one additional site in April and September. Each of the five sites was assessed for physical habitat quality. Water collected periodically at the PVC pipe discharge between November 1998 and November 1999 was used to conduct 48-hour acute and 7-day chronic toxicity tests using selected laboratory test organisms. Two 10-day chronic toxicity tests of streambed sediments collected near the discharge pipe also were conducted. Analyses showed that organic and inorganic constituents in water from beneath the landfill were discharged into the sampled tributary. In April, 79 percent of inorganic constituents detected in water had their highest concentrations at the site closest to the landfill; at the same site, 59 percent of inorganic

  10. Testing a community water supply well located near a stream for susceptibility to stream contamination and low-flows.

    NASA Astrophysics Data System (ADS)

    Stewart-Maddox, N. S.; Tysor, E. H.; Swanson, J.; Degon, A.; Howard, J.; Tsinnajinnie, L.; Frisbee, M. D.; Wilson, J. L.; Newman, B. D.

    2014-12-01

    A community well is the primary water supply to the town of El Rito. This small rural town in is located in a semi-arid, mountainous portion of northern New Mexico where water is scarce. The well is 72 meters from a nearby intermittent stream. Initial tritium sampling suggests a groundwater connection between the stream and well. The community is concerned with the sustainability and future quality of the well water. If this well is as tightly connected to the stream as the tritium data suggests, then the well is potentially at risk due to upstream contamination and the impacts of extended drought. To examine this, we observed the well over a two-week period performing pump and recovery tests, electrical resistivity surveys, and physical observations of the nearby stream. We also collected general chemistry, stable isotope and radon samples from the well and stream. Despite the large well diameter, our pump test data exhibited behavior similar to a Theis curve, but the rate of drawdown decreased below the Theis curve late in the test. This decrease suggests that the aquifer is being recharged, possibly through delayed yield, upwelling of groundwater, or from the stream. The delayed yield hypothesis is supported by our electrical resistivity surveys, which shows very little change in the saturated zone over the course of the pump test, and by low values of pump-test estimated aquifer storativity. Observations of the nearby stream showed no change in stream-water level throughout the pump test. Together this data suggests that the interaction between the stream and the well is low, but recharge could be occurring through other mechanisms such as delayed yield. Additional pump tests of longer duration are required to determine the exact nature of the aquifer and its communication with the well.

  11. Biogeochemical characteristics of a polluted urban stream (Anacostia River, Washington DC, USA): inorganic minerals, nutrients and allochthonous vs. autochthonous production

    NASA Astrophysics Data System (ADS)

    Sarraino, S.; Frantz, D.; Bushaw-Newton, K.; MacAvoy, S. E.

    2011-12-01

    The Anacostia River in Washington, D.C. is among the 10 most contaminated rivers in the USA, containing sewage, metals, PAHs, and PCBs. The biogeochemical characteristics of tidal freshwater urban rivers, including the Anacostia, remain largely unstudied. This study examined base-flow geochemistry and nutrients dynamics over a one-year period (April 2010- May 2011), concentrating on inorganics (Ca, Mg, Na, S, K, P, NO3, NH4, PO4, B, Ba, Ni, Co), organic hydrocarbons, sediment and water column particulate C, N and S stable isotopes and total organic carbon. Water and sediment were sampled from three tidal freshwater sites along the Anacostia River approximately every 8 weeks. δ15N values of sediment and water column particulates ranged from +2 to +9%, with the most enriched values occurring downstream (+4 to +9%). While these values may not reflect sewage inputs, an overall enrichment was observed between spring and late summer, which may indicate microbial activity. δ13C values exhibited slightly more variation and ranged from -30 to -25%. All sites showed relative depletion in early summer compared with spring or late summer/fall. C/N ratios were generally between 13-19 in sediments, indicating autochthonous origins. Water nutrients (NO3 and NH4) demonstrated seasonal fluxes; all sites showed a peak in nutrients during early summer (June) and subsequent decline. Overall, NO3 ranged from about 0.2 to 3.3 mg/L and NH4 ranged from 0 to 1.7 μg/L. GC-MS analysis showed notable compounds such as anthraquinone (a possible carcinogen), steroid hormones and several odd-chain and branched fatty acids. Principle Component Analysis (PCA) of the geochemical data suggests the strongest control of water chemistry (25-39%) is a Ca/Mg component that was also strongly associated with nitrate and K at 2 of the 3 sites. The second component (25%) was strongly associated with Na. The possibility that cement influences the geochemistry of this urban river continues to be examined.

  12. Field and Laboratory Studies of Reactions between Atmospheric Water Soluble Organic Acids and Inorganic Particles

    SciTech Connect

    Wang, Bingbing; Kelly, Stephen T.; Sellon, Rachel E.; Shilling, John E.; Tivanski, Alexei V.; Moffet, Ryan C.; Gilles, Mary K.; Laskin, Alexander

    2013-06-25

    Atmospheric inorganic particles undergo complex heterogeneous reactions that change their physicochemical properties. Depletion of chloride in sea salt particles was reported in previous field studies and was attributed to the acid displacement of chlorides with inorganic acids, such as nitric and sulfuric acids [1-2]. Recently, we showed that NaCl can react with water soluble organic acids (WSOA) and release gaseous hydrochloric acid (HCl) resulting in formation of organic salts [3]. A similar mechanism is also applicable to mixed WSOA/nitrate particles where multi-phase reactions are driven by the volatility of nitric acid. Furthermore, secondary organic material, which is a complex mixture of carboxylic acids, exhibits the same reactivity towards chlorides and nitrates. Here, we present a systematic study of reactions between atmospheric relevant WSOA, SOM, and inorganic salts including NaCl, NaNO3, and Ca(NO3)2 using complementary micro-spectroscopy analysis.

  13. Diagnostic tools for mixing models of stream water chemistry

    USGS Publications Warehouse

    Hooper, R.P.

    2003-01-01

    Mixing models provide a useful null hypothesis against which to evaluate processes controlling stream water chemical data. Because conservative mixing of end-members with constant concentration is a linear process, a number of simple mathematical and multivariate statistical methods can be applied to this problem. Although mixing models have been most typically used in the context of mixing soil and groundwater end-members, an extension of the mathematics of mixing models is presented that assesses the "fit" of a multivariate data set to a lower dimensional mixing subspace without the need for explicitly identified end-members. Diagnostic tools are developed to determine the approximate rank of the data set and to assess lack of fit of the data. This permits identification of processes that violate the assumptions of the mixing model and can suggest the dominant processes controlling stream water chemical variation. These same diagnostic tools can be used to assess the fit of the chemistry of one site into the mixing subspace of a different site, thereby permitting an assessment of the consistency of controlling end-members across sites. This technique is applied to a number of sites at the Panola Mountain Research Watershed located near Atlanta, Georgia.

  14. High Surface Area Inorganic Membrane for Water Removal

    SciTech Connect

    2008-12-01

    This factsheet describes a research project whose objective is to demonstrate the fabrication and performance advantages of minichannel planar membrane modules made of porous metallic supports of surface area packing density one order of magnitude higher than the conventional membrane tube. The new, transformational, ceramic/metallic, hybrid membrane technology will be used for water/ethanol separations and reduce energy consumption by >20% over distillation and adsorption.

  15. Effect of boiling regime on melt stream breakup in water

    SciTech Connect

    Spencer, B.W.; Gabor, J.D.; Cassulo, J.C.

    1986-01-01

    A study has been performed examining the breakup and mixing behavior of an initially coherent stream of high-density melt as it flows downward through water. This work has application to the quenching of molten core materials as they drain downward during a postulated severe reactor accident. The study has included examination of various models of breakup distances based upon interfacial instabilities dominated either by liquid-liquid contact or by liquid-vapor contact. A series of experiments was performed to provide a data base for assessment of the various modeling approaches. The experiments involved Wood's metal (T/sub m/ = 73/sup 0/C, rho = 9.2 g/cm/sup 3/, d/sub j/ = 20 mm) poured into a deep pool of water. The temperature of the water and wood's metal were varied to span the range from single-phase, liquid-liquid contact to the film boiling regime. Experiment results showed that breakup occurred largely as a result of the spreading and entrainment from the leading edge of the jet. However, for streams of sufficient lengths a breakup length could be discerned at which there was no longer a coherent central core of the jet to feed the leading edge region. The erosion of the vertical trailing column is by Kelvin-Helmoltz instabilities and related disengagement of droplets from the jet into the surrounding fluid. For conditions of liquid-liquid contact, the breakup length has been found to be about 20 jet diameters; when substantial vapor is produced at the interface due to heat transfer from the jet to the water, the breakup distance was found to range to as high as 50 jet diameters. The former values are close to the analytical prediction of Taylor, whereas the latter values are better predicted by the model of Epstein and Fauske.

  16. Relation between urbanization and water quality of streams in the Austin area, Texas

    SciTech Connect

    Veenhuis, J.E.; Slade, R.M. )

    1990-01-01

    Selected water quality properties and constituents of stormflow and base flow at 18 sites on 11 streams in the Austin area, Texas, were compared to determine the relation between degree of urbanization and water quality. Sample sites were grouped into four development classifications based on percentage of impervious cover of the drainage basin. For each site and development classification, concentrations and densities of water quality properties and constituents in samples collected during base flow were compared. Except for dissolved solids, concentrations during the rising stage of stormflow generally were larger than during the falling stage. The concentrations in stormflow were larger than in base flow. For the five sites that had sufficient samples from each flow category for statistical comparisons, median concentrations in stormflow were significantly larger than in base flow. Concentrations in the rising stage were more variable and significantly larger than in the falling stage. Except for dissolved solids, median concentrations in samples collected during stormflow increased with increasing urbanization. Medians for base flow also were larger for more urban classifications. The ratio of the number of samples with detectable concentrations to total sample analyzed of 18 minor inorganic constituents and the concentrations of many of these constituents increased with increasing urbanization. Twenty-two of 42 synthetic organic compounds investigated were detected in one or more samples and were detected more frequently and in larger concentrations at sites with more urban classifications.

  17. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  18. Heat, chloride, and specific conductance as ground water tracers near streams

    USGS Publications Warehouse

    Cox, M.H.; Su, G.W.; Constantz, J.

    2007-01-01

    Commonly measured water quality parameters were compared to heat as tracers of stream water exchange with ground water. Temperature, specific conductance, and chloride were sampled at various frequencies in the stream and adjacent wells over a 2-year period. Strong seasonal variations in stream water were observed for temperature and specific conductance. In observation wells where the temperature response correlated to stream water, chloride and specific conductance values were similar to stream water values as well, indicating significant stream water exchange with ground water. At sites where ground water temperature fluctuations were negligible, chloride and/or specific conductance values did not correlate to stream water values, indicating that ground water was not significantly influenced by exchange with stream water. Best-fit simulation modeling was performed at two sites to derive temperature-based estimates of hydraulic conductivities of the alluvial sediments between the stream and wells. These estimates were used in solute transport simulations for a comparison of measured and simulated values for chloride and specific conductance. Simulation results showed that hydraulic conductivities vary seasonally and annually. This variability was a result of seasonal changes in temperature-dependent hydraulic conductivity and scouring or clogging of the streambed. Specific conductance fits were good, while chloride data were difficult to fit due to the infrequent (quarterly) stream water chloride measurements during the study period. Combined analyses of temperature, chloride, and specific conductance led to improved quantification of the spatial and temporal variability of stream water exchange with shallow ground water in an alluvial system. ?? 2007 National Ground Water Association.

  19. Large-scale penetration of Gulf Stream water onto the continental shelf north of Cape Hatteras

    NASA Technical Reports Server (NTRS)

    Gawarkiewicz, Glen; Church, Thomas M.; Luther, George W., III; Ferdelman, Timothy G.; Caruso, Michael

    1992-01-01

    The presence of Gulf Stream water on the continental shelf as much as 60 km north of Cape Hatteras was observed during a hydrographic cruise in the summer of 1990. Gulf Stream water was concentrated at mid-depth between 10 and 30 m and penetrated the shelfbreak front which normally separates the shelf water from slope water and Gulf Stream water. Velocities of Gulf Stream water in the upper 110 m of the water column along the 1000 m isobath indicated a flow of 18 to 25 cm/s directed towards the northwest. Gulf Stream water on the shelf is considered to be associated with low values of fluorescence, transmissivity, and nutrient concentrations relative to adjacent shelf water.

  20. Water quality of North Carolina streams. Chapter E

    SciTech Connect

    Harned, D.; Meyer, D.

    1983-01-01

    Interpretation of water-quality data for the Yadkin-Pee Dee River system, has identified water-quality variations, characterized the current condition of the river in reference to water-quality standards, estimated the degree of pollution caused by man, and evaluated long-term trends in concentrations of major dissolved constituents. Overall, the ambient water quality of the Yadkin-Pee Dee River system is satisfactory for most water uses. Iron and manganese concentrations are often above desirable levels, but they are not unusually high in comparison to other North Carolina streams. Lead concentrations also periodically rise above the recommended criterion for domestic water use. Mercury concentrations frequently exceed, and pH levels fall below, the recommended criteria for protection of aquatic life. Dissolved-oxygen levels, while generally good, are lowest at the Pee Dee near Rockingham, due to the station's location not far downstream from a lake. Suspended sediment is the most significant water-quality problem of the Yadkin-Pee Dee River. The major cation in the river is sodium and the major anions are bicarbonate and carbonate. Nutrient concentrations are high enough to allow rich algal growth. Eutrophication is currently a problem in the Yadkin-Pee Dee, particularly in High Rock Lake. Statistically significant trends show a pattern of increasing concentration of most dissolved constituents over time, with a leveling off and declines in the middle of late 1970's. Relatively steady increases in sulfate and in nitrate and a steady decrease in pH with time probably are largely due to the increasing acidity of atmospheric precipitation. 43 figs., 22 tabs.

  1. Analyzing Conductivity Profiles in Stream Waters Influenced by Mine Water Discharges

    NASA Astrophysics Data System (ADS)

    Räsänen, Teemu; Hämäläinen, Emmy; Hämäläinen, Matias; Turunen, Kaisa; Pajula, Pasi; Backnäs, Soile

    2015-04-01

    Conductivity is useful as a general measure of stream water quality. Each stream inclines to have a quite constant range of conductivity that can be used as a baseline for comparing and detecting influence of contaminant sources. Conductivity in natural streams and rivers is affected primarily by the geology of the watershed. Thus discharges from ditches and streams affect not only the flow rate in the river but also the water quality and conductivity. In natural stream waters, the depth and the shape of the river channel change constantly, which changes also the water flow. Thus, an accurate measuring of conductivity or other water quality indicators is difficult. Reliable measurements are needed in order to have holistic view about amount of contaminants, sources of discharges and seasonal variation in mixing and dilution processes controlling the conductivity changes in river system. We tested the utility of CastAway-CTD measuring device (SonTek Inc) to indicate the influence of mine waters as well as mixing and dilution occurring in the recipient river affected by treated dewatering and process effluent water discharges from a Finnish gold mine. The CastAway-CTD measuring device is a small, rugged and designed for profiling of depths of up to 100m. Device measures temperature, salinity, conductivity and sound of speed using 5 Hz response time. It has also built-in GPS which produces location information. CTD casts are normally used to produce vertical conductivity profile for rather deep waters like seas or lakes. We did seasonal multiple Castaway-CTD measurements during 2013 and 2014 and produced scaled vertical and horizontal profiles of conductivity and water temperature at the river. CastAway-CTD measurement pinpoints how possible contaminants behave and locate in stream waters. The conductivity profiles measured by CastAway-CTD device show the variation in maximum conductivity values vertically in measuring locations and horizontally in measured cross

  2. Eighteen Degree Water formation within the Gulf Stream during CLIMODE

    NASA Astrophysics Data System (ADS)

    Joyce, Terrence M.; Thomas, Leif N.; Dewar, William K.; Girton, James B.

    2013-07-01

    Analysis of wintertime CLIMODE data for 2007 indicates that a substantial portion of new Eighteen Degree Water (EDW) is likely ventilated within the eastward flowing Gulf Stream (GS) between 67°W and 52°W longitudes, possibly exceeding that formed elsewhere in the northern Sargasso Sea. Use of some global air-sea interaction data sets applied to the study region for Feb/Mar of 2007 indicate that this winter may have been anomalously energetic in air-sea exchange compared to the mean of the prior 19 yr. The largest heat and freshwater fluxes found directly over the meandering warm core of the Gulf Stream are capable of removing most of the subtropical heat anomaly of the GS, but cross-frontal fluxes of salinity are required to account for the observed regional salinity structure. An isopycnal diffusivity of ˜100 m2 s-1 is inferred from the salinity balance. This mixing would also account for the observation that EDW formed in the GS is slightly fresher than that formed in northern Sargasso Sea. The lateral flux of heat across the GS north wall also acts to cool the resulting EDW water, but the heat balance for EDW production is largely determined from GS advection and air-sea fluxes, in contrast to salinity. Based on oxygen saturation data, we estimate that 1.8-3.0 Sv-yr of new EDW is formed in the GS for the winter of 2007. EDW originating from the GS is generated in a separate location from where it is accumulated in the northern Sargasso Sea. This manner of EDW formation will produce unique characteristics of EDW found in the northern Sargasso Sea: ones that differ in T/S properties from that formed south of the GS under the more traditional 1D, cooling-driven convection process.

  3. Stream Water and Soil Water Chemistry Following the Table Mountain Wildfire, Washington

    NASA Astrophysics Data System (ADS)

    Roccanova, V. J.; Gazis, C. A.

    2013-12-01

    Severe wildfire occurrence in the Western United States increased throughout the 20th century and has continued to increase into the 21st century. Global climate change resulting from natural and anthropogenic sources is considered a contributor to this increase in wildfire severity. Fire suppression techniques developed in the early 20th century are also a factor in increased severe wildfire occurrence as they augment available fuel loads. Biomass burning releases nutrients that are held within trees and plants. Nitrogen, phosphorous, and calcium levels have been documented as increasing in stream waters as a result of wildfire. As severe wildfire occurrence increases, so does the likelihood that stream, and to a lesser extent groundwater, will be loaded with nutrients and sediments as a result of wildfire activity. Increased nutrient loads can cause algal blooms that deplete streams of oxygen, important to aquatic plants and animals that reside in these streams. These changes in water quality can also affect humans who depend on these streams for irrigation and drinking water purposes. The Table Mountain wildfire in Washington State was started by a lightning strike that occurred at approximately 8:00 PM on Saturday September 8th, 2012. The fire burned for approximately one month and was declared to be 100% contained on Friday October 5th, 2012. Over this period the fire burned a total of 171 square kilometers of forest. In this study multiple stream and soil water samples were collected from three types of area in the winter through summer following the fire: severely burned, moderately burned, and unburned. All areas sampled have similar bedrock and vegetation cover. These samples were analyzed for major ions and trace element concentrations. Select samples will also be analyzed for strontium isotope ratios. The results of these geochemical analyses will be presented. Because calcium and strontium have similar properties, their concentrations can be combined

  4. E. coli transport to stream water column from bottom sediments to the stream water column in base flow conditions

    NASA Astrophysics Data System (ADS)

    Pachepsky, Yakov; Shelton, Daniel; Stocker, Matthew

    2016-04-01

    E. coli as an indicator bacterium is commonly used to characterize microbiological water quality, to evaluate surface water sources for microbiological impairment, and to assess management practices that lead to the decrease of pathogens and indicator influx in surface water sources for recreation and irrigation. Bottom sediments present a large reservoir of fecal indicator bacteria that are known to be released to water column during high flow events caused by rainstorms and snowmelt. The objective of this work was to see if the influx of E. coli from sediments to water occurs also during base flow periods when groundwater rather than runoff provides the major water input to the stream. The experiment was carried out at the first-order creek in Maryland flowing in the riparian zone in base flow conditions. An inert tracer was released to creek water from the manifold for 5 hours. Streamflow and concentrations of E. coli and tracer were monitored in water 10 m below tracer release location, and at the downstream location at 450 m from the release location. The tracer mass recovered at the downstream location was close to the released tracer mass. We then could directly compare the total numbers of E. coli in volumes of water containing tracer at the upstream (release) location and the downstream location. There was a substantial (3 to 6 times) increase in flow between the upstream and downstream locations as well as the substantial increase in the E. coli total numbers in water (14 to 26 times). The average E. coli influx from the bottom sediment was about 400 cells m-2s-1. Although this value is about 2 to 5 times less than published E. coli release rates during high flow events, it still can substantially change the microbial water quality assessment without any input from animal agriculture or manure application. Interesting research objectives include finding out whether the transport of E. coli from bottom sediment to water column during the base flow periods

  5. Comparison of fish communities in a clean-water stream and an adjacent polluted stream

    SciTech Connect

    Reash, R.J.; Berra, T.M. )

    1987-10-01

    Fish populations were studied in two parallel tributaries of the Mohican River, Ohio: Clear Fork, relatively undisturbed; and Rocky Fork, which receives industrial discharges and sewage effluent. Water quality in Rocky Fork was significantly worse than the control stream with respect to heavy metals (Cr, Cu, Fe, Ni, and Zn) and ammonia concentrations. Fish species richness and diversity increased downstream in Clear Fork but decreased downstream in Rocky Fork. Pollution-intolerant species were present in the headwaters of Rocky Fork and at all sites of Clear Fork. Fish community similarity of fish communities between corresponding headwater sites was significantly greater than similarity of corresponding downstream reaches, using polluted and unpolluted sites for comparison. Both headwater sites were dominated numerically by generalized invertebrate-feeding fish. At downstream sites in Clear Fork benthic insectivores became dominant in Rocky Fork, generalized invertebrate-feeding fish were present. Fish communities at polluted sites had comparatively lower variability of both trophic structure rank and relative abundance. The smaller populations of fish in these sites were dominated by a few pollution-tolerant species.

  6. Facile fabrication of organic/inorganic nanotube heterojunction arrays for enhanced photoelectrochemical water splitting.

    PubMed

    Chen, Yingzhi; Li, Aoxiang; Yue, Xiaoqi; Wang, Lu-Ning; Huang, Zheng-Hong; Kang, Feiyu; Volinsky, Alex A

    2016-07-01

    Organic/inorganic heterojunction photoanodes are appealing for making concurrent use of the highly photoactive organic semiconductors, and the efficient dielectric screening provided by their inorganic counterparts. In the present work, organic/inorganic nanotube heterojunction arrays composed of TiO2 nanotube arrays and a semiconducting N,N-(dicyclohexyl) perylene-3,4,9,10-tetracarboxylic diimide (PDi) layer were fabricated for photoelectrochemical water splitting. In this arrayed architecture, a PDi layer with a tunable thickness was coated on anodic TiO2 nanotube arrays by physical vapor deposition, which is advantageous for the formation of a uniform layer and an adequate interface contact between PDi and TiO2. The obtained PDi/TiO2 junction exhibited broadened visible light absorption, and an effective interface for enhanced photogenerated electron-hole separation, which is supported by the reduced charge transfer resistance and prolonged excitation lifetime via impedance spectroscopy analysis and fluorescence emission decay investigations. Consequently, such a heterojunction photoanode was photoresponsive to a wide visible light region of 400-600 nm, and thus demonstrated a highly enhanced photocurrent density at 1.23 V vs. a reversible hydrogen electrode. Additionally, the durability of such a photoanode can be guaranteed after long-time illumination because of the geometrical restraint imposed by the PDi aggregates. These results pave the way to discover new organic/inorganic assemblies for high-performance photoelectric applications and device integration. PMID:26926569

  7. EFFECTS OF STREAM RESTORATION ON IN-STREAM WATER QUALITY IN AN URBAN WATERSHED

    EPA Science Inventory

    The purpose of this on-going project is to provide information to Municipal Separate Storm Sewer System (MS4s) operators and states on the performance of selected best management practices (BMPs), specifically, stream restoration techniques, on improving biological and in-stream ...

  8. Control of nitrogen export from watersheds by headwater streams.

    PubMed

    Peterson, B J; Wollheim, W M; Mulholland, P J; Webster, J R; Meyer, J L; Tank, J L; Marti, E; Bowden, W B; Valett, H M; Hershey, A E; McDowell, W H; Dodds, W K; Hamilton, S K; Gregory, S; Morrall, D D

    2001-04-01

    A comparative (15)N-tracer study of nitrogen dynamics in headwater streams from biomes throughout North America demonstrates that streams exert control over nutrient exports to rivers, lakes, and estuaries. The most rapid uptake and transformation of inorganic nitrogen occurred in the smallest streams. Ammonium entering these streams was removed from the water within a few tens to hundreds of meters. Nitrate was also removed from stream water but traveled a distance 5 to 10 times as long, on average, as ammonium. Despite low ammonium concentration in stream water, nitrification rates were high, indicating that small streams are potentially important sources of atmospheric nitrous oxide. During seasons of high biological activity, the reaches of headwater streams typically export downstream less than half of the input of dissolved inorganic nitrogen from their watersheds. PMID:11292868

  9. Methods for determination of inorganic substances in water and fluvial sediments

    USGS Publications Warehouse

    Fishman, Marvin J., (Edited By); Friedman, Linda C.

    1989-01-01

    Chapter Al of the laboratory manual contains methods used by the U.S. Geological Survey to analyze samples of water, suspended sediments, and bottom material for their content of inorganic constituents. Included are methods for determining the concentration of dissolved constituents in water, the total recoverable and total of constituents in water-suspended sediment samples, and the recoverable and total concentrations of constituents in samples of bottom material. The introduction to the manual includes essential definitions and a brief discussion of the use of significant figures in calculating and reporting analytical results. Quality control in the water-analysis laboratory is discussed, including the accuracy and precision of analyses, the use of standard-reference water samples, and the operation of an effective quality-assurance program. Methods for sample preparation and pretreatment are given also. A brief discussion of the principles of the analytical techniques involved and their particular application to water and sediment analysis is presented. The analytical methods of these techniques are arranged alphabetically by constituent. For each method, the general topics covered are the application, the principle of the method, the interferences, the apparatus and reagents required, a detailed description of the analytical procedure, reporting results, units and significant figures, and analytical precision data, when available. More than 126 methods are given for the determination of 70 inorganic constituents and physical properties of water, suspended sediment, and bottom material.

  10. Evaluating stream water quality through land use analysis in two grassland catchments: impact of wetlands on stream nitrogen concentration.

    PubMed

    Hayakawa, A; Shimizu, M; Woli, K P; Kuramochi, K; Hatano, R

    2006-01-01

    We evaluated the impacts of natural wetlands and various land uses on stream nitrogen concentration in two grassland-dominated catchments in eastern Hokkaido, Japan. Analyzing land use types in drainage basins, measuring denitrification potential of its soil, and water sampling in all seasons of 2003 were performed. Results showed a highly significant positive correlation between the concentration of stream NO3-N and the proportion of upland area in drainage basins in both catchments. The regression slope, which we assumed to reflect the impact on water quality, was 24% lower for the Akkeshi catchment (0.012 +/- 0.001) than for the Shibetsu catchment (0.016 +/- 0.001). In the Akkeshi catchment, there was a significant negative correlation between the proportion of wetlands in the drainage basins and stream NO3-N concentration. Stream dissolved organic nitrogen (DON) and carbon (DOC) concentrations were significantly higher in the Akkeshi catchment. Upland and urban land uses were strongly linked to increases in in-stream N concentrations in both catchments, whereas wetlands and forests tended to mitigate water quality degradation. The denitrification potential of the soils was highest in wetlands, medium in riparian forests, and lowest in grasslands; and was significant in wetlands and riparian forests in the Akkeshi catchment. The solubility of soil organic carbon (SOC) and soil moisture tended to determine the denitrification potential. These results indicate that the water environment within the catchments, which influences denitrification potential and soil organic matter content, could have caused the difference in stream water quality between the two catchments. PMID:16510707

  11. Stream Temperature Variability as an Indicator of Groundwater-Surface Water Interactions in Two Groundwater-Fed Streams

    NASA Astrophysics Data System (ADS)

    Middleton, M.; Allen, D. M.

    2009-12-01

    Water temperature can be a useful tool in assessing the nature and the locations of groundwater - surface water interactions, particularly during low flow periods. In this study, a network of forty calibrated temperature (TidBit) loggers was installed in two groundwater-fed streams (Fishtrap and Bertrand Creeks) in the Lower Fraser Valley of British Columbia and northern Washington State. These streams have precipitation-driven flow regimes and are presumed to be sustained by baseflow during the annual low-flow period which lags minimum precipitation by approximately one month. In these particular streams, understanding groundwater-surface water interactions has been identified data gap in the development of recovery strategies for maintaining ecosystem health and habitat for two endangered fish species, the Nooksack Dace and Salish Sucker. From July 2008 to June 2009, stream temperature and discharge, groundwater temperature and level, and climate were monitored consecutively over two low-flow seasons with the objective of quantifying the spatial and temporal variability within each stream, as well as differences and trends between the streams. The temperature logger networks were installed over 50 m of channel or less at one site on each stream, as well as at two additional sites on Fishtrap Creek for regional coverage. Within each stream, the network of temperature loggers showed the variability in water temperature over a short distance of the channel. In Fishtrap Creek, among 15 dataloggers, the mean variability was 1.3oC, and in Bertrand Creek, among 19 dataloggers, the mean variability was 0.7oC. Fishtrap Creek water temperature ranged from 0.4oC to 17.6oC, showing less variability than Bertrand Creek, which ranged from -0.1oC to 20.8oC. The groundwater temperatures remained relatively stable throughout the year and ranged from 10.1oC to 12.0oC. Fishtrap Creek water temperature patterns were generally stable and mimicked groundwater temperature variations

  12. The Effect of Biogeochemical and Hydrologic Processes on Nitrogen in Stream Water Originating From Coal-Bed Methane Supply Wells

    NASA Astrophysics Data System (ADS)

    Smith, R. L.; Repert, D. A.; Hart, C. P.

    2003-12-01

    Water obtained from coal-bed methane (CBM) wells typically contains a variety of reduced chemical constituents, including methane, metal ions, particulate and dissolved organic carbon, and ammonium. In many locales in Wyoming and Montana, CBM water is disposed via discharge to stream channels and reservoirs. Though it is likely that biogeochemical and hydrologic processes will result in major changes in the chemical composition of these waters with subsequent downstream transport, few studies have actually examined these water quality changes or their ecological impacts. A field study was conducted in the Powder River Basin, WY to document changes in solute composition within stream channels below discharge points of CBM water. Particular emphasis was placed on nitrogen and nitrogen cycling processes. Concentration ranges in discharge water were: DOC, 200-350 μ M; alkalinity, 40-50 meq/L; specific conductance, 3.3-4.0 mS/cm; ammonium, 350-400 μ M; and pH, 7.2-7.3. Ammonium concentrations decreased with transport distance via nitrification, with subsequent increases in nitrite and nitrate. Within a single discharge channel, nitrite concentrations increased with travel distance, peaking at >100 μ M at 100-200 m, but also exhibited a strong diel pattern that was inversely related to incident light. Nitrite production/consumption processes differed significantly within in-stream incubation chambers, depending upon location relative to the CBM discharge point and time of day. In the main channel, subject to several CBM discharge points, diel nitrite concentrations were more constant at a fixed station, but did increase with distance downstream. Main channel total inorganic nitrogen remained relatively constant ( ˜400 μ M N) with distance (>5 km), suggesting little net nitrogen removal. The results of this study suggest that CBM discharge can serve as a significant source of dissolved nitrogen to western watersheds, with oxidative processes resulting in nitrate and

  13. Biocompatible inorganic fullerene-like molybdenum disulfide nanoparticles produced by pulsed laser ablation in water.

    PubMed

    Wu, Haihua; Yang, Rong; Song, Baomin; Han, Qiusen; Li, Jingying; Zhang, Ying; Fang, Yan; Tenne, Reshef; Wang, Chen

    2011-02-22

    We report on the synthesis of inorganic fullerene-like molybdenum disulfide (MoS(2)) nanoparticles by pulsed laser ablation (PLA) in water. The final products were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and resonance Raman spectroscopy, etc. Cell viability studies show that the as-prepared MoS(2) nanoparticles have good solubility and biocompatibility, which may show a great potential in various biomedical applications. It is shown that the technique of PLA in water also provides a green and convenient method to synthesize novel nanomaterials, especially for biocompatible nanomaterials. PMID:21230008

  14. EVALUATION OF STREAMBANK RESTORATION ON IN-STREAM WATER QUALITY IN AN URBAN WATERSHED

    EPA Science Inventory

    The objectives of this on-going project are to: investigate the effectiveness of streambank restoration techniques on increasing available biological habitat and improving in-stream water quality in an impaired stream; and, demonstrate the utility of continuous water-quality moni...

  15. Water quality effects of herded stream crossings by domestic sheep bands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On rangelands, free-ranging or loosely-herded domestic sheep tend not to linger in shrub-dominated riparian areas thus limiting their impacts on stream water quality. The water quality effects when sheep are tightly-herded during stream crossings, however, are largely unknown. In this study, downs...

  16. Linking nitrogen management, seep chemistry, and stream water quality in two agricultural headwater watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian seepage zones in headwater agricultural watersheds represent important sources of nitrate-nitrogen (NO3-N) to surface waters, often connecting N-rich groundwater systems to streams. In this study, we examined how NO3-N concentrations in seep and stream water were affected by NO3-N processin...

  17. Considerations for sampling inorganic constituents in ground water using diffusion samplers

    USGS Publications Warehouse

    Vroblesky, D.A.; Petkewich, M.D.; Campbell, T.R.

    2002-01-01

    Data indicate that nylon-screen and dialysis diffusion samplers are capable of obtaining concentrations of inorganic solutes in ground water from wells that closely correspond to concentrations obtained by low-flow sampling. Conservative solutes, such as chloride, can be sampled by filling the diffusion samplers with oxygenated water. The samplers should be filled with anaerobic water for sampling redoxsensitive solutes. Oxidation of iron within the samplers, either by using aerobic fill water or by in-well oxygenation events, can lead to erroneous iron concentrations. Lithologic and chemical heterogeneity and sampler placement depth can lead to differences between concentrations from diffusion samples and low-flow samples because of mixing during pumping. A disadvantage of regenerated cellulose dialysis samplers is that they can begin to biodegrade within the two weeks of deployment. Nylon-screen samplers buried beneath streambed sediment along the unnamed tributary in a discharge zone of arseniccontaminated ground water were useful in locating the specific discharge zone.

  18. Organic-inorganic hybrid gels for the selective absorption of oils from water.

    PubMed

    Ozan Aydin, Gulsah; Bulbul Sonmez, Hayal

    2016-06-01

    Organic-inorganic hybrid gels were synthesized by the condensation of a linear aliphatic diol (1,8-octanediol) and altering the chain length of the alkyltriethoxysilanes (from ethyltriethoxysilane to hexadecyltrimethoxysilane) through a bulk polymerization process without using any initiator, activator, catalyst, or solvent for the selective removal of oils from water. Fourier transform infrared spectroscopy (FTIR) and solid-state (13)C and (29)Si cross-polarization magic-angle spinning nuclear magnetic resonance (CPMAS NMR) were used for the structural analysis of hybrid gels. Thermal properties of the hybrid gels were determined by thermogravimetric analysis (TGA). Oil absorbency of organic-inorganic hybrid gels was determined by oil absorption tests. The results showed that hybrid gels have high and fast absorption capacities and excellent reusability. Good selectivity, high thermal stability, low density, and excellent recyclability for the oil removal give the material potential applications. PMID:26939691

  19. Transient streaming potentials under varying pore-water ionic strength

    NASA Astrophysics Data System (ADS)

    Malama, B.

    2014-12-01

    Streaming potentials (SP) are generated when polar fluids such as groundwater flow through porous media that have charged mineral surfaces. This is due to the flow-shearing of the diffuse layer of the electric double layer (EDL), which is known to form in the fluid phase at the fluid-rock interface. Previous works have suggested that the EDL vanishes at high pore-fluid ionic strengths resulting in vanishing SP signals. However, recent observations in sea-water intrusion applications by Jackson and coworkers indicate that measurable SP signals are obtainable in flows of fluids with high ionic strengths through silica sand. We demonstrate the repeatability of these observations through a series of laboratory flow experiments performed on 98% silica sand in a falling-head permeameter with brines of concentrations ranging from 0.001M to about 5 M NaCl. The results of the experiments, which clearly show measurable SP signals even at the highest concentration of 5 M NaCl, are reported. They are also used to estimate the hydraulic conductivity and electrokinetic coupling coefficient. The linearity assumption for the relation between pressure and SP differentials is evaluated for high pore-water NaCl concentrations. Additionally, displacement of one brine by another of different NaCl concentration yields dramatic transient SP responses that may be harnessed in the development of early-detection/warning technologies for sea-water intrusion applications. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S Department of Energy.

  20. Nanowire-haired inorganic membranes with superhydrophilicity and underwater ultralow adhesive superoleophobicity for high-efficiency oil/water separation.

    PubMed

    Zhang, Feng; Zhang, Wen Bin; Shi, Zhun; Wang, Dong; Jin, Jian; Jiang, Lei

    2013-08-14

    A novel all-inorganic Cu(OH)2 nanowire-haired membrane with superhydrophilicity and underwater ultralow adhesive superoleophobicity is fabricated by a facile surface oxidation of copper mesh that allows effective separation of both immiscible oil/water mixtures and oil-in-water emulsions solely driven by gravity, with extremely high separation efficiency. The all-inorganic membrane exhibits superior solvent and alkaline resistance and antifouling property compared to organic-based membranes. PMID:23788392

  1. Water temperature variability within an Arctic stream; analysis and implications

    NASA Astrophysics Data System (ADS)

    Mellor, C. J.; Hannah, D. M.; Milner, A. M.

    2009-04-01

    Arctic climate warming occurred at twice the global average over the last century and air temperature is predicted to increase by 7.5°C by 2099. Arctic river systems are hypothesized to be particularly vulnerable to warming due to their dependence on cryospheric water sources and thermal sensitivity of biotic communities. However, research is very limited on hydroecological response of Arctic rivers to a changing climate. This paper addresses this research gap and aims to investigate links between thermal dynamics and benthic communities for a river basin in Swedish Lappland. The Kårsavagge is located ~200 km north of the Arctic Circle and contains a small temperate glacier and two lakes. The Kårsa River drains into the Abisko River (~ 25 km from the valley head). The region experiences marked seasonality with average monthly air temperature ranging from +10 to -10°C. In June 2008, three gauging stations (1 - close to glacier snout, 2 - above first major extra glacial tributary and 3 - between the lakes and confluence with the Abisko river) were installed to record water temperature, riverbed temperature (at 0.05m, 0.20m and 0.40m depth), electrical conductivity, river stage, precipitation and turbidity. On top of these, twenty loggers recorded water temperature between gauging stations and across a braided reach located ~ 1.5km downstream of the glacier snout. Diurnal water temperature cycles were found at all sites; but average temperature increased downstream from 1.7°C near the glacier snout to 10.6°C before the Abisko River confluence. Sites immediately downstream of the lakes displayed moderated thermal variability. Bed temperatures in the upper catchment (lower) were higher (lower) and less variable that temperatures in the overlying water column. The degree of parity between water column and stream bed temperatures varied among sites with site 3 showing the greatest difference and site 2 showing the least. This implies a variable degree of

  2. Climate change and water conservation effects on water availability and vegetation patterns in a stream valley

    NASA Astrophysics Data System (ADS)

    van der Knaap, Yasmijn; de Graaf, Myrjam; van Ek, Remco; Witte, Jan-Philip; Aerts, Rien; Bierkens, Marc; van Bodegom, Peter

    2014-05-01

    Climate change predictions include an increase in global temperature and changes in precipitation patterns at spatial and seasonal scale. The seasonal changes for temperate Europe include a decrease in the amount of precipitation in summer and an increase in winter. This may lead to an increased flooding risk in winter and early spring, while in summer the drought risk is likely to increase. These hydrological changes can have profound effects on vegetation patterns and development, especially for groundwater dependent vegetation. Water conservation measures can be used to combat the potential negative effects of these changes. Conservation measures can include aquifer storage and recovery, damming streams, or creating retention zones for flooding events. The implementation of these measures can contribute to preserving groundwater dependent vegetation patterns. In this study we simulated with an integrated surface- and groundwater model and a climate robust vegetation model, the implementation of water conservation measures in a stream valley catchment in the Netherlands. We modeled the effects on water availability and on vegetation patterns. The conservation measures were simulated for the current climate and for two climate scenarios, with a temperature increase of two degrees Celsius and either an increase or decrease in precipitation. Water tables were increased in stream valley zones, where groundwater dependent vegetation dominates, to ensure suitable abiotic conditions. The results showed that the water conservation measures increased the water table considerably in a future climate, compared to no conservation measures. Groundwater dependent vegetation was positively stimulated with these new hydrological conditions. With these models we successfully tested the effectiveness of the water conservation measures on water availability and vegetation patterns to ameliorate the negative effects of climate change. We therefore argue that water conservation

  3. Air - water temperature relationships in the trout streams of southeastern Minnesota’s carbonate - sandstone landscape

    USGS Publications Warehouse

    Krider, Lori A.; Magner, Joseph A.; Perry, Jim; Vondracek, Bruce C.; Ferrington, Leonard C., Jr.

    2013-01-01

    Carbonate-sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface-water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater-fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air-water temperature relationships for 40 GWFS in southeastern Minnesota. A 40-stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface-water dominated streams. Regression models for streams with high R2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater-fed systems, but will do so at a slower rate than surface-water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.

  4. STREAM CORRIDOR RESTORATION AND ITS POTENTIAL TO IMPROVE WATER QUALITY

    EPA Science Inventory

    Watershed stream corridors are being degraded by anthropogenic impacts of increased flow from runoff, sediment loading from erosion and contaminants such as nitrate from non-point sources. One solution is to restore stream corridors with bank stabilization and energy dissipation ...

  5. A Practical Guide to Water Quality Studies of Streams.

    ERIC Educational Resources Information Center

    Kittrell, F. W.

    Reported are sampling methods that may be followed when performing stream studies. Sources of error and methods of their minimization are discussed. Because there is much variation within and between streams it is not possible to provide detailed definitive methods but alternatives are discussed. The selection of sampling sites and sampling…

  6. Organic and inorganic nitrogen pools in talus fields and subtalus water, Green Lakes Valley, Colorado front range

    USGS Publications Warehouse

    Williams, M.W.; Davinroy, T.; Brooks, P.D.

    1997-01-01

    Organic and inorganic pools of nitrogen (N) were measured in talus fines or 'soils' and subtalus water during the summer of 1995 in the alpine Green Lakes Valley catchment of the Colorado Front Range. Nineteen talus soil samples were divided into four classes: subtalus dry, subtalus wet, surface vegetated and surface bare. The size of the individual talus soil patches ranged from 0.5 to 12.0 m2 in area, with bulk density ranging from 0-98 to 1-71 kg m-3 and soil texture ranging from sandy gravel in the subsurface talus to a loam in the vegetated surface. All samples contained KCl-extractable NH4+ and NO3-, organic N and carbon (C), and 17 of 19 samples contained microbial biomass. The mean subtalus values for KCl-extractable NH4-, of 3.2 mg N kg-1, and NO3-, of 1.0 mg N kg-1, were comparable with developed alpine soils on Niwot Ridge. Average microbial biomass in subtalus soils of 5.4 mg N kg-1 and total N of 1000 mg N kg-1 were about an order of magnitude lower than alpine tundra soils, reflecting the reduced amount of vegetation in talus areas. However, these measurements in surface-vegetated patches of talus were comparable with the well-developed soils on Niwot Ridge. These measurements in talus of microbial biomass, total N and KCl-extractable NH4+ and NO3-, show that there is sufficient biotically conditioned 'soil' within talus fields to influence the solute content of interstitial waters. Mean NO3- concentrations of 20 ??eq 1-1 from 29 samples of subtalus water were significantly higher than the 6-7 ??eq 1-1 in snow, while NH4+ concentrations in subtalus water of 0??7 ??eq 1-1 was significantly lower than in snow at 5??2 ??eq 1-1 (p = 0??001). Nitrate concentrations in subtalus water were significantly (p < 0??0001) correlated with concentrations of geochemica??l weathering products such as Ca2+ (r2 = 0??84) and silica (r2 = 0??49). The correlation of NO3- in subtalus water with geochemical weathering products suggests that NO3- concentrations in subtalus

  7. Influence of Land Use on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Georgia Piedmont Headwater Streams

    EPA Science Inventory

    Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important...

  8. Impact of Mountaintop Mining/Valley Fill on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Headwater Streams

    EPA Science Inventory

    Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important...

  9. Dry Stream Reaches in Carbonate Terranes: Surface Indicators of Ground-Water Reservoirs

    USGS Publications Warehouse

    Brahana, J.V.; Hollyday, E.F.

    1988-01-01

    In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet-like dissolution openings have developed parallel to bedding creating the ground-water reservoir. Union Hollow in south-central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: remotely sensed black and white infrared aerial photography; and surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground-water reservoir was present.

  10. Estimation of upstream water use with Ohio’s StreamStats application

    USGS Publications Warehouse

    Koltun, G.F.; Nardi, Mark R.; Shaffer, Kimberly H.

    2016-01-01

    Temporary water-use registrations for hydraulic fracturing are tabulated separately from the other water uses. Water-use indices are computed by dividing average annual net withdrawals (with and without temporary registrations) by the mean October streamflow estimated with StreamStats. The water-use indices are intended to provide metrics of potential consumptive water use.

  11. Facile fabrication of organic/inorganic nanotube heterojunction arrays for enhanced photoelectrochemical water splitting

    NASA Astrophysics Data System (ADS)

    Chen, Yingzhi; Li, Aoxiang; Yue, Xiaoqi; Wang, Lu-Ning; Huang, Zheng-Hong; Kang, Feiyu; Volinsky, Alex A.

    2016-07-01

    Organic/inorganic heterojunction photoanodes are appealing for making concurrent use of the highly photoactive organic semiconductors, and the efficient dielectric screening provided by their inorganic counterparts. In the present work, organic/inorganic nanotube heterojunction arrays composed of TiO2 nanotube arrays and a semiconducting N,N-(dicyclohexyl) perylene-3,4,9,10-tetracarboxylic diimide (PDi) layer were fabricated for photoelectrochemical water splitting. In this arrayed architecture, a PDi layer with a tunable thickness was coated on anodic TiO2 nanotube arrays by physical vapor deposition, which is advantageous for the formation of a uniform layer and an adequate interface contact between PDi and TiO2. The obtained PDi/TiO2 junction exhibited broadened visible light absorption, and an effective interface for enhanced photogenerated electron-hole separation, which is supported by the reduced charge transfer resistance and prolonged excitation lifetime via impedance spectroscopy analysis and fluorescence emission decay investigations. Consequently, such a heterojunction photoanode was photoresponsive to a wide visible light region of 400-600 nm, and thus demonstrated a highly enhanced photocurrent density at 1.23 V vs. a reversible hydrogen electrode. Additionally, the durability of such a photoanode can be guaranteed after long-time illumination because of the geometrical restraint imposed by the PDi aggregates. These results pave the way to discover new organic/inorganic assemblies for high-performance photoelectric applications and device integration.Organic/inorganic heterojunction photoanodes are appealing for making concurrent use of the highly photoactive organic semiconductors, and the efficient dielectric screening provided by their inorganic counterparts. In the present work, organic/inorganic nanotube heterojunction arrays composed of TiO2 nanotube arrays and a semiconducting N,N-(dicyclohexyl) perylene-3,4,9,10-tetracarboxylic diimide (PDi

  12. Spatiotemporal dynamics of spring and stream water chemistry in a high-mountain area.

    PubMed

    Zelazny, Mirosław; Astel, Aleksander; Wolanin, Anna; Małek, Stanisław

    2011-05-01

    The present study deals with the application of the self-organizing map (SOM) technique in the exploration of spatiotemporal dynamics of spring and stream water samples collected in the Chochołowski Stream Basin located in the Tatra Mountains (Poland). The SOM-based classification helped to uncover relationships between physical and chemical parameters of water samples and factors determining the quality of water in the studied high-mountain area. In the upper part of the Chochołowski Stream Basin, located on the top of the crystalline core of the Tatras, concentrations of the majority of ionic substances were the lowest due to limited leaching. Significantly higher concentration of ionic substances was detected in spring and stream samples draining sedimentary rocks. The influence of karst-type springs on the quality of stream water was also demonstrated. PMID:21168942

  13. Rapid Reduction in Breast Cancer Mortality With Inorganic Arsenic in Drinking Water

    PubMed Central

    Smith, Allan H.; Marshall, Guillermo; Yuan, Yan; Steinmaus, Craig; Liaw, Jane; Smith, Martyn T.; Wood, Lily; Heirich, Marissa; Fritzemeier, Rebecca M.; Pegram, Mark D.; Ferreccio, Catterina

    2014-01-01

    Background Arsenic trioxide is effective in treating promyelocytic leukemia, and laboratory studies demonstrate that arsenic trioxide causes apoptosis of human breast cancer cells. Region II in northern Chile experienced very high concentrations of inorganic arsenic in drinking water, especially in the main city Antofagasta from 1958 until an arsenic removal plant was installed in 1970. Methods We investigated breast cancer mortality from 1950 to 2010 among women in Region II compared to Region V, which had low arsenic water concentrations. We conducted studies on human breast cancer cell lines and compared arsenic exposure in Antofagasta with concentrations inducing apoptosis in laboratory studies. Findings Before 1958, breast cancer mortality rates were similar, but in 1958–1970 the rates in Region II were half those in Region V (rate ratio RR = 0.51, 95% CI 0.40–0.66; p < 0.0001). Women under the age of 60 experienced a 70% reduction in breast cancer mortality during 1965–1970 (RR = 0.30, 0.17–0.54; p < 0.0001). Breast cancer cell culture studies showed apoptosis at arsenic concentrations close to those estimated to have occurred in people in Region II. Interpretation We found biologically plausible major reductions in breast cancer mortality during high exposure to inorganic arsenic in drinking water which could not be attributed to bias or confounding. We recommend clinical trial assessment of inorganic arsenic in the treatment of advanced breast cancer. PMID:25580451

  14. Bacterial pathogens in Hawaiian coastal streams--associations with fecal indicators, land cover, and water quality.

    PubMed

    Viau, Emily J; Goodwin, Kelly D; Yamahara, Kevan M; Layton, Blythe A; Sassoubre, Lauren M; Burns, Siobhán L; Tong, Hsin-I; Wong, Simon H C; Lu, Yuanan; Boehm, Alexandria B

    2011-05-01

    This work aimed to understand the distribution of five bacterial pathogens in O'ahu coastal streams and relate their presence to microbial indicator concentrations, land cover of the surrounding watersheds, and physical-chemical measures of stream water quality. Twenty-two streams were sampled four times (in December and March, before sunrise and at high noon) to capture seasonal and time of day variation. Salmonella, Campylobacter, Staphylococcus aureus, Vibrio vulnificus, and V. parahaemolyticus were widespread -12 of 22 O'ahu streams had all five pathogens. All stream waters also had detectable concentrations of four fecal indicators and total vibrio with log mean ± standard deviation densities of 2.2 ± 0.8 enterococci, 2.7 ± 0.7 Escherichia coli, 1.1 ± 0.7 Clostridium perfringens, 1.2 ± 0.8 F(+) coliphages, and 3.6 ± 0.7 total vibrio per 100 ml. Bivariate associations between pathogens and indicators showed enterococci positively associated with the greatest number of bacterial pathogens. Higher concentrations of enterococci and higher incidence of Campylobacter were found in stream waters collected before sunrise, suggesting these organisms are sensitive to sunlight. Multivariate regression models of microbes as a function of land cover and physical-chemical water quality showed positive associations between Salmonella and agricultural and forested land covers, and between S. aureus and urban and agricultural land covers; these results suggested that sources specific to those land covers may contribute these pathogens to streams. Further, significant associations between some microbial targets and physical-chemical stream water quality (i.e., temperature, nutrients, turbidity) suggested that organism persistence may be affected by stream characteristics. Results implicate streams as a source of pathogens to coastal waters. Future work is recommended to determine infectious risks of recreational waterborne illness related to O'ahu stream exposures and to

  15. Photolysis of inorganic chloramines and efficiency of trichloramine abatement by UV treatment of swimming pool water.

    PubMed

    Soltermann, Fabian; Widler, Tobias; Canonica, Silvio; von Gunten, Urs

    2014-06-01

    Trichloramine, one of the three inorganic chloramines (mono-, di- and trichloramine), is a problematic disinfection by-product in recreational pool water since it causes skin and eye irritations as well as irritations of the respiratory tract. The most commonly used chloramine mitigation strategy in pool water is UV treatment. Experiments with membrane inlet mass spectrometry (MIMS) confirmed that inorganic chloramines are effectively degraded by UV irradiation with low-pressure (LP) and medium-pressure (MP) mercury lamps (apparent quantum yields (QY): NH2Cl = 0.50 (LP) and 0.31 (MP) mol einstein(-1), NHCl2: 1.06 (LP) and 0.85 (MP) mol einstein(-1)). Trichloramine showed the fastest depletion with a quantum yield slightly above 2 mol einstein(-1) in purified (LP and MP) and pool water (MP). This high quantum yield can partly be explained by reactions involving OH radicals (purified water) and the reaction of trichloramine with moieties formed during UV irradiation of pool water. The presence of free chlorine affects trichloramine degradation (QY: ∼1.5 mol einstein(-1)) since it scavenges OH radicals and competes with trichloramine for reactive species (e.g. organic amines). Measurements in a pool facility revealed that the installed UV reactors degraded trichloramine by 40-50% as expected from laboratory experiments. However, trichloramine reduction in the pools was less pronounced than in the UV reactors. Model calculations combining pool hydraulics with formation/abatement of trichloramine showed that there was a fast trichloramine formation in the pool from the residual chlorine and nitrogenous precursors. The main factors influencing trichloramine concentrations in pool water are the free chlorine concentration and the UV treatment in combination with the recirculation rate through the water treatment system. PMID:24699420

  16. The influence of industrial and agricultural waste on water quality in the Água Boa stream (Dourados, Mato Grosso do Sul, Brazil).

    PubMed

    da Rocha, Monyque Palagano; Dourado, Priscila Leocadia Rosa; de Souza Rodrigues, Mayara; Raposo, Jorge Luiz; Grisolia, Alexeia Barufatti; de Oliveira, Kelly Mari Pires

    2015-07-01

    Water quality monitoring is used to determine the impact of human activities on the environment. We evaluated water quality in the Água Boa stream, located within the municipality of Dourados, State of Mato Grosso do Sul, Brazil, by analyzing physico-chemical, chemical, and microbiological parameters, as well as chlorophyll concentrations. Five sets of water samples were collected between December 2012 and November 2013 from three locations within the stream. The results showed the presence of Escherichia coli and antibiotic-resistant Pseudomonas spp. strains and high concentrations of organic matter (total dissolved solids), inorganic species (Mg, Ca, and Fe), and agrochemical residues (thiamethoxam). The main stream water contaminants are derived from urban, industrial, and agricultural activities within the watershed. Given the presence of contaminants, it is important that such findings are disseminated in order to highlight the risks that contact with this water may pose to human health. To preserve the environment and improve site conditions, people would need to participate by demanding that normative national and international standards be respected and that the situation be supervised by the competent governmental agencies; this would make it possible to reverse or minimize contamination problems within the Água Boa stream. PMID:26088756

  17. Urinary arsenic profiles reveal exposures to inorganic arsenic from private drinking water supplies in Cornwall, UK

    PubMed Central

    Middleton, D. R. S.; Watts, M. J.; Hamilton, E. M.; Ander, E. L.; Close, R. M.; Exley, K. S.; Crabbe, H.; Leonardi, G. S.; Fletcher, T.; Polya, D. A.

    2016-01-01

    Private water supplies (PWS) in Cornwall, South West England exceeded the current WHO guidance value and UK prescribed concentration or value (PCV) for arsenic of 10 μg/L in 5% of properties surveyed (n = 497). In this follow-up study, the first of its kind in the UK, volunteers (n = 207) from 127 households who used their PWS for drinking, provided urine and drinking water samples for total As determination by inductively coupled plasma mass spectrometry (ICP-MS) and urinary As speciation by high performance liquid chromatography ICP-MS (HPLC-ICP-MS). Arsenic concentrations exceeding 10 μg/L were found in the PWS of 10% of the volunteers. Unadjusted total urinary As concentrations were poorly correlated (Spearman’s ρ = 0.36 (P < 0.001)) with PWS As largely due to the use of spot urine samples and the dominance of arsenobetaine (AB) from seafood sources. However, the osmolality adjusted sum, U-AsIMM, of urinary inorganic As species, arsenite (AsIII) and arsenate (AsV), and their metabolites, methylarsonate (MA) and dimethylarsinate (DMA), was found to strongly correlate (Spearman’s ρ: 0.62 (P < 0.001)) with PWS As, indicating private water supplies as the dominant source of inorganic As exposure in the study population of PWS users. PMID:27156998

  18. Urinary arsenic profiles reveal exposures to inorganic arsenic from private drinking water supplies in Cornwall, UK

    NASA Astrophysics Data System (ADS)

    Middleton, D. R. S.; Watts, M. J.; Hamilton, E. M.; Ander, E. L.; Close, R. M.; Exley, K. S.; Crabbe, H.; Leonardi, G. S.; Fletcher, T.; Polya, D. A.

    2016-05-01

    Private water supplies (PWS) in Cornwall, South West England exceeded the current WHO guidance value and UK prescribed concentration or value (PCV) for arsenic of 10 μg/L in 5% of properties surveyed (n = 497). In this follow-up study, the first of its kind in the UK, volunteers (n = 207) from 127 households who used their PWS for drinking, provided urine and drinking water samples for total As determination by inductively coupled plasma mass spectrometry (ICP-MS) and urinary As speciation by high performance liquid chromatography ICP-MS (HPLC-ICP-MS). Arsenic concentrations exceeding 10 μg/L were found in the PWS of 10% of the volunteers. Unadjusted total urinary As concentrations were poorly correlated (Spearman’s ρ = 0.36 (P < 0.001)) with PWS As largely due to the use of spot urine samples and the dominance of arsenobetaine (AB) from seafood sources. However, the osmolality adjusted sum, U-AsIMM, of urinary inorganic As species, arsenite (AsIII) and arsenate (AsV), and their metabolites, methylarsonate (MA) and dimethylarsinate (DMA), was found to strongly correlate (Spearman’s ρ: 0.62 (P < 0.001)) with PWS As, indicating private water supplies as the dominant source of inorganic As exposure in the study population of PWS users.

  19. Inorganic mesoporous membranes for water purification applications: Synthesis, testing and modeling

    NASA Astrophysics Data System (ADS)

    Yu, Di

    Inorganic mesoporous membranes showed potential for water purification and desalinization by nanofiltration. In this work, a composite mesoporous inorganic membrane was synthesized with a two layer structure. The supporting layer was a macroporous alpha-Al 2O3 substrate prepared with the colloidal filtration technique. The functional layer was a mesoporous gamma-alumina thin film prepared with the sol-gel method. The synthesis of each layer was systematically studied and carefully optimized to obtain defect free membranes. The membrane device was then tested with a homemade water pressurization chamber under various experimental conditions to systematically characterize the water purification performance of the membrane. The experiments determined limiting salt rejection at various testing conditions. The purification behavior was studied for three types of electrolyte aqueous solutions, NaCl, CaCl 2 and AlCl3 at a concentration range from 0.001 M to 0.1 M. A model based on surface charge adsorption and electrokinetic mass transportation was established with commercial FEM modeling software, COMSOL 3.2b, to study the purification mechanism and the performance limitations. Qualitative agreement between the experiment and the modeling results was obtained.

  20. Water uptake of multicomponent organic mixtures and their influence on hygroscopicity of inorganic salts.

    PubMed

    Wang, Yuanyuan; Jing, Bo; Guo, Yucong; Li, Junling; Tong, Shengrui; Zhang, Yunhong; Ge, Maofa

    2016-07-01

    The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds (WSOCs) and their effects on ammonium sulfate (AS) and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer (HTDMA) in the relative humidity (RH) range of 5%-90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model (E-AIM) and Zdanovskii-Stokes-Robinson (ZSR) method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles. When organic content was dominant in the mixture (75%), the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles. PMID:27372129

  1. Dissolved inorganic carbon isotopic composition of the Gulf of Mexico deep-water masses.

    NASA Astrophysics Data System (ADS)

    Quintanilla-Terminel, J. G.; Herguera, J. C.; Ferreira-Bartrina, V.; Hernández-Ayón, J. M.; Camacho-Ibar, V.

    2014-12-01

    This study provides new data for the establishment of a carbon biogeochemical dynamics baseline in the deep Gulf of Mexico (GM) based on carbon isotopes in dissolved inorganic carbon. Water samples from 40 deep-water stations south of 25˚N were collected during XIXIMI-2 cruise, July 2011, aboard BO/Justo Sierra. Vertical profiles of temperature, salinity and dissolved oxygen (DO) were further measured in each station. In the Stable Isotopes Laboratory at CICESE we determined the carbon isotopic composition of the dissolved inorganic carbon (DIC) (δ13CDIC). Remarkably, density, DO and δ13CCID profiles showed a clear difference between the Loop current and the deep-waters of the GM south of 25˚N. We found the following average δ13CCID values in the Loop current and in the deep-waters of the Gulf: subtropical underwater (SUW): 0.73±0.06‰ and 0.86±0.04‰; 18 degree water (18W): 0.76 ± 0.08‰ and 0.58± 0.06‰; North Atlantic central water (NACW): 0.77 ± 0.05‰ and 0.71 ± 0.09‰; South Atlantic central water (SACW): 0.80 ± 0.08‰ and 0.77 ± 0.07‰; Antartic intermediate water (AAIW): 1.00 ± 0.06‰ and 0.90 ± 0.08‰; North Atlantic deep water (NADW): 1.03 ± 0.06‰ and 1.01 ± 0.10‰. We will discuss how the biological component, δ13CCID-BIO, of subsurface water masses match very closely the apparent oxygen utilization relation described by Kroopnick, 1985, with the exception of SUW, and as a consequence the 18W is probably the water mass most affected by organic carbon remineralization processes in the GM south of 25˚N. We further show how these waters seem to store a larger proportion of anthropogenic carbon than the deeper water masses.

  2. Long-term mortality patterns in a residential cohort exposed to inorganic selenium in drinking water.

    PubMed

    Vinceti, Marco; Ballotari, Paola; Steinmaus, Craig; Malagoli, Carlotta; Luberto, Ferdinando; Malavolti, Marcella; Giorgi Rossi, Paolo

    2016-10-01

    Selenium (Se) is a metalloid of considerable nutritional and toxicological importance in humans. To date, limited epidemiologic evidence exists about the health effects of exposure to this trace element in drinking water. We investigated the relationship between Se levels in water and mortality in the municipality of Reggio Emilia, Italy, where high levels of Se were previously observed in drinking water. From 1974 to 1985, 2065 residents consumed drinking water with Se levels close to the European standard of 10μg/l, in its inorganic hexavalent form (selenate). Follow-up was conducted for the years 1986-2012 in Reggio Emilia and a lesser exposed comparison group of around 100,000 municipal residents, with comparable socio-demographic characteristics. Overall mortality from all causes, cardiovascular disease and cancer showed little evidence of differences. However, excess rate ratios were seen for some site specific cancers such as neoplasms of buccal cavity and pharynx, urinary tract, lymphohematopoietic tissue, melanoma, and two neurodegenerative diseases, Parkinson's disease and amyotrophic lateral sclerosis. Excess mortality in the exposed cohort for specific outcomes was concentrated in the first period of follow-up (1986-1997), and waned starting 10 years after the high exposure ended. We also found lower mortality from breast cancer in females during the first period of follow-up. When we extended the analysis to include residents who had been consuming the high-selenium drinking water for a shorter period, mortality rate ratios were also increased, but to a lesser extent. Overall, we found that the mortality patterns related to long-term exposure to inorganic hexavalent selenium through drinking water were elevated for several site-specific cancers and neurodegenerative disease. PMID:27344266

  3. Effects of urbanization on stream water quality in the city of Atlanta, Georgia, USA

    USGS Publications Warehouse

    Peters, N.E.

    2009-01-01

    A long-term stream water quality monitoring network was established in the city of Atlanta, Georgia during 2003 to assess baseline water quality conditions and the effects of urbanization on stream water quality. Routine hydrologically based manual stream sampling, including several concurrent manual point and equal width increment sampling, was conducted ???12 times annually at 21 stations, with drainage areas ranging from 3.7 to 232 km2. Eleven of the stations are real-time (RT) stations having continuous measures of stream stage/ discharge, pH, dissolved oxygen, specific conductance, water temperature and turbidity, and automatic samplers for stormwater collection. Samples were analyzed for field parameters, and a broad suite of water quality and sediment-related constituents. Field parameters and concentrations of major ions, metals, nutrient species and coliform bacteria among stations were evaluated and with respect to watershed characteristics and plausible sources from 2003 through September 2007. Most constituent concentrations are much higher than nearby reference streams. Concentrations are statistically different among stations for several constituents, despite high variability both within and among stations. Routine manual sampling, automatic sampling during stormflows and RT water quality monitoring provided sufficient information about urban stream water quality variability to evaluate causes of water quality differences among streams. Fecal coliform bacteria concentrations of most samples exceeded Georgia's water quality standard for any water-usage class. High chloride concentrations occur at three stations and are hypothesized to be associated with discharges of chlorinated combined sewer overflows, drainage of swimming pool(s) and dissolution and transport during rainstorms of CaCl2, a deicing salt applied to roads during winter storms. One stream was affected by dissolution and transport of ammonium alum [NH4Al(SO4)2] from an alum

  4. Impacts of groundwater metal loads from bedrock fractures on water quality of a mountain stream.

    PubMed

    Caruso, Brian S; Dawson, Helen E

    2009-06-01

    Acid mine drainage and metal loads from hardrock mines to surface waters is a significant problem in the western USA and many parts of the world. Mines often occur in mountain environments with fractured bedrock aquifers that serve as pathways for metals transport to streams. This study evaluates impacts from current and potential future groundwater metal (Cd, Cu, and Zn) loads from fractures underlying the Gilt Edge Mine, South Dakota, on concentrations in Strawberry Creek using existing flow and water quality data and simple mixing/dilution mass balance models. Results showed that metal loads from bedrock fractures to the creek currently contribute <1% of total loads. Even if background water quality is achieved upstream in Strawberry Creek, fracture metal loads would be <5%. Fracture loads could increase substantially and cause stream water quality standards exceedances once groundwater with elevated metals concentrations in the aquifer matrix migrates to the fractures and discharges to the stream. Potential future metal loads from an upstream fracture would contribute a small proportion of the total load relative to current loads in the stream. Cd has the highest stream concentrations relative to standards. Even if all stream water was treated to remove 90% of the Cd, the standard would still not be achieved. At a fracture farther downstream, the Cd standard can only be met if the upstream water is treated achieving a 90% reduction in Cd concentrations and the median stream flow is maintained. PMID:18604589

  5. Stream Hydrology and Water Quality Impacts of Contrasting Urban Stormwater Mitigation Strategies: Centralized Versus Distributed

    EPA Science Inventory

    Urban land cover is commonly associated with degraded stream habitat including flashier hydrology, increased pollutant export, and lower ecological health , collectively termed “urban stream syndrome.” Pollutant export from urban areas can also contribute to water quality issues...

  6. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    NASA Astrophysics Data System (ADS)

    Lyon, S. W.; Seibert, J.; Lembo, A. J.; Steenhuis, T. S.; Walter, M. T.

    2008-06-01

    Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State). Three distance definitions (or metrics) were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  7. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    NASA Astrophysics Data System (ADS)

    Lyon, S. W.; Seibert, J.; Lembo, A. J.; Steenhuis, T. S.; Walter, M. T.

    2008-10-01

    Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State). Three distance definitions (or metrics) were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  8. MAPPING DYNAMIC STREAM NETWORKS AND ASSESSING THEIR SIGNIFICANCE ON WATER QUALITY

    EPA Science Inventory

    Little is known about how active stream network expansion during rainstorms influences the ability of riparian buffers to improve water quality. We used aerial photographs to quantify stream network expansion during the wet winter season in five mixed land-use watersheds in west...

  9. Mixing Hot and Cold Water Streams at a T-Junction

    ERIC Educational Resources Information Center

    Sharp, David; Zhang, Mingqian; Xu, Zhenghe; Ryan, Jim; Wanke, Sieghard; Afacan, Artin

    2008-01-01

    A simple mixing of a hot- and cold-water stream at a T-junction was investigated. The main objective was to use mass and energy balance equations to predict mass low rates and the temperature of the mixed stream after the T-junction, and then compare these with the measured values. Furthermore, the thermocouple location after the T-junction and…

  10. Stream water quality in the context of payments for environmental services in Southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Piccolo, M. C.; Reis, L. D. C.; Figueiredo, R. D. O.; Camargo, P. B. D.; Costa, C. F. G. D.; Zuccari, M. L.; Green, T. R.

    2015-12-01

    Public policy of payment for environmental services (PES) was established in 2007 to face the challenge of recuperatingwater resources at one of the headwater areas of the Jaguari River Basin, which supplies an important reservoir for the metropolitan region of São Paulo, Brazil. Such effort consists of reforestation of riparian zones and spring lands at the hills of selected catchments, including the Ribeirão das Posses (RP) catchment. Since 2012 the University of São Paulo has developed research at RP to monitor the benefits of these practices on stream water quality, and identified a few parameters as good indicators to follow up the results of this PES program. The present study has the objective to show results of the monthly monitoring in2015,including 13 sampling stations at RP catchment distributed as follows: one in a spring forested area, three in spring areas of different ages of reforestation (3, 5 and 8 years), and nine at reaches of RP streamlocated in a way to contemplate the effects of the first order streams that comes from the studied spring areas entering RP. We established two additional stations at the Jaguari River, upstream and downstream of RP outlet. In situ measurements include temperature, pH, electric conductivity (EC) and dissolved oxygen (DO), and collect water samples to bring to the laboratory for analyses of dissolved organic and inorganic carbon (DOC and DIC), total nitrogen (TN) and alkalinity. Also, sediments (fine fraction: >0.45 μm; and coarse fraction: >63 μm) are collected for isotopic carbon analyses. Preliminary results show pH values ranging from 5.5 to 7.8, while DO ranges from 5.8 to 8.9 mg L-1. As for EC, the mean at the spring forested station was 34.6 μS cm-1, while at spring areas of 3, 6 and 8 years of reforestation they were 53.3, 73.8 and 34.8 μS cm-1, respectively. We expected that by the end of this annual monitoring the benefits of reforestation will be affirmed.

  11. Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle

    NASA Technical Reports Server (NTRS)

    Fuerstenau, D. W.; Huang, P.; Ravikumar, R.

    1997-01-01

    The objective of this research was two-fold: first, to identify and test inorganic water-repellent materials that would be hydrophobic even after thermal cycling to temperatures above 600 C and, second, to develop a model that would link hydrophobicity of a material to the chemical properties of its constituent atoms. Four different materials were selected for detailed experimental study, namely, boron nitride, talc, molybdenite, and pyrophyllite, all of which have a layered structure made up of ionic/covalent bonds within the layers but with van der Waals bonds between the layers. The materials tested could be considered hydrophobic for a nonporous surface but none of the observed contact angles exceeded the necessary 90 degrees required for water repellency of porous materials. Boron nitride and talc were observed to retain their water-repellency when heated in air to temperatures that did not exceed 800 C, and molybdenite was found to be retain its hydrophobicity when heated to temperatures up to 600 C. For these three materials, oxidation and decomposition were identified to be the main cause for the breakdown of water repellency after repeated thermal cycling. Pyrophyllite shows the maximum promise as a potential water-repellent inorganic material, which, when treated initially at 900 C, retained its shape and remained hydrophobic for two thermal cycles where the maximum retreatment temperature is 900 C. A model was developed for predicting materials that might exhibit hydrophobicity by linking two chemical properties, namely, that the constituent ions of the compound belong to the soft acid-base category and that the fractional ionic character of the bonds be less than about 20 percent.

  12. Geology, Streamflow, and Water Chemistry of the Talufofo Stream Basin, Saipan, Northern Mariana Islands

    USGS Publications Warehouse

    Izuka, Scot K.; Ewart, Charles J., III

    1995-01-01

    A study of the geology, streamflow, and water chemistry of Talufofo Stream Basin, Saipan, Commonwealth of the Northern Mariana Islands, was undertaken to determine the flow characteristics of Talufofo Stream and the relation to the geology of the drainage basin. The Commonwealth government is exploring the feasibility of using water from Talufofo Stream to supplement Saipan's stressed municipal water supply. Streamflow records from gaging stations on the principal forks of Talufofo Stream indicate that peak streamflows and long-term average flow are higher at the South Fork gaging station than at the Middle Fork gaging station because the drainage area of the South Fork gaging station is larger, but persistent base flow from ground-water discharge during dry weather is greater in the Middle Fork gaging station. The sum of the average flows at the Middle Fork and South Fork gaging stations, plus an estimate of the average flow at a point in the lower reaches of the North Fork, is about 2.96 cubic feet per second or 1.91 million gallons per day. Although this average represents the theoretical maximum long-term draft rate possible from the Talufofo Stream Basin if an adequate reservoir can be built, the actual amount of surface water available will be less because of evaporation, leaks, induced infiltration, and reservoir-design constraints. Base-flow characteristics, such as stream seepage and spring discharge, are related to geology of the basin. Base flow in the Talufofo Stream Basin originates as discharge from springs near the base of limestones located in the headwaters of Talufofo Stream, flows over low-permeability volcanic rocks in the middle reaches, and seeps back into the high-permeability limestones in the lower reaches. Water sampled from Talufofo Stream during base flow had high dissolved-calcium concentrations (between 35 and 98 milligrams per liter), characteristic of water from a limestone aquifer. Concentrations of potassium, sodium, and chloride

  13. Biomimetic artificial inorganic enzyme-free self-propelled microfish robot for selective detection of Pb(2+) in water.

    PubMed

    Moo, James Guo Sheng; Wang, Hong; Zhao, Guanjia; Pumera, Martin

    2014-04-01

    The availability of drinking water is of utmost importance for the world population. Anthropogenic pollutants of water, such as heavy-metal ions, are major problems in water contamination. The toxicity assays used range from cell assays to animal tests. Herein, we replace biological toxicity assays, which use higher organisms, with artificial inorganic self-propelled microtubular robots. The viability and activity of these robots are negatively influenced by heavy metals, such as Pb(2+) , in a similar manner to that of live fish models. This allows the establishment of a lethal dose (LD50 ) of heavy metal for artificial inorganic microfish robots. The self-propelled microfish robots show specific response to Pb(2+) compared to other heavy metals, such as Cd(2+) , and can be used for selective determination of Pb(2+) in water. It is a first step towards replacing the biological toxicity assays with biomimetic inorganic autonomous robotic systems. PMID:24652757

  14. Seasonal variations of dissolved inorganic carbon and δ13C of surface waters: application of a modified gas evolution technique

    NASA Astrophysics Data System (ADS)

    Atekwana, E. A.; Krishnamurthy, R. V.

    1998-03-01

    Seasonal concentrations and δ13C of dissolved inorganic carbon (DIC) in a river-tributary system in Kalamazoo, southwest Michigan, USA, have been measured using a modified gas evolution technique. The technique makes use of evacuated glass septum tubes pre-loaded with phosphoric acid and a magnetic stir bar. Water samples are injected into these septum tubes in the field, which eliminates problems associated with CO 2 loss/gain during sample storage and transfer to the vacuum line during DIC extraction. Using this technique, a precision of 1% and 0.1‰ can be achieved for DIC concentrations and δ13C DIC measurements, respectively. As this technique provides reliable measurements of DIC concentrations and carbon isotope ratios, it was used to evaluate the processes that control DIC in the river-tributary system. Results of DIC concentration and δ13C DIC measurements of water samples from the river-tributary system show that the DIC pool is mostly dominated by groundwater. The DIC concentrations and δ13C DIC are within the ranges measured for the most isotopically evolved groundwater in this region. Seasonal variations superimposed on the baseline values are attributed to secondary processes such as CO 2 invasion from the atmosphere, enhanced recharge from lakes and biological activities of photosynthesis, respiration, and decay. With the onset of spring, there is a concurrent increase in the DIC concentration and δ13C DIC of these streams. A simultaneous increase in concentration and 13C enrichment of the riverine DIC pool is consistent with CO 2 invasion and recharge from lakes. During the summer, biological activity is the predominant control on shifts in the DIC pool. Although photosynthesis, respiration and decay occur during this time, decreases in the DIC concentration and increases in the 13C DIC indicates CO 2 removal from the pool by photosynthesis. In the late summer-early fall, photosynthesis declines and respiration and decay cause an increase in

  15. Photosynthetic use of inorganic carbon in deep-water kelps from the Strait of Gibraltar.

    PubMed

    García-Sánchez, María Jesús; Delgado-Huertas, Antonio; Fernández, José Antonio; Flores-Moya, Antonio

    2016-03-01

    Mechanisms of inorganic carbon assimilation were investigated in the four deep-water kelps inhabiting sea bottoms at the Strait of Gibraltar; these species are distributed at different depths (Saccorhiza polysiches at shallower waters, followed by Laminaria ochroleuca, then Phyllariopsis brevipes and, at the deepest bottoms, Phyllariopsis purpurascens). To elucidate the capacity to use HCO3 (-) as a source of inorganic carbon for photosynthesis in the kelps, different experimental approaches were used. Specifically, we measured the irradiance-saturated gross photosynthetic rate versus pH at a constant dissolved inorganic carbon (DIC) concentration of 2 mM, the irradiance-saturated apparent photosynthesis (APS) rate versus DIC, the total and the extracellular carbonic anhydrase (CAext), the observed and the theoretical photosynthetic rates supported by the spontaneous dehydration of HCO3 (-) to CO2, and the δ(13)C signature in tissues of the algae. While S. polyschides and L. ochroleuca showed photosynthetic activity at pH 9.5 (around 1.0 µmol O2 m(-2) s(-1)), the activity was close to zero in both species of Phyllariopsis. The APS versus DIC was almost saturated for the DIC values of natural seawater (2 mM) in S. polyschides and L. ochroleuca, but the relationship was linear in P. brevipes and P. purpurascens. The four species showed total and CAext activities but the inhibition of the CAext originated the observed photosynthetic rates at pH 8.0 to be similar to the theoretical rates that could be supported by the spontaneous dehydration of HCO3 (-). The isotopic (13)C signatures ranged from -17.40 ± 1.81 to -21.11 ± 1.73 ‰ in the four species. Additionally, the δ(13)C signature was also measured in the deep-water Laminaria rodriguezii growing at 60-80 m, showing even a more negative value of -26.49 ± 1.25 ‰. All these results suggest that the four kelps can use HCO3 (-) as external carbon source for photosynthesis mainly by the action of

  16. Inorganic chemistry of water and bed sediment in selected tributaries of the south Umpqua River, Oregon, 1998

    USGS Publications Warehouse

    Hinkle, Stephen R.

    1999-01-01

    Ten sites on small South Umpqua River tributaries were sampled for inorganic constituents in water and streambed sediment. In aqueous samples, high concentrations (concentrations exceeding U.S. Environmental Protection Agency criterion continuous concentration for the protection of aquatic life) of zinc, copper, and cadmium were detected in Middle Creek at Silver Butte, and the concentration of zinc was high at Middle Creek near Riddle. Similar patterns of trace-element occurrence were observed in streambed-sediment samples.The dissolved aqueous load of zinc carried by Middle Creek along the stretch between the upper site (Middle Creek at Silver Butte) and the lower site (Middle Creek near Riddle) decreased by about 0.3 pounds per day. Removal of zinc from solution between the upper and lower sites on Middle Creek evidently was occurring at the time of sampling. However, zinc that leaves the aqueous phase is not necessarily permanently lost from solution. For example, zinc solubility is pH-dependent, and a shift between solid and aqueous phases towards release of zinc to solution in Middle Creek could occur with a perturbation in stream-water pH. Thus, at least two potentially significant sources of zinc may exist in Middle Creek: (1) the upstream source(s) producing the observed high aqueous zinc concentrations and (2) the streambed sediment itself (zinc-bearing solid phases and/or adsorbed zinc). Similar behavior may be exhibited by copper and cadmium because these trace elements also were present at high concentrations in streambed sediment in the Middle Creek Basin.

  17. DOM in stream water and soil solution in two small, bordering catchments in central Sweden

    NASA Astrophysics Data System (ADS)

    Norström, Sara H.; Bylund, Dan

    2013-04-01

    Seasonal variations in dissolved organic matter (DOM) and the influence of wood ash application on DOM were studied in two first order streams draining two small, bordering forested catchments. The catchments, 40 and 50 h respectively, were situated in Bispgården (63°07N, 16°70E), central Sweden with forest consisting of mainly 50 to 80 year-old Norway spruce (Picea abies) and Scots pine (Pinus sylvestris). Seasonal variations in the stream water were measured during 2003-2007, and wood ash was applied in one of the catchments in the fall of 2004. In addition to stream water samples, sampling of soil solution in the riparian zone was made in one of the catchments during 2003-2006. The quantity of DOM differed between the streams, but the seasonal patterns for the two streams were correlated during 2003 and 2004. After wood ash treatment, dissolved organic carbon (DOC) increased significantly in the stream draining the treated catchment. 17 different low molecular mass organic acids (LMMOAs) were measured in the stream water during the whole study period. The most abundant LMMOAs were oxalic- and lactic acid, of which peak concentrations of oxalic acid coincided with those of DOC, while no such relation between the concentrations of DOC and lactic acid could be seen in either of the streams. Some of the most common acids in the soil solution, shikimic acid, citric acid and malic acid were rarely found in the stream water and only then in very low concentrations, thus appearing not to have made the transition from soil to stream water in the same manner as oxalic acid. The wood ash application did not affect the total LMMOA concentration and there was no difference during the investigated period. Of the 17 analysed LMMOAs, only malonic acid appeared affected by wood ash application, with a significant increase during both 2005 and 2006.

  18. Reclamation of potable water from mixed gas streams

    DOEpatents

    Judkins, Roddie R.; Bischoff, Brian L.; Debusk, Melanie Moses; Narula, Chaitanya

    2016-07-19

    An apparatus for separating a liquid from a mixed gas stream can include a wall, a mixed gas stream passageway, and a liquid collection assembly. The wall can include a first surface, a second surface, and a plurality of capillary condensation pores. The capillary condensation pores extend through the wall, and have a first opening on the first surface of the wall, and a second opening on the second surface of the wall. The pore size of the pores can be between about 2 nm to about 100 nm. The mixed gas stream passageway can be in fluid communication with the first opening. The liquid collection assembly can collect liquid from the plurality of pores.

  19. Reclamation of potable water from mixed gas streams

    DOEpatents

    Judkins, Roddie R; Bischoff, Brian L; Debusk, Melanie Moses; Narula, Chaitanya

    2013-08-20

    An apparatus for separating a liquid from a mixed gas stream can include a wall, a mixed gas stream passageway, and a liquid collection assembly. The wall can include a first surface, a second surface, and a plurality of capillary condensation pores. The capillary condensation pores extend through the wall, and have a first opening on the first surface of the wall, and a second opening on the second surface of the wall. The pore size of the pores can be between about 2 nm to about 100 nm. The mixed gas stream passageway can be in fluid communication with the first opening. The liquid collection assembly can collect liquid from the plurality of pores.

  20. Subglacial water flow inferred from stream measurements at South Cascade Glacier, Washington, USA

    USGS Publications Warehouse

    Fountain, A.G.

    1992-01-01

    Comparisons of water discharge and cation load in each of the two main streams indicate that subglacial hydraulic processes differ between drainage basins. One stream drains from a conduit that is isolated in its lower reach from the surrounding subglacial region and receives water routed englacially from the surface. The upper reach of the conduit also receives water rounted englacially from the surface as well as from a distributed subglacial flow system. The other main stream drains from a conduit coupled to a debris layer beneath the glacier. Observations of the layer in natural ice tunnels indicate that the water may flow within a thin layer of debris. A one-dimensional model of flow through the debris layer can explain both the base-flow and diurnal variations of the second main stream. -from Author

  1. Recovery from chronic and snowmelt acidification: Long-term trends in stream and soil water chemistry at the Hubbard Brook Experimental Forest, New Hampshire, USA

    NASA Astrophysics Data System (ADS)

    Fuss, Colin B.; Driscoll, Charles T.; Campbell, John L.

    2015-11-01

    Atmospheric acid deposition of sulfate and nitrate has declined markedly in the northeastern United States due to emissions controls. We investigated long-term trends in soil water (1984-2011) and stream water (1982-2011) chemistry along an elevation gradient of a forested watershed to evaluate the progress of recovery of drainage waters from acidic deposition at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA. We found slowed losses of base cations from soil and decreased mobilization of dissolved inorganic aluminum. Stream water pH at the watershed outlet increased at a rate of 0.01 units yr-1, and the acid neutralizing capacity (ANC) gained 0.88 µeq L-1 yr-1. Dissolved organic carbon generally decreased in stream water and soil solutions, contrary to trends observed at many North American and European sites. We compared whole-year hydrochemical trends with those during snowmelt, which is the highest-flow and lowest ANC period of the year, indicative of episodic acidification. Stream water during snowmelt had long-term trends of increasing ANC and pH at a rate very similar to the whole-year record, with closely related steady decreases in sulfate. A more rapid decline in stream water nitrate during snowmelt compared with the whole-year trend may be due, in part, to the marked decrease in atmospheric nitrate deposition during the last decade. The similarity between the whole-year trends and those of the snowmelt period is an important finding that demonstrates a consistency between recovery from chronic acidification during base flow and abatement of snowmelt acidification.

  2. Nitrogen dynamics at the ground water-surface water interface of a degraded urban stream

    EPA Science Inventory

    Urbanization degrades stream ecosystems by altering hydrology and nutrient dynamics. We investigated temporal and spatial patterns in biogeochemistry and hydrology in and near the stream channel of a geomorphically degraded urban stream of Baltimore County, Maryland, USA. Our o...

  3. Chapter 5: Surface water quality sampling in streams and canals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface water sampling and water quality assessments have greatly evolved in the United States since the 1970s establishment of the Clean Water Act. Traditionally, water quality referred to only the chemical characteristics of the water and its toxicological properties related to drinking water or ...

  4. Machine learning and hurdle models for improving regional predictions of stream water acid neutralizing capacity

    NASA Astrophysics Data System (ADS)

    Povak, Nicholas A.; Hessburg, Paul F.; Reynolds, Keith M.; Sullivan, Timothy J.; McDonnell, Todd C.; Salter, R. Brion

    2013-06-01

    In many industrialized regions of the world, atmospherically deposited sulfur derived from industrial, nonpoint air pollution sources reduces stream water quality and results in acidic conditions that threaten aquatic resources. Accurate maps of predicted stream water acidity are an essential aid to managers who must identify acid-sensitive streams, potentially affected biota, and create resource protection strategies. In this study, we developed correlative models to predict the acid neutralizing capacity (ANC) of streams across the southern Appalachian Mountain region, USA. Models were developed using stream water chemistry data from 933 sampled locations and continuous maps of pertinent environmental and climatic predictors. Environmental predictors were averaged across the upslope contributing area for each sampled stream location and submitted to both statistical and machine-learning regression models. Predictor variables represented key aspects of the contributing geology, soils, climate, topography, and acidic deposition. To reduce model error rates, we employed hurdle modeling to screen out well-buffered sites and predict continuous ANC for the remainder of the stream network. Models predicted acid-sensitive streams in forested watersheds with small contributing areas, siliceous lithologies, cool and moist environments, low clay content soils, and moderate or higher dry sulfur deposition. Our results confirmed findings from other studies and further identified several influential climatic variables and variable interactions. Model predictions indicated that one quarter of the total stream network was sensitive to additional sulfur inputs (i.e., ANC < 100 µeq L-1), while <10% displayed much lower ANC (<50 µeq L-1). These methods may be readily adapted in other regions to assess stream water quality and potential biotic sensitivity to acidic inputs.

  5. Activity of Microorganisms in Acid Mine Water I. Influence of Acid Water on Aerobic Heterotrophs of a Normal Stream

    PubMed Central

    Tuttle, Jon H.; Randles, C. I.; Dugan, P. R.

    1968-01-01

    Comparison of microbial content of acid-contaminated and nonacid-contaminated streams from the same geographical area indicated that nonacid streams contained relatively low numbers of acid-tolerant heterotrophic microorganisms. The acid-tolerant aerobes survived when acid entered the stream and actually increased in number to about 2 × 103 per ml until the pH approached 3.0. The organisms then represented the heterotrophic aerobic microflora of the streams comprised of a mixture of mine drainage and nonacid water. A stream which was entirely acid drainage did not have a similar microflora. Most gram-positive aerobic and anaerobic bacteria died out very rapidly in acidic water, and they comprised a very small percentage of the microbial population of the streams examined. Iron- and sulfur-oxidizing autotrophic bacteria were present wherever mine water entered a stream system. The sulfur-oxidizing bacteria predominated over iron oxidizers. Ecological data from the field were verified by laboratory experiments designed to simulate stream conditions. PMID:5650063

  6. Survival of Escherichia coli and Enterococcus in Stream Water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    E. coli and Enterococcus indicate fecal contamination and are used for monitoring of lakes, streams, and rivers. Transport of bacteria from manured or pastured lands can result in large bacterial loads from both small and large runoff events and the persistence of bacteria following these loadings i...

  7. POTENTIAL IMPACTS OF ORGANIC WASTES ON SMALL STREAM WATER QUALITY

    EPA Science Inventory

    We monitored concentrations of dissolved organic carbon (DOC), dissolved oxygen (DO) and other parameters in 17 small streams of the South Fork Broad River (SFBR) watershed on a monthly basis for 15 months. Our monthly monitoring results showed a strong inverse relationship betwe...

  8. Supercharged Snails for Stream Ecology & Water-Quality Studies

    ERIC Educational Resources Information Center

    Stewart, Arthur J.; Ryon, Michael G.

    2003-01-01

    Gill-breathing freshwater snails (Family "Pleuroceridae") are ecologically important, abundant in many streams in the United States, and easy to collect and maintain under classroom conditions. These snails can be used in classroom tests to demonstrate effects of pollutants on aquatic organisms. In more advanced classes, students can cage the…

  9. Data on stream-water and bed-sediment quality in the vicinity of Leviathan Mine, Alpine County, California, and Douglas County, Nevada, September 1998

    USGS Publications Warehouse

    Thomas, Karen A.; Lico, Michael S.

    2000-01-01

    The U.S. Geological Survey (USGS) con- ducted a chemical assessment of streams in the Leviathan Mine and adjacent areas in September 1998. On-site measurements of streamflow, pH, dissolved oxygen, temperature, specific conductance, and at most sites alkalinity, bicarbonate, and carbonate were made at 14 sites. Water samples were collected for chemical analyses of nutrients, major ions, trace elements, and organic carbon. Bed-sediment samples of fine-grained sediment in representative depositional areas at each sampling location were collected for chemical analyses of major and trace elements, total carbon, inorganic carbon, and organic carbon.

  10. Model-estimated ground-water recharge and hydrograph of ground-water discharge to a stream

    USGS Publications Warehouse

    Rutledge, A.T.

    1997-01-01

    The computer model PULSE, described in this report, can be used to construct a hydrograph of ground-water discharge to a stream. The model is applicable to a ground-water flow system that is driven by areally uniform recharge to the water table, and in which ground water discharges to a gaining stream. One of the two formulations used by the model allows for an instantaneous recharge pulse and subsequent ground-water discharge to the stream. The other formulation, which allows for a gradual hydrologic gain or loss term in addition to the instantaneous pulse, can be used to simulate the effects of gradual recharge to the water table, ground-water evapotranspiration, or downward leakage to a deeper aquifer.

  11. Geochemical mass-balance relationships for selected ions in precipitation and stream water, Catoctin Mountains, Maryland.

    USGS Publications Warehouse

    Katz, B.G.; Bricker, O.P.; Kennedy, M.M.

    1985-01-01

    Results of a study of input/output mass balances for major ions based on the chemical composition of precipitation and stream-water, geochemical reactions with different loading rates of hydrogen ion, and watershed processes influencing the chemical character of stream-waters in two small watershed areas are reported with a view to predicting the effect of additions of acidic rain to the watershed systems. Geochemical weathering processes account for the observed changes in the chemistry of stream flow. Although present in bedrock in extremely small quantities, calcite plays an important role in neutralization of the total hydrogen-ion input.-M.S.

  12. Water Mites (Acari: Hydrachnida) of Ozark Streams - Abundance, Species Richness, and Potential as Environmental Indicators

    NASA Astrophysics Data System (ADS)

    Radwell, A. J.; Brown, A. V.

    2005-05-01

    Because water mites are tightly linked to other stream metazoans through parasitism and predation, they are potentially effective indicators of environmental quality. Meiofauna (80 μm to 1 mm) were sampled from headwater riffles of 11 Ozark streams to determine relative abundance and densities of major meiofauna taxa. Water mites comprised 15.3% of the organisms collected exceeded only by chironomids (50.2%) and oligochaetes (17.8%), and mean water mite density among the 11 streams was 265 organisms per liter. The two streams that differed the most in environmental quality were sampled using techniques suitable for identification of species. An estimated 32 species from 20 genera and 13 families were found in the least disturbed stream; an estimated 19 species from 13 genera and 8 families were found in the most disturbed stream. This preliminary finding supports the notion that water mite species richness declines in response to environmental disturbance. Many species could only be identified as morphospecies of particular genera, but the ongoing taxonomic revision of Hydrachnida is expected to provide needed information. A collaborative effort between those interested in taxonomy/systematics of water mites and ecologists interested in the significance of water mites in aquatic communities could prove mutually beneficial.

  13. Remote Monitoring, Inorganic Monitoring

    EPA Science Inventory

    This chapter provides an overview of applicability, amenability, and operating parameter ranges for various inorganic parameters:this chapter will also provide a compilation of existing and new online technologies for determining inorganic compounds in water samples. A wide vari...

  14. Effects of an off-stream watering facility on cattle behavior and instream E. coli levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive levels of fecal indicator bacteria are the leading cause of water quality impairment in Texas, and livestock with direct access to water bodies are potentially a significant source of these bacteria. To help address this source, the effect of providing alternative off-stream watering facil...

  15. Cold-water refuges for climate resilience in Oregon coastal stream

    EPA Science Inventory

    Many rivers and streams in the Pacific Northwest are currently listed as impaired under the Clean Water Act as a result of high summer water temperatures. Adverse effects of warm waters include impacts to salmon and steelhead populations that may already be stressed by habitat al...

  16. Ecohydrologic separation of water between trees and streams in a Mediterranean climate

    EPA Science Inventory

    Water movement in upland humid watersheds from the soil surface to the stream is often described using the concept of translatory flow, which assumes that water entering the soil as precipitation displaces the water that was present previously, pushing it deeper into the soil and...

  17. Using electronic conductivity and hardness data for rapid assessment of stream water quality.

    PubMed

    Thompson, Michael Y; Brandes, David; Kney, Arthur D

    2012-08-15

    A graphical screening method was previously developed by Kney and Brandes (2007) for assessing stream water quality data using electronic conductivity (EC) and alkalinity data. The method was aimed at providing citizen scientists involved in stream monitoring programs with a relatively simple way to interpret EC data. The method utilizes a plot of EC against concurrent alkalinity data, and is used to distinguish EC values for impacted or degraded streams from those that can be considered background values in a particular geologic setting. The method performs well in areas underlain by carbonate bedrock, as streams in those areas characteristically have EC values that are strongly correlated with alkalinity. However, in areas of low stream alkalinity (less than approximately 50 mg/L as CaCO(3)), the Kney and Brandes (2007) method was found to be much less effective in identifying impacted streams. This paper extends the graphical screening approach to streams with low alkalinity, specifically regions underlain by clastic sedimentary or crystalline bedrock, by using the strong correlation between EC and total hardness (TH). A baseline relationship of EC vs. TH is developed using surface water chemistry data from Hydrologic Benchmark Network streams (deemed as having minimal anthropogenic impacts) and regional groundwater quality data. The usefulness of the method is demonstrated by application to publicly available stream chemistry data and to field data collected from streams of eastern Pennsylvania under baseflow conditions. Results demonstrate that for streams with alkalinity <75 mg/L as CaCO(3), the TH-based graphical screening method should be used rather than the alkalinity-based method of Kney and Brandes (2007). PMID:22495016

  18. Evaluation of USEPA method 1622 for detection of Cryptosporidium oocysts in stream waters

    USGS Publications Warehouse

    Simmons, O. D., III; Sobsey, M.D.; Schaefer, F. W., III; Francy, D.S.; Nally, R.A.; Heaney, C.D.

    2001-01-01

    To improve surveillance for Cryptosporidium oocysts in water, the US Environmental Protection Agency developed method 1622, which consists of filtration, concentration, immunomagnetic separation, fluorescent antibody and 4, 6-diamidino-2-phenylindole (DAPI) counter-staining, and microscopic evaluation. Two filters were compared for analysis of 11 stream water samples collected throughout the United States. Replicate 10-L stream water samples (unspiked and spiked with 100-250 oocysts) were tested to evaluate matrix effects. Oocyst recoveries from the stream water samples averaged 22% (standard deviation [SD] = ??17%) with a membrane disk and 12% (SD = ??6%) with a capsule filter. Oocyst recoveries from reagent water precision and recovery samples averaged 39% (SD = ??13%) with a membrane disk and 47% (SD = ??19%) with a capsule filter. These results demonstrate that Cryptosporidium oocysts can be recovered from stream waters using method 1622, but recoveries are lower than those from reagent-grade water. This research also evaluated concentrations of indicator bacteria in the stream water samples. Because few samples were oocyst-positive, relationships between detections of oocysts and concentrations of indicator organisms could not be determined.

  19. Assessing the Effects of Water Right Purchases on Stream Temperatures and Fish Habitat

    NASA Astrophysics Data System (ADS)

    Elmore, L.; Null, S. E.

    2012-12-01

    Warm stream temperature and low flow conditions are limiting factors for native trout species in Nevada's Walker River. Water rights purchases are being considered to increase instream flow and improve habitat conditions. However, the effect of water rights purchases on stream temperatures and fish habitat have yet to be assessed. Manipulating flow conditions affect stream temperatures by altering water depth, velocity, and thermal mass. This study uses the River Modeling System (RMSv4), an hourly, physically-based hydrodynamic and water quality model, to estimate flows and stream temperatures in the Walker River. The model is developed for two wet years (2010-2011). Study results highlight reaches with cold-water habitat that is suitable for native trout species. Previous research on the Walker River has evaluated instream flow changes with water rights purchases. This study incorporates stream temperatures as a proxy for trout habitat, and thus explicitly incorporates water quality and fish habitat into decision-making regarding water rights purchases. Walker River

  20. Problems associated with estimating ground water discharge and recharge from stream-discharge records

    USGS Publications Warehouse

    Halford, K.J.; Mayer, G.C.

    2000-01-01

    Ground water discharge and recharge frequently have been estimated with hydrograph-separation techniques, but the critical assumptions of the techniques have not been investigated. The critical assumptions are that the hydraulic characteristics of the contributing aquifer (recession index) can be estimated from stream-discharge records; that periods of exclusively ground water discharge can be reliably identified; and that stream-discharge peaks approximate the magnitude and tinting of recharge events. The first assumption was tested by estimating the recession index from st earn-discharge hydrographs, ground water hydrographs, and hydraulic diffusivity estimates from aquifer tests in basins throughout the eastern United States and Montana. The recession index frequently could not be estimated reliably from stream-discharge records alone because many of the estimates of the recession index were greater than 1000 days. The ratio of stream discharge during baseflow periods was two to 36 times greater than the maximum expected range of ground water discharge at 12 of the 13 field sites. The identification of the ground water component of stream-discharge records was ambiguous because drainage from bank-storage, wetlands, surface water bodies, soils, and snowpacks frequently exceeded ground water discharge and also decreased exponentially during recession periods. The timing and magnitude of recharge events could not be ascertained from stream-discharge records at any of the sites investigated because recharge events were not directly correlated with stream peaks. When used alone, the recession-curve-displacement method and other hydrograph-separation techniques are poor tools for estimating ground water discharge or recharge because the major assumptions of the methods are commonly and grossly violated. Multiple, alternative methods of estimating ground water discharge and recharge should be used because of the uncertainty associated with any one technique.

  1. Water discharged from the gulf stream north of Cape Hatteras. (Reannouncement with new availability information)

    SciTech Connect

    Churchill, J.H.; Cornillon, P.C.

    1991-12-31

    Satellite radiometer-derived sea surface temperature images together with moored instrument and hydrographic survey data indicate that water ejected from the Gulf Stream often occupies the upper 200 m of the water column over the continental slope between Cape Hatteras and Hudson Canyon. At times this water resembles the energetic Gulf Stream frontal eddies commonly seen to the south of Cape Hatteras. However, many of the observed parcels of this water differ markedly from frontal eddies and Gulf Stream warm-core rings and so appear to form a class of discharged Gulf Stream water distinct from any previously reported. These parcels generally cover a broad area (compared with frontal eddies), contain relatively weak currents (generally < 40 cm/s at 100 m), and are remarkably long-lived (sometimes distinguishable for more than 2 months). Sanity anomaly distributions indicate that despite their persistence, these water masses contain intrusions of and mix with surrounding lower-salinity water, particularly in the upper So m. Continuity of various tracers along surfaces reveals that the discharged Gulf Stream water observed near the sea surface originated within the nutrient-bearing stratum of the Gulf Stream, having upwelled hundreds of meters along density surfaces. As a result, it tends to enhance nutrient concentrations over the continental slope, to a significant extent at 100 m depth but only marginally at 50 m depth. By contrast, this water does not carry unusually large kinetic energy densities into the slope region, but apparently gives up a good deal of kinetic energy, on the order of 10,000 sq cm/sec sq. per unit mass, while leaving the Gulf Stream.

  2. Bacterial production in the water column of small streams highly depends on terrestrial dissolved organic carbon

    NASA Astrophysics Data System (ADS)

    Graeber, Daniel; Poulsen, Jane R.; Rasmussen, Jes J.; Kronvang, Brian; Zak, Dominik; Kamjunke, Norbert

    2016-04-01

    In the recent years it has become clear that the largest part of the terrestrial dissolved organic carbon (DOC) pool is removed on the way from the land to the ocean. Yet it is still unclear, where in the freshwater systems terrestrial DOC is actually taken up, and for streams DOC uptake was assumed to happen mostly at the stream bottom (benthic zone). However, a recent monitoring study implies that water column but not benthic bacteria are strongly affected by the amount and composition of DOM entering streams from the terrestrial zone. We conducted an experiment to compare the reaction of the bacterial production and heterotrophic uptake in the water column and the benthic zone to a standardized source of terrestrial DOC (leaf leachate from Beech litter). In detail, we sampled gravel and water from eight streams with a gradient in stream size and land use. For each stream four different treatments were incubated at 16°C for three days and each stream: filtered stream water with gravel stones (representing benthic zone bacteria) or unfiltered stream water (representing water column bacteria), both either with (n = 5) or, without (n = 3) leaf leachate. We found that the bacterial uptake of leaf litter DOC was higher for the benthic zone likely due to the higher bacterial production compared to the water column. In contrast, the bacterial production per amount of leaf leachate DOC taken up was significantly higher for the bacteria in the water column than for those in the benthic zone. This clearly indicates a higher growth efficiency with the leaf leachate DOC for the bacteria in the water column than in the benthic zone. We found a high variability for the growth efficiency in the water column, which was best explained by a negative correlation of the DOC demand with stream width (R² = 0.86, linear correlation of log-transformed data). This was not the case for the benthic zone bacteria (R² = 0.02). This implies that water column bacteria in very small streams

  3. Stormwater Management Impacts on Urban Stream Water Quality and Quantity During and After Development in Clarksburg, MD

    EPA Science Inventory

    Urbanization and urban land use leads to degradation of local stream habitat generally termed as ‘urban stream syndrome.’ Best Management Practices (BMPs) are often used in an attempt to mitigate water quality and water quantity degradation in urban streams. Traditional developme...

  4. Effects of Urbanization on Stream Water Quality in the City of Atlanta, Georgia, USA

    NASA Astrophysics Data System (ADS)

    Peters, N. E.

    2009-05-01

    A long-term stream water-quality monitoring network was established in the City of Atlanta (COA) during 2003 to assess baseline water-quality conditions and the effects of urbanization on stream water quality. Routine hydrologically-based manual stream sampling, including several concurrent manual point and equal width increment sampling, was conducted approximately 12 times per year at 21 stations, with drainage areas ranging from 3.7 to 232 km2. Eleven of the stations are real-time (RT) water-quality stations having continuous measures of stream stage/discharge, pH, dissolved oxygen, specific conductance, water temperature, and turbidity, and automatic samplers for stormwater collection. Samples were analyzed for field parameters, and a broad suite of water-quality and sediment-related constituents. This paper summarizes an evaluation of field parameters and concentrations of major ions, minor and trace metals, nutrient species (nitrogen and phosphorus), and coliform bacteria among stations and with respect to watershed characteristics and plausible sources from 2003 through September 2007. The concentrations of most constituents in the COA streams are statistically higher than those of two nearby reference streams. Concentrations are statistically different among stations for several constituents, despite high variability both within and among stations. The combination of routine manual sampling, automatic sampling during stormflows, and real-time water-quality monitoring provided sufficient information about the variability of urban stream water quality to develop hypotheses for causes of water-quality differences among COA streams. Fecal coliform bacteria concentrations of most individual samples at each station exceeded Georgia's water-quality standard for any water-usage class. High chloride concentrations occur at three stations and are hypothesized to be associated with discharges of chlorinated combined sewer overflows, drainage of swimming pool(s), and

  5. Regional Geochemical Results from Analyses of Stream-Water, Stream-Sediment, Soil, Soil-Water, Bedrock, and Vegetation Samples, Tangle Lakes District, Alaska

    USGS Publications Warehouse

    Wang, Bronwen; Gough, L.P.; Wanty, R.B.; Lee, G.K.; Vohden, James; O'Neill, J. M.; Kerin, L.J.

    2008-01-01

    We report chemical analyses of stream-water, stream-sediment, soil, soil-water, bedrock, and vegetation samples collected from the headwaters of the Delta River (Tangle Lakes District, Mount Hayes 1:250,000-scale quadrangle) in east-central Alaska for the period June 20-25, 2006. Additionally, we present mineralogic analyses of stream sediment, concentrated by panning. The study area includes the southwestward extent of the Bureau of Land Management (BLM) Delta River Mining District (Bittenbender and others, 2007), including parts of the Delta River Archeological District, and encompasses an area of about 500 km2(approximately bordered by the Denali Highway to the south, near Round Tangle Lake, northward to the foothills of the Alaska Range (fig. 1). The primary focus of this study was the chemical characterization of native materials, especially surface-water and sediment samples, of first-order streams from the headwaters of the Delta River. The impetus for this work was the need, expressed by the Alaska Department of Natural Resources (ADNR), for an inventory of geochemical and hydrogeochemical baseline information about the Delta River Mining District. This information is needed because of a major upturn in exploration, drilling, and general mineral-resources assessments in the region since the late 1990s. Currently, the study area, called the 'MAN Project' area is being explored by Pure Nickel, Inc. (http://www.purenickel.com/s/MAN_Alaska.asp), and includes both Cu-Au-Ag and Ni-Cu-PGE (Pt-Pd-Au-Ag) mining claims. Geochemical data on surface-water, stream-sediment, soil, soil-water, grayleaf willow (Salix glauca L.), and limited bedrock samples are provided along with the analytical methodologies used and panned-concentrate mineralogy. We are releasing the data at this time with only minimal interpretation.

  6. Changing of water status along a small stream due to urbanization

    NASA Astrophysics Data System (ADS)

    Gribovszki, Z.; Kalicz, P.; Csáfordi, P.; Szita, R.; Sermaul, K.

    2012-04-01

    Considerable qualitative and quantitative changes can be generally detected in case of urban sections of the streams as the results of strong human interventions along the stream channel or in the drainage basin in urban areas. The water status becomes worse and the water regime becomes more extreme. The negative changes have an effect on the broader environment and they bring usually diminution of the biodiversity. The assessments of the above mentioned combined effects are very important from the viewpoint of the good state of the water systems, which is the main purpose in the European Water Framework Directive. Water status changing are monitored and analysed along different (natural, rural and urbanized) sections of a small stream (Rák Brook in Sopron) taking into account the connection of the hydrological and the water quality monitoring expediently. Seven monitoring points are set up along the stream system of the Rák Brook from the headwaters to the stream mouth, in designation of the points mainly focusing the change of the surface cover and human impacts. Samples were taken on the measurement points fortnightly or for flood-linked between the dates 01.09.2010-01.03.2012. The following features were examined: hydro-morphological (velocity, discharge, stream bed sediment type), physico-chemical (pH, conductivity, suspended sediment), chemical (sulphate, chloride, COD, ammonium, nitrate, total phosphorous), and biological (makrozoobenthos) parameters. Simple and multivariate statistical methods were used for data processing to present the magnitude of the differences between the stream sections. Based on the results the effect of the different degree of urbanization on the drainage basin and the hydro-morphological interventions in the stream bed was well demonstrable.

  7. Estimation and characterization of physical and inorganic chemical indicators of water quality by using SAR images

    NASA Astrophysics Data System (ADS)

    Shareef, Muntadher A.; Toumi, Abdelmalek; Khenchaf, Ali

    2015-10-01

    Recently, remote sensing is considering one of the most important tools in studies of water scattering and water characterization. Traditional methods for monitoring pollutants depended on optical satellite rather than Radar data. Thus, many of Water Quality Parameters (WQP) from optical imagery are still limited. In this paper, a new approach based on the TerraSAR-X images has been presented which it is used to map the region of interest and to estimate physical and chemical WQPs. This approach based on a Small Perturbation Model (SPM) for the electromagnetic scattering is applied by using the Elfouhaily spectrum. A series of inversions have been included in this model started by finding the reflectivity from backscattering coefficients which are calculated from SAR images. Another inversion has been applied to find dielectric constant from the calculation models of the reflectivity (in HH and VV polarizations). Then, a Stogryn Debye formulation has been used to estimate temperature and salinity of water surface from SAR images. After many derivations we got a new model able to estimate temperature and salinity directly from backscattering coefficients obtained from radar images. Inorganic chemical parameters which are represented by Total Dissolved Salts (TDS) and the Electrical Conductivity (EC) are estimated directly from salinity. A tow dataset of instu data have been used to validate this work. The validation included a comparison between parameters measured in situ and those estimated from Terra SAR-X image.

  8. Fumigant methyl iodide can methylate inorganic mercury species in natural waters.

    PubMed

    Yin, Yongguang; Li, Yanbin; Tai, Chao; Cai, Yong; Jiang, Guibin

    2014-01-01

    Methyl iodide or iodomethane (CH3I) has recently been registered as a fumigant in many countries, although its environmental impacts are not well understood. Here we report the results of a study on the methylation of mercury by CH3I in natural water by incubation experiments using both Hg ((199)HgCl2 and CH3(201)Hg(+))- and hydrogen (CD3I)-stable isotope addition techniques. We find that methylation of Hg(0), Hg2(2+) and Hg(2+) by CH3I can occur in natural water under sunlight, while only Hg(0) and Hg2(2+) can be methylated in deionized water. We propose that the methylation of Hg by CH3I in natural waters is mediated by sunlight and involves two steps, the reduction of Hg(2+) to Hg(0)/Hg2(2+) and the subsequent methylation of Hg(0)/Hg2(2+) by CH3I. Further quantitative assessment suggests that CH3I-involved methylation of inorganic Hg could be an important source of CH3Hg(+) in an environment where CH3I has been used in large amounts as a fumigant. PMID:25137238

  9. Using the soil and water assessment tool to estimate dissolved inorganic nitrogen water pollution abatement cost functions in central portugal.

    PubMed

    Roebeling, P C; Rocha, J; Nunes, J P; Fidélis, T; Alves, H; Fonseca, S

    2014-01-01

    Coastal aquatic ecosystems are increasingly affected by diffuse source nutrient water pollution from agricultural activities in coastal catchments, even though these ecosystems are important from a social, environmental and economic perspective. To warrant sustainable economic development of coastal regions, we need to balance marginal costs from coastal catchment water pollution abatement and associated marginal benefits from coastal resource appreciation. Diffuse-source water pollution abatement costs across agricultural sectors are not easily determined given the spatial heterogeneity in biophysical and agro-ecological conditions as well as the available range of best agricultural practices (BAPs) for water quality improvement. We demonstrate how the Soil and Water Assessment Tool (SWAT) can be used to estimate diffuse-source water pollution abatement cost functions across agricultural land use categories based on a stepwise adoption of identified BAPs for water quality improvement and corresponding SWAT-based estimates for agricultural production, agricultural incomes, and water pollution deliveries. Results for the case of dissolved inorganic nitrogen (DIN) surface water pollution by the key agricultural land use categories ("annual crops," "vineyards," and "mixed annual crops & vineyards") in the Vouga catchment in central Portugal show that no win-win agricultural practices are available within the assessed BAPs for DIN water quality improvement. Estimated abatement costs increase quadratically in the rate of water pollution abatement, with largest abatement costs for the "mixed annual crops & vineyards" land use category (between 41,900 and 51,900 € tDIN yr) and fairly similar abatement costs across the "vineyards" and "annual crops" land use categories (between 7300 and 15,200 € tDIN yr). PMID:25602550

  10. Organic and inorganic composition and microbiology of produced waters from Pennsylvania shale gas wells

    USGS Publications Warehouse

    Akob, Denise M.; Cozzarelli, Isabelle M.; Dunlap, Darren S.; Rowan, Elisabeth L.; Lorah, Michelle M.

    2015-01-01

    Hydraulically fractured shales are becoming an increasingly important source of natural gas production in the United States. This process has been known to create up to 420 gallons of produced water (PW) per day, but the volume varies depending on the formation, and the characteristics of individual hydraulic fracture. PW from hydraulic fracturing of shales are comprised of injected fracturing fluids and natural formation waters in proportions that change over time. Across the state of Pennsylvania, shale gas production is booming; therefore, it is important to assess the variability in PW chemistry and microbiology across this geographical span. We quantified the inorganic and organic chemical composition and microbial communities in PW samples from 13 shale gas wells in north central Pennsylvania. Microbial abundance was generally low (66–9400 cells/mL). Non-volatile dissolved organic carbon (NVDOC) was high (7–31 mg/L) relative to typical shallow groundwater, and the presence of organic acid anions (e.g., acetate, formate, and pyruvate) indicated microbial activity. Volatile organic compounds (VOCs) were detected in four samples (∼1 to 11.7 μg/L): benzene and toluene in the Burket sample, toluene in two Marcellus samples, and tetrachloroethylene (PCE) in one Marcellus sample. VOCs can be either naturally occurring or from industrial activity, making the source of VOCs unclear. Despite the addition of biocides during hydraulic fracturing, H2S-producing, fermenting, and methanogenic bacteria were cultured from PW samples. The presence of culturable bacteria was not associated with salinity or location; although organic compound concentrations and time in production were correlated with microbial activity. Interestingly, we found that unlike the inorganic chemistry, PW organic chemistry and microbial viability were highly variable across the 13 wells sampled, which can have important implications for the reuse and handling of these fluids

  11. Paraoxonase 1 activity in subchronic low-level inorganic arsenic exposure through drinking water.

    PubMed

    Afolabi, Olusegun K; Wusu, Adedoja D; Ogunrinola, Olufunmilayo O; Abam, Esther O; Babayemi, David O; Dosumu, Oluwatosin A; Onunkwor, Okechukwu B; Balogun, Elizabeth A; Odukoya, Olusegun O; Ademuyiwa, Oladipo

    2016-02-01

    Epidemiological evidences indicate close association between inorganic arsenic exposure via drinking water and cardiovascular diseases. While the exact mechanism of this arsenic-mediated increase in cardiovascular risk factors remains enigmatic, epidemiological studies indicate a role for paraoxonase 1 (PON1) in cardiovascular diseases. To investigate the association between inorganic arsenic exposure and cardiovascular diseases, rats were exposed to sodium arsenite (trivalent; 50, 100, and 150 ppm As) and sodium arsenate (pentavalent; 100, 150, and 200 ppm As) in their drinking water for 12 weeks. PON1 activity towards paraoxon (PONase) and phenylacetate (AREase) in plasma, lipoproteins, hepatic, and brain microsomal fractions were determined. Inhibition of PONase and AREase in plasma and HDL characterized the effects of the two arsenicals. While the trivalent arsenite inhibited PONase by 33% (plasma) and 46% (HDL), respectively, the pentavalent arsenate inhibited the enzyme by 41 and 34%, respectively. AREase activity was inhibited by 52 and 48% by arsenite, whereas the inhibition amounted to 72 and 67%, respectively by arsenate. The pattern of inhibition in plasma and HDL indicates that arsenite induced a dose-dependent inhibition of PONase whereas arsenate induced a dose-dependent inhibition of AREase. In the VLDL + LDL, arsenate inhibited PONase and AREase while arsenite inhibited PONase. In the hepatic and brain microsomal fractions, only the PONase enzyme was inhibited by the two arsenicals. The inhibition was more pronounced in the hepatic microsomes where a 70% inhibition was observed at the highest dose of pentavalent arsenic. Microsomal cholesterol was increased by the two arsenicals resulting in increased cholesterol/phospholipid ratios. Our findings indicate that decreased PON1 activity observed in arsenic exposure may be an incipient biochemical event in the cardiovascular effects of arsenic. Modulation of PON1 activity by arsenic may also be

  12. Water chemistry-based classification of streams and implications for restoring mined Appalachian watersheds

    SciTech Connect

    Merovich, G.T.; Stiles, J.M.; Petty, J.T.; Ziemkiewicz, P.F.; Fulton, J.B.

    2007-07-15

    We analyzed seasonal water samples from the Cheat and Tygart Valley river basins, West Virginia, USA, in an attempt to classify streams based on water chemistry in this coal-mining region. We also examined temporal variability among water samples. Principal component analysis identified two important dimensions of variation in water chemistry. This variation was determined largely by mining-related factors (elevated metals, sulfates, and conductivity) and an alkalinity-hardness gradient. Cluster analysis grouped water samples into six types that we described as reference, soft, hard, transitional, moderate acid mine drainage, and severe acid mine drainage. These types were statistically distinguishable in multidimensional space. Classification tree analysis confirmed that chemical constituents related to acid mine drainage and acid rain distinguished these six groups. Hard, soft, and severe acid mine drainage type streams were temporally constant compared to streams identified as reference, transitional, and moderate acid mine drainage type, which had a greater tendency to shift to a different water type between seasons. Our research is the first to establish a statistically supported stream classification system in mined watersheds. The results suggest that human-related stressors superimposed on geology are responsible for producing distinct water quality types in this region as opposed to more continuous variation in chemistry that would be expected in an unimpacted setting. These findings provide a basis for simplifying stream monitoring efforts, developing generalized remediation strategies, and identifying specific remediation priorities in mined Appalachian watersheds.

  13. Chemical budgets and stream-chemistry dynamics of a headwater stream in the Catskill Mountains of New York, October 1, 1983 through September 30, 1985. Water Resources Investigation

    SciTech Connect

    Murdoch, P.S.

    1991-01-01

    The purpose of the study was to evaluate the chemical effects of atmospherically derived acidity on stream water in Biscuit Brook and to compare the effects of stormflows on the annual chemical budgets with the effects of base flow. This report summarizes the results of water-quality analyses and chemical budgets on Biscuit Brook during water years 1984 and 1985, and assesses the relation between discharge and stream chemistry during 14 storms observed from April 1983 through May 1986 at Biscuit Brook.

  14. Factors affecting reservoir and stream-water quality in the Cambridge, Massachusetts, drinking-water source area and implications for source-water protection

    USGS Publications Warehouse

    Waldron, Marcus C.; Bent, Gardner C.

    2001-01-01

    milligrams per liter), and lowest in Fresh Pond (54 milligrams per liter). Bed sediments in Hobbs Brook and Stony Brook Reservoirs were enriched in iron, manganese, and arsenic relative to those in the impounded lower Charles River in Boston, Massachusetts. Trophic state indices, calculated for each reservoir based on nutrient concentrations, water-column transparency, and phytoplankton abundances, indicated that the upper and middle basins of Hobbs Brook Reservoir were moderately to highly productive and likely to produce algal blooms; the lower basin of Hobbs Brook Reservoir and Stony Brook Reservoir were similar and intermediate in productivity, and Fresh Pond was relatively unproductive and unlikely to produce algal blooms. This pattern is likely due to sedimentation of organic and inorganic particles in the three basins of Hobbs Brook Reservoir and in Stony Brook Reservoir. Molar ratios of nitrogen to phosphorus ranged from 55 in Stony Brook Reservoir to 120 in Hobbs Brook Reservoir, indicating that phytoplankton algae in these water bodies may be phosphorus limited and therefore sensitive to small increases in phosphorus loading from the drainage basin. Nitrogen loads were found to be less important than phosphorus to the trophic condition of the reservoirs. Hobbs Brook and Stony Brook, the two principle streams draining the Cambridge drinking-water source area, differed in their relative contributions to many of the estimated constituent loads. The estimated load of fecal coliform bacteria was more than seven times larger for the mainly residential Stony Brook subbasin upstream from Kendal Green, Mass., than it was for the more commercial and industrial Hobbs Brook subbasin, though the drainage areas of the two subbasins differ only by about 20 percent. The State standard for fecal coliform bacteria in streams in the Cambridge drinking-water source area (20 colony forming units per 100 milliliters) was exceeded at all sampling stations. Estimated s

  15. Assessing effects of water abstraction on fish assemblages in Mediterranean streams

    USGS Publications Warehouse

    Benejam, Lluis; Angermeier, Paul L.; Munne, Antoni; García-Berthou, Emili

    2010-01-01

    1. Water abstraction strongly affects streams in arid and semiarid ecosystems, particularly where there is a Mediterranean climate. Excessive abstraction reduces the availability of water for human uses downstream and impairs the capacity of streams to support native biota. 2. We investigated the flow regime and related variables in six river basins of the Iberian Peninsula and show that they have been strongly altered, with declining flows (autoregressive models) and groundwater levels during the 20th century. These streams had lower flows and more frequent droughts than predicted by the official hydrological model used in this region. Three of these rivers were sometimes dry, whereas there were predicted by the model to be permanently flowing. Meanwhile, there has been no decrease in annual precipitation. 3. We also investigated the fish assemblage of a stream in one of these river basins (Tordera) for 6 years and show that sites more affected by water abstraction display significant differences in four fish metrics (catch per unit effort, number of benthic species, number of intolerant species and proportional abundance of intolerant individuals) commonly used to assess the biotic condition of streams. 4. We discuss the utility of these metrics in assessing impacts of water abstraction and point out the need for detailed characterisation of the natural flow regime (and hence drought events) prior to the application of biotic indices in streams severely affected by water abstraction. In particular, in cases of artificially dry streams, it is more appropriate for regulatory agencies to assign index scores that reflect biotic degradation than to assign ‘missing’ scores, as is presently customary in assessments of Iberian streams.

  16. Classifying the health of Connecticut streams using benthic macroinvertebrates with implications for water management.

    PubMed

    Bellucci, Christopher J; Becker, Mary E; Beauchene, Mike; Dunbar, Lee

    2013-06-01

    Bioassessments have formed the foundation of many water quality monitoring programs throughout the United States. Like many state water quality programs, Connecticut has developed a relational database containing information about species richness, species composition, relative abundance, and feeding relationships among macroinvertebrates present in stream and river systems. Geographic Information Systems can provide estimates of landscape condition and watershed characteristics and when combined with measurements of stream biology, provide a useful visual display of information that is useful in a management context. The objective of our study was to estimate the stream health for all wadeable stream kilometers in Connecticut using a combination of macroinvertebrate metrics and landscape variables. We developed and evaluated models using an information theoretic approach to predict stream health as measured by macroinvertebrate multimetric index (MMI) and identified the best fitting model as a three variable model, including percent impervious land cover, a wetlands metric, and catchment slope that best fit the MMI scores (adj-R (2) = 0.56, SE = 11.73). We then provide examples of how modeling can augment existing programs to support water management policies under the Federal Clean Water Act such as stream assessments and anti-degradation. PMID:23609302

  17. Classifying the Health of Connecticut Streams Using Benthic Macroinvertebrates with Implications for Water Management

    NASA Astrophysics Data System (ADS)

    Bellucci, Christopher J.; Becker, Mary E.; Beauchene, Mike; Dunbar, Lee

    2013-06-01

    Bioassessments have formed the foundation of many water quality monitoring programs throughout the United States. Like many state water quality programs, Connecticut has developed a relational database containing information about species richness, species composition, relative abundance, and feeding relationships among macroinvertebrates present in stream and river systems. Geographic Information Systems can provide estimates of landscape condition and watershed characteristics and when combined with measurements of stream biology, provide a useful visual display of information that is useful in a management context. The objective of our study was to estimate the stream health for all wadeable stream kilometers in Connecticut using a combination of macroinvertebrate metrics and landscape variables. We developed and evaluated models using an information theoretic approach to predict stream health as measured by macroinvertebrate multimetric index (MMI) and identified the best fitting model as a three variable model, including percent impervious land cover, a wetlands metric, and catchment slope that best fit the MMI scores (adj- R 2 = 0.56, SE = 11.73). We then provide examples of how modeling can augment existing programs to support water management policies under the Federal Clean Water Act such as stream assessments and anti-degradation.

  18. Water Quality Interpolation Using Various In-Stream Distance Weighting Metrics

    NASA Astrophysics Data System (ADS)

    Saia, S. M.; Walter, T.; Sullivan, P.; Christie, R.

    2012-12-01

    Interpolation of water quality samples along the reach of a stream can be used to (1) extend point data to un-sampled locations along the stream network, (2) identify spatial patterns in water quality, and (3) understand how natural and human factors shape these patterns. Kriging, one of the most commonly used geospatial interpolation methods, assumes that nearby sites are spatially auto-correlated; sites closer together have more in common than sites further away. Studies have introduced kriging methods that weight in-stream distance metrics with either landscape attributes (i.e. topography, land use, temperature, and various soil properties) or stream order. Here we present a weighting scheme that combines both surrounding landscape attributes with stream order. We use R, an open-source programming language, to interpolate water quality data collected from the Mianus River in Westchester County, New York. As the major drinking water supply for approximately 100,000 people in Connecticut and New York, the Mianus River watershed community values the cleanliness of its water for recreational activities as well as the sustenance of terrestrial and aquatic wildlife. With the in-stream interpolation results, we can gain a better understanding of factors contributing to water quality issues and observed biogeochemical patterns within the watershed. For example, we can help answer questions such as: How can we target landscape stabilization projects to reduce turbidity? If we find that the most powerful weighting is associated with first order streams and cropland, we know conservation efforts should be focused on agricultural head waters.

  19. Transport of bromide and other inorganic ions by infiltrating storm water beneath a farmland plot

    SciTech Connect

    Iqbal, M.Z.; Krothe, N.C.

    1996-11-01

    A hydrogeochemical study in the clay-soil mantled portion of a karst terrane in southern Indiana demonstrated preferential flow of soil water through macropore structures that are of higher permeability than the soil matrix. Variable transport of several inorganic ions, such as Cl{sup {minus}}, SO{sub 4}{sup 2{minus}}, Na{sup +}, Ca{sup ++}, and Mg{sup ++}, through the unsaturated zone was observed immediately after a major storm event in April, 1992. A KBr salt spray experiment during the storm led to recovery of bromide, a nonreactive, conservative ion, at a depth of 10 ft within 24 hours after the storm. The observed Br{sup {minus}} transport rate (5 in/hr) is approximately six times greater than the expected rate of transport in the absence of preferential flow. Temporal changes in cation to anion ratios demonstrated that anions are more mobile due to the process of anionic exclusion which drives more anions out of the clay matrix whereas cations are attenuated by adsorption on the clay particles due to their charge differences. In the absence of storm-water infiltration, the ion transport proceeds largely by matrix flow of soil water. The storm event also initiated considerable mixing of ground water through lateral flow within the aquifer. The ions, such as Cl{sup {minus}}, NO{sub 3}{sup {minus}}, Ca{sup ++}, and Mg{sup ++}, showed immediate dilution by storm water. Subsequently, ion concentrations in the aquifer increased to the initial level because of reequilibrium with soil matrix water released from the lower part of the unsaturated zone.

  20. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J.

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  1. Methods for characterizing stream habitat as part of the National Water-Quality Assessment Program

    USGS Publications Warehouse

    Meador, Michael R.; Hupp, Cliff R.; Cuffney, Thomas F.; Gurtz, Martin E.

    1993-01-01

    Stream habitat is characterized in the U.S. Geological Survey?s National Water-Quality Assessment Program as part of an integrated physical, chemical, and biological assessment of the Nation?s water quality. The goal of stream habitat characterization is to relate habitat to other physical, chemical, and biological factors to describe water-quality conditions. To accomplish this goal, environmental settings are described at sites selected for water-quality assessment. In addition, spatial and temporal patterns in habitat are examined at local, regional, and national levels. Although habitat characterization is an important component of a number of Federal, State, and local water-quality assessment programs, no current set of habitat evaluation procedures meets the objectives of the habitat assessment component of the National Water-Quality Assessment Program. Evaluation of stream habitat is based on a spatially hierarchical framework that incorporates habitat data at basin, segment, reach, and microhabitat scales. This framework provides a basis for national consistency in collection techniques while allowing flexibility in habitat assessment within individual study units. Procedures are described for collecting habitat data at basin and stream segment scales that include use of geographic information system data bases, maps, and aerial photographs. Data collected at the stream reach scale include more than 34 riparian and instream habitat characteristics evaluated during onetime site visits, and surveys of the channel and riparian area during repeated sampling.

  2. Collection and analysis of inorganic and water soluble organic aerosols over Maryland and Virginia

    NASA Astrophysics Data System (ADS)

    Brent, L. C.; Ziemba, L. D.; Beyersdorf, A. J.; Phinney, K.; Conny, J.; Dickerson, R. R.

    2012-12-01

    Aerosols aloft have slower removal than those near the ground, in part, because dry and wet deposition rates result in longer lifetimes and greater range of influence. Knowledge of deposition rates and range of transport for different species are important for developing local and regional air quality policy. Currently, the vertical distribution of organic aerosols (OA's) and their polar, oxidized fraction is largely unknown. Comprehensive methods to analyze aerosol composition collected in the boundary layer and the lower free troposphere are lacking. During DISCOVER AQ 2011, both the NASA P3 and Cessna 402B collected aerosols, through shrouded aerosol inlets, onto Teflon and quartz fiber filters. Collection occurred in both the boundary layer and lower free troposphere over Maryland and Virginia, USA. After extraction with water and optimizing separation via ion chromatography, commonly identified secondary organic aerosols can be separated based on their functionality as mono-, di-, or polycarboxylic acids. Inorganic aerosol components can simultaneously be separated and identified with the same method. Individual organic acid compound analysis with detection limits in the low ppb range can be achieved when conductivity/ultraviolet/ and mass spectrometric detectors are placed in tandem. Additionally, thermo optical analysis can be used to determine the mass fraction of water soluble organic carbon versus the total collected mass. This research is designed to provide information on the vertical distribution of particulate organic carbon in the atmosphere, its optical properties, information on aerosol transport in the lower free troposphere, and to provide water soluble organic aerosol structural characterization.

  3. A coupled surface-water and ground-water flow model (MODBRANCH) for simulation of stream-aquifer interaction

    USGS Publications Warehouse

    Swain, Eric D.; Wexler, Eliezer J.

    1996-01-01

    Ground-water and surface-water flow models traditionally have been developed separately, with interaction between subsurface flow and streamflow either not simulated at all or accounted for by simple formulations. In areas with dynamic and hydraulically well-connected ground-water and surface-water systems, stream-aquifer interaction should be simulated using deterministic responses of both systems coupled at the stream-aquifer interface. Accordingly, a new coupled ground-water and surface-water model was developed by combining the U.S. Geological Survey models MODFLOW and BRANCH; the interfacing code is referred to as MODBRANCH. MODFLOW is the widely used modular three-dimensional, finite-difference ground-water model, and BRANCH is a one-dimensional numerical model commonly used to simulate unsteady flow in open- channel networks. MODFLOW was originally written with the River package, which calculates leakage between the aquifer and stream, assuming that the stream's stage remains constant during one model stress period. A simple streamflow routing model has been added to MODFLOW, but is limited to steady flow in rectangular, prismatic channels. To overcome these limitations, the BRANCH model, which simulates unsteady, nonuniform flow by solving the St. Venant equations, was restructured and incorporated into MODFLOW. Terms that describe leakage between stream and aquifer as a function of streambed conductance and differences in aquifer and stream stage were added to the continuity equation in BRANCH. Thus, leakage between the aquifer and stream can be calculated separately in each model, or leakages calculated in BRANCH can be used in MODFLOW. Total mass in the coupled models is accounted for and conserved. The BRANCH model calculates new stream stages for each time interval in a transient simulation based on upstream boundary conditions, stream properties, and initial estimates of aquifer heads. Next, aquifer heads are calculated in MODFLOW based on stream

  4. Organic and inorganic species in produced water: Implications for water reuse

    USGS Publications Warehouse

    Kharaka, Y.K.; Rice, C.A.

    2004-01-01

    Currently 20-30 billion bbl/yr of formation water are co-produced in the US with conventional oil and natural gas. The large database on the geochemistry of this produced water shows salinities that vary widely from ??? 5000 to > 350,000 mg/L TDS. Chloride, Na, and Ca are generally the dominant ions, and concentrations of Fe, Mn, B, NH3, and dissolved organics, including, BTEX, phenols and PAH may be relatively high. As an alternative to costly disposal, low salinity produced water is being considered for reclamation, especially in the arid western US. The cost of reclaiming this water to meet irrigation, industrial, and drinking water standards was evaluated in a 10 gpm pilot field study at Placerita oil field, CA. This produced water had low salinity but high concentration of Si and organics. Removal of B, Si, NH3, and especially organics from this water proved difficult, and the estimated treatment cost was high for water treated for industrial and municipal uses.

  5. Water temperatures within spawning beds in two chalk streams and implications for salmonid egg development

    NASA Astrophysics Data System (ADS)

    Acornley, R. M.

    1999-02-01

    Water temperatures within brown trout (Salmo trutta L.) spawning gravels were measured in two Hampshire chalk streams from October 1995 to April 1996 inclusive. During the winter, mean intra-gravel water temperatures were higher than those in the stream, and increased with depth in the gravel bed. The amplitude of diel fluctuations in water temperature decreased with depth in the gravel bed, although diel fluctuations were still evident at a depth of 30 cm. Differences in intra-gravel temperature gradients between the two study sites were attributed to differences in the amplitude of stream water temperature fluctuations and there was no evidence that either of the study sites were located in zones of upwelling groundwater. Published equations are used to predict, from temperature, the timing of important stages in the development of brown trout embryos (eyeing, hatching and emergence) for eggs spawned in the autumn and winter and buried at different depths in the gravel bed.

  6. Isotopic variations of dissolved copper and zinc in stream waters affected by historical mining

    USGS Publications Warehouse

    Borrok, D.M.; Nimick, D.A.; Wanty, R.B.; Ridley, W.I.

    2008-01-01

    Zinc and Cu play important roles in the biogeochemistry of natural systems, and it is likely that these interactions result in mass-dependent fractionations of their stable isotopes. In this study, we examine the relative abundances of dissolved Zn and Cu isotopes in a variety of stream waters draining six historical mining districts located in the United States and Europe. Our goals were to (1) determine whether streams from different geologic settings have unique or similar Zn and Cu isotopic signatures and (2) to determine whether Zn and Cu isotopic signatures change in response to changes in dissolved metal concentrations over well-defined diel (24-h) cycles. Average ??66Zn and ??65Cu values for streams varied from +0.02??? to +0.46??? and -0.7??? to +1.4???, respectively, demonstrating that Zn and Cu isotopes are heterogeneous among the measured streams. Zinc or Cu isotopic changes were not detected within the resolution of our measurements over diel cycles for most streams. However, diel changes in Zn isotopes were recorded in one stream where the fluctuations of dissolved Zn were the largest. We calculate an apparent separation factor of ???0.3??? (66/64Zn) between the dissolved and solid Zn reservoirs in this stream with the solid taking up the lighter Zn isotope. The preference of the lighter isotope in the solid reservoir may reflect metabolic uptake of Zn by microorganisms. Additional field investigations must evaluate the contributions of soils, rocks, minerals, and anthropogenic components to Cu and Zn isotopic fluxes in natural waters. Moreover, rigorous experimental work is necessary to quantify fractionation factors for the biogeochemical reactions that are likely to impact Cu and Zn isotopes in hydrologic systems. This initial investigation of Cu and Zn isotopes in stream waters suggests that these isotopes may be powerful tools for probing biogeochemical processes in surface waters on a variety of temporal and spatial scales.

  7. Influence of Solar Exposure on Stream Water Temperature: Implications for Conservation

    NASA Astrophysics Data System (ADS)

    Rich, P. M.; Weiss, S. B.; Launer, A. E.

    2007-12-01

    Stream water temperature is determined by a complex interplay of prevailing meteorology, local riparian canopy structure as it affects solar exposure, streambed morphology, and surface and subsurface flow patterns. We examined spatio-temporal variation in temperature regimes with respect to conservation of aquatic organisms of San Francisquito Creek (San Francisco Peninsula, California). Analyses synthesized measurements of meteorology from nearby weather stations, water temperature from a network of sensors, riparian canopy structure and solar exposure from hemispherical (fisheye) photography, stream morphology from field characterization and geographic information system (GIS) analysis, and stream flow and water temperature from gauging stations. We modeled stream temperature dynamics based on energy balance, with a focus on energy input from solar radiation. Water temperature co-varied with air temperature, with diurnal and seasonal lags. Stream reaches with high solar exposure displayed relatively high temperature variability (up to 5° C differential from baseline), whereas shaded reaches displayed only modest temperature variability (0.5-1.0° C differential). Subsurface flow through gravel beds decreased temperature (2-3° C decrease). Management of stream habitat to include a diversity of suitable temperature regimes is essential for conservation of species such as steelhead trout ( Oncorhynchus mykiss), which requires relatively cool conditions, and California red-legged frog ( Rana aurora draytonii) and western pond turtle ( Clemmys marmorata), which require warmer conditions. This approach can be applied to a broad spectrum of streams for habitat assessment, for stream conservation and restoration to accommodate diverse habitat needs, and for examination of potential impacts of climate change.

  8. UNIVERSITY OF WISCONSIN - PHOTO ELECTRO CATALYTIC DEGRADATION AND REMOVAL OFORGANIC AND INORGANIC CONTAMINANTS IN GROUND WATERS: SITE DOC

    EPA Science Inventory

    SITE DOC NRMRL-CIN-1338 Gallardo*, V. University of Wisconsin - Photo Electro Catalytic Degradation and Removal of Organic and Inorganic Contaminants in Ground Waters. 2001. EPA/540/R-01/502, http://www.epa.gov/ORD/SITE. 02/22/2001 Photocatalytic oxidation offers a means of...

  9. TREATMENT TECHNOLOGY TO MEET THE INTERIM PRIMARY DRINKING WATER REGULATIONS FOR INORGANICS, PART 3. CADMIUM, LEAD, AND SILVER

    EPA Science Inventory

    EPA established drinking water regulations for ten inorganic substances and radionuclides that became effective on June 24, 1977. As a result of these new regulations, many communities may be required to construct new treatment facilities or to modify existing ones. This paper on...

  10. Determining Critical Water Quality Conditions For Inorganic Nitrogen in Dry Semi-urbanized Watersheds

    NASA Astrophysics Data System (ADS)

    Herr, J.; Keller, A. A.; Zheng, Y.; Robinson, T. H.

    2004-12-01

    Traditional approaches to establishing critical water quality conditions, based on statistical analysis of low flow conditions and expressed as a recurrence interval for low-flow conditions (e.g. 7Q10), may be inappropriate for drier watersheds. The use of 7Q10 as a standard design flow assumes year-round flow, but in these watersheds 7Q10 is zero or very small. In addition, the increasing use of multiple year dynamic water quality models at daily time steps, can supercede the use of steady-state approaches. Many of these watersheds are also under increasing urbanization pressure, which accentuates the flashiness of runoff and the episodic nature of critical water quality conditions. To illustrate, we consider the conditions in the Santa Clara River, California. A statistical analysis indicates that higher inorganic nitrogen concentrations correlate strongly with low flow. However, peaks in concentrations can occur during the first storms, particularly where non-point source contribution is significant. Critical conditions can thus occur at different flow regimes depending on the relative magnitude of flow and pollutant contributions from various sources. The use of steady-state models for these dry semi-urbanized watersheds based on 7Q10 flows is thus unlikely to accurately simulate the potential for exceeding water quality objectives. Dynamic simulation of water quality is necessary, and as the recent intense storm event sampling data indicates, the models should be formulated to consider even smaller time steps. This places increasing demand on computational resources and datasets to accurately calibrate the models at this temporal resolution.